Bovine mastitis has been a concern for dairy herd for decades. The adaptation capacity of one of the main species responsible for this disease, Staphylococcus aureus (S. aureus), plays a pivotal role in this issue. The aim of this study was to establish a molecular and phenotypic profile of 285 S. aureus strains isolated from milk of subclinical mastitis cows from 18 different farms in São Paulo State using spa typing, multilocus sequence typing (MLST), pulsed field gel electrophoresis (PFGE), agr cluster (I, II, III and IV) typing, PCR for genes including enterotoxins (sea, seb, sec, sed, see, seg, seh, sei), toxic shock syndrome toxin (tsst-1), and Panton-Valentine leucocidin (pvl), as well as in vitro resistance assays for 12 antibiotics. The results showed a wide variety of strains with a high toxigenic potential; concomitantly, sec, seg and seh were prevalent. In addition, we observed a predominance of the spa types t605 (ST 126, CC126) and t127 (ST1, CC1) and the unusual presence of t321 causing bovine mastitis, which has been previously reported only in swine. The most frequent ST were ST126 (70.5%) and ST1 (10.5%). Regarding PFGE, we observed four major groups and six profile patterns. The highest resistance was observed for streptomycin (9.5%), followed by tetracycline (3.5%), clindamycin (9.3%), and erythromycin (2.8%). The tsst-1 gene was detected in 36.8% of isolates and pvl was not observed. One hundred and thirty-six (47.7%) isolates possessed agr type II, followed by types III (20%) and I (8.1%), with type IV not being detected. We observed that the same spa type could result in different PFGE profiles, so the exclusive use of spa type sequences can lead to incorrect interpretations regarding the spread of clones in an epidemiological context.

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Cross-contamination is one of the main factors related to foodborne outbreaks. This study aimed to analyze the cross-contamination process of Salmonella enterica serovar Enteritidis from poultry to cucumbers, on various cutting board surfaces (plastic, wood, and glass) before and after washing and in the presence and absence of biofilm. Thus, 10 strains of Salmonella Enteritidis were used to test cross-contamination from poultry to the cutting boards and from thereon to cucumbers. Moreover, these strains were evaluated as to their capacity to form biofilm on hydrophobic (wood and plastic) and hydrophilic materials (glass). We recovered the 10 isolates from all unwashed boards and from all cucumbers that had contacted them. After washing, the recovery ranged from 10% to 100%, depending on the board material. In the presence of biofilm, the recovery of salmonellae was 100%, even after washing. Biofilm formation occurred more on wood (60%) and plastic (40%) than glass (10%) boards, demonstrating that bacteria adhered more to a hydrophobic material. It was concluded that the cutting boards represent a critical point in cross-contamination, particularly in the presence of biofilm. Salmonella Enteritidis was able to form a biofilm on these three types of cutting boards but glass showed the least formation.

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The objectives of this study were to estimate the accuracy of Somaticell (Idexx Laboratories Inc., Westbrook, ME), California Mastitis Test (CMT), and microbiological examination of composite milk (MEC) to diagnose Streptococcus agalactiae intramammary infections (IMI), and to assess the agreement between Somaticell and CMT to detect these infections. A secondary objective was to estimate quarter- and cow-level prevalence of S. agalactiae IMI in the herds included in the study. Seven farms were included in the study. The CMT was performed and aseptic milk samples were collected from all quarters of all lactating cows. Composite milk samples were produced in the laboratory by mixing milk from all quarters of each sampled cow. The Somaticell test was performed on a subset of S. agalactiae-positive (n = 167) and S. agalactiae-negative (n = 152) quarter milk samples. Microbiological examination of quarter milk samples (MEQ) was considered the reference test for diagnosing S. agalactiae IMI. The accuracy of all tests at various thresholds was estimated using Bayesian latent class models. Apparent prevalence of S. agalactiae IMI was 15.8% (n = 184/1,164) at the quarter level (based on MEQ) and 28.5% (n = 83/291) at the cow level (based on MEC). True prevalence, as determined by Bayesian models, was 13.0% [95% credible interval (CR): 6.4-24.4%] at the quarter level, and 25.6% (95% CR: 15.3-39.5%) at the cow level. At the cow level (n = 285), sensitivity and specificity of MEC were 95.6 and 99.5%, respectively. The accuracy of Somaticell (n = 319 quarters) to identify S. agalactiae-infected quarters was 75.4, 86.4, 88.9, 89.4, and 91.0% at thresholds of 98,000, 147,000, 205,000, 244,000, and 282,000 cells/mL, respectively. The accuracy of CMT was 87.6, 90.7, 90.8, and 87.4% at thresholds of trace, 1, 2, and 3, respectively. The areas under the receiver operating characteristic curve for Somaticell and CMT were 94.5% (95% confidence interval: 91.8-97.2%) and 92.0% (88.6-95.4%), respectively. At the tested thresholds, the sensitivity of Somaticell ranged from 94.9 to 99.5% to detect S. agalactiae IMI, and specificity ranged from 48.1 to 87.1%. The sensitivity of Somaticell at the lowest threshold (69,000 cells/mL; sensitivity = 99.9%; 95% CR: 98.2-100%) was higher than that of CMT at any tested threshold. Results of this study could be used at the farm level to reduce the use of antimicrobials and reach specific goals in S. agalactiae eradication programs.

