Enzymatic characterization of some oral and nonoral gram-negative bacteria with the API ZYM system

Complete Genome Sequences of One Salt-Tolerant and Petroleum Hydrocarbon-Emulsifying Terribacillus saccharophilus Strain ZY-1

Salt tolerance is one of the most important problems in the field of environmental governance and restoration. Among the various sources of factors, except temperature, salinity is a key factor that interrupts bacterial growth significantly. In this regard, constant efforts are made for the development of salt-tolerant strains, but few strains with salt tolerance, such as Terribacillus saccharophilus, were found, and there are still few relevant reports about their salt tolerance from complete genomic analysis. Furthermore, with the development of the economy, environmental pollution caused by oil exploitation has attracted much attention, so it is crucial to find the bacteria from T. saccharophilus which could degrade petroleum hydrocarbon even under high-salt conditions. Herein, one T. saccharophilus strain named ZY-1 with salt tolerance was isolated by increasing the salinity on LB medium step by step with reservoir water as the bacterial source. Its complete genome was sequenced, which was the first report of the complete genome for T. saccharophilus species with petroleum hydrocarbon degradation and emulsifying properties. In addition, its genome sequences were compared with the other five strains that are from the same genus level. The results indicated that there really exist some differences among them. In addition, some characteristics were studied. The salt-tolerant strain ZY-1 developed in this study and its emulsification and degradation performance of petroleum hydrocarbons were studied, which is expected to widely broaden the research scope of petroleum hydrocarbon-degrading bacteria in the oil field environment even in the extreme environment. The experiments verified that ZY-1 could significantly grow not only in the salt field but also in the oil field environment. It also demonstrated that the developed salt-tolerant strain can be applied in the petroleum hydrocarbon pollution field for bioremediation. In addition, we expect that the identified variants which occurred specifically in the high-salt strain will enhance the molecular biological understanding and be broadly applied to the biological engineering field.

Metabolomic Status of The Oral Cavity in Chronic Periodontitis

Chronic periodontitis is an inflammatory disease of tooth-supporting tissues associated with Porphyromonas gingivalis. Expansion and invasion of this bacterium into the periodontium is associated with changes in the metabolome of the oral cavity.

MATERIALS AND METHODS

Metabolomics analysis of mouth washout and tongue swab samples based on proton nuclear magnetic resonance (¹H-NMR) method was employed to determine metabolic status of the oral cavity in chronic periodontal disease.

RESULTS

Mouth washout extracts contained a total of 23 metabolites and tongue swab extracts contained 17. Identified metabolites partially overlap with the content of saliva and gingival crevicular fluid. The colonization of the oral cavity of patients with periodontitis by bacteria was manifested in the change in levels of eight metabolites.

CONCLUSION

NMR-based metabolomics analysis is a potentially useful methodological approach for monitoring the pathological processes observed in the oral cavity in the course of periodontitis.

Restriction Fragment Length Polymorphism Analysis of the Fimbrillin Locus, fimA, of Porphyromonas gingivalis

With hybridization probes derived from the fimbrial locus of Porphyromonas gingivalis strain 381, fimA381' restriction fragment length polymorphisms (RFLPs) were examined at the fimbrillin locus in 39 human and animal strains of this species. The 39 strains were subdivided into nine RFLP groups (I-IX) after genomic digests were probed with the internal coding sequence of the fimA381 gene. Thirty-three strains showed one or more AluI fragments of moderate-to-high homology (≥77%) with the internal coding sequence of fimA381. These strains were distributed into the first seven RFLP groups, based solely on the size of the major hybridizing AluI fragment. Five human strains (RFLP Group VIII) had only one Alu I fragment that hybridized very poorly with this probe. One animal strain did not have homology at all (RFLP Group IX). When all AluI fragments that hybridized with fimA381 were analyzed, RFLP groups I-VIII were further differentiated into 25 distinct RFLP patterns. Hybridizations were also performed with the internal coding sequence of fimA381 to probe PstI genomic digests of selected strains that appeared to have lesser homology with fimA381. These hybridizations were performed to determine the level and location of the region of poor homology within the fimA genes of these strains. The results suggested that fimbrial coding sequences are more commonly conserved between these strains in the 5'-region of the fimA locus (≥92% sequence homology). However, the five human strains of RFLP Group VIII had only one PstI fragment that hybridized very poorly with a probe derived from fimA381 coding sequence, and this sequence homology (only > 66%) was located in the central or 3'-end of the fimA gene. The 5'-region of the fimA allele in Group VIII strains did not have any detectable sequence homology. In contrast, the Group VIII strains were highly homologous with the sequences flanking the fimA381 gene. This indicates that these strains do possess a fimA allele at the same chromosomal location as fimA381.

Comparison of Systemic Flurithromycin Therapy and Clinical Procedures in the Treatment of Periodontal Diseases

The purpose of the present investigation was to evaluate, in 20 periodontal patients, the microbial and clinical effects of flurithromycin therapy plus scaling and root planning (SRP) in comparison with SRP alone. Clinical assessments of plaque, bleeding on probing and pocket depth were made prior to SRP alone and SRP plus flurithromycin therapy (375 mg twice daily for 5 days) and after both treatments. Subgingival plaque samples (n. 180) were taken prior to and after both treatments and analyzed by conventional bacteriological procedures. Differences in pocket depth and prevalence of bacterial species were analyzed pre- and post-therapies using statistical analyses. A significant decrease (p<0.001) was seen for pocket depth post SRP alone and post SRP plus flurithromycin. After two treatments, Actinobacillus actinomycetemcomitans, Bacteroides forsythus and Prevotella melaninogenica were eradicated from all tested sites. If we compare the prevalence of the species isolated after SRP alone and after SRP plus flurithromycin statistically significant differences were detected for P. gingivalis and for Fusobacterium nucleatum (p<0.05 and p<0.01, respectively). Flurithromycin can be considered a useful adjunct to mechanical periodontal treatment since it is more efficient in eliminating periodontal pathogens.

Evaluation of three selective media for isolation of Aggregatibacter actinomycetemcomitans

BACKGROUND AND OBJECTIVE

Aggregatibacter actinomycetemcomitans is a pathogen in oral and nonoral infections. Detection and quantification of this pathogen can be performed using selective culture techniques. The aim of this study was to establish the efficacy of two known selective media in their ability to select and support the growth of A. actinomycetemcomitans.

MATERIAL AND METHODS

Trypticase soy bacitracin vancomycin (TSBV) medium and brain-heart infusion agar with vancomycin (Dentaid-1), as well as a modified Dentaid-1 medium (in which the brain-heart infusion agar was substituted with brain-heart infusion broth), were compared. Two-hundred and eighteen clinical samples were used to establish the recovery rate, the number of colony-forming units (CFUs) of A. actinomycetemcomitans as well as the total number of CFUs on the three different types of medium. In addition, the numbers of gram-negative aerobic rods and yeasts were determined.

RESULTS

Both types of Dentaid-1 medium showed a higher recovery of A. actinomycetemcomitans compared with TSBV. However, these differences did not reach statistical significance. The total number of CFUs of A. actinomycetemcomitans recovered was significantly higher on Dentaid-1 compared with TSBV (p = 0.029). The mean number of gram-negative aerobic rods recovered was statistically higher on both types of Dentaid-1 medium in comparison with TSBV. Low numbers of yeasts were recovered occasionally on all test plates.

