FURTHER STUDIES OF A DIFFERENTIAL CULTURE TECHNIQUE FOR ESTIMATIONS OF ACIDOGENIC BACTERIA IN SALIVA

II. SPECIES OF LACTOBACILLI ISOLATED FROM SALIVA AND THEIR DISTRIBUTION IN A GROUP OF CHILDREN

¹ Dental and Medical Schools of Northwestern University, Departments of Bacteriology and Experimental Medicine, Chicago, Ill.

The predominant species of lactobacillus in the salivas of children was the strongly acidogenic L. casei, which was present alone or with other species in 88 per cent of the 45 children with high lactobacillus counts.

Gas-producing lactobacilli were present in more than half of the children, occasionally alone, but more commonly with other species. The production of gas in the Snyder test is an indication of their presence. L. fermenti was the most frequently encountered of the heterofermentative lactobacilli, being present in more than 40 per cent of the 45 children with high lactobacillus counts. Gas-producing lactobacilli in pure culture often do not produce a 4+ reading on Snyder's medium, even in 72 hours.

Lactobacillus acidophilus was isolated from only a small percentage of the children and only from tomato agar plates. This species is not sufficiently acidogenic to produce any appreciable change of color in Snyder's test or any cleared zones on DST medium.

A number of lactose-negative lactobacilli were isolated which were distinct from the two lactose-negative species already known (L. leichmannii and L. delbrucekii). They resembled L. casei in all respects except in the failure to ferment lactose.

This article has been cited by other articles:

				E. Simelyte, M. Rimpilainen, L. Lehtonen, X. Zhang, and P. Toivanen Bacterial Cell Wall-Induced Arthritis: Chemical Composition and Tissue Distribution of Four Lactobacillus Strains Infect. Immun., June 1, 2000; 68(6): 3535 - 3540. [Abstract] [Full Text] [PDF]