Antimicrobial Resistance, Virulence Determinants, and Biofilm Formation of Enterococcus Species From Ready-to-Eat Seafood

Abstract

Enterococcus species form an important population of commensal bacteria and have been reported to possess numerous virulence factors considered significantly important in exacerbating diseases caused by them. The present study was designed to characterize antibiotic-resistant and virulent enterococci from ready-to-eat (RTE) seafood. A total of 720 RTE shrimp samples comprising sauced shrimp ( n = 288), boiled shrimp ( n = 216), and smoked shrimp ( n = 216) obtained from open markets in Delta State, Nigeria, were assessed. Standard classical methods and polymerase chain reaction (PCR) were used in identifying the Enterococcus species. Potential virulence factors (β-hemolysis, gelatinase activity, S-layer, and biofilm formation) were assessed using standard procedures. The antibiotic susceptibility profile of the identified enterococci isolates was assayed using the Kirby–Bauer disc diffusion method. PCR was further used to screen selected antibiotic resistance and virulence genes. Prevalence of Enterococcus species from shrimp varieties is as follows: sauced, 26 (9.03%); boiled, 6 (2.78%); and smoked, 27 (12.50%), with an overall prevalence of 59 (8.19%) based on the occurrence of black hallow colonies after incubation. Enterococcus species detected include E. faecalis , 17 (28.8%); E. faecium , 29 (49.2%); E. gallinarum , 6 (10.2%); E. casseliflavus , 2 (3.4%); E. hirae , 3 (5.1%); and E. durans , 2 (3.4%). Biofilm occurrence among the shrimp varieties is as follows: 19/26 (73.1%) for sauced shrimps, 5/6 (83.3%) for boiled shrimps, and 16/27 (59.3%) for smoked shrimps. The phenotypic expression of the enterococci virulence revealed the following: S-layer, 59 (100%); gelatinase production, 19 (32.2%); and β-hemolysis, 21 (35.6%). An average of 3–11 virulence genes were detected in the Enterococcus species. The resistance profile of Enterococcus species is as follows: erythromycin, 29 (49.2%); vancomycin, 22 (37.3%); and tetracycline, 27 (45.8%). The frequency of occurrence of antibiotic resistance genes from the phenotypic resistant enterococci isolates to the macrolide, glycopeptide, and tetracycline antibiotics is as follows: erm A, 13/29 (44.8%); van A, 14/22 (63.6%); tet A, 14/27 (51.9%); tet M, 15/27 (55.6%); erm B, 4/29 (13.8%); and van B, 5/22 (22.7%). Findings from this study reveal the antibiotic resistance of enterococci strains of such species as E. durans, E. casseliflavus, E. gallinarum , and E. hirae . This study further revealed that RTE food products are reservoirs of potential virul...

Antibiotic resistance in vancomycin‐resistant lactic acid bacteria (VRLAB) isolated from foods of animal origin

“…Other studies have shown that E. faecalis and E. faecium constitute the dominant flora in isolates obtained from animal‐originated foods (Cho et al, 2013; Jiménez et al, 2013; Morandi et al, 2015; Valenzuela, Benomar, Abriouel, Cañamero, & Gálvez, 2010; Yogurtcu & Tuncer, 2013). In contrast to our results, vancomycin‐resistant E. faecalis and/or E. faecium strains were isolated from animal‐originated foods in Slovakia (Kročko et al, 2011), Korea (Cho et al, 2013), Turkey (Çetinkaya et al, 2013), Spain (Guerrero‐Ramos et al, 2016), and Nigeria (Igbinosa & Beshiru, 2019). Pediococcus and Weissella can be isolated from animal‐originated foods as well as the commonly‐isolated Enterococcus species.…”

Antimicrobial Resistance Gene Detection and Plasmid Typing Among Multidrug Resistant Enterococci Isolated from Freshwater Environment

“…A similar finding could be seen among enterococcal isolates from animal and food sources [13,35,36]. Although resistance mechanisms for tetracycline and erythromycin were well understood and present among most of the enterococcal isolates across all species, AR genes could not be identified for many other antimicrobial drugs [13,35,36]. The genetic mechanisms of AR in non-faecalis and non-faecium enterococcal species seem to be quite different from those of E. faecalis and E. faecium, and the understanding of AR mechanisms needs to be improved for different species.…”

“…This could indicate that the genetic mechanism for tetracycline resistance is well understood, but not for other drug resistances. A similar finding could be seen among enterococcal isolates from animal and food sources [13,35,36]. Although resistance mechanisms for tetracycline and erythromycin were well understood and present among most of the enterococcal isolates across all species, AR genes could not be identified for many other antimicrobial drugs [13,35,36].…”

Antimicrobial Resistance, Virulence Genes, and Biofilm Formation Capacity Among Enterococcus species From Yaks in Aba Tibetan Autonomous Prefecture, China

“…As enterococci potentially transfer resistant genes from enteric bacteria in animals to humans via the food chain and they are potential pathogens, they have become a global public health concern. In previous reports, available data showed MDR Enterococcus with a variety of virulent determinants isolated from commensal animals, such as chickens, pigs and cattle (Diarra et al, 2010;Beshiru et al, 2017;De Jong et al, 2019;Igbinosa and Beshiru, 2019). However, there has been no available data on enterococci isolated from yaks.…”