Abstract

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a critical therapeutic challenge in hospitals of the Mekong Delta, Vietnam. Data on carbapenemase gene distribution and co-production of multiple genes at Can Tho remain limited.

Objectives: To determine the prevalence and distribution of carbapenemase genes by simplex PCR; to describe antimicrobial susceptibility profiles and analyze associations between resistance genotype and phenotype.

Methods: A cross-sectional descriptive study was conducted on 147 CRKP isolates at Can Tho University of Medicine and Pharmacy Hospital (November 2024–July 2025). Susceptibility testing was performed per CLSI M100 2024 (colistin per EUCAST 2024). Carbapenemase detection followed a two-step approach: mCIM for phenotypic screening, D73C disk test for enzyme classification, and simplex PCR confirmation for five genes (bla_OXA-48-like, bla_KPC, bla_NDM, bla_IMP, bla_VIM).

Results: All 147 isolates were multidrug-resistant (MDR, 100%), with extensively drug-resistant (XDR) at 56.5% and pandrug-resistant (PDR) at 8.0%. Colistin and tigecycline retained the highest susceptibility rates (98.6% and 98.0%, respectively). Carbapenemase production was detected in 57.1%: MBL 34.0%, OXA-48-like 19.0%, KPC 3.4%. Among 100 PCR-tested isolates, 84.0% carried at least one carbapenemase gene: bla_NDM predominated (71.1%), followed by bla_OXA-48-like (56.6%), bla_KPC and bla_VIM (7.2% each); bla_IMP was not detected. Co-production of multiple genes was identified in 34.0%, predominantly the bla_OXA-48-like + bla_NDM combination (82.4%). Agreement between D73C and PCR was good to very good: KPC (κ = 0.903), MBL (κ = 0.735), OXA-48-like (κ = 0.561), all p <0.001.

Conclusion: bla_NDM and bla_OXA-48-like were the predominant carbapenemase genes. The high co-production rate (34.0%) represents an important clinical warning. The mCIM → D73C → simplex PCR workflow demonstrated practical value for carbapenemase detection in clinical microbiology laboratories.