CONCLUSION

Dentaid-1 is a low-cost effective alternative to TSBV for the isolation and growth of A. actinomycetemcomitans from clinical samples, such as dental plaque, which contain a complex microflora.

Detection and clonal analysis of anaerobic bacteria associated to endodontic-periodontal lesions

BACKGROUND

Microbial agents in root canal systems can induce periodontal inflammation. The aims of this study are to detect anaerobic microorganisms in endodontic-periodontal lesions, determine the genetic diversity among them, and assess the simultaneous colonization of the pulp and periodontal microenvironments by a single clone.

METHODS

Twenty-seven teeth of patients with endodontic-periodontal lesions were selected. Samples were spread on an agar-blood medium, the detection of each species was performed using a polymerase chain reaction, and the determination of the simultaneous presence of the same species in the microenvironments by one or more clones was determined using arbitrarily primed PCR.

RESULTS

Prevotella intermedia (Pi) was the most prevalent species of the colonies in periodontal pockets, whereas Porphyromonas gingivalis (Pg) and Pi were the more prevalent in root canals. Isolates of Pi and Pg were simultaneously identified in root canals and periodontal pockets. Eighteen percent of teeth exhibited the simultaneous colonization by Pg, Tannerella forsythia (previously T. forsythensis), and Porphyromonas endodontalis in the pulp and periodontal microenvironments. The presence of these species was noted even in niches from which no colonies were isolated. Seventeen different genotypes were found in periodontal and pulp sites, with the majority of sites colonized by one or two different genotypes. A high degree of genotype similarity was found for samples of Pg isolated from only one site as well as for those isolated from both microenvironments.

CONCLUSION

Different clones of Pi and Pg with a high intraspecific genotype similarity were found to colonize the same anatomic sites in endodontic-periodontal infections.

Fimbriae-associated genes are biofilm-forming factors in Aggregatibacter actinomycetemcomitans strains

Aggregatibactor actinomycetemcomitans colonizes human periodontal lesions and is implicated in both aggressive periodontitis and chronic periodontitis. Clinical isolated colonies of A. actinomycetemcomitans were rough type. The rough type has a remarkable ability to adhere tenaciously to solid surfaces and colonize firmly. Rough type colonies change into smooth type colonies during the course of repeated inoculation and biofilm-forming activity ceases. Adherence by A. actinomycetemcomitans is mediated by the tight-adherence (tad) gene locus, which includes flp, rcpA and rcpB. In this study, we investigated the relationship between its biofilm-forming ability and expression of the flp, rcpA and rcpB genes associated with fimbriae protein production. First, we changed rough type strain organized biofilm on glass into smooth type and confirmed it by observation of biofilm on glass surfaces. Then, we carried out Real-Time PCR and found that expression of the rcpA and rcpB genes was clearly reduced in smooth type colonies. This suggests that expression of rcpA and rcpB plays a key role in biofilm formation by A. actinomycetemcomitans strains and the establishment of persistent infections in periodontal lesions.

Comparison of periodontal pathogens between cats and their owners

The periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia are strongly associated with periodontal disease and are highly prevalent in humans with periodontitis. Porphyromonas and Tannerella spp. have also been isolated from the oral cavity of cats. The oral microflora in animals was compared with those in humans in earlier studies, but no studies are available on the comparison of the oral microflora from pets and their respective owners. The aim of this study was to determine the presence of these bacteria in the oral microflora of cats and their owners, since animal to human transmission, or vice versa, of oral pathogens could have public health implications. This study investigated the prevalence of Porphyromonas gulae, P. gingivalis, and T. forsythia in the oral microflora of cats and their owners, using culture and polymerase chain reaction (PCR). All Porphyromonas isolates from cats (n=64) were catalase positive, whereas the Porphyromonas isolates from owners (n=7) were catalase negative, suggesting that the isolates from cats were P. gulae whereas those from the owners were P. gingivalis. T. forsythia was recovered from both cats (n=63) and owners (n=31); the proportion of T. forsythia relative to the total CFU was higher in cats with periodontitis than in cats without periodontal disease. Genotyping of T. forsythia isolates (n=54) in six cat/owner couples showed that in one cat/owner couple the T. forsythia isolates (n=6) were identical. These T. forsythia isolates were all catalase positive, which led us to hypothesize that transmission from cats to owners had occurred and that cats may be a reservoir of T. forsythia.

Identification of Lys-Pro-Gln as a novel cleavage site specificity of saliva-associated proteases

The nonsterile environment of the oral cavity facilitates substantial proteolytic processing, not only of resident salivary proteins but also of dietary proteins. To gain insight into whole saliva enzymatic processes, the in vivo generated peptides in this oral fluid were subjected to nano-flow liquid chromatography electrospray ionization tandem mass spectrometry. The 182 peptides identified were predominantly derived from acidic and basic proline-rich proteins, statherin, and histatins. The proteolytic cleavages in the basic proline-rich proteins occurred preferentially after a Gln residue with predominant specificity for the tripeptide Xaa-Pro-Gln, where Xaa in the P(3) position was mostly represented by Lys. Using the synthetic substrates Lys-Pro-Gln-pNA and Gly-Gly-Gln-pNA, the overall K(m) values were determined to be 97 +/- 7.7 and 611 +/- 28 microm, respectively, confirming glutamine endoprotease activity in whole saliva and the influence of the amino acids in positions P(2) and P(3) on protease recognition. The pH optimum of Lys-Pro-Gln-pNA hydrolysis was 7.0, and the activity was most effectively inhibited by antipain and 4-(2-aminoethyl) benzenesulfonyl fluoride, was metal ion-dependent, and not inhibited by cysteine protease inhibitors. A systematic evaluation of enzyme activities in various exocrine and nonexocrine contributors to whole saliva revealed that the glutamine endoprotease is derived from dental plaque and likely microbial in origin. The P(1) site being occupied by a Gln residue is a nonarchetype with respect to known proteases and indicates the presence of novel glutamine-specific endoprotease(s) in oral fluid.

Prevotella copri sp. nov. and Prevotella stercorea sp. nov., isolated from human faeces

Six strains (CB7(T), CB18, CB23, CB26, CB28 and CB35(T)) were isolated from human faeces. Based on phylogenetic analysis, phenotypic characteristics, cellular fatty acid profiles and menaquinone profiles, these strains could be included within the genus Prevotella and made up two clusters. 16S rRNA gene sequence analysis indicated that five strains were most closely related to Prevotella veroralis, sharing about 92 % sequence similarity; the remaining strain was most closely related to Prevotella shahii, sharing about 90 % sequence similarity. All six strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. The cellular fatty acid compositions of the six strains differed significantly from those of other Prevotella species. Five strains (CB7(T), CB18, CB23, CB26 and CB28) contained dimethyl acetals and the major menaquinones of these strains were MK-11, MK-12 and MK-13. The major menaquinones of CB35(T) were MK-12 and MK-13. Based on phenotypic and phylogenetic findings, two novel species, Prevotella copri sp. nov. and Prevotella stercorea sp. nov., are proposed, representing the two different strain clusters. The DNA G+C contents of strains CB7(T) and CB35(T) were 45.3 and 48.2 mol%, respectively. The type strains of P. copri and P. stercorea are CB7(T) (=JCM 13464(T)=DSM 18205(T)) and CB35(T) (=JCM 13469(T)=DSM 18206(T)), respectively.

