Abstract
Salmonella Kentucky has become a global concern due to its invasiveness and rapid increase in antimicrobial resistance. It is an emerging human pathogen which has surfaced as a multidrug-resistant (MDR) clone, jeopardizing public’s health. Here, we have focused on the molecular characterisation of S. Kentucky isolated from clinical samples of children in India. S. Kentucky, isolated from the clinical samples of children from different hospitals in India during March 2017 to February 2024 were sent to the Gastro-Intestinal Tract Pathogen Repository of the ICMR-National Institute of Research in Bacterial Infections (NIRBI) for confirmation by serotyping. After confirmation, the isolates were investigated for antimicrobial susceptibility, antimicrobial resistance genes (ARGs), plasmid profiling, multilocus sequence typing (MLST) & pulsed-field gel electrophoresis (PFGE) subtypes. Whole genome sequencing (WGS) was performed for representative MDR S. Kentucky isolates. Among the 45 S. Kentucky isolates, higher resistance rates of 97.77%, 93.3%, 86.7%, 77.8% and 64.44% were observed for ciprofloxacin, ampicillin, tetracycline, norfloxacin and 3rd generation cephalosporins respectively. All isolates were susceptible to chloramphenicol and carbapenems. WGS revealed the presence of ESBL genes, bla(CTX−M−55), bla(CTX−M−15), bla(OXA−9) and multiple ARGs. Fluoroquinolone resistance was linked to mutations in gyrA (Ser83→Phe, Asp87→Tyr, ) and parC (Ser80→Iso) genes. Conjugative plasmid IncC and IncX4 harboring bla(CTX−M−15) and bla(CTX−M−55) respectively, were found in the study isolates. ST198 (n = 44) was found to be the predominant genotype by MLST. PFGE showed heterogeneous S. Kentucky strains in circulation. MDR S. Kentucky poses a potential health risk to the general public and alerts for the necessity of improved monitoring and investigation of this serovar by public health and food safety authorities. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42770-026-01950-8.