Antimicrobial Prescribing Policy
Hospital Antimicrobial Stewardship Program β’ Evidence-Based Antimicrobial Guidelines for Adult Patients
Drug Information Center β’ Dr. Marwa Ahmed | Dr. Heba Hassan | Dr. Ahmed Khaled
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1. Community-Acquired Pneumonia (CAP)
βΌ
Treatment of CAP in adults who require hospitalization. Streptococcus pneumoniae and respiratory viruses are the most frequently detected pathogens.
| Drug | Dose |
|---|---|
| First Line | |
| Ceftriaxone | 1 to 2 g IV daily |
| Cefotaxime | 1 to 2 g IV every 8 hours |
| Ampicillin-Sulbactam | 3 g IV every 6 hours |
| Plus | |
| Azithromycin | 500 mg IV or orally daily |
| Clarithromycin | 500 mg twice daily |
| Alternative (Monotherapy) | |
| Levofloxacin | 750 mg IV or orally daily |
| Moxifloxacin | 400 mg IV or orally daily |
| Gemifloxacin | 320 mg orally daily |
| If Contraindications to Both Macrolides and Fluoroquinolones | |
| Beta-lactam + Doxycycline | 100 mg orally or IV twice daily |
Risk factors: Known Pseudomonas colonization/prior infection, GNR on sputum Gram stain, hospitalization with IV antibiotics in prior 3 months, long-term care, frequent COPD exacerbations, structural lung disease (bronchiectasis, CF), immunosuppression.
| Drug | Dose |
|---|---|
| Antipseudomonal Beta-Lactam (choose one) | |
| Piperacillin-Tazobactam | 4.5 g every 6 hours |
| Imipenem | 500 mg every 6 hours |
| Meropenem | 1 g every 8 hours |
| Cefepime | 2 g every 8 hours |
| Ceftazidime | 2 g every 8 hours |
| Plus (Fluoroquinolone) | |
| Ciprofloxacin | IV 400 mg every 8 hours |
| Levofloxacin | 750 mg daily |
Risk factors: Recent hospitalization/IV antibiotics in prior 3 months, recent influenza-like illness, necrotizing/cavitary pneumonia, empyema, known MRSA colonization/prior infection, GPC in clusters on sputum Gram stain.
ADD to the above regimen:
| Drug | Dose |
|---|---|
| Vancomycin | (15β20) mg/kg q12h |
| Linezolid | 600 mg q12h |
| Drug | Dose |
|---|---|
| Beta-Lactam (choose one) | |
| Ceftriaxone | 1 to 2 g IV daily |
| Cefotaxime | 1 to 2 g IV every 8 hours |
| Ampicillin-Sulbactam | 3 g IV every 6 hours |
| Ertapenem | 1 g IV daily |
| Plus | |
| Azithromycin | 500 mg IV or orally daily |
| Or | |
| Levofloxacin | 750 mg IV or orally daily |
| Moxifloxacin | 400 mg IV or orally daily |
Severe ICU-CAP with suspected MRSA/Pseudomonas requires a distinct regimen (not identical to ward management).
| Drug | Dose | Notes |
|---|---|---|
| Antipseudomonal Beta-Lactam (choose one) | ||
| Piperacillin-Tazobactam | 4.5 g every 6 hours | |
| Cefepime | 2 g every 8 hours | |
| Ceftazidime | 2 g every 8 hours | |
| Imipenem | 500 mg every 6 hours | |
| Meropenem | 1 g every 8 hours | |
| Plus Anti-MRSA Agent (if MRSA suspected) | ||
| Vancomycin | (15β20) mg/kg q12h | |
| Linezolid | 600 mg q12h | |
| Plus (Macrolide or Respiratory FQ) | ||
| Azithromycin | 500 mg IV daily | Preferred for atypical coverage |
| Levofloxacin | 750 mg IV daily | Alternative |
| Moxifloxacin | 400 mg IV daily | Alternative |
References: ATS/IDSA CAP Guidelines 2019 β UpToDate
2. Hospital-Acquired Pneumonia (HAP) & Ventilator-Associated Pneumonia (VAP)
βΌ
Cause: Commonly MDROs like P. aeruginosa, Acinetobacter, and MRSA.
Severe HAP is defined as: need for IV vasopressors (septic shock) OR need for mechanical ventilation due to pneumonia.
| Drug | Dose |
|---|---|
| Anti-MRSA (choose one) | |
| Vancomycin | 15 to 20 mg/kg every 8 to 12 hours |
| Linezolid | 600 mg IV every 12 hours |
| Plus β a) History of Carbapenem-Resistant Pathogens | |
| Ceftazidime-Avibactam | 2.5 g IV every 8 hours |
| Alternative (if ceftazidime-avibactam unavailable): along with a carbapenem | |
| Colistin | Loading: 300β360 mg CBA Γ 1, then maintenance: 160β240 mg CBA/day Γ· q12h (adjust for CrCl) |
| Aztreonam | 2 g IV every 8 hours |
| Levofloxacin | 750 mg IV or orally daily |
| Ciprofloxacin | 400 mg IV every 8 hours or 750 mg orally every 12 hours |
| Plus β b) No History of Carbapenem-Resistant Pathogens | |
| Meropenem | 1 g IV every 8 hours |
| Imipenem-Cilastatin | 500 mg IV every 6 hours |
β Note: Colistin: Renal dose adjustment is MANDATORY to avoid nephrotoxicity. Always adjust based on CrCl.
| Drug | Dose |
|---|---|
| No Risk of MDR | |
| Piperacillin-Tazobactam | 4.5 g IV every 6 hours |
| Cefepime | 2 g IV every 8 hours |
| Plus, if Risk of MRSA (β₯20% MRSA isolates, unknown susceptibility, or prior MRSA colonization) | |
| Vancomycin | 15β20 mg/kg/(8β12h) IV |
| Linezolid | 600 mg q12h IV |
| Risk of MDR: a) History of Carbapenem-Resistant Pathogens | |
| Ceftazidime-Avibactam | 2.5 g IV every 8 hours |
| Alternative (if unavailable): along with a carbapenem | |
| Colistin | Loading: 300β360 mg CBA Γ 1, then 160β240 mg CBA/day Γ· q12h (adjust for CrCl) |
| Aztreonam | 2 g IV every 8 hours |
| Levofloxacin | 750 mg IV or orally daily |
| Ciprofloxacin | 400 mg IV every 8 hours or 750 mg orally every 12 hours |
| b) No History of Carbapenem-Resistant Pathogens | |
| Meropenem | 1 g IV every 8 hours |
| Imipenem-Cilastatin | 500 mg IV every 6 hours |
| Plus, if Risk of MRSA (β₯20% MRSA isolates, unknown susceptibility, or prior MRSA colonization) | |
| Vancomycin | 15β20 mg/kg/(8β12h) IV |
| Linezolid | 600 mg q12h IV |
MDR risk: susceptibility unknown, >10% GNB resistant to cefepime/piperacillin-tazobactam, MDR GNB colonization from respiratory tract or other site.
References: ATS/IDSA HAP-VAP Guidelines 2016 β UpToDate
3. Aspiration Pneumonia
βΌ
Community-acquired aspiration pneumonia requiring hospitalization.
| Drug | Dose |
|---|---|
| First Line | |
| Ampicillin-Sulbactam | 1.5 to 3 g IV every 6 hours |
| Alternative | |
| Ceftriaxone | 1 or 2 g daily |
| Cefotaxime | 1 or 2 g every 8 hours |
| Plus | |
| Metronidazole | IV 500 mg every 8 hours |
| Drug | Dose |
|---|---|
| Antipseudomonal Beta-Lactam (choose one) | |
| Piperacillin-Tazobactam | 4.5 g IV every 6 hours |
| Imipenem | 500 mg IV every 6 hours |
| Meropenem | 1 g IV every 8 hours |
| Plus: MRSA Coverage (if risk factors present) | |
| Vancomycin | (15β20) mg/kg q12h |
| Linezolid | 600 mg q12h |
MRSA risk factors: recent hospitalization/IV antibiotics in prior 3 months, recent influenza-like illness, necrotizing/cavitary pneumonia, empyema, known MRSA colonization/prior infection, GPC in clusters on sputum Gram stain.
Hospital-acquired aspiration pneumonia requires MDR-organism coverage (Pseudomonas, Acinetobacter, MRSA). Treat with an antipseudomonal beta-lactam Β± anti-MRSA agent Β± anaerobic coverage, as per HAP/VAP protocol (Section 3). Do NOT equate with community-acquired aspiration pneumonia.
References: ATS/IDSA HAP Guidelines 2016 β UpToDate
4. Urinary Tract Infection (UTI)
βΌ
Relevant uropathogens: primarily E. coli, but also other Enterobacterales, other GNB (including P. aeruginosa), staphylococci, enterococci.
1) Patients Without MDR Risk Factors β Start empiric antibiotic therapy without obtaining culture
| Drug | Dose | Duration | Notes |
|---|---|---|---|
| Nitrofurantoin | 100 mg PO BID | F: 5d / M: 7d | Avoid if CrCl <30 mL/min |
| TMP-SMX | 1 DS (160/800 mg) PO BID | F: 3d / M: 7d | Useful for males with concern for prostatitis |
| Fosfomycin | 3 g | Single dose | |
| Alternatives | |||
| Amoxicillin-Clavulanate | 500 mg BID | F: 5β7d / M: 7d | |
| Cefpodoxime | 100 mg BID | F: 5β7d / M: 7d | |
| Cefadroxil | 500 mg BID | F: 5β7d / M: 7d | |
| Fluoroquinolones (avoid if other options available due to serious adverse effects) | |||
| Ciprofloxacin | 250 mg BID or 500 mg ER daily | F: 3d / M: 5d | Useful for males with prostatitis concern |
| Levofloxacin | 250 mg daily | F: 3d / M: 5d | |
2) Patients With MDR Risk Factors β Obtain urine culture and start empiric therapy
MDR risk (any in prior 3 months): MDR GN urinary isolate, inpatient stay, use of FQ/TMP-SMX/broad-spectrum beta-lactam, travel to regions with high MDR rates.
| Drug | Dose | Duration |
|---|---|---|
| Nitrofurantoin | 100 mg PO BID | F: 5d / M: 7d |
| Fosfomycin | 3 g | Single dose |
Alternatives: Treat empirically with an oral agent initially avoided due to resistance concerns while awaiting culture/susceptibility. If concerns about treatment failure (underlying urologic or immunocompromising condition), treat with an initial parenteral agent as for complicated UTI.
Infection beyond the bladder. Features suggesting extension: fever (>37.7Β°C), chills/rigors, significant fatigue, flank pain, CVA tenderness, pelvic/perineal pain in males.
