Long-Term In Vitro Culture of the Syphilis Spirochete Treponema pallidum subsp. pallidum

Investigation of Treponema pallidum subsp. pallidum, the spirochete that causes syphilis, has been hindered by an inability to culture the organism continuously in vitro despite more than a century of effort. In this study, long-term logarithmic multiplication of T. pallidum was attained through subculture every 6 to 7 days and periodic feeding using a modified medium (T. pallidum culture medium 2 [TpCM-2]) with a previously described microaerobic, rabbit epithelial cell coincubation system. Currently, cultures have maintained continuous growth for over 6 months with full retention of viability as measured by motility and rabbit infectivity. This system has been applied successfully to the well-studied Nichols strain of T. pallidum, as well as to two recent syphilis isolates, UW231B and UW249B. Light microscopy and cryo-electron microscopy showed that in vitro-cultured T. pallidum retains wild-type morphology. Further refinement of this long-term subculture system is expected to facilitate study of the physiological, genetic, pathological, immunologic, and antimicrobial susceptibility properties of T. pallidum subsp. pallidum and closely related pathogenic Treponema species and subspecies.IMPORTANCE Syphilis, a sexually transmitted disease with a global distribution, is caused by a spiral-shaped bacterium called Treponema pallidum subspecies pallidum Previously, T. pallidum was one of the few major bacterial pathogens that had not been cultured long-term in vitro (in a test tube), greatly hindering efforts to better understand this organism and the disease that it causes. In this article, we report the successful long-term cultivation of T. pallidum in a tissue culture system, a finding that is likely to enhance our ability to obtain new information applicable to the diagnosis, treatment, and prevention of syphilis.

Sequence Variation of Rare Outer Membrane Protein β-Barrel Domains in Clinical Strains Provides Insights into the Evolution of Treponema pallidum subsp. pallidum, the Syphilis Spirochete

In recent years, considerable progress has been made in topologically and functionally characterizing integral outer membrane proteins (OMPs) of Treponema pallidum subspecies pallidum, the syphilis spirochete, and identifying its surface-exposed β-barrel domains. Extracellular loops in OMPs of Gram-negative bacteria are known to be highly variable. We examined the sequence diversity of β-barrel-encoding regions of tprC, tprD, and bamA in 31 specimens from Cali, Colombia; San Francisco, California; and the Czech Republic and compared them to allelic variants in the 41 reference genomes in the NCBI database. To establish a phylogenetic framework, we used T. pallidum 0548 (tp0548) genotyping and tp0558 sequences to assign strains to the Nichols or SS14 clades. We found that (i) β-barrels in clinical strains could be grouped according to allelic variants in T. pallidum subsp. pallidum reference genomes; (ii) for all three OMP loci, clinical strains within the Nichols or SS14 clades often harbored β-barrel variants that differed from the Nichols and SS14 reference strains; and (iii) OMP variable regions often reside in predicted extracellular loops containing B-cell epitopes. On the basis of structural models, nonconservative amino acid substitutions in predicted transmembrane β-strands of T. pallidum repeat C (TprC) and TprD2 could give rise to functional differences in their porin channels. OMP profiles of some clinical strains were mosaics of different reference strains and did not correlate with results from enhanced molecular typing. Our observations suggest that human host selection pressures drive T. pallidum subsp. pallidum OMP diversity and that genetic exchange contributes to the evolutionary biology of T. pallidum subsp. pallidum They also set the stage for topology-based analysis of antibody responses to OMPs and help frame strategies for syphilis vaccine development.IMPORTANCE Despite recent progress characterizing outer membrane proteins (OMPs) of Treponema pallidum, little is known about how their surface-exposed, β-barrel-forming domains vary among strains circulating within high-risk populations. In this study, sequences for the β-barrel-encoding regions of three OMP loci, tprC, tprD, and bamA, in T. pallidum subsp. pallidum isolates from a large number of patient specimens from geographically disparate sites were examined. Structural models predict that sequence variation within β-barrel domains occurs predominantly within predicted extracellular loops. Amino acid substitutions in predicted transmembrane strands that could potentially affect porin channel function were also noted. Our findings suggest that selection pressures exerted within human populations drive T. pallidum subsp. pallidum OMP diversity and that recombination at OMP loci contributes to the evolutionary biology of syphilis spirochetes. These results also set the stage for topology-based analysis of antibody responses that promote clearance of T. pallidum subsp. pallidum and frame strategies for vaccine development based upon conserved OMP extracellular loops.

An In Vitro Blood-Feeding Method Revealed Differential Borrelia turicatae (Spirochaetales: Spirochaetaceae) Gene Expression After Spirochete Acquisition and Colonization in the Soft Tick Ornithodoros turicata (Acari: Argasidae)

In the Midwestern, Southwestern, and Southern part of the United States, the soft tick Ornithodoros turicata transmits the spirochete Borrelia turicatae, the causative agent of relapsing fever in humans. In this study, we report a simplified and an efficient method of in vitro feeding to evaluate O. turicata-B. turicatae interactions. Both nymphal and adult female ticks successfully acquired spirochetes upon in vitro feeding on the B. turicatae-infected blood. We also noted transstadial transmission of spirochetes to adult ticks that were molted from nymphs fed on B. turicatae-infected blood. A differential expression pattern for some of the B. turicatae genes was evident after acquisition and colonization of the vector. The levels of arthropod-associated lipoprotein Alp-mRNA were significantly upregulated and the mRNA levels of factor H binding protein FhbA and immunogenic protein BipA were significantly downregulated in the spirochetes after acquisition into ticks in comparison with spirochetes grown in culture medium. In addition, genes such as bta124 and bta116 were significantly upregulated in spirochetes in unfed ticks in comparison with the levels noted in spirochetes after acquisition. These findings represent an efficient in vitro blood-feeding method to study B. turicatae gene expression after acquisition and colonization in these ticks. In summary, we report that B. turicatae survive and develop in the tick host when acquired by in vitro feeding. We also report that B. turicatae genes are differentially expressed in ticks in comparison with the in vitro-grown cultures, indicating influence of tick environment on spirochete gene expression.

Novel spirochetes isolated from mosquitoes and black flies in the Czech Republic

During the years 1999-2002, a total of 4,898 individuals of 26 species of hematophagous insects (4,149 mosquitoes, 583 black flies, and 166 tabanid flies) was examined for the presence of spirochetes using dark-field microscopy. There was an overall recovery of spirochetes from the midguts of Culicidae and Simuliidae of 23.5% and 11.4%, respectively. Spirochetes were not detected in Tabanidae. Seven spirochetal strains have been successfully recovered from mosquitoes and black flies: BR149 (Culex pipiens), BR151 (Cx. pipiens), BR173 (Cx. pipiens), BR177 (Cx. pipiens), BR193 (Aedes cinereus), BR208 (Cx. pipiens), and BR231 (Simulium noelleri). The strains have been adapted to laboratory conditions (BSK-H Complete medium). Their preliminary determination based on 16S rRNA gene sequencing has shown that they differ from the Lyme disease spirochete Borrelia burgdorferi sensu lato as well as other members of the Order Spirochaetales indicating novel bacterial species in the Family Spirochaetaceae.

