Toxin Genes and Other Characteristics of Staphylococcus aureus Isolates from Milk of Cows with Mastitis

Abstract

In the present study, 103 Staphylococcus aureus strains isolated from milk samples from 60 cows with mastitis from eight different farms in seven different locations in one region of Germany were compared pheno-and genotypically and by identification of various toxins. On the basis of culture and hemolytic properties and by determination of the tube coagulase reaction, all of the isolates could be identified as S. aureus. This could be confirmed by PCR amplification of species-specific parts of the gene encoding the 23S rRNA. In addition, all of the S. aureus isolates harbored the genes encoding staphylococcal coagulase and clumping factor and the genes encoding the X region and the immunoglobulin G binding region of protein A. These four genes displayed size polymorphisms. By PCR amplification, the genes for the toxins staphylococcal enterotoxin A (SEA), SEC, SED, SEG, SEI, SEJ, and TSST-1 but not those for SEB, SEE, SEH, and the exfoliative toxins ETA and ETB could be detected. To analyze the epidemiological relationships, the isolates were subjected to DNA fingerprinting by macrorestriction analysis of their chromosomal DNAs. According to the observed gene polymorphisms, the toxin patterns, and the information given by macrorestriction analysis of the isolates by pulsedfield gel electrophoresis, a limited number of clones seemed to be responsible for the cases of bovine mastitis on the various farms.

Pheno- and Genotyping of Staphylococcus aureus Isolates of Sheep Origin

“…Many authors studied the production of exfoliative toxins among S. aureus isolates from bovine mastitis and have reported a rare prevalence of these toxins (Hayakawa et al 2000;Akineden et al 2001;Larsen et al 2002;Endo et al 2003). The present study confirms that these genes are rare in S. aureus isolates from sheep; eta and etb genes were not found in any of our isolates.…”

“…A high co-occurrence between sec and tst has also been reported for bovine S. aureus strains (Akineden et al 2001;Stephan et al 2001;Zschock et al 2004). Smyth et al (2005) published a high prevalence (19.2%, 46.2% and 60.9%) of the tst gene in bovine, goat and sheep isolates, respectively.…”

“…The presence of sea, seb, sed, see and tst genes in S. aureus strains associated with bovine mastitis has been described earlier (Akineden et al 2001;Stephan et al 2001;Scherrer et al 2004;Zschock et al 2004;Morandi et al 2007). Of the staphylococcal enterotoxin encoding genes, the sec gene has been reported to have the highest frequency in bovine as well as ovine isolates (Scherrer et al 2004).…”

Occurrence and antibiotic resistance of enterotoxigenic Staphylococcus aureus in raw ovine and caprine milk in Greece

“…None of our CM isolates carried the seb gene. Similarly, several studies reported that none of the strains isolated from bovine and CM and dairy products harbored the seb gene (Akineden et al 2001;Lyra et al 2013). In other studies, however, the seb gene was detected in S. aureus isolates from milk and dairy products at various frequencies (Jørgensen et al 2005;Zouharova and Rysanek 2008).…”

Prevalence and Multiplex PCR for Enterotoxin Genes of Staphylococcus aureus Isolates from Subclinical Mastitis and Kareish Cheese

“…In generally, early study of [8] reported that 14% to 40% of all human food poisoning outbreaks were associated with staphylococcal enterotoxins, that manifested at first by sudden onset of fever, vomiting, nausea, abdominal cramps and diarrhea [9,10]. The existence of some virulence factors as enzymes, toxins, surface antigens, and capsule have an important role in S. aureus pathogenicity as in intramammary infection, it depends on the induction of immunosuppression [11] through stimulating of the proinflammatory cytokines and T-cell that evoked the inflammatory features. One of these factors is enterotoxins which proved to be more tolerance to pasteurization and higher temperature [12].…”