1) Hospitalized β Critical Illness or Urinary Tract Obstruction
| Drug | Dose | Duration |
|---|---|---|
| a) If ESBL Prevalence High or Uncertain | ||
| Imipenem | 500 mg IV q6h or 1 g IV q8h (3h infusion) | 5β7 days |
| Meropenem | 1 to 2 g IV q8h (3h infusion) | |
| Plus β Anti-MRSA | ||
| Vancomycin | 15β20 mg/kg IV q8β12h Β± loading dose | |
| Linezolid (Alt.) | IV or PO 600 mg q12h | |
| b) If ESBL Prevalence Low (<10%) β Select regimen based on individual MDR risk as per "Other Hospitalized Patients" | ||
2) Other Hospitalized Patients
| Drug | Dose | Notes |
|---|---|---|
| No MDR Risk | ||
| Ceftriaxone | 1 to 2 g IV once daily | |
| Alternatives | ||
| Levofloxacin | 500 to 750 mg IV or PO daily | |
| Ciprofloxacin | IV: 400 mg BID / PO: 500β750 mg BID / ER: 1000 mg daily | |
| MDR Risk | ||
| Piperacillin-Tazobactam | 3.375 g IV q6h or 4.5 g IV q8h | If prior ESBL UTI + severely ill: favor carbapenem. Add vancomycin (MRSA) or daptomycin/linezolid (VRE) if suspected. |
| Cefepime | 1 g IV q12h or 2 g IV q8β12h | |
| Imipenem | 500 mg IV q6h (3h infusion) | |
| Meropenem | 1 to 2 g IV q8h (3h infusion) | |
1. Asymptomatic Bacteriuria
Antibiotic options are the same as those used to treat cystitis.
2. Cystitis (Bladder Infection)
| Drug | Dose | Duration | Notes |
|---|---|---|---|
| Amoxicillin | 500 mg PO q8h or 875 mg PO q12h | 5β7 days | Resistance may limit utility for GN pathogens |
| Amoxicillin-Clavulanate | 500 mg PO q8h or 875 mg PO q12h | 5β7 days | |
| Cefpodoxime | 100 mg PO q12h | 5β7 days | |
| Cephalexin | 250β500 mg PO q6h | 5β7 days | |
| Nitrofurantoin | 100 mg PO q12h | 5β7 days | |
| TMP-SMX | 800/160 mg q12h | 5β7 days | Typically avoided during first trimester |
| Fosfomycin | 3 g PO | Single dose | Not for pyelonephritis (inadequate renal levels) |
3. Pyelonephritis
Features: flank pain, nausea/vomiting, fever >38Β°C, CVA tenderness Β± cystitis symptoms, confirmed by bacteriuria.
| Drug | Dose | Notes |
|---|---|---|
| First Line | ||
| Ceftriaxone | 1 to 2 g IV q24h | |
| Alternatives | ||
| Cefepime | 1 to 2 g IV q12h | For patients with risk for ceftriaxone-resistant organisms |
| Piperacillin-Tazobactam | 3.375 g IV q6h or 4.5 g IV q8h | |
| Meropenem | 1 g q8h (3h infusion); 2 g q8h for prior MDR isolates | Reserve for resistance/critical infection |
| Ertapenem | 1 g q24h | |
| Aztreonam | 1 g q8h | For patients who cannot use beta-lactam |
Treat Asymptomatic Bacteriuria ONLY if:
- Pregnant
- Patients undergoing TURP or other urologic procedures with anticipated mucosal bleeding
β Note: Per IDSA 2019 guidelines, routine treatment of ASB in kidney transplant recipients (including the first 6 months post-transplantation) is no longer recommended. This represents an update from prior guidelines.
1. Asymptomatic Candiduria
Removal of catheter/stent should be considered. Treat with antifungal ONLY if:
- Neutropenia
- Very low birth weight infants
- Urinary tract manipulation
- Transplant recipients/diabetes mellitus/immunosuppression
2. Symptomatic Candiduria
| Indication | Drug & Dose |
|---|---|
| Cystitis | Fluconazole oral 200 mg (3 mg/kg)/24h |
| Pyelonephritis | Fluconazole 200 to 400 mg (3β6 mg/kg)/24h |
References: UpToDate β IDSA β IDSA ASB Guidelines 2019 (Nicolle et al.)
5. Acute Cellulitis and Erysipelas in Adults & Skin Abscesses
βΌ
Beta-hemolytic streptococci cause most cases; cellulitis is sometimes caused by S. aureus.
| Drug | Dose |
|---|---|
| Broad-Spectrum Beta-Lactam (choose one) | |
| Cefepime | 2 g every 8 hours |
| Piperacillin-Tazobactam | 4.5 g every 6 hours |
| Meropenem | 1 g every 8 hours |
| Imipenem-Cilastatin | 500 mg q6h or 1 g q8h |
| Plus Anti-MRSA | |
| Vancomycin | 20β35 mg/kg LD, then 15β20 mg/kg IV q8β12h |
| Daptomycin | 4β6 mg/kg IV q24h |
| Alternative | |
| Linezolid | 600 mg every 12 hours |
| Oral Switch (once clinically improved) | |
| Dicloxacillin | 500 mg PO q6h |
| Cephalexin | 500 mg PO q6h |
| Cefadroxil | 500 mg PO q12h or 1 g PO daily |
| TMP-SMX | 2 DS tablets BID |
| Amoxicillin + Doxycycline | 875 mg q12h + 100 mg q12h |
| Linezolid (Alt.) | 600 mg q12h |
| Clindamycin (Alt.) | 450 mg q8h |
| Drug | Dose |
|---|---|
| Without Indication for MRSA Coverage | |
| Cefazolin | 1 to 2 g every 8 hours |
| Nafcillin | 1 to 2 g every 4 hours |
| Oxacillin | 1 to 2 g every 4 hours |
| Flucloxacillin | 2 g every 6 hours |
| Vancomycin (severe beta-lactam allergy) | 20β35 mg/kg LD, then 15β20 mg/kg IV q8β12h |
| With Indication for MRSA Coverage | |
| Vancomycin | 20β35 mg/kg LD, then 15β20 mg/kg IV q8β12h |
| Daptomycin | 4β6 mg/kg IV q24h |
| Alternative | |
| Linezolid | 600 mg every 12 hours |
| Oral Switch (once clinically improved) | |
| Dicloxacillin | 500 mg PO q6h |
| Cephalexin | 500 mg PO q6h |
| Cefadroxil | 500 mg PO q12h or 1 g PO daily |
| TMP-SMX | 2 DS tablets BID |
| Amoxicillin + Doxycycline | 875 mg q12h + 100 mg q12h |
| Linezolid (Alt.) | 600 mg q12h |
| Clindamycin (Alt.) | 450 mg q8h |
MRSA indications: systemic toxicity (fever >38Β°C, sustained tachycardia), purulent wound drainage, injection drug use, known MRSA colonization/infection.
Parenteral antibiotic regimens for higher risk patients, typically started prior to I&D.
| Drug | Dose |
|---|---|
| Parenteral | |
| Vancomycin | 20β35 mg/kg LD, then 15β20 mg/kg IV q8β12h |
| Daptomycin | 4β6 mg/kg IV q24h |
| Alternative | |
| Linezolid | 600 mg every 12 hours |
| Oral Switch | |
| TMP-SMX | 2 DS tablets BID |
| Doxycycline | 100 mg PO BID |
| Clindamycin | 450 mg PO q8h |
Special Populations: Patients with severe illness, certain comorbidities, or atypical infection locations: treat as suggested for cellulitis.
References: UpToDate β IDSA Practice Guideline: Skin and Soft Tissue Infections
6. Necrotizing Fasciitis
βΌ
Caused by GAS, S. aureus, E. coli, Klebsiella, Clostridium, Aeromonas hydrophila.
| Drug | Dose |
|---|---|
| Broad-Spectrum (choose one) | |
| Imipenem | 1 g IV every 6 to 8 hours |
| Meropenem | 1 g IV every 8 hours |
| Piperacillin-Tazobactam | 3.375 g q6h or 4.5 g q8h |
| Plus Anti-MRSA (choose one) | |
| Vancomycin | 15β20 mg/kg/dose q8β12h |
| Daptomycin | 4β6 mg/kg IV once daily |
| Alternative to Vancomycin/Daptomycin | |
| Linezolid | 600 mg q12h |
| Plus (NOT with Linezolid) | |
| Clindamycin | 600 to 900 mg IV every 8 hours |
References: UpToDate β IDSA Practice Guideline: Skin and Soft Tissue Infections
7. Diabetic Foot Infections (DFIs)
βΌ
Patient systemically well and metabolically stable, with β₯1: cellulitis >2 cm, lymphangitic streaking, spread beneath superficial fascia, deep-tissue abscess, gangrene, or muscle/tendon/joint/bone involvement.
| Drug | Dose |
|---|---|
| Standard Coverage | |
| Ceftriaxone + Metronidazole | 2 g IV daily + 500 mg IV q8β12h |
| Ceftazidime + Metronidazole | 1β2 g q8h + 500 mg IV q8β12h |
| Cefepime + Metronidazole | 2 g q8β12h + 500 mg IV q8h |
| Ampicillin-Sulbactam | 3 g every 6 hours |
| Piperacillin-Tazobactam | 3.375 g IV q6h |
| If Indication for Pseudomonas Coverage | |
| Cefepime + Metronidazole | 2 g q8β12h + 500 mg IV q8h |
| Piperacillin-Tazobactam | 4.5 g IV q6h |
| Meropenem | 1 g every 8 hours |
| Imipenem-Cilastatin | 500 mg every 6 hours |
| If Indication for MRSA Coverage β ADD | |
| Vancomycin | 15β20 mg/kg q8β12h |
| Linezolid | 600 mg q12h |
| Daptomycin | 4β6 mg/kg q24h |
Pseudomonas indications: superficial necrosis with moist/pus appearance, significant water exposure, warm tropical/subtropical exposure, or Pseudomonas from a deep specimen.
Patient with systemic toxicity or metabolic instability (fever, chills, tachycardia, hypotension, confusion, vomiting, leukocytosis, acidosis, severe hyperglycemia, or azotemia).
| Drug | Dose |
|---|---|
| Broad-Spectrum (choose one) | |
| Cefepime + Metronidazole | 2 g q8β12h + 500 mg IV q8h |
| Piperacillin-Tazobactam | 4.5 g IV q6h |
| Meropenem | 1 g every 8 hours |
| Imipenem-Cilastatin | 500 mg every 6 hours |
| Plus Anti-MRSA (choose one) | |
| Vancomycin | 15β20 mg/kg q8β12h |
| Linezolid | 600 mg q12h |
| Daptomycin | 4β6 mg/kg q24h |
References: IDSA Practice Guideline β Diabetic Foot Infections
8. Intra-Abdominal Infections
βΌ
Most cases caused by enteric bacteria (E. coli, K. pneumoniae, E. faecalis, E. faecium).
1) Without Critical Illness or Risk of MDROs (Community-Acquired)
| Drug | Dose |
|---|---|
| Ceftriaxone | 2 g IV q24h |
| Cefotaxime | 2 g IV q8h |
| Alternatives | |
| Ciprofloxacin | 400 mg IV BID (not if on FQ prophylaxis) |
| Piperacillin-Tazobactam | 4.5 g IV q6h (non-critically ill with MDR GN risk) |
2) Critical Illness (Septic Shock) or Risk Factors for MDR GNB
MDRO risk: known colonization/prior MDRO infection, nosocomial SBP, recent hospitalization/beta-lactam use (prior 3 months), frequent healthcare contact.
| Drug | Dose |
|---|---|
| Carbapenem | |
| Meropenem | 1 g IV q8h |
| Imipenem-Cilastatin | 500 mg IV q6h |
| Plus: a) If Risk of MRSA | |
| Vancomycin | 15β20 mg/kg IV q8β12h |
| b) If Risk of VRE | |
| Daptomycin | 4β6 mg/kg IV q24h |
Predominant bacteria: coliforms (E. coli, Klebsiella, Proteus, Enterobacter), streptococci, enterococci, anaerobes.
