Detection of staphylo-coagulase using plasmas from various animals

The effect of sources of Staphylococcus aureus and plasmas, concentration of plasma, temperature and duration of incubation on coagulase-test results was evaluated. Using S. aureus strains of food origin, the value of plasmas in coagulase tests was, in order of superiority, human and rabbit greater than pig greater than donkey greater than chicken greater than cattle greater than duck greater than goat greater than dog. However, with staphylococcal isolates of animal origin the order was cattle greater than pig greater than human greater than duck greater than goat greater than dog greater than rabbit greater than chicken greater than donkey. Regardless of the source of staphylococci, horse plasma was found unsuitable in coagulase tests as it clotted spontaneously. The temperature (25 and 37 degrees C), and duration of incubation and type of anticoagulant had no significant (P greater than 0.05, X2) effect on coagulase-test results. It is concluded that in testing staphylococcal isolates from various sources for coagulase production, it is imperative to use plasmas from several animal species whenever practicable as staphylococcal biotypes display variable ability to coagulate different plasmas.