Interplay Between Phenotype and Genotype in Multidrug-Resistant and Hypervirulent Klebsiella pneumoniae Isolates From Southern Bangladesh.

Klebsiella pneumoniae (Kpn) is an opportunistic bacterium associated with various diseases, with significant morbidity and mortality due to treatment challenges posed by hypervirulent and multidrug-resistant (MDR) strains. This study investigates the prevalence of antimicrobial resistance, virulence factors, and clonal diversity of Kpn isolates. A total of 704 records were collected from the patient registries of two tertiary-care hospitals in Chattogram, Bangladesh. From these records, 123 biochemically confirmed clinical Klebsiella species were selected from admitted patients for molecular analysis. Antibiotic susceptibility, hypermucoid phenotype, and the presence of AMR genes (sul1, aadB) and the hypervirulence gene (rmpA) were determined. Whole-genome sequencing was also performed on one of the most drug-resistant isolates. Out of all isolates (n = 704), 72.59% were MDR, 18.89% DDR, and 7.95% DSDR. Among MDR, hospital-acquired infections (76%) were more prevalent than community-acquired infections (24%), with higher rates among geriatric (27%) and pediatric (25%) patients. The isolates showed high resistance to third-generation cephalosporins and the highest sensitivity to colistin. PCR analysis of the 81 phoE-positive isolates revealed that 85.18% carried the sul1 gene, while 6.17% harbored the aadB gene. Additionally, 12.34% were positive for the virulence gene rmpA, and 1.24% contained all three genes, sul1, aadB, and rmpA. Among the isolates, 65.43% were string test-positive. Notably, these string test-positive strains were resistant to most tested antibiotics compared to string test-negative strains. Whole-genome sequencing confirmed that KP-CU-1 as K. pneumoniae, with a 5.26 Mbp draft genome and an N50 of 164,530 bp, classified as sequence type 29 (ST29). This study indicates that MDR Kpn is highly prevalent, with a high proportion of hypervirulent strains. Establishing a nationwide AMR surveillance network will be essential to control the spread of MDR and hypervirulent Kpn in Bangladesh.