Isolation and genetic profiling of Yersinia enterocolitica strains from diarrheal samples of Iranian children under 5: PCR ribotyping insights.

Yersinia enterocolitica is a common pathogen between humans and animals and is one of the important bacterial pathogens causing gastrointestinal diseases worldwide. The aim of this study is to determine the prevalence of Y. enterocolitica in diarrhea of children under 5 years of age and to identify the isolates in terms of bioserotypes, virulence factors, antimicrobial sensitivity, and genetic diversity. During 2022-2023, 1092 diarrhea samples were collected from hospitals and analyzed to detect and isolate Y. enterocolitica. Biotype and serotype were determined by biochemical and agglutination methods. Six virulence genes were investigated by the PCR method. Antimicrobial resistance was tested by the disk diffusion method. Heterogeneity was done by the PCR ribotyping method. The prevalence of Y. enterocolitica was detected in 2.6 %. Bioserotypes 1A/O:8, 1A/O:NI, 1B/O:8 and 1B/O:NI were identified; most of the isolates were in the age group of less than one year. Abdominal pain and fever were the most common clinical symptoms in 1B/O:8. There was a significant relationship between the cold season and isolated bioserotypes (P = 0.0001). In biotype 1B isolates, the most common virulence genes were ystA, myfA, virF, ail, and inv; and in biotype 1A, ystB and inv. All isolates were sensitive to 14 antibiotics. Resistance to ampicillin was 100 %. High resistance to nitrofurantoin and ceftazidime was observed. Twenty-five isolates of Y. enterocolitica were analyzed by PCR ribotyping method, which identified 3 SR. The outbreak of highly pathogenic Y. enterocolitica 1B/O:8 in Iran may be a serious threat to the public health of Iran.