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

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. <i>Escherichia coli</i>, 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 <i>E. coli</i> in caught rodents from Nakhon Si Thammarat province, Thailand. Captured rats were dissected to collect intestinal content for <i>E. coli</i> isolation. Two hundred and two confirmed <i>E. coli</i> were subjected for pathotype identification, antibiotic susceptibility testing, biofilm-forming ability (BFA), and the presence of related genes. Two <i>E. coli</i> isolates from intestinal content samples were atypical enteropathogenic (aEPEC). Predominantly, 52.97% of <i>E. coli</i> had azithromycin resistance, which was harbored by 35.64% of captured rats. Multidrug resistance (MDR) was found in 12.38% of <i>E. coli</i> isolates with 17 different MDR patterns. Remarkably, 96% of MDR isolates were resistant to azithromycin. Most <i>E. coli</i> harbored <i>ereA</i> (52%), followed by the <i>bla</i>_TEM and <i>aacC2</i> genes (6.44% each). Approximately 87% of isolated <i>E. coli</i> revealed moderate-to-high BFA. Predominantly, moderate-to-strong biofilm-forming <i>E. coli</i> harbored <i>pgaA</i> and <i>pgaC</i> genes. aEPEC, azithromycin resistance, MDR, and moderate-to-strong formation were the aspects of concern. Furthermore, the study of antibiotic-resistant <i>E. coli</i> 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.