Cheddie Paul, Dziva Francis, Akpaka Patrick Eberechi
Department of Medical Technology, University of Guyana, Georgetown, Guyana.
Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago.
Ann Clin Microbiol Antimicrob. 2017 May 8;16(1):33. doi: 10.1186/s12941-017-0209-x.
Identification of the prevalence and spread of ESBL-mediated antibiotic resistance is essential especially in the hospital setting. It is for this reason, more and more studies are highlighting the importance of complementing phenotypic ESBL-detection techniques with molecular techniques in order to understand the basis and extent of this form of resistance among clinically evolved bacterial populations, especially those belonging to the Enterobacteriaceae family. However, in Trinidad and Tobago and other Caribbean countries, very little is known regarding ESBL detection rates and/or the prevalence of genes conferring ESBL resistance.
Sixty-six Klebsiella pneumoniae isolates from clinical specimens phenotypically identified by the Microscan Walkaway-96 System as potential ESBL-producers were analysed in this study. Screening and confirmation of these isolates as ESBL producers was done by the Clinical and Laboratory Standards Institute (CLSI) approved methods. Polymerase chain reaction amplification of beta-lactamase genes bla , bla , bla , bla and bla was performed to identify mechanisms of β-lactam resistance.
ESBL-producing K. pneumoniae was confirmed in 78.8% (41/52) from isolates collected from a variety of sources during the period, April-July 2015. bla (84.8%) and bla (46.9%) were the predominant β-lactamase genes identified. A single K. pneumoniae isolate possessed a bla group 2 beta-lactamase gene. RAPD analysis identified a number of epidemiologically related isolates. However, current isolates were unrelated to isolates from previous years.
This study revealed that among K. pneumoniae isolates exhibiting extended spectrum β-lactam resistance, there was a high prevalence of bla and bla genes. This result highlights the need for a reliable epidemiological apparatus that involves the molecular characterisation of ESBL resistance.
确定超广谱β-内酰胺酶（ESBL）介导的抗生素耐药性的流行情况和传播途径至关重要，尤其是在医院环境中。正因如此，越来越多的研究强调了用分子技术补充ESBL表型检测技术的重要性，以便了解这种耐药形式在临床进化的细菌群体，特别是肠杆菌科细菌群体中的耐药基础和程度。然而，在特立尼达和多巴哥以及其他加勒比国家，关于ESBL检测率和/或赋予ESBL耐药性的基因的流行情况知之甚少。
本研究分析了66株肺炎克雷伯菌分离株，这些分离株通过Microscan Walkaway-96系统从临床标本中表型鉴定为潜在的ESBL产生菌。采用临床和实验室标准协会（CLSI）批准的方法对这些分离株进行ESBL产生菌的筛选和确认。进行β-内酰胺酶基因bla、bla、bla、bla和bla的聚合酶链反应扩增，以确定β-内酰胺耐药机制。
在2015年4月至7月期间从各种来源收集的分离株中，78.8%（41/52）的肺炎克雷伯菌被确认为产ESBL菌。bla（84.8%）和bla（46.9%）是鉴定出的主要β-内酰胺酶基因。一株肺炎克雷伯菌分离株拥有bla组2β-内酰胺酶基因。随机扩增多态性DNA（RAPD）分析确定了一些流行病学相关的分离株。然而，当前的分离株与前几年的分离株无关。
本研究表明，在表现出超广谱β-内酰胺耐药性的肺炎克雷伯菌分离株中，bla和bla基因的流行率很高。这一结果凸显了需要一个可靠的流行病学检测工具，该工具涉及ESBL耐药性的分子特征分析。
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