Summary

The 2016 IDSA/ATS guideline addresses diagnosis and management of hospital-acquired pneumonia (HAP, non-ventilated) and ventilator-associated pneumonia (VAP) in adults, treating them as two distinct entities. Major changes from the 2005 version include adoption of GRADE methodology, elimination of the healthcare-associated pneumonia (HCAP) category, mandated use of local antibiograms to guide empiric therapy, 7-day treatment durations for most patients, and de-escalation strategies to limit unnecessary antibiotic use and resistance.

Key Recommendations

Diagnose VAP using noninvasive sampling (endotracheal aspirate) with semiquantitative cultures rather than bronchoscopic/invasive quantitative cultures.
Use clinical criteria alone—not PCT, sTREM-1, CRP, or CPIS—to decide whether to initiate antibiotic therapy for suspected HAP/VAP.
Do not treat ventilator-associated tracheobronchitis (VAT) with antibiotics.
Every hospital should generate a local ICU-specific antibiogram to guide empiric VAP/HAP therapy.
Empiric VAP regimens must cover S. aureus, P. aeruginosa, and other gram-negative bacilli; add MRSA coverage (vancomycin or linezolid) only if risk factors present, local MRSA prevalence >10–20%, or unknown.
Use two antipseudomonal agents from different classes empirically only when MDR risk factors are present, local gram-negative resistance >10%, or susceptibility data unavailable; otherwise use a single antipseudomonal agent.
Avoid aminoglycoside monotherapy for P. aeruginosa HAP/VAP; avoid aminoglycosides and colistin empirically if alternatives exist.
Treat MRSA HAP/VAP with vancomycin or linezolid; do not use tigecycline for Acinetobacter HAP/VAP.
For P. aeruginosa HAP/VAP, use monotherapy guided by susceptibility once known; use combination therapy only if patient remains in septic shock or at high mortality risk.
Treat both HAP and VAP for 7 days rather than longer courses, with duration individualized based on clinical response.
De-escalate empiric broad-spectrum therapy based on culture results rather than maintaining a fixed regimen.
Use PCT plus clinical criteria (not CPIS) to guide discontinuation of antibiotics; optimize dosing using PK/PD principles rather than package-insert dosing.

Thresholds & Doses

HAP definition: pneumonia ≥48 hours after admission, not ventilator-associated; VAP: pneumonia >48 hours after endotracheal intubation.
MRSA empiric coverage threshold: local S. aureus methicillin resistance >10–20% for VAP, >20% for HAP, or unknown prevalence.
Dual antipseudomonal coverage threshold: >10% of local gram-negatives resistant to candidate monotherapy agent.
MDR risk factor: IV antibiotics within prior 90 days (applies to MDR HAP, VAP, MRSA, and Pseudomonas).
Additional MDR VAP risk factors: ≥5 days hospitalization before VAP, septic shock at VAP onset, ARDS preceding VAP, acute RRT before VAP.
Invasive culture diagnostic thresholds: PSB <10³ CFU/mL or BAL <10⁴ CFU/mL → withhold antibiotics.
Vancomycin: 15 mg/kg IV q8–12h, trough 15–20 mg/mL; loading dose 25–30 mg/kg for severe illness.
Linezolid: 600 mg IV q12h.
Piperacillin-tazobactam: 4.5 g IV q6h (extended infusion appropriate).
Cefepime or ceftazidime: 2 g IV q8h.
Imipenem: 500 mg IV q6h (lower dose if <70 kg to prevent seizures); meropenem 1 g IV q8h.
Levofloxacin 750 mg IV daily; ciprofloxacin 400 mg IV q8h.
Amikacin 15–20 mg/kg IV q24h; gentamicin/tobramycin 5–7 mg/kg IV q24h.
Colistin: 5 mg/kg IV loading dose, then 2.5 × (1.5 × CrCl + 30) mg IV q12h; polymyxin B 2.5–3.0 mg/kg/day divided in 2 doses.
Aztreonam: 2 g IV q8h.
Duration of therapy: 7 days for both HAP and VAP.
VAT definition: fever, new/increased sputum, positive ETA culture >10⁶ CFU/mL, no radiographic pneumonia.

Citations

Executive Summary — key changes from 2005 guideline including GRADE, removal of HCAP, short-course therapy.
Section I — noninvasive semiquantitative culture preferred for VAP diagnosis.
Section X & Table 3 — empiric VAP antibiotic selection and doses.
Section XII & Table 4 — empiric HAP antibiotic regimens stratified by MRSA risk and mortality risk.
Table 2 — risk factors for MDR HAP/VAP, MRSA, and MDR Pseudomonas.
Sections XV–XX — pathogen-specific therapy (MRSA, P. aeruginosa, ESBL, Acinetobacter, carbapenem-resistant).
Sections XXI–XXII — 7-day duration of antibiotic therapy for VAP and HAP.
Sections XXIII–XXIV — de-escalation and PCT-guided discontinuation.