Mildβmoderate (e.g., perforated appendix/appendiceal abscess) without resistance risk factors.
| Drug | Dose |
|---|---|
| Piperacillin-Tazobactam | 3.375 g IV q6h |
| Or: Metronidazole + one of the following | |
| Metronidazole | 500 mg IV or PO q8h |
| Plus | |
| Cefazolin | 1β2 g IV q8h |
| Ceftriaxone | 2 g IV daily |
| Cefotaxime | 2 g IV q8h |
| Ciprofloxacin | 400 mg IV q12h or 500 mg PO q12h |
| Levofloxacin | 750 mg IV or PO daily |
APACHE II >15 or β₯1 host/disease risk factor (age >70, immunocompromise, diffuse peritonitis, delay in source control >24h).
| Drug | Dose |
|---|---|
| Piperacillin-Tazobactam | 4.5 g IV q6h |
| Or | |
| Metronidazole | 500 mg IV or PO q8h |
| Plus | |
| Cefepime | 2 g IV q8h |
| Ceftazidime | 2 g IV q8h |
Onset >48h post-admission, hospitalization within 90 days, long-term care residence, or recent invasive therapy.
| Drug | Dose |
|---|---|
| Option 1 | |
| Imipenem-Cilastatin | 500 mg IV q6h |
| Meropenem | 1 g IV q8h |
| Piperacillin-Tazobactam | 4.5 g IV q6h |
| Or: Metronidazole + Antipseudomonal Cephalosporin | |
| Metronidazole | 500 mg IV or PO q8h |
| Plus | |
| Cefepime | 2 g IV q8h |
| Ceftazidime | 2 g IV q8h |
| Plus: If Risk of MRSA β ADD | |
| Vancomycin | 15β20 mg/kg IV q8β12h |
9. Catheter-Related Bloodstream Infection (CRBSI)
βΌ
Commonly caused by S. aureus or Candida species.
| Drug | Dose | Notes |
|---|---|---|
| 1. Anti-MRSA | ||
| Vancomycin (First line) | Loading: 20β30 mg/kg IV, then 15β20 mg/kg IV q8β12h | |
| Daptomycin (Alt.) | 8 to 10 mg/kg once daily | Also for units with high VRE rates |
| Linezolid | NOT appropriate for empiric CRBSI therapy | Linezolid is bacteriostatic (not bactericidal) β unsuitable for bacteremia/endovascular infections where bactericidal activity is essential |
| 2. Plus Antipseudomonal Beta-Lactam | ||
| Ceftazidime | 2 g every 8 hours | Extended/continuous infusion in critical illness or elevated MIC |
| Cefepime | 2 g every 8 hours | |
| Piperacillin-Tazobactam | 4.5 g every 6 hours | |
| Imipenem-Cilastatin | 500 mg q6h or 1 g q8h | |
| Meropenem | 1 to 2 g every 8 hours | |
| 3. Second Antipseudomonal (if hemodynamic instability, <90% local susceptibility, neutropenia, or MDR colonization) | ||
| Gentamicin | 5β7 mg/kg once daily | Should not be used as monotherapy |
| Amikacin | 15β30 mg/kg once daily | |
| Ciprofloxacin | 400 mg q8h | |
| 4. Antifungal (if risk factors: TPN, prolonged broad-spectrum ABs, hematologic malignancy, BMT/SOT, femoral catheter, multisite Candida colonization) | ||
| Caspofungin | 70 mg LD then 50 mg MD | |
| Fluconazole | Loading: 800 mg (12 mg/kg) day 1, then 400 mg daily (6 mg/kg/day) | If not critically ill; no azole exposure in prior 3 months |
References: UpToDate β IDSA CRBSI Guidelines 2009
10. CNS Infections
βΌ
Bacterial infections: S. pneumoniae, N. meningitidis.
| Drug | Dose |
|---|---|
| Ceftriaxone | 2 g IV q12h |
| Cefotaxime | 2 g IV q4β6h |
| Plus | |
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Plus (if age >50 years) | |
| Ampicillin | 2 g every 4 hours |
| Predisposing Factor | Drug | Dose |
|---|---|---|
| Head trauma / Basilar skull fracture | Vancomycin + Ceftriaxone OR Cefotaxime | 15β20 mg/kg q8β12h + 2 g q12h OR 2 g q4β6h |
| Penetrating trauma | Vancomycin + Cefepime OR Ceftazidime OR Meropenem | 15β20 mg/kg q8β12h + 2 g q8h |
| Post-neurosurgery | Vancomycin + Cefepime OR Ceftazidime OR Meropenem | 15β20 mg/kg q8β12h + 2 g q8h |
| CSF shunt | Vancomycin + Cefepime OR Ceftazidime OR Meropenem | 15β20 mg/kg q8β12h + 2 g q8h |
| Drug | Dose |
|---|---|
| Vancomycin | 15β20 mg/kg q8β12h |
| Plus | |
| Ampicillin | 2 g every 4 hours |
| Plus | |
| Cefepime | 2 g every 8 hours |
| or Meropenem | 2 g every 8 hours |
| Organism / Susceptibility | Standard Therapy | Alternative Therapies |
|---|---|---|
| Streptococcus pneumoniae | ||
| Penicillin MIC β€0.06 mcg/mL | Penicillin G or Ampicillin | 3rd-gen cephalosporin, Chloramphenicol |
| Pen β₯0.12 / Ceph MIC <1 mcg/mL | 3rd-gen cephalosporin | Cefepime, Meropenem |
| 3rd-gen cephalosporin MIC β₯1 mcg/mL | Vancomycin + 3rd-gen cephalosporin | Fluoroquinolone |
| Neisseria meningitidis | ||
| Penicillin MIC <0.1 mcg/mL | Penicillin G or Ampicillin | 3rd-gen cephalosporin, Chloramphenicol |
| 0.1 to 1.0 mcg/mL | 3rd-gen cephalosporin | FQ, Meropenem, Chloramphenicol |
| Other Organisms | ||
| Listeria monocytogenes | Ampicillin or Penicillin G | TMP-SMX |
| Group B Streptococcus | Ampicillin or Penicillin G | 3rd-gen cephalosporin |
| E. coli / Enterobacteriaceae | 3rd-gen cephalosporin | Aztreonam, FQ, Meropenem, TMP-SMX, Ampicillin |
| Pseudomonas aeruginosa | Cefepime or Ceftazidime | Aztreonam, Ciprofloxacin, Meropenem |
| Acinetobacter baumannii | Meropenem | Colistin or Polymyxin B |
| Haemophilus influenzae | ||
| Beta-lactamase negative | Ampicillin | 3rd-gen ceph, Cefepime, FQ, Aztreonam |
| Beta-lactamase positive | 3rd-gen cephalosporin | Cefepime, FQ, Aztreonam, Chloramphenicol |
| Staphylococcus aureus | ||
| Methicillin susceptible | Nafcillin or Oxacillin | Vancomycin, Meropenem, Linezolid, Daptomycin |
| Methicillin resistant | Vancomycin | TMP-SMX, Linezolid, Daptomycin |
| S. epidermidis | Vancomycin | Linezolid |
| Enterococcus species | ||
| Ampicillin susceptible | Ampicillin + Gentamicin | |
| Ampicillin resistant | Vancomycin + Gentamicin | |
| Ampicillin + Vancomycin resistant | Linezolid | |
Recommended IV doses for adults with bacterial meningitis and normal renal/hepatic function:
| Drug | Dose |
|---|---|
| Amikacin | 15β20 mg/kg/day (once daily or divided) |
| Ampicillin | 2 g every 4 hours |
| Aztreonam | 2 g every 6 to 8 hours |
| Cefepime | 2 g every 8 hours |
| Cefotaxime | 2 g every 4 to 6 hours |
| Ceftazidime | 2 g every 8 hours |
| Ceftriaxone | 2 g every 12 hours |
| Ciprofloxacin | 400 mg every 8 to 12 hours |
| Gentamicin | 1.7 mg/kg every 8 hours |
| Levofloxacin | 750 mg once daily |
| Meropenem | 2 g every 8 hours |
| Moxifloxacin | 400 mg every 24 hours |
| Nafcillin | 2 g IV every 4 hours |
| Oxacillin | 2 g IV every 4 hours |
| Rifampin | 600 mg every 24 hours |
| TMP-SMX | 5 mg/kg every 8 hours |
| Vancomycin | 15β20 mg/kg every 8 to 12 hours |
Primarily caused by Herpes Simplex Virus.
| Drug | Dose |
|---|---|
| Acyclovir | 10 mg/kg IV every 8 hours |
β CRITICAL: Acyclovir causes nephrotoxicity and neurotoxicity in renal impairment. Dose MUST be reduced based on CrCl (e.g., CrCl <25 mL/min: 10 mg/kg q24h). Use ideal or adjusted body weight for dosing in obesity to avoid overdosing.
