Gram-positive anaerobic bacilli in human periodontal disease

OBJECTIVE

The uncertain taxonomy of oral anaerobic gram-positive bacilli and their generally slow growing nature has limited the understanding of their role in periodontal disease. The current objective was to design and use species-specific oligonucleotide probes to investigate the relationship of selected gram-positive anaerobic bacilli to periodontal disease.

METHODS

Plaque and clinical measurements were collected from 40 patients with periodontitis and from 40 matched controls. Oligonucleotide probes were designed for Bulleidia extructa, Eubacterium nodatum, Mogibacterium timidum and Slackia exigua and used to probe nucleic acids extracted from the samples with a chemiluminescent detection method. Species were quantified as absent or present at low (approximately 10(3)-10(4) cells), medium (approximately 10(4)-10(5) cells) or high levels (approximately 10(5)-10(6) cells).

RESULTS

M. timidum and B. extructa were detected in only three and four samples, respectively. The level of both E. nodatum and S. exigua was significantly higher in deep than shallow pockets (Wilcoxon, p < 0.001). The level of E. nodatum, but not S. exigua, was higher in patients than matched controls (Mann-Whitney U, p < 0.03). Using an ordered logistic regression model, the probing depth of the sampled sites had the greatest influence on the level of both species and significant variations occurred between individuals. Bleeding also influenced the levels of both species, with supragingival plaque influencing S. exigua.

CONCLUSION

Both E. nodatum and S. exigua were associated with clinical indicators of periodontal disease.

Dialister invisus sp. nov., isolated from the human oral cavity

Six strains of anaerobic, Gram-negative coccobacilli isolated from the root canals of patients with endodontic infections (five strains) and from a deep periodontal pocket (one strain) were subjected to a comprehensive range of phenotypic and genetic tests and were found to comprise a homogeneous group. Following 16S rRNA gene sequence analysis, they were found to be most closely related to Dialister pneumosintes, with 93 % sequence similarity between the two taxa. A novel species, Dialister invisus sp. nov., is proposed. Biochemically, the species is largely unreactive and is asaccharolytic, with only traces of acetate and propionate detected as metabolic end-products. The G+C content of the DNA of D. invisus strains is 45-46 mol%. The type strain is E7.25(T) (=CCUG 47026(T)=DSM 15470(T)).

The clinical and microbiological effects of a novel acidified sodium chlorite mouthrinse on oral bacterial mucosal infections

Acidified sodium chlorite mouthrinses have been shown to have equivalent anti-plaque activity to those containing chlorhexidine, the current 'gold standard'. In this study, sodium chlorite mouthrinses (ASC) acidified with either malic or gluconic acids were compared to each other and with a chlorhexidine rinse and sterile water for their effect on salivary bacterial counts. Sixteen subjects participated in the study, which had a cross-over Latin square design. In a second study, a sodium chlorite/gluconic acid rinse was compared with chlorhexidine for its clinical and microbiological effects in 36 patients with oral mucosal infections. The sodium chlorite rinses acidified with malic and gluconic acids and the chlorhexidine rinse caused significant reductions in salivary bacterial counts up to 7 h after a single rinse compared with water. There were no significant differences between the three active treatments. In the mucosal infection study, there was a significant reduction in erythema in the chlorhexidine group compared with the ASC group. Patients who received the ASC rinse reported significantly less discomfort following treatment than those receiving the chlorhexidine rinse. Staphylococcus aureus counts were significantly reduced in the group who received the sodium chlorite rinse. There were no other significant differences between the treatments. ASC appears to be an effective alternative to chlorhexidine mouthrinse.

Characterization of novel human oral isolates and cloned 16S rDNA sequences that fall in the family Coriobacteriaceae: description of olsenella gen. nov., reclassification of Lactobacillus uli as Olsenella uli comb. nov. and description of Olsenella profusa sp. nov

