RESUMO
This study investigated resistance mechanisms and epidemiology of emerging linezolid-nonsusceptible Enterococcus faecalis (LNSEF) in a tertiary care hospital. LNSEF isolated from clinical samples were collected from November 2017 to June 2019. The isolates were investigated for linezolid resistance and the associated molecular mechanisms, including mutations of 23S rRNA domain V and acquisition of the cfr or optrA resistance gene. We used pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing for the molecular typing of the isolates. Among 4,318 E. faecalis isolates, 10 (0.23%) were linezolid-nonsusceptible. All LNSEF isolates were optrA-positive and cfr-negative. Of these isolates, five were sequence type (ST) 476, two ST585, one ST16, one ST16-like, and one ST480. Six LNSEF isolates obtained in the first year clustered to three types in the PFGE analysis: two ST476 isolates of type A, two ST585 isolates of type B, and two ST16 or ST16-like isolates of type C. Seven cases were of community-onset and three were hospital acquired, but total of eight were healthcare-associated including five community-onset. None of the patients had a history of linezolid treatment, and in one patient, we detected linezolid-susceptible E. faecalis one month before LNSEF detection. In conclusion, heterogenous clones of optrA-positive LNSEF emerged in the hospital mainly via community-onset.
RESUMO
optrA, a transferrable linezolid resistance gene, was identified in a clinical strain of En-terococcus faecalis isolated in China in 2015. This gene is 1968 bp in length, encoding 655 amino acids. And the sequence of these amino acids shares high homology with the amino acid sequence of ABC transport-er, resulting in resistance to oxazolidinones ( linezolid and tedizolid) and phenicols ( florfenicol and chloram-phenicol) . Linezolid is an important oxazolidinone antibiotic used in the treatment of refractory infections such as infections caused by methicillin-resistant Staphylococcus aureus. Therefore, the appearance and prev-alence of optrA gene have drawn worldwide attention. In this review, we focus on the discovery, epidemiolo-gy and molecular transmission mechanism of optrA gene.
RESUMO
optrA, a transferrable linezolid resistance gene, was identified in a clinical strain of En-terococcus faecalis isolated in China in 2015. This gene is 1968 bp in length, encoding 655 amino acids. And the sequence of these amino acids shares high homology with the amino acid sequence of ABC transport-er, resulting in resistance to oxazolidinones ( linezolid and tedizolid) and phenicols ( florfenicol and chloram-phenicol) . Linezolid is an important oxazolidinone antibiotic used in the treatment of refractory infections such as infections caused by methicillin-resistant Staphylococcus aureus. Therefore, the appearance and prev-alence of optrA gene have drawn worldwide attention. In this review, we focus on the discovery, epidemiolo-gy and molecular transmission mechanism of optrA gene.