What is a recommended broad spectrum antibiotic for treating infections?

Broad Spectrum Antibiotic Recommendations

First-Line Broad Spectrum Options

For empiric treatment of serious infections requiring broad-spectrum coverage, piperacillin-tazobactam 3.375-4.5 grams IV every 6 hours is the preferred agent, providing comprehensive coverage against gram-positive, gram-negative (including Pseudomonas aeruginosa), and anaerobic pathogens. 1, 2

Alternative Broad Spectrum Agents

Carbapenems are equally effective broad-spectrum alternatives:

• Meropenem 1 gram IV every 8 hours provides excellent coverage for multidrug-resistant organisms and healthcare-associated infections 1
• Imipenem-cilastatin 500 mg IV every 6 hours or 1 gram every 8 hours offers similar spectrum 1
• Ertapenem 1 gram IV every 24 hours is appropriate for community-acquired infections but lacks Pseudomonas coverage 1

Ceftriaxone 1-2 grams IV every 12-24 hours is a third-generation cephalosporin with broad gram-negative and some gram-positive activity, though it is not adequate for MSSA infections (requires 2 grams twice daily for minimal effect) and should not be used as sole therapy for Pseudomonas 1, 3, 4, 5

Infection-Specific Recommendations

Intra-Abdominal Infections

• Piperacillin-tazobactam 3.375 grams IV every 6 hours is FDA-approved and highly effective 1, 2
• Alternative: Meropenem 1 gram IV every 8 hours or ceftriaxone 1-2 grams IV every 12-24 hours plus metronidazole 500 mg IV every 6-8 hours 1
• Duration: 5-7 days with adequate source control 1

Nosocomial Pneumonia

• Piperacillin-tazobactam 4.5 grams IV every 6 hours is the preferred regimen 2
• For Pseudomonas risk: Add gentamicin 5-7 mg/kg IV every 24 hours 1, 2
• Alternative: Ceftazidime 2 grams IV every 8 hours or cefepime 2 grams IV every 8-12 hours 1
• Duration: 7-14 days 2

Skin and Soft Tissue Infections

• Uncomplicated: Oral amoxicillin-clavulanate 875/125 mg twice daily covers MSSA and Streptococcus species 1, 6, 7
• Complicated/Severe: Piperacillin-tazobactam 3.375 grams IV every 6 hours 2
• Necrotizing infections: Vancomycin 15-20 mg/kg IV every 8-12 hours plus piperacillin-tazobactam or a carbapenem 1, 6

Sepsis/Septic Shock

• Initial empiric: Meropenem 1 gram IV every 8 hours or piperacillin-tazobactam 4.5 grams IV every 6 hours 1
• Add vancomycin 15-20 mg/kg IV every 8-12 hours if MRSA risk factors present (recent antibiotics, known colonization, injection drug use, healthcare exposure) 1, 6
• Consider echinocandin (anidulafungin, micafungin, or caspofungin) if Candida risk factors present 1

Pediatric Dosing

For children requiring broad-spectrum coverage:

• Piperacillin-tazobactam: 200-300 mg/kg/day IV divided every 6-8 hours (maximum 18 grams/day) 1
• Meropenem: 60 mg/kg/day IV divided every 8 hours 1
• Ceftriaxone: 80-100 mg/kg/day IV divided every 12-24 hours (maximum 4 grams/day) 1

Critical Considerations

Pseudomonas aeruginosa coverage requires:

• Antipseudomonal beta-lactam: piperacillin-tazobactam, ceftazidime, cefepime, or carbapenem (not ertapenem) 1
• Consider adding aminoglycoside for severe infections or septic shock 1, 2

MRSA coverage necessitates adding:

• Vancomycin 15-20 mg/kg IV every 8-12 hours (target trough 15-20 µg/mL) 1, 6
• Alternatives: Linezolid 600 mg IV every 12 hours or daptomycin 4-6 mg/kg IV every 24 hours 1

Anaerobic coverage is inherent with:

• Piperacillin-tazobactam, carbapenems, or beta-lactam/beta-lactamase inhibitor combinations 1
• If using ceftriaxone or fluoroquinolones, add metronidazole 500 mg IV every 6-8 hours 1

Common Pitfalls

• Ceftriaxone is inadequate for MSSA: Despite in vitro susceptibility, pharmacodynamic studies demonstrate poor bacterial killing even at 2 grams twice daily 5
• Ertapenem lacks Pseudomonas coverage: Do not use for nosocomial infections or when P. aeruginosa is suspected 1
• Monotherapy may be insufficient in septic shock: Combination therapy increases probability of adequate initial coverage for multidrug-resistant pathogens 1
• De-escalate based on cultures: Broad-spectrum agents should be narrowed once susceptibilities are available to reduce resistance and toxicity 1