Antibiotic Resistance-Susceptibility Profiles of Enterococcus faecalis and Streptococcus spp. From the Human Vagina, and Genome Analysis of the Genetic Basis of Intrinsic and Acquired Resistances

Abstract

The spread of antibiotic resistance is a major public health concern worldwide. Commensal bacteria from the human genitourinary tract can act as reservoirs of resistance genes playing a role in their transfer to pathogens. In this study, the minimum inhibitory concentration of 16 antibiotics to 15 isolates from the human vagina, identified as Enterococcus faecalis, Streptococcus anginosus, and Streptococcus salivarius, was determined. Eight isolates were considered resistant to tetracycline, five to clindamycin and quinupristin-dalfopristin, and four to rifampicin. To investigate the presence of antimicrobial resistance genes, PCR analysis was performed in all isolates, and five were subjected to whole-genome sequencing analysis. PCR reactions identified tet(M) in all tetracycline-resistant E. faecalis isolates, while both tet(M) and tet(L) were found in tetracycline-resistant S. anginosus isolates. The tet(M) gene in E. faecalis VA02-2 was carried within an entire copy of the transposon Tn916. In S. anginosus VA01-10AN and VA01-14AN, the tet(M) and tet(L) genes were found contiguous with one another and flanked by genes encoding DNA mobilization and plasmid replication proteins. Amplification and sequencing suggested the lsaA gene to be complete in all E. faecalis isolates resistant to clindamycin and quinupristin-dalfopristin, while the gene contain mutations rendering to a non-functional LsaA in susceptible isolates. These results were subsequently confirmed by genome analysis of clindamycin and quinupristindalfopristin resistant and susceptible E. faecalis strains. Although a clinical breakpoint to kanamycin for S. salivarius has yet to be established, S. salivarius VA08-2AN showed an MIC to this antibiotic of 128 µg mL −1. However, genes involved in kanamycin resistance were not identified. Under the assayed conditions, neither tet(L) nor tet(M) from either E. faecalis or S. anginosus was transferred by conjugation to recipient strains

The Frequency of Class1 and 2 and 3 Integrons in Vancomycin-resistant and Aminoglycoside Resistance Enterococcus Strains Isolated From Burn Patients in Southwest Iran

“…Similar to our study, there have been extensive surveys in Iran and other countries (27)(28)(29). In a study conducted by Shahraki et al (2017), 182 samples were collected from the southeast of Iran.…”

Comprehensive Probiogenomics Analysis of the Commensal Escherichia Coli CEC15 as a Potential Probiotic Strain

“…Finally, EcN was found resistant to kanamycin, while CEC15 was sensitive. Even if the presence of AMR genes is far from being wanted, AMR genes are detected into the genome of many commensal, food and probiotic bacteria [68][69][70][71][72][73]. The presence of AMR genes is likely not a safety issue but can become when there is a risk of resistance transfer to other bacteria, notably to the human microbiota [64].…”

Biofilm Producing Enterococcus Isolates from Vaginal Microbiota

“…In a study done to look for the antimicrobial resistance pattern of the Enterococcus species from vaginal flora, minimum inhibitory concentration for different antibiotics was performed and all Enterococcus isolates were susceptible to gentamicin, streptomycin, ampicillin, penicillin, vancomycin, linezolid, erythromycin, and chloramphenicol. Among the E. faecalis isolates, there was less susceptibility seen in case of tetracycline, clindamycin, and quinupristin-dalfopristin [ 32 ].…”