Porphyromonas gingivalis: a clonal pathogen?: Diversities in housekeeping genes and the major fimbriae gene

The introduction of multilocus sequence typing (MLST) in infectious disease research has allowed standardized typing of bacterial clones. Through multiple markers around the genome, it is possible to determine the sequence type (ST) of bacterial isolates to establish the population structure of a species. For the periodontal pathogen, Porphyromonas gingivalis, the MLST scheme has been established at www.pubmlst.org/pgingivalis, and data from the database indicate a high degree of genetic diversity and a weakly clonal population structure comparable with Neisseria menigitidis. The major fimbriae (FimA) have been held responsible for the adhesive properties of P. gingivalis and represent an important virulence factor. The fimA genotyping method (PCR based) indicate that fimA genotype II, IV and Ib are associated with diseased sites in periodontitis and tissue specimens from cardiovascular disease. fimA genotyping of the isolates in the MLST database supports the association of genotypes II and IV with periodontitis. As a result of multiple positive PCR reactions in the fimA genotyping, sequencing of the fimA gene revealed only minor nucleotide variation between isolates of the same and different genotypes, suggesting that the method should be redesigned or re-evaluated. Results from several investigations indicate a higher intraindividual heterogeneity of P. gingivalis than found earlier. Detection of multiple STs from one site in several patients with “refractory” periodontitis, showed allelic variation in two housekeeping genes indicating recombination between different clones within the periodontal pocket

Salivary IgA and IgG Antibody Responses against Periodontitis-Associated Bacteria in Crohn’s Disease

Elevated serum immunoglobulin (Ig) antibody levels are observed in Crohn’s disease patients. The aim of this study was to evaluate the salivary IgA and IgG antibody levels against Porphyromonas gingivalis, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, and Prevotella intermedia in Crohn’s disease patients. Eighty-eight participants (47 Crohn’s disease patients and 41 systemically healthy age- and gender-matched controls) were included in the study. Oral and medical health statuses were recorded and salivary samples were collected. Salivary P. gingivalis, T. forsythia, A. actinomycetemcomitans, and P. intermedia carriage were analyzed with DNA sequencing technique, salivary levels of IgG1, IgG2, IgG3, IgG4, and IgM were measured with the Luminex® xMAP™ technique, and salivary IgA and IgG antibody levels against P. gingivalis, T. forsythia, A. actinomycetemcomitans, and P. intermedia were detected by ELISA. As result, higher salivary IgG2 (p = 0.011) and IgG3 (p = 0.006), P. gingivalis IgA (p < 0.001), A. actinomycetemcomitans IgG (p = 0.001), and P. intermedia IgG (p < 0.001) antibody levels were detected in the Crohn’s disease group compared to the controls. Salivary P. gingivalis carriage was lower in the Crohn’s disease group in comparison to the controls (p = 0.024). In conclusion, salivary IgA antibody responses against P. gingivalis and IgG antibody responses against P. intermedia have independent associations with Crohn’s disease

Diversity and anti-fungal susceptibility of Norwegian Candida glabrata clinical isolates

Publisher's version, source: http://dx.doi.org/10.3402/jom.v8.29849.BACKGROUND: Increasing numbers of immunocompromised patients have resulted in greater incidence of invasive fungal infections with high mortality. Candida albicans infections dominate, but during the last decade, Candida glabrata has become the second highest cause of candidemia in the United States and Northern Europe. Reliable and early diagnosis, together with appropriate choice of antifungal treatment, is needed to combat these challenging infections. OBJECTIVES: To confirm the identity of 183 Candida glabrata isolates from different human body sites using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and VITEK®2, and to analyze isolate protein profiles and antifungal susceptibility. The minimum inhibitory concentration (MIC) of seven antifungal drugs was determined for the isolates to elucidate susceptibility. DESIGN: A total of 183 C. glabrata isolates obtained between 2002 and 2012 from Norwegian health-care units were analyzed. For species verification and differentiation, biochemical characterization (VITEK®2) and mass spectrometry (MALDI–TOF) were used. MIC determination for seven antifungal drugs was undertaken using E-tests®. RESULTS: Using VITEK®2, 92.9% of isolates were identified as C. glabrata, while all isolates (100%) were identified as C. glabrata using MALDI-TOF. Variation in protein spectra occurred for all identified C. glabrata isolates. The majority of isolates had low MICs to amphotericin B (≤1 mg/L for 99.5%) and anidulafungin (≤0.06 mg/L for 98.9%). For fluconazole, 18% of isolates had MICs >32 mg/L and 82% had MICs in the range ≥0.016 mg/L to ≤32 mg/L. CONCLUSIONS: Protein profiles and antifungal susceptibility characteristics of the C. glabrata isolates were diverse. Clustering of protein profiles indicated that many azole resistant isolates were closely related. In most cases, isolates had highest susceptibility to amphotericin B and anidulafungin. The results confirmed previous observations of high MICs to fluconazole and flucytosine. MALDI-TOF was more definitive than VITEK®2 for C. glabrata identification

