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- Porphyromonas gingivalis: Major Periodontopathic Pathogen Overview. [REVIEW]
- J Immunol Res 2014.:476068.
Porphyromonas gingivalis is a Gram-negative oral anaerobe that is involved in the pathogenesis of periodontitis and is a member of more than 500 bacterial species that live in the oral cavity. This anaerobic bacterium is a natural member of the oral microbiome, yet it can become highly destructive (termed pathobiont) and proliferate to high cell numbers in periodontal lesions: this is attributed to its arsenal of specialized virulence factors. The purpose of this review is to provide an overview of one of the main periodontal pathogens-Porphyromonas gingivalis. This bacterium, along with Treponema denticola and Tannerella forsythia, constitute the "red complex," a prototype polybacterial pathogenic consortium in periodontitis. This review outlines Porphyromonas gingivalis structure, its metabolism, its ability to colonize the epithelial cells, and its influence upon the host immunity.
- Genetic characteristics and pathogenic mechanisms of periodontal pathogens. [Journal Article]
- Adv Dent Res 2014 May; 26(1):15-22.
Periodontal disease is caused by a group of bacteria that utilize a variety of strategies and molecular mechanisms to evade or overcome host defenses. Recent research has uncovered new evidence illuminating interesting aspects of the virulence of these bacteria and their genomic variability. This paper summarizes some of the strategies utilized by the major species - Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, and Porphyromonas gingivalis - implicated in the pathogenesis of periodontal disease. Whole-genome sequencing of 14 diverse A. actinomycetemcomitans strains has revealed variations in their genetic content (ranging between 0.4% and 19.5%) and organization. Strikingly, isolates from human periodontal sites showed no genomic changes during persistent colonization. T. forsythia manipulates the cytokine responses of macrophages and monocytes through its surface glycosylation. Studies have revealed that bacterial surface-expressed O-linked glycans modulate T-cell responses during periodontal inflammation. Periodontal pathogens belonging to the "red complex" consortium express neuraminidases, which enables them to scavenge sialic acid from host glycoconjugates. Analysis of recent data has demonstrated that the cleaved sialic acid acts as an important nutrient for bacterial growth and a molecule for the decoration of bacteria surfaces to help evade the host immune attack. In addition, bacterial entry into host cells is also an important prerequisite for the lifestyle of periodontal pathogens such as P. gingivalis. Studies have shown that, after its entry into the cell, this bacterium uses multiple sorting pathways destined for autophagy, lysosomes, or recycling pathways. In addition, P. gingivalis releases outer membrane vesicles which enter cells via endocytosis and cause cellular functional impairment.
- Gut microbiome of the Hadza hunter-gatherers. [Journal Article]
- Nat Commun 2014.:3654.
Human gut microbiota directly influences health and provides an extra means of adaptive potential to different lifestyles. To explore variation in gut microbiota and to understand how these bacteria may have co-evolved with humans, here we investigate the phylogenetic diversity and metabolite production of the gut microbiota from a community of human hunter-gatherers, the Hadza of Tanzania. We show that the Hadza have higher levels of microbial richness and biodiversity than Italian urban controls. Further comparisons with two rural farming African groups illustrate other features unique to Hadza that can be linked to a foraging lifestyle. These include absence of Bifidobacterium and differences in microbial composition between the sexes that probably reflect sexual division of labour. Furthermore, enrichment in Prevotella, Treponema and unclassified Bacteroidetes, as well as a peculiar arrangement of Clostridiales taxa, may enhance the Hadza's ability to digest and extract valuable nutrition from fibrous plant foods.
- Epidemiology of yaws: an update. [REVIEW]
- Clin Epidemiol 2014.:119-128.
Yaws, a neglected tropical disease, is targeted for eradication by 2020 through large-scale mass-treatment programs of endemic communities. A key determinant for the success of the eradication campaign is good understanding of the disease epidemiology. We did a review of historical trends and new information from endemic countries, with the aim of assessing the state of knowledge on yaws disease burden. Transmission of yaws is now present in Africa, Asia, and the South Pacific. At least 12 countries are known to harbor yaws cases and 21 to 42 million people live in endemic areas. Between 2008 and 2012 more than 300,000 new cases were reported to the World Health Organization. Yaws presented high geographical variation within a country or region, high seasonality for incidence of active disease, and evidence that low standards of hygiene predispose to suffering of the disease. Key data issues include low levels of reporting, potential misdiagnosis, and scarce documentation on prevalence of asymptomatic infections. Currently available data most likely underestimates the magnitude of the disease burden. More effort is needed in order to refine accuracy of data currently being reported. A better characterization of the epidemiology of yaws globally is likely to positively impact on planning and implementation of yaws eradication.
- Identification of Treponema pedis as the predominant Treponema species in porcine skin ulcers by fluorescence in situ hybridization and high-throughput sequencing. [JOURNAL ARTICLE]
- Vet Microbiol 2014 Mar 25.
Skin lesions often seen in pig production are of great animal welfare concern. To study the potential role of Treponema bacteria in porcine skin ulcers, we investigated the presence and distribution of these organisms in decubital shoulder ulcers (n=51) and ear necroses (n=54) by fluorescence in situ hybridization (FISH) and high-throughput sequencing. In addition, two cases of facial ulcers and five cases of other skin ulcers were included in the study. Samples from all 112 skin lesions and intact skin from pigs without skin ulcers (n=14) were screened by FISH. Three different oligonucleotide probes targeting 16S rRNA were used, specific for domain bacterium, Treponema spp. and species T. pedis. Screening showed that two cases each of facial and other ulcers, 35 (69%) of shoulder ulcers and 32 (59%) of ear necroses were positive for Treponema spp. T. pedis was the unequivocally, predominant species typically constituting more than 90% of the treponemes in a lesion, assessed visually by microscopy. Altogether, T. pedis was demonstrated in 69 of the 71 Treponema spp. positive lesions. We conclude that Treponema spp. are frequently present and abundant in various skin ulcers of pigs. The results from this study point toward an important role of T. pedis as a secondary bacterial infection in porcine skin ulcers, especially in severe and chronic lesions.
