Paniagua-Contreras Gloria Luz, Monroy-Pérez Eric, Vaca-Paniagua Felipe, Rodríguez-Moctezuma José Raymundo, Negrete-Abascal Erasmo, Vaca Sergio
FES-Iztacala, Universidad Nacional Autónoma de México, Av, de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla, 54090, Edo, de México, México.
Ann Clin Microbiol Antimicrob. 2014 Jan 9;13:6. doi: 10.1186/1476-0711-13-6.
Methicillin-resistant Staphylococcus aureus (MRSA) are clinically relevant pathogens that cause severe catheter-related nosocomial infections driven by several virulence factors.
We implemented a novel model of infection in vitro of reconstituted human epithelium (RHE) to analyze the expression patterns of virulence genes in 21 MRSA strains isolated from catheter-related infections in Mexican patients undergoing haemodialysis. We also determined the phenotypic and genotypic co-occurrence of antibiotic- and disinfectant-resistance traits in the S. aureus strains, which were also analysed by pulsed-field-gel electrophoresis (PFGE).
In this study, MRSA strains isolated from haemodialysis catheter-related infections expressed virulence markers that mediate adhesion to, and invasion of, RHE. The most frequent pattern of expression (present in 47.6% of the strains) was as follows: fnbA, fnbB, spa, clfA, clfB, cna, bbp, ebps, eap, sdrC, sdrD, sdrE, efb, icaA, and agr. Seventy-one percent of the strains harboured the antibiotic- and disinfectant-resistance genes ermA, ermB, tet(M), tet(K), blaZ, qacA, qacB, and qacC. PFGE of the isolated MRSA revealed three identical strains and two pairs of identical strains. The strains with identical PFGE patterns showed the same phenotypes and genotypes, including the same spa type (t895), suggesting hospital personnel manipulating the haemodialysis equipment could be the source of catheter contamination.
These findings help define the prevalence of MRSA virulence factors in catheter-related infections. Some of the products of the expressed genes that we detected in this work may serve as potential antigens for inclusion in a vaccine for the prevention of MRSA-catheter-related infections.
耐甲氧西林金黄色葡萄球菌（MRSA）是具有临床相关性的病原体，由多种毒力因子导致严重的导管相关医院感染。
我们实施了一种体外重组人上皮细胞（RHE）感染的新模型，以分析从墨西哥接受血液透析患者的导管相关感染中分离出的21株MRSA菌株中毒力基因的表达模式。我们还确定了金黄色葡萄球菌菌株中抗生素和消毒剂耐药性状的表型和基因型共现情况，并通过脉冲场凝胶电泳（PFGE）进行分析。
在本研究中，从血液透析导管相关感染中分离出的MRSA菌株表达介导与RHE粘附和侵袭的毒力标志物。最常见的表达模式（存在于47.6%的菌株中）如下：fnbA、fnbB、spa、clfA、clfB、cna、bbp、ebps、eap、sdrC、sdrD、sdrE、efb、icaA和agr。71%的菌株携带抗生素和消毒剂耐药基因ermA、ermB、tet(M)、tet(K)、blaZ、qacA、qacB和qacC。分离出的MRSA的PFGE显示出三株相同菌株和两对相同菌株。具有相同PFGE模式的菌株表现出相同的表型和基因型，包括相同的spa类型（t895），这表明操作血液透析设备的医院工作人员可能是导管污染的来源。
这些发现有助于确定MRSA毒力因子在导管相关感染中的流行情况。我们在这项工作中检测到的一些表达基因的产物可能作为潜在抗原，用于预防MRSA导管相关感染的疫苗中。
