Antimicrobial susceptibility among aerobic bacteria isolates in the Intensive Care Unit of a tertiary regional hospital in Trinidad & Tobago.

Abstract

Background: There are variations in the epidemiology, prevalent pathogens and antimicrobial susceptibility patterns of infections in the intensive care unit (ICU) from one health care facility to another, hospital to hospital, and country to country. This study was undertaken to determine and document the frequency of occurrence of microbial isolates and their antibiotic susceptibility pattern from clinical specimens received from the ICU of a tertiary regional hospital in Trinidad and Tobago. Materials & methods: Microbial isolates from patients admitted to the ICU of the Eric Williams Medical Sciences Complex over a 4-year period were investigated. Automated systems and Standard microbiological methods including BACTEC 9240 (Becton-Dickinson Microbiology Systems), MicroScan Walk Away 96 SI (Dade Behring, USA), modified Kirby Bauer disc diffusion and Etest were used. Clinical specimens from 1,128 patients admitted to the ICU during the study period were processed, and 869 pathogens were recovered from 638 positive cultures. Results: The most frequent pathogens were recovered from respiratory tract specimens, while the Enterobacteriaceae groups of organisms were the most prevalent isolates. Except for Acinetobacter species that exhibit a consistent multiple drug resistant patterns, all the pathogens showed variable susceptibility to the readily available antimicrobials in the country. A 4.2% incidence rate of ESBL producers was encountered among the K. pneumoniae and E. coli isolates from the unit. Methicillin-resistant S. aureus was noted to be on the decline in this unit, but we observed the emergence of genuine vancomycin resistant methicillin-resistant S. aureus.Conclusions: Although Enterobacteriaceae and Pseudomonas aeruginosa were the most frequent isolates, there are still sufficient treatment options for patients infected with these organisms in the unit. Continuous surveillance and monitoring for multiple drug resistant pathogens in the unit should still be paramount especially with the ongoing establishment of the National Oncology Center and National Organ Transplant Units at the complex. There is an equal need for further studies on the determinants of drug resistance in this unit.