Microbial Etiology and Prognostic Factors of Ventilator-associated Pneumonia: A Multicenter Retrospective Study in Shanghai

Background: The microbial etiology and mortality risk factors of ventilator-associated pneumonia (VAP) have not been investigated extensively in Shanghai.

Methods: VAP cases were identified from the patients hospitalized during the period from 1 January 2013 to 30 December 2017 in Shanghai. The relevant data were reviewed and analyzed retrospectively.

Results: One hundred ninety-four VAP cases were included in this analysis. The overall mortality rate was 32.47%. The respiratory pathogens isolated from these patients included 212 bacterial strains and 54 fungal strains. The leading pathogens were Acinetobacter baumannii (33.96%), Klebsiella pneumoniae (23.58%), Pseudomonas aeruginosa (19.81%), and Staphylococcus aureus (7.08%). Candida colonization was associated with higher mortality of VAP patients compared to those without Candida colonization (45.45% vs 28.67%, P < .05). The VAP patients with Candida colonization also showed higher prevalence of P. aeruginosa, carbapenem-resistant P. aeruginosa (CRPA), K. pneumoniae, carbapenem-resistant K. pneumoniae (CRKP), A. baumannii, and carbapenem-resistant A. baumannii (CRAB) (P < .05). VAP nonsurvivors had higher prevalence of CRPA, K. pneumoniae, CRAB, and Candida than VAP survivors (P < .05). Multivariate analysis showed that prior antibiotic use was a significant risk factor for Candida colonization, while hypertension and length of hospital stay were significant risk factors of VAP mortality (P < .05).

Conclusions: The top pathogens of VAP patients in Shanghai tertiary teaching hospitals are A. baumannii, K. pneumoniae, and P. aeruginosa, with high prevalence of carbapenem resistance. Carbapenem-resistant bacterial pathogens and Candida may predict poor outcome.