Cariogenic actinomyces identified with a beta-glucosidase-dependent green color reaction to Gardenia jasminoides extract.

The oral bacteria Actinomyces naeslundii and Actinomyces viscosus are known to contribute to the initiation and progression of human dental caries, especially root caries. We report that both A. naeslundii and A. viscosus react with a component in the Gardenia jasminoides extract to produce a distinct green product. This green color reaction was found to be dependent on the bacterial beta-glucosidase. The reaction is specific for cariogenic actinomyces, and it can detect as few as 10(4) cells of A. naeslundii and A. viscosus per ml.

beta-Lactamase producing bacteria in adult periodontitis.

In 23 untreated adult periodontitis patients, the occurrence of beta-lactamase producing periodontal bacteria was determined. In addition to non-selective isolation media, selective isolation and growth of beta-lactamase positive subgingival bacterial species was carried out on blood agar plates supplemented with amoxicillin and plates with amoxicillin+clavulanic acid. Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, Peptostreptococcus micros, Fusobacterium nucleatum, Bacteroides forsythus and Campylobacter rectus isolates from the non-selective medium were tested for beta-lactamase activity by a nitrocefin disk method (DrySlide) and by a laboratory chromogenic nitrocefin-based test. Isolates from the amoxicillin plates that were absent on the amoxicillin/clavulanic acid plates were identified and tested for beta-lactamase production. Based on the non-selective plates, six of 23 P. intermedia isolates, 2 of 19 B. forsythus isolates and 3 of 23 F. nucleatum isolates were beta-lactamase positive. The beta-lactamase positive species Prevotella loescheii, Prevotella buccae, Prevotella buccalis and Actinomyces spp were recovered from the selective amoxicillin plates. beta-Lactamase positive subgingival species were recovered from 17 of 23 patients (74%) but usually comprised low proportions of the subgingival microbiota (range < 0.01-15%). Comparison of the DrySlide test and the nitrocefin-based laboratory test revealed full agreement of test results. beta-Lactamase activity in whole subgingival plaque was detected in 12 patient samples (52%). It was concluded that beta-lactamase activity in subgingival bacteria in adult periodontitis is a common feature. However, since the majority of the samples showed only low-level enzymatic activity, the clinical relevance of this observation with regard to therapy with unprotected enzyme-susceptible beta-lactams is uncertain, though failure on the other hand, is difficult to rule out when a mechanism of resistance is present. The majority of beta-lactamase positive strains was found among species of the Prevotella genus.

[Anti-influenza effect of bacterial RNAse and the pharmacokinetic basis of its administration in experimental studies]. / Protivogrippoznoe deistvie bakterial'noi RNKazy v éksperimente i farmakokineticheskoe obosnovanie sposoba vvedeniia ee v organizm.

Anti-influenzal action of bacterial and pancreatic RNAases was studied. It was shown in ovo that the RNAases had distinct virus inhibiting activity with respect to various strains of the grippe A virus and did not practically differ by their activity from remantadin but unlike it had inhibitory action on the grippe B virus. The anti-influenzal activity of bacterial RNAase in contrast to pancreatic one was detected not only in experiments with developing chick embryos but also in albino mice with lethal influenzal infection. The index of the animal protection by the preparation amounted to 54-90 per cent depending on the virus infecting dose and RNAase administration route, the lifespan of the animals being increased by 2.4 to 3.8 days. It was shown that the anti-influenzal effect of bacterial RNAase correlated with high levels of the exogenic enzyme in blood of the animals after the preparation intravenous administration. Elimination of RNAase was observed already within the first 4 hours after the experiment start. Intranasal administration allowed to increase the residence time of RNAase in blood up to 8 hours at the account of its gradual absorption from the administration site and the preparation availability increased more than 2-fold. The results provided the basis for recommending the intranasal route of bacterial RNAase administration for use in further investigation of RNAase antiviral activity.

Evaluation of human oral organisms and pathogenic Streptococcus for production of IgA protease.

IgA protease is a proteolytic enzyme found in whole human saliva and in dental plaque that cleaves both secretory and myeloma IgA of human origin to yield intact Fabalpha and Fcalpha fragments. To determine which bacteria are capable of producing this enzyme, we have examined a variety of strains normally found in the human oral cavity and a number of streptococci of known Lancefield group serotype. Streptococci of groups A, B, C, D, F, G, H, M, and N, Streptococcus mutans, Streptococcus sanguis, Streptococcus mitior, Streptococcus salivarius, Streptococcus faecalis, Veillonella, Lactobacillus, Actinomyces, Propionibacterium, Bacteroides, and Fusobacterium were grown in liquid medium, and fluids were examined for IgA protease activity. Only S. sanguis and clinically isolated group H streptococci elaborated IgA protease under the culture conditions used. Negative strains could not be stimulated to produce the enzyme when cultured in the presence of secretory IgA. Among the natural oral bacteria, capacity to produce IgA protease is restricted to certain species of Streptococcus, notably those of the group H serotype. Since secretory immunity is mediated by the IgA class of antibody, the presence of this enzyme at mucosal surfaces could modify the secretory immune function.