What infections does Zosyn (piperacillin/tazobactam) treat?

What Zosyn (Piperacillin/Tazobactam) Treats

Zosyn is FDA-approved for treating intra-abdominal infections, nosocomial pneumonia, skin and skin structure infections, female pelvic infections, and community-acquired pneumonia caused by beta-lactamase-producing bacteria. 1

FDA-Approved Indications

Intra-Abdominal Infections

• Appendicitis complicated by rupture or abscess and peritonitis caused by beta-lactamase-producing Escherichia coli or Bacteroides fragilis group organisms (B. fragilis, B. ovatus, B. thetaiotaomicron, B. vulgatus) 1
• Approved for adults and pediatric patients 2 months and older 1
• Piperacillin/tazobactam is recommended as single-agent therapy without requiring metronidazole for intra-abdominal infections 2
• Guidelines support its use as monotherapy for mild-to-moderate complicated intra-abdominal infections 3

Nosocomial (Hospital-Acquired) Pneumonia

• Moderate to severe nosocomial pneumonia caused by beta-lactamase-producing Staphylococcus aureus, Acinetobacter baumannii, Haemophilus influenzae, Klebsiella pneumoniae, and Pseudomonas aeruginosa 1
• For P. aeruginosa pneumonia, must be combined with an aminoglycoside 1
• Dosing: 4.5g every 6 hours plus aminoglycoside for 7-14 days 1
• Combination with amikacin was significantly more effective than ceftazidime plus amikacin for ventilator-associated pneumonia 4

Skin and Soft Tissue Infections

• Uncomplicated and complicated skin/skin structure infections including cellulitis, cutaneous abscesses, and ischemic/diabetic foot infections caused by beta-lactamase-producing S. aureus 1
• Approved only for adults for this indication 1
• Guidelines recommend piperacillin/tazobactam for necrotizing fasciitis as part of broad empiric coverage (combined with vancomycin or linezolid) 3
• Effective for incisional surgical site infections of the intestinal or genitourinary tract 3
• Clinical cure rates of 76-93% demonstrated in skin/soft tissue infection trials 5, 6

Female Pelvic Infections

• Postpartum endometritis and pelvic inflammatory disease caused by beta-lactamase-producing E. coli 1
• Approved for adult patients only 1

Community-Acquired Pneumonia

• Moderate severity only caused by beta-lactamase-producing H. influenzae 1
• Not for severe community-acquired pneumonia 1

Guideline-Supported Uses Beyond FDA Label

Febrile Neutropenia

• Piperacillin/tazobactam plus aminoglycoside is recommended for empirical treatment of initial infections in neutropenic patients 3
• Significantly more effective than ceftazidime plus aminoglycoside for febrile neutropenia 4, 7
• Particularly useful given current prevalence of Gram-positive infections in this population 4

Healthcare-Associated and Nosocomial Infections in Cirrhosis

• Recommended for healthcare-associated cellulitis, pneumonia, and complicated urinary tract infections in cirrhotic patients 3
• Should be used in settings without high local prevalence of ESBL-producing Enterobacteriaceae 3

Spectrum of Activity

Organisms Covered

• Gram-positive aerobes: Beta-lactamase-producing S. aureus (methicillin-susceptible only), streptococci 1, 4
• Gram-negative aerobes: E. coli, K. pneumoniae, P. aeruginosa, H. influenzae, A. baumannii 1, 4
• Anaerobes: Bacteroides fragilis group and other anaerobes 1, 4
• Broad coverage of beta-lactamase-producing organisms including some extended-spectrum beta-lactamase (ESBL) producers 8, 7

Organisms NOT Covered

• Methicillin-resistant S. aureus (MRSA) - requires addition of vancomycin, linezolid, or daptomycin 3
• Enterococci - routine coverage discouraged for most intra-abdominal infections 3
• AmpC beta-lactamase-producing organisms (Enterobacter, Citrobacter, Serratia) 8, 7
• Carbapenem-resistant Enterobacteriaceae (CRE) 2

Critical Dosing Information

Standard Dosing (Non-Pneumonia)

• 3.375g every 6 hours (total 13.5g daily) for 7-10 days 1
• Administered by IV infusion over 30 minutes 1

Nosocomial Pneumonia Dosing

• 4.5g every 6 hours (total 18g daily) plus aminoglycoside for 7-14 days 1

Renal Impairment

• Dose reduction required when creatinine clearance ≤40 mL/min 1
• Adjustments needed for hemodialysis and peritoneal dialysis patients 1

Common Pitfalls to Avoid

• Do NOT use for MRSA infections without adding vancomycin or alternative MRSA-active agent 3
• Do NOT combine with another beta-lactam (like ceftazidime) - provides no mechanistic advantage; use beta-lactam plus aminoglycoside for synergy instead 2
• Do NOT use as monotherapy for P. aeruginosa pneumonia - must add aminoglycoside 1
• Avoid prolonged use in settings with high ESBL prevalence due to selective pressure for resistant organisms 3, 2
• De-escalate to narrower therapy within 3-5 days once culture results available and clinical improvement evident 2