Child saliva microbiota and caries: a randomized controlled maternal education trial in rural Uganda

Throne Holst Foundation and the Centre for Global Health at the University of Oslo’s Research ExceLlence and Innovation in Global HealTh (RELIGHT) programmepublishedVersio

Porphyromonas gingivalis fimbriae

Marginal periodontitis is not a homogeneous disease but is rather influenced by an intricate set of host susceptibility differences as well as diversities in virulence among the harbored organisms. It is likely that clonal heterogeneity of subpopulations with both high and low levels of pathogenicity exists among organisms harbored by individuals with negligible, slight, or even severe periodontal destruction. Therefore, specific virulent clones of periodontal pathogens may cause advanced and/or aggressive periodontitis. Porphyromonas gingivalis is a predominant periodontal pathogen that expresses a number of potential virulence factors involved in the pathogenesis of periodontitis, and accumulated evidence shows that its expression of heterogenic virulence properties is dependent on clonal diversity. Fimbriae are considered to be critical factors that mediate bacterial interactions with and invasion of host tissues, with P. gingivalis shown to express two distinct fimbria-molecules, long and short fimbriae, on the cell surface, both of which seem to be involved in development of periodontitis. Long fimbriae are classified into six types (I to V and Ib) based on the diversity of fimA genes encoding FimA (a subunit of long fimbriae). Studies of clones with type II fimA have revealed their significantly greater adhesive and invasive capabilities as compared to other fimA type clones. Long and short fimbriae induce various cytokine expressions such as IL-1&#x03B1;, IL-&#x03B2;, IL-6, and TNF-&#x03B1;, which result in alveolar bone resorption. Although the clonal diversity of short fimbriae is unclear, distinct short fimbria-molecules have been found in different strains. These fimbriae variations likely influence the development of periodontal disease

The Predictive Role of Tooth Extractions, Oral Infections, and hs-C-Reactive Protein for Mortality in Individuals with and without Diabetes: A Prospective Cohort Study of a 12 1/2-Year Follow-Up

The predictive role of high-sensitivity C-reactive protein (hs-CRP), number of tooth extractions, and oral infections for mortality in people with and without diabetes is unclear. This prospective cohort study is a 12 1/2-year follow-up of the Oslo II study, a health survey in 2000. In all, 12,764 men were invited. Health information was retrieved from 6434 elderly men through questionnaire information, serum measurements, and anthropometric and blood pressure measurements. Diabetes was reported by 425 men. Distinct differences were observed in baseline characteristics in individuals with and without diabetes. In the diabetes group, age and hs-CRP were statistically significant whereas in the nondiabetes group, age, hs-CRP, number of tooth extractions, tooth extractions for infections and oral infections combined, nonfasting glucose, systolic blood pressure, total cholesterol, regular alcohol drinking, daily smoking, and level of education were independent risk factors. The number of tooth extractions <5 was inversely related whereas more extractions increased the risk. Multivariate analyses showed that hs-CRP was a significant predictor in persons with diabetes and tooth extractions and oral infections combined; the number of teeth extracted and hs-CRP were for persons without diabetes. Infection and inflammation were associated with mortality in individuals both with and without diabetes

Multilocus Sequence Typing of Porphyromonas gingivalis Strains from Different Geographic Origins

Porphyromonas gingivalis is an important periodontal pathogen that can be isolated from both active and inactive periodontal lesions. Apparently, differences in virulence between P. gingivalis strains exist, but the mechanisms underlying these differences are not yet fully understood. To obtain more information about pathogenicity and virulence of P. gingivalis, it is relevant to assess the genetic population structure of the species and to examine the occurrence of putative virulence factors against the genetic background. Presently, multilocus sequence typing (MLST) is the best method for analyzing bacterial population structures. Forty P. gingivalis strains from worldwide sources were analyzed by MLST. Internal 310- to 420-bp DNA fragments of the eight ubiquitous chromosomal genes, ftsQ, hagB, gdpxJ, pepO, mcmA, recA, pga, and nah, were amplified by PCR and then sequenced. The number of alleles at individual loci ranged from 2 to 19, and a total of 33 allelic profiles, or sequence types (STs), were identified. Nucleotide variation between alleles was located at one or a few sites. Identical or similar STs were found in isolates from different geographic regions. Our results showed signs of a clonal population structure with a level of recombination not as high as that previously suggested for the species. We also found that P. gingivalis isolates from individual patients were genetically heterogeneous