Congresso Brasileiro de Microbiologia 2023

Congresso Brasileiro de Microbiologia 2023

Resumo: 570-2

570-2

Staphylococcal enterotoxins play an important role in clinical and subclinical bovine mastitis.

Autores:

Stéfani Thais Alves Dantas (IBB-UNESP - Instituto de Biociências de Botucatu, FMVZ-USP - Faculdade de Medicina Veterinária e Zootecnia) ; Laura Tieme Suehiro Takume (FMVZ-UNESP - Faculdade de Medicina Veterinária e Zootecnia) ; Laura Beatriz Borim da Silva (IBB-UNESP - Instituto de Biociências de Botucatu) ; Bruna Fernanda Rossi (IBB-UNESP - Instituto de Biociências de Botucatu) ; Erika Carolina Romão Bonsaglia (IBB-UNESP - Instituto de Biociências de Botucatu) ; Ivana Giovannetti Castilho (IBB-UNESP - Instituto de Biociências de Botucatu) ; Ary Fernandes Júnior (IBB-UNESP - Instituto de Biociências de Botucatu) ; José Carlos de Figueiredo Pantoja (FMVZ-UNESP - Faculdade de Medicina Veterinária e Zootecnia) ; Juliano Leonel Gonçalves (CVM-MSU - College of Veterinary Medicine, Michigan State Universit) ; Marcos Veiga dos Santos (FMVZ-USP - Faculdade de Medicina Veterinária e Zootecnia) ; Vera Lúcia Mores Rall (IBB-UNESP - Instituto de Biociências de Botucatu)

Resumo:

Bovine mastitis is one of the most prevalent diseases in dairy cattle and causes significant economic losses to the global dairy industry. Staphylococcus aureus, a major pathogen causing contagious bovine mastitis, is frequently isolated from subclinical cases, although the clinical form also occurs, albeit less frequently. S. aureus possesses various virulence factors, including enterotoxins, which are crucial for its pathogenicity and can also cause foodborne poisoning. Importantly, these enterotoxins are thermoresistant and maintain their biological and immunological activities even after the pasteurization process. The objective of this study was to perform a comparative analysis of 206 isolates of S. aureus (103 isolated from cows with clinical mastitis and 103 from subclinical mastitis) regarding the presence of these enterotoxins and to determine if their presence plays a significant role in the signs of illness. We investigated previously described enterotoxins, including sea-see, seg-sez, sel26, sel27, se01, and se02. Among the isolates obtained from clinical mastitis, we observed the presence of up to 14 enterotoxin genes, with the most frequent being selw (99.03%), selx (78.64%), seh (50.48%), seg (16.5%), selm (15.53%), selu1 (10.68%), and sei (9.71%). In subclinical mastitis isolates, only five genes were found, namely selw (82.52%), selm (15.53%), selx (14.56%), seh (7.76%), and selz (3.88%). Statistical analysis using Fisher's exact test or chi-squared test revealed a significant difference (P < 0.0001) in the presence of the seg, seh, sei, selo, selu, selw, and selx genes. Other interesting findings were the limited number of genes in each isolate from subclinical mastitis (up to three genes), with the majority of isolates presenting only one gene (55/53.4%). On the other hand, among the clinical mastitis isolates, we observed up to nine genes in a single isolate (obtained from a severe case), with most cases presenting at least three genes (38/36.9%). Based on these results, we can conclude that enterotoxins indeed play an important role in the clinical signs of dairy cows with mastitis.

Palavras-chave:

Bovine mastitis, Enterotoxin, Staphylococcus aureus

Agência de fomento:

Processo n° 2021/09068-3, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)