Three beta-streptococci serogrouping kits, Phadebact, SeroSTAT, and Streptex, were evaluated as to their sensitivity, accuracy, and suitability as methods for serogrouping streptococci in a clinical microbiology laboratory. The majority of the primary isolates examined by the various methods associated with each of the three kits were correctly identified. The Streptex direct mixed-culture procedure was more often associated with the observation of cross-reactivity than with the direct procedures of the other two kits which did not employ mixed growth cultures. Furthermore, the Streptex kit was associated with more falsenegative responses than those determined by the other two kits under evaluation. These results appeared to be due to the relatively poor sensitivity of the Streptex grouping reagents. The Streptex test procedures required more labor than the other kit procedures, requiring a 1-h enzymatic extraction step for the release of the group antigens. The SeroSTAT kit provided only a direct procedure and, thus, is limited in its application. The Phadebact procedures were the most versatile by providing not only a direct and a 24-h grouping procedure, but also by including a 4-h method that may be employed as required by the clinical microbiologist.

Using the indirect fluorescein-labeled and indirect peroxidase-antiperoxidaselabeled immunohistochemical techniques, and utilizing both antiserum specific for the f8-subunit of choriogonadotropin and antiserum for the total hormone, we have demonstrated the presence of a choriogonadotropin-like immunoreactive material in a strain of Eubacterium lentum that was originally isolated from a rectal tumor. In contrast, both immunohistochemical reactions were negative when applied to a strain of Corynebacterium parvum and to pathogenic and nonpathogenic strains of Agrobacterium tumefaciens. Our results demonstrate for the first time the expression of the choriogonadotropin-like antigen in an obligate anaerobe and support our previous findings that the choriogonadotropinlike material appears to be expressed only in "cancer-associated bacteria" but that not all bacteria associated with the malignant neoplasms have the capacity to express the antigen, at least in amounts detectable by immunohistochemistry.

The presence of choriogonadotropin-like material and its intimate association with the membranes of the wall of bacteria isolated from cancer patients, has been demonstrated by immuno-electron microscopy utilizing the indirect peroxidase-antiperoxidase-labeled antibody technique. The bacteria were an Escherichia coli strain isolated from a carcinoma of colon, and ATCC 25559 strain of Eubacterium lentum, an anaerobic microorganism originally isolated from a rectal tumor.