A strain of Trichomonas vaginalis , recently isolated from a patient afflicted with recurrent symptomatic trichomoniasis, showed resistance to metronidazole, tinidazole, and nimorazole in vitro as well as in vivo. In a serial dilution test using cysteine monohydrochloride-peptone-liver infusion-maltose medium, T. vaginalis IR-78 was only resistant under aerobic conditions. Under anaerobic conditions it was as susceptible as the normal reference strain. The minimal lethal concentrations of metronidazole, tinidazole, and nimorazole for IR-78 were 100, 50, and 50 ,ug/ml aerobically and 0.4,0.4, and 0.2 ,g/ml anaerobically, respectively.The efficacy of metronidazole, tinidazole, and nimorazole was assessed in vivo by oral administration to mice simultaneously infected with IR-78 both subcutaneously and intraperitoneally. The CD5o (dose needed to cure 50% of infections) of each compound was significantly higher for the subcutaneous than for the intraperitoneal infection. In contrast, there was little difference in CD50 for these infections in mice inoculated with a susceptible trichomonas strain. The CD50's for all three compounds against intraperitoneal and subcutaneous infections with IR-78 were 2 to >70 times higher than for susceptible strain E. Both forms of infection with IR-78 could always be cured with therapeutically acceptable doses of tinidazole and nimorazole; subcutaneous infections could not be cured with tolerated doses of metronidazole.
The porphyrin productions of P a.-strains, isolated on the one hand from inlfammatory acne lesions, on the other hand from sebaceous follicle filaments from 10 persons each were compared quantitatively and qualitatively, after the appropriate material had been pooled, With respect to the acne strains one could observe a somewhat increased porphyrin production as well as the discharging of a precentually greater portion of porphyrins to the surrounding material. When separated by TLC the acne material showed a more intense coproporphyrin band.
SUMMARY Culture samples of Neisseria gonorrhoeae and Escherichia coli were studied by transmission and electron microscopy to evaluate the effect of different preparation procedures on the pilation of these organisms. Unfixed as well as fixed bacteria showed only few, long, filamentous appendages when investigated in ultrathin sections, negatively stained specimens, or critical-point dried preparations. Snap-frozen specimens of E. coli showed many short and thin pili after being shadowed with carbon and platinum whereas those of N. gonorrhoeae showed only some type-C-like pili. Thus, the number and morphological appearance of pili appear to be greatly influenced by the preparation techniques used for study by electronmicroscopy. Conclusions as to the type and the infectivity of a bacterial strain can, therefore, not be based on purely morphological criteria.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.