Maria das Graças Xavier de Carvalho

Occurrence of enterotoxin-encoding genes in Staphylococcus aureus causing mastitis in lactating goats

Staphylococcal enterotoxins are the leading cause of human food poisoning worldwide. Staphylococcus spp. are the main mastitis-causing agents in goats and frequently found in high counts in goat milk. This study aimed to investigate the occurrence of enterotoxin-encoding genes in Staphylococcus aureus associated with mastitis in lactating goats in Paraiba State, Brazil. Milk samples (n=2024) were collected from 393 farms. Staphylococcus aureus was isolated in 55 milk samples. Classical (sea, seb, sec, sed, see) and novel (seg, seh, sei) enterotoxin-encoding genes were investigated by means of polymerase chain reaction (PCR). From thirty-six tested isolates, enterotoxin-encoding genes were detected in 7 (19.5%) S. aureus. The gene encoding enterotoxin C (seC) was identified in six isolates, while seiwas observed in only one isolate. The genes sea, seb, sed, see, seg and seh were not observed amongst the S. aureus investigated in this study. In summary, S. aureus causing mastitis in goats can harbor enterotoxin-encoding genes and seC was the most frequent gene observed amongst the investigated isolates. This finding is important for surveillance purposes, since enterotoxin C should be investigated in human staphylococcal food poisoning outbreaks caused by consumption of goat milk and dairy products.

Soroepidemiologia da leptospirose e brucelose bovina em propriedades rurais de agricultura familiar do agreste paraibano, Nordeste do Brasil

The aim of this investigation was to determine the frequency of positive herds and seropositive animals to bovine leptospirosis and brucellosis in family farm rural properties from the mesoregion of the State of Paraiba, as well as to identify risk factors. Blood samples were collected from 771 animals from 130 herds in five municipalities. For the serological diagnosis of leptospirosis, the microscopic agglutination test (MAT) using 24 Leptospira spp. serovars as antigens was carried out, and for brucellosis the Rose-Bengal Test (RBT) was used as screening test and the 2-mercaptoethanol test (2-ME) to confirm. For leptospirosis, the frequency of positive herds and seropositive animals was 18.4 and 3.6%, respectively; for brucellosis, 7.7% of the herds and 1.9% of the animals were positive. The most frequent Leptospira spp. serovar was Hardjo. Bovine purchase was identified as a risk factor to bovine brucellosis (odds ratio = 5.25; p = 0.044). The need for adoption and/or intensification of control and prevention measures was suggested in order to avoid economic losses and the transmission of the agents to humans, as well as the purchase of animals with known sanitary conditions.