van Duijkeren E, Ikawaty R, Broekhuizen-Stins M J, Jansen M D, Spalburg E C, de Neeling A J, Allaart J G, van Nes A, Wagenaar J A, Fluit A C
Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, PO Box 80165, Utrecht University, 3508 TD Utrecht, The Netherlands.
Vet Microbiol. 2008 Jan 25;126(4):383-9. doi: 10.1016/j.vetmic.2007.07.021. Epub 2007 Jul 25.
The main objective of the present study was to investigate if different kinds of pig farms, like farrowing farms and rearing farms, play a role in the transmission of methicillin-resistant Staphylococcus aureus (MRSA) to Dutch finishing farms. Twelve farrowing farms, 11 finishing farms, 6 farrow-to finish farms, 1 rearing farm and 1 centre for artificial insemination were included. Screening of 310 pigs from these 31 farms showed 35 pigs (11%) to carry MRSA in their nares. On 7 of the 31 (23%) investigated farms colonized pigs were found, including 3 finishing farms, 3 farrowing farms and 1 farrow-to-finish farm. The use of standard antimicrobial medication of the pigs seemed to be a risk factor for MRSA carriage. Screening of the pigs on six farms supplying pigs for the MRSA positive farms revealed that the pigs on all but one farm were MRSA positive. Genotyping revealed that all MRSA strains were non-typeable by PFGE using the SmaI restriction enzyme and had multilocus sequence type (MLST) ST398. Different spa-types were found including t011, t108, t567, t899 and t1939, but the spa-types on epidemiologically related farms were identical indicating that MRSA are transmitted between farms through the purchase of colonized pigs. Two SCCmec types were found among the MRSA: type IV and type V. SCCmec type V was predominant. On two farms MRSA isolates with ST398, the same spa-type but with different SCCmec types (IV and V) were found, suggesting that different SCCmec elements have been inserted into MSSA with the same genotype. All MRSA strains were resistant to tetracycline, but additional resistances to erythromycin, lincomycin, kanamycin and gentamicin were also found. All MRSA isolates were negative for the exfoliative toxin genes (eta and etb), PVL toxin genes (lukF and lukS), toxic shock syndrome gene (tst-1), and the leukotoxin genes (lukE, lukD, lukM, lukF').
本研究的主要目的是调查不同类型的猪场，如产仔猪场和育肥猪场，是否在耐甲氧西林金黄色葡萄球菌（MRSA）向荷兰育肥猪场的传播中起作用。研究纳入了12个产仔猪场、11个育肥猪场、6个从产仔到育肥一体化猪场、1个饲养猪场和1个人工授精中心。对这31个猪场的310头猪进行筛查，结果显示35头猪（11%）鼻腔携带MRSA。在31个被调查猪场中的7个（23%）发现有猪被MRSA定植，包括3个育肥猪场、3个产仔猪场和1个从产仔到育肥一体化猪场。猪使用标准抗菌药物似乎是MRSA携带的一个危险因素。对为MRSA阳性猪场供应猪的6个猪场的猪进行筛查发现，除一个猪场外，其他所有猪场的猪都是MRSA阳性。基因分型显示，所有MRSA菌株使用SmaI限制性内切酶通过脉冲场凝胶电泳（PFGE）无法分型，且多位点序列类型（MLST）为ST398。发现了不同的spa型，包括t011、t108、t567、t899和t1939，但在流行病学相关猪场的spa型是相同的，这表明MRSA是通过购买被定植的猪在猪场之间传播的。在MRSA中发现了两种葡萄球菌盒式染色体 mec（SCCmec）类型：IV型和V型。V型SCCmec占主导。在两个猪场发现了具有ST398、相同spa型但SCCmec类型不同（IV型和V型）的MRSA分离株，这表明不同的SCCmec元件已插入到具有相同基因型的甲氧西林敏感金黄色葡萄球菌（MSSA）中。所有MRSA菌株对四环素耐药，但也发现了对红霉素、林可霉素、卡那霉素和庆大霉素的额外耐药性。所有MRSA分离株的剥脱毒素基因（eta和etb）、杀白细胞素毒素基因（lukF和lukS）、中毒性休克综合征基因（tst-1）和白细胞毒素基因（lukE、lukD、lukM、lukF'）均为阴性。
