Phenotypic and genotypic distribution of ESBL, AmpC β-lactamase and carbapenemase-producing Enterobacteriaceae in community-acquired and hospital-acquired urinary tract infections in Sri Lanka.

Objectives: Although Sri Lanka belongs to a region with a high prevalence of extended-spectrum β-lactamase (ESBL), AmpC β-lactamase and carbapenemase-producing Enterobacteriaceae, data regarding antimicrobial resistance (AMR) is limited. We studied the prevalence and diversity of β-lactamases produced by Enterobacteriaceae urinary pathogens from two hospitals in the Western Province of Sri Lanka.

Methods: ESBL, AmpC β-lactamase and carbapenemase production was detected by phenotypic testing followed by genotyping.

Results: The species responsible for urinary tract infections (UTI) were Escherichia coli (69%), Klebsiella pneumoniae (16%) and Enterobacter sp (6%). The prevalence of ESBL (50%), AmpC β-lactamase (19%) and carbapenemase (11%) phenotypes was high, and greater in hospital-acquired (HA-UTI) (75%) than in community-acquired UTI (CA-UTI) (42%). Identification of CA-UTI caused by carbapenemase-producing Enterobacteriaceae (5%) is alarming. Only one ESBL gene, blaCTX- M-15, was detected. AmpC β-lactamase genes found in E. coli and K. pneumoniae were blaCMY-2, blaCMY-42 and blaDHA-1, while Enterobacter sp. carried blaACT-1. Carbapenemase genes were blaNDM-1, blaNDM-4, blaOXA-181 and blaOXA-232, while blaKPC, blaIMP and blaVIM were absent. Co-occurrence of multiple bla genes, with some isolates harbouring six different bla genes, was common. Carbapenem-resistant isolates without carbapenemase genes displayed mutations in the outer membrane porin genes, ompF of E. coli and ompK36 of K. pneumoniae. Factors associated with UTI with β-lactamase-producing Enterobacteriaceae were age ≥50 years, previous hospitalization, presence of an indwelling urinary catheter, history of diabetes mellitus or other chronic illness and recurrent urinary tract infections.

Conclusion: This study adds to the currently scarce data on AMR in Sri Lanka.