Phenotypes, serotypes and antibiotic susceptibility of Swedish Porphyromonas gingivalis isolates from periodontitis and periodontal abscesses

This study was conducted to reveal phenotypic, serological subtypes and antibiotic susceptibility among fresh isolates of Porphyromonas gingivalis in a Swedish population with periodontitis and periodontal abscess. Fifty-five subgingival strains were isolated and tentatively designated as P. gingivalis from 55 consecutive paper-point samples taken from 51 patients with periodontitis (at least one site with >6-mm pocket depth) in Sweden and were sent in for microbiological evaluation. Eight P. gingivalis strains from periodontal abscesses were also included. Four P. gingivalis strains served as reference and another four type strains were included. The strains were characterized by colony morphology, biochemical tests, enzyme profile, gas-liquid chromatography and antibiotic susceptibility. The strains were further characterized for whole cell protein profiles using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and were identified to serotype by specific monoclonal antibodies. Among the 55 P. gingivalis strains 35 had smooth (S), 13 rough (R) and seven semi-rough colony morphologies. All strains were phenotypically homogeneous in biochemical tests, enzyme profile and antibiotic susceptibility. All strains produced phenylacetic acid and alpha-fucosidase. Almost all (96%) of the subgingival strains, but relatively fewer (62%) of the abscess strains, belonged to serotype A. Two subgingival and three abscess strains were classified as serotype B. No specific SDS-PAGE protein profiles were recorded for the two serotypes. The P. gingivalis strains from Swedish periodontitis cases showed homogeneity in terms of biochemical phenotypes and antibiotic susceptibility patterns. The strains fell into two serotypes, of which serotype A predominated in the periodontitis cases and serotype B was overrepresented in periodontal abscesses.

A Short-Term Clinical and Microbial Evaluation of Periodontal Therapy Associated With Amalgam Overhang Removal

BACKGROUND

This study evaluated the effect of periodontal therapy plus amalgam overhang removal (PT+AOR) on periodontal status and the presence of Actinobacillus actinomycetemcomitans and Streptococcus mutans and compared two microbiological sampling techniques.

METHODS

Molar teeth with Class II overhang restorations were selected as the test group, and homologous sound teeth were selected as the control group. Periodontal probing depth (PD), clinical attachment level (CAL), and plaque and gingival indices were measured, and restorations were evaluated using radiographs and clinical exploration at baseline (T1) and 90 days after PT+AOR (T2). Microbial samples were taken with dental floss and paper points at T1 and T2. S. mutans and A. actinomycetemcomitans were detected using culture and commercial kits.

RESULTS

Mean values of plaque and gingival indices did not show statistically significant differences between test and control teeth between T1 and T2. At T2, the mean CAL decreased among test teeth, and the number of test teeth positive for A. actinomycetemcomitans showed a decrease, whereas positive samples for S. mutans increased. At T1, an association between the two sampling techniques for both bacteria was found. At T2, dental floss presented low sensitivity values for A. actinomycetemcomitans, whereas paper points showed low sensitivity for S. mutans.

CONCLUSIONS

PT+AOR showed a beneficial effect on clinical parameters and a decrease of A. actinomycetemcomitans. At T1, both sampling techniques showed appropriate results. At T2, the use of paper points was a more sensitive sampling technique for isolate A. actinomycetemcomitans, whereas dental floss was found to be an alternative sampling method for isolate S. mutans.

Reclassification of Bacteroides distasonis, Bacteroides goldsteinii and Bacteroides merdae as Parabacteroides distasonis gen. nov., comb. nov., Parabacteroides goldsteinii comb. nov. and Parabacteroides merdae comb. nov

The characteristics of three Bacteroides species, Bacteroides distasonis, Bacteroides goldsteinii and Bacteroides merdae, were examined. 16S rRNA gene sequence analysis showed that B. distasonis, B. goldsteinii and B. merdae should not be classified as species within the genus Bacteroides. Although B. distasonis, B. goldsteinii and B. merdae were phylogenetically related to Tannerella forsythensis, the ratios of anteiso-C15 : 0 to iso-C15 : 0 in whole-cell methanolysates of the three species were different from that of T. forsythensis. In addition, whereas the major menaquinones of T. forsythensis were MK-10 and MK-11, the major menaquinones of B. distasonis, B. goldsteinii and B. merdae were MK-9 and MK-10. The three species were phenotypically similar to Bacteroides sensu stricto, but phylogenetically distinct. Furthermore, B. distasonis, B. goldsteinii and B. merdae could be differentiated from Bacteroides sensu stricto (predominant menaquinones: MK-10 and MK-11) by the menaquinone composition. This is an important chemotaxonomic characteristic of the three species. On the basis of these data, a novel genus, Parabacteroides gen. nov., is proposed for B. distasonis, B. goldsteinii and B. merdae, with three species, Parabacteroides distasonis gen. nov., comb. nov. (the type species), Parabacteroides goldsteinii comb. nov. and Parabacteroides merdae comb. nov. The type strains of P. distasonis, P. goldsteinii and P. merdae are JCM 5825T (=CCUG 4941T=DSM 20701T=ATCC 8503T), JCM 13446T (=CCUG 48944T) and JCM 9497T (=CCUG 38734T=ATCC 43184T), respectively.

prtHinTannerella forsythensisIs Not Associated With Periodontitis

BACKGROUND

It has been suggested that prtH in Tannerella forsythensis encodes for a cystein proteinase that is associated with its pathogenic potential and can discriminate between periodontal health and disease. The aim of this investigation was to further establish this potentially important observation.

METHODS

A group of 33 consecutive adult patients with periodontitis (mean age: 47.6 +/- 10.1 years) harboring T. forsythensis was selected to investigate the presence of prtH by polymerase chain reaction (PCR). The T. forsythensis strains were isolated by anaerobic culture techniques. To investigate the association of this gene with periodontitis, a group of 14 age-matched subjects (mean age: 56.4 +/- 6.9 years) without any signs of periodontal disease (probing depths <3 mm and no radiographic attachment loss) was tested for comparison. Pure isolates and crude subgingival plaque samples were used as a template for the PCR.

RESULTS

In the group of 33 T. forsythensis-positive patients, we found two T. forsythensis isolates to be prtH negative. Despite repeated analyses, testing of the whole subgingival plaque samples revealed only 17 of 33 samples to be prtH positive. The T. forsythensis isolates from the 14 periodontally healthy subjects were all prtH positive. The odds ratio of the presence of prtH in T. forsythensis in periodontitis patients versus healthy controls is 1.06 (P >0.05).

CONCLUSIONS

On the basis of our data, we conclude that the presence of prtH in T. forsythensis is not discriminative for patients with T. forsythensis-associated periodontitis compared to healthy carriers of T. forsythensis. In addition, the use of whole subgingival plaque samples to test for the prevalence of prtH in bacteria appeared unreliable. Culture of the microorganism is an important condition to receive a sufficient amount of template DNA to detect the specific locus of the genome.

