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The authors conducted a study using surveillance monitoring methodology to identify operatory contamination and to evaluate the effectiveness of infection control procedures. Viridans streptococci were evaluated as biological indicators of oral contamination. Viridans streptococci, abundant in human saliva, were detected on operatory surfaces after dental treatments were finished and surfaces were disinfected. The findings validate current concepts of infection control as demonstrated in barrier methods.

Guinea pigs were sensitized to 3,4-benzo(a)pyrene, by epicutaneous application or by footbad injection in Freund's complete adjuvant. Conjugates of benzo(a)pyrene and guinea pig skin protein formed by ultraviolet radiation could elicit cutaneous delayed hypersensitivity and could inhibit the migration of macrophages obtained from guinea pigs sensitized to the carcinogen. Extracts of benzo(a)pyrene-treated guinea pig skin and conjugates formed in vitro with benzo(a)pyrene isocyanate were unable to consistently elicit delayed hypersensitivity reactions in vivo or in vitro. The results indicate a high degree of hapten-carrier specificity to contact sensitivity to benzo(a)pyrene.

The mutagenic activity of sidestream cigarette smoke particles was estimated by testing sidestream cigarette smoke particles which had been collected under controlled burning conditions in the laboratory. Two different extraction methods (Soxhlet and ultrasonic agitation) and 3 different solvents (dichloromethane, methanol, and acetone) were compared for their efficiencies in the extraction of compounds from sidestream cigarette smoke particles which are mutagenic in the Ames test. The mutagenic activity of the sidestream smoke particles was estimated to be 15,000-20,000 revertants per cigarette in TA98 with metabolic activation and 12,000-17,000 revertants per cigarette in TA100 without metabolic activation. Only weak mutagenic activity was detected in TA98 without activation and in TA100 with activation. Under test conditions used, ultrasonic agitation produced the most consistent results and acetone extraction produced the highest levels of mutagenic activity.

A spontaneously occurring stable deuterium-tolerant mutant was selected from highly virulent Pasteurella tularensis strain SCHU S4; the frequency of mutants in the cell populations was between 10(-3) and 10(-4). Upon cultivation of parent strain SCHU S4 in media containing D(2)O in lieu of H(2)O, inhibitory effects became manifest at 18% D(2)O and increased significantly beyond 54% D(2)O; mutant strain SCHU DT was not inhibited by media containing as much as 98% D(2)O. When cultivated in media containing D(2)O, mutant SCHU DT, in comparison with parent strain SCHU S4, showed a significant reduction in dermal and respiratory virulence for laboratory animals. Its immunogenic properties were comparable to viable P. tularensis vaccine strain LVS. Data on the comparative growth of various P. tularensis strains on media containing D(2)O suggested that "Old World" strains might be more tolerant to isotopic substitution of deuterium for protium than North American strains. Because of the residual virulence of SCHU DT for experimental animals it is believed to have limited value as a potential live vaccine strain.

Eigelsbach, H. T. (Fort Detrick, Frederick, Md.), J. J. Tulis, M. H. McGavran and J. D. White. Live tularemia vaccine. I. Host-parasite relationship in monkeys vaccinated intracutaneously or aerogenically. J. Bacteriol. 84:1020-1027. 1962.-Bacteriological, histological, immunohistochemical, and serological studies were made on monkeys administered live tularemia vaccine strain LVS by either of two routes. Comparative data are presented on nonvaccinated monkeys exposed via the respiratory route to a highly virulent strain of Pasteurella tularensis. Tissue changes resulting from either aerogenic or intracutaneous vaccination were mild, and consisted primarily of the proliferation of histiocytes without the formation of granulomas. The vaccine strain was isolated from the site of vaccination of animals inoculated dermally, from the lungs of animals vaccinated aerogenically, and from the regional lymph nodes, liver, and spleen of both groups; it was not isolated from the blood or bone marrow. Proliferation of the vaccine strain at the site of dermal inoculation and in the lungs of animals exposed aerogenically was observed within 24 hr; in both groups, the maximal viable population was reached within 3 days and maintained through the 10th day. A reduction in the number of viable vaccine organisms had begun by the 14th day; isolations were obtained only from the regional lymph nodes on the 28th day, and the vaccine strain was not isolated from any of the tissues cultured on the 90th day. Because the monkey is less resistant to tularemia than is man, the benign response of this animal to live tularemia vaccine indicates that the vaccine might also be safe for man when administered by either the dermal or respiratory route.