Characterization of staphylococci

Abstract

A total of 158 Staphylococcus strains from various sources were characterized by biochemical, physiological, and morphological tests. Numerical taxonomy was applied by using these features. Taxonomic analysis was done with programs run under the MVS-TSO system of the IBM 370 complex and PDP-10 system of the National Institutes of Health. DNA-DNA hybridization with nitrocellulose filters was done to compare selected atypical cultures with American Type Culture Collection reference strains. We found that the use of the nomenclature of Bergey's Manual (8th edition) to identify these strains by species was not adequate. DNA homology values supported the formation of Staphylococcus hyicus subsp. hyicus separate from Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus saprophyticus. The three tests that best separated these strains into four species were (i) tube coagulase (6-h or 24-h porcine plasma or 24-h Difco rabbit plasma), (ii) production of acetoin or acid aerobically from ribose, maltose, or trehalose, and (iii) growth in the presence of novobiocin. Four strains of S. hyicus subsp. hyicus (VII76, VII113, VII131, and VA519) gave typical enterotoxigenic responses in monkey-feeding tests but were negative for enterotoxins A through E, suggesting the presence of one or more new enterotoxins. Two coagulase-negative, heat-stable DNase-positive strains (D143 and ARM) could not be classified by either DNA-DNA hybridization or numerical taxonomy, and D143 was enterotoxigenic as measured by the monkey-feeding bioassay. DNA homology showed that strain FRI-698M was more closely related to S. epidermidis than to S. aureus, yet it produced enterotoxin D. These data suggest the occurrence of coagulase-negative enterotoxigenic strains that are not S. aureus; nonetheless, a positive tube coagulase test and heat-stable DNase test should together be useful for routine screening of most potentially enterotoxigenic staphylococci in foods.

Isolation and characterization of staphylococci from goats milk produced in Northern Ireland

“…In addition, other staphylococcal species besides Staph. aureus may produce $ Communicating author enterotoxin (Hoover et al 1983) and thus may also pose a public health hazard.…”

Resistance to quaternary ammonium compounds in Staphylococcus spp. isolated from the food industry and nucleotide sequence of the resistance plasmid pST827

“…aureus. More recently enterotoxin production has also been demonstrated in a number of other species (Hoover et al 1983;Hirooka et al 1983;Valle et al 1990;Bautista et al 1988). In addition, coagulase-negative staphylococci are regarded as possible genetic reservoirs of resistance (Jaffe et al 1982;Pfaller and Herwaldt 1988), with the potential to in staphylococci isolated from the meat and poultry industries.…”

Comparison of Reverse Passive Latex Agglutination Test and Immunoblotting for Detection of Staphylococcal Enterotoxin a and B

“…SEs are resistant to inactivation by gastrointestinal proteases such as pepsin. Heat stability is one of the most important physical and chemical properties of SEs in terms of food safety (Denny et al 1971;Humber et al 1975;Lee et al 1977;Hoover et al 1983).…”