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C C SHEPARD

Publications and source records attributed to C C SHEPARD.

At least 19 recordsLinked to original sources
PubMed1965

MYCOBACTERIUM LEPRAE IN MICE: MINIMAL INFECTIOUS DOSE, RELATIONSHIP BETWEEN STAINING QUALITY AND INFECTIVITY, AND EFFECT OF CORTISONE.

Shepard, Charles C. (Communicable Disease Center, U.S. Public Health Service, Atlanta, Ga.), and Dorothy H. McRae. Mycobacterium leprae in mice: minimal infectious dose, relationship between staining quality and infectivity, and effect of cortisone. J. Bacteriol. 89:365-372. 1965.-The minimal infectious dose of Mycobacterium leprae in mouse foot pads was found to be on the order of 10 solidly staining bacilli. In a titration experiment, the actual number found was 3.4 to 34 solid bacilli, and the order of magnitude was confirmed by experience with inocula containing varying numbers of solidly staining leprosy bacilli from mouse passage and from clinical sources. The acid-fast staining quality of leprosy bacilli was related in a useful way to the subsequent rate at which bacillary growth appeared. When the proportion of solidly staining bacilli was high, the calculated generation time was shortest, and the lower the proportion, the longer the generation times. The results were in accord with the hypothesis that all viable bacilli are solid, and that when they die, most of them become nonsolid. Varying proportions of the dead bacilli, perhaps up to 10%, remain solid, at least temporarily. The growth curve of M. leprae in mice was followed in several experiments with total counts of acid-fast bacteria and determination of the ratio of solid bacilli. What had been called a maximal stationary phase was seen to consist of sequential phases of conversion of solid to nonsolid bacilli (death), reappearance of solid bacilli (growth), and conversion of solid to nonsolid bacilli (death). When cortisone was administered, leprosy bacilli grew somewhat more slowly during the logarithmic phase, but attained a higher level, especially of solidly staining bacilli.

Animals↗
PubMed1963

IMMUNOLOGICAL IDENTIFICATION OF FOOT-PAD ISOLATES AS MYCOBACTERIUM LEPRAE BY LEPROMIN REACTIVITY IN LEPROSY PATIENTS.

Lepromin, a product containing Mycobacterium leprae from patients' tissues, fails to elicit skin reactions in lepromatous patients; this non-reactivity was utilized as a means of identifying the mycobacterium isolated in mouse foot-pads from leprosy patients. To do this a suspension of acid-fast bacilli prepared from mouse foot-pads infected with a typical isolate was compared to human lepromin. The isolate was in fourth passage, and the multiplication since first isolation had diluted the original inoculum to insignificant levels. Three preparations were tested: A, A foot-pad preparation containing 1.6 x 10(7) organisms/ml, B, lepromin diluted to the same bacillary content, and C, undiluted lepromin containing 4.2 x 10(7) organisms/ml. The reactions were compared in 34 lepromatous and 30 tuberculoid patients. All 34 lepromatous patients were negative in both early (Fernandez) and late (Mitsuda) reactions to all 3 antigens. In the tuberculoid patients the late reactions were positive in 66.7, 70.0 and 90.0 per cent to antigens A, B, and C, respectively. The size of the reactions to A and B were closely correlated in the individual patients. Experience in leprosy patients with suspensions prepared from 16 other mycobacterial cultures is reported or reviewed. None of them produced reactions that correlated with those of lepromin. Thus the lack of reactivity to lepromin of lepromatous patients appears to be a specific phenomenon. The results provide evidence that the foot-pad isolates and M. leprae are immunologically identical.

Animals↗
PubMed1963

EFFECT OF ENVIRONMENTAL TEMPERATURES ON INFECTION WITH MYCOBACTERIUM MARINUM (BALNEI) OF MICE AND A NUMBER OF POIKILOTHERMIC SPECIES.

