Faecal carriage of high-level aminoglycoside-resistant and ampicillin-resistant Enterococcus species in healthy Iranian children.

Abstract

High-level aminoglycoside, ampicillin and vancomycin resistance and virulence genes among enterococcal isolates collected from healthy middle-school children in Ardabil, Iran, during 2016 were investigated. Totally, 305 faecal specimens were collected. Isolates underwent antimicrobial susceptibility testing, virulence gene detection and molecular typing. Totally, 409 enterococcal isolates were collected, comprising Enterococcus faecium (235; 57.5%), Enterococcus faecalis (56; 13.7%) and other Enterococcus spp. (118; 28.9%). Overall, 71 (17.4%), 11 (2.7%) and 10 (2.4%) isolates were identified as high-level streptomycin-resistant (HLSR), high-level gentamicin-resistant (HLGR) and ampicillin-resistant (AR), respectively. Among HLSR isolates, 40 (56.3%), 5 (7.0%) and 26 (36.6%) were E. faecium, E. faecalis and other Enterococcus spp., respectively. Among HLGR isolates 4 (36.4%) and 7 (63.6%) and among AR isolates 7 (70.0%) and 3 (30.0%) were E. faecium and other Enterococcus spp., respectively. Accordingly, 21.6%, 3.6% and 3.3% of subjects were colonised with HLSR, HLGR and AR Enterococcus spp. Carriage of HLGR, HLSR and AR isolates was associated with prior antibiotic consumption (P≤0.05). Additionally, male sex and antacid consumption were associated with AR enterococcal carriage. Moreover, 69 (97.2%), 10 (90.9%) and 9 (90.0%) of HLSR, HLGR and AR isolates were multidrug-resistant, respectively. No vancomycin-resistant enterococci were detected. ERIC-PCR revealed high genetic diversity among isolates. gelE and asa1 were major virulence genes both in E. faecalis and E. faecium. Presence of gelE was associated with HLSR and HLGR phenotypes (P≤0.05). Community intestinal carriage of HLSR enterococci was high; however, carriage of HLGR and AR enterococci was low.