Bacteria isolated from endotracheal aspirates and their sensitivity pattern in patients suspected of ventilator associated pneumonia in a tertiary care hospital

Abstract

Background: Mechanically ventilated patients are at high risk of acquiring Ventilator Associated Pneumonia (VAP) due to complex interplay between the endotracheal tube, host immunity and virulence of invading bacteria. Knowledge about antimicrobial sensitivity patterns of VAP related microorganisms helps to start prompt and judicious antimicrobial treatment to combat the fatal consequences of VAP. Aim: To identify the antibiotic sensitivity patterns of the bacteria isolated from endotracheal aspirates of suspected VAP patients in ICU of a tertiary care hospital. Materials and Methods: It was a prospective observational study conducted in the adult ICU of Combined Military Hospital, Dhaka from January 2017 to December 2017. This study included the tracheal aspirates of 590 suspected VAP patients. Isolation of bacteria and their antibiotic sensitivity tests were done at Armed Forces Institute of Pathology (AFIP) according to CLSI guidelines. Results: Out of 590 samples, 198 showed significant growth that included 12 polymicrobial infections. Among 198 culture positive samples Klebsiella were the most predominant bacteria (41.90%) followed by Acinetobacter (35.71%), Pseudomonas (16.20%), Proteus (2.86%), Staphylococcus aureus (1.90%) and E. coli (1.43%). Colistin and tigecycline were highly effective against Klebsiella and Acinetobacter, but these isolates showed higher resistance against third and fourth generation cephalosporins and meropenem. Pseudomonas isolates were highly sensitive to carbenicillin, ticarcillin, piperacillin - tazobactam combination and colistin. Proteus isolates were fully sensitive to tigecycline and meropenem, but 100% resistant to colistin. Conclusion: Acinetobacter and Pseudomonas isolates showed more resistance pattern than other bacterial isolates. Colistin and tigecycline were found most effective antibiotics whereas commonly used antibiotics showed marked resistance pattern. The findings of this study will help in framing the appropriate antibiotic policy of the critical care centres of hospitals regarding the VAP related patients.