가금류 분변에서 분리한 Extraintestinal Pathogenic Escherichia coli(ExPEC)의 특성 조사

Characterization of the Extraintestinal Pathogenic Escherichia coli(ExPEC) Isolates from the Fresh Poultry Feces

Extraintestinal pathogenic Escherichia coli (ExPEC) refers to pathogenic strains of E. coli capable of causing infections in extraintestinal sites of the host, including the urinary tract, bloodstream, lungs, and central nervous system. Among them, uropathogenic E. coli (UPEC) is recognized as a major etiological agent of urinary tract infections (UTIs) in humans and has been frequently isolated from poultry. The clinical significance of these isolates is associated with the presence of various virulence factor encoding genes such as aer (aerobactin), pap (P fimbriae), sfa (S fimbriae), afa1 (afimbrial adhesin I), and cnf1 (cytotoxic necrotizing factor 1). In this study, E. coli strains isolated from fresh feces of chickens and ducks were examined for the presence of UPEC-associated virulence genes using polymerase chain reaction (PCR) with both genomic and plasmid DNA templates. A total of 96 E. coli isolates were obtained from poultry fecal samples and screened for specific genes known to be associated with human urinary tract infections. The results revealed that aer, pap and sfa genes were detected in 67.7% (65 isolates), 89.6% (86 isolates), and 35.4% (34 isolates), respectively, while afa1 and cnf1 were not detected. In this study, E. coli strains isolated from fresh feces of chickens and ducks were examined for the presence of UPEC-associated virulence genes using polymerase chain reaction (PCR) with both genomic and plasmid DNA templates. A total of 96 E. coli isolates were obtained from poultry fecal samples and screened for specific genes known to be associated with human urinary tract infections. The results revealed that aer, pap and sfa genes were detected in 67.7% (65 isolates), 89.6% (86 isolates), and 35.4% (34 isolates), respectively, while afa1 and cnf1 were not detected. Examination of the gene location indicated that aer was primarily present on plasmid DNA rather than genomic DNA, whereas pap and sfa were found in both genomic and plasmid DNA in approximately equal proportions. Analysis of the number of virulence genes per isolate showed that only one isolate (1.1%) carried the aer gene alone, while 15 isolates (15.6%) carried only the pap gene. Thirty-seven isolates (38.5%) harbored both aer and pap, seven isolates (7.3%) carried pap and sfa simultaneously, and 27 isolates (28.1%) possessed aer, pap and sfa concurrently. These findings suggest that approximately 91% (87 isolates) of the isolates possessed at least one UPEC-associated virulence gene. This implies that poultry-derived E. coli strains may act as a potential reservoir for UPEC virulence factors, indicating a possible zoonotic risk and emphasizing the need for further attention from a public health perspective.