In vitro culture of tetrathyridia of Mesocestoides corti using a gel based diphasic medium

Tetrathyridia of Mesocestoides corti were cultured in vitro in a diphasic medium consisting of a liquid medium (CMRL Sigma) and a thixotropic nutrient gel (Oxoid). Tests demonstrated that a 50% medium/gel mixture produced optimum conditions for the survival and development of tetrathyridia. Established anthelminthic drugs were inoculated into the gel which demonstrated that this system can be used for preliminary anthelminthic drug screening. The development and survival of the tetrathyridia were influenced by the addition of pepsin, trypsin and liver peptone to the culture media. The development and maturation of proglottids were observed in addition to asexual reproduction by the process of budding. Tetrathyridia maintained in vitro and reinfected into both mouse and rat hosts retained their viability.

Comparison of the sensitivity of two methods for isolation of Mycoplasma pneumoniae

Throat swab specimens from 1,494 Marine Corps recruits were inoculated into vials containing diphasic (broth/agar) mycoplasma medium and also onto PPLO agar plates, which were subsequently overlayed with sheep erythrocytes in saline agar. Strains of Mycoplasma pneumoniae were isolated from 89 (6%) of the specimens by one or both of the methods. Eight-one of the 89 (91%) positive specimens were cultured with diphasic medium, whereas only 42 (47%) were cultured with the overlay method (x2 = 7.44, P less than 0.01). The diphasic system for isolation of M. pneumoniae should be the method of choice in clinical and research application.

Evaluation of a microscopy method for rapid detection and identification of Mycoplasma pneumoniae

A microscopy test that used the typical shape of Mycoplasma pneumoniae cells growing on glass was investigated for its value for diagnostic purposes. Suspensions from 108 throat swabs were infected artificially with 102, 103, and 104 colony-forming units of three M. pneumoniae strains per ml. Agar medium, a diphasic medium, and the microscopy method with liquid medium in cover slip chambers were compared for isolation of the mycoplasmas. The mycoplasms were detected first by the microscopy method in nearly all concentrations tested. Typical M. pneumoniae cells could often be detected after 48 h. No differences were found between a laboratory strain and two low-passage strains. The experimental results suggest that under special circumstances the microscopy method could be a useful tool for isolation and identification of M. pneumoniae.

The growth of an axenic strain ofEntamoeba invadensin different media

The growth of an axenic strain ofEntamoeba invadensin two media (Trypticase–liver broth and Trypticase–Panmede) is compared with that of a monobacterial strain in diphasic medium supplemented with starch. The axenic strain multiplied more slowly, and produced lower yields of amoebae than the monobacterial strain.Amoebae multiplied more rapidly and produced higher yields in Trypticase–liver broth than in Trypticase–Panmede.The effect of certain variations in the basic Trypticase–Panmede medium was investigated. Serum stimulated the growth of the axenic strain in Trypticase–Panmede, so that although the initial multiplication rate was not increased, the maximum yields of amoebae were increased to levels that varied according to the concentration of the serum.The multiplication of the axenic amoebae was depressed by procedures which probably aerated the medium.I thank Dr L. S. Diamond for axenic strain NIH:200 ofE. histolytica, and Professor E. Meerovitch for axenic strain PZ ofE. invadens. I am much indebted to Dr P. Whittlestone, of the Department of Animal Pathology, Cambridge, who examined cultures of strain N for the presence of mycoplasmata. The work was carried out while the author was a member of the scientific staff, Medical Research Council.