Variation in the Gut Microbiota of Termites (Tsaitermes ampliceps) Against Different Diets

Termites are well recognized for their thriving on recalcitrant lignocellulosic diets through nutritional symbioses with gut-dwelling microbiota; however, the effects of diet changes on termite gut microbiota are poorly understood, especially for the lower termites. In this study, we employed high-throughput 454 pyrosequencing of 16S V1-V3 amplicons to compare gut microbiotas of Tsaitermes ampliceps fed with lignin-rich and lignin-poor cellulose diets after a 2-week-feeding period. As a result, the majority of bacterial taxa were shared across the treatments with different diets, but their relative abundances were modified. In particular, the relative abundance was reduced for Spirochaetes and it was increased for Proteobacteria and Bacteroides by feeding the lignin-poor diet. The evenness of gut microbiota exhibited a significant difference in response to the diet type (filter paper diets < corn stover diets < wood diets), while their richness was constant, which may be related to the lower recalcitrance of this biomass to degradation. These results have important implications for sampling and analysis strategies to probe the lignocellulose degradation features of termite gut microbiota and suggest that the dietary lignocellulose composition could cause shifting rapidly in the termite gut microbiota.

Alzheimer's Disease: Assessing the Role of Spirochetes, Biofilms, the Immune System, and Amyloid-β with Regard to Potential Treatment and Prevention

Alzheimer's disease (AD) is an infectious disease caused by spirochetes, and these spirochetes form biofilms, which attract the innate immune system. The innate immune system first responder, Toll-like receptor 2, generates both NF-κB and TNF-α which try to kill the spirochetes in the biofilm, but cannot penetrate the "slime". NF-κB is also responsible for the generation of amyloid-β (Aβ) which itself is anti-microbial. Aβ cannot penetrate the biofilm either, and its accumulation leads to destruction of the cerebral neurocircuitry. Treatment with penicillin (as in tertiary syphilis, the comparator to AD) is outlined; a biofilm dispersing agent may need to be added to the protocol.

Resurgence of persisting non-cultivable Borrelia burgdorferi following antibiotic treatment in mice

The agent of Lyme borreliosis, Borrelia burgdorferi, evades host immunity and establishes persistent infections in its varied mammalian hosts. This persistent biology may pose challenges to effective antibiotic treatment. Experimental studies in dogs, mice, and non-human primates have found persistence of B. burgdorferi DNA following treatment with a variety of antibiotics, but persisting spirochetes are non-cultivable. Persistence of B. burgdorferi DNA has been documented in humans following treatment, but the significance remains unknown. The present study utilized a ceftriaxone treatment regimen in the C3H mouse model that resulted in persistence of non-cultivable B. burgdorferi in order to determine their long-term fate, and to examine their effects on the host. Results confirmed previous studies, in which B. burgdorferi could not be cultured from tissues, but low copy numbers of B. burgdorferi flaB DNA were detectable in tissues at 2, 4 and 8 months after completion of treatment, and the rate of PCR-positive tissues appeared to progressively decline over time. However, there was resurgence of spirochete flaB DNA in multiple tissues at 12 months, with flaB DNA copy levels nearly equivalent to those found in saline-treated mice. Despite the continued non-cultivable state, RNA transcription of multiple B. burgdorferi genes was detected in host tissues, flaB DNA was acquired by xenodiagnostic ticks, and spirochetal forms could be visualized within ticks and mouse tissues by immunofluorescence and immunohistochemistry, respectively. A number of host cytokines were up- or down-regulated in tissues of both saline- and antibiotic-treated mice in the absence of histopathology, indicating host response to the presence of non-cultivable, despite the lack of inflammation in tissues.

The use of controlled release locally delivered 10% doxycycline hyclate gel as an adjunct to scaling and root planing in the treatment of chronic periodontitis: clinical and microbiological results

BACKGROUND

Local delivery of antimicrobial agents provides higher concentration of the drug in the periodontal site for longer periods than systemically delivered methods. In the present study an attempt is made to know the efficacy of controlled local drug delivery of doxycycline as an adjunctive treatment in the management of chronic periodontitis.

MATERIALS AND METHODS

A total of 12 patients, diagnosed as Chronic Periodontitis in the age of 25 to 55 years, were selected of both the sexes in this study. They were divided into Experimental group consisted of 30 sites who received complete scaling and root planing (SRP) followed by placement of Atridox gel and control group consisted of 30 sites who received only SRP. Clinical parameters were recorded at, baseline, days 30, 90 and 180. Parameters were plaque index, gingival index, gingival bleeding index and microbial analysis, probing pocket depth and Clinical attachment level (CAL). The microbiological analysis was done at baseline visit and at 90th day. Probing pocket depth and CAL were recorded only on day 0 and 180th day.

RESULTS

In 180 days study, both the groups exhibited a significant improvement in periodontal status. Significant gain in attachment level was observed in both the group. Between both the groups the clinical parameters in the experimental groups exhibited better results as compared to the control group. Both the groups exhibited significant reduction in the number of spirochetes.

CONCLUSION

Combination therapy of SRP and 10% DH gel demonstrated better results at all levels suggesting that this therapy can play a significant role as an adjunct to SRP in the management of chronic periodontitis.

Decreased susceptibility to doxycycline associated with a 16S rRNA gene mutation in Brachyspira hyodysenteriae

The objective of this study was to assess whether nucleotide substitutions in the 16S rDNA sequence of selected Brachyspira hyodysenteriae isolates could explain differences in doxycycline minimal inhibitory concentrations (MICs). The main part of the 16S rRNA gene was sequenced and compared for 19 isolates with different doxycycline MICs. A mutation in the 16S rRNA gene at the position corresponding to 1058 in Escherichia coli has been shown to cause tetracycline resistance in other bacteria. In the B. hyodysenteriae sequences a G1058C mutation was found for all isolates with increased doxycycline MICs whereas all susceptible isolates had the wild type sequence.

Anti–Tumor Necrosis Factor–α Treatment ActivatesBorrelia burgdorferiSpirochetes 4 Weeks after Ceftriaxone Treatment in C3H/He Mice

BACKGROUND

The effect of anti-tumor necrosis factor (TNF)-alpha treatment in Borrelia burgdorferi-infected and ceftriaxone-treated C3H/He mice was evaluated.