Prevotella multisaccharivorax sp. nov., isolated from human subgingival plaque

Six bacterial strains isolated from the human oral cavity, PPPA16, PPPA20T, PPPA24, PPPA31, EPPA6 and EPPA7, were characterized by determining phenotypic and biochemical features, cellular fatty acid profiles, menaquinone profiles and phylogenetic position based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that the isolates represented the same species of the genus Prevotella. The strains were related to Prevotella dentalis with about 89 % similarity. In addition, the isolates were related to Prevotella sp. oral clone IDR-CEC-0032, which is a representative of the numerically dominant cluster VI in carious dentine lesions [Nadkarni et al. (2004). J Clin Microbiol 42, 5238–5244], with about 99 % similarity. The strains were obligately anaerobic, non-pigmenting, non-spore-forming, non-motile, Gram-negative rods. The isolates could be differentiated from other Prevotella species by d-mannitol, d-melezitose, d-sorbitol and d-trehalose fermentation in API 20A tests. The cellular fatty acid composition of strains PPPA16, PPPA20T, PPPA24, PPPA31, EPPA6 and EPPA7 was significantly different from that of other Prevotella species. Compared with other Prevotella species, only these six strains contained dimethyl acetals. The major menaquinones of the clinical isolates were MK-12 and MK-13, whereas the major menaquinones of other Prevotella species were MK-10 and MK-11. On the basis of these data, a novel Prevotella species, Prevotella multisaccharivorax sp. nov., is proposed, with PPPA20T (=JCM 12954T=DSM 17128T) as the type strain.

Prevalence of oropharyngeal beta-lactamase-producing Capnocytophaga spp. in pediatric oncology patients over a ten-year period

Background

The aim of this study was to evaluate the prevalence of beta-lactamase-producing Capnocytophaga isolates in young children hospitalized in the Pediatric Oncology Department of Hôpital Sud (Rennes, France) over a ten-year period (1993–2002).

Methods

In neutropenic children, a periodic survey of the oral cavity allows a predictive evaluation of the risk of systemic infections by Capnocytophaga spp. In 449 children with cancer, 3,053 samples were collected by oral swabbing and plated on TBBP agar. The susceptibility of Capnocytophaga isolates to five beta-lactams was determined.

Results

A total of 440 strains of Capnocytophaga spp. were isolated, 309 (70%) of which were beta-lactamase producers. The beta-lactamase-producing strains were all resistant to cefazolin, 86% to amoxicillin, and 63% to ceftazidime. The proportion of strains resistant to third-generation cephalosporins remained high throughout the ten-year study, while susceptibility to imipenem and amoxicillin combined with clavulanic acid was always conserved.

Conclusion

These results highlight the risk of antibiotic failure in Capnocytophaga infections and the importance of monitoring immunosuppressed patients and testing for antibiotic susceptibility and beta-lactamase production.

Lipopolysaccharide preparation extracted from Porphyromonas gingivalis lipoprotein-deficient mutant shows a marked decrease in toll-like receptor 2-mediated signaling

We recently demonstrated that a new PG1828-encoded lipoprotein (PG1828LP) was able to be separated from a Porphyromonas gingivalis lipopolysaccharide (LPS) preparation, and we found that it exhibited strong cell activation, similar to that of Escherichia coli LPS, through a Toll-like receptor 2 (TLR2)-dependent pathway. In order to determine the virulence of PG1828LP toward cell activation, we generated a PG1828-deficient mutant of P. gingivalis strain 381 by allelic exchange mutagenesis using an ermF-ermAM antibiotic resistance cassette. A highly purified preparation of LPS from a PG1828-deficient mutant (DeltaPG1828-LPS) showed nearly the same ladder-like patterns in silver-stained gels as a preparation of LPS from a wild-type strain (WT-LPS), as well as Limulus amoebocyte lysate activities that were similar to those of the WT-LPS preparation. However, the ability of the DeltaPG1828-LPS preparation to activate NF-kappaB in TLR2-expressing cells was markedly attenuated. Cytokine production by human gingival fibroblasts was also decreased in response to the DeltaPG1828-LPS preparation in comparison with the WT-LPS preparation, and the activity was comparable to the stimulation of highly purified lipid A of P. gingivalis by TLR4. Further, lethal toxicity was rarely observed following intraperitoneal injection of the PG1828-deficient mutant into mice compared to that with the wild-type strain, while the DeltaPG1828-LPS preparation showed no lethal toxicity. Taken together, these results clearly indicate that PG1828LP plays an essential role in inflammatory responses and may be a major virulence factor of P. gingivalis.

Prevotella multiformis sp. nov., isolated from human subgingival plaque

Four bacterial strains isolated from the human oral cavity, PPPA19, PPPA21T, PPPA28 and PPPA30, were characterized by determining phenotypic and biochemical features, cellular fatty acid profiles and the phylogenetic position based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that each of the isolates was a member of the genus Prevotella. These strains were related to Prevotella denticola with about 95 % similarity. The strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. However, the cells of these strains were often cocci (coccobacilli), depending on the cultivation time. Colonies of different sizes were detected on Eggerth Gagnon agar plates for these strains. The cells forming large colonies were cocci, whereas those forming small colonies were cocci and rods. However, 16S rRNA gene sequence comparison of colonies of different sizes revealed that only a single organism was present. Although these strains had phenotypic characteristics that were similar to those of P. denticola JCM 8528, they could be differentiated from P. denticola JCM 8528 by aesculin hydrolysis and d-cellobiose fermentation in API 20A tests. DNA–DNA hybridization experiments revealed the genomic distinction of these four strains with respect to P. denticola JCM 8528. On the basis of these data, a novel Prevotella species, Prevotella multiformis sp. nov., is proposed, with PPPA21T (=JCM 12541T=DSM 16608T) as the type strain.

Prevotella shahii sp. nov. and Prevotella salivae sp. nov., isolated from the human oral cavity

Two bacterial strains, EHS11T and EPSA11T, which were isolated from the human oral cavity, were characterized in terms of phenotypic and biochemical characteristics, cellular fatty acid profiles and phylogenetic position based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that each of the isolates belonged to a novel species of the genus Prevotella. Strain EHS11T was related to Prevotella loescheii (about 95 % similarity), whereas strain EPSA11T was related to Prevotella oris (about 94 % similarity). Both strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. The cellular fatty acid composition of strain EPSA11T was very similar to that of P. oris JCM 8540T. On the other hand, the cellular fatty acid composition of strain EHS11T was significantly different from those of other Prevotella species. The predominant fatty acids in strain EHS11T are C18 : 1 ω9c, C16 : 0 and C16 : 0 3-OH, whereas other Prevotella species, except for P. loescheii JCM 8530T, possess anteiso-C15 : 0, iso-C17 : 0 3-OH and C18 : 1 ω9c. The predominant fatty acids in P. loescheii JCM 8530T are anteiso-C15 : 0, C16 : 0 and C18 : 1 ω9c. DNA–DNA hybridization experiments revealed a genomic distinction of strains EHS11T and EPSA11T from P. loescheii JCM 8530T and P. oris JCM 8540T. On the basis of these data, two novel Prevotella species are proposed: Prevotella shahii sp. nov. and Prevotella salivae sp. nov. The type strains of P. shahii and P. salivae are EHS11T (=JCM 12083T=DSM 15611T) and EPSA11T (=JCM 12084T=DSM 15606T), respectively.

