Syed Muhammad Ali, Shah Syeda Hala Hussain, Sherafzal Yasmin, Shafi-Ur-Rehman Syed, Khan Mushtaq Ahmed, Barrett John B, Woodley Tiffanie A, Jamil Bushra, Abbasi Shahid Ahmad, Jackson Charlene R
1 Department of Microbiology, University of Haripur , Haripur, Pakistan .
2 Bacterial Epidemiology and Antimicrobial Resistance Research Unit, U.S. National Poultry Research Center, USDA-ARS , Athens, Georgia .
Foodborne Pathog Dis. 2018 Feb;15(2):86-93. doi: 10.1089/fpd.2017.2336. Epub 2017 Oct 25.
Table eggs are nutritionally important food consumed globally. Despite being protected inside the hard shell and a semipermeable membrane, the egg contents may be contaminated with microbes and thus become a possible carrier of infectious agents to humans. A number of medically significant bacterial species such as Salmonella enterica, Listeria monocytogenes, and Yersinia enterocolitica have already been reported from table eggs. More important is the presence of antimicrobial-resistant bacterial strains in this food source. The present study was aimed at detection and characterization of Staphylococcus aureus from table eggs collected from different retail shops in Haripur city of Pakistan. Staphylococci were isolated from 300 eggs collected from December 2015 to May 2016. S. aureus isolates were tested for antimicrobial susceptibility using broth microdilution and characterized using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, and spa typing. The presence of Panton-Valentine leukocidin and antimicrobial resistance genes were detected using PCR. Staphylococci were isolated from 21.3% (64/300) of the table eggs tested. Of those, 59% (38/64) were identified as S. aureus, of which 33 (86.8%) were positive for mecA (MRSA, methicillin-resistant S. aureus). All MRSA were multidrug resistant (resistant to two or more antimicrobial classes), contained aac-aph (encoding aminoglycosides), and were pvl. Using MLST, spa typing, and SCCmec typing, three genotypic patterns were assigned: ST8-t8645-MRSA-IV, associated with USA300; and ST772-t657-MRSA-IV and ST772-t8645-MRSA-IV, both characteristic of the Bengal Bay community-associated MRSA clone. Molecular typing by PFGE revealed that the bacterial population was highly homogenous with only two patterns observed. This study is the first report of detection of human-associated pvl MRSA from table eggs. The genetic similarities of MRSA present in the eggs to that of humans may suggest human to poultry transmission of MRSA via contamination.
食用蛋是全球范围内具有重要营养意义的食物。尽管蛋被坚硬的蛋壳和半透膜保护着，但其内容物仍可能被微生物污染，从而成为人类感染源的潜在载体。已有报道称，食用蛋中存在多种具有医学重要性的细菌物种，如肠炎沙门氏菌、单核细胞增生李斯特菌和小肠结肠炎耶尔森菌。更重要的是，这种食物来源中存在抗微生物的细菌菌株。本研究旨在检测和鉴定从巴基斯坦哈里普尔市不同零售店收集的食用蛋中的金黄色葡萄球菌。从2015年12月至2016年5月收集的300枚蛋中分离出葡萄球菌。使用肉汤微量稀释法对金黄色葡萄球菌分离株进行抗微生物敏感性测试，并使用脉冲场凝胶电泳（PFGE）、多位点序列分型（MLST）、葡萄球菌盒式染色体mec（SCCmec）分型和spa分型进行鉴定。使用聚合酶链反应（PCR）检测杀白细胞素和抗微生物耐药基因的存在。在所检测的300枚食用蛋中，21.3%（64/300）分离出葡萄球菌。其中，59%（38/64）被鉴定为金黄色葡萄球菌，其中33株（86.8%）mecA呈阳性（耐甲氧西林金黄色葡萄球菌，MRSA）。所有MRSA均对多种药物耐药（对两种或更多抗微生物类别耐药），含有aac-aph（编码氨基糖苷类），且携带杀白细胞素。使用MLST、spa分型和SCCmec分型，确定了三种基因型模式：与USA300相关的ST8-t8645-MRSA-IV；以及孟加拉湾社区相关MRSA克隆的特征性模式ST772-t657-MRSA-IV和ST772-t8645-MRSA-IV。PFGE分子分型显示，细菌群体高度同源，仅观察到两种模式。本研究是关于从食用蛋中检测出与人类相关的携带杀白细胞素MRSA的首次报道。蛋中存在的MRSA与人类的MRSA在基因上的相似性可能表明MRSA通过污染从人类传播到家禽。