METHODS

Mice were infected with B. garinii A218 or B. burgdorferi sensu stricto N40. At 2 weeks of infection, one group was treated simultaneously with ceftriaxone and anti-TNF-alpha, whereas another received ceftriaxone at 2 weeks and anti-TNF-alpha 4 weeks later. One group received ceftriaxone treatment only. Infected and noninfected control groups were sham treated.

RESULTS

At 14 weeks of infection, B. burgdorferi could not be detected by cultivation or by polymerase chain reaction in tissue samples of any mouse treated with ceftriaxone only. However, spirochetes grew from the tissue samples of one-third of the mice treated with anti-TNF-alpha simultaneously or 4 weeks after ceftriaxone. These activated spirochetes showed ceftriaxone sensitivity rates, plasmid profiles, and virulence rates similar to those of bacteria used to infect the mice. All infected control mice and mice given anti-TNF-alpha only were culture positive.

CONCLUSIONS

This report shows that, after ceftriaxone treatment for 5 days, a portion of B. burgdorferi-infected mice still have live spirochetes in their body, which are activated by anti-TNF-alpha treatment.

Antimicrobial susceptibility testing of Brachyspira intermedia and Brachyspira pilosicoli isolates from Australian chickens

Susceptibilities of predominantly Australian isolates of the pathogenic intestinal spirochaetes Brachyspira intermedia (n = 25) and Brachyspira pilosicoli (n = 17) from chickens were tested in agar dilution against four concentrations each of the antimicrobials tiamulin, lincomycin, tylosin, metronidazole, tetracycline and ampicillin. Based on available minimum inhibitory concentration (MIC) breakpoint values for Brachyspira hyodysenteriae or other Gram-negative enteric veterinary pathogens, isolates of both species generally were susceptible to tiamulin, lincomycin, metronidazole and tetracycline. Although not classed as resistant, four isolates of B. intermedia had an elevated MIC range for tiamulin (1 to 4 mg/l), 11 isolates of B. intermedia and five of B. pilosicoli had an elevated MIC range for lincomycin (10 to 50 mg/l), one isolate of B. pilosicoli had an elevated MIC range for tetracycline (10 to 20 mg/l), and one isolate of B. intermedia and five of B. pilosicoli had an elevated MIC range for ampicillin (10 to 50 mg/l). A clear lack of susceptibility to tylosin (MIC > 4 mg/l) was seen in 11 isolates each of B. intermedia and B. pilosicoli, and to ampicillin (MIC > 32 mg/l) in two isolates of B. pilosicoli. These data suggest that some resistance to common antimicrobials exists among intestinal spirochetes obtained from laying hens and supports the need of MIC data for clinical isolates before any treatment is considered.

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.

Tiamulin resistance in porcine Brachyspira pilosicoli isolates

There are few studies on antimicrobial susceptibility of Brachyspira pilosicoli, therefore this study was performed to investigate the situation among isolates from pigs. The tiamulin and tylosin susceptibility was determined by broth dilution for 93 and 86 porcine B. pilosicoli isolates, respectively. The isolates came from clinical samples taken in Swedish pig herds during the years 2002 and 2003. The tylosin minimal inhibitory concentration (MIC) was >16 microg/ml for 50% (n=43) of the isolates tested. A tiamulin MIC >2 microg/ml was obtained for 14% (n=13) of the isolates and these were also tested against doxycycline, salinomycin, valnemulin, lincomycin and aivlosin. For these isolates the susceptibility to salinomycin and doxycycline was high but the MICs for aivlosin varied. The relationship between the 13 tiamulin resistant isolates was analyzed by pulsed-field gel electrophoresis (PFGE). Among the 13 isolates 10 different PFGE patterns were identified.

Effects of Griseoviridin and Viridogrisein against Swine Dysentery in Experimental Infection by Using Mice and Pigs

Griseoviridin, a known antibiotic produced by Streptomyces cacaoi subsp. cacaoi, was found to be active against Brachyspira hyodysenteriae--the bacterium causing swine dysentery. An in vitro synergism is observed when it is used in combination with viridogrisein--a simultaneously produced antibiotic. In mouse experiments, the effect of griseoviridin alone was less than that of lincomycin--a commercially available swine dysentery medication. However, a 1:1 mixture of griseoviridin and viridogrisein revealed a noticeable synergistic effect. In an evaluation using pigs artificially infected with B. hyodysenteriae, a large difference was not observed between the effect of griseoviridin alone and that in combination with viridogrisein. Nevertheless, griseoviridin alone exhibited a therapeutic effect superior to that of lincomycin.

Proposed mechanisms and preventative options of Jarisch-Herxheimer reactions

OBJECTIVE

To review the aetiologies and preventative methods associated with Jarisch-Herxheimer reactions (JHR).

DATA SOURCES

Ovid Medline (1966-June Week 1 2004) was utilized to assess biomedical literature; a review of the bibliographies of articles was also performed.

DATA SYNTHESIS

JHR often occurs with the treatment of spirochete infections. However, the mechanism by which the reaction takes place is not clearly defined.

CONCLUSION

Studies suggest with conflicting evidence that the JHR is caused by release of endotoxin-like material from the spirochete as well as cytokine elevation in the body. It appears the type of drug and the rate of spirochete clearance from the body have little effect on the incidence of the reaction. Many pretreatment options have been explored with limited efficacy with the exception of anti-tumour necrosis factor antibodies.

