Prevalence and expression of staphylococcal enterotoxin genes in<i>Staphylococcus aureus</i>isolated from food poisoning outbreaks

Bastos, Caroline Peixoto; Bassani, Milena; Mata, Marcia Magalhães; Lopes, Graciela Völz; Silva, Wladimir Padilha da

doi:10.1139/cjm-2017-0316

Cited by 17 publications

(11 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although tsst is mainly detected in SAU, the presence of this gene in NAS has been reported (39, 109). Enterotoxins and staphylococcal exotoxins, identified originally from SAU, have been studied extensively in staphylococcal isolates originating from humans (110, 111) and animals (108, 112, 113) and in animal-derived food products (114–116). Enterotoxins produced by some staphylococcal species, apart from interrupting host immune responses, also cause food poisoning.…”

Section: Discussionmentioning

confidence: 99%

Comprehensive Virulence Gene Profiling of Bovine Non- aureus Staphylococci Based on Whole-Genome Sequencing Data

et al. 2019

View full text Add to dashboard Cite

Non-aureus staphylococci (NAS) are the most frequently isolated pathogens from intramammary infection (IMI) in dairy cattle. Virulence factors (VFs) and mechanisms by which NAS cause IMI are not fully known. Herein, we analyzed the distribution of 191 VFs in 441 genomes of 25 NAS species, after classifying VFs into functional categories: adherence (n = 28), exoenzymes (n = 21), immune evasion (n = 20), iron metabolism (n = 29), and toxins (n = 93). In addition to establishing VF gene profiles, associations of VF genes between and among functional categories were computed, revealing distinctive patterns of association among VFs for various NAS species. Associations were also computed for low, medium, and high somatic cell count (SCC) and clinical mastitis (CM) isolates, demonstrating distinctive patterns of associations for low SCC and CM isolates, but no differences between high SCC and CM isolates. To determine whether VF distributions had any association with SCC or CM, various clustering approaches, including complete linkages, Ward clustering, and t-distributed stochastic neighbor embedding, were applied. However, no clustering of isolates representing low SCC, medium SCC, or high SCC or CM was identified. Regression analysis to test for associations with individual VF functional categories demonstrated that each additional toxin and host immune evasion gene increased the odds of having high SCC or CM, although an overall increase in the number of VFs was not associated with increased SCC or occurrence of CM. In conclusion, we established comprehensive VF gene profiling, determined VF gene distributions and associations, calculated pathogenic potentials of all NAS species, and detected no clear link between VF genes and mastitis. IMPORTANCE Non-aureus staphylococci (NAS) are the most frequently isolated pathogens from milk in dairy cattle worldwide. The virulence factors (VFs) and mechanisms by which these bacteria cause udder infection are not fully known. We determined the distribution and associations of 191 VFs in 25 NAS species and investigated the relationship between VFs and disease. Although the overall number of VFs was not associated with disease severity, increasing numbers of toxin and host immune evasion genes specifically were associated with more severe disease outcomes. These findings suggest that the development of disease and the interactions of VFs with the host are complex and determined by the interplay of genes rather than just the presence of virulence genes. Together, our results provide foundational genetic knowledge to other researchers to design and conduct further experiments, focusing on understanding the synergy between VFs and roles of individual NAS species in IMI and characterizing species-specific effects on udder health.

show abstract

Section: Discussionmentioning

confidence: 99%

Comprehensive Virulence Gene Profiling of Bovine Non- aureus Staphylococci Based on Whole-Genome Sequencing Data

et al. 2019

View full text Add to dashboard Cite

show abstract

“…However, a recent study of Fursova et al (2018) reported the production of SEA, SEC, SEE, and SEG in higher proportions by S. aureus isolated from subclinical mastitis. On the contrary, the most common enterotoxin produced by S. aureus involved in food poisoning outbreaks is SEA (Bastos et al, 2017). Many possible explanations exist for the different rates of enterotoxin production reported in the different studies (Cretenet et al, 2011).…”

mentioning

confidence: 99%

Short communication: Characterization of enterotoxin-producing Staphylococcus aureus isolated from mastitic cows

