Bacteriological profile of ventilator-associated pneumonia in a tertiary care hospital

Abstract

Background: Ventilator-associated pneumonia (VAP) is the most frequent intensive care unit (ICU)-acquired infection. The etiology of VAP and their antimicrobial susceptibility pattern varies with different patient populations and types of ICUs.

Materials and methods: An observational cross-sectional study was performed over a period of 2 years in a tertiary care hospital to determine the various etiological agents causing VAP and to detect the presence of multidrug-resistant (MDR) pathogens in these VAP patients. Combination disk method, Modified Hodge test, ethylenediaminetetraacetic acid disk synergy test, and AmpC disk test were performed for the detection of extended-spectrum beta-lactamase (ESBL), carbapenemases, metallo-beta-lactamases (MBL), and AmpC beta-lactamases, respectively.

Results: The prevalence of VAP was 35%. Enterobacteriaceae (66.66%) and Staphylococcus aureus (20%) were common in early-onset VAP, while nonfermenters (50%) and Enterobacteriaceae (40.61%) were predominant from late-onset VAP. Nearly 60.87% of the bacterial pathogens were MDR. ESBL was produced by 21.74% of Enterobacteriaceae. AmpC β-lactamase was positive in 35.29% nonfermenters and 26.08% Enterobacteriaceae. MBL was positive in 17.64% nonfermenters and 17.39% Enterobacteriaceae. Among the S. aureus isolates, 75% were cefoxitin resistant. Prior antibiotic therapy (P = 0.001) and hospitalization of 5 days or more (P = 0.001) were independent risk factors for VAP by MDR pathogens. polymyxin B, tigecycline, and vancomycin were the most sensitive drugs for Gram-negative and positive isolates respectively from VAP.

Statistical analysis: SPSS for Windows Version SPSS 17.0 (SPSS Inc., Chicago, IL, USA) and Chi-square with Yates correction.

Conclusion: Late-onset VAP is increasingly associated with MDR pathogens. Treatment with polymyxin B, tigecycline, and vancomycin should be kept as last-line reserve drugs against most of the MDR pathogens.

Keywords: Multidrug resistant; risk factors; ventilator-associated pneumonia.