A Clinical, Radiographic, and Microbiologic Comparison of Astra Tech and Brånemark Single Tooth Implants

BACKGROUND

The soft tissues around single tooth implants differ fundamentally from the gingiva around natural teeth. There are very limited data comparing soft tissues around different implant systems.

AIM

To assess whether the design characteristics of dental implants, particularly the implant-abutment junction, may affect the dimensions and health of the peri-implant soft tissues and radiographic bone levels.

SUBJECTS AND METHOD

Fifteen Astra Tech and 15 Brånemark single tooth implants that had been in function for a minimum of 2 years in 30 partially dentate subjects were examined for plaque accumulation, probing depth, and bleeding on probing and compared to contralateral healthy teeth. Standardized radiographs were taken to measure the most coronal bone to implant contact on the mesial and distal surfaces. In addition, samples of subgingival plaque were taken on paper points and examined by darkfield microscopy.

RESULTS

Significantly higher mean probing depths (p < .001) and higher mean percentage of spirochetes (p = .003) were found at implants compared to teeth. In this sample, the Brånemark implants had significantly higher probing depths than the Astra Tech implants (median and interquartile range: Astra Tech 2.7 mm [2-3], Brånemark 3.3 mm [3-3.7] p = .026) and the most coronal bone to implant contact was closer to the implant-abutment junction in the Astra Tech implants (Astra Tech 0.6 mm [0.2-0.9], Brånemark 1.6 mm [1.4-2.0]. p < .001).

CONCLUSION

Although there were statistically significant differences between the two implant systems, the clinical differences were small and probably reflect differences in the biologic width in relation to the location and design of the implant-abutment junction.

Quality-control ranges for antimicrobial susceptibility testing by broth dilution of the Brachyspira hyodysenteriae type strain (ATCC 27164T)

There are no approved standards for antimicrobial susceptibility testing of the fastidious spirochete Brachyspira hyodysenteriae. An interlaboratory study was performed to establish MIC quality control ranges for six antimicrobial agents for the type strain of B. hyodysenteriae using broth dilution. The results showed that B. hyodysenteriae B78T ATCC 27164T is a suitable quality control strain. This is a first step toward standardization of methods regarding this anaerobe.

The effect of fermentable carbohydrates on experimental swine dysentery and whip worm infections in pigs

An experiment was conducted to study the effect of diets with contrasting fermentability in the large intestine on experimental infections with Brachyspira hyodysenteriae, the causative agent of swine dysentery, and the whip worm, Trichuris suis, in pigs. Two diets with organically grown ingredients were composed. Both diets were based on triticale and barley and supplemented with either rape seed cake (Diet 1) or dried chicory root and sweet lupins (Diet 2). The study had a three-factorial design, with eight groups of pigs receiving Diet 1 or Diet 2, +/-B. hyodysenteriae, and +/-T. suis. Pigs fed Diet 2 and challenged with B. hyodysenteriae did not develop swine dysentery and B. hyodysenteriae was not demonstrated in any of the pigs during the study. In contrast, 94% of the B. hyodysenteriae challenged pigs fed Diet 1 showed clinical symptoms of swine dysentery and all the pigs were shedding B. hyodysenteriae in faeces at some points in time during the experiment. The number of T. suis was lower in pigs fed Diet 2 compared to pigs fed Diet 1, but the differences were not significant. Pigs on Diet 1 and challenged with both pathogens showed clinical symptoms of SD for a longer period than pigs inoculated with B. hyodysenteriae only. The study showed that diets supplemented with highly fermentable carbohydrates from dried chicory roots and sweet lupins can protect pigs against developing swine dysentery, but do not have any significant influence on T. suis.

Spherical body formation in the spirochaeteBrachyspira hyodysenteriae

When cultures of Brachyspira hyodysenteriae were grown under a wide range of in vitro conditions, at least 1% of the cells formed spherical bodies different to the normal helical form. This percentage increased considerably in aging cultures or following their incubation in caramelized media. Spherical body formation was initiated from a terminal localized swelling of the outer sheath followed by a retraction of the protoplasmic cylinder into the resulting swollen vesicle. As this occurred, the periplasmic flagella seemed to unwind from the protoplasmic cylinder. Once retracted, the protoplasmic cylinder was found to be wrapped in an organized manner around the inner surface of the membrane of the swollen vesicle. Although most were 2-3 microm in diameter, some much larger spherical bodies (6-12 microm diameter) were occasionally seen, with a corresponding increase in the visible number of peripheral protoplasmic cylinder cross-sections. Spherical bodies from older cultures did not contain protoplasmic cylinders arranged around the periphery, but instead were characterized by the presence of a centrally located, electron-dense body c. 0.5-0.8 mum in diameter. Brachyspira hyodysenteriae spherical bodies differ in both their structural organization and probable method of formation from similar structures described in other spirochaete genera.

Immunopathological investigations on bovine digital epidermitis

Paraffin-embedded fragments of bovine digital skin lesions were sectioned and stained with Warthin-Starry, haematoxylin and eosin, Grocott's methenamine silver and immunohistochemical techniques. Microorganisms observed in the silver-stained sections were classified into four major morphological groups. Spirochaetes were the most prevalent organisms, but bacillary and coccoid elements were also present in most sections. Immunohistochemical probing demonstrated that approximately 80 per cent, 46 per cent and 41 per cent of the digital and interdigital dermatitis sections stained positively with polyclonal antisera to Treponema pallidum, Campylobacter jejuni and Fusobacterium necrophorum, respectively. An unidentified branching filamentous organism (presumed to be an actinomycete) was consistently present in the sections of samples from mild interdigital lesions.

In vitro susceptibility and a new point mutation associated with tylosin-resistance in Japanese canine intestinal spirochetes

The in vitro susceptibilities of six commonly used antimicrobial agents against 29 isolates of intestinal spirochetes isolated from dogs in Japan were examined by the agar dilution technique. In addition, the genetic basis of tylosin resistance in in vitro selected resistant mutants of two reference strains and three tylosin-susceptible field isolates obtained by three successive subcultures on blood agar containing 1 microg/ml of tylosin was investigated. Carbadox was the most active (MIC: < 0.00625) of all the antimicrobial agents. Although all the isolates were susceptible to tylosin, some were resistant to erythromycin. Tiamulin, lincomycin and dimetridazole were also very active against the isolates. All the resistant isolates did not harbor any plasmids. In vitro selected tylosin-resistant mutants of previously tylosin-susceptible isolates showed a new mutation in which their adenine at the base position equivalent to 2062 of 23S rDNA of Escherichia coli has been replaced by cytosine. These findings may both provide guidance towards the proper choice of antimicrobial agents for the treatment of canine intestinal spirochetosis, and add to the understanding of the genetic basis of tylosin resistance.

Development of a duplex PCR assay for detection of Brachyspira hyodysenteriae and Brachyspira pilosicoli in pig feces

A duplex PCR (D-PCR) amplifying portions of the Brachyspira hyodysenteriae NADH oxidase gene and the B. pilosicoli 16S rRNA gene was developed and then tested on DNA extracted from 178 porcine fecal samples. The feces also underwent anaerobic culture and species-specific PCRs. Fecal extraction-D-PCR detected seven additional samples containing B. hyodysenteriae and five more containing B. pilosicoli.

