AUTHOR=Xiang Guoxiu , Lan Kai , Cai Yimei , Liao Kang , Zhao Mei , Tao Jia , Ma Yi , Zeng Jianming , Zhang Weizheng , Wu Zhongwen , Yu Xuegao , Liu Yuyang , Lu Yang , Xu Caixia , Chen Liang , Tang Yi-Wei , Chen Cha , Jia Wei , Huang Bin 

TITLE=Clinical Molecular and Genomic Epidemiology of Morganella morganii in China

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.744291

DOI=10.3389/fmicb.2021.744291

ISSN=1664-302X

ABSTRACT=Objectives
Ongoing acquisition of antimicrobial resistance genes has made Morganella morganii a new clinical treatment challenge. Understanding the molecular epidemiology of M. morganii will contribute to clinical treatment and prevention.
Methods
We undertook a six-year clinical molecular epidemiological investigation of M. morganii from three tertiary hospitals in China since 2014. Antimicrobial susceptibility testing was performed using a VITEK-2 system. All isolates were screened for β-lactam and plasmid-mediated quino-lone resistance genes by PCR. Isolates carrying carbapenem-resistant genes were subjected to whole-genome sequencing (WGS). The variation and evolution of these mobile genetic ele-ments (MGEs) were then systematically analyzed.
Results
Among all M. morganii isolates (n=335), forty (11.9%) were recognized as multidrug resistant strains. qnrD1, aac(6')-Ib-cr, blaTEM-104 and blaCTX-M-162 were the top four most prevalent re-sistance genes. Notably, phylogenomic and population structure analysis suggested clade 1 (rhierBAPS SC3 and SC5) associated with multiple resistance genes seemed to be widely spread. WGS showed a blaOXA-181-carrying IncX3 plasmid and a Proteus genomic island 2 var-iant carrying blaCTX-M-3, aac(6')-Ib-cr coexisted in the same multidrug resistant strain zy_m28. Additionally, a blaIMP-1-carrying IncP-1β type plasmid was found in the strain nx_m63. 
Conclusions
This study indicates a clade of M. morganii is prone to acquire resistance genes, and multidrug resistant M. morganii are increasing by harboring a variety of MGEs including two newly dis-covered ones in the species. We should be vigilant that M. morganii may bring more extensive and challenging antimicrobial resistance issue.