Acinetobacter baumannii producing ESBLs and carbapenemases in the Intensive Care Units developing fosfomycin and colistin resistance

Abstract

Acinetobacter baumannii is responsible for causing difficult-to-treat healthcare-associated infections globally, owing to its resistance to antibiotics. The intensive care unit (ICU) settings mediate spread of multidrug resistance (MDR) strains. This research aimed to evaluate non-susceptible colistin and fosfomycin A. baumannii, harboring extended-spectrum beta-lactamases (ESBLs) and carbapenemases in ICU setting. During the period of 2019-2021, this study obtained 200 A. baumanni isolates out of 1410 burns samples from an ICU setting. The antibiotic sensitivity, ESBLs and carbapenemase production were determined using clinical and laboratory standards institute (CLSI) 2020. The colistin (mcr-1 and mcr-2) and fosfomycin (fosA3) resistance genes was amplified. The highest resistance was to ceftazidime (98%), cefepime (86%), tetracycline (84%), levofloxacin (78%) and piperacillin-tazobactam (76%), while the highest sensitivity was to meropenem (63%) and tigecycline (62%). ESBL production was determined in 94% and carbapenemases were observed in 54% of A. baumannii. Four isolates (2%) were found to carry the mcr-1 gene, and three isolates (1.5%) were found to carry the mcr-2 gene. Moreover, the fosA3 was not detected in the isolates. This study showed that MDR A. baumannii was high in ICU settings. The spread of antibiotics considered the last line of defense against infections is a concern that necessitates surveillance and control measures.