Objectives: The aim of this study was to determine the microorganisms causing ventilator-associated pneumonia (VAP) and investigate their antibiotic susceptibility. Methods: Patients diagnosed with VAP in the adult intensive care units (ICUs) between January 2015 and December 2018 were included in the study. VITEK 2 (bioMérieux, Marcy l’Etoile, France) automated microbiology system was used to identify microorganisms and to determine their antibiotic susceptibility. Results: Average VAP rates was found 26.51 per 1000 ventilator-days. A single microorganism was isolated in 104 of a total of 105 patients while two microorganisms were isolated in 1 patient. Of the isolated microorganisms, 94.3% (n=100) were Gram-negative bacteria and 5.7% (n=6) were Gram-positive bacteria. When the distribution of all microorganisms is examined in order of frequency, 62.2% were found to be Acinetobacter spp., 17.9% Pseudomonas spp., 6.6% Klebsiella pneumoniae, 4.7% Staphylococcus aureus, 3.7% Serratia marcescens, 2.8% Escherichia coli, 0.9% Enterococcus faecium, and 0.9% Stenotrophomonas maltophilia. The most effective antibiotics against Acinetobacter spp. were found to be colistin (96.9%), tigecycline (95%), amikacin (15%) and gentamicin (5%), whereas those the most effective against Pseudomonas spp. were found to be colistin (94.1%), ceftazidime (57.8%), gentamicin (55.5%), ciprofloxacin (50%), amikacin(50%), and piperacillin/tazobactam (42.1%). Conclusion: Acinetobacter spp. was the most common agent in VAP. The fact that Acinetobacter spp., which is resistant to carbapenems, quinolones, piperacillin-tazobactam and cephalosporins, was the most common agent in VAP, can significantly affect the mortality rate of the infection. Keywords: Antibiotic susceptibility, bacteria, intensive care unit, microorganism, ventilator-associated pneumonia
Corresponding Author: Unver E.