AUTHOR=Yang Lang , He Hong , Chen Qichao , Wang Kaiying , Lin Yanfeng , Li Peihan , Li Jinhui , Liu Xiong , Jia Leili , Song Hongbin , Li Peng 

TITLE=Nosocomial Outbreak of Carbapenemase-Producing Proteus mirabilis With Two Novel Salmonella Genomic Island 1 Variants Carrying Different blaNDM–1 Gene Copies in China

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 12 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.800938

DOI=10.3389/fmicb.2021.800938

ISSN=1664-302X

ABSTRACT=<p>NDM-1-producing multidrug-resistant <italic>Proteus mirabilis</italic> brings formidable clinical challenges. We report a nosocomial outbreak of carbapenem-resistant <italic>P. mirabilis</italic> in China. Six <italic>P. mirabilis</italic> strains collected in the same ward showed close phylogenetic relatedness, indicating clonal expansion. Illumina and MinION sequencing revealed that three isolates harbored a novel <italic>Salmonella</italic> genomic island 1 carrying a <italic>bla</italic><sub>NDM–1</sub> gene (SGI1-1NDM), while three other isolates showed elevated carbapenem resistance and carried a similar SGI1 but with two <italic>bla</italic><sub>NDM–1</sub> gene copies (SGI1-2NDM). Four new single nucleotide mutations were present in the genomes of the two-<italic>bla</italic><sub>NDM–1</sub>-harboring isolates, indicating later emergence of the SGI1-2NDM structure. Passage experiments indicated that both SGI variants were stably persistent in this clone without <italic>bla</italic><sub>NDM–1</sub> copy number changes. This study characterizes two novel <italic>bla</italic><sub>NDM–1</sub>-harboring SGI1 variants in <italic>P. mirabilis</italic> and provides a new insight into resistance gene copy number variation in bacteria.</p>