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Biomedical subjects

A J van Winkelhoff

Publications and source records attributed to A J van Winkelhoff.

At least 73 records · Page 4Linked to original sources
PubMed1993

Seroclassification of hitherto nontypeable Actinobacillus actinomycetemcomitans strains: evidence for a new serotype e.

Serotyping of 89 Actinobacillus actinomycetemcomitans isolates by indirect immunofluorescence with serotype-specific monoclonal antibodies yielded 10 nontypeable strains. The aim of the present study was to re-evaluate the seroclassification of these strains with a different assay. Electroblotted antigens of nontypeable isolates and selected reference strains were immunostained with 37 human sera containing high antibody titers to A. actinomycetemcomitans. Such immunoblots typically showed an immunodominant, serotype-specific antigen smear. Twelve human sera were found to recognize specifically serotype a, 10 serotype b and 9 serotype c. Three sera contained antibodies to 2 or all 3 serotype antigens; 3 sera had no activity to any reference strain smear antigen. There was complete agreement between the seroclassification of the reference strains with the monoclonal and the polyclonal reagents. Seven of the 10 strains, nontypeable with monoclonal antibodies, could also not be typed by the human sera. Of the remaining 3 strains, one belonged to a previously unrecognized serovar of serotype a, and 2 isolates expressed a novel smear antigen detected by the 3 human sera containing no antibodies to the serotype a, b, or c antigens. We propose that these 2 strains be assigned to a new A. actinomycetemcomitans serotype, designated serotype e.

Aggregatibacter actinomycetemcomitans↗
PubMed1993

Porphyromonas endodontalis: prevalence and distribution of restriction enzyme patterns in families.

In this study we determined the prevalence and distribution of Porphyromonas endodontalis in 26 families consisting of 107 subjects. P. endodontalis was present in 24% of the investigated subjects and was recovered most often from the dorsum of the tongue (50%). Isolation was also possible from the tonsils, the buccal mucosa, the saliva and the periodontal pocket. The usefulness of restriction endonuclease analysis as a typing method for this particular species was investigated by typing 19 isolates from unrelated individuals. All these isolates had unique restriction endonuclease patterns. The observed heterogeneity indicates that restriction endonuclease analysis is a sensitive measure of genetic dissimilarity between P. endodontalis isolates and is able to characterize individual isolates. Application of restriction endonuclease analysis to the obtained clinical isolates in this study shows the possibility of the presence of multiple clonal types within one subject. The DNA patterns of all P. endodontalis isolates from unrelated individuals were found to be distinct. In 3 families the DNA patterns of isolates from the mother and her child were indistinguishable. These data indicate the possibility of intrafamilial transmission of P. endodontalis.

Adolescent↗
PubMed1993

K-antigens in Porphyromonas gingivalis are associated with virulence.

We investigated antigens in spreading and non-spreading Porphyromonas gingivalis strains. On the basis of differences in virulence in the mouse model, 8 strains were selected for antiserum production in rabbits. Hyperimmune sera were tested by double immunoprecipitation and immunoelectrophoresis. Besides a common antigen, differences in antigenic composition were observed in the thermolabile antigens between all strains tested. Two different heat-stable antigens were found after heating at 120 degrees C. One such antigen was detected after sonication of the pellet fraction of autoclaved P. gingivalis cells. This antigen cross-reacted with 6 of the 8 immune sera. This somatic antigen was almost neutrally charged and sensitive to sodium periodate treatment, suggestive of lipopolysaccharide. A second heat-stable antigen was detected in the supernatant of autoclaved strains of W83, W50, HG184 and A7A1-28. These non-somatic antigens were strain-specific, i.e., no cross-reactivity was found with heterologous hyperimmune sera. An exception was strain W50, which had a non-somatic heat-stable antigen which was recognized by W83 antiserum. These antigens were resistant to DNAse, RNAse and proteinase-K treatment but were degraded by sodium periodate. In immunoelectrophoresis, these antigens appeared to be negatively charged. These properties are characteristics of a K-antigen, which likely represent a thermostable carbohydrate capsule. The presence of K-antigen correlates very well with the serum resistance, the low chemiluminescence, the resistance to phagocytosis and the need for opsonization with specific antibodies for complement-mediated killing of virulent P. gingivalis strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Survival in transport media of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in human subgingival samples.