The diversity of organisms present in the subgingival pockets of patients with periodontitis and acute necrotizing ulcerative gingivitis (ANUG) were examined previously. The 16S rRNA genes of subgingival plaque bacteria were amplified using PCR with a universal forward primer and a spirochaete-selective reverse primer. The amplified DNA was cloned into Escherichia coli. In one subject with ANUG, 70 clones were sequenced. Seventy-five per cent of the clones were spirochaetal, as expected. Twelve of the remaining clones fell into two clusters that represent novel phylotypes in the family Coriobacteriaceae. The first novel phylotype was most closely related to Atopobium rimae (98% similarity). The phylotype probably represents a novel Atopobium species, but will not be named until cultivable strains are obtained. The second novel phylotype was only 91% similar to described Atopobium species and 84% similar to Coriobacterium glomerans. The 16S rRNA sequences of the type strain of Lactobacillus uli and a strain representing the Moores' Eubacterium group D52 were determined as part of on ongoing sequence analysis of oral bacteria. The sequence for L. uli was more than 99.8% similar to sequences for the second clone phylotype. It therefore appears that the second clone phylotype and L. uli represent the same species. The sequence for the Eubacterium D52 strain was 95.6% similar to that of L. uli. The G+C content of the DNA of L. uli and Eubacterium D52 is 63-64 mol %. These organisms are thus distinct from the neighbouring genus Atopobium, which has a DNA G+C content of 35-46 mol%. A new genus, Olsenella gen. nov., is proposed for these two species on the basis of phenotypic characteristics and 16S rRNA sequence analysis to include Olsenella uli comb. nov. and Olsenella profusa sp. nov.

Bulleidia extructa gen. nov., sp. nov., isolated from the oral cavity

Five strains of anaerobic non-sporing Gram-positive bacilli isolated from advanced periodontitis (four strains) and a dentoalveolar abscess (one strain) that did not correspond to existing species were subjected to phenotypic and genetic characterization. Following 16S rDNA sequence analysis, they were found to constitute a novel branch of the low G+C Gram-positive division of the phylogenetic tree related to Erysipelothrix rhusiopathiae and Holdemania filiformis. A new genus Bulleidia, and the species Bulleidia extructa, are proposed. Growth of B. extructa in broth media was poor but was enhanced by the addition of fructose, glucose or maltose together with Tween 80. Glucose and maltose were fermented and arginine was hydrolysed. Acetate, lactate and trace amounts of succinate were the end products of glucose fermentation. The G+C content of the DNA of the type strain is 38 mol%. The type strain of Bulleidia extructa is DSM 13220T.

Evaluation of an electronic memory aid in the neuropsychological rehabilitation of prospective memory deficits

Five subjects with acquired memory impairment were trained to use a new electronic memory aid, the Voice Organizer, to manage prospective memory errors. Performance was assessed on two measures analogous to everyday memory tasks; a Message-Passing task requiring prospective recall after a delay of 9 hours, and a Domestic Task measure which involved the recall of household chores following a delay of 1-6 days. All subjects benefited from the introduction of the aid on the Message-Passing task and all but one improved their prospective recall on the Domestic Task measure. These results suggest that the Voice Organizer may be a useful aid in the neuropsychological rehabilitation of prospective memory impairment.

A new HLA-A*02 allele, A*0234, detected by polymerase chain reaction using sequence-specific primers (PCR-SSP)

A novel HLA-A*02 allele, A*0234, was identified in a potential unrelated bone marrow donor typed by polymerase chain reaction using sequence-specific primers (PCR-SSP). Positive reactions obtained upon testing with PCR-SSP did not fit any known combination of alleles indicating the possible presence of a novel allele. Sequencing of clones from this individual revealed the presence of a novel allele, HLA-A*0234. The sequence of exons 2, 3 and part of exon 4 showed that A*0234 differed from A*02011 by a single nucleotide in exon 2 at position 282 (C to G). The nucleotide substitution results in an amino acid change at residue 70 (Histidine to Glutamine) in the alpha1 domain.

Confirmation of the detection of HLA-A*0104N in a family: a PCR-SSP reaction for the allelic detection of HLA-A*0104N

The allele A*0104N has been detected in a family with a patient requiring a bone marrow transplant. The allele was found as a consequence of a discrepant result when family members were typed using serology and polymerase chain reaction using sequence-specific primers (PCR-SSP). Serological typing gave an apparent HLA-A 'blank' while PCR-SSP revealed the presence of an A*01 allele in three family members who were serologically negative for A1. Sequencing-based typing (SBT) was then used to establish that the allele was A*0104N. A PCR-SSP reaction was subsequently designed and used for the allelic detection of A*0104N. The study highlights the potential risks involved if molecular technology is used for typing, unless all non-expressed alleles are specifically detected.

Eubacterium minutum is an earlier synonym of Eubacterium tardum and has priority

The recently proposed species Eubacterium minutum and Eubacterium tardum appeared to be similar from their published descriptions. The aim of this study was to perform phenotypic and genetic analyses of strains of both species to clarify their taxonomic position. The type strains of E. minutum and E. tardum exhibited identical biochemical and protein profiles and their 16S rRNA gene sequences displayed 99.9% similarity. The G + C content of the DNA of both strains was estimated at 45 mol%. It is concluded that E. minutum and E. tardum are synonyms; E. minutum has priority. An emended description of E. minutum is given.

