巴西新生儿临床样本中分离的金黄色葡萄球菌和凝固酶阴性葡萄球菌中肠毒素 E、G、H 和 I 的分子检测。
Molecular detection of enterotoxins E, G, H and I in Staphylococcus aureus and coagulase-negative staphylococci isolated from clinical samples of newborns in Brazil.
机构信息
Department of Microbiology and Immunology, Institute of Biosciences, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brazil.
出版信息
J Appl Microbiol. 2011 Sep;111(3):749-62. doi: 10.1111/j.1365-2672.2011.05076.x. Epub 2011 Jul 6.
AIMS
The objective of this study was to investigate the detection of SEE, SEG, SEH and SEI in strains of Staphylococcus aureus and coagulase-negative staphylococci (CNS) using RT-PCR.
METHODS AND RESULTS
In this study, 90 Staph. aureus strains and 90 CNS strains were analysed by PCR for the detection of genes encoding staphylococcal enterotoxins (SE) E, G, H and I. One or more genes were detected in 54 (60%) Staph. aureus isolates and in 29 (32.2%) CNS isolates. Staphylococcus epidermidis was the most frequently isolated CNS species (n = 64, 71.1%), followed by Staphylococcus warneri (n = 8, 8.9%) and other species (Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus lugdunensis, Staphylococcus simulans, Staphylococcus saprophyticus and Staphylococcus xylosus: n = 18, 20%). The genes studied were detected in Staph. epidermidis, Staph. warneri, Staph. haemolyticus, Staph. hominis, Staph. simulans and Staph. lugdunensis. The highest frequency of genes was observed in Staph. epidermidis and Staph. warneri, a finding indicating differences in the pathogenic potential between CNS species and highlighting the importance of the correct identification of these micro-organisms. RT-PCR used for the detection of mRNA revealed the expression of SEG, SEH and/or SEI in 32 (59.3%) of the 90 Staph. aureus isolates, whereas expression of some of these genes was observed in 10 (34.5%) of the 90 CNS isolates.
CONCLUSIONS
Staphylococcus epidermidis was the most toxigenic CNS species. Among the other species, only Staph. warneri and Staph. lugdunensis presented a positive RT-PCR result. PCR was efficient in confirming the toxigenic capacity of Staph. aureus and CNS.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study permitted to confirm the toxigenic capacity of CNS to better characterize the pathogenic potential of this group of micro-organisms. In addition, it permitted the detection of SEG, SEH and SEI, enterotoxins that cannot be detected by commercially available immunological methods.
目的
本研究旨在使用 RT-PCR 检测金黄色葡萄球菌和凝固酶阴性葡萄球菌（CNS）菌株中 SEE、SEG、SEH 和 SEI 的检测。
方法和结果
在这项研究中，通过 PCR 分析了 90 株金黄色葡萄球菌和 90 株 CNS 菌株，以检测编码葡萄球菌肠毒素（SE）E、G、H 和 I 的基因。在 54 株（60%）金黄色葡萄球菌分离株和 29 株（32.2%）CNS 分离株中检测到一个或多个基因。表皮葡萄球菌是最常分离的 CNS 种（n = 64，71.1%），其次是沃氏葡萄球菌（n = 8，8.9%）和其他种（溶血葡萄球菌、人葡萄球菌、解乳糖葡萄球菌、模仿葡萄球菌、腐生葡萄球菌和木糖葡萄球菌：n = 18，20%）。研究中检测到的基因存在于表皮葡萄球菌、沃氏葡萄球菌、溶血葡萄球菌、人葡萄球菌、模仿葡萄球菌和解乳糖葡萄球菌中。在表皮葡萄球菌和沃氏葡萄球菌中观察到基因的最高频率，这一发现表明 CNS 种之间的致病潜力存在差异，并强调了正确识别这些微生物的重要性。用于检测 mRNA 的 RT-PCR 显示，在 90 株金黄色葡萄球菌分离株中，有 32 株（59.3%）检测到 SEG、SEH 和/或 SEI 的表达，而在 90 株 CNS 分离株中，有 10 株（34.5%）检测到这些基因的表达。
结论
表皮葡萄球菌是最具毒性的 CNS 种。在其他种中，只有沃氏葡萄球菌和路邓葡萄球菌的 RT-PCR 结果为阳性。PCR 可有效确认金黄色葡萄球菌和 CNS 的毒力。
意义和影响
本研究证实了 CNS 的毒力能力，从而更好地描述了该组微生物的致病潜力。此外，它还检测到了无法通过市售免疫方法检测到的 SEG、SEH 和 SEI 肠毒素。
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