Prevalence and genetic diversity of optrA-positive enterococci isolated from patients in an anorectal surgery ward of a Chinese hospital

Linezolid-resistant enterococci have increased in recent years due to the worldwide spread of acquired resistance genes (<i>cfr</i>, <i>optrA</i>, and <i>poxtA</i>) in clinical, animal, and environmental settings. This study investigated the carriage of <i>optrA</i>-positive enterococci among patients in the anorectal surgery ward in Hangzhou, China, and characterized the genetic context of <i>optrA</i>. A total of 173 wound secretion samples were obtained to screen <i>optrA</i>-positive enterococci. Of the 173 samples, 15 (8.67%) were positive for <i>optrA</i>, including 12 <i>Enterococcus faecalis</i>, two <i>E. faecium</i>, and one <i>E. hirae</i>. Multilocus sequence type analysis revealed that 12 <i>optrA</i>-positive <i>E. faecalis</i> isolates belonged to eight different sequence types (STs), of which ST16 was the main type. Eight optrA variants were identified, whose <i>optrA</i> flanking regions with a <i>fexA</i> gene downstream were bounded by different mobile genetic elements. Furthermore, the <i>optrA</i> gene in 8 out of 15 <i>optrA</i>-positive enterococci could be successfully transferred through conjugation. The findings revealed a high carriage rate of <i>optrA</i> in enterococci from one anorectal surgery ward in China. The dissemination of <i>optrA</i>-positive enterococci isolates in clinical settings should be continually monitored.