References: IDSA β UpToDate β Lexicomp
11. Infective Endocarditis
βΌ
Native Valve Endocarditis (NVE)
| Drug | Dose |
|---|---|
| Vancomycin | 30 mg/kg/day IV in 2 doses |
| Plus | |
| Ceftriaxone | 2 g/day IV in 1 dose |
| Or Alternative | |
| Ampicillin-Sulbactam (if GI source risk) | 12 g/day IV in 4β6 doses |
| If Pseudomonas risk | |
| Piperacillin-Tazobactam | 4.5 g q6h |
| or Cefepime | 2 g q6h |
Prosthetic Valve Endocarditis (PVE)
| Drug | Dose |
|---|---|
| Vancomycin | 30 mg/kg/day IV in 2 doses |
| or Daptomycin | 10 mg/kg/day IV in 1 dose |
| Plus β if Pseudomonas risk | |
| Piperacillin-Tazobactam | 4.5 g q6h |
| or Cefepime | 2 g q6h |
| Plus (if healthcare-associated) | |
| Gentamicin | 3 mg/kg/day IV or IM in 1 dose |
Oral Streptococci & S. gallolyticus β Penicillin-Susceptible
| Drug | Dose | Duration |
|---|---|---|
| Option a) | ||
| Penicillin G | 12β18 MU/day IV in 4β6 doses | 4 wks (NVE) or 6 wks (PVE) |
| Amoxicillin | 12 g/day IV in 4β6 doses | |
| Ceftriaxone | 2 g/day IV in 1 dose | |
| Option b) β 2-week course (non-complicated NVE only) | ||
| Same as above + Gentamicin | 3 mg/kg/day IV/IM in 1 dose | 2 weeks |
| Option c) β Beta-lactam allergy | ||
| Vancomycin | 30 mg/kg/day IV in 2 doses | 4 wks (NVE) or 6 wks (PVE) |
Increased Exposure or Resistant to Penicillin
| Drug | Dose | Duration |
|---|---|---|
| Penicillin G / Amoxicillin / Ceftriaxone | 24 MU/day; 12 g/day; 2 g/day | 4 wks NVE / 6 wks PVE |
| Plus Gentamicin | 3 mg/kg/day IV/IM in 1 dose | 2 weeks |
| Beta-lactam allergy | ||
| Vancomycin + Gentamicin | 30 mg/kg/day + 3 mg/kg/day | 4β6 wks + 2 wks |
S. pneumoniae / Ξ²-Haemolytic Streptococci (Groups A, B, C, G)
| Setting | Drug | Duration |
|---|---|---|
| 1) Absence of meningitis | ||
| Penicillin-susceptible | Penicillin G 12β18 MU/day or Ceftriaxone 2 g/day | 4 wks NVE / 6 wks PVE |
| Penicillin-resistant | Penicillin G / Ceftriaxone / Vancomycin 24 MU; 2 g; 30 mg/kg/day | 4 wks NVE / 6 wks PVE |
| 2) Presence of meningitis | ||
| Ceftriaxone 2 g q12h + Cefotaxime 2 g q4β6h + Vancomycin 30 mg/kg/day IV in 2 doses | 4 wks NVE / 6 wks PVE | |
Granulicatella & Abiotrophia
| Drug | Dose | Duration |
|---|---|---|
| Penicillin G / Ceftriaxone / Vancomycin | 12β18 MU; 12 g IV in 4β6 doses; 30 mg/kg/day | 6 weeks |
| Plus Gentamicin | 3 mg/kg/day IV/IM in 1 dose | 2 weeks |
MSSA (Methicillin-Susceptible)
| Setting | Drug | Dose | Duration |
|---|---|---|---|
| NVE | Cloxacillin or Cefazolin | 12 g/day in 4β6 doses; 6 g/day in 3 doses | 4β6 weeks |
| PVE | Cloxacillin/Cefazolin + Rifampin | 12 g/day + 900 mg/day in 3 doses; 6 g/day + 900 mg/day | 6 weeks |
| Plus | Gentamicin | 3 mg/kg/day in 1β2 doses | 2 weeks |
| Beta-Lactam Allergy | |||
| NVE | Cefazolin | 6 g/day in 3 doses | 4β6 weeks |
| PVE | Cefazolin + Rifampin + Gentamicin | 6 g/day + 900 mg/day + 3 mg/kg/day | 6 wks + 6 wks + 2 wks |
| Alternative if Beta-Lactam Allergy | |||
| NVE | Daptomycin + Ceftaroline or Fosfomycin | 10 mg/kg/day; 1800 mg/day; 8β12 g/day | 4β6 weeks |
| PVE | Daptomycin + Ceftaroline/Fosfomycin + Rifampin Β± Gentamicin | as above; 900 mg/day; 3 mg/kg/day | 6 wks; 2 wks |
MRSA (Methicillin-Resistant)
| Setting | Drug | Dose | Duration |
|---|---|---|---|
| NVE | Vancomycin | 30β60 mg/kg/day in 2β3 doses | 4β6 weeks |
| PVE | Vancomycin + Rifampin | 30β60 mg/kg/day + 900β1200 mg/day | 6 weeks |
| Plus | Gentamicin | 3 mg/kg/day in 1β2 doses | 2 weeks |
| Alternative (NVE) | |||
| NVE | Daptomycin + Cloxacillin/Ceftaroline/Fosfomycin | 10 mg/kg; 12 g/6 doses; 1800 mg/3 doses; 8β12 g/4 doses | 4β6 weeks |
| Setting | Drug | Dose | Duration |
|---|---|---|---|
| Beta-Lactam and Gentamicin-Susceptible | |||
| NVE/PVE | Ampicillin/Amoxicillin | 12 g/day IV in 4β6 doses | 6 weeks |
| Plus | Ceftriaxone OR Gentamicin | 4 g/day in 2 doses OR 3 mg/kg/day in 1 dose | 6 wks OR 2 wks |
| High-Level Aminoglycoside Resistance (HLAR) | |||
| NVE/PVE | Ampicillin/Amoxicillin + Ceftriaxone | 12 g/day + 4 g/day | 6 weeks each |
| Beta-Lactam Resistant (E. faecium) | |||
| Vancomycin + Gentamicin | 30 mg/kg/day + 3 mg/kg/day | 6 wks + 2 wks | |
| VRE | |||
| Daptomycin | 10β12 mg/kg/day IV in 1 dose | Individualized | |
| Plus | Ampicillin/Fosfomycin/Ceftaroline/Ertapenem | 12 g; 12 g in 4 doses; 1800 mg in 3 doses; 2 g in 1 dose | |
| Pathogen | Drug | Dose | Duration |
|---|---|---|---|
| Brucella spp. | Doxycycline + TMP-SMX + Rifampin | 200 mg/24h + 960 mg/12h + 300β600 mg/24h | β₯3β6 months PO |
| C. burnetii (Q fever) | Doxycycline + Hydroxychloroquine | 200 mg/24h + 200β600 mg/24h | >18 months PO |
| Bartonella spp. | Doxycycline + Gentamicin | 100 mg/12h PO + 3 mg/24h IV | 4 wks + 2 wks |
| Legionella spp. | Levofloxacin OR Clarithromycin + Rifampin | 500 mg/12h; 500 mg/12h; 300β1200 mg/24h | β₯6 wks or 2 wks then 4 wks |
| Mycoplasma spp. | Levofloxacin | 500 mg/12h IV or PO | β₯6 months |
| T. whipplei | Doxycycline + Hydroxychloroquine | 200 mg/24h + 200β600 mg/24h | >18 months PO |
References: ESC Guidelines 2023 for Management of Infective Endocarditis β UpToDate β AHA
12. Bone & Joint Infections
βΌ
Likely pathogens: S. aureus (MSSA/MRSA), Streptococci, aerobic GN bacilli.
| Drug | Dose |
|---|---|
| Anti-MRSA | |
| Vancomycin | 15β20 mg/kg IV q8β12h (target trough 15β20 Β΅g/mL) |
| Alternatives | |
| Daptomycin | 6β8 mg/kg IV q24h |
| Linezolid | 600 mg IV or PO q12h |
| Plus GN Coverage | |
| Ceftriaxone | 2 g IV q24h |
| Cefotaxime | 2 g IV q6β8h |
| Cefepime | 2 g IV q8β12h |
| Ceftazidime | 2 g IV q8h |
| Alternative GN Coverage | |
| Piperacillin-Tazobactam | 3.375β4.5 g IV q6β8h |
| Ciprofloxacin | 400 mg IV q12h |
Likely pathogens: S. aureus, Streptococci, Enterococci, GNB (Pseudomonas, Enterobacterales), Anaerobes.
| Drug | Dose |
|---|---|
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Plus | |
| Piperacillin-Tazobactam | 3.375β4.5 g IV q6β8h |
| Meropenem | 1 g IV q8h |
| Imipenem-Cilastatin | 500 mg q6h |
| Alternative | |
| Cefepime + Metronidazole | 2 g IV q8h + 500 mg IV/PO q8h |
Likely pathogens: Polymicrobial, coagulase-negative staphylococci, resistant GNB, Pseudomonas, Enterobacter.
| Drug | Dose |
|---|---|
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Plus | |
| Cefepime | 2 g IV q8h |
| Ceftazidime | 2 g IV q8h |
| Broader Coverage (Severe/Contaminated Wounds) | |
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Plus | |
| Piperacillin-Tazobactam | 3.375β4.5 g IV q6β8h |
| Meropenem | 1 g IV q8h |
| Imipenem-Cilastatin | 500 mg q6h |
β Note: If hardware is present: ADD Rifampin 300β450 mg PO q12h or 600 mg PO q24h. IMPORTANT: Rifampin must NOT be started empirically or during active bacteremia. It must be added ONLY AFTER initial IV therapy and confirmed susceptibility, due to high risk of resistance selection if used prematurely (IDSA PJI Guidelines 2013).
| Pathogen | Preferred Therapy | Alternative Therapy |
|---|---|---|
| S. aureus (MSSA) | Nafcillin/Oxacillin 2 g IV q4h or Cefazolin 2 g IV q8h | Ceftriaxone 2 g IV q24h; Clindamycin 600β900 mg IV q8h |
| S. aureus (MRSA) | Vancomycin 15β20 mg/kg IV q8β12h | Daptomycin 6β8 mg/kg q24h; Linezolid 600 mg q12h; Teicoplanin 12 mg/kg; Ceftaroline 600 mg q12h |
| Streptococci | Penicillin G 3β4 MU IV q4β6h or Ceftriaxone 2 g IV q24h | Cefazolin 2 g IV q8h; Vancomycin if allergic/resistant |
| Enterococci | Ampicillin 2 g IV q4h; Vancomycin if Amp-R | Daptomycin 6β8 mg/kg q24h (VRE); Linezolid; Teicoplanin |
| Enterobacterales | Ceftriaxone 2 g IV q24h; FQ if susceptible | Pip-tazo; Carbapenems for ESBL-producers |
| Pseudomonas | Cefepime/Ceftazidime 2 g q8h; Pip-tazo 4.5 g q6h | Meropenem 1 g q8h; Ciprofloxacin; Β± Aminoglycoside initially |
| Anaerobes | Metronidazole 500 mg q8h; Clindamycin 600β900 mg q8h | Pip-tazo; Carbapenems; Amox-clav (oral) |
Criteria for Oral Step-Down: Clinically stable and afebrile; CRP trending down; Adequate surgical debridement performed; No malabsorption or adherence concerns; Suitable highly bioavailable oral agent available based on susceptibility testing.
| Pathogen | Drug | Dose |
|---|---|---|
| MSSA | Cefadroxil / Levofloxacin | 500β1000 mg BID / 500β750 mg daily |
| MRSA | TMP-SMX / Doxycycline / Clindamycin / Linezolid | 1 DS BID / 100 mg BID / 600 mg TID / 600 mg BID |
| Gram-negative | Levofloxacin / Ciprofloxacin / TMP-SMX | 500β750 mg daily / 500β750 mg BID / 1 DS BID |
| Pen-sensitive Strep/Enterococcus | Amoxicillin / Clindamycin | 875β1000 mg TID / 300β450 mg TID |
Most commonly caused by S. aureus. Empiric therapy same as for hematogenous osteomyelitis. Pathogen-specific therapy: as per osteomyelitis tables above.
| Drug | Dose |
|---|---|
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Alternatives | |
| Daptomycin | 6β8 mg/kg IV q24h |
| Linezolid | 600 mg IV or PO q12h |
| Plus (Gram-negative coverage) | |
| Ceftriaxone | 2 g IV q24h |
| Cefotaxime | 2 g IV q6β8h |
| Cefepime | 2 g IV q8β12h |
| Ceftazidime | 2 g IV q8h |
| Alternative | |
| Piperacillin-Tazobactam | 3.375β4.5 g IV q6β8h |
| Ciprofloxacin | 400 mg IV q12h |
Oral Continuation Therapy (Retained Hardware Post-Debridement)
| Drug | Dose |
|---|---|
| First Line | |
| Levofloxacin | 500β750 mg daily |
| Ciprofloxacin | 500β750 mg BID |
| Alternative Regimens | |
| TMP-SMX | 1 DS tablet BID |
| Doxycycline | 100 mg BID |
| Cefadroxil | 500 mg BID |
| Cephalexin | 500 mg TID or QID |
| Plus (ALWAYS add for Staphylococcal PJI) | |
| Rifampin | 300β450 mg BID |
β Note: Rifampin must NOT be started empirically or during active bacteremia. Add ONLY after initial IV therapy phase and confirmed susceptibility (IDSA PJI Guidelines 2013).