The family Coriobacteriaceae: reclassification of Eubacterium exiguum (Poco et al. 1996) and Peptostreptococcus heliotrinreducens (Lanigan 1976) as Slackia exigua gen. nov., comb. nov. and Slackia heliotrinireducens gen. nov., comb. nov., and Eubacterium lentum (Prevot 1938) as Eggerthella lenta gen. nov., comb. nov

16S rRNA gene sequences were determined for Eubacterium exiguum and Peptostreptococcus heliotrinreducens. These species were found to be closely related and, together with Eubacterium lentum, to constitute a branch of the Coriobacteriaceae. Two new genera are proposed on the basis of phenotypic characteristics and 16S rRNA gene sequence comparisons: Slackia to include the bile-sensitive species Eubacterium exiguum and P. heliotrinreducens, and Eggerthella to include the bile-resistant Eubacterium lentum. It is proposed that Eubacterium exiguum and Peptostreptococcus heliotrinreducens are transferred to the genus Slackia gen. nov. as Slackia exigua gen. nov., comb. nov. (type strain ATCC 700122T) and Slackia heliotrinireducens gen. nov., comb. nov. (type strain NTCC 11029T), respectively, and Eubacterium lentum is transferred to the genus Eggerthella gen. nov. as Eggerthella lenta gen. nov., comb. nov. with Eggerthella lenta as the type species.

Evaluating the benefits of a patient information video during the informed consent process

The study objective was to evaluate the effect of a patient information video during the informed consent process of a perinatal trial. Ninety women, between 19 and 33 weeks gestation, were randomised to receive written information about this perinatal trial and watch an information video or to receive written information only. Participants completed a questionnaire immediately after entry and 2-4 weeks later assessing knowledge of; feelings about the worth of; and willingness for future participation in the perinatal trial. When initially asked, more women who watched the video thought they would consent to the study (chi 2 = 6.3; df = 1; P = 0.01). No differences in knowledge about the perinatal trial were found initially, but 2-4 weeks later more knowledge had been retained by women who had watched the video (chi 2 = 6.7; df = 1; P = 0.01). These results suggest that a patient information video combined with an information sheet may result in greater participation in a research trial and may increase women's knowledge of a specific health problem and related research trial.

Adopt-A-School Program: recruitment initiative of New York Counties Registered Nurses Association. District 13 education committee

The goal of this program was to alleviate the existing nursing shortage in New York City by developing recruitment models appropriate for students in the City's high schools. The rationale was that well-informed nurses could create an attractive image of nursing by presenting programs to students, teachers, and guidance counselors. The program was successful in clarifying misconceptions and increasing the knowledge base regarding health issues and concerns and the role of the nurse.

Comparison of five methods, including the PDM Epsilometer test (E test), for antimicrobial susceptibility testing of Pseudomonas aeruginosa

The antimicrobial susceptibilities of 100 clinical isolates of Pseudomonas aeruginosa to six antipseudomonal antibiotics were tested by five methods: the National Committee for Clinical Laboratory Standards (NCCLS) methods for broth microdilution, agar dilution, and agar disk diffusion; the Vitek Automicrobic System method (Vitek Systems, Hazelwood, Mo.); and the PDM Epsilometer test (E test) (AB Biodisk, Solna, Sweden). The E test results showed excellent correlation with agar dilution results, with over 90% agreement within 1 doubling dilution between the E test and reference agar dilution MICs for all antimicrobial agents tested. The E test results also showed good correlation with the results from the reference agar disk diffusion method, with 90 to 99% complete agreement and 100% essential agreement on categories for all antibiotics tested (essential agreement is the agreement obtained when minor discrepancies are ignored). Comparison of categories with the E test and broth microdilution methods, using the broth microdilution method as the reference method, gave only 59% complete agreement for gentamicin, with 28 minor discrepancies and 13 very major discrepancies. Some discrepancies were observed between results from the E test and broth methods for gentamicin, with the broth microdilution and Vitek methods giving higher MICs than the E test and other methods using agar. The most recent NCCLS guidelines for broth dilution testing have reduced the recommended levels of cation supplementation, which may enhance future agreement between results for the aminoglycosides and P. aeruginosa on broth and on agar. We found that the E test offers a simple, labor-efficient, and accurate method for MIC determination on an agar medium.

