A Dilution Plate Counting Method for Certain Strains of Bacterium tularense

Abstract

Turbidimetry and titration of virulence for animals have constituted the only methods available for assaying cultures or suspensions of Bacterium tularense.

Influence of Bacterial Infection on Serum Enzymes of White Rats

“…The low-virulent Jap strain of F. tularensis, isolated from a human lymph node in 1926 in Japan, was used for preparation of killed cell suspensions. The organisms were grown in an incubator-shaker for 18 to 24 hr at 35 C in the broth medium of Snyder et al (23). Cultures were adjusted to contain 1% formaldehyde and allowed to stand overnight at room tempera-ture.…”

The Relative Errors of Bacteriological Plate Counting Methods

“…The inoculum was distributed by means of a sterile, bent glpss rod. This method has been used routinely with Bacterium tularnse (Snyder, Engley, Penfield, and Creasy, 1946) and is a modification of the method of Anderson and Stuart (1935).…”

“…These figures, like all the data presented, are exclusive of any eriror contributed by the process of preparing dilutions. In the case of an organism apparently characterized by a larger variability, as for example Bacterium tularense (Snyder, Engley, Penfield, and Creasy, 1946), the reduction of the standard error would be more impressive. It is recognized that frequently practical limitations with respect to the number of plates inoculated are set by considerations of economy instead of manipulative convenience, so that the foregoing recommendations may well be referred principally to studies in which precision is of especial importance, rather than to routine practice.…”

Studies on Tularemia

“…All plate counts were made on glucose-cysteine-blood 297 on September 21, 2020 by guest http://jb.asm.org/ Downloaded from MAX D. MOODY AND CORA M. DOWNS agar (GCBA) (Downs et al, 1947a). Colonial morphology was observed on GCBA and on Snyder's agar (Snyder et al, 1946a), which contained. 1 per cent dextrose.…”