Characterization of FosA13, a novel fosfomycin glutathione transferase identified in a Morganella morganii isolate from poultry

RunZhi Zhang ^1,2 Yan Yu ^2,3 Lulu Huang ⁴ Susu Chen ⁴ Ruxi Hu ⁴ Xiuxiu Wang ⁴ DaWei Huang ⁵ Chunhan Song ⁶ Junwan Lu ⁶ Qiyu Bao ^2,3,4,6 Yunliang Hu ^3* Pengfei Jiang ^1* Wei Pan ^5*

• ¹ Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou 325035, China., WenZhou, China
• ² Institute of Biomedical Informatics/School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou 325035, China., Wenzhou, Zhejiang Province, China
• ³ The Second Affiliated Hospital and Yuying Children’s Hospital, Wenzhou Medical University, Wenzhou 325027, China., Wenzhou, Zhejiang Province, China
• ⁴ Department of Laboratory Sciences, Pingyang Hospital of Wenzhou Medical University, Pingyang 325400, China., Wenzhou, China
• ⁵ Department of Laboratory Sciences, The People’s Hospital of Yuhuan, Yuhuan 317600, China., YuHuan，TaiZhou, China
• ⁶ Medical Molecular Biology Laboratory, School of Medicine, Jinhua University of Vocational Technology, Jinhua 321000, China., JinHua, China

Enterobacteriaceae. This species primarily causes infections of postoperative wounds and the urinary tract. Some isolates of M. morganii exhibit resistance to multiple antibiotics due to multidrug resistance traits, complicating clinical treatment; thus, there is a growing need to elucidate the resistance mechanisms of this pathogen.Methods: A total of 658 bacterial strains were isolated from anal fecal swabs from poultry and livestock and from the surrounding environment in Wenzhou, China, via plate streaking. The full genome sequences of the bacteria were obtained via nextgeneration sequencing platforms. The standard agar dilution method was employed to determine the minimum inhibitory concentrations (MICs) of various antimicrobial agents. The resistance gene (fosA13) of the isolate was identified using the Comprehensive Antibiotic Resistance Database (CARD) and confirmed via molecular cloning. The FosA13 protein encoded by the novel resistance gene fosA13 was expressed with the vector pCold I, and its enzyme kinetics parameters were characterized. The genetic background and evolutionary process of the sequence of this novel resistance gene were analyzed by means of bioinformatics methods.In this study, we identified a new chromosomally encoded fosfomycin resistance gene, designated fosA13, from the M. morganii isolate DW0548, which was isolated from poultry on a farm in Wenzhou, China. Compared with the control strain (pUCP19/DH5α), the recombinant strain carrying fosA13 (pUCP19-fosA13/DH5α) presented a fourfold increase in the MIC value for fosfomycin. The enzyme kinetics