Genetic analysis of an ambler class A extended-spectrum beta-lactamase from Capnocytophaga ochracea

A beta-lactamase gene (cfxA3, 966 bp) was isolated from a beta-lactam-resistant Capnocytophaga ochracea clinical isolate and amplified using primers from the cfxA gene of Bacteroides vulgatus. The MICs of third-generation cephalosporins were much higher than those of the transconjugant Escherichia coli strain. The deduced protein sequence, by comparison with CfxA2 of Prevotella intermedia, had a Y239D substitution and possessed the characteristics of a class A, group 2e beta-lactamase.

Can toothpaste or a toothbrush with antibacterial tufts prevent toothbrush contamination?

BACKGROUND

Periopathogens and cariogenic species survive more than 48 hours on toothbrushes even under dry storage. This study examined a decontamination of toothbrushes by means of the bactericidal effect of different toothpastes or a special coating of the tufts.

METHODS

Eight untreated periodontitis patients were professionally brushed, using a new toothbrush per quadrant and 3 different toothpastes containing either amine/stannous fluoride (AmF/SnF2), amine fluoride (AmF), or a mild surfactant as major antibacterial component (excipient), or no paste (C). The brushes were rinsed and stored dry at room temperature. At different time intervals, 4 tufts per toothbrush were processed for selective and non-selective culturing procedures. The protocol was repeated comparing AmF/SnF2 and C with 2 toothbrushes with coated tufts (coat1 and coat2).

RESULTS

At baseline, C brushes (n = 16) harbored 10(7), 10(8), and 10(6) colony forming units (CFU) of aerobic, anaerobic, and black pigmented species, respectively. After 24 hours 10(6) CFU of aerobic and anaerobic species could still be cultured from 14 of the 16 brushes. Black-pigmented species remained detectable up to 4 hours; detection frequencies for Fusobacterium nucleatum and Streptococcus mutans at 24 hours were 5/16. With AmF/SnF2 and AmF toothpaste the number of adhering bacteria was already 2 log lower at baseline (P<0.05), but not for the excipient (0.5 log, P = 0.7). With AmF/SnF2 no vital species could be detected after 8 hours. AmF reduced the bacterial survival rate significantly more than the excipient, but less than AmF/SnF2 (P<0.05). The bactericidal effect of coat1 and coat2 was negligible when compared to C (P>0.20), and clearly inferior to the AmF/SnF2 paste (P<0.0001). After 24 hours these brushes still harbored >10(5) CFU.

CONCLUSIONS

Toothpastes can significantly reduce contamination of toothbrushes, but their bactericidal activity is dependent on their composition. Coated tufts failed to limit the bacterial contamination.

A split-mouth study on periodontal and microbial parameters in children with complete unilateral cleft lip and palate

BACKGROUND

Complete unilateral cleft lip and palate (UCLP) is a hereditary or multifactorial malformation that can be corrected successfully with a combined orthodontic, surgical and restorative treatment. Such multidisciplinary treatment takes many years and demands a lot of attention to both patients' teeth and periodontium.

OBJECTIVES

This split-mouth study aimed to compare the periodontal health as well as the microbial parameters between cleft and non-cleft region.

MATERIAL AND METHODS

75 patients (52 males, 23 females) between 8 and 20 years with a complete unilateral cleft lip and palate (before (n = 30), during (n = 34) and after (n = 11) the active orthodontic treatment) volunteered for this study. Four regions were defined for the split-mouth comparison: teeth neighbouring cleft (site 1), tooth in cleft (site 2), and the corresponding contra-lateral teeth, respectively, in the unaffected quadrants (sites 3 and 4). At all sites the following periodontal parameters were recorded: plaque and gingivitis indices, pocket depth, attachment loss, bleeding on probing, tooth mobility (visual and Periotest), radiographic bone loss and gingival width. In addition, three pooled subgingival plaque samples were taken (around tooth in cleft, teeth facing the cleft, and contra-lateral teeth of the latter).

RESULTS

The differences between the teeth neighbouring the cleft and the corresponding contra-lateral opponents were of borderline significance (P <or= 0.05) for the plaque index, the approximal probing depths and the attachment loss (teeth facing the cleft always had slightly higher parameters). When the tooth in the cleft was compared to the contra-lateral tooth, differences were only found for both the approximal probing depths, attachment loss and bone loss, which were significantly higher for the tooth in the cleft. The microbial analysis did not reveal differences between the different sites, neither in the proportion of aerobic and anaerobic bacteria (differences < 0.5 log), nor in the detection frequency of periopathogens.

CONCLUSIONS

These data indicate that the periodontium in UCLP patients can cope well with a long-term orthodontic treatment, even in unfavourable conditions (like absence of attached gingiva and poor oral hygiene).

Effect of triclosan dentifrices on mouth volatile sulphur compounds and dental plaque trypsin-like activity during experimental gingivitis development

BACKGROUND

The objective of this study was to evaluate the effect of three commercial anti-plaque dentifrices containing 0.3% triclosan + 2% pvm/ma (Colgate Total), 0.3% triclosan + 0.75% Zn (Signal Global) and 0.3% triclosan + 5% PPi (Crest Complete) in comparison with an experimental dentifrice (0.3% triclosan + 2% pvm/ma + 0.75% Zn + 4% PPi) and a control dentifrice without anti-plaque agents on trypsin-like activity in dental plaque (detected by the hydrolysis of [Na-Benzoyl-DL-Anginine p-Nitroanilide (BAPNA)] and volatile sulphur compounds (VSCs) in mouth air during experimental gingivitis development.

METHOD

A 5-step double blind, crossover experimental gingivitis study was conducted on 19 volunteers during a 21-day period. The volunteers refrained from brushing an experimental quadrant of teeth. The dentifrices were applied to those teeth via toothshield three times per day; simultaneously they brushed the other teeth with the same dentifrice. After each period, VSCs in mouth air and BAPNA hydrolysis by dental plaque accumulated in the experimental quadrant were determined.

RESULTS

There was an increase (p < 0.05) in VSCs in mouth air when experimental gingivitis was induced in only one quadrant of teeth. None of the dentifrices was able to avoid the increase of VSCs during the experimental gingivitis development. The majority of the antiplaque dentifrices evaluated reduced the increase of VSC formation in comparison with the control (p < 0.05). There was no relationship between the ability of the dentifrices in reducing VSC formation and the inhibition of trypsin-like activity in dental plaque.

CONCLUSIONS

Anti-plaque dentifrices reduce the increase of VSCs that occurs during the development of experimental gingivitis.

Bacterial survival rate on tooth- and interdental brushes in relation to the use of toothpaste

BACKGROUND, AIMS

Previous studies indicated that oral hygiene aids can play a rôle in the intra-oral translocation of pathogens. The survival rate of cariogenic and periodontopathogenic species on toothbrushes, with and without toothpaste, and interdental brushes was presently investigated.

MATERIAL AND METHODS

12 periodontitis patients had their interdental spaces professionally cleaned with interdental brushes and their teeth with new toothbrushes with or without different dentifrices. Each time brushes were rinsed with tap water and stored dry at room temperature. At different time intervals an interdental brush or 4 tufts from a toothbrush were processed for vitality staining and selective and non-selective culturing procedures.

