Carbapenem Resistance in Non-Fermentative Gram-Negative Bacilli Isolated from Intensive Care Unit Patients of a Referral Hospital.

Abstract

Non-fermentative Gram-negative bacilli or non-fermenters are opportunistic pathogens associated with serious infections in intensive care unit patients. Although carbapenems were considered as a backbone of treatment for life-threatening infections, these bacteria are increasingly acquiring resistance to carbapenems. Carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa are prioritized as critical pathogens by the World Health Organization. The objective of the study was to document the status of carbapenem-resistant and carbapenemase-producing non-fermenters isolated from intensive care unit patients. This study was conducted at Tribhuvan University Teaching Hospital, Kathmandu, Nepal. The clinical specimens collected from intensive care unit patients were processed for isolation and identification of non-fermenters and antibiotic susceptibility profile of bacterial isolates was determined. The multidrug-resistant isolates were identified and carbapenemase enzyme was detected in the carbapenem-resistant isolates. A total of 157 non-fermenters were isolated from 1063 samples which included Acinetobacter species (n=85), Pseudomonas aeruginosa (n=55), Burkholderia cepacia complex (n=15), and Stenotrophomonas maltophilia (n=2). Carbapenem resistance was reported in 85.9%, 72.7%, and 33.3% of Acinetobacter species, Pseudomonas aeruginosa, and Burkholderia cepacia complex, respectively. Among total non-fermenters, 91.1% isolates were multidrug-resistant and 60.8% carbapenem-resistant isolates were carbapenemase producers. The carbapenem-resistant isolates demonstrated an extremely high degree of resistance than carbapenem-susceptible isolates towards other antimicrobial classes. This study reported high rates of carbapenem-resistant, carbapenemase-producing, and multidrug-resistant non-fermenters isolates. Therefore, preventing the spread of these superbugs among the critically ill patients in intensive care units should be a major initiative in hospitals.