背景:金黄色葡萄球菌,一种共生细菌,定植于大约30%的人口的皮肤和粘膜。除了传统的抵抗机制,金黄色葡萄球菌的致病特征之一是其在生物和非生物表面上以生物膜状态存活的能力。由于这个特点,金黄色葡萄球菌是人类感染的主要原因,耐甲氧西林金黄色葡萄球菌(MRSA)是社区获得性和医院获得性感染的重要原因。
结果:对2014年至2020年中国7个省市的MRSA非重复临床分离株进行分析,发现53.2%的MRSA分离株表现出不同程度的生物膜产生能力。广东MRSA分离株的生物膜阳性率明显较高,江西,和湖北。本研究中收集的主要MRSA菌株是序列类型ST59,ST5和ST239,生物膜生产能力主要分布在这些ST类型中的中度和弱生物膜生产者中。值得注意的是,某些序列类型,例如ST88,表现出强生物膜产生菌株的高流行率。研究发现,SCCmecIV是生物膜阳性MRSA中的主要类型,其次是SCCmecII。比较具有弱和强生物膜生产能力的菌株,强生物膜生产者中sdrD和sdrE的阳性率较高。遗传决定因素ebp,icaA,icaB,icaC,icaD,icaR,和sdrE与MRSA中强大的生物膜产生有关。此外,生物膜阴性MRSA分离株对头孢霉素的敏感性较高(94.8%),达托霉素(94.5%),莫匹罗星(86.5%),替考拉宁(94.5%),夫西地酸(81.0%),与生物膜阳性MRSA分离株相比,达巴万星(94.5%)。在所有收集的样本类型中,生物膜阳性率始终高于50%。
结论:具有生物膜生产能力的MRSA菌株值得提高警惕。
BACKGROUND: Staphylococcus aureus, a commensal bacterium, colonizes the skin and mucous membranes of approximately 30% of the human population. Apart from conventional resistance mechanisms, one of the pathogenic features of S. aureus is its ability to survive in a biofilm state on both biotic and abiotic surfaces. Due to this characteristic, S. aureus is a major cause of human infections, with Methicillin-Resistant Staphylococcus aureus (MRSA) being a significant contributor to both community-acquired and hospital-acquired infections.
RESULTS: Analyzing non-repetitive clinical isolates of MRSA collected from seven provinces and cities in China between 2014 and 2020, it was observed that 53.2% of the MRSA isolates exhibited varying degrees of ability to produce biofilm. The biofilm positivity rate was notably high in MRSA isolates from Guangdong, Jiangxi, and Hubei. The predominant MRSA strains collected in this study were of sequence types ST59, ST5, and ST239, with the biofilm-producing capability mainly distributed among moderate and weak biofilm producers within these ST types. Notably, certain sequence types, such as ST88, exhibited a high prevalence of strong biofilm-producing strains. The study found that SCCmec IV was the predominant type among biofilm-positive MRSA, followed by SCCmec II. Comparing strains with weak and strong biofilm production capabilities, the positive rates of the sdrD and sdrE were higher in strong biofilm producers. The genetic determinants ebp, icaA, icaB, icaC, icaD, icaR, and sdrE were associated with strong biofilm production in MRSA. Additionally, biofilm-negative MRSA isolates showed higher sensitivity rates to cefalotin (94.8%), daptomycin (94.5%), mupirocin (86.5%), teicoplanin (94.5%), fusidic acid (81.0%), and dalbavancin (94.5%) compared to biofilm-positive MRSA isolates. The biofilm positivity rate was consistently above 50% in all collected specimen types.
CONCLUSIONS: MRSA strains with biofilm production capability warrant increased vigilance.