齧歯類のMycoplasmaに関する研究

Abstract

Biological characteristics, growth inhibition and double gel diffusion tests were studied on 115 strains of mycoplasmas isolated from 73 rats suffering from the chronic respiratory disease from five different colonies. Of the 115 strains, 31 were isolated from lung, 39 from bronchus, 41 from nose and 4 from mouth.One hundred and fourteen of the 115 strains were identified as Mycoplasma pulmonis, and the rest strain resembled to M. ahthritidis biologically, but did not show any characteristic correspondence to the species in growth inhibition test.They made large colonies (1 mm to 2 mm in diameter) on modified Edward's medium (AM-1) as reported previously. Central zones of standard strains, PG-22 and T, from mice were less remarkable, but that of rat strains were, generally, slightly remarkable. Surface of the colonies of rat strains were more granular and darker than the standard strains. They required serum for growth, did not grow at 22°C, produced “film and spots” on horse serum agar medium (AM-1), and were beta hemolytic with sheep and guinea pig erythrocytes and alpha hemolytic with horse erythrocytes. They grew well on agar medium aerobically and anaerobically. In semi-solid agar medium, they grew preferably near the surface. They reduced tetrazolium blue and methlene blue, and did not produce hydrogen sulfide and indole. The fermented glucose, mannose, maltose, glycogen and dextrin, but not galactose, lactose, sucrose, salicin and dulucitol. Variations of hemolysis and fructose were discussed. Production of “film and spots” was irregular according to cultural conditions.In growth inhibition test, some antisera did not inhibit or inhibited weakly the growth of heterologous strains, and one antiserum for strain R-1 inhibited the growth of homologous strains weakly and some heterologous strains strongly. Fifty-two out of 110 strains were inhibited by all of 6 anti-M. pulmonissera, but the remaining 58 strains were not inhibited by some of the antisera. Strain T was highly antigenic, that is, this strain was inhibited by all the 6 antisera, and antiserum of this strain inhibited all 110 strains. This may be one of the reasons why the strain PG-22 had not been identified as M pulmonisuntil quite recent days. This also indicates that adequate selection of standard strains in serological studies of Mycoplama must be done practically.By double gel diffusion test, using, the antisera that were absorbed with the liquid medium to remove the antibodies against the ingredients of this medium, especially horse serum, M. pulmonis was shown to have one to three common antigens. It was shown that there were some antigenic differences within M. pulmonis by growth inhibition and double gel diffusion tests.