Hippurate hydrolysis was used to accurately determine the presence of group B. A positive result, development and persistance of a precipitate, is an almost certain indicator of the presence of S. agalactiae. This test can be used together with the results of the CAMP reaction test to collectively ensure group B's isolation (1).
The bile esculin hydrolysis tests were used to distinguish group D streptococci. If the inoculated slants were found to have black growth through over half the tube the test is positive and indicates the presence of group D streptococci.
The salt tolerance test is used to distinguish between the two types of group D streptococci; the enterococci and the nonenterococci. Salt tolerance of the organism along with a BE-positive test indicates an enterococcus. A negative salt tolerance test indicates a nonenterococci.
Optochin susceptibility was used to differentiate between the viridans and pneumoniae streptococcal species. If resistance to the disk is determined, the streptococci is viridans (1).
The last test was the bile solubility test. If the tested organism was soluble in bile and along with that was also optochin-positive, the organism is likely S. pneumoniae (1).
The objective of this laboratory is to determine, through numerous physiological tests, the species of streptococci present in a sample from the pharynx and in three unknown samples (x,y,z). Also, to become familiar with the normal flora of streptococcal species found on the body and to become familiar with its related virulence or potential to cause harm for its host.
Materials and Methods:.
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The experiments completed were performed by following the procedures outlined on pages 29 through 43 and appendix C, pages 73 through 78 of the Laboratory Manual Biology 3523: Pathogenic Microbiology (1). .
Results:.
The pharyngeal isolates were examined on their respective blood agar streak stab plates to determine hemolysis.
