Yoon Sunghyun, Lee Young Ju
Division of Microbiology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
College of Veterinary Medicine & Zoonoses Research Institute, Kyungpook National University, Daegu 41566, Korea.
Animals (Basel). 2021 Mar 2;11(3):661. doi: 10.3390/ani11030661.
Enterococci are considered to be environmental mastitis-causing pathogens that can easily spread antimicrobial resistance or virulence genes via horizontal transfer. In this study, the molecular characteristics of enterococci from bulk tank milk were investigated to assess the importance of dairy herd management. A total of 338 enterococci (305 and 33 ) were isolated from 1584 batches of bulk tank milk samples from 396 farms affiliated with four dairy companies in Korea, and significant differences (40.6-79.7%) ( < 0.05) in the prevalence of enterococci were observed in the samples from different companies. Enterococci showed the highest resistance to tetracycline (TET) (73.4%), followed by doxycycline (DOX) (49.7%) and erythromycin (ERY) (46.2%), while two enterococci isolates showed resistance to vancomycin (VAN). Among 146 tetracycline (TET) and ERY-resistant enterococci, each 50 (19.4%) enterococci carried combination-resistance and transposon gene types (B) + (M) + and (B) + (L) + (M) + , respectively. The virulence genes such as (99.0%), (97.7%), (95.7%), and (85.9%) were highly conserved in and significantly predominated over ( < 0.001). Our results indicate that pathogens from bulk tank milk can also become a reservoir for the dissemination of antimicrobial resistance and virulence factors through cross-contamination processes.
肠球菌被认为是引起环境性乳腺炎的病原体，可通过水平转移轻易传播抗微生物耐药性或毒力基因。在本研究中，对来自奶罐乳的肠球菌的分子特征进行了调查，以评估奶牛场管理的重要性。从韩国四家乳制品公司下属396个农场的1584批次奶罐乳样品中总共分离出338株肠球菌（305株和33株），在不同公司的样品中观察到肠球菌流行率存在显著差异（40.6 - 79.7%）（P < 0.05）。肠球菌对四环素（TET）的耐药性最高（73.4%），其次是强力霉素（DOX）（49.7%）和红霉素（ERY）（46.2%），而有两株肠球菌分离株对万古霉素（VAN）耐药。在146株对四环素（TET）和红霉素耐药的肠球菌中，分别有50株（19.4%）肠球菌携带联合耐药和转座子基因类型（B） + （M） + 和（B） + （L） + （M） + 。毒力基因如（99.0%）、（97.7%）、（95.7%）和（85.9%）在中高度保守，并显著多于（P < 0.001）。我们的结果表明，来自奶罐乳的病原体也可能通过交叉污染过程成为抗微生物耐药性和毒力因子传播的储存库。
