Detection of Antibiotic Resistance in Enterococci From Human Guts

We investigated the presence of antibiotic resistance genes in enterococci isolates that were obtained from faecal samples of 3 hospitalized patients receiving antibiotic prophylaxis therapy, and from ileostomy effluent of 1 subject without antibiotic dosage. 16S rRNA gene sequencing and (GTG)-5 PCR were used for classification of Enterococcus spp. Minimal Inhibitory Concentration (MIC) of vancomycin and double diffusion test for erythromycin resistance were determined. The carriage of vancomycin (vanA, vanB, vanC1, vanC2/C3, vanD, vanE and vanG) and erythromycin (ermA, ermB, ermC and mefA/E) resistance genes were investigated by PCR. Of 63 isolates (19 from faecal samples and 44 from ileostomy effluent), 13 (21%) were identified as E. faecium, 29 (46%) E. faecalis, 5 (8%) E. gallinarum and 16 (25%) E. avium. Only E. gallinarum and E. avium were found in ileostomy samples. A total of 59 isolates (94%) were resistant to vancomycin; however, only vanC1 gene was found in isolates (E. gallinarum). The phenotype found in all faecal isolates and in 13 (30%) of the ileostomy isolates corresponded to constitutive phenotype (cMLSb) erythromycin. ErmB genes were identified in 6 isolates from feces and 12 from ileostomy (E. avium and E. gallinarum). Additionally, these enterococci populations can be reservoirs for antibiotic resistance