Duration: 4β6 weeks
Antimicrobial Prescribing Policy
Hospital Antimicrobial Stewardship Program β’ Evidence-Based Antimicrobial Guidelines for Adult Patients
Drug Information Center β’ Dr. Marwa Ahmed | Dr. Heba Hassan | Dr. Ahmed Khaled
π
1. Community-Acquired Pneumonia (CAP)
βΌ
Treatment of CAP in adults who require hospitalization. Streptococcus pneumoniae and respiratory viruses are the most frequently detected pathogens.
| Drug | Dose |
|---|---|
| First Line | |
| Ceftriaxone | 1 to 2 g IV daily |
| Cefotaxime | 1 to 2 g IV every 8 hours |
| Ampicillin-Sulbactam | 3 g IV every 6 hours |
| Plus | |
| Azithromycin | 500 mg IV or orally daily |
| Clarithromycin | 500 mg twice daily |
| Alternative (Monotherapy) | |
| Levofloxacin | 750 mg IV or orally daily |
| Moxifloxacin | 400 mg IV or orally daily |
| Gemifloxacin | 320 mg orally daily |
| If Contraindications to Both Macrolides and Fluoroquinolones | |
| Beta-lactam + Doxycycline | 100 mg orally or IV twice daily |
Risk factors: Known Pseudomonas colonization/prior infection, GNR on sputum Gram stain, hospitalization with IV antibiotics in prior 3 months, long-term care, frequent COPD exacerbations, structural lung disease (bronchiectasis, CF), immunosuppression.
| Drug | Dose |
|---|---|
| Antipseudomonal Beta-Lactam (choose one) | |
| Piperacillin-Tazobactam | 4.5 g every 6 hours |
| Imipenem | 500 mg every 6 hours |
| Meropenem | 1 g every 8 hours |
| Cefepime | 2 g every 8 hours |
| Ceftazidime | 2 g every 8 hours |
| Plus (Fluoroquinolone) | |
| Ciprofloxacin | IV 400 mg every 8 hours |
| Levofloxacin | 750 mg daily |
Risk factors: Recent hospitalization/IV antibiotics in prior 3 months, recent influenza-like illness, necrotizing/cavitary pneumonia, empyema, known MRSA colonization/prior infection, GPC in clusters on sputum Gram stain.
ADD to the above regimen:
| Drug | Dose |
|---|---|
| Vancomycin | (15β20) mg/kg q12h |
| Linezolid | 600 mg q12h |
| Drug | Dose |
|---|---|
| Beta-Lactam (choose one) | |
| Ceftriaxone | 1 to 2 g IV daily |
| Cefotaxime | 1 to 2 g IV every 8 hours |
| Ampicillin-Sulbactam | 3 g IV every 6 hours |
| Ertapenem | 1 g IV daily |
| Plus | |
| Azithromycin | 500 mg IV or orally daily |
| Or | |
| Levofloxacin | 750 mg IV or orally daily |
| Moxifloxacin | 400 mg IV or orally daily |
Severe ICU-CAP with suspected MRSA/Pseudomonas requires a distinct regimen (not identical to ward management).
| Drug | Dose | Notes |
|---|---|---|
| Antipseudomonal Beta-Lactam (choose one) | ||
| Piperacillin-Tazobactam | 4.5 g every 6 hours | |
| Cefepime | 2 g every 8 hours | |
| Ceftazidime | 2 g every 8 hours | |
| Imipenem | 500 mg every 6 hours | |
| Meropenem | 1 g every 8 hours | |
| Plus Anti-MRSA Agent (if MRSA suspected) | ||
| Vancomycin | (15β20) mg/kg q12h | |
| Linezolid | 600 mg q12h | |
| Plus (Macrolide or Respiratory FQ) | ||
| Azithromycin | 500 mg IV daily | Preferred for atypical coverage |
| Levofloxacin | 750 mg IV daily | Alternative |
| Moxifloxacin | 400 mg IV daily | Alternative |
References: ATS/IDSA CAP Guidelines 2019 β UpToDate
2. Hospital-Acquired Pneumonia (HAP) & Ventilator-Associated Pneumonia (VAP)
βΌ
Cause: Commonly MDROs like P. aeruginosa, Acinetobacter, and MRSA.
Severe HAP is defined as: need for IV vasopressors (septic shock) OR need for mechanical ventilation due to pneumonia.
| Drug | Dose |
|---|---|
| Anti-MRSA (choose one) | |
| Vancomycin | 15 to 20 mg/kg every 8 to 12 hours |
| Linezolid | 600 mg IV every 12 hours |
| Plus β a) History of Carbapenem-Resistant Pathogens | |
| Ceftazidime-Avibactam | 2.5 g IV every 8 hours |
| Alternative (if ceftazidime-avibactam unavailable): along with a carbapenem | |
| Colistin | Loading: 300β360 mg CBA Γ 1, then maintenance: 160β240 mg CBA/day Γ· q12h (adjust for CrCl) |
| Aztreonam | 2 g IV every 8 hours |
| Levofloxacin | 750 mg IV or orally daily |
| Ciprofloxacin | 400 mg IV every 8 hours or 750 mg orally every 12 hours |
| Plus β b) No History of Carbapenem-Resistant Pathogens | |
| Meropenem | 1 g IV every 8 hours |
| Imipenem-Cilastatin | 500 mg IV every 6 hours |
β Note: Colistin: Renal dose adjustment is MANDATORY to avoid nephrotoxicity. Always adjust based on CrCl.
| Drug | Dose |
|---|---|
| No Risk of MDR | |
| Piperacillin-Tazobactam | 4.5 g IV every 6 hours |
| Cefepime | 2 g IV every 8 hours |
| Plus, if Risk of MRSA (β₯20% MRSA isolates, unknown susceptibility, or prior MRSA colonization) | |
| Vancomycin | 15β20 mg/kg/(8β12h) IV |
| Linezolid | 600 mg q12h IV |
| Risk of MDR: a) History of Carbapenem-Resistant Pathogens | |
| Ceftazidime-Avibactam | 2.5 g IV every 8 hours |
| Alternative (if unavailable): along with a carbapenem | |
| Colistin | Loading: 300β360 mg CBA Γ 1, then 160β240 mg CBA/day Γ· q12h (adjust for CrCl) |
| Aztreonam | 2 g IV every 8 hours |
| Levofloxacin | 750 mg IV or orally daily |
| Ciprofloxacin | 400 mg IV every 8 hours or 750 mg orally every 12 hours |
| b) No History of Carbapenem-Resistant Pathogens | |
| Meropenem | 1 g IV every 8 hours |
| Imipenem-Cilastatin | 500 mg IV every 6 hours |
| Plus, if Risk of MRSA (β₯20% MRSA isolates, unknown susceptibility, or prior MRSA colonization) | |
| Vancomycin | 15β20 mg/kg/(8β12h) IV |
| Linezolid | 600 mg q12h IV |
MDR risk: susceptibility unknown, >10% GNB resistant to cefepime/piperacillin-tazobactam, MDR GNB colonization from respiratory tract or other site.
References: ATS/IDSA HAP-VAP Guidelines 2016 β UpToDate
3. Aspiration Pneumonia
βΌ
Community-acquired aspiration pneumonia requiring hospitalization.
| Drug | Dose |
|---|---|
| First Line | |
| Ampicillin-Sulbactam | 1.5 to 3 g IV every 6 hours |
| Alternative | |
| Ceftriaxone | 1 or 2 g daily |
| Cefotaxime | 1 or 2 g every 8 hours |
| Plus | |
| Metronidazole | IV 500 mg every 8 hours |
| Drug | Dose |
|---|---|
| Antipseudomonal Beta-Lactam (choose one) | |
| Piperacillin-Tazobactam | 4.5 g IV every 6 hours |
| Imipenem | 500 mg IV every 6 hours |
| Meropenem | 1 g IV every 8 hours |
| Plus: MRSA Coverage (if risk factors present) | |
| Vancomycin | (15β20) mg/kg q12h |
| Linezolid | 600 mg q12h |
MRSA risk factors: recent hospitalization/IV antibiotics in prior 3 months, recent influenza-like illness, necrotizing/cavitary pneumonia, empyema, known MRSA colonization/prior infection, GPC in clusters on sputum Gram stain.
Hospital-acquired aspiration pneumonia requires MDR-organism coverage (Pseudomonas, Acinetobacter, MRSA). Treat with an antipseudomonal beta-lactam Β± anti-MRSA agent Β± anaerobic coverage, as per HAP/VAP protocol (Section 3). Do NOT equate with community-acquired aspiration pneumonia.
References: ATS/IDSA HAP Guidelines 2016 β UpToDate
4. Urinary Tract Infection (UTI)
βΌ
Relevant uropathogens: primarily E. coli, but also other Enterobacterales, other GNB (including P. aeruginosa), staphylococci, enterococci.
1) Patients Without MDR Risk Factors β Start empiric antibiotic therapy without obtaining culture
| Drug | Dose | Duration | Notes |
|---|---|---|---|
| Nitrofurantoin | 100 mg PO BID | F: 5d / M: 7d | Avoid if CrCl <30 mL/min |
| TMP-SMX | 1 DS (160/800 mg) PO BID | F: 3d / M: 7d | Useful for males with concern for prostatitis |
| Fosfomycin | 3 g | Single dose | |
| Alternatives | |||
| Amoxicillin-Clavulanate | 500 mg BID | F: 5β7d / M: 7d | |
| Cefpodoxime | 100 mg BID | F: 5β7d / M: 7d | |
| Cefadroxil | 500 mg BID | F: 5β7d / M: 7d | |
| Fluoroquinolones (avoid if other options available due to serious adverse effects) | |||
| Ciprofloxacin | 250 mg BID or 500 mg ER daily | F: 3d / M: 5d | Useful for males with prostatitis concern |
| Levofloxacin | 250 mg daily | F: 3d / M: 5d | |
2) Patients With MDR Risk Factors β Obtain urine culture and start empiric therapy
MDR risk (any in prior 3 months): MDR GN urinary isolate, inpatient stay, use of FQ/TMP-SMX/broad-spectrum beta-lactam, travel to regions with high MDR rates.
| Drug | Dose | Duration |
|---|---|---|
| Nitrofurantoin | 100 mg PO BID | F: 5d / M: 7d |
| Fosfomycin | 3 g | Single dose |
Alternatives: Treat empirically with an oral agent initially avoided due to resistance concerns while awaiting culture/susceptibility. If concerns about treatment failure (underlying urologic or immunocompromising condition), treat with an initial parenteral agent as for complicated UTI.
Infection beyond the bladder. Features suggesting extension: fever (>37.7Β°C), chills/rigors, significant fatigue, flank pain, CVA tenderness, pelvic/perineal pain in males.
