Table_2_Clonal Diversity and Epidemiological Characteristics of ST239-MRSA Strains.docx

Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen associated with severe morbidity and mortality and poses a significant threat to public health worldwide. The genetic diversity based on sequence types of MRSA strains was illustrated in previous studies; meanwhile, the diversity along with the predominant sequence type, especially in Egypt, remains unknown. The purpose of the current study was to determine the diversity of the predominant MRSA clone ST239-MRSA (n = 50) isolated from different hosts and clinical samples and to illustrate the correlation between the resistance patterns, toxin genes, and the genetic background in Port-said and El-Sharkia Governorates, Egypt. The ST239-MRSA clone was analyzed by phenotypic antibiotyping and various genotypic assays comprising SCCmec, agr, spa, coa, and coa-RFLP in addition to toxin gene profiles. Most of the analyzed strains (40/50, 80%) were multidrug resistant (MDR), belonged to SCCmec-III, agr-I, and coa genotype I, and harbored sea and pvl genes. A negative correlation between the toxin gene profiles and antimicrobial resistance was recorded. Meanwhile, the correlation between the toxin gene profiles and the genetic background was not observed in this study. Although ST239-MRSA strains belonged to a single sequence type, they exhibited a high degree of phenotypic and genotypic diversity, indicating weak clonality and adaptability. With such diversity, it is assumed that these strains may have undergone different evolutionary processes during transmission events among and/or within a single host or tissue niche.

耐甲氧西林金黄色葡萄球菌（MRSA）是一种与严重发病率和死亡率相关的重大病原体，对全球公共卫生构成了重大威胁。先前的研究基于MRSA菌株的序列类型揭示了其遗传多样性；然而，包括主要序列类型在内的多样性，尤其在埃及，尚属未知。本研究旨在确定从不同宿主和临床样本中分离出的主要MRSA克隆ST239-MRSA（n=50）的遗传多样性，并描绘其在埃及的Port-said和El-Sharkia省的耐药模式、毒素基因与遗传背景之间的相关性。ST239-MRSA克隆通过表型抗生素分型以及包括SCCmec、agr、spa、coa和coa-RFLP在内的多种基因型检测进行分析，此外还分析了毒素基因谱。大多数分析菌株（40/50，80%）为多重耐药性（MDR），属于SCCmec-III、agr-I和coa基因型I，并携带sea和pvl基因。记录到毒素基因谱与抗菌耐药性之间的负相关。同时，在本研究中并未观察到毒素基因谱与遗传背景之间的相关性。尽管ST239-MRSA菌株属于单一序列类型，但它们表现出高度的表型和基因型多样性，表明其克隆性较弱且具有适应性。鉴于这种多样性，假设这些菌株可能在宿主之间或单一宿主或组织生态位内的传播事件中经历了不同的进化过程。