The purpose of this study was to evaluate the survival in 3 transport media of 3 suspected periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia. Subgingival samples were taken from 10 patients with severe periodontitis, all harboring at least two of the above-mentioned species. The material was dispersed and aliquots were added to vials containing reduced transport fluid, reduced transport fluid containing 10% Fildes extract, or viability-maintaining microbiostatic medium, anaerobically prepared (VMGA III). Viable counts were determined after 1, 2, 4, 24 and 48 h of storage at 4 degrees C or at room temperature. The results showed that, for up to 4 h of storage, no significant differences existed for all parameters tested. A large increase of the total viable counts was found in VMGA III at room temperature after 24 and 48 h. This was due to an outgrowth of mainly streptococci. Incubation at 4 degrees C yielded often a significantly higher recovery compared to room temperature. After storage at room temperature, the tested bacteria were below detection level in some samples.

Aggregatibacter actinomycetemcomitans↗
PubMed1993

Classification and typing methods of black-pigmented gram-negative anaerobes.

Until recently, black-pigmented Gram-negative anaerobes were classified as 'black-pigmented Bacteroides'. At present, 11 distinct species are recognized in this group. Because of major differences with Bacteroides fragilis, the type species of the genus Bacteroides, new genera have been proposed: Porphyromonas for three asaccharolytic species, and Prevotella for the saccharolytic species. Typing methods have been developed for some species of black-pigmented Gram-negative anaerobes. These include biotyping and serotyping, but relatively few types can be distinguished with these methods. Recently, DNA restriction endonuclease analysis has been used for typing of P. gingivalis, Pr. intermedia and P. endodontalis strains. Great heterogeneity was observed within all three species. This typing method can be useful for epidemiological studies.

Bacterial Typing Techniques↗
PubMed1993

The effect of sibling relationship on the periodontal condition.

The purpose of this investigation was to study clinically as well as microbiologically the effect of sibling relationship on the periodontal condition in a young population with a relatively high prevalence of periodontal disease and deprived from regular dental care. In this study, 23 family units consisting of 3 more siblings were evaluated. In all, 78 subjects aged 15 to 25 years were included in the study. The mean interproximal amount of loss of attachment in this population was 0.29 mm. The individual mean ranged from 0 to 1.27 mm. In 33% of the subjects, > or = 1 sites with a probing depth of 5 mm or more in conjunction with 2 mm of attachment loss were present. The results show a significant sibship effect for: plaque, calculus, loss of attachment, spirochetes on the tongue and in the pocket, Porphyromonas gingivalis on the gingiva and in the saliva and Prevotella intermedia in the saliva. These results support the hypothesis that periodontitis aggregates in families.

Adolescent↗
PubMed1993

In vitro susceptibility of Helicobacter pylori to several antimicrobial combinations.

Synergy between metronidazole and its hydroxymetabolite and between each compound and amoxicillin or tetracycline-HCl was determined against Helicobacter pylori. Metronidazole plus its hydroxymetabolite and either compound combined with amoxicillin showed synergism against all 10 strains of H. pylori tested. Metronidazole plus tetracycline-HCl or the hydroxymetabolite plus tetracycline-HCl acted synergistically against seven and six strains, respectively, acted additively against three strains, and had no additional effect against one strain. These results may help to explain the in vivo efficacies of metronidazole combinations in the treatment of H. pylori-associated gastritis.

Amoxicillin↗
PubMed1993

Antimicrobial therapy in periodontics.