Grispoldi

Massetti

Sechi

et al. 2019

Journal of Dairy Science

View full text Add to dashboard Cite

Staphylococcus aureus is not only a common cause of bovine mastitis, but also an agent of food poisoning in humans. In an attempt to determine whether staphylococci causing bovine mastitis could also cause food poisoning, 60 isolates of presumed S. aureus were isolated in the period between March and August 2017 from 3,384 routine, composite, quarter milk samples of individual cows raised on 12 dairy farms in central Italy. Seventeen out of 60 isolates were confirmed as S. aureus after coagulase, thermonuclease, and biochemical tests. These isolates were analyzed by PCR for the presence of the nuc, sea, seb, sec, sed, and see genes. The positive isolates were nuc, 100% (17); sea, 35.29% (6); seb, 5.88% (1); sec, 5.88% (1); sed, 29.41% (5); and see, 47.06% (8). The isolates were also tested with 2 enzyme immunoassay diagnostic kits, one for the screening detection of the production of staphylococcal enterotoxins (SEA, SEB, SEC, SED, SEE) and one for the detection of specific enterotoxin produced by each isolate. Seven out of 17 (41.18%) were enterotoxin producers: 7 produced SEA (41.18%), 1 SEB (5.88%), 1 SEC (5.88%), 5 SED (29.41%), and 6 SEE (35.29%). To further characterize the isolates, they were analyzed by the Kirby Bauer test for susceptibility to 13 antimicrobials (ampicillin, ciprofloxacin, kanamycin, tetracycline, gentamicin, methicillin, nalidixic acid, erythromycin, amoxicillin/ clavulanic acid, streptomycin, vancomycin, neomycin, and enrofloxacin), and we detected resistance to ampicillin (52.94%), nalidixic acid (70.59%), erythromycin (5.88%), and amoxicillin/clavulanic acid (17.65%). The isolates were sensitive to the main classes of antimi-crobials used for the treatment of bovine subclinical mastitis. The presence of enterotoxin-producing isolates of S. aureus in bovine milk means that a temperature abuse or a breakdown in the thermal treatment of the milk could present a food safety risk, particularly if all enterotoxigenic isolates could potentially produce SEA in milk.

show abstract

“…A recent study conducted in one of the Asian countries i.e., Bangladesh found that 69.7% of isolated strains (from pure colonies) were positive for at least one enterotoxin gene, with one amongst them even presenting a combination of six genes (pvl, sea, seb, sec, sed and see) ( 22 ). On the contrary, Bastos ( 23 ) reported that the most common enterotoxin of S. aureus involved in the food poisoning outbreaks is the sea . The differences in the isolation of enterotoxins may be due to the differences in the ecological reservoirs of S. aureus in different countries and regions of the world.…”

Section: Discussionmentioning

confidence: 99%

Phenotypic and Molecular Characterization of Bovine Mastitis Milk Origin Bacteria and Linkage of Intramammary Infection With Milk Quality

et al. 2022

View full text Add to dashboard Cite

Mastitis is a multi-etiological complex disease of dairy cows and negatively affects the quality and quantity of milk. Milk is a nutritious food for human being; milk quality is negatively affected by intramammary infection of dairy cows. A total of 300 milk samples were collected from mastitis dairy cows irrespective of parity and stage of lactation, 235 (78.33%) samples were culturally positive and yielded 1,100 bacterial isolates. Staphylococcus aureus was found to be the prime etiological agent involved in the mastitis of dairy cows, followed by Escherichia coli and other environmental pathogens. On the molecular characterization of isolates obtained from the milk culture, various toxic genes such as nuc, seb, hla, stx1, stx2, hly, and Sagl were found on different isolated bacteria. Milk somatic cell counts (SCC) were found to be directly related to the severity of mastitis. On drawing the SCC correlation with milk components, it was found that SCC had a significant negative correlation with fat, lactose, solid not fat (SNF), and ash. It was concluded that mastitis-affected milk contains numerous pathogenic bacteria, toxins, and reduced milk quality, which is unfit for human consumption.

show abstract

Prevalence and expression of staphylococcal enterotoxin genes inStaphylococcus aureusisolated from food poisoning outbreaks

Cited by 17 publications

References 33 publications

Comprehensive Virulence Gene Profiling of Bovine Non- aureus Staphylococci Based on Whole-Genome Sequencing Data

Comprehensive Virulence Gene Profiling of Bovine Non- aureus Staphylococci Based on Whole-Genome Sequencing Data

Short communication: Characterization of enterotoxin-producing Staphylococcus aureus isolated from mastitic cows

Phenotypic and Molecular Characterization of Bovine Mastitis Milk Origin Bacteria and Linkage of Intramammary Infection With Milk Quality

Contact Info

Product

Resources

About