Evaluation of selective media for the isolation of Brachyspira aalborgi from human faeces

The purposes of this study were to identify a solid medium that supports improved growth of the anaerobic intestinal spirochaete Brachyspira aalborgi, to modify this for use as a selective isolation medium and then to test the medium for its effectiveness in isolating B. aalborgi from patients' faeces. Of the media evaluated, brain heart infusion agar (BHIA) with 10 % bovine blood (BB) was the most effective base-supplement combination for growth, with colonies attaining 1.2 mm in diameter by 21 days. Incubation in an anaerobic jar (94 % H(2), 6 % CO(2)) permitted growth of larger colonies than incubation in an anaerobic chamber (80 % N(2), 10 % H(2), 10 % CO(2)). Growth was improved only slightly at 38.5 degrees C compared with 37 degrees C. Selection of B. aalborgi from artificially seeded faeces was achieved equally well on eight different solid media containing spectinomycin (400 micro g ml(-1)) alone or in combinations with polymyxin B (5 micro g ml(-1)), colistin (25 micro g ml(-1)) and rifampicin (12.5 micro g ml(-1)). By using BHIA 10 % BB with spectinomycin plus polymyxin B, B. aalborgi was isolated from one of five human faecal samples that were positive for B. aalborgi by PCR amplification. This is the first report of the isolation of B. aalborgi from human faeces.

Relapsing fever-like spirochetes infecting European vector tick of Lyme disease agent

To determine whether relapsing fever-like spirochetes associated with hard ticks may infect Ixodes ricinus ticks in central Europe, we screened questing ticks for 16S rDNA similar to that of Asian and American relapsing fever-like spirochetes. We compared the prevalence of these spirochetes to that of Lyme disease spirochetes transmitted by the same vector. Relapsing fever-like spirochetes infect 3.5% of questing vector ticks in our three central European sites near the Rhein Valley. These spirochetes differ genetically from their American and Asian analogs while being relatively homogeneous in the region we sampled. The Lyme disease genospecies most commonly detected in central Europe are distributed broadly, whereas those that are less frequently found appear to be place-specific. The absence of co-infected ticks suggests that relapsing fever-like and Lyme disease spirochetes may not share hosts. Exposure risk for relapsing fever-like spirochetes is similar to that of certain Lyme disease genospecies. Although many persons may be bitten by ticks infected by relapsing fever-like spirochetes, health implications remain unknown.

Termite symbiotic systems: efficient bio-recycling of lignocellulose

Termites thrive in great abundance in terrestrial ecosystems and play important roles in biorecycling of lignocellulose. Together with their microbial symbionts, they efficiently decompose lignocellulose. In so-called lower termites, a dual decomposing system, consisting of the termite's own cellulases and those of its gut protists, was elucidated at the molecular level. Higher termites degrade cellulose apparently using only their own enzymes, because of the absence of symbiotic protists. Termite gut prokaryotes efficiently support lignocellulose degradation. However, culture-independent molecular studies have revealed that the majority of these gut symbionts have not yet been cultivated, and that the gut symbiotic community shows a highly structured spatial organization. In situ localization of individual populations and their functional interactions are important to understand the nature of symbioses in the gut. In contrast to cellulose, lignin degradation does not appear to be important in the gut of wood-feeding termites. Soil-feeding termites decompose humic substances in soil at least partly, but little is known about the decomposition. Fungus-growing termites are successful in the almost complete decomposition of lignocellulose in a sophisticated cooperation with basidiomycete fungi cultivated in their nest. A detailed understanding of efficient biorecycling systems, such as that for lignocellulose, and the symbioses that provide this efficiency will benefit applied microbiology and biotechnology.

Participation of bacterial biofilms in refractory and chronic periapical periodontitis

The aim of this study was to examine morphologically the participation of extraradicular biofilm in refractory periapical periodontitis. Six teeth and five extruded root filling gutta-percha points associated with refractory periapical periodontitis were investigated by scanning electron microscope. In nine of 11 samples examined, bacterial biofilms were seen at the extraradicular area. The gutta-percha surface was covered with glycocalyx-like structures, and filaments, long rods, and spirochete-shaped bacteria were predominant in the extraradicular sites. Planktonic cells, which were filaments and spirochete-shaped bacteria, emigrated from the glycocalyx structures in some spots. In the extracted teeth, biofilm consisting of both bacteria and glycocalyx-like structures were observed on the periapical root surfaces. Next to the residual periodontal ligament, a few filaments, rods, and fusiforms were attached on the healthy cementum surface. The present findings suggested that bacterial biofilms formed in the extraradicular areas were related to refractory periapical periodontitis.

Intestinal spirochetosis in eight pediatric patients from Southern Sweden

Intestinal spirochetes in humans have been recognized for more than a century, but it is still a matter of debate whether they are just commensal organisms or whether they cause colorectal disease. Most descriptions to date are of adult patients, while reports in the pediatric literature have been scarce. In a retrospective study we found eight children with intestinal spirochetosis. The findings, clinical as well as pathological, with light- and electron microscopy, are presented. In all patients, a 3 microm-thick layer of spirochetes was visualised on the luminal aspect of the epithelial cells covering the enterocytes and part of the gland openings. In five of the eight cases an inflammatory cell reaction was seen by light microscopy and in one patient a picture suggesting intracytoplasmatically located spirochetes was seen by electron microscopy. Despite partial or complete destruction of microvilli, spirochetes were still able to adhere to the enterocyte membranes. In three children there was a clear correlation between treatment and relief of symptoms. In four there was partial improvement and in one child no change in bowel-related symptoms. We believe that intestinal spirochetes may cause colorectal disease in children. Possible pathogenic mechanisms are discussed.

Zinc bacitracin enhances colonization by the intestinal spirochaete Brachyspira pilosicoli in experimentally infected layer hens

Brachyspira pilosicoli strain CPSp1 isolated from a chicken in a broiler breeder flock in Queensland was used to experimentally infect 40 individually caged 22-week-old laying hens. Another 10 birds were sham-inoculated with sterile broth. All chickens received a commercial layer diet, but 10 infected birds had 50 parts/10(6) zinc bacitracin (ZnB) incorporated in their food. Birds were kept for 7 weeks, and faecal moisture, egg numbers, egg weights and body weights were recorded weekly. B. pilosicoli was isolated from the faeces of only three of the 30 inoculated birds receiving the diet without ZnB, whereas seven of the 10 inoculated birds receiving ZnB in their diet were colonized. This difference in colonization rate was highly significant (P = < 0.001). Dietary ZnB at 50 parts/10(6) therefore predisposed to colonization by B. pilosicoli. Despite colonization, no significant production differences were found between the birds in the three groups.

