It has been recognized for some time that bacterial species exist in complexes in subgingival plaque. The purpose of the present investigation was to attempt to define such communities using data from large numbers of plaque samples and different clustering and ordination techniques. Subgingival plaque samples were taken from the mesial aspect of each tooth in 185 subjects (mean age 51 +/- 16 years) with (n = 160) or without (n = 25) periodontitis. The presence and levels of 40 subgingival taxa were determined in 13,261 plaque samples using whole genomic DNA probes and checkerboard DNA-DNA hybridization. Clinical assessments were made at 6 sites per tooth at each visit. Similarities between pairs of species were computed using phi coefficients and species clustered using an averaged unweighted linkage sort. Community ordination was performed using principal components analysis and correspondence analysis. 5 major complexes were consistently observed using any of the analytical methods. One complex consisted of the tightly related group: Bacteroides forsythus, Porphyromonas gingivalis and Treponema denticola. The 2nd complex consisted of a tightly related core group including members of the Fusobacterium nucleatum/periodonticum subspecies, Prevotella intermedia, Prevotella nigrescens and Peptostreptococcus micros. Species associated with this group included: Eubacterium nodatum, Campylobacter rectus, Campylobacter showae, Streptococcus constellatus and Campylobacter gracilis. The 3rd complex consisted of Streptococcus sanguis, S. oralis, S. mitis, S. gordonii and S. intermedius. The 4th complex was comprised of 3 Capnocytophaga species, Campylobacter concisus, Eikenella corrodens and Actinobacillus actinomycetemcomitans serotype a. The 5th complex consisted of Veillonella parvula and Actinomyces odontolyticus. A. actinomycetemcomitans serotype b, Selenomonas noxia and Actinomyces naeslundii genospecies 2 (A. viscosus) were outliers with little relation to each other and the 5 major complexes. The 1st complex related strikingly to clinical measures of periodontal disease particularly pocket depth and bleeding on probing.

Microbial complexes in subgingival plaque

Gut microbiota is an assortment of microorganisms inhabiting the length and width of the mammalian gastrointestinal tract. The composition of this microbial community is host specific, evolving throughout an individual's lifetime and susceptible to both exogenous and endogenous modifications. Recent renewed interest in the structure and function of this "organ" has illuminated its central position in health and disease. The microbiota is intimately involved in numerous aspects of normal host physiology, from nutritional status to behavior and stress response. Additionally, they can be a central or a contributing cause of many diseases, affecting both near and far organ systems. The overall balance in the composition of the gut microbial community, as well as the presence or absence of key species capable of effecting specific responses, is important in ensuring homeostasis or lack thereof at the intestinal mucosa and beyond. The mechanisms through which microbiota exerts its beneficial or detrimental influences remain largely undefined, but include elaboration of signaling molecules and recognition of bacterial epitopes by both intestinal epithelial and mucosal immune cells. The advances in modeling and analysis of gut microbiota will further our knowledge of their role in health and disease, allowing customization of existing and future therapeutic and prophylactic modalities.

Gut Microbiota in Health and Disease

Recent years have witnessed the rise of the gut microbiota as a major topic of research interest in biology. Studies are revealing how variations and changes in the composition of the gut microbiota influence normal physiology and contribute to diseases ranging from inflammation to obesity. Accumulating data now indicate that the gut microbiota also communicates with the CNS — possibly through neural, endocrine and immune pathways — and thereby influences brain function and behaviour. Studies in germ-free animals and in animals exposed to pathogenic bacterial infections, probiotic bacteria or antibiotic drugs suggest a role for the gut microbiota in the regulation of anxiety, mood, cognition and pain. Thus, the emerging concept of a microbiota-gut-brain axis suggests that modulation of the gut microbiota may be a tractable strategy for developing novel therapeutics for complex CNS disorders.

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Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour

The importance of the gut-brain axis in maintaining homeostasis has long been appreciated. However, the past 15 yr have seen the emergence of the microbiota (the trillions of microorganisms within ...

The Microbiota-Gut-Brain Axis

The majority of dermal wounds are colonized with aerobic and anaerobic microorganisms that originate predominantly from mucosal surfaces such as those of the oral cavity and gut. The role and significance of microorganisms in wound healing has been debated for many years. While some experts consider the microbial density to be critical in predicting wound healing and infection, others consider the types of microorganisms to be of greater importance. However, these and other factors such as microbial synergy, the host immune response, and the quality of tissue must be considered collectively in assessing the probability of infection. Debate also exists regarding the value of wound sampling, the types of wounds that should be sampled, and the sampling technique required to generate the most meaningful data. In the laboratory, consideration must be given to the relevance of culturing polymicrobial specimens, the value in identifying one or more microorganisms, and the microorganisms that should be assayed for antibiotic susceptibility. Although appropriate systemic antibiotics are essential for the treatment of deteriorating, clinically infected wounds, debate exists regarding the relevance and use of antibiotics (systemic or topical) and antiseptics (topical) in the treatment of nonhealing wounds that have no clinical signs of infection. In providing a detailed analysis of wound microbiology, together with current opinion and controversies regarding wound assessment and treatment, this review has attempted to capture and address microbiological aspects that are critical to the successful management of microorganisms in wounds.