Mutations in ribosomal protein L3 and 23S ribosomal RNA at the peptidyl transferase centre are associated with reduced susceptibility to tiamulin in Brachyspira spp. isolates

The pleuromutilin antibiotic tiamulin binds to the ribosomal peptidyl transferase centre. Three groups of Brachyspira spp. isolates with reduced tiamulin susceptibility were analysed to define resistance mechanisms to the drug. Mutations were identified in genes encoding ribosomal protein L3 and 23S rRNA at positions proximal to the peptidyl transferase centre. In two groups of laboratory-selected mutants, mutations were found at nucleotide positions 2032, 2055, 2447, 2499, 2504 and 2572 of 23S rRNA (Escherichia coli numbering) and at amino acid positions 148 and 149 of ribosomal protein L3 (Brachyspira pilosicoli numbering). In a third group of clinical B. hyodysenteriae isolates, only a single mutation at amino acid 148 of ribosomal protein L3 was detected. Chemical footprinting experiments show a reduced binding of tiamulin to ribosomal subunits from mutants with decreased susceptibility to the drug. This reduction in drug binding is likely the resistance mechanism for these strains. Hence, the identified mutations located near the tiamulin binding site are predicted to be responsible for the resistance phenotype. The positions of the mutated residues relative to the bound drug advocate a model where the mutations affect tiamulin binding indirectly through perturbation of nucleotide U2504.

Antimicrobial resistance in Brachyspira pilosicoli with special reference to point mutations in the 23S rRNA gene associated with macrolide and lincosamide resistance

A point mutation in the 23S rRNA gene causes macrolide and lincosamide resistance in Brachyspira hyodysenteriae. The possible occurrence of a similar mutation in Brachyspira pilosicoli was studied and the MICs of six antimicrobial agents for Swedish field isolates of B. pilosicoli were determined. Of 10 isolates with high MICs of macrolide and lincosamide antibiotics, six had a mutation in nucleotide position 2058 or 2059 in the 23S rRNA gene as compared to the wild type of Escherichia coli, whereas none of 10 tylosin-susceptible isolates were mutated in this region. The mutations found in position 2058 were A --> T transversions, and in position 2059 either A --> G transitions or A --> C transversions. The MICs at which 90% of the B. pilosicoli field isolates were inhibited by tylosin, erythromycin, clindamycin, virginiamycin, tiamulin, and carbadox, were >256, >256, >4, 4, 2, and 0.125 microg/ml, respectively. In conclusion, point mutations in positions 2058 and 2059 of the 23S rRNA gene can cause macrolide and lincosamide resistance in B. pilosicoli. Macrolide resistance is widespread among Swedish field isolates of B. pilosicoli. Notably also a few isolates with elevated MICs of tiamulin were found.

Comparison of methods for antimicrobial susceptibility testing and MIC values for pleuromutilin drugs for Brachyspira hyodysenteriae isolated in Germany

In Germany treatment of swine dysentery is hampered by Brachyspira hyodysenteriae strains showing elevated MIC values to the few antibiotics licensed. Therefore, susceptibility testing of clinical isolates is an important service to the swine practitioner. This study compares the established agar dilution procedure for antimicrobial susceptibility testing of this fastidious anaerobe to the broth microdilution test newly developed [Anim. Health Res. 2 (2001) 59; Vet. Microbiol. 84 (2002) 123; J. Clin. Microbiol. 41 (2003) 2596]. A total of 221 isolates were examined twice with either test procedure using tiamulin and valnemulin as antibiotics. Both methods gave reproducible results, and the MIC values for the reference strains B. hyodysenteriae B204 and Staphylococcus aureus ATCC 29213 corresponded to previously published data. However, the results for individual strains differed significantly for both tests (P < 0.001) with MIC values being on average one dilution step lower in the broth dilution method. The 221 strains used for comparing test procedures were isolated between 1989 and 2001. An additional 102 strains isolated in 2002 were tested only with the broth dilution procedure. A significant rise in the average MIC value for both pleuromutilins could be demonstrated when comparing earlier isolates to those from 2000 to 2001 (P < 0.05), while in 2002 the average MIC significantly decreased when compared to the value in 2000 (P < 0.05). However, strains with MIC values for tiamulin as high as 8 microg/ml (broth dilution) could still be isolated.

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.

In vitro antimicrobial susceptibility of Brachyspira pilosicoli isolates from humans

The in vitro antimicrobial susceptibility of the anaerobic intestinal spirochete Brachyspira pilosicoli was investigated by an agar dilution method. Human (n = 123) and porcine (n = 16) isolates were susceptible to metronidazole, ceftriaxone, meropenem, tetracycline, moxifloxacin, and chloramphenicol; erythromycin and ciprofloxacin were not active. Resistance to amoxicillin and clindamycin varied. Amoxicillin susceptibility was restored by clavulanic acid.

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.

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.

Dietary enzyme and zinc bacitracin reduce colonisation of layer hens by the intestinal spirochaete Brachyspira intermedia

Brachyspira intermedia strain HB60 was used to experimentally infect 40 individually caged 22-week-old laying hens. Another 10 control birds were sham-inoculated with sterile broth. All chickens received an experimental layer diet based on wheat. The infected birds were randomly divided into four groups of 10, with the diet for each group containing either 50 ppm zinc bacitracin (ZnB), 100 ppm ZnB, 256 ppm of dietary enzyme (Avizyme), 1302), or no additive. Birds were kept for 6 weeks after infection, and faecal excretion of B. intermedia, faecal water content, egg numbers, egg weights and body weights were recorded weekly. Control birds remained uninfected throughout the experiment. B. intermedia was isolated significantly less frequently from the groups of experimentally infected birds receiving ZnB at 50 ppm or enzyme than from those receiving 100 ppm ZnB or no treatment. Infected birds had a transient increase in faecal water content in the week following challenge, but no other significant production differences were detected amongst the five groups of birds in subsequent weeks. It was not established how the ZnB at 50 ppm and the dietary enzyme reduced the ability of the spirochaete to colonise, but it may have been by bringing about changes in the intestinal microflora and/or the intestinal microenvironment.

Brachyspira aalborgi infection in four Australian children

AIM

The clinical presentation of four children and adolescents (two males and two females with a mean age of 12.4 years; range 9-16 years) with colorectal spirochetosis is discussed.

RESULTS

Symptoms included persistent diarrhea (n = 2), rectal bleeding (n = 1) and abdominal pain (n = 2). In all patients, colorectal spirochetosis was an unanticipated finding on colonic histology, and the presence of spirochetes was confirmed by the use of electron microscopy. Spirochetes were identified as Brachyspira aalborgi by using PCR amplification of the bacterial 16S rRNA and nicotinamide adenine dinucleotide oxidase sequences in all four patients. No other enteric pathogens were found.