1) Hospitalized β Critical Illness or Urinary Tract Obstruction
| Drug | Dose | Duration |
|---|---|---|
| a) If ESBL Prevalence High or Uncertain | ||
| Imipenem | 500 mg IV q6h or 1 g IV q8h (3h infusion) | 5β7 days |
| Meropenem | 1 to 2 g IV q8h (3h infusion) | |
| Plus β Anti-MRSA | ||
| Vancomycin | 15β20 mg/kg IV q8β12h Β± loading dose | |
| Linezolid (Alt.) | IV or PO 600 mg q12h | |
| b) If ESBL Prevalence Low (<10%) β Select regimen based on individual MDR risk as per "Other Hospitalized Patients" | ||
2) Other Hospitalized Patients
| Drug | Dose | Notes |
|---|---|---|
| No MDR Risk | ||
| Ceftriaxone | 1 to 2 g IV once daily | |
| Alternatives | ||
| Levofloxacin | 500 to 750 mg IV or PO daily | |
| Ciprofloxacin | IV: 400 mg BID / PO: 500β750 mg BID / ER: 1000 mg daily | |
| MDR Risk | ||
| Piperacillin-Tazobactam | 3.375 g IV q6h or 4.5 g IV q8h | If prior ESBL UTI + severely ill: favor carbapenem. Add vancomycin (MRSA) or daptomycin/linezolid (VRE) if suspected. |
| Cefepime | 1 g IV q12h or 2 g IV q8β12h | |
| Imipenem | 500 mg IV q6h (3h infusion) | |
| Meropenem | 1 to 2 g IV q8h (3h infusion) | |
1. Asymptomatic Bacteriuria
Antibiotic options are the same as those used to treat cystitis.
2. Cystitis (Bladder Infection)
| Drug | Dose | Duration | Notes |
|---|---|---|---|
| Amoxicillin | 500 mg PO q8h or 875 mg PO q12h | 5β7 days | Resistance may limit utility for GN pathogens |
| Amoxicillin-Clavulanate | 500 mg PO q8h or 875 mg PO q12h | 5β7 days | |
| Cefpodoxime | 100 mg PO q12h | 5β7 days | |
| Cephalexin | 250β500 mg PO q6h | 5β7 days | |
| Nitrofurantoin | 100 mg PO q12h | 5β7 days | |
| TMP-SMX | 800/160 mg q12h | 5β7 days | Typically avoided during first trimester |
| Fosfomycin | 3 g PO | Single dose | Not for pyelonephritis (inadequate renal levels) |
3. Pyelonephritis
Features: flank pain, nausea/vomiting, fever >38Β°C, CVA tenderness Β± cystitis symptoms, confirmed by bacteriuria.
| Drug | Dose | Notes |
|---|---|---|
| First Line | ||
| Ceftriaxone | 1 to 2 g IV q24h | |
| Alternatives | ||
| Cefepime | 1 to 2 g IV q12h | For patients with risk for ceftriaxone-resistant organisms |
| Piperacillin-Tazobactam | 3.375 g IV q6h or 4.5 g IV q8h | |
| Meropenem | 1 g q8h (3h infusion); 2 g q8h for prior MDR isolates | Reserve for resistance/critical infection |
| Ertapenem | 1 g q24h | |
| Aztreonam | 1 g q8h | For patients who cannot use beta-lactam |
Treat Asymptomatic Bacteriuria ONLY if:
- Pregnant
- Patients undergoing TURP or other urologic procedures with anticipated mucosal bleeding
β Note: Per IDSA 2019 guidelines, routine treatment of ASB in kidney transplant recipients (including the first 6 months post-transplantation) is no longer recommended. This represents an update from prior guidelines.
1. Asymptomatic Candiduria
Removal of catheter/stent should be considered. Treat with antifungal ONLY if:
- Neutropenia
- Very low birth weight infants
- Urinary tract manipulation
- Transplant recipients/diabetes mellitus/immunosuppression
2. Symptomatic Candiduria
| Indication | Drug & Dose |
|---|---|
| Cystitis | Fluconazole oral 200 mg (3 mg/kg)/24h |
| Pyelonephritis | Fluconazole 200 to 400 mg (3β6 mg/kg)/24h |
References: UpToDate β IDSA β IDSA ASB Guidelines 2019 (Nicolle et al.)
5. Acute Cellulitis and Erysipelas in Adults & Skin Abscesses
βΌ
Beta-hemolytic streptococci cause most cases; cellulitis is sometimes caused by S. aureus.
| Drug | Dose |
|---|---|
| Broad-Spectrum Beta-Lactam (choose one) | |
| Cefepime | 2 g every 8 hours |
| Piperacillin-Tazobactam | 4.5 g every 6 hours |
| Meropenem | 1 g every 8 hours |
| Imipenem-Cilastatin | 500 mg q6h or 1 g q8h |
| Plus Anti-MRSA | |
| Vancomycin | 20β35 mg/kg LD, then 15β20 mg/kg IV q8β12h |
| Daptomycin | 4β6 mg/kg IV q24h |
| Alternative | |
| Linezolid | 600 mg every 12 hours |
| Oral Switch (once clinically improved) | |
| Dicloxacillin | 500 mg PO q6h |
| Cephalexin | 500 mg PO q6h |
| Cefadroxil | 500 mg PO q12h or 1 g PO daily |
| TMP-SMX | 2 DS tablets BID |
| Amoxicillin + Doxycycline | 875 mg q12h + 100 mg q12h |
| Linezolid (Alt.) | 600 mg q12h |
| Clindamycin (Alt.) | 450 mg q8h |
| Drug | Dose |
|---|---|
| Without Indication for MRSA Coverage | |
| Cefazolin | 1 to 2 g every 8 hours |
| Nafcillin | 1 to 2 g every 4 hours |
| Oxacillin | 1 to 2 g every 4 hours |
| Flucloxacillin | 2 g every 6 hours |
| Vancomycin (severe beta-lactam allergy) | 20β35 mg/kg LD, then 15β20 mg/kg IV q8β12h |
| With Indication for MRSA Coverage | |
| Vancomycin | 20β35 mg/kg LD, then 15β20 mg/kg IV q8β12h |
| Daptomycin | 4β6 mg/kg IV q24h |
| Alternative | |
| Linezolid | 600 mg every 12 hours |
| Oral Switch (once clinically improved) | |
| Dicloxacillin | 500 mg PO q6h |
| Cephalexin | 500 mg PO q6h |
| Cefadroxil | 500 mg PO q12h or 1 g PO daily |
| TMP-SMX | 2 DS tablets BID |
| Amoxicillin + Doxycycline | 875 mg q12h + 100 mg q12h |
| Linezolid (Alt.) | 600 mg q12h |
| Clindamycin (Alt.) | 450 mg q8h |
MRSA indications: systemic toxicity (fever >38Β°C, sustained tachycardia), purulent wound drainage, injection drug use, known MRSA colonization/infection.
Parenteral antibiotic regimens for higher risk patients, typically started prior to I&D.
| Drug | Dose |
|---|---|
| Parenteral | |
| Vancomycin | 20β35 mg/kg LD, then 15β20 mg/kg IV q8β12h |
| Daptomycin | 4β6 mg/kg IV q24h |
| Alternative | |
| Linezolid | 600 mg every 12 hours |
| Oral Switch | |
| TMP-SMX | 2 DS tablets BID |
| Doxycycline | 100 mg PO BID |
| Clindamycin | 450 mg PO q8h |
Special Populations: Patients with severe illness, certain comorbidities, or atypical infection locations: treat as suggested for cellulitis.
References: UpToDate β IDSA Practice Guideline: Skin and Soft Tissue Infections
6. Necrotizing Fasciitis
βΌ
Caused by GAS, S. aureus, E. coli, Klebsiella, Clostridium, Aeromonas hydrophila.
| Drug | Dose |
|---|---|
| Broad-Spectrum (choose one) | |
| Imipenem | 1 g IV every 6 to 8 hours |
| Meropenem | 1 g IV every 8 hours |
| Piperacillin-Tazobactam | 3.375 g q6h or 4.5 g q8h |
| Plus Anti-MRSA (choose one) | |
| Vancomycin | 15β20 mg/kg/dose q8β12h |
| Daptomycin | 4β6 mg/kg IV once daily |
| Alternative to Vancomycin/Daptomycin | |
| Linezolid | 600 mg q12h |
| Plus (NOT with Linezolid) | |
| Clindamycin | 600 to 900 mg IV every 8 hours |
References: UpToDate β IDSA Practice Guideline: Skin and Soft Tissue Infections
7. Diabetic Foot Infections (DFIs)
βΌ
Patient systemically well and metabolically stable, with β₯1: cellulitis >2 cm, lymphangitic streaking, spread beneath superficial fascia, deep-tissue abscess, gangrene, or muscle/tendon/joint/bone involvement.
| Drug | Dose |
|---|---|
| Standard Coverage | |
| Ceftriaxone + Metronidazole | 2 g IV daily + 500 mg IV q8β12h |
| Ceftazidime + Metronidazole | 1β2 g q8h + 500 mg IV q8β12h |
| Cefepime + Metronidazole | 2 g q8β12h + 500 mg IV q8h |
| Ampicillin-Sulbactam | 3 g every 6 hours |
| Piperacillin-Tazobactam | 3.375 g IV q6h |
| If Indication for Pseudomonas Coverage | |
| Cefepime + Metronidazole | 2 g q8β12h + 500 mg IV q8h |
| Piperacillin-Tazobactam | 4.5 g IV q6h |
| Meropenem | 1 g every 8 hours |
| Imipenem-Cilastatin | 500 mg every 6 hours |
| If Indication for MRSA Coverage β ADD | |
| Vancomycin | 15β20 mg/kg q8β12h |
| Linezolid | 600 mg q12h |
| Daptomycin | 4β6 mg/kg q24h |
Pseudomonas indications: superficial necrosis with moist/pus appearance, significant water exposure, warm tropical/subtropical exposure, or Pseudomonas from a deep specimen.
Patient with systemic toxicity or metabolic instability (fever, chills, tachycardia, hypotension, confusion, vomiting, leukocytosis, acidosis, severe hyperglycemia, or azotemia).
| Drug | Dose |
|---|---|
| Broad-Spectrum (choose one) | |
| Cefepime + Metronidazole | 2 g q8β12h + 500 mg IV q8h |
| Piperacillin-Tazobactam | 4.5 g IV q6h |
| Meropenem | 1 g every 8 hours |
| Imipenem-Cilastatin | 500 mg every 6 hours |
| Plus Anti-MRSA (choose one) | |
| Vancomycin | 15β20 mg/kg q8β12h |
| Linezolid | 600 mg q12h |
| Daptomycin | 4β6 mg/kg q24h |
References: IDSA Practice Guideline β Diabetic Foot Infections
8. Intra-Abdominal Infections
βΌ
Most cases caused by enteric bacteria (E. coli, K. pneumoniae, E. faecalis, E. faecium).
1) Without Critical Illness or Risk of MDROs (Community-Acquired)
| Drug | Dose |
|---|---|
| Ceftriaxone | 2 g IV q24h |
| Cefotaxime | 2 g IV q8h |
| Alternatives | |
| Ciprofloxacin | 400 mg IV BID (not if on FQ prophylaxis) |
| Piperacillin-Tazobactam | 4.5 g IV q6h (non-critically ill with MDR GN risk) |
2) Critical Illness (Septic Shock) or Risk Factors for MDR GNB
MDRO risk: known colonization/prior MDRO infection, nosocomial SBP, recent hospitalization/beta-lactam use (prior 3 months), frequent healthcare contact.
| Drug | Dose |
|---|---|
| Carbapenem | |
| Meropenem | 1 g IV q8h |
| Imipenem-Cilastatin | 500 mg IV q6h |
| Plus: a) If Risk of MRSA | |
| Vancomycin | 15β20 mg/kg IV q8β12h |
| b) If Risk of VRE | |
| Daptomycin | 4β6 mg/kg IV q24h |
Predominant bacteria: coliforms (E. coli, Klebsiella, Proteus, Enterobacter), streptococci, enterococci, anaerobes.
