DIFFERENTIAL-DIAGNOSIS BETWEEN STREPTOCOCCUS-AGALACTIAE AND LISTERIA-MONOCYTOGENES IN CLINICAL LABORATORY

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 7  (3) , 269-276
Abstract
Group B streptococci (S. agalactiae) and L. monocytogenes resemble each other in many morphological and biochemical characteristics. Ten .beta.-hemolytic strains of each species were subjected to 26 tests commonly and easily performed in the clinical laboratory. Macroscopic and microscopic morphology on solid media showed differences only in the size of the colonies and in the length of the individual organisms. Among many other tests, hippurate hydrolysis and the CAMP [Christie-Atkins-Munch-Petersen] reaction were positive in both species. In the presence of these two reactions, a negative catalase test and chaining in broth would make a presumptive diagnosis of S. agalactiae, while motility at 25.degree. C, the presence of the Henry effect and resistance to furadantin would be indicative of L. monocytogenes.