CONCLUSIONS

Although all patients appeared to respond to antibiotic treatment, the clinical significance of B. aalborgi as a human pathogen requires further investigation.

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.

Long-term treatment with subantimicrobial dose doxycycline exerts no antibacterial effect on the subgingival microflora associated with adult periodontitis

BACKGROUND

The purpose of this study was to determine whether treatment with subantimicrobial dose doxycycline (SDD), 20 mg bid, exerted an antimicrobial effect on the microflora associated with adult periodontitis.

METHODS

Following the approval of the protocol and informed consent forms by the respective IRBs at the University of Florida and West Virginia University, 76 subjects with adult periodontitis were entered and randomly assigned to receive SDD or placebo. A split-mouth design was utilized, with each subject receiving subgingival scaling and root planing (SRP) in two quadrants immediately following baseline data collection, while the remaining two quadrants were left unscaled (non-SRP). Microbial samples were collected prior to treatment, after 3, 6, and 9 months of treatment, and after 3 months of no treatment. The samples were examined by microscopy and by enumeration on selective and non-selective media.

RESULTS

All treatments resulted in statistically significant decreases in the proportions of spirochetes and motile rods (P <0.05) and in an increase in the proportion of coccoid forms (P <0.0001) relative to baseline. No between-treatment differences were detected between the SDD and placebo treatments in either the SRP or non-SRP design, with the exception of the small and large spirochetal groups. The spirochetal proportions present in the SDD group were significantly lower (P<0.05) than the paired placebo group during the 9-month treatment and was preceded by a significant decrease (P<0.01) in the proportion of microbiologic sample sites that bled on probing. No between- treatment differences were detected in any of the other microbial parameters.

CONCLUSION

The microbial differences observed were attributed to the anticollagenase and anti-inflammatory properties of SDD and not to an antimicrobial effect.

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.

[Clinical and bacteriologic response to irrigation with a chlorhexidine solution in the treatment of periodontal pockets]

Most of parodontal diseases have a bacterial aetiology. Their episodic and asynchronic evolution differs from site to site. The "in situs" antimicrobian used in the parodontal bags reduces the systemic administration. Various antibiotics or antiseptics slow liberation systems were experimented. Two patients suffering from advanced parodontitis were treated after radicular scraping by subgingival irrigation with a syringe filled with chlorhexidine. Each patient presented at last four parodontal bags more or less six millimetres (6 mm) deep. The following clinical parameters were noted: Patch index, bleeding index, bag depth. A bacteriological analysis was realized at the beginning and of the treatment. Controls were made at D60. Results showed a significant improvement of clinical parameters. It seems that the chlorhexidine irrigation improves the parodontal treatment efficiency.

Clinical and microbiological effects of initial periodontal therapy in conjunction with amoxicillin and clavulanic acid in patients with adult periodontitis. A randomised double-blind, placebo-controlled study

The aim of the present study was to investigate the clinical and microbiological effects of initial periodontal therapy in conjunction with systemic amoxicillin plus clavulanic acid in adult periodontitis patients using a double-blind, parallel-group, and placebo-controlled protocol. 21 patients with a clinical diagnosis of generalised adult periodontitis were recruited. Clinical measurements and microbiological assessments were carried out at baseline, 3, and 12 months post-treatment. Approximately 6 weeks after initial periodontal treatment (3-6 h), patients were randomly assigned to receive coded study medication of 500 mg amoxicillin plus 125 mg clavulanic acid (Augmentin) or placebo, every 8 h for 10 days. Patients returned for follow-up visits 3, 6, 9, and 12 months after completion of the medication. The mean plaque index (PI) at baseline was 1.1 for placebo group and 0.9 for the test group. At 3 months, the PI had dropped to 0.3 in both groups, and was maintained during the rest of the study. The changes in bleeding on probing (BOP) and gingival index (GI) in the course of the study were similar in both groups. The mean whole mouth probing pocket depth (PPD) in the placebo group was 3.8 mm at baseline and 3.9 mm in the test group. A mean reduction of 1.0 mm in the placebo group and 0.9 mm in the test group was observed during the first 3 months. No further reduction in PPD was noticed during the study period in either group. There was no statistically significant difference in the PPD reduction between the 2 groups. The change in clinical attachment level (CAL) from baseline to 3 months amounted to 0.5 mm in both groups. Between 3 and 12 months, the CAL changed in neither group. In both groups, treatment resulted in a decrease in the number of spirochetes and motile rods in positive patients, but no significant differences between either group were noted in any of the dark field microscopy observations. At baseline, 1 patient in the placebo group and 2 patients in the test group were culture positive for Actinobacillus actinomycetemcomitans (Aa). After therapy, Aa was not detectable in the placebo group and 1 patient remained positive in the test group. In the placebo group, the number of patients positive for Porphyromonas gingivalis (Pg) decreased from 7 to 2 after therapy. In the test group, the 4 patients positive for Pg at baseline remained positive after therapy. In both groups, all subjects were positive for Prevotella intermedia (Pi) and Fusobacterium nucleatum (Fn) at baseline. At 12 months, all subjects had detectable subgingival Fn. 9 out of the 11 placebo and 8 of the 10 test patients remained positive for Pi. There were no differences in detection frequency of Peptostreptococcus micros (Pm) and Bacteroides forsythus (Bf) in both groups between baseline, 3, and 12 months post-treatment. The findings demonstrated that, in comparison to placebo, systemic amoxicillin plus clavulanic acid provided no additional clinical and microbiological effects in the treatment of adult periodontitis patients.

One stage full- versus partial-mouth disinfection in the treatment of chronic adult or generalized early-onset periodontitis. II. Long-term impact on microbial load

BACKGROUND

Recent studies showed the clinical benefits of a one stage full-mouth disinfection, when compared to the worldwide standard treatment strategy of consecutive root planings per quadrant without proper disinfection of the remaining intraoral niches. The purpose of this study was to investigate the microbiological benefits of such a one stage full-mouth disinfection with special attention to all intraoral niches for periodontopathogens and to evaluate the perception by the patients of the new treatment strategy.

