Garza-González Elvira, Morfin-Otero Rayo, Martínez-Vázquez Manuel A, Gonzalez-Diaz Esteban, González-Santiago Omar, Rodríguez-Noriega Eduardo
Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico.
Scand J Infect Dis. 2011 Dec;43(11-12):930-6. doi: 10.3109/00365548.2011.598873. Epub 2011 Aug 19.
The incidence of coagulase-negative staphylococci reported as causative agents of nosocomial infections has risen in the last decade. The aim of this study was to characterize biofilm formation, antibiotic resistance, SCCmec type, and genetic relatedness in clinical isolates of Staphylococcus cohnii, Staphylococcus hominis, and Staphylococcus sciuri recovered from humans.
Clinically relevant isolates of S. cohnii (n = 15), S. hominis (n = 9), and S. sciuri (n = 6), were collected from patients. Biofilm formation was evaluated using crystal violet staining, drug susceptibility was assessed using the broth microdilution method, and methicillin resistance was measured using the cefoxitin disk test. SCCmec was typed using 2 different methodologies, and genetic relatedness was determined by pulsed-field gel electrophoresis (PFGE).
Sixty percent (9/15) of S. cohnii, 33% (3/9) of S. hominis, and 50% (3/6) of S. sciuri isolates were categorized as weak producers of biofilm. None of the isolates were resistant to vancomycin or linezolid. All 3 species showed a high resistance (> 66%) to ampicillin, levofloxacin, erythromycin, and ceftriaxone, and the majority of the isolates were methicillin-resistant. PFGE revealed that the S. cohnii isolates comprised 1 dominant clone.
The S. cohnii, S. hominis, and S. sciuri isolates analyzed in this study showed a high methicillin resistance and resistance to other antimicrobials. The results of this study strongly suggest that coagulase-negative staphylococci harbour new SCCmec elements. We report the first case of a clone of S. cohnii associated with human disease.
在过去十年中，作为医院感染病原体报道的凝固酶阴性葡萄球菌的发病率有所上升。本研究的目的是对从人类分离出的科氏葡萄球菌、人葡萄球菌和松鼠葡萄球菌临床分离株的生物膜形成、抗生素耐药性、葡萄球菌染色体盒式 mec（SCCmec）类型及遗传相关性进行特征分析。
从患者中收集了具有临床相关性的科氏葡萄球菌（n = 15）、人葡萄球菌（n = 9）和松鼠葡萄球菌（n = 6）分离株。使用结晶紫染色评估生物膜形成，采用肉汤微量稀释法评估药物敏感性，并使用头孢西丁纸片扩散法测定耐甲氧西林情况。采用两种不同方法对 SCCmec 进行分型，并通过脉冲场凝胶电泳（PFGE）确定遗传相关性。
60%（9/15）的科氏葡萄球菌分离株、33%（3/9）的人葡萄球菌分离株和 50%（3/6）的松鼠葡萄球菌分离株被归类为生物膜弱产生菌。所有分离株对万古霉素或利奈唑胺均无耐药性。所有这三种菌对氨苄西林、左氧氟沙星、红霉素和头孢曲松均表现出高耐药性（> 66%），且大多数分离株耐甲氧西林。PFGE 显示科氏葡萄球菌分离株包含 1 个优势克隆。
本研究分析的科氏葡萄球菌、人葡萄球菌和松鼠葡萄球菌分离株表现出高耐甲氧西林性及对其他抗菌药物的耐药性。本研究结果强烈表明凝固酶阴性葡萄球菌含有新的 SCCmec 元件。我们报道了首例与人类疾病相关的科氏葡萄球菌克隆。