Contamination of interdental brushes by periodontopathogens

Experimental studies have shown that intraoral transmission of bacteria can occur. Of course, the question arises as to how this transmission may happen. In this study, the contamination of interdental brushes by periodontopathogens is examined and compared to the microbial load of the periodontal pockets. In ten untreated chronic periodontitis patients, four interdental sites were professionally brushed with one interdental brush per patient. Subsequently, samples from the depths of the pockets (of the specific interdental sites) were obtained with paper-points. The interdental brush samples and the samples of the subgingival plaque, obtained by the pooled paper-points, were processed for dark-field microscopy examination as well as anaerobic culturing. The results showed that, although significant differences could be found between the brushes and paper-points with direct microscopy, the culturing did not uncover many differences. On the contrary, the detection frequencies of specific bacterial species were almost the same between the two. The total anaerobic colony-forming units (CFU), P. gingivalis, F. nucleatum, and E. corrodens found on the brushes showed a significant correlation with the subgingival plaque samples (P<0.005). These results suggest that, in untreated situations, interdental brushes are contaminated relatively easily by putative periodontopathogens in numbers comparable to their presence in periodontal pockets. This contamination could be a factor in the intraoral spread of bacteria.

Evaluation of tiamulin and lincomycin for the treatment of broiler breeders experimentally infected with the intestinal spirochaete Brachyspira pilosicoli

Brachyspira pilosicoli strain CPSp1 isolated from a chicken in a broiler breeder flock in Queensland was used to experimentally infect 30 individually caged 22-week-old Cobb 500 broiler breeder hens. Another 10 birds were sham-inoculated with sterile broth. All birds failed to become colonized. At 29 weeks of age, all birds were transferred to a diet containing 50 parts/10(6) zinc bacitracin (ZnB) and were re-challenged with the same B. pilosicoli strain at 32 weeks of age, weekly for 5 weeks. The majority of the inoculated birds then became colonized, confirming previous findings that ZnB can increase susceptibility to colonization with B. pilosicoli. The control group remained uninfected. Infected groups tended to have an increased faecal water content and faecal staining of eggshells. Ten birds were then treated by crop tube with 25 mg/kg body weight tiamulin for 5 days, and 10 birds with 20 mg/kg body weight lincomycin for 5 days. Both treatments removed the infection, while untreated birds remained infected. The results support previous observations that ZnB at 50 parts/10(6) in the diet increases the susceptibility of birds to B. pilosicoli infection, and demonstrated the usefulness of both tiamulin and lincomycin for treatment of infection with B. pilosicoli in adult birds.

Influence of in-feed zinc bacitracin and tiamulin treatment on experimental avian intestinal spirochaetosis caused by Brachyspira intermedia

Thirty individually caged layer hens were inoculated with Brachyspira intermedia, and 20 control birds remained unchallenged. Birds received a diet containing 100 parts/10(6) zinc bacitracin (ZnB), and were monitored for 10 weeks. B. intermedia was recovered sporadically from five of the inoculated birds, and there were no significant effects on body weight, faecal water or egg production. ZnB was presumed to be indirectly inhibiting spirochaete growth, and when removed from the diet, 18 of the 30 inoculated birds rapidly became culture positive. After 4 weeks, 10 of the 30 infected birds were treated with tiamulin at 25 mg/kg for 5 days, and 10 were returned to the diet containing ZnB. Birds receiving tiamulin became spirochaete negative and maintained their egg production, but re-infection occurred. The other 20 infected birds had a significant drop in egg production, but those receiving ZnB showed a reduced colonization by B. intermedia after 3 weeks.

Brachyspira (Serpulina) pilosicoli of human origin interfere with the growth of Clostridium perfringens alpha-toxin producer

Brachyspira (Serpulina) pilosicoli of human origin interfere with the growth of Clostridium perfringens alpha-toxin producer reducing the clostridial growth area and colonies number when bacteria were cultivated together in sheep blood agar plates. The growth inhibition of C. perfringens was only observed when B. (S.) pilosicoli grew 72-96 hours sooner than C. perfringens and after the inoculum of this latter the plates were anaerobically incubated for additional 48 hours. The phenomenon was observed at concentrations of B. (S.) pilosicoli ranging from 10(7) to 10(4) CFU/ml and at concentrations of C. perfringens ranging from 10(7) to 10(1) CFU/ml when the bacteria were 0-10 mm away from each other. When B. (S.) pilosicoli and C. perfringens were inoculated at the same time and when B. (S.) pilosicoli grew 24-48 hours sooner than C. perfringens, the clostridial growth inhibition was not appreciated and only a cooperative haemolysis was observed between the bacteria.

Brachyspira (Serpulina) pilosicoli of human origin interfere with the haemolytic activity and the growth of Staphylococcus aureus beta-toxin producer

Brachyspira (Serpulina) pilosicoli related to intestinal spirochaetosis were found to interfere in vitro with the haemolytic activity and the growth of Staphylococcus aureus beta-toxin producer. This interference was clearly appreciated because a reduction of the zone of the staphylococcal beta-toxin activity, the reduction and/or absence of cooperative haemolysis between bacteria, and the growth reduction of S. aureus were observed when B. (S.) pilosicoli were grown 72-96 hours sooner than S. aureus and after the inoculum of the latter the plates were anaerobically incubated for additional 48-72 hours. The phenomenon was more clearly observed when B. (S.) pilosicoli had a concentration of 8x10(6)-8x10(7) CFU/ml and S. aureus at a concentration ranging from 10(7) to 10(1) CFU/ml was inoculated at a distance from the streaks of B. (S.) pilosicoli ranging from 0-10 mm. When B. (S.) pilosicoli and S. aureus were inoculated at the same time and when B. (S.) pilosicoli grew 24-48 hours sooner than S. aureus only a cooperative haemolysis was observed.

Statistical modeling of tooth mobility after treating adult periodontitis

The healing process following periodontal surgery for advanced adult periodontitis is described. Of the various indicators, tooth mobility (TM) is considered, and its relation to surgical treatment and the time lapse from the flap surgery is quantitatively modeled by non-parametric regression. Mobility is measured by an electronic apparatus, which also automatically performs the modeling. A new statistical method for TM prediction is demonstrated, and its quality is estimated. We show that the quality at the first step of prediction is approximately 0.7. This indicates that the prediction method is able to model the effect of surgery on the healing process, although the random scattering of TM data recorded in the examined group is relatively large. The influence of periodontal surgery on TM, alone and in combination with systemic metronidazole, is quantitatively characterized in two groups of 12 patients each. In the test group, which received metronidazole, TM decreased significantly 1 week postoperatively, compared to the control group without the antibiotic. The gingival fluid flow rate (GFFR) and the percentage of spirochete morphotypes detected by darkfield microscopy exhibited a similar dependence. Significant differences in TM, GFFR and the percentage of spirochetes between the two groups were observed over a period of several weeks. Probing depths (PD) in both groups at 2 and 12 months after surgery did not reveal any category with pockets deeper than 4 mm. A gain of clinical attachment level of more than 2 mm (CAL) was observed at measurements of 16.7% and 10.6% on the test and control groups, respectively, 1 year after surgery.

The prevalence of human intestinal spirochetosis in Norway

The prevalence of human intestinal spirochetosis (HIS) was determined histologically in 402 subjects from South Norway (Kristiansand) who had undergone colorectal resections during the period June 1991-June 1996. The figures were compared with those from a previous mid-Norwegian study (Trondheim) comprising 1205 patients with large bowel resections as well as colonoscopic mucosal biopsies examined in 1990. The studies showed a prevalence of HIS of 2.5% in mid-Norway and 3.0% in South Norway, and in both regions there was a considerable male predominance of HIS (70% and 75%, respectively). Furthermore, HIS was more often diagnosed by the pathologists in South Norway (25%) than in mid-Norway (6.5%).