METHODS

Sixteen patients with early-onset periodontitis and 24 patients with severe adult periodontitis were randomly assigned to test and control groups. The control group was scaled and root planed, per quadrant, at 2-week intervals and given oral hygiene instructions. The test group received the one stage full-mouth disinfection treatment. At baseline and after 1, 2, 4, and 8 months, microbiological samples were taken from all niches (tongue, mucosa, saliva, and pooled samples from single- and multi-rooted teeth). The samples were cultured on selective and non-selective media. Patient perception of the treatment was evaluated using a questionnaire.

RESULTS

In comparison to the standard therapy, the one stage full-mouth disinfection resulted in significant additional microbial improvements. The test group showed larger reductions in the proportions of spirochetes and motile organisms in the subgingival flora, and more significant reductions in the density of key pathogens, with even the eradication of P. gingivalis. The beneficial effects in the other niches were primarily restricted to the number of colony-forming units/ml of black-pigmented bacteria, especially on the mucosa and in the saliva and to a lesser extent on the tongue. Both treatments were well tolerated by the patients and the overall severity rating for both therapies was comparable, although 4 quadrants were treated within 24 hours in the test group versus only 1 in the control group. The full-mouth disinfection approach resulted more frequently in a slight increase of body temperature, especially after the second day.

CONCLUSIONS

These findings support the benefit of a one stage full-mouth disinfection in the treatment of patients with either chronic adult or early-onset periodontitis.

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.

The efficacy of a single pocket irrigation on subgingival microbial vitality

The object of this study was to monitor the proportion of vital bacteria (microbial vitality: VF in %) present in subgingival dental plaque following one single subgingival irrigation with saline (S), chlorhexidine (CHX) or povidone iodine (I2), but without any subgingival instrumentation. Its effect on the main composition of the microflora was also assessed. Seventeen patients with adult periodontitis took part in this investigation. In each patient four initially untreated pockets (pocket depth 5-11 mm) associated with bleeding were selected for the standardised pocket irrigation and plaque sampling at baseline (0 h) and after the following 1 h, 24 h, 7 days and 31 days. The subgingival irrigation was only performed once (0 h). One pocket per quadrant was irrigated using 0.9% prereduced S, 0.2% CHX or 0.05% I2 (Iso-Betadine Buccale). The remaining untreated pocket without any irrigation served as an additional control (C). Using an acrylic splint as a guide, paperpoints were inserted into the pocket precisely at the same site to collect subgingival plaque. The bleeding on sampling (BOS) was thereafter noted. The proportions of bacterial morphotypes were examined by darkfield microscopy. VF was evaluated using a vital fluorescence staining. The undisturbed subgingival dental plaque was composed of 86% (median value) vital bacteria. The sampling procedure alone and the saline irrigation led to a decrease in the number of spirochetes but had no influence on the vitality of the flora. Large variations in VF could be observed in the short-term (1 h, 24 h) irrigation effect of CHX and I2. The reduction of VF was still significant after 7 days (VF(CHX) 30-80%, VF(I2) 35-80%) but persisted up to 31 days only after I2 irrigation (VF(I2) 12-90%). The findings indicated that all single subgingival irrigations resulted in a temporary change of the subgingival microflora while povidone iodine produced the longest lasting antimicrobial effect. Any clinical advantage of this situation should be further investigated.

Clinical and microbiological effects of minocycline-loaded microcapsules in adult periodontitis

Clinical and microbiological effects of subgingival delivery of 10% minocycline-loaded (MC), bioabsorbable microcapsules were examined in 15 adult periodontitis patients. Patients received oral hygiene instruction 2 weeks prior to the study. At baseline (day 0) all teeth received supragingival scaling (SC); 2 quadrants received no further treatment and 1 quadrant received subgingival scaling and root planning (SRP). In the fourth quadrant, the tooth with the deepest probing sites (at least 1 site > or = 5 mm) was treated with minocycline microcapsules. The sites were evaluated at baseline and weeks 1, 2, 4, and 6. Clinical indices included bleeding on probing (BOP), probing depths (PD), and attachment loss (AL). Microbiological evaluations included percent morphotypes by phase-contrast microscopy; cultivable anaerobic, aerobic, and black-pigmented Bacteroides (BPB); and percent Porphyromonas gingivalis, Prevotella intermedia, Eikenella corrodens, and Actinomyces viscosus by indirect immunofluorescence. In the SC + MC group, BOP, PD, and AL were significantly reduced from baseline for weeks 1 to 6. BOP in the SC + MC group was significantly reduced compared to the SRP group from weeks 2 to 6. In the SC + MC group the percent of spirochetes and motile rods decreased and the percent of cocci increased after 1 week. The increased cocci and decreased motile rods were statistically greater at weeks 4 and 6 in the SC + MC group compared to the SRP group. This study demonstrates that local subgingival delivery of 10% minocycline-loaded microcapsules as an adjunct to scaling results in reduction in the percent sites bleeding on probing greater than scaling and root planning alone and induces a microbial response more favorable for periodontal health than scaling and root planing.

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).

Azithromycin in the treatment of periodontal disease. Effect on microbial flora

Azithromycin is an azalide antibiotic with excellent in vitro activity against a wide variety of oral bacteria. It has a long half-life, good tissue penetration and is preferentially taken up by phagocytes. We investigated the microbiological efficacy of azithromycin as an adjunct to the non-surgical treatment of adult chronic periodontitis; its clinical efficacy is dealt with in a separate paper. 46 patients were treated in a double-blind placebo controlled trial. Microbiological assessment of the same periodontal pocket (initially > 6 mm) was made at weeks 0, 2, 3, 6, 10 and 22. Either azithromycin 500 mg 1 x daily for 3 days or placebo was given at week 2. Particular attention was paid to the numbers of black pigmented anaerobes and spirochaetes present since these are the most commonly implicated pathogens in periodontal disease. Pigmented anaerobes were significantly reduced at weeks 3 and 6 in patients who received azithromycin compared to placebo and remained lower, although not significantly so, throughout the study. Counts of spirochaetes were significantly reduced throughout the study in patients who received azithromycin compared to placebo. Our microbiological study suggests that azithromycin may be useful as an adjunct in the treatment of periodontal disease.

