Molecular characteristics and drug resistance of Aeromonas from environmental Sources in Ma'anshan, Anhui

ObjectiveTo understand the epidemiological characteristics, virulence gene characteristics and drug resistance of Aeromonas from environmental sources in Ma’anshan of Anhui province.

MethodsFrom January to December, 2017, Aeromonas strains isolated from seawater products, packaged foods, domestic water, swimming pool water and food poisoning samples in Ma'anshan were detected. The species of Aeromonas were identified through housekeeping gene rpoD sequence analysis. PCR was used to detect six virulence genes (Fla, Elastase, hlyA, ast, act and ascF-G), the molecular types of the strains were detected by using pulsed-field gel electrophoresis (PFGE), and drug susceptibility test of the strains was also conducted.

ResultsA total of 66 Aeromonas strains were isolated from 869 samples (7.6%), and the isolated rates were higher in rural domestic water, food poisoning samples and seafood products respectively. Sixty-six strains of Aeromonas belonged to seven species, mainly including A. veronii (24, 36.4%), A. hydrophila (13, 19.7%) and A. jandaei (13, 19.7%) respectively. 64 strains of Aeromonas (97.0%) carried one or more virulence genes, with the highest detection rate of Fla and act (53.1%), Fla was mainly detected in A. caviae (83.3%) and act was mainly detected in A. hydrophila (69.2%). Sixty six strains of Aeromonas were divided into 64 PFGE types, indicating the diversity of molecular biotypes. Drug susceptibility test showed that Aeromonas was sensitive to seven antibiotics including cefotetan, and partially sensitive to five antibiotics (1.5%–21.2%) such as cefazolin, and highly resistant to ampicillin and ampicillin/sulbactam (90.0%).

ConclusionThe contamination of Aeromonas, which carries multiple virulence genes and has high resistances to several antibiotics, is severe in Ma'anshan. It is necessary to strengthen the surveillance for Aeromonas and its drug resistance.