Weakly beta-haemolytic human intestinal spirochaetes antagonize the haemolytic activity of Clostridium perfringens alpha-toxin producer

The production of haemolytic antagonism between weakly beta-haemolytic human intestinal spirochaetes (wbetaHIS) related to human intestinal spirochaetosis and Clostridium perfringens alpha-toxin producer was investigated. A reduction of the clostridial haemolytic activity and a distortion of the haemolytic halo of clostridial alpha-toxin surrounded by a small zone of poorly cooperative haemolysis was clearly observed on the level of the spirochaetal growth area when 40 out of 41 wbetaHIS were cultivated in sheep blood agar plates together with Clostridium perfringens alpha-toxin producer. This phenomenon of haemolytic antagonism was observed only when wbetaHIS grew 72-96 hours sooner than C. perfringens and after the inoculum of the latter at a distance of 0 to 10 mm from wbetaHIS the plates were anaerobically incubated for an additional 48 hours and the bacteria were used at concentrations ranging from 10(7) to 10(4) CFU/ml. These results were also observed between C. perfringens and weakly beta-haemolytic intestinal spirochaetes related to animal intestinal spirochaetosis including avian strains and Brachyspira (Serpulina) pilosicoli of porcine origin.

Antibiotic selective markers and spirochete genetics

Until very recently, the pathogenic spirochetes have been refractory to genetic manipulation. This has been due, in part, to difficulties with in vitro growth and the genetic distance that spirochetes are from typical Gram-negative and Gram-positive organisms. Insertional mutagenesis and other genetic techniques are now possible in some of the pathogenic spirochetes such as Borrelia burgdorferi, Brachyspira (Serpulina) hyodysenteriae, Leptospira sp., and Treponema denticola. However, organisms such as Treponema pallidum, which cannot be grown in vitro, are still not amenable to genetic manipulation. These recent advances have paved the way for more detailed genetic studies of transcriptional regulation, protein function, protein localization, metabolic capabilities, motility, and pathogenic nature of this group of spirochetes. This review article will discuss the current repertoire of antibiotic markers that are useful for spirochetal genetic manipulation. Further advances in selectable markers and shuttle vectors will allow researchers to complete Koch's molecular hypothesis for various virulence genes of the pathogenic spirochetes and increase the overall understanding of these challenging bacteria.

Monitoring of activity dynamics of an anaerobic digester bacterial community using 16S rRNA polymerase chain reaction--single-strand conformation polymorphism analysis

The influence of parameter changes on the bacterial community of a laboratory-scale anaerobic digester fed with glucose was investigated using a culture-independent approach based on single-strand conformation polymorphism (SSCP) analysis of total 16S rDNA and 16S rRNA amplification products. With the digester operating at steady state, the 16S rDNA SSCP patterns of the bacterial community showed eight peaks, whereas the 16S rRNA patterns showed six peaks with a very prominent one corresponding to a Spirochaetes-related bacterium. An acidic shock at pH 6 caused an increase in the 16S rRNA level of two Clostridium-related bacteria. After a 1 week starvation period, the major bacteria present reverted to a basal 16S rRNA level proportional to their 16S rDNA level. Starvation revealed the presence of a previously undetected peak whose corresponding sequence was deeply branched into the low G+C Gram-positive bacteria phylum. Twenty-four hours after a spiked addition to the starved digester community of starch, glucose, lactate or sulphate, an upsurge in several new 16S rRNA-derived peaks was observed. Thus, the perturbation approach combined with 16S rRNA analysis revealed bacteria that had not been detected through 16S rDNA analysis.

Transcriptional regulation in spirochetes

Spirochetes belong to a widely diverse family of bacteria. Several species in this family can cause a variety of illnesses including syphilis and Lyme disease. Despite the fact that the complete genome sequence of two species, Borrelia burgdorferi and Treponema pallidum, have been deciphered, much remains to be understood about spirochetal gene regulation. In this review we focus on the environmental transitions that spirochetes undergo during their life cycles and the mechanisms of transcriptional regulation that might possibly mediate spirochetal adaptations to such changes.

Effect of an essential oil-containing dentifrice on dental plaque microbial composition

PURPOSE

To determine the effect of 6 months use of an essential oil-containing (EO) antiplaque/antigingivitis fluoride dentifrice on the balance of the oral microbial flora and on the emergence of resistant microbial forms by analysis of dental plaque and saliva.

MATERIALS AND METHODS

The dentifrice essential oils consisted of a fixed combination of thymol, menthol, methyl salicylate, and eucalyptol. An identical fluoride-containing dentifrice without the essential oils served as the control. A subgroup of 66 subjects from a clinical trial population of 321 was randomly selected for characterization of their dental plaque microflora. Saliva was also cultured to monitor for the emergence of opportunistic pathogens. Supragingival plaque and saliva were harvested at baseline, after which subjects received a dental prophylaxis. Subjects were sampled again after 3 and 6 months of product use prior to clinical examination. Plaque was characterized for microbial content by phase contrast microscopy for recognizable cellular morphotypes and by cultivation on nonselective and selective culture media. Determination of the minimum inhibitory concentrations of the test agent against selected Actinomyces and Veillonella isolated bacterial species was conducted at all time points to monitor for the potential development of bacterial resistance.

RESULTS

There were no statistically significant differences between the microbial flora obtained from subjects using the essential oil-containing dentifrice and the vehicle control for all parameters and time periods except for the percentage of spirochetes at 6 months and for percentage of "other" microorganisms at 3 months. The EO group exhibited a lower adjusted mean for both parameters. Additionally, there was no evidence of the development of bacterial resistance to the antimicrobial activity of the essential oils or the emergence of opportunistic pathogens.

Non-surgical periodontal treatment with and without adjunctive metronidazole in smokers and non-smokers

AIM

To determine whether adjunctive metronidazole therapy would compensate for the poorer treatment response to scaling and root planing reported in smokers.

METHOD

A single-blind, randomised clinical trial of 28 smokers and 56 non-smokers, stratified for periodontitis disease severity and randomly allocated to 3 treatment groups: (1) Scaling and root planing using an ultrasonic scaler with local anaesthesia (SRP), (2) SRP+ metronidazole tabs 200 mg tds for 7 days, (3) SRP + 2 subgingival applications of 25% metronidazole gel. Probing depths (PD) and attachment levels (AL) were recorded with a Florida probe at baseline, 2 months and 6 months post treatment by a single examiner who was unaware of the treatment modality. Results were analysed for all sites with baseline probing depths equal to or greater than Florida probe recordings of 4.6 mm using analysis of variance.