RESULTS

Immediately after rinsing, a toothbrush without toothpaste harboured 10(7), 10(8) and 10(7) colony forming units (CFU) of respectively aerobic, anaerobic and black pigmented species. An insignificant decrease occurred the first 24 hours and after 48 hours still 10(4) CFU of aerobic and anaerobic species could be cultured. No periodontopathogen remained detectable at 8 hours, except for Fusobacterium nucleatum. The proportion of vital bacteria decreased in 48 hours from 50% to 30%. Comparable results were obtained for interdental brushes. The bacterial survival rate on toothbrushes was significantly reduced by the use of a detergent containing toothpaste by 2 log at baseline, another 2 log at 4 hours and an extra log more at 8 hours for aerobic and anaerobic species. A toothpaste without detergent only had an insignificant bactericidal effect.

CONCLUSION

Toothpaste detergents decrease the survival rate of pathogenic species on a toothbrush and can thus limit the risk for bacterial translocation.

Untreated periodontal disease in Indonesian adolescents. Subgingival microbiota in relation to experienced progression of periodontitis

BACKGROUND/AIMS

In an Indonesian population deprived of regular dental care, the experienced progression of disease between baseline (1987) and follow-up (1994) was investigated in relation to the composition of the subgingival microbiota at follow-up. At baseline the age ranged from 15 to 25 years. Clinical and microbiological evaluation was completed in 158 of the 167 subjects available at follow-up.

METHODS

Plaque index (PI), pocket depth (PD), bleeding on probing (BOP), and attachment loss (AL) were scored at the approximal surfaces of all teeth and subgingival calculus on the approximal surfaces of the Ramfjord teeth only (number of sites with subgingival calculus: NSC). A pooled sample of the deepest pocket in each quadrant was evaluated using microbiological culture techniques.

RESULTS

At baseline the mean values of the clinical parameters were AL=0.35 mm, PI=1.01, BOP=0.80 PD=3.25 mm and NSC=6.04 and at follow-up AL=0.75 mm, PI=1.16, BOP=1.19, PD=3.34 mm and NSC=5.85. All parameters except PD and NSC showed a statistically significant increase. At follow-up the prevalence of Actinobacillus actinomycetemcomitans was 40%, of Porphyromonas gingivalis 67%, of Prevotella intermedia 66%, of Fusobacterium nucleatum 79%, of Bacteroides forsythus 16%, of Campylobacter rectus 4%, and of P. micros 6%. No differences in clinical parameters were found between groups with or without these micro-organisms. In 129 subjects AL of > or =2 mm at > or =1 site was found. Logistic regression showed three significant odds-ratio's for experienced progressive periodontitis: Plaque index (12.2), gender (3.4) and Actinobacillus actinomycetemcomitans (2.9).

CONCLUSIONS

The results of this retrospective study suggest that plaque is the most important parameter related to experienced disease progression, and that the presence of A. actinomycetemcomitans may be associated with increased chance of disease progression.

Smoking affects the subgingival microflora in periodontitis

BACKGROUND

Tobacco smoking has been identified as one major risk factor for destructive periodontal disease. Scaling and root planing have been shown to be less effective in smokers with periodontitis. The aim of the present study was to compare the subgingival microbial flora of treated and untreated smokers and non-smokers.

METHODS

Four independent adult patient groups with periodontitis were included in this investigation: 88 untreated smokers (U-S); 90 untreated non-smokers (U-NS); 119 treated non-smokers (T-NS); and 171 treated smokers (T-S). Clinical variables included cumulative plaque index (CPI), probing depth (PD), clinical attachment level (CAL), cumulative bleeding index (CBI), and cumulative suppuration index (CSI). Paper point samples from the deepest bleeding pocket in each quadrant of the dentition were analyzed for the presence and levels of 6 periodontal bacterial pathogens using anaerobic culture techniques.

RESULTS

U-S showed a higher mean cumulative plaque index than U-NS (3.5 versus 2.7). Mean PD and mean CAL were higher in the T-S in comparison to the T-NS group (7.0 versus 6.6 mm and 5.6 versus 4.7 mm, respectively). Microbiological characteristics of U-S were a higher prevalence of Prevotella intermedia/nigrescens and higher mean levels of Peptostreptococcus micros (Pm) and Fusobacterium nucleatum (Fn). T-S patients were characterized by higher prevalence of Bacteroides forsythus (Bf), Pm, and Campylobacter rectus (Cr) and higher mean levels of Pm and Fn. The mean percentage of B. forsythus tended to be higher in the T-S group than in the T-NS group (6.9% versus 5.6%). The relative risk to be infected with Bf, Pm, and Cr was statistically higher in smokers (odds ratios: 1.9, 1.9, and 1.6, respectively). The chance to find > or =10% of Bf, Pm, and/or Fn was 3.3 higher in smokers when A. actinomycetemcomitans and P gingivalis were absent. Detection of > or =20% Pm/Fn in treated patients was strongly associated with smoking (odds ratio 13.8, P= 0.002).

CONCLUSIONS

Smoking is a determining factor for the composition of the subgingival microflora in adult patients with periodontitis and may select for a specific cluster of periodontal pathogens, notably Bf, Pm, Fn, and Cr. On the basis of these observations, smoking, among other criteria, may be one parameter to use in deciding to treat refractory periodontitis in smokers with a systemic antibiotic therapy directed against smoking-associated periodontal bacteria.

A 2-step non-surgical procedure and systemic antibiotics in the treatment of rapidly progressive periodontitis

BACKGROUND

In the last few years knowledge about periodontal infections has increased enormously, nevertheless practitioners are still seeking guidelines for suitable treatment concepts.

METHODS

The aim of this study was to examine the effect of doxycycline, metronidazole, and clindamycin used adjunctively in a 2-step nonsurgical procedure in patients with rapidly progressive periodontitis (RPP). The first step included scaling, root planing, and polishing (SRP) in each quadrant using 4 to 5 visits. The second step included full-mouth enhanced root planing (RP) and wound dressing in 1 or 2 visits after SRP and the beginning of antibiotic therapy. Forty-eight patients (mean age 32.4 years) with generalized RPP, with an average of 16 sites with probing depths (PD) deeper than 8 mm, and high counts of Porphyromonas gingivalis were randomly assigned to 4 different groups: group 1 (doxycycline) n = 12, group 2 (metronidazole) n = 15, group 3 (clindamycin) n = 11, and group 4 (control group; no antibiotic treatment) n = 10. Clinical evaluations, including plaque index (PI), sulcus bleeding index (SBI), probing depth (PD), clinical attachment level (CAL), and bacteriological and crevicular cell sampling, were done at baseline (BL), 3 weeks after SRP, and 6 and 24 months after RP.

RESULTS

After the first step (SRP), we observed an improvement of PI and SBI in all 4 groups, but did not see any statistically significant PD reduction 3 weeks after SRP compared to baseline. However, 6 and 24 months after the second step (RP) we observed a significantly greater reduction of PD in groups 2 and 3 and a significantly greater CAL gain in comparison to groups 1 and 4. After 24 months, the attachment level gain in group 1 and group 4 was less than 1.5 mm, and less than 1.0 mm in PD site categories 6 to 9 mm and >9 mm. PI showed no significant difference between the groups throughout the period after SRP until 24 months, compared to 3 weeks after SRP. SBI decreased most in the metronidazole and clindamycin groups. P. gingivalis and Actinobacillus actinomycetemcomitans were almost completely eradicated in these 2 groups 24 months after RP. In addition, the phagocytotic capacity of crevicular polymorphonuclear neutrophils was increased in groups 2 and 3 after the second step.