Cause-related therapy in periodontics is aimed at the reduction or elimination of microbial pathogens. Periodontitis is associated with microflorae which may consist of indigenous, exogenous or superinfecting organisms. In general, periodontal infections due to indigenous organisms (endogenous or commensal infections) are treated by continual reduction of the bacterial load, exogenous infections (true infections) by adjunctive antibiotic therapy and superinfections (opportunistic infections) by a combined approach of conventional therapy and improvement of compromising host or environmental factors. Properly selected single drug, combination drug and serial drug therapies show great promise in the treatment of severe periodontitis

Amoxicillin↗
PubMed1992

Porphyromonas (Bacteroides) endodontalis: its role in endodontal infections.

Porphyromonas endodontalis (formerly Bacteroides endodontalis) is a black-pigmented anaerobic Gram-negative rod which is associated with endodontal infections. It has been isolated from infected dental root canals and submucous abscesses of endodontal origin. The presence of P. endodontalis in infected dental root canals has been correlated with symptoms of an acute infection. It is occasionally found on oral mucous membranes and periodontal pockets. P. endodontalis has shown relatively low virulence in experimental monoinfections. In anaerobic mixed infections it can play an essential role. Differences in virulence between strains have been related to capsular material. On the basis of different types of capsules, three serotypes have been described. P. endodontalis is sensitive to a wide range of antibiotics, including the penicillins, the tetracyclines, and metronidazole.

DNA Fingerprinting↗
PubMed1992

In vitro susceptibilities of Actinobacillus actinomycetemcomitans to a number of antimicrobial combinations.

The in vitro susceptibilities of Actinobacillus actinomycetemcomitans to 14 antimicrobial combinations were studied by using the checkerboard titration technique. The results, expressed as the range of the fractional inhibitory concentration indices, were as follows: for metronidazole or its hydroxymetabolite combined with cefixime, 0.2 to 0.6; for moxalactam, 0.2 to 0.6; for penicillin G, 0.3 to 0.6; for tobramycin, 0.8 to 2.0; for erythromycin, 0.8 to 1.7; for ciprofloxacin, 0.2 to 0.6; for tetracycline, 0.8 to 1.2. Our observations indicated that the beta-lactam antibiotics as well as ciprofloxacin act synergistically with both metronidazole and its hydroxymetabolite against A. actinomycetemcomitans. Synergistic interactions were independent of the individual MICs of the antibiotics tested. Erythromycin, tobramycin, and tetracycline combined with either metronidazole or its hydroxymetabolite showed additive to indifferent effects against the five strains of A. actinomycetemcomitans, with the fractional inhibitory concentration indices ranging from 0.8 to 2.0. A. actinomycetemcomitans was found to be highly susceptible to ciprofloxacin (MIC of ciprofloxacin for 90% of strains tested, 0.010 micrograms/ml) and cefixime (MIC of cefixime for 90% of strains tested, 0.8 micrograms/ml). The results indicate that in patients who are allergic to penicillin, cefixime and ciprofloxacin may be useful alternative antibiotics in combination with metronidazole for the treatment of A. actinomycetemcomitans-associated periodontitis.

Actinobacillus Infections↗
PubMed1992

Microbiological and clinical results of metronidazole plus amoxicillin therapy in Actinobacillus actinomycetemcomitans-associated periodontitis.

We report on the microbiological and clinical effects of mechanical debridement in combination with metronidazole plus amoxicillin therapy in 118 patients with Actinobacillus actinomycetemcomitans-associated periodontitis. Patients were categorized into 3 groups: 28 had localized periodontitis; 50 had generalized periodontitis, and 40 had refractory periodontitis. After initial treatment and metronidazole plus amoxicillin therapy 114 of 118 (96.6%) patients had no detectable A. actinomycetemcomitans. Significant reduction in pocket probing depth and gain of clinical attachment were achieved in almost all patients. Four patients were still positive for A. actinomycetemcomitans after therapy. Metronidazole resistance (MIC greater than 25 micrograms/ml) was observed in 2 of 4 strains from these patients. Patients still positive for A. actinomycetemcomitans or Porphyromonas gingivalis showed a significant higher bleeding tendency after therapy. It was concluded that mechanical periodontal treatment in combination with the metronidazole plus amoxicillin therapy is effective for subgingival suppression of A. actinomycetemcomitans in patients with severe periodontitis.

