Summary. Three hundred and sixty-seven strains of pioneer streptococci isolated from the mouths of 40 healthy, full-term infants during the first month of life were examined by two taxonomic schemes that incorporated biochemical and physiological characteristics, IgAl protease production and glycosidase activities. Streptococcus mitis biovar 1 and S. oralis comprised 55-0 YO of the pioneer streptococci isolated from neonates. S. salivarius constituted 25.3% of the isolates, while S. anginosus, S. mitis biovar 2, S. sanguis and S. gordonii accounted collectively for 1 1.4 % . Difficulties in identifying streptococci were encountered and 8.4% of the 367 isolates could not be assigned to a recognised species.
Cellular DNA from 25 Actinomyces naeslundii and Actinomyces viscosus strains belonging to the 7 taxonomic clusters of Fillery et al. (1978) and several unclustered strains was obtained by enzymatic and N-lauroylsarcosine/guanidine isothiocyanate treatment of whole cells, followed by extraction of the nucleic acid. The DNA samples were digested with restriction endonucleases BamHI or PvuII, and agarose gel electrophoresis was used to obtain DNA fingerprints. The DNA fragments were subjected to Southern blot hybridization with a digoxigenin-labeled cDNA probe transcribed from Escherichia coli 16S and 23S rRNA. The patterns of bands from genomic (DNA fingerprints) and rDNA fingerprints (ribotypes) were used for comparison between the taxonomic cluster strains and strains within clusters. Representative strains from each taxonomic cluster provided different BamHI DNA fingerprints and ribotype patterns with 3 to 9 distinct bands. Some strains within a cluster showed identical ribotype patterns with both endonucleases (A. naeslundii B120 and A. naeslundii B102 from cluster 3), while others showed the same pattern with BamHI but a different pattern with PvuII (A. naeslundii ATCC 12104 and 398A from cluster 5). A viscosus ATCC 15987 (cluster 7) and its parent strain T6 yielded identical fingerprint and ribotype patterns. The genomic diversity revealed by DNA fingerprinting and ribotyping demonstrates that these techniques, which do not require phenotypic expression, are suited for study of the oral ecology of the Actinomyces, and for epidemiological tracking of specific Actinomyces strains associated with caries lesions and sites of periodontal destruction.
As part of a longitudinal study of the relationship between bacterial colonization and the secretory immune response, 367 isolates of pioneer viridans streptococci collected from 40 breast-and bottle-fed neonates within the first month postpartum were tested for the production of immunoglobulin Al (IgAl) protease and glycosidases. Fifty percent of the streptococci isolated produced IgAl protease, including all isolates of Streptococcus oralis and S. sanguis, 60.7% of S. mitis biovar 1 isolates, and some isolates that could not be identified. Three cleavage patterns of oil heavy chains were observed. Six isolates of S. mitis biovar 1 that did not produce IgAl protease attacked the oxl chain. Incubation of IgAl protease-negative S. mitis biovar 1 isolates with IgAl, either prior to or together with S. sanguis, rendered the IgAl paraprotein resistant to cleavage by the IgAl protease of S. sanguis. The ability of some pioneer streptococci in the human oral cavity to produce IgAl protease and of others to modify the susceptibility of IgAl to cleavage by IgAl protease perhaps enhances their ability to survive in this habitat.
PTSD with secondary psychotic symptoms was not associated with familial psychosis, suggesting it does not reflect the presence of an underlying psychotic disorder.
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