RESULTS

Reductions in probing depth at 6 months were significantly less (p < 0.001) in the smokers (mean 1.23 mm, 95% confidence intervals = 1.05 to 1.40 mm) than in the non-smokers (1.92, 1.75 to 2.09 mm). Attachment level gains were approximately 0.55 mm and there was no statistically significant difference between smokers and non-smokers. There were no differences in any clinical measure in response to the three treatment regimens at 2 or 6 months for either smokers or non-smokers. A reduction in the proportion of spirochaetes was observed at 6 months which was less in smokers than in non-smokers (p = 0.034). Multiple linear regression analysis on probing depth at 6 months demonstrated that smoking was a significant explanatory factor (p < 0.001) for poor treatment outcome, whilst the presence or absence of adjunctive metronidazole was not (p = 0.620).

CONCLUSION

This study confirms that smokers have a poorer treatment response to SRP, regardless of the application of either systemic or locally applied adjunctive metronidazole.

A new animal model for studying Lyme disease spirochetes in a mammalian host-adapted state

There is now substantial evidence that Borrelia burgdorferi, the Lyme disease spirochete, undergoes major alterations in antigenic composition as it cycles between its arthropod and mammalian hosts. In this report, we cultivated B. burgdorferi 297 within dialysis membrane chambers implanted into the peritoneal cavities of rats to induce antigenic changes similar to those which occur during mammalian infection. Chamber-grown spirochetes, which remained fully virulent, did not express either outer surface protein A or Lp6.6, lipoproteins known to be downregulated after mammalian infection. However, they did, express p21, a well characterized outer surface protein E homologue, which is selectively expressed during infection. SDS-PAGE, two-dimensional gel electrophoresis, and immunoblot analysis revealed that chamber-grown borreliae also expressed uncharacterized proteins not expressed by in vitro-cultivated spirochetes; reactivity with sera from mice chronically infected with B. burgdorferi 297 confirmed that many of these novel proteins are selectively expressed during experimental murine infection. Finally, we used differential display RT-PCR to identify transcripts of other differentially expressed B. burgdorferi genes. One gene (2.9-7lpB) identified with this technique belongs to a family of genes located on homologous 32- and 18-kb circular plasmids. The lipoprotein encoded by 2.9-7lpB was shown to be selectively expressed by chamber-grown spirochetes and by spirochetes during experimental infection. Cultivation of B. burgdorferi in rat peritoneal implants represents a novel system for studying Lyme disease spirochetes in a mammalian host-adapted state.

Cooperative haemolysis between weakly-beta haemolytic human intestinal spirochaetes and Clostridium perfringens

Interactions between human intestinal spirochaetes (HIS) related to intestinal spirochaetosis and intestinal pathogenic anaerobic bacteria were investigated by searching for the presence of cooperative haemolysis among 39 strains of weakly beta-haemolytic human intestinal spirochaetes and Clostridium perfringens alpha-toxin producers on plates carrying six different sheep blood agar media. An area of intense cooperative haemolysis (about 3-10 mm) was observed between all tested spirochaetal strains and C. perfringens where the clostridial alpha-toxin diffused toward the colonies of the spirochaetes overlapping part of their growth zone. The cooperative haemolysis was a potentiation of the haemolysis due to the single cultivation of human intestinal spirochaetes and C. perfringens and was observed after anaerobic incubation for 24-48 hours when both bacteria at a concentration range of 10(8)-10(3) CFU/ml were streaked at a distance of 3-10 mm to each other. A cooperative haemolysis was also observed between C. perfringens and weakly beta-haemolytic spirochaetes related to porcine and avian intestinal spirochaetosis and the spirochaete causing swine dysentery. The present study indicated that the damage produced in vitro by the clostridial alpha-toxin was enhanced only on the red blood cells which were in proximity to the HIS colonies causing the complete lysis of the erythrocytes. It is hence possible that the potentiation of the damage to red blood cells observed in vitro mimics an in vivo damage on the membranes of enterocytes to which HIS are attached when intestinal spirochaetosis occurs and when cytolysins similar to the alpha-toxin are available in the intestine of the host.

Microbiota associated with experimental peri-implantitis and periodontitis in adult Macaca mulatta monkeys

This study examines the microbiota associated with the progression of experimental peri-implantitis and periodontitis induced concurrently in partially edentulous adult monkeys. Root-form and plate-form implants with fixed prosthesis in place for at least 12 months and their corresponding opposite molar teeth were ligated for 6 months. The microbiota in plaque around these ligated dental implants and molars were studied at 0, 1, 2, 3, and 6 months post-ligation. Plaque samples were analyzed by dark-field microscopy and selective and non-selective culture. Putative periodontal pathogens were detected as a major component of the microbiota cultured from plaque samples obtained from experimental peri-implantitis sites. Overall, the types and relative proportions of putative periodontal pathogens in plaque associated with ligature-induced peri-implantitis and ligature-induced periodontitis were similar. Only levels of anaerobic Actinomyces and spirochetes were significantly different between both sites. Spirochete levels were significantly higher at peri-implantitis sites when compared with levels at periodontitis sites after 6 months, and spirochete levels increased significantly between 0 and 6 months post-ligation at implant sites. Levels of spirochetes correlated significantly with probing depth and bone loss at peri-implantitis sites. Overall, Actinomyces levels were higher at periodontitis sites. Porphyromonas species were not detected continuously as part of the peri-implantitis microbiota. In conclusion, this study finds that the microbiota associated with the progression of experimental peri-implantitis and periodontitis occurring concurrently in partially edentulous mouths are similar.

Effects of combined topical metronidazole and mechanical treatment on the subgingival flora in deep periodontal pockets in cuspids and bicuspids

The Effect on the subgingival microflora of a single topical administration of a 95% collagen and 5% metronidazole device in combination with debridement was investigated in 30 adult periodontitis patients in comparison with mechanical treatment alone. For each patient, plaque samples from test and control sites in cuspids and bicuspids were collected for culture and enumeration of total anaerobically cultivable bacteria (TA), black-pigmented anaerobes (BPA), and Actinobacillus actinomycetemcomitans (Aa). Spirochetes and fusiforms were quantified by direct microscopic examination after Giemsa staining. A decrease was observed for all parameters, and a significant difference in comparison with the control group was found for fusiforms. After treatment, a lower number of Aa positive sites were observed in the test group (13/25). These results show that a single application of topical metronidazole seems to be effective as adjunctive antimicrobial treatment in adult periodontitis.

Genetic and phenotypic characterization of intestinal spirochetes colonizing chickens and allocation of known pathogenic isolates to three distinct genetic groups

Infection with intestinal spirochetes has recently been recognized as a cause of lost production in the poultry industry. Little is known about these organisms, so a collection of 56 isolates originating from chickens in commercial flocks in Australia, the United States, The Netherlands, and the United Kingdom was examined. Strength of beta-hemolysis on blood agar, indole production, API ZYM enzyme profiles, and cellular morphology were determined, and multilocus enzyme electrophoresis was used to analyze the extent of genetic diversity among the isolates. The results were compared with those previously obtained for well-characterized porcine intestinal spirochetes. The chicken isolates were genetically heterogeneous. They were divided into 40 electrophoretic types distributed among six diverse genetic groups (groups b to g), with a mean genetic diversity of 0.587. Strains in two groups (groups d and e) may represent new species of Serpulina, and the groups contained only strains isolated from chickens. Three genetic groups contained isolates previously shown to be pathogenic for chickens. These corresponded to the proposed species "Serpulina intermedius," to an unnamed group (group e), and to Serpulina pilosicoli. Two of the chicken isolates (one "S. intermedius" and one S. pilosicoli isolate) were strongly beta-hemolytic, two (both "S. intermedius") had an intermediate level of beta-hemolysis, and the rest were weakly beta-hemolytic. Fourteen isolates of "S. intermedius" produced indole, as did one isolate from group d. Isolates identified as S. pilosicoli resembled porcine isolates of this species, having four to six periplasmic flagella inserted subterminally in a single row at each end of the cell, and had tapered cell ends. All other spirochetes were morphologically similar, having seven or more periplasmic flagella and blunt cell ends. The identification of three genetic groups containing pathogenic isolates provides an opportunity for more detailed epidemiologic studies with these pathogens and for the development of improved diagnostic tests.

