AUTHOR=Ma Xiaoyu , Zhang Fan , Bai Bing , Lin Zhiwei , Xu Guangjian , Chen Zhong , Sun Xiang , Zheng Jinxin , Deng Qiwen , Yu Zhijian 

TITLE=Linezolid Resistance in Enterococcus faecalis Associated With Urinary Tract Infections of Patients in a Tertiary Hospitals in China: Resistance Mechanisms, Virulence, and Risk Factors

JOURNAL=Frontiers in Public Health

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2021.570650

DOI=10.3389/fpubh.2021.570650

ISSN=2296-2565

ABSTRACT=<p><bold>Background:</bold><italic>Enterococcus faecalis</italic> has been commonly considered as one of the major pathogens of the urinary tract infection (UTI) in human host worldwide, whereas the molecular characteristics of <italic>E. faecalis</italic> clinical isolates from the patients with UTI in China remains seldomly reported. This study aimed to investigate the resistance mechanism, molecular characteristics and risk factors of <italic>E. faecalis</italic> clinical isolates from patients with UTI in China.</p><p><bold>Methods:</bold> A total of 115 non-duplicated <italic>E. faecalis</italic> clinical isolates from patients with UTI were retrospectively collected in a tertiary hospital in China and their clinical data was further analyzed. The linezolid and tedizolid susceptibility were determined by agar dilution. The resistance genes, including <italic>erm</italic>(A)<italic>, erm</italic>(B)<italic>, erm</italic>(C)<italic>, tet</italic>(M)<italic>, optrA, cfr, cfr</italic>(B), <italic>poxtA</italic>, and MLST-based housekeeping genes were investigated by PCR.</p><p><bold>Results:</bold> In 115 non-duplicated <italic>E. faecalis</italic> clinical isolates from the patients with UTI in this hospital setting, the frequency of linezolid or tedizolid-resistant/intermediate isolates were 22.61 and 13.04%, respectively, and the frequency of linezolid-resistant/intermediate <italic>E. faecalis</italic> clinical isolates carrying with <italic>erm</italic>(A) were 86%. Among the five linezolid-resistant <italic>E. faecalis</italic> strains found in this study, three <italic>optrA-</italic>positive isolates and the other two linezolid-resistant strains were G2576U genetic mutations in the V domain of the 23S rRNA genes. The ST clonality analysis indicated that 31.42% (11/35) of ST16 <italic>E. faecalis</italic> UTI isolates were not susceptible to linezolid. Moreover, the univariable analysis indicated that the high risk factors of linezolid-resistant/intermediate <italic>E. faecalis</italic> infections involved the indwelling catheter, trachea cannula catheter and the carriage of <italic>erm</italic>(A) or <italic>optrA</italic>. Furthermore, the indwelling catheter and trachea cannula catheter were demonstrated as the independent predictors of linezolid-resistant/intermediate <italic>E. faecalis</italic> strains in patients with UTI by multivariable analysis.</p><p><bold>Conclusion:</bold> Linezolid-resistant/intermediate <italic>E. faecalis</italic> associated with urinary tract infections of patients in this hospital setting from China might be explained by the high carriage frequency of <italic>optrA</italic> genes and moreover, indwelling catheter and trachea cannula should be considered as the independent predictors of linezolid-resistant/intermediate <italic>E. faecalis</italic> infections. The transmission mechanism of linezolid-resistant/intermediate <italic>E. faecalis</italic> in this hospital setting should be further studied.</p>