血源人葡萄球菌生物被膜细胞的抗生素敏感性及分子特征分析
Antibiotic Susceptibility of Biofilm Cells and Molecular Characterisation of Staphylococcus hominis Isolates from Blood.
作者信息
Mendoza-Olazarán Soraya, Morfín-Otero Rayo, Villarreal-Treviño Licet, Rodríguez-Noriega Eduardo, Llaca-Díaz Jorge, Camacho-Ortiz Adrián, González Gloria M, Casillas-Vega Néstor, Garza-González Elvira
机构信息
Servicio de Gastroenterología, Hospital Universitario Dr. José Eleuterio González, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México.
Hospital Civil de Guadalajara, Fray Antonio Alcalde, and Instituto de Patología Infecciosa y Experimental, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, México.
出版信息
PLoS One. 2015 Dec 14;10(12):e0144684. doi: 10.1371/journal.pone.0144684. eCollection 2015.
OBJECTIVES
We aimed to characterise the staphylococcal cassette chromosome mec (SCCmec) type, genetic relatedness, biofilm formation and composition, icaADBC genes detection, icaD expression, and antibiotic susceptibility of planktonic and biofilm cells of Staphylococcus hominis isolates from blood.
METHODS
The study included 67 S. hominis blood isolates. Methicillin resistance was evaluated with the cefoxitin disk test. mecA gene and SCCmec were detected by multiplex PCR. Genetic relatedness was determined by pulsed-field gel electrophoresis. Biofilm formation and composition were evaluated by staining with crystal violet and by detachment assay, respectively; and the biofilm index (BI) was determined. Detection and expression of icaADBC genes were performed by multiplex PCR and real-time PCR, respectively. Antibiotic susceptibilities of planktonic cells (minimum inhibitory concentration, MIC) and biofilm cells (minimum biofilm eradication concentration, MBEC) were determined by the broth dilution method.
RESULTS
Eighty-five percent (57/67) of isolates were methicillin resistant and mecA positive. Of the mecA-positive isolates, 66.7% (38/57) carried a new putative SCCmec type. Four clones were detected, with two to five isolates each. Among all isolates, 91% (61/67) were categorised as strong biofilm producers. Biofilm biomass composition was heterogeneous (polysaccharides, proteins and DNA). All isolates presented the icaD gene, and 6.66% (1/15) isolates expressed icaD. This isolate presented the five genes of ica operon. Higher BI and MBEC values than the MIC values were observed for amikacin, vancomycin, linezolid, oxacillin, ciprofloxacin, and chloramphenicol.
CONCLUSIONS
S. hominis isolates were highly resistant to methicillin and other antimicrobials. Most of the detected SCCmec types were different than those described for S. aureus. Isolates indicated low clonality. The results indicate that S. hominis is a strong biofilm producer with an extracellular matrix with similar composition of proteins, DNA and N-acetylglucosamine; and presents high frequency and low expression of icaD gene. Biofilm production is associated with increased antibiotic resistance.
目的
我们旨在对人葡萄球菌血液分离株的葡萄球菌盒式染色体mec（SCCmec）类型、遗传相关性、生物膜形成及组成、icaADBC基因检测、icaD表达以及浮游菌和生物膜菌的抗生素敏感性进行特征分析。
方法
该研究纳入了67株人葡萄球菌血液分离株。采用头孢西丁纸片扩散法评估耐甲氧西林情况。通过多重PCR检测mecA基因和SCCmec。采用脉冲场凝胶电泳确定遗传相关性。分别通过结晶紫染色和脱离试验评估生物膜形成及组成；并确定生物膜指数（BI）。分别通过多重PCR和实时PCR进行icaADBC基因的检测和表达分析。采用肉汤稀释法测定浮游菌（最低抑菌浓度，MIC）和生物膜菌（最低生物膜清除浓度，MBEC）的抗生素敏感性。
结果
85%（57/67）的分离株耐甲氧西林且mecA阳性。在mecA阳性分离株中，66.7%（38/57）携带一种新的假定SCCmec类型。检测到4个克隆，每个克隆有2至5株分离株。在所有分离株中，91%（61/67）被归类为强生物膜产生菌。生物膜生物量组成具有异质性（多糖、蛋白质和DNA）。所有分离株均存在icaD基因，6.66%（1/15）的分离株表达icaD。该分离株呈现ica操纵子的5个基因。对于阿米卡星、万古霉素、利奈唑胺、苯唑西林、环丙沙星和氯霉素，观察到BI和MBEC值高于MIC值。
结论
人葡萄球菌分离株对甲氧西林和其他抗菌药物高度耐药。检测到的大多数SCCmec类型与金黄色葡萄球菌所描述的不同类型。分离株显示出低克隆性。结果表明，人葡萄球菌是一种强生物膜产生菌，其细胞外基质具有与蛋白质、DNA和N - 乙酰葡糖胺相似的组成；并且icaD基因呈现高频率和低表达。生物膜形成与抗生素耐药性增加相关。
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