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Xuan Liu,1,* Xin Li,1,* A-wen Yang,1 Bin Tang,1 Zi-juan Jian,1 Yi-ming Zhong,1 Hong-ling Li,1 Yan-ming Li,1 Qun Yan,1 Xiang-hui Liang,1,2 Wen-en Liu1,2 1Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan Province, People’s Republic of China; 2National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, Hunan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Wen-en Liu; Xiang-hui Liang, Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan Province, People’s Republic of China, Tel +86-731-84327437, Fax +86-731-84327332, Email wenenliu@163.com; 1677344146@qq.comBackground: Fecal carriage of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) and carbapenemase-producing E. coli (CP-EC) is well reported among hospitalized adults and children. However, there are few studies on the carriage prevalence and ESBL-EC and CP-EC genotypes among healthy children in China.Patients and Methods: Stool samples were collected from 330 students in 2021 from three randomly selected primary schools in Changsha, China. ESBL-EC and CP-EC were screened using CHROMagarTM chromogenic plates. ESBL and carbapenemase production was confirmed using the double-disc synergy test and a modified carbapenem inactivation method, respectively. Antimicrobial susceptibility was tested using the broth microdilution method. Resistance determinants, virulence factors, and phylogenetic groups were determined by PCR and sequencing. Multi-locus sequence typing (MLST) was performed (seven housekeeping genes were amplified and sequenced) on the phylogenic group B2 E. coli to detect high-risk clonal strains such as ST131 E. coli. Then, ST131 E. coli were characterized based on ST131 clades, O-type, and fimH alleles.Results: In total, 118 (35.8%) ESBL-EC and 3 (0.9%) CP-EC were isolated. blaCTX-M was the most common genotype (27.1%), identified in all ESBL-EC, except one, which carried blaSHV-12. One isolate with mcr-1 was found amongst ESBL-EC, whereas all three CP-EC carried blaNDM-1. The predominant sequence type (ST) clones in group B2 were ST131 and ST1193. The prevalence of ST131 E. coli was 9.9%, displaying serotypes O16 and O25b, fimH alleles 30, 41, and 89, and ST131 clades A and C1-M27.Conclusion: In this study, high carriage rate of ESBL-EC was found among healthy children, and the dominant ESBL was CTX-M-14. In addition, high-risk clones (ST131 and ST1193) were also detected. This emphasizes the importance of monitoring ESBL-EC in community settings.Keywords: community children, ESBL, CPE, ST131, mcr-1 |