Comparison of the Sceptor Pseudomonas Plus MIC Panel with agar dilution for susceptibility testing of Pseudomonas aeruginosa

The antimicrobial susceptibilities of 100 clinical isolates of Pseudomonas aeruginosa to gentamicin, amikacin, tobramycin, ticarcillin, piperacillin, and ceftazidime were determined by using the Sceptor system (BBL Microbiology Systems, Cockeysville, Md.), and the results were compared with those obtained using the National Committee for Clinical Laboratory Standards reference agar dilution method. Excellent correlation was observed for the aminoglycosides, with greater than 95% agreement within 1 doubling dilution of the reference agar dilution MIC, while ticarcillin and piperacillin showed lower percent agreement values of 91 and 88%, respectively.

Development of aldehyde dehydrogenase and alcohol dehydrogenase in mouse eye: evidence for light-induced changes

We have studied the development of ocular aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) activities in C57BL/6J inbred male mice. Eyes were removed from freshly killed mice, enucleated, extracted, and analyzed for enzyme activities for animals of various ages during neonatal development, up to the adult stage. Activity levels were compared between mice maintained from birth in either complete darkness or on a 12-hour light/dark cycle. Ocular ALDH activity increased dramatically (greater than 30-fold) during the first 3 weeks of life. Moreover, light-adapted animals showed significantly higher ALDH activities from day 8. Ocular ADH activity also increased during development (greater than 5-fold) although the profile showed a steady increase to reach adult levels. Light-adapted mice showed no significant differences in ADH activity up to the weaning stage, as compared with mice maintained in darkness. These observations support proposals from earlier studies for major functional roles for both corneal ALDH and ADH in protecting the eye against ultraviolet light-induced damage.

Acquired immunodeficiency syndrome: the nurse's legal duty to serve

Some nurses are reluctant to care for human immunodeficiency virus (HIV)-infected clients because of fear of contagion and discomfort in caring for people with alternate life-styles. Various federal, state, and local antidiscrimination statutes limit the right of the nurse to refuse to care for people with acquired immunodeficiency syndrome (AIDS) or HIV infection. Other constraints are employment contracts, ethical codes of professional organizations, and regulations of state licensing boards. Nurses have rights as well as responsibilities in caring for AIDS or HIV-infected patients. They also have a professional responsibility to institute measures that minimize the need for litigation and ensure access to health care for everyone.

Evaluation of two single-plate incubation systems and the anaerobic chamber for the cultivation of anaerobic bacteria

Three systems that are available for the incubation of anaerobic organisms were evaluated to assess their ability to support the growth of 25 anaerobic stock strains and to successfully recover anaerobic bacteria from clinical specimens. These were the anaerobic chamber, the Anaerobic Pouch System Catalyst-Free (Difco Laboratories, Detroit, Mich.), and the Bio-Bag Environmental Chamber Type A (Marion Scientific, Div. Marion Laboratories, Inc., Kansas City, Mo.). Three study centers were involved, the Wadsworth Anaerobe Laboratory (Los Angeles, Calif.), the Good Samaritan Hospital (San Jose, Calif.), and the Massachusetts General Hospital (Boston). A total of 171 anaerobic organisms were isolated from 49 clinical specimens that were cultured at the three test centers. Of these, 169 (99%) were recovered from media that were incubated in the anaerobic chamber, 163 (95%) were recovered from the Anaerobic Pouch, and 147 (86%) were recovered from the Bio-Bag. A similar trend was seen with the stock strains, in which the anaerobic chamber often supported better growth of the organisms than did either of the bag systems.

Bilophila wadsworthia, gen. nov. and sp. nov., a unique gram-negative anaerobic rod recovered from appendicitis specimens and human faeces

Strongly catalase-positive Gram-negative anaerobic rods were isolated from approximately half of all intra-abdominal specimens received from patients with gangrenous and perforated appendicitis, and subsequently also from normal faecal specimens. The organism was originally detected on Bacteroides-bile-aesculin (BBE) agar, and grew slowly on non-selective anaerobic media containing blood. It was stimulated by bile and differed from other known genera by being urease- and catalase-positive, and by reducing nitrate. It did not reduce sulphate. Other anaerobic Gram-negative rods showed no homology by DNA dot-blot hybridization. The thermal melting profile of chromosomal DNA showed 39-40 mol% G + C. The whole-cell fatty acid methyl ester profile included cyclic and branched long-chain acids, and differed from those of all other anaerobes that have been tested. beta-Lactamase was not detected. The name Bilophila wadsworthia gen. nov., sp. nov. is proposed for this organism.

