What pathogens does Zosyn (piperacillin/tazobactam) cover for pneumonia?

Zosyn (Piperacillin/Tazobactam) Coverage for Pneumonia

Zosyn (piperacillin/tazobactam) covers a broad spectrum of pathogens for pneumonia including beta-lactamase producing Haemophilus influenzae, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii, though Pseudomonas pneumonia should be treated in combination with an aminoglycoside. 1

Community-Acquired Pneumonia Coverage

For community-acquired pneumonia (CAP), Zosyn specifically covers:

• Beta-lactamase producing Haemophilus influenzae - FDA-approved indication for moderate severity community-acquired pneumonia 1
• Streptococcus pneumoniae (including drug-resistant strains)
• Staphylococcus aureus (methicillin-susceptible strains)
• Certain Enterobacteriaceae

Zosyn is typically not used as first-line therapy for uncomplicated community-acquired pneumonia but may be considered in more severe cases or when there are risk factors for resistant pathogens.

Hospital-Acquired/Nosocomial Pneumonia Coverage

For nosocomial pneumonia, Zosyn covers:

• Pseudomonas aeruginosa - but should be combined with an aminoglycoside 1
• Staphylococcus aureus (beta-lactamase producing isolates)
• Acinetobacter baumannii (susceptible strains)
• Klebsiella pneumoniae
• Haemophilus influenzae

The FDA label specifically states that for nosocomial pneumonia, Zosyn should be dosed at 4.5g every six hours plus an aminoglycoside when Pseudomonas aeruginosa is suspected or confirmed 1.

Aspiration Pneumonia Coverage

Zosyn also provides good coverage for aspiration pneumonia due to its activity against:

• Anaerobic bacteria commonly involved in aspiration
• Mixed aerobic-anaerobic infections

Research has shown Zosyn to be as effective as imipenem/cilastatin in treating moderate-to-severe aspiration pneumonia 2.

Important Clinical Considerations

1. For severe pneumonia/ICU patients:

   • Zosyn is recommended as one of the antipseudomonal β-lactams of choice 3
   • For patients with septic shock, combination therapy with Zosyn plus either a fluoroquinolone or aminoglycoside is recommended initially 3

2. Dosing considerations:

   • Community-acquired pneumonia: 3.375g IV every 6 hours 1
   • Nosocomial pneumonia: 4.5g IV every 6 hours plus an aminoglycoside 1
   • Renal dose adjustments required for creatinine clearance ≤40 mL/min 1

3. Duration of combination therapy:

   • If combination therapy is initially used for septic shock, de-escalation with discontinuation of combination therapy within the first few days is recommended if there is clinical improvement 3

4. Limitations of coverage:

   • Does not cover MRSA (requires addition of vancomycin or linezolid if MRSA is suspected) 3
   • May not be adequate for extended-spectrum beta-lactamase (ESBL) producing organisms depending on local susceptibilities 3

Zosyn's broad spectrum of activity makes it a valuable option for empiric therapy in both community-acquired and nosocomial pneumonia, particularly when resistant gram-negative pathogens are suspected.