We have screened 2568 healthy individuals (mostly children) for Staphylococcus aureus and Streptococcus pneumoniae nasal carriage between 2010 and 2012. Out of the isolated 751 S. aureus strains, we found one methicillin-sensitive catalase-negative S. aureus (CNSA). Our CNSA isolate possessed a novel nonsense point mutation in the katA gene leading to early truncation of the protein product. The strain was resistant to penicillin and erythromycin, but sensitive to all other tested antibiotics and carried the enterotoxin A gene. It belonged to sequence type 5 (ST5), which is a successful, worldwide spread, usually MRSA clone. Catalase has been described as a virulence factor strictly required for nasal colonisation, and this is the first case contradicting this theory, as all previous CNSA isolates derived from infections. This is the first report of a CNSA from a symptomless carrier as well as the first occurrence in Hungary.

中文翻译：

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首先描述来自健康载体的过氧化氢酶阴性金黄色葡萄球菌，在katA基因中有新的无意义突变。

我们在2010年至2012年之间对2568名健康个体（主要是儿童）进行了金黄色葡萄球菌和肺炎链球菌鼻支架的筛查。在分离出的751株金黄色葡萄球菌中，我们发现了一种对甲氧西林敏感的过氧化氢酶阴性的金黄色葡萄球菌（CNSA）。我们的CNSA分离物在katA基因中具有新的无意义点突变，可导致蛋白质产物的早期截断。该菌株对青霉素和红霉素有抗性，但对所有其他测试的抗生素敏感，并带有肠毒素A基因。它属于序列类型5（ST5），是一种成功的，在世界范围内传播的，通常为MRSA克隆。过氧化氢酶已被描述为鼻内定植严格要求的毒力因子，这是与该理论相矛盾的第一种情况，因为以前所有的CNSA分离株均源自感染。