A heat-labile sonic extract of a nonleukotoxic strain of Actinobacillus actinomycetemcomitans caused a dose-dependent inhibition of proliferation of human keratinocytes. Exposure of cells to heat-labile sonic extract for periods as brief as 10 min produced significant suppression of [3H]thymidine uptake 72 h later. I propose that alteration of epithelial barriers may be one pathogenic mechanism...

Serum IgG antibody titres to lipopolysaccharides (LPS) from two strains of Actinobacillus actinomycetemcomitans were significantly elevated in juvenile periodontitis compared with other types of periodontal disease and with controls (p less than 0.05). The highest antibody titres to Bacteroides gingivalis LPS were in juvenile periodontitis, but this difference was significant only against the c...

lacterial surface structures play a critical role in the initiation of infectious diseases. Various surface ^ components of pathogenic bacteria have been reported to be involved in host injury. There is a great deal of evidence incriminating certain Gram-negative, anaerobic bacteria present in the gingival crevice as etiologic agents of human periodontal diseases. We have isolated endotoxic cel...

Actinobacillus actinomycetemcomitans, an oral bacterium implicated in human periodontal disease, was recently demonstrated to invade cultured epithelial cells (D. H. Meyer, P. K. Sreenivasan, and P. M. Fives-Taylor, Infect. Immun. 59:2719-2726, 1991). This report characterizes the requirements for invasion of KB cells by A. actinomycetemcomitans. The roles of bacterial and host factors were inv...

Restriction enzyme analysis of PCR-amplified 16S rRNA genes was used to distinguish among clinical isolates of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus which were originally identified by conventional phenotypic methods. This PCR-based method is a reliable and rapid alternative to conventional methods for identification of these bacterial spe...

Clinical Actinobacillus actinomycetemcomitans produces cytolethal distending toxin (CDT) with titers ranging from 10(2) to 10(8) U/mg. Single nucleotide polymorphism analysis of the cdt gene in clinical isolates identified a variation of a single amino acid at residue 281 of CdtB, which significantly affected CDT toxicity by modulating the chromatin-degrading activity of CdtB.

The stability of hemolytic activity, antibiotic resistance and plasmid detection in Actinobacillus actinomycetemcomitans isolates were studied. These characteristics were stable for all experimental conditions. All tested isolates lost or changed some phenotypic characteristics such as colonial morphology and growth in liquid medium.

The species of Capnocytophaga and Aggregatibacter are normal flora and mostly cause periodontal diseases. The soft tissue infection caused by Aggregatibacter often is associated with Actinomyces species. Beside, most Capnocytophaga infections are described in immunocompromised patients. We identified facial cellulitis caused by Capnocytophaga spp and Aggregatibacter (Actinobacillus) actinomycet...

Abundant Secretion of Bioactive Interleukin-1 by Human Macrophages Induced by Actinobacillus actinomycetemcomitans Leukotoxin P. Kelk, R. Claesson, L. Hänström, U. H. Lerner, S. Kalfas, and A. Johansson* Divisions of Periodontology, Oral Microbiology, and Oral Cell Biology, Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden, and School of Dentistry, Aristotle Universit...

Oligonucleotide primers specific for gene clusters involved in the biosynthesis of serotype-specific polysaccharide antigens were designed to identify Actinobacillus actinomycetemcomitans serotypes a to e using the multiplex PCR. This method may be useful for serotype-specific genotyping rapidly and directly from clinical samples containing various organisms.