No abstract

Plaque samples from 22 ulcerated sites in eight patients with ANUG were cultured using quantitative anaerobic procedures and were examined microscopically. The partial characterization of the predominant cultivable flora revealed a constant flora comprised of a limited number of bacterial types and a variable flora composed of a heterogeneous array of bacterial types. This constant flora would appear to be pathognomonic of acute necrotizing ulcerative gingivitis (ANUG) and included the various Treponema and Selenomonas sp., which comprised about 32 and 6%, respectively, of the microscopic count; B. melaninogenicus ssp. intermedius and Fusobacterium sp., which averaged 24 and 3%, respectively, of the viable count. One week of metronidazole treatment caused a prompt resolution of clinical symptoms, which coincided with a significant reduction in the plaque proportions of the Treponema sp., B. melaninogenicus ssp., intermedius and Fusobacterium sp. for at least 2 to 3 months following treatment. Thus, the same anaerobic species which were numerically associated with the ANUG lesion were also selectively reduced in the plaque flora following resolution of the infection. This supports a role for the above species in the ulcerative stage of the lesion but does not demonstrate that these specific anaerobes initiated the infection. although not confirmed by the data, it was proposed that these particular anaerobic species gained ascendency in the plaque as a result of being selected through the availability of host-derived nutrients in individuals who had undergone certain physiological and psychological stresses.

A total of 80 oral strains of Bacteroides gingivalis, B. asaccharolyticus, B. melaninogenicus subsp. intermedius, B. melaninogenicus subsp. melaninogenicus, Capnocytophaga, Treponema denticola, and T. vincentii were characterized with the API ZYM system for 19 enzyme activities. Comparison of anaerobic and aerobic incubation with nine reference strains of these organisms showed no important differences. The key differential tests for black-pigmented Bacteroides strains and treponemes of oral origin were trypsin, a-glucosidase, and N-acetyl-13glucosaminidase. All Capnocytophaga strains produced distinctive aminopeptidase activities but varied in their glycosidic capabilities. The presence of a trypsin-like activity in B. gingivalis, T. denticola, and a group of Capnocytophaga strains may contribute to tissue destruction in periodontal disease.

An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to toxins A and B of Clostridium difficile was developed. Serum samples from 340 patients were tested for determination of the age-related prevalence of antitoxin. Antibody to toxin A was present in 64% of patients more than two years old and antibody to toxin B in 66% of patients more than six months old. A strongly positive ELISA value correlated with the presence of cytotoxicity-neutralizing antibody (P less than 0.001). Strongly positive ELISA values were obtained more commonly in convalescent sera from 16 patients with C difficile-induced colitis than in sera from the control population (antibody to toxin A, P less than 0.05; antibody to toxin B, P less than 0.001). Testing of paired sera revealed significant increases in the titer of IgG antibody to toxin A or B. Ten of the 16 patients with colitis had IgM titers of greater than or equal to 1:160 to one or both toxins. The data presented suggest that antibodies to toxins A and B are present in the majority of older children and adults and that patients with C difficile-induced disease develop serologic responses to one or both toxins.

We evaluated the effect of norfloxacin, 400 mg given orally every 12 hours, on the prevention of bacterial infections in 68 adult patients who had acute leukemia throughout prolonged courses of granulocytopenia (median, 32 days). Gram-negative infections were documented in 13 of the 33 patients receiving placebo, but only in 4 of the 35 patients receiving norfloxacin; no effect on the frequency of gram-positive or fungal infections was noted. Norfloxacin administration resulted in the suppression of gastrointestinal tract colonization by aerobic bacteria without the development of norfloxacin resistance. Patients receiving norfloxacin developed first infectious fevers later than did those receiving placebo, had more rapid resolution of that fever after systemic antibiotic treatment, and spent less time febrile. Therefore, although no difference was seen in survival duration, we found that the prophylactic administration of oral norfloxacin led to decreases in overall morbidity and gram-negative infections, was well tolerated, and did not predispose to the development of multiply drug-resistant bacteria.