A mechanically ventilated ICU patient develops fever on day 5 with new bilateral infiltrates on chest X-ray. BAL is performed and cultures grow 10^5 CFU/mL of Pseudomonas aeruginosa. According to CDC/NHSN criteria, this is classified as:

• A Ventilator-associated pneumonia (VAP)
• B Possible VAP (PVAP) — a microbiologically confirmed VAE ✓
• C Ventilator-associated event (VAE) — infection-related ventilator-associated complication (IVAC)
• D Healthcare-associated pneumonia (HCAP) without VAP criteria

Explanation

Current CDC/NHSN surveillance uses a tiered ventilator-associated event (VAE) framework. After a ventilator-associated condition (VAC, defined by worsening oxygenation), if there is clinical evidence of infection (fever/leukocytosis + new antibiotics — IVAC criteria), microbiological confirmation via BAL culture ≥10^4 CFU/mL (or ≥10^5 for mini-BAL) qualifies the case as possible VAP (PVAP). The traditional clinical diagnosis of VAP (new infiltrates + purulent secretions + positive culture) is now termed clinically defined VAP in the clinical definition framework, separate from the surveillance definition of PVAP.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

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Written and medically reviewed by the StethoPrep medical team.