Virulence patterns and prevalence of seven Enterococcus species isolated from meats and leafy vegetables in South Korea

Abstract

This study examined the prevalence of seven species of Enterococcus in foodstuffs (n = 500) retailed in South Korea and identified the potential virulence of isolates. The overall detection rate of Enterococcus spp. was 68.2%, and the bacteria were most prevalent in refrigerated chicken (84.1%), followed by refrigerated pork (71.0%), frozen chicken (60.0%), leafy vegetables (56.0%), and refrigerated beef (53.0%). The prevalence differed by sample type: E. faecalis and E faecium were the most or second most frequently identified species in foods of animal origin, while a large portion of the leafy vegetable isolates were confirmed as E. casseliflavus. The presence of virulence genes was apparent in all species except E. durans; approximately half of the isolates (46.3%) had more than one virulence determinant, especially gelE (gelatinase) (88.1%). One of the interesting findings was that even non-E. faecalis and non-E. faecium enterococci also had virulence determinants. However, none of the Enterococcus isolates were resistant to vancomycin. These results provide comprehensive data on the prevalence of the genus Enterococcus in South Korea and empirical evidence regarding the virulence potential; thus, the findings herein call for further studies about the relevance of these bacteria to food safety.