Biofilm formation and transfer of a streptomycin resistance gene in enterococci from fermented pork.
J Glob Antimicrob Resist. 2020 Apr 24;:
Authors: Chotinantakul K, Chansiw N, Okada S
OBJECTIVES: Multidrug-resistant (MDR) enterococci were found extensively in the food samples. This study characterized the phenotypic virulence factors and the ability of horizontal gene transfer of a streptomycin resistance gene among enterococci isolated from fermented pork.
METHODS: Thirty-six MDR enterococci were subjected to screening of gelatinase, biofilm formation at various temperatures (4, 25 and 37 °C), clumping ability and conjugation.
RESULTS: All positive-gelatinase and positive-clumping strains wereEnterococcus faecalis (41.7% and 38.9%, respectively). None of E. faecium and E. hirae demonstrated both phenotypes. Moderate and strong biofilm formations were found mostly at optimal temperature in all three species tested. However, moderate and weak biofilm formations could be found in 52.8% at 4 °C. The association between biofilm formation with asa1, efaA, gelE and esp genes was not observed. Surprisingly, our data revealed evidence of the streptomycin resistance gene (aadE) being transferred among meat E. faecalis isolates as characterized by the pheromone-clumping response.
CONCLUSIONS: Here we report the co-existence of some virulence factors and MDR enterococci from fermented pork. Our data demonstrated for the first time that theaadE gene could be transferred via conjugation among enterococci isolated from meat, contributing to streptomycin resistance. This study highlights the importance of horizontal gene transfer within the food chain reservoir and it might be possible for this to transfer to human, causing harm or untreated diseases.
PMID: 32339850 [PubMed - as supplied by publisher]