The production of DNase was determined by addition of aliquots
of 1 ml of the isolates in drops on the DNase test agar surface with
toluidine blue at 0.1%, the plates were then incubated at 37 C for
48 h. Positive result for the presence of DNase was indicated by the
formation of rosy halos around the colonies.
For the coagulase test, 0.3 mL of each culture of isolates was
transferred to sterile tubes containing 0.3 mL of rabbit plasma
(plasma-Coagu LaborClin) and incubated at 36 C ± 1 C for 6 h. The
formation of a large and organised clot or total coagulation was
considered a positive result for the test.