Molecular Epidemiological Characteristics of Carbapenem Resistant Aeromonas from Hospital Wastewater

Qianwen Zhang,1,* Shengcen Zhang,1,* Binbin Xu,1 Luyan Dong,1 Zhichang Zhao,2 Bin Li1 1Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fujian, 350001, People’s Republic of China; 2Department of Pharmacy, Fujian Medical University Union Hospital, Fuzhou, Fujian, People’s Republic of China*These authors contributed equally to this workCorrespondence: Bin Li, Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fujian, 350001, People’s Republic of China, Email leonlee307@hotmail.com Zhichang Zhao, Department of Pharmacy, Fujian Medical University Union Hospital, Fuzhou, Fujian, People’s Republic of China, Email slip2046@126.comBackground: Hospital wastewater (HWW) promotes the spread of carbapenem resistance genes (CRGs). Aeromonas carry a large number of CRGs in HWW, they may play a role as a suitable reservoir for CRGs, while resistomes in HWW are still poorly characterized regarding carbapenem resistant Aeromonas. Thus, the aim of the study was to evaluate the molecular epidemiological characteristics of carbapenem resistant Aeromonas in HWW.Methods: A total of 33 carbapenem resistant Aeromonas were isolated from HWW. Antimicrobial susceptibility testing and polymerase chain reaction (PCR) were used to assess the antimicrobial resistance profiles. Molecular typing was performed using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and multilocus sequence typing (MLST). The horizontal transmission mode of blaKPC was explored through conjugation and transformation experiments. The stability of blaKPC-IncP-6 plasmids was assessed through plasmid stability and in vitro competition test. The PCR mapping method was used to investigate the structural diversity of blaKPC.Results: The detection rates of blaKPC and cphA in Aeromonas were 97.0% and 39.4% respectively. Aeromonas caviae were grouped into 13 clusters by ERIC-PCR and 12 STs by MLST. Aeromonas veronii were grouped into 11 clusters by ERIC-PCR and 4 STs by MLST. 56.3% blaKPC were located on mobilizable IncP-6 plasmids. blaKPC-IncP-6 plasmid showed high stability and low cost fitness.Conclusion: Carbapenem resistant Aeromonas from HWW mainly carried blaKPC, which exhibited great structural diversity. Aeromonas might serve as reservoirs for blaKPC and blaKPC might spread mainly through transformation in HWW.Keywords: hospital wastewater, carbapenem resistance, Aeromonas, IncP-6, blaKPC