Treatment Duration for Zerbaxa (Ceftolozane/Tazobactam) in HAP Caused by Pseudomonas
The IDSA/ATS 2016 guidelines recommend a 7-day course of antimicrobial therapy for hospital-acquired pneumonia (HAP), including cases caused by Pseudomonas species, regardless of the specific antibiotic used. 1
Standard Duration Recommendation
- For HAP, treat with Zerbaxa for 7 days (strong recommendation, very low-quality evidence). 1
- This 7-day duration applies to all HAP cases, including those caused by nonfermenting Gram-negative bacteria like Pseudomonas. 1
- The European guidelines (ERS/ESICM/ESCMID/ALAT 2017) similarly recommend 7-8 days for patients with good clinical response, specifically including nonfermenting Gram-negatives. 1
When to Extend Beyond 7 Days
Duration may need to be longer than 7 days if:
- The patient shows slow clinical improvement or lacks adequate response to therapy. 1
- Radiologic parameters are not improving appropriately. 1
- Laboratory parameters remain abnormal. 1
- The patient has immunodeficiency, cystic fibrosis, empyema, lung abscess, cavitation, or necrotizing pneumonia. 1
- Initial empiric therapy was inappropriate (i.e., organism was resistant to initial antibiotics). 1
Clinical Monitoring During Treatment
- Assess clinical stability criteria daily: temperature normalization, respiratory rate, oxygen saturation, mental status, and ability to take oral intake. 1
- Consider using procalcitonin (PCT) levels plus clinical criteria to guide discontinuation of therapy rather than relying on clinical criteria alone (weak recommendation, low-quality evidence). 1
- Do not use the Clinical Pulmonary Infection Score (CPIS) to guide discontinuation decisions. 1
Important Caveats
Note that Pseudomonas fluorescens is distinct from Pseudomonas aeruginosa. While the IDSA guidelines specifically address P. aeruginosa extensively, P. fluorescens is less commonly encountered and may have different susceptibility patterns. The 7-day duration recommendation applies broadly to Gram-negative HAP, but ensure susceptibility testing confirms ceftolozane/tazobactam activity against the specific isolate. 1
The ASPECT-NP trial, which established ceftolozane/tazobactam efficacy in nosocomial pneumonia, used 8-14 days of treatment, though this was a trial design choice rather than a minimum requirement. 2 Real-world evidence suggests clinical success rates of 72.6% with ceftolozane/tazobactam for drug-resistant Pseudomonas respiratory infections, though optimal duration remains incompletely defined. 3
De-escalation strategy: Consider narrowing from combination therapy to monotherapy with ceftolozane/tazobactam once susceptibilities are known and clinical improvement is documented (weak recommendation, very low-quality evidence). 1