Gram-Negative Bacteria and Antibiotic Resistances Isolated from Endotracheal Aspirate Samples of Patients Hospitalized in the Intensive Care Unit: 3-Years Retrospective Analysis

Abstract

Intensive care units (ICUs) are the most frequent department where hospital-acquired infections caused by multi-resistant microorganisms. Ventilator-associated pneumonia (VAP) is one of the most common serious infections in intensive care units with high mortality rate. In this study, it was aimed to determine the microorganisms and their antibiotic resistance rates of endotracheal aspirate (ETA) samples taken from patients who applied mechanical ventilation in our hospital's ICU. Gram negative microorganisms isolated from ETA samples sent from patients hospitalized at ICU between January 2016 and December 2018 were included in this study. For identification of the growing strains, matrix-mediated laser desorption ionization-flight time mass spectrometry (MALDI-TOF) (VITEK-MS, bioMérieux, France), VITEK 2 automated system (bioMérieux, France) were used to determine antibiotic susceptibility. The antibiotic susceptibility of the strains was evaluated according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. A total of 385 Gram negative microorganisms were isolated from ETA specimens with significant growth over the three-year period. When analyzing the distribution of microorganisms, A. baumannii (34.2%) was in the first place, followed by P. aeruginosa and K. pneumoniae. There was no significant difference in bacterial distribution in the three-year period. A. baumannii strains showed high levels of carbapenem resistance (94%), while the most effective antibiotics were colistin and tigecycline. Carbapenem and colistin resistance in P. aeruginosa strains were determined as 27% and 6.5%, respectively. Tigecycline was found to be the most effective antibiotic with 8% resistance rate in K. pneumoniae isolates. The high carbapenem resistance seen in A. baumannii strains isolated in our study is remarkable. Increased colistin resistance in K. pneumoniae shows that the last line drugs are also in danger. It is thought that following the antimicrobial resistance patterns of the ICU regularly, updating the treatment protocols in this direction and applying the infection control measures carefully will contribute to both the success of the treatment and the reduction of the resistance rates.

Keywords: Endotracheal aspirate, intensive care units, antibiotic resistance.

Special Issue of Health Sciences

DOI: 10.7176/JSTR/6-03-31