Gajewska Joanna, Chajęcka-Wierzchowska Wioleta
Department of Industrial and Food Microbiology, University of Warmia and Mazury in Olsztyn, Plac Cieszyński 1, 10-726 Olsztyn, Poland.
Pathogens. 2020 Aug 14;9(8):654. doi: 10.3390/pathogens9080654.
The capacity for biofilm formation is one of the crucial factors of staphylococcal virulence. The occurrence of biofilm-forming staphylococci in raw milk may result in disturbances in technological processes in dairy factories as well as the contamination of finished food products. Therefore, this study aimed to determine the prevalence and characteristics of staphylococcal biofilm formation in raw milk samples and to explore the genetic background associated with biofilm formation in those isolates. The material subjected to testing included 30 cow's milk samples acquired from farms in the central part of Poland. A total of 54 staphylococcal strains were isolated from the samples, of which 42 were classified as coagulase-negative (CoNS) staphylococci belonging to the following species: , , , , , , , and , while 12 were classified as . The study examined the isolates' capacity for biofilm formation and the staphylococcal capacity for slime production and determined the presence of genetic determinants responsible for biofilm formation, i.e., the A, D, and and, additionally, among coagulase-negative staphylococci, i.e., the , , , P and E. Each tested isolate exhibited the capacity for biofilm formation, of which most of them (79.6%) were capable of forming a strong biofilm, while 5.6% formed a moderate biofilm, and 14.8% a weak biofilm. A capacity for slime production was demonstrated in 51.9% isolates. Most of the tested staphylococcal strains (90.7%) had at least one of the tested genes. Nearly half (47.6%) of the CoNS had the gene, while for , the gene was demonstrated in 58.3% isolates. The frequency of the gene occurrence was 23.8% and 25% in CoNS strains and , respectively. The gene was demonstrated in only three CoNS isolates. The presence of the A was only demonstrated in CoNS strains (24.1%), while the D was found in both CoNS strains (21.4%) and (100%). Among the CoNS, the presence of the P (16.7%), (28.6%) and E (23.8%) was demonstrated as well. The obtained study results indicate that bacteria of the spp. genus have a strong potential to form a biofilm, which may pose a hazard to consumer health.
生物膜形成能力是葡萄球菌毒力的关键因素之一。生牛奶中形成生物膜的葡萄球菌的出现可能会导致乳制品工厂工艺过程的紊乱以及成品食品的污染。因此，本研究旨在确定生牛奶样品中葡萄球菌生物膜形成的流行情况和特征，并探索这些分离株中与生物膜形成相关的遗传背景。测试材料包括从波兰中部农场采集的30份牛奶样品。从这些样品中总共分离出54株葡萄球菌菌株，其中42株被归类为凝固酶阴性（CoNS）葡萄球菌，属于以下物种： 、 、 、 、 、 、 、 和 ，而12株被归类为 。该研究检测了分离株的生物膜形成能力和葡萄球菌产生黏液的能力，并确定了负责生物膜形成的遗传决定因素的存在，即A、D、 和 ，此外，在凝固酶阴性葡萄球菌中，即 、 、 、P和E。每个测试的分离株都表现出生物膜形成能力，其中大多数（79.6%）能够形成强生物膜，而5.6%形成中度生物膜，14.8%形成弱生物膜。51.9%的分离株表现出产生黏液的能力。大多数测试的葡萄球菌菌株（90.7%）至少有一个测试基因。近一半（47.6%）的CoNS有 基因，而对于 ，58.3%的分离株有 基因。CoNS菌株和 中 基因出现的频率分别为23.8%和25%。仅在三株CoNS分离株中检测到 基因。A的存在仅在CoNS菌株中得到证实（24.1%），而D在CoNS菌株（21.4%）和 （100%）中均被发现。在CoNS中，也证实了P（16.7%）、 （28.6%）和E（23.8%）的存在。获得的研究结果表明， 属的细菌具有很强的形成生物膜的潜力，这可能对消费者健康构成危害。
