Tuberculosis. Bacteriology, Pathology and Laboratory Diagnosis

Baldwin, Edward R.; Petroff, S. A.; Gardner, Leroy S.

doi:10.1097/00007611-192706000-00043

Cited by 6 publications

(3 citation statements)

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“…The progenitors of some of today's enumeration techniques go back to the days when Robert Koch incorporated agar-agar into plating media (26). A number of enumeration protocols still popular at present were developed decades ago, such as direct counting (3,7) and the most-probable-number technique (10,23). Although these techniques are routinely used, they have a number of limitations (8) and are often extremely labor-intensive.…”

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confidence: 99%

Enumeration and biomass estimation of bacteria in aquifer microcosm studies by flow cytometry

DeLeo¹,

Baveye²

1996

Appl Environ Microbiol

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Flow cytometry was used to enumerate and characterize bacteria from a sand column microcosm simulating aquifer conditions. Pure cultures of a species of Bacillus isolated from subsurface sediments or Bacillus megaterium were first evaluated to identify these organisms' characteristic histograms. Counting was then carried out with samples from the aquifer microcosms. Enumeration by flow cytometry was compared with more-traditional acridine orange direct counting. These two techniques gave statistically similar results. However, counting by flow cytometry, in this case, surveyed a sample size 700 times greater than did acridine orange direct counting (25 l versus 0.034 l) and required 1/10 the time (2 h versus 20 h). Flow cytometry was able to distinguish the same species of bacteria grown under different nutrient conditions, and it could distinguish changes in cell growth patterns, specifically single cell growth versus chained cell growth in different regions of an aquifer microcosm. A biomass estimate was calculated by calibrating the total fluorescence of a sample from a pure culture with the dry weight of a freeze-dried volume from the original pure culture. Growth conditions significantly affected histograms and biomass estimates, so the calibration was carried out with cells grown under conditions similar to those in the aquifer microcosm. Costs associated with using flow cytometry were minimal compared with the amount of time saved in counting cells and estimating biomass.

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confidence: 99%

Enumeration and biomass estimation of bacteria in aquifer microcosm studies by flow cytometry

DeLeo¹,

Baveye²

1996

Appl Environ Microbiol

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“…The avirulent strains of M . tuberculosis were maintained on Herrold's (1931) egg-yolk agar medium, containing 5 yo glycerol, and the virulent strain H37Rv on the surface of Proskauer & Beck's defined medium containing asparagine (see Baldwin, Petroff & Gardner, 1927). Well-grown cultures were ground in Griffith tubes to give aqueous suspensions equal in opacity (by eye) to a standard containing 0-2 mg. (wet-weight)/ml.…”

Section: Methodsmentioning

confidence: 99%

Changes in Morphology of an Avirulent Strain of Mycobacterium tuberculosis under the influence of Non-ionic Surface-active Agents

Hart¹,

Rees²

1954

Journal of General Microbiology

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SUMMARY: When the avirulent strain of Mycobactmiurn tuberculosis H37Ra was repeatedly subcultured in a liquid medium containing low concentrations of ' Triton A 20 ' or other chemically similar non-ionic surface-active polyoxyethylene ethem, the morphology changed from the amorphous growth pattern characteristic of avirulent tubercle bacilli to the formation of microscopic 'cords' similar to those shown by virulent strains such as H37Rv. Once developed, the cord-forming property of H37Ra persisted when cultures were transferred to liquid medium devoid of surface-active agent, even when such transfer was made after passage through mice ; after further subcultures, however, a tendency to reversion was apparent. No difference in virulence was detected between cord-forming H37Ra and the unmodified strain when tested in mice.Previous work had indicated that a lower member of the polyoxyethylene ether wries, the dimer ' D 4', inhibited amorphous-growing avirulent tubercle bacilli, including H 37 Ra, but not the growth of naturally cord-forming strains, exemplified by the virulent H37Rv and attenuated strains derived from it. The growth of cord-forming avirulent organisms, developed from H37 Eta in the present expedments, was also found to be relatively unaffected by D4.

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“…The doses were 10 -1, 10 -a, 10 -~, and 10 -6 rag. and represent respectively, according to Baldwin, Petroff, and Gardner (15) and Calmette (12), 5,000,000, 50,000, 500, and 50 bacteria. By this simple titration it was hoped that an end-point of dosage would be reached at which some animals would survive.…”

Section: Second Experiment--purposementioning

confidence: 99%

The Standardization of Longevity Against Dose in Experimental Tuberculosis by Intracerebral Inoculation

Smithburn

1936

Journal of Experimental Medicine

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Progress in experimental investigation of tuberculosis has been retarded by the chronicity of the disease and by the lack of regularity in the course pursued in experimental animals. Whereas in some other infectious diseases it has often been possible to control factors of dosage of culture and host resistance so that a standardized result was obtainable, such has not been the case in tuberculosis. Final results in animal experiments on tuberculosis have not been obtainable in less than a few months, and not infrequently a single experiment has covered a year or more. Thus, in our experience, in ten experiments including 120 rabbits, each inoculated intravenously with a standard dose of 0.1 nag. of B-1 bovine strain tubercle bacilli (then only moderately virulent) and subjected to no therapeutic procedure, the first animals succumbed in the 3rd week after inoculation (15 to 20 days) and several survived more than a year, while one animal lived 738 days. In nine of the ten experiments, maximum survival ranged from 290 per cent of minimum survival up to 4500 per cent. Our results with other, more virulent bovine strains and with the H-37 human strain have been similarly variable, although somewhat less so. Obviously such variations have made interpretation of results difficult and permitted unavoidable intercurrent factors to play a part in the end-result.In order to overcome these difficulties, Bogen (1) has adopted the procedure of killing all inoculated animals after about 90 days and making quantitative estimates of the amount of existing disease. Animals dying before this time were excluded as having died from or 771 on

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Tuberculosis. Bacteriology, Pathology and Laboratory Diagnosis

Abstract: Pp. xvi plus 242, with 4 coloured plates and 82 figures in the text. Price, 21s. net.

Cited by 6 publications

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Enumeration and biomass estimation of bacteria in aquifer microcosm studies by flow cytometry

Enumeration and biomass estimation of bacteria in aquifer microcosm studies by flow cytometry

Changes in Morphology of an Avirulent Strain of Mycobacterium tuberculosis under the influence of Non-ionic Surface-active Agents

The Standardization of Longevity Against Dose in Experimental Tuberculosis by Intracerebral Inoculation

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