Mildβmoderate (e.g., perforated appendix/appendiceal abscess) without resistance risk factors.
| Drug | Dose |
|---|---|
| Piperacillin-Tazobactam | 3.375 g IV q6h |
| Or: Metronidazole + one of the following | |
| Metronidazole | 500 mg IV or PO q8h |
| Plus | |
| Cefazolin | 1β2 g IV q8h |
| Ceftriaxone | 2 g IV daily |
| Cefotaxime | 2 g IV q8h |
| Ciprofloxacin | 400 mg IV q12h or 500 mg PO q12h |
| Levofloxacin | 750 mg IV or PO daily |
APACHE II >15 or β₯1 host/disease risk factor (age >70, immunocompromise, diffuse peritonitis, delay in source control >24h).
| Drug | Dose |
|---|---|
| Piperacillin-Tazobactam | 4.5 g IV q6h |
| Or | |
| Metronidazole | 500 mg IV or PO q8h |
| Plus | |
| Cefepime | 2 g IV q8h |
| Ceftazidime | 2 g IV q8h |
Onset >48h post-admission, hospitalization within 90 days, long-term care residence, or recent invasive therapy.
| Drug | Dose |
|---|---|
| Option 1 | |
| Imipenem-Cilastatin | 500 mg IV q6h |
| Meropenem | 1 g IV q8h |
| Piperacillin-Tazobactam | 4.5 g IV q6h |
| Or: Metronidazole + Antipseudomonal Cephalosporin | |
| Metronidazole | 500 mg IV or PO q8h |
| Plus | |
| Cefepime | 2 g IV q8h |
| Ceftazidime | 2 g IV q8h |
| Plus: If Risk of MRSA β ADD | |
| Vancomycin | 15β20 mg/kg IV q8β12h |
9. Catheter-Related Bloodstream Infection (CRBSI)
βΌ
Commonly caused by S. aureus or Candida species.
| Drug | Dose | Notes |
|---|---|---|
| 1. Anti-MRSA | ||
| Vancomycin (First line) | Loading: 20β30 mg/kg IV, then 15β20 mg/kg IV q8β12h | |
| Daptomycin (Alt.) | 8 to 10 mg/kg once daily | Also for units with high VRE rates |
| Linezolid | NOT appropriate for empiric CRBSI therapy | Linezolid is bacteriostatic (not bactericidal) β unsuitable for bacteremia/endovascular infections where bactericidal activity is essential |
| 2. Plus Antipseudomonal Beta-Lactam | ||
| Ceftazidime | 2 g every 8 hours | Extended/continuous infusion in critical illness or elevated MIC |
| Cefepime | 2 g every 8 hours | |
| Piperacillin-Tazobactam | 4.5 g every 6 hours | |
| Imipenem-Cilastatin | 500 mg q6h or 1 g q8h | |
| Meropenem | 1 to 2 g every 8 hours | |
| 3. Second Antipseudomonal (if hemodynamic instability, <90% local susceptibility, neutropenia, or MDR colonization) | ||
| Gentamicin | 5β7 mg/kg once daily | Should not be used as monotherapy |
| Amikacin | 15β30 mg/kg once daily | |
| Ciprofloxacin | 400 mg q8h | |
| 4. Antifungal (if risk factors: TPN, prolonged broad-spectrum ABs, hematologic malignancy, BMT/SOT, femoral catheter, multisite Candida colonization) | ||
| Caspofungin | 70 mg LD then 50 mg MD | |
| Fluconazole | Loading: 800 mg (12 mg/kg) day 1, then 400 mg daily (6 mg/kg/day) | If not critically ill; no azole exposure in prior 3 months |
References: UpToDate β IDSA CRBSI Guidelines 2009
10. CNS Infections
βΌ
Bacterial infections: S. pneumoniae, N. meningitidis.
| Drug | Dose |
|---|---|
| Ceftriaxone | 2 g IV q12h |
| Cefotaxime | 2 g IV q4β6h |
| Plus | |
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Plus (if age >50 years) | |
| Ampicillin | 2 g every 4 hours |
| Predisposing Factor | Drug | Dose |
|---|---|---|
| Head trauma / Basilar skull fracture | Vancomycin + Ceftriaxone OR Cefotaxime | 15β20 mg/kg q8β12h + 2 g q12h OR 2 g q4β6h |
| Penetrating trauma | Vancomycin + Cefepime OR Ceftazidime OR Meropenem | 15β20 mg/kg q8β12h + 2 g q8h |
| Post-neurosurgery | Vancomycin + Cefepime OR Ceftazidime OR Meropenem | 15β20 mg/kg q8β12h + 2 g q8h |
| CSF shunt | Vancomycin + Cefepime OR Ceftazidime OR Meropenem | 15β20 mg/kg q8β12h + 2 g q8h |
| Drug | Dose |
|---|---|
| Vancomycin | 15β20 mg/kg q8β12h |
| Plus | |
| Ampicillin | 2 g every 4 hours |
| Plus | |
| Cefepime | 2 g every 8 hours |
| or Meropenem | 2 g every 8 hours |
| Organism / Susceptibility | Standard Therapy | Alternative Therapies |
|---|---|---|
| Streptococcus pneumoniae | ||
| Penicillin MIC β€0.06 mcg/mL | Penicillin G or Ampicillin | 3rd-gen cephalosporin, Chloramphenicol |
| Pen β₯0.12 / Ceph MIC <1 mcg/mL | 3rd-gen cephalosporin | Cefepime, Meropenem |
| 3rd-gen cephalosporin MIC β₯1 mcg/mL | Vancomycin + 3rd-gen cephalosporin | Fluoroquinolone |
| Neisseria meningitidis | ||
| Penicillin MIC <0.1 mcg/mL | Penicillin G or Ampicillin | 3rd-gen cephalosporin, Chloramphenicol |
| 0.1 to 1.0 mcg/mL | 3rd-gen cephalosporin | FQ, Meropenem, Chloramphenicol |
| Other Organisms | ||
| Listeria monocytogenes | Ampicillin or Penicillin G | TMP-SMX |
| Group B Streptococcus | Ampicillin or Penicillin G | 3rd-gen cephalosporin |
| E. coli / Enterobacteriaceae | 3rd-gen cephalosporin | Aztreonam, FQ, Meropenem, TMP-SMX, Ampicillin |
| Pseudomonas aeruginosa | Cefepime or Ceftazidime | Aztreonam, Ciprofloxacin, Meropenem |
| Acinetobacter baumannii | Meropenem | Colistin or Polymyxin B |
| Haemophilus influenzae | ||
| Beta-lactamase negative | Ampicillin | 3rd-gen ceph, Cefepime, FQ, Aztreonam |
| Beta-lactamase positive | 3rd-gen cephalosporin | Cefepime, FQ, Aztreonam, Chloramphenicol |
| Staphylococcus aureus | ||
| Methicillin susceptible | Nafcillin or Oxacillin | Vancomycin, Meropenem, Linezolid, Daptomycin |
| Methicillin resistant | Vancomycin | TMP-SMX, Linezolid, Daptomycin |
| S. epidermidis | Vancomycin | Linezolid |
| Enterococcus species | ||
| Ampicillin susceptible | Ampicillin + Gentamicin | |
| Ampicillin resistant | Vancomycin + Gentamicin | |
| Ampicillin + Vancomycin resistant | Linezolid | |
Recommended IV doses for adults with bacterial meningitis and normal renal/hepatic function:
| Drug | Dose |
|---|---|
| Amikacin | 15β20 mg/kg/day (once daily or divided) |
| Ampicillin | 2 g every 4 hours |
| Aztreonam | 2 g every 6 to 8 hours |
| Cefepime | 2 g every 8 hours |
| Cefotaxime | 2 g every 4 to 6 hours |
| Ceftazidime | 2 g every 8 hours |
| Ceftriaxone | 2 g every 12 hours |
| Ciprofloxacin | 400 mg every 8 to 12 hours |
| Gentamicin | 1.7 mg/kg every 8 hours |
| Levofloxacin | 750 mg once daily |
| Meropenem | 2 g every 8 hours |
| Moxifloxacin | 400 mg every 24 hours |
| Nafcillin | 2 g IV every 4 hours |
| Oxacillin | 2 g IV every 4 hours |
| Rifampin | 600 mg every 24 hours |
| TMP-SMX | 5 mg/kg every 8 hours |
| Vancomycin | 15β20 mg/kg every 8 to 12 hours |
Primarily caused by Herpes Simplex Virus.
| Drug | Dose |
|---|---|
| Acyclovir | 10 mg/kg IV every 8 hours |
β CRITICAL: Acyclovir causes nephrotoxicity and neurotoxicity in renal impairment. Dose MUST be reduced based on CrCl (e.g., CrCl <25 mL/min: 10 mg/kg q24h). Use ideal or adjusted body weight for dosing in obesity to avoid overdosing.