Microbiological response to mechanical treatment in combination with adjunctive therapy. A review of the literature

The recognition of the microbial origin and the specificity of periodontal infections has resulted in the development of several adjunctive therapies (antibiotics and/or antiseptics) to scaling and root planing in the treatment of chronic adult periodontitis. This article aims to review the "additional" effect of a subgingival irrigation with chlorhexidine, or a local or systemic application of tetracycline or metronidazole, performed in combination with a single course of scaling and root planing in patients with chronic adult periodontitis. All treatment modalities are compared with scaling and root planing, based on their impact on: the probing depth (PD); total number of colony forming units per ml (CFU/ml); the proportions and/or the detection-frequency of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia; and/or on the percentages of cocci, spirochetes, motile, and other micro-organisms on dark field microscopy examination. All treatment modalities, including scaling and root planing without additional chemical therapy, resulted in significant reductions in the probing depth and the proportions of periodontopathogens, at least during the first 8 weeks post-therapy. However in comparison to a single course of scaling and root planing, the supplementary effect of adjunctive therapies seems to be limited. In general, only the irrigation with chlorhexidine 2%, the local application of minocycline, and the systemic use of metronidazole (in case of large proportions of spirochetes) or doxycycline (in case of large proportions of A. actinomycetemcomitans) seem to result in a prolonged supplementary effect when compared to scaling and root planing. Therefore, the use of antibiotics on a routine basis, especially in a systemic way, in the treatment of chronic adult periodontitis, can no longer be advocated, considering the increasing danger for the development of microbial resistance.

Full- versus partial-mouth disinfection in the treatment of periodontal infections. A pilot study: long-term microbiological observations

A standard periodontal treatment consists of 4 to 6 scalings and rootplanings at a 1- to 2-week interval, which allows reinfection of a previously disinfected area before completion of the treatment. The present pilot study aims to examine the microbiological long-term effects of a full-mouth disinfection. 10 patients with advanced chronic periodontitis were randomly allocated to a test and control group. The patients from the control group received scaling and rootplaning and oral hygiene instructions at a 2-week interval. The full-mouth disinfection (test group) consisted of a full-mouth scaling and rootplaning in 2 visits within 24 h in combination with: tongue brushing with 1% chlorhexidine gel for 1 min, mouth rinsing with 0.2% chlorhexidine solution for 2 min and subgingival irrigation of all pockets (3x in 10 min) with 1% chlorhexidine gel. The patients of the test group were instructed to rinse 2x daily with 0.2% chlorhexidine. Plaque samples were taken at baseline and after 1, 2, 4 and 8 months. Differential phase-contrast microscopy showed a significantly larger reduction of spirochetes and motile organisms in the test group up to month 2 for the single-rooted and up to month 8 for the multi-rooted teeth. Furthermore, the culture data supported the effectiveness of the new treatment strategy. In both groups, the number of anaerobic CFU decreased 1 log around single- and 0.5 log around multi-rooted teeth. The number of anaerobic CFU remained low in the test group, in contrast to the control group. At 1 month, the test group harboured a significantly (p<0.01) lower proportion of pathogenic organisms, but this difference disappeared with time. Moreover, the test sites showed a significantly higher (p<0.02) increase in the proportion of beneficial micro-organisms up to 4 months. These findings suggest that a full-mouth disinfection leads to a significant microbiological improvement up to 2 months, which could be consolidated, although not significant, for the next 6 months.

The effect of cyclosporin-A on the oral microflora at gingival sulcus of the ferret

The effect of cyclosporin-A (CyA) on the dentogingival flora of ferrets with healthy and experimentally induced periodontal breakdown was studied. Five animals were given 10 mg/kg/d CyA. At the start of the experiments (day 0), ligatures were placed around 4 teeth in the right upper and lower jaws; corresponding contralateral teeth on the left side served as control. On days 0 and 28 (end of the experiment), microbiological samples were collected from the gingival sulcus of the experimental and the control teeth and from closely located gingival mucosa membrane. The samples were subjected to viable counts and to darkfield microscopic analyses. On day 0, facultative anaerobic rods, mainly Pasteurella spp, Alcaligenes spp, Corynebacterium spp. and Rothia spp dominated in the viable counts. No anaerobic bacteria were detected in the viable counts. On day 28 spirochetes increased in the experimental gingival sulcus samples and anaerobic bacteria appeared in most of the samples and constituted 40-60% of the total cultivable flora; Fusobacterium necrophorum and Eubacterium spp. predominated in the samples from the experimental sites. The results of the present study were compared with those of our previous investigation of ferrets not medicated with cyclosporin but also subject to experimental ligature periodontitis. Eubacterium spp. were absent in the animals not treated with cyclosporin, while this species was frequently present in the immunosuppressed ferrets. The results indicate that the presence of the large numbers of gram negative rods and of anaerobic bacteria may have enhanced the inflammatory process and further provoked the gingival overgrowth observed.

Response to intracrevicular controlled delivery of 25% tetracycline from poly(lactide/glycolide) film strips in SPT patients

Controlled local delivery of antibiotics has been shown to reduce periodontopathic micro-organisms with minimal side-effects. Clinical studies in our laboratory have shown that 25% tetracycline HCl delivered from poly(D,L-lactide/glycolide) film strips (25 TTC-PLGA) released therapeutic concentrations of tetracycline for 10 days. The present pilot study compared the intracrevicular delivery of 25% tetracycline HCl incorporated in these biodegradable film strips to scaling and root planing (SRP) in 10 adult periodontitis patients, who in spite of therapy and regular supportive periodontal treatment (SPT), continued to possess 5 bleeding periodontal pockets at least 5 mm deep. Sites were randomly selected to receive the following treatments: (1) 25 TTC-PLGA, (2) control strips without TTC (PLGA), (3) SRP, and (4) untreated control. Film-strip retention was augmented with a suture/cement technique, followed by strip removal after 2 weeks. Clinical parameters and subgingival bacterial morphotypes (darkfield analysis) were evaluated over time (0, 2.4, 8, 12, 26 weeks). Results indicated that, compared to baseline, 25 TTC-PLGA film strips caused significant (p < or = 0.01): (1) probing depth reduction for 26 weeks, (2) a clinical attachment level gain for 12 weeks, (3) lower %s of spirochetes for 4 weeks and motile rods for 8 weeks (p < or = 0.05), and (4) an accompanying increase in cocci for 4 weeks. In the scaled and root planed sites, probing depth was the only finding that demonstrated a significant change from baseline (p < or = 0.01). Controls and PLGA showed isolated reductions in probing depth and % of motile organisms. From these findings, applications of intracrevicular 25 TTC-PLGA, when compared to scaling and root planing, appears to have an enhanced antibacterial effect and a similar clinical effect in SPT patients. The results of this study indicate further investigation of 25 TTC-PLGA film strips should be undertaken using more subjects and sophisticated microbiological and clinical measurements.

