High-level resistance to gentamicin: genetic transfer between Enterococcus faecalis isolated from food of animal origin and human microbiota

Abstract

Aims: To investigate the in vivo gene transfer of high‐level gentamicin resistance (HLRG) from Enterococcus faecalis isolated from the food of animal origin to a human isolate, using a mouse model of intestinally colonized human microbiota. Methods and Results: In vitro study: The presence of plasmids involved in HLRG coding was investigated. After the conjugation experiment, the recipient strain, Ent. faecalis JH2‐SS, acquired a plasmid responsible for HLRG [minimal inhibitory concentration (MIC) >800 μg ml−1], in a similar position to the donor cells. In vivo study: Seven BALB/c mice were dosed with ceftriaxone (400 mg kg−1) and then inoculated with a dilution of 1/100 of human faeces (HFc). After 72 h, Ent. faecalis JH2‐SS (recipient) was inoculated and then, after a further 72 h, the animals were given Ent. faecalis CS19, isolated from the food of animal origin, involved in HLRG (donor). The presence of transconjugant strains in HFc was subsequently recorded on a daily basis until the end of the experiment. The clonal relationship between Ent. faecalis and Escherichia coli in faeces was assessed by RAPD‐PCR. Both the in vitro and in vivo studies showed that the receptor strain acquired a plasmid responsible for HLRG (MICs >800 μg ml−1), which migrated with a similar relative mobility value. Transconjugant strains were detected from 24 h after the donor strain inoculation and persisted until the end of the experiment. Conclusions: The in vivo gene transfer of HLRG from Ent. faecalis strains, isolated from the food of animal origin, to human microbiota has been demonstrated in a mouse model. Significance and Impact of the Study: The complexity found on the therapeutic responses of invasive infectious diseases caused by Ent. faecalis facilitates the assessment of food of animal origin as a resistant pathogen reservoir. In addition, this study may contribute to the understanding of antimicrobials’ resistance gene transfer between Ent. faecalis strains from food and human GI tract.

Clinical and microbiological features of bacteremia caused by Enterococcus faecalis

“…However, E. faecalis is the most common species causing invasive infections in hospitalized patients. The increasing incidence of enterococcal infections associated with healthcare is the result of a combination of bacterial features such as expression and transfer of genetic material, which increases their antimicrobial resistance and pathogenicity [4][5][6].…”

“…faecalis is prone to acquire resistance, possibly related to its ability to participate in various forms of conjugation, which can result in the spread of genes through conjugative transposons, pheromoneresponsive plasmids, or broad-host-range plasmids [6,10].…”

Köpek, Kedi ve İnsan Orijinli Enterococcus feacium İzolatlarının Biofilm Üretimi, Genotip ve Antibiyotik Direnç Profillerinin Belirlenmesi

“…Clinical cases involving VRE in companion animals are rare. Beside the several existing reports of VRE in animals [5] , there are a limited number of studies dealing with the colonization of VRE in companion animals [4] , even though VRE have been recorded in the intestinal tract of dogs and cats [6] . Simjee et al [22] described the isolation of a high-level gentamicin-resistant (HLGR) and vancomycinresistant E. faecium (VREfm) from a canine urinary tract infection in the USA, while Manson et al [23] isolated a gentamicin-sensitive VREfm from a canine in New Zealand.…”

“…Our results are in good agreement with previous reports in which RAPD was found to allow rapid identification of unknown isolates [8,11,17] . Antibiotic resistances have been reported to better define the links between animals and humans [6,18,19] . Cats and dogs have played an important role in the human community [20,21] , which allows them to have a good relationship with humans and contribute to their welfare; however, this relationship also poses serious risks of transmission of infectious agents to human [14] .…”

“…To differentiate the Enterococcus strains, various typing methods categorized into phenotypic and genotypic methods have been used in epidemiological studies in the past two decades. Antibiotyping of enterococci isolates by several methods were performed based on their different antibiotic resistance profiles [6] . Genotyping of Enterococcus species can be made by several methods such as random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) [3,7] .…”