Wound microbiology and associated approaches to wound management.

Comparison of recovery of anaerobic bacteria using the Anoxomat, anaerobic chamber, and GasPak jar systems.

Overnight mail delivery was evaluated for its effect on the recovery of facultative and anaerobic microbes in cultures of clinical specimens from patients. Ten clinical specimens, which were collected at different geographic locations and during different weather conditions, were cultured at the site and after overnight delivery to a distant laboratory. Forty-five facultative anaerobic isolates and 48 anaerobes were recovered. There was no significant difference in numbers of strains or relative quantities recovered in cultures of transported and nontransported specimens. With proper collection, transport, and inoculation of specimens, overnight delivery did not compromise recovery of clinically relevant microbes.

Survival of anaerobes in original specimens transported by overnight mail services

During our studies of the bacterial etiology of appendicitis, we often isolated a previously undescribed anaerobic gram-negative rod. This organism resembled the Bacteroides fragilis group because it was resistant to bile and because of its special-potency-disk pattern (resistant to vancomycin, kanamycin, and colistin), but unlike the B. fragilis group, this bacterium produced brown pigment on media containing hemolysed blood. The cellular fatty acid pattern, with iso-C15:0 being the predominant acid, was most closely related to the fatty acid profile of Porphyromonas species; however, this organism differed from Porphyromonas species by being bile-resistant and by not producing butyrate as a metabolic endproduct. Enzymatic activities of 31 isolates were determined with use of the API ZYM system and Rosco diagnostic tablets. These profiles were different from those of Prevotella, Porphyromonas, and related species. This organism was isolated from 40% of appendiceal tissue samples; no obvious qualitative or quantitative difference in rates of isolation from patients with inflamed or normal appendices was observed.

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Characteristics of an Unusual Anaerobic Pigmented Gram-Negative Rod Isolated from Normal and Inflamed Appendices

Cellular Fatty Acid Analysis and Enzyme Profiles ofPorphyromonas catoniae— a Frequent Colonizer of the Oral Cavity in Children

Porphyromonas endodontalis has been isolated almost exclusively from the oral cavity. P. endodontalis is a key pathogen in endodontic infections such as infected root canals and abscesses [1]. We report herein the isolation of P. endodontalis-like organisms (PELOs) from extraoral sources. These organisms have a close phenotypic resemblance to oral isolates of P. endodontalis; however, their taxonomic position warrants reassessment. The aim of this study was to describe the isolation and characterization of PELOs and the laboratory tests useful in their identification. Six PELO isolates recovered in fecal specimens from young children, as well as six strains that originated from extraoral clinical specimens from adult patients (from the Wadsworth Anaerobic Bacteriology Laboratory [WAL; West Los Angeles, CA] collection) and P. endodontalis ATCC (American Type Culture Collection) 35406T, were included in the bacteriologic study. Five other P. endodontalis strains isolated from oral sources, five Porphyromonas asaccharolytica strains, and P. asaccharolytica ATCC 25260T were also included in the cellular-fatty-acid analyses (table 1). The fecal strains were isolated during a microbiological study of antimicrobial agent-associated flora changes. The fecal samples were inoculated on various selective and nonselective media with use of quantitative culture techniques [2]. To isolate PELOs, we used Brucella blood agar and kanamycin/vancomycin laked blood (KVLB) agar and phenylethyl alcohol (PEA) blood agar plates incubated anaerobically for 5-10 days. The clinical WAL strains were characterized during a comprehensive reevaluation of pigmented gram-negative rods. We characterized the strains by using routine biochemical tests [2], special-potency antibiotic identification disks, prereduced anaerobically sterilized biochemicals, gas liquid chromatography, API ZYM (bioMerieux, Marcy l'Etoile, France) panels, and Rosco Diagnostic Tablets (Rosco, Taastrup, Denmark). The production of /-lactamase was detected with use of the nitrocefin disk test (Nitrocefin, BIODISK, Solna, Sweden). Cellular fatty acids were detected by a Hewlett Packard (Palo Alto, CA) 5890 series II gas chromatograph and the Microbial Identification System software (Microbial ID, Newark, DE). The isolates were grown on supplemented brain heart infusion agar with blood, and the bacterial mass was harvested directly from the plates because of poor growth in liquid media. The corresponding library (Microbial ID, ANAEROBE version 3.8) was used in successive analyses. The identity of fatty acids was confirmed by combined gas chromatographymass spectrometry. A cluster analysis, expressed as a dendrogram, was run by the program included in the MIDI software. The sources of PELOs in clinical specimens were appendiceal tissue or peritoneal fluid (three specimens), an infected sacral de-

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Marja-Liisa Väisänen

Papers

Comparison of recovery of anaerobic bacteria using the Anoxomat, anaerobic chamber, and GasPak jar systems.

Survival of anaerobes in original specimens transported by overnight mail services

Characteristics of an Unusual Anaerobic Pigmented Gram-Negative Rod Isolated from Normal and Inflamed Appendices

Cellular Fatty Acid Analysis and Enzyme Profiles ofPorphyromonas catoniae— a Frequent Colonizer of the Oral Cavity in Children

Porphyromonas endodontalis-Like Organisms from Extraoral Sources