Hospital intensive care units (ICUs) are known reservoirs of multidrug resistant nosocomial bacteria. Targeted environmental monitoring of these organisms in health care facilities can strengthen infection control procedures. A routine surveillance of extended spectrum beta-lactamase (ESBL) producers in a large Australian veterinary teaching hospital detected the opportunistic pathogen Enterobacter hormaechei in a hand washing sink of the ICU. The organism persisted for several weeks, despite two disinfection attempts. Four isolates were characterized in this study. Brilliance-ESBL selective plates were inoculated from environmental swabs collected throughout the hospital. Presumptive identification was done by conventional biochemistry. Genomes of multidrug resistant Enterobacter were entirely sequenced with Illumina and Nanopore platforms. Phylogenetic markers, mobile genetic elements and antimicrobial resistance genes were identified in silico. Antibiograms of isolates and transconjugants were established with Sensititre microdilution plates. The isolates possessed a chromosomal Tn7-associated silver/copper resistance locus and a large IncH12 conjugative plasmid encoding resistance against tellurium, arsenic, mercury and nine classes of antimicrobials. Clusters of antimicrobial resistance genes were associated with class 1 integrons and IS26, IS903 and ISCR transposable elements. The blaSHV-12, qnrB2 and mcr-9.1 genes, respectively conferring resistance to cephalosporins, quinolones and colistin, were present in a locus flanked by two IS903 copies. ESBL production and enrofloxacin resistance were confirmed phenotypically. The isolates appeared susceptible to colistin, possibly reflecting the inducible nature of mcr-9.1. The persistence of this strain in the veterinary hospital represented a risk of further accumulation and dissemination of antimicrobial resistance, prompting a thorough disinfection of the ICU. The organism was not recovered from subsequent environmental swabs, and nosocomial Enterobacter infections were not observed in the hospital during that period. This study shows that targeted routine environmental surveillance programs to track organisms with major resistance phenotypes, coupled with disinfection procedures and follow-up microbiological cultures are useful to control these risks in sensitive areas of large veterinary hospitals.

中文翻译：

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霍马氏肠杆菌菌株对兽医医院洗手槽的定殖

医院重症监护病房 (ICU) 是已知的耐多药医院内细菌的宿主。在卫生保健设施中对这些生物进行有针对性的环境监测可以加强感染控制程序。澳大利亚一家大型兽医教学医院对超广谱 β-内酰胺酶 (ESBL) 生产者的常规监测在 ICU 的洗手池中检测到机会性病原体霍马氏肠杆菌。尽管进行了两次消毒尝试，但该生物体仍持续了数周。在这项研究中对四种分离株进行了表征。Brilliance-ESBL 选择性平板是从整个医院收集的环境拭子中接种的。通过常规生物化学进行推定鉴定。多药耐药肠杆菌的基因组使用 Illumina 和 Nanopore 平台进行了完全测序。在计算机上鉴定了系统发育标记、移动遗传元件和抗菌素抗性基因。使用 Sensititre 微量稀释板建立分离物和转接合子的抗菌谱。分离株具有染色体 Tn7 相关的银/铜抗性基因座和编码对碲、砷、汞和九类抗微生物剂的抗性的大型 IncH12 共轭质粒。抗菌素耐药基因簇与 1 类整合子和 IS26、IS903 和 ISCR 转座元件相关。blaSHV-12、qnrB2 和 mcr-9.1 基因，分别赋予对头孢菌素、喹诺酮类和粘菌素的抗性，存在于两侧有两个 IS903 拷贝的基因座中。ESBL 产生和恩诺沙星耐药性在表型上得到证实。分离株似乎对粘菌素敏感，可能反映了 mcr-9.1 的诱导性质。这种菌株在兽医医院的持续存在代表了抗菌素耐药性进一步积累和传播的风险，促使对 ICU 进行彻底消毒。随后的环境拭子中没有回收到该生物体，并且在此期间医院未观察到院内肠杆菌感染。这项研究表明，跟踪具有主要耐药表型的生物体的有针对性的常规环境监测计划，加上消毒程序和后续微生物培养，有助于控制大型兽医医院敏感区域的这些风险。这种菌株在兽医医院的持续存在代表了抗菌素耐药性进一步积累和传播的风险，促使对 ICU 进行彻底消毒。随后的环境拭子中没有回收到该生物体，并且在此期间医院未观察到院内肠杆菌感染。这项研究表明，跟踪具有主要耐药表型的生物体的有针对性的常规环境监测计划，加上消毒程序和后续微生物培养，有助于控制大型兽医医院敏感区域的这些风险。这种菌株在兽医医院的持续存在代表了抗菌素耐药性进一步积累和传播的风险，促使对 ICU 进行彻底消毒。随后的环境拭子中没有回收到该生物体，并且在此期间医院未观察到院内肠杆菌感染。这项研究表明，跟踪具有主要耐药表型的生物体的有针对性的常规环境监测计划，加上消毒程序和后续微生物培养，有助于控制大型兽医医院敏感区域的这些风险。期间未在医院观察到院内肠杆菌感染。这项研究表明，跟踪具有主要耐药表型的生物体的有针对性的常规环境监测计划，加上消毒程序和后续微生物培养，有助于控制大型兽医医院敏感区域的这些风险。期间未在医院观察到院内肠杆菌感染。这项研究表明，跟踪具有主要耐药表型的生物体的有针对性的常规环境监测计划，加上消毒程序和后续微生物培养，有助于控制大型兽医医院敏感区域的这些风险。