Use of an oral antiseptic bioadhesive tablet in dogs

V3703 (Stomadhex) is a tablet with bioadhesive properties enabling it to remain in place for several hours after it has been placed on the oral mucosa. It continuously releases chlorhexidine and niacinamide. In a study conducted in 15 dogs, the tablets were well tolerated by the animals. The product significantly reduced (p < 0.05): dental plaque; quantitative periodontopathogen and total anaerobic bacterial counts; spirochetes; and halitosis when used daily over a 14 day period. Gingivitis was also reduced, though not significantly (p = 0.07). Stomadhex treatment can provide a carry-over effect following dental scaling by reducing oral microflora and retarding the reappearance of dental plaque.

Evaluation of the efficacy of a redox agent in the treatment of chronic periodontitis

A redox dye, methylene blue, was compared with subgingival root surface debridement and sterile water in the treatment of adult periodontitis. Plaque and gingival indices, bleeding on probing, and microbiological samples were obtained at baseline, and at 1, 4, 8 and 12 weeks following treatment. All subjects had matched pockets in each of the 4 quadrants, of 5 mm or more. One treatment consisted of 0.1% methylene blue gel irrigated professionally at 0, 1 and 4 weeks, and by subjects at days in between up to 4 weeks, at chosen sites within a randomly selected quadrant (split-mouth design). A 2nd treatment was sterile water irrigation as above. A 3rd quadrant received subgingival debridement, and sites in the 4th received methylene blue incorporated into a slow-release device of a biodegradable collagen alginate vicryl composite. All sites showed improvements in clinical and microbiological parameters. However, no statistically significant differences between treatment types were found for clinical measurements. Although plaque index tended to increase after week 1, gingival index was reduced, as was the papilla bleeding index. Probing depth reductions were approximately 1.2 mm for all treatments. Microbiological variables showed an increase in cocci and a decrease in motile organisms for all groups, the latter reaching statistical significance for subgingival debridement. The reductions in spirochaetes were significant for subgingival debridement and methylene blue by slow-release. Culture demonstrated an increase in the aerobe:anaerobe ratio for all groups, which was statistically significant initially (weeks 1 and 4) for subgingival debridement. Methylene blue was also effective statistically in improving this ratio, both by irrigation and slow-release (week 4). Methylene blue also significantly reduced the numbers of black-pigmented anaerobes during the trial period, both by irrigation and slow-release, which sterile water and subgingival debridement failed to do. No serious adverse experiences were seen, however, significantly greater morbidity was associated with subgingival debridement. These results clearly demonstrate that in altering the microflora to one that is more compatible with periodontal health, methylene blue treatment is comparable, or even better, than the currently standard treatment of subgingival debridement, and is better tolerated.

Metronidazole in periodontitis (IV). The effect of patient compliance on treatment parameters

Patient compliance with the unsupervised usage of prescription medication can be poor. In the treatment of periodontal infections with systemic antimicrobial agents, in situations where the efficacy of the antimicrobial agent is being evaluated, non-compliance could underestimate the true efficacy of the agent. Metronidazole is an agent with reported success in the treatment of anaerobic periodontal infections. Metronidazole is particularly effective in vitro against spirochetes, and this efficacy was investigated as a means of measuring patient compliance with metronidazole usage. Patients who had high proportions of spirochetes, i.e., > 20%, in plaques removed from diseased periodontal sites, were given metronidazole (500 mg bid) under supervision. In all individuals who received the metronidazole, there was a significant and rapid decline and/or disappearance of spirochetes from the plaque during the time interval that metronidazole was detectable in the saliva. This observed decline in spirochetes was then used to determine which patients had been compliant in a double-blind clinical trial involving the unsupervised usage of metronidazole. Only 10 of 18 patients (56%) were considered compliant in their usage of metronidazole. These 10 patients experienced a significantly greater benefit from the metronidazole than did the 8 patients who were considered noncompliant, i.e., a reduction of surgical needs of 8.3 teeth per compliant patient versus 3.6 teeth per non-compliant patient. A test for the hydrolysis of the synthetic peptide (BANA) was also able to identify most non-compliant patients. Clinical trials involving the unsupervised usage of systemic medication need to take into account patient non-compliance.

Clinical effects of simultaneous ultrasonic scaling and subgingival irrigation with chlorhexidine. Mediating influence of periodontal probing depth

The clinical and microbial effects of a single episode of simultaneous ultrasonic scaling and subgingival irrigation with chlorhexidine (CHX) were studied as a function of clinical probing depth in patients with adult periodontitis. 60 patients were randomly assigned to receive subgingival irrigation under cavitation with either sterile water or 0.12% CHX delivered through the tip of an ultrasonically activated scaler as part of initial periodontal therapy in a double-blind study design. 3 periodontal sites were randomly selected for examination from each patient on the basis of clinical probing depth, with 1 site being selected within each of the following ranges: 1-3 mm, 4-6 mm, and 7-9 mm. Pretreatment and post-treatment (days 14 and 28) clinical assessments included a plaque index (PI), gingival index (GI), and clinical probing depth (CPD). Subgingival specimens also were collected from 1-3 mm and 4-6 mm sites on a random subset of patients (15 per group). Plaque counts of spirochetes and motile organisms were made by darkfield microscopy. Significant reductions in PI, GI, and CPD were observed among all sites within both treatment groups at 14 and 28 days post-treatment. CHX irrigation resulted in a significantly greater reduction in CPD than did water among sites initially probing 4-6 mm at both 14 and 28 days post-treatment (25% versus 13% and 31% versus 18%, respectively). Spirochete counts were modestly but nonsignificantly reduced at 14 days post-treatment among sites 4-6 mm within both treatment groups. These results suggest that subgingival irrigation with CHX during ultrasonic scaling provides differential clinical benefits that are site-dependent.

