Isolation of mycoplasmas from lungs by a perfusion technique

Comparison of Chalquest and Hayflick media, with and without ammonium reineckate, for isolating Mycoplasma pulmonis from rats

Chalquest and Hayflick media with and without ammonium reineckate were compared for isolation of Mycoplasma pulmonis from the nasopharyngeal ducts, tracheobronchial trees, and middle ears of 66 naturally infected rats. The results show that 92% (366 of 396) of the samples were positive for M. pulmonis in Chalquest medium with and without ammonium reineckate and 66% (260 of 396) were positive in Hayflick medium with and without ammonium reineckate (P less than 0.001). An enhancing effect of ammonium reineckate on M. pulmonis isolation was observed only in Hayflick medium; the isolation rate was 76% (151 of 198) in Hayflick medium with ammonium reineckate as compared with 55% (109 of 198) in Hayflick medium without ammonium reineckate (P less than 0.03). No significant differences in isolation rates were observed between Chalquest medium with and without ammonium reineckate. The mean growth time of M. pulmonis on Chalquest medium was 3.4 days as compared with 5.1 days in Hayflick medium, indicating that M. pulmonis can be detected earlier on Chalquest medium than on Hayflick medium. These data indicate that Chalquest medium is superior to Hayflick medium for M. pulmonis isolation from rats.

Capsular material of Mycoplasma gallisepticum and its possible relevance to the pathogenic process

A ruthenium red-staining capsule was observed on two pathogenic strains, but not on one nonpathogenic strain of Mycoplasma gallisepticum. The capsule appeared to mediate cytadsorption of mycoplasmas to the chicken tracheal epithelium without evidence of membrane fusion. No relationship was seen between the presence of capsule and hemagglutination titers of the strains examined.

Protective effect of vaccines on Mycoplasma pulmonis-induced respiratory disease of mice

Mice inoculated intranasally with either a virulent or an avirulent strain of live Mycoplasma pulmonis were resistant to respiratory disease induced by a subsequent intranasal challenge with virulent organisms. Similarly, mice inoculated intravenously with the virulent strain were resistant to intranasal challenge with the same strain. In contrast, mice inoculated intravenously with avirulent M. pulmonis were not resistant to intranasal challenge with the virulent mycoplasma strain. Studies on mice inoculated intravenously with the two strains of M. pulmonis indicated that persistance of mycoplasmas in the respiratory tract may be important in inducing resistance to intranasal challenge with M. pulmonis. These observations, together with the lack of correlation between the level of serum antibodies and resistance to M. pulmonis-induced respiratory disease, suggested that local immune mechanisms were important in resistance. It is proposed that an effective vaccination schedule to protect mice against M. pulmonis-induced respiratory disease may be one that stimulates both systemic and local immune defenses. This suggestion is supported by the observation that systemic followed by local administration of inactivated M. pulmonis was more effective in inducing resistance in mice to intranasal challenge with live organisms than was systemic administration alone. In addition, mice inoculated solely by the intranasal route with inactivated mycoplasmas were resistant to M. pulmonis-induced respiratory disease. These studies indicate the importance of local defense mechanisms in the induction of resistance to M. pulmonis-induced respiratory disease in mice.

Pneumonia in mice produced by Neisseria gonorrhoeae

Gonococci of colony type 1 were introduced by intranasal inoculation into the lungs of mice in an attempt to produce infection. The organisms were eliminated from the three strains of mice used within 24 hours of challenge. Cyclophosphamide treatment of mice failed to render them susceptible although the organisms disappeared more slowly. The lungs of immunologically normal animals that had received either viable or heat-killed gonococci were acutely inflamed with infiltration of bronchioles and alveoli by polymorphonuclear and mononuclear leucocytes. Most of the changes had resolved after about four days. In cyclophosphamide-treated mice pulmonary infiltration by polymorphonuclear leucocytes was not evident, suggesting that these cells were not primarily responsible for the clearance of the gonococci. Despite the failure to produce a sustained infection, this model may be valuable for studying the local inflammatory effect of gonococcal endotoxin.

Effect of immunosuppression on arthritis in mice induced by Mycoplasma pulmonis

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