References: IDSA β UpToDate β Lexicomp
11. Infective Endocarditis
βΌ
Native Valve Endocarditis (NVE)
| Drug | Dose |
|---|---|
| Vancomycin | 30 mg/kg/day IV in 2 doses |
| Plus | |
| Ceftriaxone | 2 g/day IV in 1 dose |
| Or Alternative | |
| Ampicillin-Sulbactam (if GI source risk) | 12 g/day IV in 4β6 doses |
| If Pseudomonas risk | |
| Piperacillin-Tazobactam | 4.5 g q6h |
| or Cefepime | 2 g q6h |
Prosthetic Valve Endocarditis (PVE)
| Drug | Dose |
|---|---|
| Vancomycin | 30 mg/kg/day IV in 2 doses |
| or Daptomycin | 10 mg/kg/day IV in 1 dose |
| Plus β if Pseudomonas risk | |
| Piperacillin-Tazobactam | 4.5 g q6h |
| or Cefepime | 2 g q6h |
| Plus (if healthcare-associated) | |
| Gentamicin | 3 mg/kg/day IV or IM in 1 dose |
Oral Streptococci & S. gallolyticus β Penicillin-Susceptible
| Drug | Dose | Duration |
|---|---|---|
| Option a) | ||
| Penicillin G | 12β18 MU/day IV in 4β6 doses | 4 wks (NVE) or 6 wks (PVE) |
| Amoxicillin | 12 g/day IV in 4β6 doses | |
| Ceftriaxone | 2 g/day IV in 1 dose | |
| Option b) β 2-week course (non-complicated NVE only) | ||
| Same as above + Gentamicin | 3 mg/kg/day IV/IM in 1 dose | 2 weeks |
| Option c) β Beta-lactam allergy | ||
| Vancomycin | 30 mg/kg/day IV in 2 doses | 4 wks (NVE) or 6 wks (PVE) |
Increased Exposure or Resistant to Penicillin
| Drug | Dose | Duration |
|---|---|---|
| Penicillin G / Amoxicillin / Ceftriaxone | 24 MU/day; 12 g/day; 2 g/day | 4 wks NVE / 6 wks PVE |
| Plus Gentamicin | 3 mg/kg/day IV/IM in 1 dose | 2 weeks |
| Beta-lactam allergy | ||
| Vancomycin + Gentamicin | 30 mg/kg/day + 3 mg/kg/day | 4β6 wks + 2 wks |
S. pneumoniae / Ξ²-Haemolytic Streptococci (Groups A, B, C, G)
| Setting | Drug | Duration |
|---|---|---|
| 1) Absence of meningitis | ||
| Penicillin-susceptible | Penicillin G 12β18 MU/day or Ceftriaxone 2 g/day | 4 wks NVE / 6 wks PVE |
| Penicillin-resistant | Penicillin G / Ceftriaxone / Vancomycin 24 MU; 2 g; 30 mg/kg/day | 4 wks NVE / 6 wks PVE |
| 2) Presence of meningitis | ||
| Ceftriaxone 2 g q12h + Cefotaxime 2 g q4β6h + Vancomycin 30 mg/kg/day IV in 2 doses | 4 wks NVE / 6 wks PVE | |
Granulicatella & Abiotrophia
| Drug | Dose | Duration |
|---|---|---|
| Penicillin G / Ceftriaxone / Vancomycin | 12β18 MU; 12 g IV in 4β6 doses; 30 mg/kg/day | 6 weeks |
| Plus Gentamicin | 3 mg/kg/day IV/IM in 1 dose | 2 weeks |
MSSA (Methicillin-Susceptible)
| Setting | Drug | Dose | Duration |
|---|---|---|---|
| NVE | Cloxacillin or Cefazolin | 12 g/day in 4β6 doses; 6 g/day in 3 doses | 4β6 weeks |
| PVE | Cloxacillin/Cefazolin + Rifampin | 12 g/day + 900 mg/day in 3 doses; 6 g/day + 900 mg/day | 6 weeks |
| Plus | Gentamicin | 3 mg/kg/day in 1β2 doses | 2 weeks |
| Beta-Lactam Allergy | |||
| NVE | Cefazolin | 6 g/day in 3 doses | 4β6 weeks |
| PVE | Cefazolin + Rifampin + Gentamicin | 6 g/day + 900 mg/day + 3 mg/kg/day | 6 wks + 6 wks + 2 wks |
| Alternative if Beta-Lactam Allergy | |||
| NVE | Daptomycin + Ceftaroline or Fosfomycin | 10 mg/kg/day; 1800 mg/day; 8β12 g/day | 4β6 weeks |
| PVE | Daptomycin + Ceftaroline/Fosfomycin + Rifampin Β± Gentamicin | as above; 900 mg/day; 3 mg/kg/day | 6 wks; 2 wks |
MRSA (Methicillin-Resistant)
| Setting | Drug | Dose | Duration |
|---|---|---|---|
| NVE | Vancomycin | 30β60 mg/kg/day in 2β3 doses | 4β6 weeks |
| PVE | Vancomycin + Rifampin | 30β60 mg/kg/day + 900β1200 mg/day | 6 weeks |
| Plus | Gentamicin | 3 mg/kg/day in 1β2 doses | 2 weeks |
| Alternative (NVE) | |||
| NVE | Daptomycin + Cloxacillin/Ceftaroline/Fosfomycin | 10 mg/kg; 12 g/6 doses; 1800 mg/3 doses; 8β12 g/4 doses | 4β6 weeks |
| Setting | Drug | Dose | Duration |
|---|---|---|---|
| Beta-Lactam and Gentamicin-Susceptible | |||
| NVE/PVE | Ampicillin/Amoxicillin | 12 g/day IV in 4β6 doses | 6 weeks |
| Plus | Ceftriaxone OR Gentamicin | 4 g/day in 2 doses OR 3 mg/kg/day in 1 dose | 6 wks OR 2 wks |
| High-Level Aminoglycoside Resistance (HLAR) | |||
| NVE/PVE | Ampicillin/Amoxicillin + Ceftriaxone | 12 g/day + 4 g/day | 6 weeks each |
| Beta-Lactam Resistant (E. faecium) | |||
| Vancomycin + Gentamicin | 30 mg/kg/day + 3 mg/kg/day | 6 wks + 2 wks | |
| VRE | |||
| Daptomycin | 10β12 mg/kg/day IV in 1 dose | Individualized | |
| Plus | Ampicillin/Fosfomycin/Ceftaroline/Ertapenem | 12 g; 12 g in 4 doses; 1800 mg in 3 doses; 2 g in 1 dose | |
| Pathogen | Drug | Dose | Duration |
|---|---|---|---|
| Brucella spp. | Doxycycline + TMP-SMX + Rifampin | 200 mg/24h + 960 mg/12h + 300β600 mg/24h | β₯3β6 months PO |
| C. burnetii (Q fever) | Doxycycline + Hydroxychloroquine | 200 mg/24h + 200β600 mg/24h | >18 months PO |
| Bartonella spp. | Doxycycline + Gentamicin | 100 mg/12h PO + 3 mg/24h IV | 4 wks + 2 wks |
| Legionella spp. | Levofloxacin OR Clarithromycin + Rifampin | 500 mg/12h; 500 mg/12h; 300β1200 mg/24h | β₯6 wks or 2 wks then 4 wks |
| Mycoplasma spp. | Levofloxacin | 500 mg/12h IV or PO | β₯6 months |
| T. whipplei | Doxycycline + Hydroxychloroquine | 200 mg/24h + 200β600 mg/24h | >18 months PO |
References: ESC Guidelines 2023 for Management of Infective Endocarditis β UpToDate β AHA
12. Bone & Joint Infections
βΌ
Likely pathogens: S. aureus (MSSA/MRSA), Streptococci, aerobic GN bacilli.
| Drug | Dose |
|---|---|
| Anti-MRSA | |
| Vancomycin | 15β20 mg/kg IV q8β12h (target trough 15β20 Β΅g/mL) |
| Alternatives | |
| Daptomycin | 6β8 mg/kg IV q24h |
| Linezolid | 600 mg IV or PO q12h |
| Plus GN Coverage | |
| Ceftriaxone | 2 g IV q24h |
| Cefotaxime | 2 g IV q6β8h |
| Cefepime | 2 g IV q8β12h |
| Ceftazidime | 2 g IV q8h |
| Alternative GN Coverage | |
| Piperacillin-Tazobactam | 3.375β4.5 g IV q6β8h |
| Ciprofloxacin | 400 mg IV q12h |
Likely pathogens: S. aureus, Streptococci, Enterococci, GNB (Pseudomonas, Enterobacterales), Anaerobes.
| Drug | Dose |
|---|---|
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Plus | |
| Piperacillin-Tazobactam | 3.375β4.5 g IV q6β8h |
| Meropenem | 1 g IV q8h |
| Imipenem-Cilastatin | 500 mg q6h |
| Alternative | |
| Cefepime + Metronidazole | 2 g IV q8h + 500 mg IV/PO q8h |
Likely pathogens: Polymicrobial, coagulase-negative staphylococci, resistant GNB, Pseudomonas, Enterobacter.
| Drug | Dose |
|---|---|
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Plus | |
| Cefepime | 2 g IV q8h |
| Ceftazidime | 2 g IV q8h |
| Broader Coverage (Severe/Contaminated Wounds) | |
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Plus | |
| Piperacillin-Tazobactam | 3.375β4.5 g IV q6β8h |
| Meropenem | 1 g IV q8h |
| Imipenem-Cilastatin | 500 mg q6h |
β Note: If hardware is present: ADD Rifampin 300β450 mg PO q12h or 600 mg PO q24h. IMPORTANT: Rifampin must NOT be started empirically or during active bacteremia. It must be added ONLY AFTER initial IV therapy and confirmed susceptibility, due to high risk of resistance selection if used prematurely (IDSA PJI Guidelines 2013).
| Pathogen | Preferred Therapy | Alternative Therapy |
|---|---|---|
| S. aureus (MSSA) | Nafcillin/Oxacillin 2 g IV q4h or Cefazolin 2 g IV q8h | Ceftriaxone 2 g IV q24h; Clindamycin 600β900 mg IV q8h |
| S. aureus (MRSA) | Vancomycin 15β20 mg/kg IV q8β12h | Daptomycin 6β8 mg/kg q24h; Linezolid 600 mg q12h; Teicoplanin 12 mg/kg; Ceftaroline 600 mg q12h |
| Streptococci | Penicillin G 3β4 MU IV q4β6h or Ceftriaxone 2 g IV q24h | Cefazolin 2 g IV q8h; Vancomycin if allergic/resistant |
| Enterococci | Ampicillin 2 g IV q4h; Vancomycin if Amp-R | Daptomycin 6β8 mg/kg q24h (VRE); Linezolid; Teicoplanin |
| Enterobacterales | Ceftriaxone 2 g IV q24h; FQ if susceptible | Pip-tazo; Carbapenems for ESBL-producers |
| Pseudomonas | Cefepime/Ceftazidime 2 g q8h; Pip-tazo 4.5 g q6h | Meropenem 1 g q8h; Ciprofloxacin; Β± Aminoglycoside initially |
| Anaerobes | Metronidazole 500 mg q8h; Clindamycin 600β900 mg q8h | Pip-tazo; Carbapenems; Amox-clav (oral) |
Criteria for Oral Step-Down: Clinically stable and afebrile; CRP trending down; Adequate surgical debridement performed; No malabsorption or adherence concerns; Suitable highly bioavailable oral agent available based on susceptibility testing.
| Pathogen | Drug | Dose |
|---|---|---|
| MSSA | Cefadroxil / Levofloxacin | 500β1000 mg BID / 500β750 mg daily |
| MRSA | TMP-SMX / Doxycycline / Clindamycin / Linezolid | 1 DS BID / 100 mg BID / 600 mg TID / 600 mg BID |
| Gram-negative | Levofloxacin / Ciprofloxacin / TMP-SMX | 500β750 mg daily / 500β750 mg BID / 1 DS BID |
| Pen-sensitive Strep/Enterococcus | Amoxicillin / Clindamycin | 875β1000 mg TID / 300β450 mg TID |
Most commonly caused by S. aureus. Empiric therapy same as for hematogenous osteomyelitis. Pathogen-specific therapy: as per osteomyelitis tables above.
| Drug | Dose |
|---|---|
| Vancomycin | 15β20 mg/kg IV q8β12h |
| Alternatives | |
| Daptomycin | 6β8 mg/kg IV q24h |
| Linezolid | 600 mg IV or PO q12h |
| Plus (Gram-negative coverage) | |
| Ceftriaxone | 2 g IV q24h |
| Cefotaxime | 2 g IV q6β8h |
| Cefepime | 2 g IV q8β12h |
| Ceftazidime | 2 g IV q8h |
| Alternative | |
| Piperacillin-Tazobactam | 3.375β4.5 g IV q6β8h |
| Ciprofloxacin | 400 mg IV q12h |
Oral Continuation Therapy (Retained Hardware Post-Debridement)
| Drug | Dose |
|---|---|
| First Line | |
| Levofloxacin | 500β750 mg daily |
| Ciprofloxacin | 500β750 mg BID |
| Alternative Regimens | |
| TMP-SMX | 1 DS tablet BID |
| Doxycycline | 100 mg BID |
| Cefadroxil | 500 mg BID |
| Cephalexin | 500 mg TID or QID |
| Plus (ALWAYS add for Staphylococcal PJI) | |
| Rifampin | 300β450 mg BID |
β Note: Rifampin must NOT be started empirically or during active bacteremia. Add ONLY after initial IV therapy phase and confirmed susceptibility (IDSA PJI Guidelines 2013).
Duration: 4β6 weeks