Clark, H Fred (Communicable Disease Center, Atlanta, Ga.), and Charles C. Shepard. Effect of environmental temperatures on infection with Mycobacterium marinum (Balnei) of mice and a number of poikilothermic species. J. Bacteriol. 86:1057-1069. 1963.-An exploration was made of the effect of environmental temperature on infections with Mycobacterium marinum of mice, young opossums, and bats, and of 50 species of poikilothermic animals. In artificial medium (7H9 broth) M. marinum grew most rapidly from 25 to 35 C, with generation times of 4 to 6 hr. At 37 C, the generation time was 14 hr; at 20 C, 20 hr; and, at 15 C and lower, little growth was observed. In mice, deep body temperatures were found to be 36.5 to 37.3 C at environmental temperatures of 4 to 30 C. At an environmental temperature of 34 C, they averaged 39.1 C; at 37 C they averaged 40.2 C. Foot-pad temperatures were within a few degrees of ambient temperatures from 10 to 34 C. In mouse foot-pad infections, the optimal environmental temperature for infection was 20 C, and the generation time of the infecting bacilli at this environmental temperature was about 15 hr. Intravenously inoculated mice developed peripheral infections of nose, feet, and tail at environmental temperatures of 4 to 30 C. At these temperatures, they had severe pneumonic involvement, and the mice at lower temperatures tended to succumb most rapidly to systemic infection. At 34 C, the intravenously infected mice did not develop peripheral infections and there was no pulmonary involvement. Young opossums, whose deep body temperatures are only 34 to 36 C, were inoculated in the foot-pad and intravenously. Foot-pad infection developed without systemic involvement. Bats, which assume environmental temperature when at rest, were inoculated in the foot-pad. Foot-pad infections were observed but no systemic disease. The bats could be maintained for only short periods, however. Poikilothermic animals were studied. Deep body temperatures were found to be nearly identical with ambient temperature. A total of 50 species of reptiles, amphibians, and fish were infected intraperitoneally in a number of experiments, as animals were available. Susceptibility to M. marinum was found throughout these species. There was no tendency to peripheral involvement. In experiments to determine the optimal environmental temperature for infection, cricket frogs (Acris), American chameleons (Anolis), young garter snakes (Thamnophis), and the young of three species of turtles were inoculated intraperitoneally. The optimal temperature for infection was found to be 30 C in each case, and infections at 20 C were definitely slower. The generation time of M. marinum in American chameleons at 30 C was about 19 hr; at 20 C, it was about 46 hr; and, at 10 C, the bacilli did not apparently multiply. Transmission studies revealed instances where infected animals shed M. marinum into the waters in which they were kept, and where animals became infected from water containing M. marinum.

Amphibians↗
PubMed1958

A comparison of the growth of selected mycobacteria in HeLa, monkey kidney, and human amnion cells in tissue culture.

HeLa, monkey kidney, and human amnion cells in tissue cultures were compared as sites for the multiplication of strains of tubercle bacilli or original and reduced pathogenicity, and for several other species of mycobacteria capable of causing disease in humans. The arrangement of the pathogenic species inorder of their growth rates in HeLa cells was Mycobacterium fortuitum, Mycobacterium balnei, and the "yellow bacillus," followed closely by the tubercle bacillus. This order was also correct for these species in monkey kidney and human amnion cells, and is the same as that seen in bacteriological media. The arrangement of the strains of tubercle bacilli in order of their growth rates in all three types of cells was: H37Rv, then R1Rv, and lastly H37Ra, which multiplied about as slowly as BCG. An INH-resistant strain grew about as rapidly as H37Rv. Growth of the pathogenic species occurred at about the same rates in HeLa and monkey kidney cells, but was distinctly slower in human amnion cells, which are less active metabolically. Irradiation of the cells in doses up to 5000 r did not affect the subsequent growth of mycobacteria in them. Preliminary experiments with human leprosy bacilli indicate that they can be introduced into these cells in high numbers and that the bacilli then persist for the life of the cells.

Amnion↗