CONCLUSIONS

The present results show that metronidazole and clindamycin are effective antibiotics when used adjunctively in a 2-step nonsurgical procedure of scaling and root planing in RPP patients.

Altered chemotactic behavior of crevicular PMNs in different forms of periodontitis

BACKGROUND, AIMS

Polymorphonuclear neutrophils (PMN) are the predominant host defence cells in the gingival sulcus. Previous work demonstrates that the in vitro phagocytosis of crevicular cells in localised early onset periodontitis (LEOP) and generalised early onset periodontitis (GEOP) lesions is diminished. The present study extends this work by characterizing the chemotaxis function of crevicular fluid (CF) PMNs in various forms of periodontitis.

METHODS

We investigated 7 patients with LEOP, 11 patients with GEOP, 12 patients with adult periodontitis (AP) and 2 age- and sex-matched healthy control groups. The two deepest sites of each quadrant in test and control subjects were selected for crevicular sampling. Chemotaxis was performed in a micro chamber (moist atmosphere, 5% CO2, 37 degrees C, 30 min) using N-formyl-methionyl-leucyl-phenylalanine (FMLP, 1 x 10(-7) mol FMLP/l) as a chemoattractant. The total chemotaxis was defined as the difference between the number of cells migrating towards FMLP minus the number of cells migrating towards PBS, counted in 20 randomly selected fields. Membranes were examined microscopically at 400 x magnification.

RESULTS

The chemotactic activity in the adult periodontitis group was significantly higher compared to the age-related control group. However, we found a statistically significant reduction of chemotactic activity in LEOP and GEOP patients compared to the controls.

CONCLUSIONS

These results indicate an increase of chemotactic activity from CF-PMN in patients with adult periodontitis, but on the other hand, a significant reduction of chemotactic responsiveness of these cells in LEOP and GEOP lesions.

In vitro susceptibilities of Capnocytophaga isolates to beta-lactam antibiotics and beta-lactamase inhibitors

The susceptibilities of 43 pharyngeal isolates of Capnocytophaga to beta-lactam antibiotics, alone or in combination with beta-lactamase inhibitors, were tested by an agar dilution method. The 34 beta-lactamase-positive strains were highly resistant to beta-lactams, but the intrinsic activities of clavulanate, tazobactam, and sulbactam against Capnocytophaga, even beta-lactamase producers, indicates that these beta-lactamase inhibitors could be used for empirical treatment of neutropenic patients with oral sources of infection.

Isolation, cloning, and expression of an acid phosphatase containing phosphotyrosyl phosphatase activity from Prevotella intermedia

A novel acid phosphatase containing phosphotyrosyl phosphatase (PTPase) activity, designated PiACP, from Prevotella intermedia ATCC 25611, an anaerobe implicated in progressive periodontal disease, has been purified and characterized. PiACP, a monomer with an apparent molecular mass of 30 kDa, did not require divalent metal cations for activity and was sensitive to orthovanadate but highly resistant to okadaic acid. The enzyme exhibited substantial activity against tyrosine phosphate-containing peptides derived from the epidermal growth factor receptor. On the basis of N-terminal and internal amino acid sequences of purified PiACP, the gene coding for PiACP was isolated and sequenced. The PiACP gene consisted of 792 bp and coded for a basic protein with an M(r) of 29,164. The deduced amino acid sequence exhibited striking similarity (25 to 64%) to those of members of class A bacterial acid phosphatases, including PhoC of Morganella morganii, and involved a conserved phosphatase sequence motif that is shared among several lipid phosphatases and the mammalian glucose-6-phosphatases. The highly conservative motif HCXAGXXR in the active domain of PTPase was not found in PiACP. Mutagenesis of recombinant PiACP showed that His-170 and His-209 were essential for activity. Thus, the class A bacterial acid phosphatases including PiACP may function as atypical PTPases, the biological functions of which remain to be determined.

One stage full- versus partial-mouth disinfection in the treatment of chronic adult or generalized early-onset periodontitis. II. Long-term impact on microbial load

BACKGROUND

Recent studies showed the clinical benefits of a one stage full-mouth disinfection, when compared to the worldwide standard treatment strategy of consecutive root planings per quadrant without proper disinfection of the remaining intraoral niches. The purpose of this study was to investigate the microbiological benefits of such a one stage full-mouth disinfection with special attention to all intraoral niches for periodontopathogens and to evaluate the perception by the patients of the new treatment strategy.

METHODS

Sixteen patients with early-onset periodontitis and 24 patients with severe adult periodontitis were randomly assigned to test and control groups. The control group was scaled and root planed, per quadrant, at 2-week intervals and given oral hygiene instructions. The test group received the one stage full-mouth disinfection treatment. At baseline and after 1, 2, 4, and 8 months, microbiological samples were taken from all niches (tongue, mucosa, saliva, and pooled samples from single- and multi-rooted teeth). The samples were cultured on selective and non-selective media. Patient perception of the treatment was evaluated using a questionnaire.

RESULTS

In comparison to the standard therapy, the one stage full-mouth disinfection resulted in significant additional microbial improvements. The test group showed larger reductions in the proportions of spirochetes and motile organisms in the subgingival flora, and more significant reductions in the density of key pathogens, with even the eradication of P. gingivalis. The beneficial effects in the other niches were primarily restricted to the number of colony-forming units/ml of black-pigmented bacteria, especially on the mucosa and in the saliva and to a lesser extent on the tongue. Both treatments were well tolerated by the patients and the overall severity rating for both therapies was comparable, although 4 quadrants were treated within 24 hours in the test group versus only 1 in the control group. The full-mouth disinfection approach resulted more frequently in a slight increase of body temperature, especially after the second day.

CONCLUSIONS

These findings support the benefit of a one stage full-mouth disinfection in the treatment of patients with either chronic adult or early-onset periodontitis.

Microbiological understandings and mysteries of noma (cancrum oris)

The microbiologic history of noma was reviewed. Studies have associated the disease process with large numbers of fusiform bacilli and spirochetal organisms. In order to study the microbiology of the staging and infection periods of noma 62 Nigerian children, aged 3-14 years, 22 children had acute necrotizing ulcerative gingivitis (ANUG) and were also malnourished, 20 exhibited no acute necrotizing ulcerative gingivitis but were malnourished and 20 were free of acute necrotizing ulcerative gingivitis and in good nutritional state) were evaluated for the presence of viruses and oral microorganisms. The ANUG cases in the malnourished children had a higher incidence of Herpesviridae, the main virus being detected was cytomegalovirus. There were more anaerobic microorganisms recovered, with Prevotella intermedia as the predominant isolate, in the malnourished children as compared to the healthy children. A study of the predominant microflora in active sites of noma lesions was carried out in eight noma patients, 3-15 years of age, in Sokoto State, northwestern Nigeria. Fusobacterium necrophorum was recovered from 87.5% of the noma lesions. Oral microorganisms isolated included Prevotella intermedia, alpha-hemolytic streptococci and Actinomyces spp. which were isolated from 75.0, 50.0 and 37.5% of the patients, respectively. Peptostreptococcus micros, Veillonella parvula, Staphylococcus aureus and Pseudomonas spp. were each recovered from one lesion. All strains were observed to be sensitive to all of the antibiotics tested with the exception of one strain of P. intermedia which showed resistance to penicillin. The pathogenic mechanisms of F. necrophorum as a trigger organism were discussed. The isolation from human noma lesions of F. necrophorum, a pathogen primarily associated with animal diseases, may have important etiologic and animal transmission implications.