Evaluation of the RapID ANA system as a four-hour method for anaerobe identification

The RapID ANA system (Innovative Diagnostic Systems Inc., Atlanta, Ga, USA), a 4-hour micromethod for identifying clinically important anaerobic bacteria, was evaluated using 196 anaerobic clinical isolates and the results were compared with those obtained by applying conventional Virginia Polytechnic Institute (VPI) methodology. The identifications achieved by the RapID ANA system for 141 (72%) of these isolates agreed with the species identifications obtained using VPI methodology, without the need for additional tests. A further 40 (20%) were in agreement after performance of additional suggested tests, 11 (6%) were misidentified and 4 (2%) could not be identified using the RapID ANA system. Excellent agreement between the two methods was demonstrated for the Gram-positive cocci and good agreement for the Gram-negative bacilli. The RapID ANA system was suboptimal in the identification of Clostridium species other than C. perfringens.

Susceptibility of 114 isolates of the Bacteroides fragilis group to imipenem and eight other antimicrobial agents

The minimal inhibitory concentrations (MICs) of the newer beta-lactam antibiotic, imipenem, were compared with those of cefoxitin, cefotetan, penicillin, amoxycillin, ticarcillin and metronidazole against 114 clinical isolates of the Bacteroides fragilis group of anaerobic organisms. The ability of clavulanic acid, a beta-lactamase inhibitor, to potentiate the in vitro activity of amoxycillin and ticarcillin was also studied. Using an agar dilution technique we found imipenem to be the most active beta-lactam antibiotic tested having an MIC50 of 0.25 microgram/ml and inhibiting all isolates at a concentration of 4 micrograms/ml. Metronidazole had comparable activity with a MIC50 of 0.5 microgram/ml and all isolates inhibited by 1 microgram/ml. Cefoxitin and cefotetan showed similar activity both with a MIC50 of 8 micrograms/ml against the B. fragilis group, while penicillin, amoxycillin and ticarcillin all had a MIC50 of 16 micrograms/ml. Clavulanic acid significantly reduced the MIC50 of amoxycillin and ticarcillin to 0.5 micrograms/ml and 0.25 micrograms/ml, respectively.

Rating reliability for life events and difficulties in the elderly

The inter-rater reliability of Brown's measure of ongoing difficulties ('severity') is shown to be comparable with that of the measure of life events ('long-term threat') when using data from an elderly subject pool. Test-retest reliabilities for both the life event and difficulty measures are shown to be adequate if based on 'consensus' ratings. The question is raised of generalizability of the concepts of 'threat' and 'severity' across the lifespan.

A comparison of selective media for the isolation of anaerobic bacteria from clinical material

Clinical specimens submitted for anaerobic culture to a Melbourne teaching hospital microbiology laboratory were plated onto 3 types of selective media, to determine which would allow the optimal recovery of anaerobic organisms. The 3 media employed were kanamycin agar (KA), neomycin agar (NA) and nalidixic acid-Tween 80 agar (NAT). The highest isolation rate was achieved on NAT, 89% of the total of all anaerobes isolated being recovered on this medium. A recovery rate of 69% was achieved using NA, while use of KA allowed the isolation of only 56% of all strains. The major difference between 3 media was in the recovery of anaerobic Gram-positive cocci, which accounted for 40% of the total isolates on NAT, 25% on NA, and only 11% on KA. The NAT was also more successful in the isolation of Fusobacterium and Veillonella species. The NAT medium failed, however, to recover Clostridium spp. that were isolated on both NA and KA. There was no significant difference between the 3 media in regard to the recovery of Bacteroides spp.

Experimental infection of man with rabbit-virulent Treponema paraluis-cuniculi

Virulent Treponema paraluis-cuniculi was inoculated intradermally into the arm of a human volunteer and into the shaved backs of 10 rabbits. An identical, but heat-killed, preparation was inoculated into the opposite arm of the volunteer as control. A superficial and transient infection developed in the volunteer, shown by a small zone of erythema that persisted for 24 days. The control preparation caused a smaller zone of erythema that disappeared after five days. A very poor immune response was detected by standard serological tests for syphilis. The inoculated rabbits developed lesions about six days after infection and seroconverted by 84 days. The poor antitreponemal antibody response to T paraluis-cuniculi infection in the volunteer suggests that this naturally attenuated treponeme may not be suitable as a vaccine against infection with t pallidum in humans.