The challenge of growing oral spirochaetes

Research in periodontal disease has shown the presence of oral spirochaetes repeatedly in subgingival plaque. There is uncertainty as to whether these spirochaetes are involved in the actual disease process; however, it has been shown that their presence is a definite marker for disease occurrence. An understanding of their role in periodontal disease requires further characterisation of these organisms. Diagnostic tests would be useful for the clinician and enable treatment for the patient to be planned. Studies on characterising the different treponemal species have been limited by difficulties in culturing these organisms. Moreover, there is a need to obtain pure cultures of these organisms and to identify them in order to associate particular species with disease and, ultimately, to make probes for their easy detection directly from dental plaque. This review examines the methods used, and reports our own experience, in obtaining pure cultures of oral spirochaetes. The techniques available and the problems that occur when identifying these organisms are also considered.

Evaluation of the in vitro activity of seven selected antimicrobial agents to be used for the isolation of human intestinal spirochaetes

This study aimed at making a comparative assessment of the growth of pure cultures of Human Intestinal Spirochaetes (HIS) in a control medium without antibiotics and in media including antibiotics (spectinomycin, rifampin, colistin, polymyxin B, amphotericin B, vancomycin, spiramycin) whose use had been indicated in the literature in connection with the isolation of HIS or animal intestinal spirochaetes. All the strains of HIS tested grew in media to which appropriate concentrations of those drugs had been added giving a final number of CFU/ml +/- 10 times the number of CFU/ml observed in the control medium. These results indicate that a selective medium to be used for the isolation of HIS may include appropriate concentrations of one or more of the following antibiotics: spectinomycin (100-1,000 micrograms/ml), rifampin (10-30 micrograms/ml), vancomycin (6.25 micrograms/ml), colistin (6.25 micrograms/ml), polymyxin B (5 micrograms/ml), spiramycin (1-10 micrograms/ml) and amphotericin B (0.05-35 micrograms/ml).

Comparative growth of pure cultures of human intestinal spirochaetes on six selective media

The growth of pure cultures of 24 human intestinal spirochaetes (HIS) was analysed comparatively in six selective media with antibiotics and in a control medium without antibiotics. The selective media SR and SP were the only two media among the six tested which allowed the growth of all the strains studied. These media contained spectinomycin (400 micrograms/ml) and rifampin (30 micrograms/ml) (SR), and spectinomycin (400 micrograms/ml) and polymyxin B (5 micrograms/ml) (SP), respectively. Moreover, most of the strains tested showed in these two media a number of CFU/ml equal to, or, for a few strains, not more than ten-fold lower than that observed in the control medium. The other four selective media tested were: SRVC (spectinomycin 200 micrograms/ml; rifampin 12.5 micrograms/ml; vancomycin 6.25 micrograms/ml; colistin 6.25 micrograms/ml), CSp (colistin 6.25 micrograms/ml; spiramycin 25 micrograms/ml), SRSp (spectinomycin 200 micrograms/ml; rifampin 12.5 micrograms/ml; spiramycin 25 micrograms/ml) and SRVCSp (spectinomycin 200 micrograms/ml; rifampin 12.5 micrograms/ml; vancomycin 6.25 micrograms/ml; colistin 6.25 micrograms/ml; spiramycin 25 micrograms/ml). The growth of most of the spirochaetes was strongly reduced in the media SRVC, CSp, SRSp and SRVCSp. Furthermore, several of the 24 HIS examined did not grow in the medium SRVC (3 spirochaetes, 11%), CSp (15 spirochaetes, 62%), SRSp (17 spirochaetes, 70%), SRVCSp (19 spirochaetes, 79%). The results reported in this paper indicate that the media SR and SP, of the six selective media tested, may profitably be used in the isolation of HIS as they did not significantly affect the growth of the HIS tested.

Intestinal spirochetosis and acquired immunodeficiency syndrome: ultrastructural studies of two cases

Two cases of intestinal spirochetosis (IS) with acquired immunodeficiency syndrome are reported. In case 1, a 48-year-old homosexual black man presented with a 1-month history of alternating watery diarrhea and constipation, which dissipated following the removal of two colonic hyperplastic polyps containing IS. In case 2, a 26-year-old homosexual black man presented with a 3-month history of persistent bloody diarrhea and was found to have chronic shigellosis and IS. Pathologic findings of IS were similar in both cases. Basophilic fringes typical of IS covered the surfacing colonic epithelium and consisted of dense growths of spirochetes adherent to and oriented perpendicular to the plasma membranes of the surfacing epithelium. The spirochetes measured 3 to 5 microns in length and 0.2 micron in width, contained four to eight axial fibrils, and closely resembled Brachyspira aalborgi ultrastructurally. These cases are notable because the histopathologic changes of IS were more extensive than generally described. There was involvement of both the right colon and rectum by IS in case 2, and in both cases there was extension of the IS down into the crypts of Lieberkühn, spirochetal invasion of the colonic mucosa, and a conspicuous inflammatory response by macrophages in the underlying lamina propria.

Nutrient and environmental growth factors for nine oral small-sized spirochete strains containing one endoflagellum from each cell end

The present investigation was carried out in order to obtain better information about the growth requirements of small-sized spirochetes containing one endoflagellum from each cell end. Nine strains of such spirochetes were isolated from subgingival plaque in patients suffering from advanced marginal periodontitis. The strains were maintained in fluid NOS medium with 0.07% Noble Agar. The following environmental factors were studied: Oxygen in the incubation atmosphere and the pH value of the medium. The following nutrient factors were studied: Rabbit serum, heart infusion and trypticase, bovine albumin, human globulin, long-chain fatty acids, volatile fatty acids, steroids, amino acids, carbohydrates, and Na-bicarbonate. Growth was normally determined after 3 days' incubation at 35 degrees C by counting numbers of spirochete cells in a Petroff-Hausser counting chamber. All strains tolerated 3% oxygen in the atmosphere and the pH-optimum was 7.5. Rabbit serum was found not to be an essential nutrient factor. Human globulin stimulated growth, while bovine albumin inhibited growth. Heart infusion and trypticase influenced growth moderately. Of the remaining nutrient factors the long-chain fatty acids inhibited growth and the volatile fatty acids did not affect growth, while certain carbohydrates, especially glucose, stimulated growth. Na-bicarbonate in low concentrations stimulated growth, while higher concentrations inhibited growth.