Evaluation of two commercial kits and arbitrarily primed PCR for identification and differentiation of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus

The closely related species Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus are common findings in oral microbiota. The aims of this study were to evaluate the applicability of the Rapid NH and API ZYM kits and arbitrarily primed PCR (AP-PCR) in the identification and differentiation of the three species from each other. The material included 62 clinical isolates and three reference strains of A. actinomycetemcomitans representing the 5 serotypes and 18 AP-PCR genotypes. Haemophilus species included 12 clinical isolates and 11 reference strains of H. aphrophilus, H. paraphrophilus, and 5 other species. For the PCR amplification, the oligonucleotide 5'-CAGCACCCAC-3' was used as a primer. Contrary to the consistent performance of API ZYM, the Rapid NH system was able to identify only 10 of 65 (15%) A. actinomycetemcomitans isolates, whereas all Haemophilus species were correctly identified. The API ZYM test differentiated A. actinomycetemcomitans from H. aphrophilus and H. paraphrophilus by negative beta-galactosidase and alpha-glucosidase reactions and a positive esterase lipase reaction. However, the API ZYM test was unable to differentiate H. aphrophilus from H. paraphrophilus, it also could not differentiate A. actinomycetemcomitans serotypes from each other. Among the H. aphrophilus isolates three AP-PCR genotypes and among H. paraphrophilus isolates only one AP-PCR genotype, distinct from those of A. actinomycetemcomitans, were found. The Rapid NH test showed poor ability to identify clinical isolates of all A. actinomycetemcomitans serotypes. Moreover, AP-PCR genotyping proved to be a rapid method for the species differentiation of A. actinomycetemcomitans, H. aphrophilus, and H. paraphrophilus.

Life below the gum line: pathogenic mechanisms of Porphyromonas gingivalis

Porphyromonas gingivalis, a gram-negative anaerobe, is a major etiological agent in the initiation and progression of severe forms of periodontal disease. An opportunistic pathogen, P. gingivalis can also exist in commensal harmony with the host, with disease episodes ensuing from a shift in the ecological balance within the complex periodontal microenvironment. Colonization of the subgingival region is facilitated by the ability to adhere to available substrates such as adsorbed salivary molecules, matrix proteins, epithelial cells, and bacteria that are already established as a biofilm on tooth and epithelial surfaces. Binding to all of these substrates may be mediated by various regions of P. gingivalis fimbrillin, the structural subunit of the major fimbriae. P. gingivalis is an asaccharolytic organism, with a requirement for hemin (as a source of iron) and peptides for growth. At least three hemagglutinins and five proteinases are produced to satisfy these requirements. The hemagglutinin and proteinase genes contain extensive regions of highly conserved sequences, with posttranslational processing of proteinase gene products contributing to the formation of multimeric surface protein-adhesin complexes. Many of the virulence properties of P. gingivalis appear to be consequent to its adaptations to obtain hemin and peptides. Thus, hemagglutinins participate in adherence interactions with host cells, while proteinases contribute to inactivation of the effector molecules of the immune response and to tissue destruction. In addition to direct assault on the periodontal tissues, P. gingivalis can modulate eucaryotic cell signal transduction pathways, directing its uptake by gingival epithelial cells. Within this privileged site, P. gingivalis can replicate and impinge upon components of the innate host defense. Although a variety of surface molecules stimulate production of cytokines and other participants in the immune response, P. gingivalis may also undertake a stealth role whereby pivotal immune mediators are selectively inactivated. In keeping with its strict metabolic requirements, regulation of gene expression in P. gingivalis can be controlled at the transcriptional level. Finally, although periodontal disease is localized to the tissues surrounding the tooth, evidence is accumulating that infection with P. gingivalis may predispose to more serious systemic conditions such as cardiovascular disease and to delivery of preterm infants.

Proteases of Porphyromonas gingivalis: what don't they do?

The gram-negative anaerobic bacterium Porphyromonas gingivalis has been strongly associated with the causation of human periodontal diseases. One distinguishing property of these organisms that has been implicated in periodontal destruction is the expression of potent protease activity. Recent biochemical and genetic approaches have clearly demonstrated that at least five distinct proteases are elaborated by these organisms. The utilization of monospecific mutants defective in individual proteases has demonstrated that protease activity is important in virulence but also has suggested the complexity of the functions of the enzymes in the physiology of these microorganisms. This review summarizes current progress in assessing the role of these enzymes in periodontal inflammation and discusses some unresolved issues relevant to the significance of P. gingivalis proteases in virulence.

Purification and characterization of alkaline phosphatase containing phosphotyrosyl phosphatase activity from the bacterium Prevotella intermedia

A novel alkaline phosphatase, designated PiALP, has been purified and characterized from Prevotella intermedia ATCC 25611, an anaerobe implicated in progressive periodontal disease. The enzyme was a homodimer of apparently identical subunits of Mr 54 kDa. Thiol-reducing agents completely inhibited the purified enzyme. The enzyme was highly stable even at 80 degrees C. It exhibited substantial activity against tyrosine-phosphate-containing Raytide. The phosphatase activity was sensitive to orthovanadate and Zn2+ but highly resistant to okadaic acid. The amino acid sequence of peptides derived from PiALP showed a high degree of identity (65%) with alkaline phosphatases from Zymomonas mobilis and Synechococcus. The present results imply that PiALP might represent a new family of alkaline phosphotyrosyl phosphatases which has not been described previously.

The effect of a one-stage full-mouth disinfection on different intra-oral niches. Clinical and microbiological observations

A treatment for periodontal infections often consists of consecutive rootplanings (per quadrant, at a 1- to 2-week interval), without a proper disinfection of the remaining intra-oral niches (untreated pockets, tongue, saliva, mucosa and tonsils). Such an approach, could theoretically lead to a reinfection of previously-treated pockets. The present study aims to examine the effect of a full-mouth disinfection on the microbiota in the above-mentioned niches. Moreover, the clinical benefit of such an approach was investigated. 16 patients with severe periodontitis were randomly allocated to a test and a control group. The patients from the control group were scaled and rootplaned, per quadrant, at 2-week intervals and obtained oral hygiene instructions. The patients from the test group received a full-mouth disinfection consisting of: scaling and rootplaning of all pockets in 2 visits within 24 h, in combination with tongue brushing with 1% chlorhexidine gel for 1 min, mouth rinsing with a 0.2% chlorhexidine solution for 2 min and subgingival irrigation of all pockets (3x in 10 min) with 1% chlorhexidine gel. Besides oral hygiene, the test group rinsed 2x daily with 0.2% chlorhexidine and sprayed the tonsils with a 0.2% chlorhexidine for 2 months. Plaque samples (pockets, tongue, mucosa and saliva) were taken at baseline and after 2 and 4 months, and changes in probing depth, attachment level and bleeding on probing were reported. The full-mouth disinfection resulted in a statistically significant additional reduction/elimination of periodontopathogens, especially in the subgingival pockets, but also in the other niches. These microbiological improvements were reflected in a statistically-significant higher probing depth reduction and attachment gain in the test patients. These findings suggest that a disinfection of all intra-oral niches within a short time span leads to significant clinical and microbiological improvements for up to 4 months.