Laboratory of Food Microbiology and Hygiene, Faculty of Veterinary Medicine, Menofia University, Sadat City, Egypt.
Int J Food Microbiol. 2012 Jun 1;156(3):286-9. doi: 10.1016/j.ijfoodmicro.2012.03.022. Epub 2012 Mar 28.
Staphylococci are not part of the normal fish microflora. The presence of staphylococci on fish is an indication of (a) post-harvest contamination due to poor personnel hygiene, or (b) disease in fish. The aim of this study was to determine the prevalence, molecular genetic characteristics, antibiotic resistance and virulence factors of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from 200 samples of retail ready-to-eat raw fish (sashimi) collected from the Japanese prefecture of Hiroshima. We characterized 180 staphylococcal strains. A majority of the grocery stores surveyed (92%, 23/25) contained fish contaminated with Staphylococcus species. We recovered 175 S. aureus isolates from 174 (87%, 174/200) samples, with 170 isolates of MSSA. For the MRSA and MR-CoNS, 10 isolates were obtained from 10 samples (5%, 10/200) collected from 10 shops (40%, 10/25) belonging to four supermarket chains. SCCmec typing revealed the presence of a type IV.1 SCCmec cassette in S. warneri isolates, a type II.1 SCCmec cassette in S. haemolyticus isolates and a cassette in methicillin-resistant S. aureus (MRSA) isolates that could not be typed. Molecular typing of two MRSA isolates by spa sequencing and multilocus sequence typing (MLST) identified t1767 and ST8, respectively. Antibiotic resistance genes that confer resistance to aminoglycosides, tetracyclines, β-lactams, macrolides, lincosamides and streptogramin B (MLS(B)) antibiotics were detected. Genes encoding one or more of the following virulence factors: staphylococcal enterotoxins (seb, and sed), toxic shock syndrome toxin 1 (tst), exfoliative toxin (etaA) were detected in 14.2% (25/175) of S. aureus isolates. The accessory gene regulator (agr) typing of S. aureus isolates revealed that agr type 1 was most prevalent (96.5%, 169/175) followed by type 2 (2.2%, 4/175) and type 3 (1.1%, 2/175). None of the S. aureus isolates carried the Panton-Valentine leucocidin (PVL) encoding genes, lukF-PV and lukS-PV. To the best of our knowledge, this is the first report to show MRSA and MR-CoNS isolated from retail ready-to-eat food in Japan. Our results showed that sashimi is a likely vehicle for transmission of multidrug-resistant and toxigenic staphylococci.
葡萄球菌不是鱼类正常微生物群的一部分。葡萄球菌在鱼类上的存在表明(a)由于人员卫生条件差导致的收获后污染，或(b)鱼类患病。本研究旨在确定从日本广岛县的 200 份零售即食生鱼片（刺身）样本中分离的甲氧西林敏感金黄色葡萄球菌（MSSA）、耐甲氧西林金黄色葡萄球菌（MRSA）和耐甲氧西林凝固酶阴性葡萄球菌（MR-CoNS）的流行率、分子遗传特征、抗生素耐药性和毒力因子。我们对 180 株葡萄球菌进行了表征。在所调查的杂货店中，有 92%（25/25）的杂货店的鱼类受到了葡萄球菌的污染。我们从 200 份样本中的 174 份（87%，174/200）中回收了 175 株金黄色葡萄球菌分离株，其中 170 株为 MSSA。对于 MRSA 和 MR-CoNS，从属于四个连锁超市的 10 家商店（40%，10/25）的 10 份样本（5%，10/200）中获得了 10 株。SCCmec 型分析显示，S. warneri 分离株存在 IV.1 型 SCCmec 盒，S. haemolyticus 分离株存在 II.1 型 SCCmec 盒，而无法对耐甲氧西林金黄色葡萄球菌（MRSA）分离株进行分型。通过 spa 测序和多位点序列分型（MLST）对 2 株 MRSA 分离株的分子分型表明，分别为 t1767 和 ST8。检测到了赋予氨基糖苷类、四环素类、β-内酰胺类、大环内酯类、林可酰胺类和糖肽类 B（MLS(B)）抗生素耐药性的抗生素耐药基因。在 14.2%（25/175）的金黄色葡萄球菌分离株中检测到了编码以下一种或多种毒力因子的基因：葡萄球菌肠毒素（seb 和 sed）、中毒性休克综合征毒素 1（tst）、表皮剥脱毒素（etaA）。金黄色葡萄球菌分离株的辅助基因调节（agr）分型显示，agr 型 1 最为常见（96.5%，169/175），其次是 2 型（2.2%，4/175）和 3 型（1.1%，2/175）。金黄色葡萄球菌分离株均未携带编码 Panton-Valentine 白细胞毒素（PVL）的 lukF-PV 和 lukS-PV 基因。据我们所知，这是首次报道从日本零售即食食品中分离出耐甲氧西林金黄色葡萄球菌和耐甲氧西林凝固酶阴性葡萄球菌。我们的结果表明，刺身可能是传播多药耐药和产毒葡萄球菌的媒介。