- [The many faces of neurosyphilis]. [English Abstract, Journal Article]
- Duodecim 2014; 130(6):589-93.
Syphilis is an infectious disease caused by Treponema pallidum. We describe two patients with chronic syphilis causing neurosyphilis. The first had had several brain infarctions due to the presence of meningovascular syphilis. Second patient suffered from motor and psychiatric symptoms caused by syphilis. The symptoms of our patients were alleviated by antibiotic therapy. Recognition of the multifaceted symptom picture of syphilis is increasingly important, because the occurrence of the disease has increased in our country over the last few decades. An early enough treatment can prevent permanent disability of the patient.
- Assessment of periodontal and opportunistic flora in patients with peri-implantitis. [JOURNAL ARTICLE]
- Clin Oral Implants Res 2014 Apr 10.
To assess the presence of periodontal and opportunistic organisms in patients with peri-implantitis.Thirty-three partially edentulous subjects (22 women, 11 men), aged 32-90 years, who had one or more implants with peri-implantitis were included. Peri-implantitis was defined as: (i) the presence of bleeding on probing and/or suppuration and (ii) radiographic images showed marginal bone loss >1.8 mm after 1 year in function. Criteria for inclusion were: (i) partially edentulous patients having at least one implant diagnosed with peri-implantitis; (ii) no antibiotic therapy for 6 months prior to clinical examination. Following this definition, a total of 48 implants were diagnosed with peri-implantitis. Subgingival bacterial samples were obtained with sterile paper points from infected implants and selected teeth of each individual. Periodontopathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia and Treponema denticola) were detected by multiplex PCR targeting 16S rDNA. Samples were placed in reduced transport medium and cultured for opportunistic pathogens (Staphylococcus aureus, enteric bacteria, Pseudomonas and yeasts).Twenty-two patients yielded positive results for P. gingivalis, 25 for T. forsythia, eight for P. intermedia and 13 for T. denticola. None of the patients yielded a positive result for A. actinomycetemcomitans. Non-periodontal species were found in five patients (15% of total). P. aeruginosa was found in four (12%) patients, and C. albicans (3%) and S. aureus in one patient (3%) each. In two cases of peri-implantitis, none of the periodontal or opportunistic microorganisms studied were detected in either implant or tooth samples. When results of the periodontopathic bacteria from the implant and tooth samples of the same patient were compared, 18 patients (54%) showed the same results for both samples and 15 (45%) patients different results.The implant surface may be colonized with pathogens different from periodontal bacteria. Opportunistic pathogens such as P. aeruginosa, S. aureus and C. albicans may be associated with implant failure.
- Prevalence of antibodies against Treponema pallidum among HIV-positive patients in a tertiary care hospital in Mexico. [JOURNAL ARTICLE]
- Int J STD AIDS 2014 Apr 8.
Our objective was to determine the seroprevalence of syphilis among HIV-infected patients in a tertiary care hospital in Mexico City. A cross-sectional study was developed, and 318 HIV-positive patients were evaluated from January to February 2013 at Hospital de Infectología, National Medical Center 'La Raza' (a tertiary care hospital specialising in infectious diseases in Mexico City). Laboratory data were screened for the detection of antibodies against Treponema pallidum. Patients completed a questionnaire relating to socio-demographic data and factors associated with syphilis. Of the 318 patients, 83% were men. The mean age ± SD was 36 ± 11 years; 52% were men who have sex with men and 47% had undertaken higher education. The overall seroprevalence of syphilis among these patients was 25% (95% confidence interval 21%, 30%). Men who have sex with men had a significantly higher seroprevalence (30% vs. 15%, p = 0.009). We conclude that, in Mexico, there is a high seroprevalence of syphilis in HIV-infected patients and that men who have sex with men are the group most affected.
- IUGR and infections. [REVIEW]
- Early Hum Dev 2014 Mar.:S42-S44.
Intra-uterine growth retardation (IUGR) is usually defined as impaired growth and development of the fetus and/or its organs during gestation. Infants are defined small for gestational age (SGA), following IUGR, when the birth weight is below the 10th percentile. Pre-natal congenital infections caused by T. gondii, rubella, cytomegalovirus (CMV), herpes simplex virus (HSV), varicella-zoster virus (VZV), and Treponema are associated with, and account for, approximately 5 to 15% of IUGR. On the other hand, SGA preterm infants are at increased risk of post-natal infection compared to their age-matched appropriately grown controls, in particular nosocomial infection, irrespective of the responsible pathogen. One possible mechanism is the retarded development in the immune system which has been described in association with IUGR. Indeed, SGA infants have a disproportionately small thymus and low leukocyte, lymphocyte and macrophage counts. However, immune therapies, including prophylactic intravenous immunoglobulins and GM-CSF have not proven to be effective in reducing the incidence of sepsis, and further research is required.
- Syphilitic hepatitis: an uncommon manifestation of a common disease. [Journal Article]
- Indian J Dermatol 2014 Mar; 59(2):209.
Hepatitis being first manifestation of secondary syphilis is rare. Here in we report a case of 39 years old male who was being treated for hepatitis and presented to us subsequently with itchy maculopapular rash. Venereal disease research laboratory (VDRL) titre was 1:16. Treponema pallidum hemagglutination assay (TPHA) was positive. He was treated with intramuscular Benzathine Penicillin. His hepatitis improved rapidly.