Unraveling Antimicrobial Resistance Genes and Phenotype Patterns among Enterococcus faecalis Isolated from Retail Chicken Products in Japan

Abstract

Multidrug-resistant enterococci are considered crucial drivers for the dissemination of antimicrobial resistance determinants within and beyond a genus. These organisms may pass numerous resistance determinants to other harmful pathogens, whose multiple resistances would cause adverse consequences. Therefore, an understanding of the coexistence epidemiology of resistance genes is critical, but such information remains limited. In this study, our first objective was to determine the prevalence of principal resistance phenotypes and genes among Enterococcus faecalis isolated from retail chicken domestic products collected throughout Japan. Subsequent analysis of these data by using an additive Bayesian network (ABN) model revealed the co-appearance patterns of resistance genes and identified the associations between resistance genes and phenotypes. The common phenotypes observed among E. faecalis isolated from the domestic products were the resistances to oxytetracycline (58.4%), dihydrostreptomycin (50.4%), and erythromycin (37.2%), and the gene tet(L) was detected in 46.0% of the isolates. The ABN model identified statistically significant associations between tet(L) and erm(B), tet(L) and ant(6)-Ia, ant(6)-Ia and aph(3’)-IIIa, and aph(3’)-IIIa and erm(B), which indicated that a multiple-resistance profile of tetracycline, erythromycin, streptomycin, and kanamycin is systematic rather than random. Conversely, the presence of tet(O) was only negatively associated with that of erm(B) and tet(M), which suggested that in the presence of tet(O), the aforementioned multiple resistance is unlikely to be observed. Such heterogeneity in linkages among genes that confer the same phenotypic resistance highlights the importance of incorporating genetic information when investigating the risk factors for the spread of resistance. The epidemiological factors that underlie the persistence of systematic multiple-resistance patterns warrant further investigations with appropriate adjustments for ecological and bacteriological factors.

The unravelled Enterococcus faecalis zoonotic superbugs: Emerging multiple resistant and virulent lineages isolated from poultry environment

“…The proliferation and dissemination of MDR e.f have become important causes of zoonotic and nosocomial infections throughout the world (Hidano et al, ). In this study a, feed isolate, sensitive to most of antimicrobials suggest that, the antibiotic selective pressure during poultry production generously contributed for resistance acquisition.…”

“…The resistome exchange occurs usually by horizontal gene transfer (e.g. pathogenicity islands, transposons, plasmid exchange and/or mutation) due to antimicrobial selective pressure in humans, animals and livestock (Hidano et al, ). Evidently, E. faecalis is not only restricted to exchange of resistome, but it also reveals synergistic virulent interaction with E. coli (Seputiene, Bogdaite, Ruzauskas, & Suziedeliene, ).…”

Markov Networks of Collateral Resistance: National Antimicrobial Resistance Monitoring System Surveillance Results from Escherichia coli Isolates, 2004-2012

“…coli [22, 49, 62]. Directional edges represent types of causal relationships in the system they represent.…”

“…Directional edges represent types of causal relationships in the system they represent. In some cases, it is appropriate to assign directionality to AMR relationships, e.g., collateral resistance generated by in vitro selection for resistance to individual drugs [22] or the association between genes and phenotypical resistances [62]. In many other situations, including observational or surveillance studies of AMR where antimicrobial use is unknown, causality of an AMR relationship, if any exists, must be assumed [49].…”

High prevalence of vancomycin and high-level gentamicin resistance in Enterococcus faecalis isolates

“…Multiple drug-resistant enterococci are the major cause of healthcareassociated infections due to their virulence and antibiotic resistance traits [1][2][3][4]. They are considered as critical agent for the dissemination of antimicrobial resistance determinants to other bacteria through mobile genetic elements [2,5].…”