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

Abstract

In this study, mechanisms of antimicrobial resistance (AR) as well as the abundance and diversity of plasmids were determined among multidrug resistant (MDR) enterococci from surface water in GA, USA. A total of 51 enterococci isolates were screened for the presence of 27 AR genes conferring resistance to ciprofloxacin, erythromycin, tylosin, kanamycin, streptomycin, lincomycin, Quinupristin/Dalfopristin (Q/D), and tetracycline. A plasmid classification system based on replication genes was used to detect 19 defined Gram-positive plasmid replicon families. Twelve genes were identified as conferring resistance to erythromycin and tylosin (erm(B) and erm(C)), kanamycin (aph(3′)-IIIa), streptomycin (ant(6)-Ia), lincomycin (lnu(B)), Q/D (vat(E)), ciprofloxacin (qnrE. faecalis), and tetracycline (tet(K), tet(L), tet(M), tet(O) and tet(S)). Twelve different rep-families were identified in two-thirds of the isolates. While AR genes commonly found in human and animals were detected in this study among environmental enterococci, resistance genes could not be determined for many of the isolates, which indicates that diverse AR mechanisms exist among enterococci, and the understanding of AR mechanisms for environmental enterococci is limited. Diverse rep-families were identified among the enterococci recovered from the aquatic environment, and these rep-families appear to be quite different from those recovered from other sources. This work expands knowledge of AR gene reservoirs and enterococcal plasmids across a wider range of environments.

Characterization and Comparison of Enterococcus spp. Isolates from Feces of Healthy Dogs and Urine of Dogs with UTIs

“…This could be related to the frequent use of this compound in pets therapy. The gene lnuB, conferring resistance to lincosamides and frequently carried by plasmids [51,52], was detected in relatively few isolates (21.6%), mainly E. faecalis, and it alone did not justify the detected level of resistance.…”

Occurrence of multidrug‐resistantEnterococcus faeciumisolated from environmental samples

“…Tetracycline resistance genes have been reported in a wide variety of bacteria, being genes encoding ribosomal protection (tetM and tetO) and efflux pumps (tetK and tetL) the most described in E. faecium (Miller et al 2014;Choi and Woo 2015;Cho et al 2020). Among the tet-like genes identified in E. faecium isolates, the tetM gene is the most prevalent being found within conjugative transposons of the Tn916/Tn1545 family (Cauwerts et al 2007;Molechan et al 2019).…”

“…2014; Choi and Woo 2015; Cho et al . 2020). Among the tet ‐like genes identified in E. faecium isolates, the tetM gene is the most prevalent being found within conjugative transposons of the Tn 916 /Tn 1545 family (Cauwerts et al .…”

“…In the clinical environment, E. faecium isolates producing the phenotypes known as high-level aminoglycoside resistance (HLAR) and high-level ciprofloxacin resistance (HLCR) have been increasingly described (Niu et al 2016;Ahmed and Baptiste 2018). Besides, E. faecium isolates resistant to different antimicrobial classes have already been described in farms and water sources, representing risks to public health (Roberts et al 2016;Tan et al 2018;Cho et al 2020). Therefore, considering the importance of this species in the One Health concept, this study aimed to characterize E. faecium isolates obtained from soil and water samples from distinct isolation sources regarding antimicrobial resistance and virulence determinants.…”

“…2018; Cho et al . 2020). Therefore, considering the importance of this species in the One Health concept, this study aimed to characterize E. faecium isolates obtained from soil and water samples from distinct isolation sources regarding antimicrobial resistance and virulence determinants.…”