Rattus spp. as Reservoirs of Multidrug Resistance- and Biofilm-Forming Escherichia coli in Urban Community from Southern Thailand

Abstract

Rats are rodents commonly found in Thailand that carry various zoonotic pathogens. Bacterial zoonosis can occur in a shared environment between humans and rats, especially in human communities and agricultural areas. Escherichia coli, particularly pathogenic and multidrug-resistant strains, is a significant public health concern that is transmitted by rats. This study aimed to investigate the antibiotic resistance (ABR) and biofilm formation of E. coli in caught rodents from Nakhon Si Thammarat province, Thailand. Captured rats were dissected to collect intestinal content for E. coli isolation. Two hundred and two confirmed E. coli were subjected for pathotype identification, antibiotic susceptibility testing, biofilm-forming ability (BFA), and the presence of related genes. Two E. coli isolates from intestinal content samples were atypical enteropathogenic (aEPEC). Predominantly, 52.97% of E. coli had azithromycin resistance, which was harbored by 35.64% of captured rats. Multidrug resistance (MDR) was found in 12.38% of E. coli isolates with 17 different MDR patterns. Remarkably, 96% of MDR isolates were resistant to azithromycin. Most E. coli harbored ereA (52%), followed by the bla<inf>TEM</inf> and aacC2 genes (6.44% each). Approximately 87% of isolated E. coli revealed moderate-to-high BFA. Predominantly, moderate-to-strong biofilm-forming E. coli harbored pgaA and pgaC genes. aEPEC, azithromycin resistance, MDR, and moderate-to-strong formation were the aspects of concern. Furthermore, the study of antibiotic-resistant E. coli in rats should be performed, particularly in terms of the transmission pathway, and the application of rats as bioindicators for ABR surveillance in Thailand should be established.