Comparison of coagulase, deoxyribonuclease, and thermostable nuclease tests for identification of pathogenic Staphylococcus aureus
1981
Kim, J.M. | Song, H.J. | Jeong, O.B. (Chunpuk National Univ., Chunju (Korea R.). Coll. of Agriculture, Dept. of Veterinary Medicine)
A total of 251 clinical isolates (human origin 43 strains and boving udder origin 208 strains) of the Staphylococcus that fermented mannitol aerobically were tested for ability to produce coagulase, DNase, and thermostable nuclease. Of these, 158 isolates coagulated human or bovine plasma, produced DNase, and thermostable, nuclease and were identified as St. aureus, 146 of which produced a 1+ to 3+ clot. The remaining 12 isolated produced a -clot in citrate treated plasma but produced 1+ to 3+ clot in ethylenedi-aminetetraacetic acid (EDTA) treated plasma. It was found that 7 coagulase positive isolates failed to produce thermostable nuclease. In these organisms, we found out of the clot formation is not by coagulase activity but utilization of citrate, because EDTA treated plasma is not coagulated. Among 93 isolates which did not coagulate citrate-or EDTA treated plasma and thermostable nuclease negative, 28 strains produced DNase were identified as St. epidermidis, and other strains were not identification further. It was found that thermostable nuclease production appears to be a consistent property of St. aureus and the test is easy to perform, is rapid to become quite distinct within 2 to 4 hours, and is not influenced by as many factors and variations as the coagulase test.
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