Bonsaglia Erika Carolina Romão, Rossi Rodolfo S, Latosinski Giulia, Rossi Bruna Fernanda, Campos Fernanda Cristina, Junior Ary Fernandes, Pantoja José Carlos F, Rall Vera Lucia Mores
Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil.
Department of Veterinary Hygiene and Public Health, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil.
Pathogens. 2023 Feb 14;12(2):311. doi: 10.3390/pathogens12020311.
() is one of the main agents that causes mastitis in dairy cows, mainly inducing the subclinical form, which is characterized by a high somatic cell count (SCC). The aim of this study was to correlate the increase in SCC caused by in cows with subclinical mastitis to the presence of genes related to adhesion and invasion in bovine mammary epithelial cells (BMEC) and biofilm formation. Considering the 145 isolates tested, 57.2% presented the capsular type Ia and 42.8% presented type III. We identified the virulence genes among the isolates and determined nine genetic profiles. The most common profile was identified in 69 isolates (47.5%): , , , , , , and . All isolates produced biofilm, with 58.6% classified as strong producers, 29% as moderate producers and 12.4% as weak producers. No statistical correlation was found between the presence of virulence genes and increased SCC or biofilm production. However, biological evidence was observed between increased SCC and biofilm production. One isolate from each profile was randomly subjected to adhesion and invasion assays, and all of them adhered to BEMC, but none were able to invade. Our results showed that different genetic profiles do not provide advantages for bacteria to invade BMEC in vitro. In addition, biofilm production appears to be related to high SCC.
（）是导致奶牛乳腺炎的主要病原体之一，主要引发亚临床型乳腺炎，其特征是体细胞计数（SCC）升高。本研究的目的是将亚临床型乳腺炎奶牛中由（）引起的SCC升高与牛乳腺上皮细胞（BMEC）中与黏附、侵袭及生物膜形成相关的基因存在情况相关联。在测试的145株分离株中，57.2%呈现Ia型荚膜，42.8%呈现III型荚膜。我们在分离株中鉴定了毒力基因并确定了9种基因谱。最常见的基因谱在69株分离株（47.5%）中被鉴定出来：（具体基因谱内容未给出）。所有分离株均产生生物膜，其中58.6%被归类为强生产者，29%为中度生产者，12.4%为弱生产者。在毒力基因的存在与SCC升高或生物膜产生之间未发现统计学相关性。然而，在SCC升高与生物膜产生之间观察到生物学证据。从每个基因谱中随机选取一株分离株进行黏附与侵袭试验，所有分离株均黏附于BEMC，但均未能够侵袭。我们的结果表明，不同的基因谱在体外并未为细菌侵袭BMEC提供优势。此外，生物膜产生似乎与高SCC相关。