Adult↗
PubMed1992

[Microbiological diagnostics in periodontal treatment].

Periodontal diseases are bacterial infections. The rationale for the use of microbiological diagnostics in periodontal treatment of severe periodontitis patients is discussed as well as the use of adjunct antimicrobial therapy for the elimination of specific bacterial species.

Actinomycetales Infections↗
PubMed1991

[Chronic conjunctivitis caused by oral anaerobic germs].

A patient with chronic, unilateral conjunctivitis is presented. The predominant bacterial flora consisted mainly of Prevotella intermedia (formerly Bacteroides intermedius) and Peptostreptococcus micros. Restriction endonuclease fingerprinting of genomic DNA demonstrated that P. intermedia most probably originated from the oral cavity. In the oral cavity this species was recovered from the dorsum of the tongue, the tonsillar area and the periodontal pockets. Topical treatment with various antibiotics had failed to cure the infection in the past. The condition was cured after systemic therapy with metronidazole and amoxicillin.

Adult↗
PubMed1991

Microbiology in the management of destructive periodontal disease.

This paper summarizes the rationale for the application of microbiology in the management of destructive periodontal diseases. The subgingival microbiota in patients with severe periodontitis is complex and contains high numbers of obligate anaerobic bacteria as well as facultative micro-organisms. It has become clear that major differences exist in the composition of the subgingival microflora. These differences are not only quantitative but also qualitative. Difference in plaque composition is the basis for the application of clinical microbiology in the management of periodontal disease. Several bacterial species have emerged as useful indicators for progressive periodontitis. In this respect, the importance of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius has been shown in a number of studies. It has become clear that A. actinomycetemcomitans is not specifically associated with the local form of juvenile periodontitis, but this micro-organism is probably also of importance in severe periodontitis in adult patients. Selection of individuals with an A. actinomycetemcomitans associated periodontitis is essential since successful treatment in these patients needs an adjunctive antibiotic therapy. Microbiological testing can be useful in patients showing a poor response to periodontal treatment (refractory periodontitis). Factors which may be responsible include poor oral hygiene, poor subgingival debridement, the patient's susceptibility and a subgingival microflora resistant to therapy. In this patient category, microbiological testing is capable of diverting continuing periodontal treatment. Furthermore, microbiology can be useful in evaluating periodontal treatment. Successful elimination of specific periodontopathic microorganisms can be used to determine recall intervals.

Bacteria↗
PubMed1991

Synergistic effects between amoxicillin, metronidazole, and the hydroxymetabolite of metronidazole against Actinobacillus actinomycetemcomitans.

Interactions between metronidazole and amoxicillin, metronidazole and its hydroxymetabolite, and amoxicillin and the hydroxymetabolite of metronidazole were investigated with checkerboard titrations in combination with accurately determined MICs and MBCs. Actinobacillus actinomycetemcomitans was used as the test organism. Synergism was found for all three combinations. Fractional inhibitory concentration indices and fractional bactericidal concentration indices varied from 0.3 to 0.7. These synergistic interactions between these antibiotics may explain the efficacy of the combination of metronidazole and amoxicillin in various bacterial infections, including periodontal disease.

Actinobacillus↗
PubMed1991

Chronic conjunctivitis caused by oral anaerobes and effectively treated with systemic metronidazole plus amoxicillin.

In this study, we report on a case of refractory, unilateral anaerobic conjunctivitis. The predominant anaerobic flora consisted of Prevotella intermedia (formerly Bacteroides intermedius) and Peptostreptococcus micros. By using the technique of restriction endonuclease fingerprinting of genomic DNA, it was shown that the P. intermedia likely originated from the oral cavity. Topically applied antibiotics had failed to suppress the infection in the past. Successful treatment was achieved after systemic administration of metronidazole plus amoxicillin.

Adult↗