Characteristics of trypsin-like activity in subgingival plaque samples

Previous studies have demonstrated that the hydrolysis of the trypsin substrate N-benzoyl-DL-arginine-2-naphthylamide (BANA), by subgingival plaque obtained from a single site, correlates best with the numbers and proportions of spirochetes in plaque samples and may serve as an indicator of clinical disease. In this investigation, we determined whether the association between BANA hydrolysis and spirochetes could be obtained in pooled subgingival plaque samples. Concomitantly, the characteristics of this reaction in terms of substrate type and concentration, microbial numbers needed to give a positive reaction as assessed by microscopic counts, rapidity of hydrolysis, and the effect of pH and various additives on the plaque BANA hydrolytic activity have been studied in pooled plaque samples from patients who were periodontally healthy or diseased. In addition, it was determined whether BANA hydrolytic activity found in subgingival plaque reflected contributions from saliva and supragingival plaque. Results indicated that the assay can best be performed with 0.67 mmol/L BANA at pH 7.0. EDTA and CaCl2 gave a slight inhibition and DTT a slight enhancement of the BANA reaction by the pooled plaque suspensions. The majority of the reactions (85%) developed their full color after overnight incubation. BANA hydrolysis was not found in saliva and occurred with much greater frequency in subgingival plaque as opposed to supragingival plaque. Analysis of the data indicated that BANA hydrolysis by pooled subgingival plaque samples is a suitable test for the detection of spirochetes when two or three spirochetes per high microscopic field are present in the sample.

Early microbial colonization of permucosal implants in edentulous patients

In edentulous patients, the microbial colonization of permucosal implants of sintered hydroxyapatite was studied. Samples were taken from mucosa and dentures before insertion of implants and from supra- and subgingival sites two to 10 weeks after insertion. In total, five patients and 10 implants with clinically healthy peri-implant tissues were studied. The samples were investigated by dark-field microscopy and anaerobic culture. The supragingival plaque of the implants was dominated by Gram-positive cocci and rods, the subgingival plaque by Haemophilus spp. and Veillonella parvula. A group of bacteria was found specifically related to the implants: Actinomyces odontolyticus, Peptostreptococcus micros, Haemophilus actinomycetemcomitans, Eikenella corrodens, Capnocytophaga sputigena, and Leptotrichia buccalis. Black-pigmented Bacteroides was not found in any of the examined samples. Spirochetes were observed in denture plaque samples and in supragingival plaque of the implants. It is concluded that bacteria known as potential periodontal pathogens colonize the permucosal implants in the first weeks after insertion. The presence of these species seems to be dependent on the ecological factors provided by the artificial gingival crevice of the permucosal implants in the edentulous mouth.

Comparison of three dispersion procedures for quantitative recovery of cultivable species of subgingival spirochetes

Spirochetes are usually the predominant organisms observed microscopically in subgingival plaques removed from tooth sites associated with periodontitis, but these organisms are rarely isolated by cultural means, presumably because the media do not support their growth and/or because these fragile organisms are disrupted by the various procedures used to disperse plaque samples. In the present investigation, three dispersal procedures, sonification, mechanical mixing, and homogenization, were compared for their ability to permit the isolation of Treponema denticola, Treponema vincentii, Treponema socranskii, and Treponema pectinovorum from plaque samples on media that support the growth of these species. Plaque samples in which the spirochetes averaged 50% of the microscopic count were chosen. The highest viable recoveries of spirochetes were observed when the plaques were dispersed with a Tekmar homogenizer, and the lowest occurred with sonification. The highest recoveries averaged only about 1% of the total cultivable counts, indicating either that the sought-after species were minor members of the flora or that the dispersal procedures were still too harsh. A total of 91% of the isolates were T. denticola, 5% were T. socranskii, and 4% were a heretofore-undescribed species.

Microbiological and biochemical characterization of spirochetes isolated from the feces of homosexual males

Spirochetes were isolated from the feces of 11 homosexual males who had diarrhea. The anaerobic organisms were isolated from a selective medium that consisted of Trypticase soy agar supplemented with either 5% horse or human blood, 400 micrograms of spectinomycin per ml, and 5 micrograms of polymyxin B per ml. Nonselective media that permitted good growth of these fastidious organisms were developed, and selected biochemical tests were performed. The tests included carbohydrate utilization, detection of certain enzymes, and determination of volatile fatty-acid end products of metabolism. Two growth patterns were noted on solid media, a haze of growth and production of small colonies. Based on the results of biochemical tests, patterns of preformed enzymes, and volatile fatty-acid production, we believe that the 11 isolates represent a heterogeneous group of spirochetes. The data suggest that the human colon may harbor unique strains of cultivable spirochetes; additional study of the taxonomy of the organisms and assessment of their virulence for humans are needed.

Nutrient and environmental growth factors for eight small-sized oral spirochetes

The present investigation was carried out in order to obtain better information about the growth requirements for small-sized oral spirochetes containing two endoflagella from each cell-end. Eight strains of such spirochetes were isolated from subgingival plaque in patients suffering from advanced marginal periodontitis. The strains were maintained under anaerobic conditions in a fluid basal BHI medium with 15% inactivated rabbit serum, 0.07% Noble Agar and 5 micrograms/ml cocarboxylase. Firstly, the effect of trace amounts of oxygen in the atmosphere and pH in the medium on growth of the spirochete strains were examined. Secondly, the effect of different sera incorporated in the medium was examined, and thirdly, the effect of important growth factors in serum was studied by adding different serum components to the fluid basal medium instead of rabbit serum. Growth was always determined after 4 days' incubation at 35 degrees C, either by counting numbers of spirochete cells in a Petroff-Hauser counting chamber or by measuring the turbidity of the culture spectrophotometrically at 600 nm. There was no difference in growth by using an atmosphere containing 1% oxygen or an anaerobic atmosphere. It was found that serum (rabbit or human) was an essential growth component, and no single growth factor could replace rabbit serum. Only a long chain fatty acid mixture and an amino acid solution could, to a minor extent, stimulate growth compared to the basal medium without rabbit serum. Sodium bicarbonate inhibited growth of all strains. Finally, none of the strains fermented a series of low molecular weight carbohydrates, but all strains produced H2S and indole.

Isolation and characterization of the Lyme disease spirochete from the skin of patients with erythema chronicum migrans

The Lyme disease spirochete, which had previously been isolated with difficulty from human skin lesions of erythema chronicum migrans of Lyme disease, was grown from six of fourteen skin biopsies cultured in a newly modified Kelly's medium. In two instances the Lyme disease spirochetes that were grown were also seen in histopathologic sections. Organisms grew in clumps in liquid culture medium. All six isolates reacted with a monoclonal antibody to a 31,000-dalton outer membrane protein. Only three of six reacted to a monoclonal antibody to a 34,000-dalton outer membrane protein, suggesting that different subtypes of this organism may infect man. Penicillin, erythromycin, and minocycline were bactericidal agents to all six spirochetes. These in vitro findings may be helpful in determining specific antibiotic treatment of Lyme disease, which was previously based primarily on clinical observations.