The Minas fresh cheese is a fresh and moist cheese and, therefore, has a short shelf-life. The use of raw milk as the main feedstock, the absence of ripening and the facility of contamination are factors that can compromise the product’s microbiological quality. The aim of this study was to describe the hygienic-sanitary quality of 50 Minas fresh cheeses marketed in Botucatu city, São Paulo, Brazil, close to their production date, and another 50 units from the same lot exactly on the expiration date, according to the Brazilian Sanitary Surveillance Agency (ANVISA). We also searched for enterotoxins genes in Staphylococcus aureus and its in vitro expression. In 36% of the first analyzed samples, the count of coliforms at 45ºC was above the limit and, as for the second analysis, 44%. Regarding coagulase positive staphylococci, 10 (20%) samples showed concentration above the permitted by law next to the production date and 14% on the expiration date. Salmonella was only observed in one sample analyzed near the date of production, while L. monocytogenes only in one sample analyzed on the expiration day. We isolated three enterotoxigenic strains of S. aureus that produced Staphylococcal Enterotoxin B (SEB) and Staphylococcal Enterotoxin C (SEC) in vitro, highlighting the importance of proper storage of this product due to its potential to cause intoxication. Overall, the quality of Minas fresh cheese is still unsatisfactory, leading to risks to consumers’ health.

Staphylococcus aureus can elicit mild to more severe degrees of mastitis in cattle, depending on the response of the host's immune system and the virulence factors of the specific isolate. Several virulence factors are controlled by a global regulatory system, designated accessory gene regulator (agr). Thus, the objective was to examine associations between different capsular and agr types and the severity of bovine mastitis caused by S. aureus. All isolates were obtained from bovine subclinical (n = 50), mild clinical (n = 73), and moderate clinical mastitis cases (n = 28). Isolates containing the agrI gene and lacking the agr locus (agr − ) were more prevalent among subclinical than clinical mastitis cases, whereas isolates containing the agrII and agrIII genes were more prevalent among clinical mastitis cases. The capsular types 5 (cap5) and 8 (cap8) were found in 42 and 44%, respectively, of the isolates obtained from subclinical cases and in 38.6 and 58.4%, respectively, of those isolated from clinical mastitis cases. Capsular type was not associated with type of mastitis (subclinical, mild clinical, or moderate clinical). We found a strong association between agr type and type of mastitis, suggesting that knowledge of S. aureus genetic profiles could be an additional tool to control this disease.

This study aimed to evaluate the modifying effects of dietary genistein (GEN) and indole-3-carbinol (I3C) on early mammary gland development in female Sprague-Dawley offspring born to mothers exposed to BPA during gestation. Pregnant rats were treated with BPA25 or 250 μg/kg bw/day from gestational days 10 to 21 with or without dietary intake of GEN (250 mg/kg chow) or I3C (2000 mg/kg chow). At post-natal day (PND) 21, female offspring from different litters were euthanized for mammary gland development and gene expression analyses. Our results indicated that prenatal exposure to BPA25 and 250 did not modify the ductal elongation of the mammary gland tree or the estrogen receptor alpha (ER-α) expression in terminal end buds (TEBs). However, BPA25exposed offspring had a higher number of terminal structures (TEBs + TDs) and an increased mammary branching and cell proliferation index in TEBs. Besides that, BPA25 and 250 modulated the expression of several genes in the immature mammary gland that were not changed in a dose dependent manner and involved different clusters of up-and down-regulated genes. Furthermore, BPA25 and BPA250 + I3C-treated groups also had a higher number of enriched functional gene categories. In addition, maternal dietary GEN and I3C in association with BPA exposure produced specific gene expression alterations in the mammary gland and overcome the adverse effect of BPA25, decreasing the branching of the mammary gland. In conclusion, prenatal BPA exposure induced both morphological and gene expression modifications on the mammary gland that dietary intake of GEN and I3C reverted on BPA25-exposed animals.