Minocycline slow-release formulation effect on subgingival bacteria

The purpose of this study was to determine the microbiological efficacy of an adjunctive minocycline periodontal formulation delivered subgingivally. Subjects were systemically healthy but exhibited severe periodontitis; i.e., probing depths greater than 6 mm. The two study groups included individuals who received minocycline or a placebo periodontal formulation after root planing. Subgingival plaque samples were obtained at baseline; prior to treatment; and at 1, 3, and 6 months. Plaque was evaluated by darkfield microscopy and further analyzed for total dark-pigmented Bacteroides species, P. intermedia, P. gingivalis and Streptococcus, Actinomyces, Eikenella, Actinobacillus, Capnocytophaga, and Fusobacterium species using cultivable flora techniques. In addition, plaque was evaluated for yeast on a selective agar medium. When compared to the placebo, the minocycline group had significantly lower proportions of spirochetes at 1 and 3 months and lower proportions of motile rods at 3 months. Furthermore, when compared to the placebo group, the minocycline patients had lower mean proportions of dark-pigmented Bacteroides spp. and P. intermedia at 1 and 3 months as well as lower proportions of E. corrodens at 1 month. The minocycline group had significant decreases in proportions of spirochetes at 1 and 3 months, motile rods at 1 and 3 months, and increases in cocci at 1, 3, and 6 months when compared to baseline. In the placebo group, root planing was also effective at decreasing spirochetes at 1, 3, and 6 months, but with significant differences seen only at 3 and 6 months. However, the degree of reduction in spirochete proportions was greater in the minocycline group when compared with the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)

Metronidazole in periodontitis: reduced need for surgery

A considerable amount of circumstantial evidence indicates that most forms of periodontitis are due to the presence or dominance of a finite number of bacterial species in the subgingival plaque. Almost all of the putative pathogens are anaerobic species, indicating that most forms of periodontitis could be diagnosed as anaerobic infections. In this double-blind investigation, patients with elevated proportions or levels of spirochetes in 2 or more plaque samples, i.e., 60% spirochetes, were randomly assigned to receive either metronidazole, 250 mg 3 x a day for 1 week, or placebo (positive-control) after the completion of all debridement procedures. When the patients were re-examined 4 to 6 weeks later, the patients in the metronidazole group (n = 15) exhibited a highly significant (p less than 0.01) reduction in probing depth and apparent gain in attachment levels relative to the patients (n = 18) in the positive-control group about those teeth that initially had probing depths of 4 to 6 mm. This pattern was also observed about teeth that initially had probing depths greater than or equal to 7 mm. This reduction in probing depths and apparent gain in attachment was associated with a significant reduction in the need for periodontal surgery in the metronidazole-treated patients (difference 8.4 teeth per patient) compared to the positive-control patients (2.6 teeth per patient). These clinical improvements in the metronidazole group were associated with significantly lower proportions of spirochetes, selenomonads, motile rods, and P. intermedius, and a significantly higher proportion of cocci in the plaques. These findings indicate that systemic metronidazole, when given after all the root surface debridement is completed, leads to additional treatment benefits, including a reduced need for surgery, beyond that which can be achieved by debridement alone.

Effect of systemic doxycycline administration on the subgingival microbial flora: a dark-field microscopy study

The effect of systemically administered doxycycline hydrochloride on subgingival microbial plaque morphotypes was evaluated using dark-field microscopy. After 1 week of drug administration, while the percentage of coccoid bacteria showed a significant increase, the percentages of spirochetes, motile rods and non-motile rods tended to decrease. Since spirochetes and/or motile rods are considered to be associated with the pathogenesis of periodontal disease, the significant decrease in the proportions of these bacteria are considered to be important. Therefore, it is suggested that doxycycline may be beneficial for the treatment of periodontal disease as an adjunct to traditional therapeutic methods.

Evaluation of stannous fluoride and chlorhexidine sprays on plaque and gingivitis in handicapped children

The objective of this study was to evaluate the effect of twice-daily oral sprays of 2 ml chlorhexidine (0.2%) and 2 ml stannous fluoride (0.2%) as the sole oral hygiene measure on plaque and gingivitis in handicapped children. 52 institutionalized mentally handicapped individuals (aged 10-26 years) were divided into 4 groups to participate in a 9-week, double-blind, randomized clinically controlled trial, which included a cross-over. For the first 3 weeks, groups 3 and 2 had their mouths sprayed with chlorhexidine and stannous fluoride, respectively. Following a 3-week wash-out interval, groups 1 and 4 were sprayed with chlorhexidine and stannous fluoride, respectively. The alternate groups received a placebo, water. Plaque (PI) and gingival indices (GI) were recorded. Subgingival plaque samples were collected and counts of spirochaetes, motile rods and cocci were taken using darkfield microscopy. By the 9th week of trial, the PI and GI were reduced by 48% and 52% for the stannous fluoride group. In the chlorhexidine group, reductions of 75% (PI) and 78% (GI) were achieved. Pair-wise comparisons of placebo, stannous fluoride and chlorhexidine using the U-test of Mann-Whitney revealed significant (p less than 0.05) differences for both PI and GI scores in the placebo/stannous fluoride and placebo/chlorhexidine pair by the 9th week of the trial. In the stannous fluoride/chlorhexidine pair, only the PI was significantly reduced for those on chlorhexidine. Coccoid cells were more dominant at sites with low PI and GI scores (stannous fluoride and chlorhexidine groups), while spirochaetes and motile rods were more frequent at sites with high PI and GI scores (placebo group).

Therapeutic effects of combined treatment using tetracycline-immobilized collagen film and root planing in periodontal furcation pockets

46 upper and lower molars with furcation grade II involvement were selected from 16 patients with periodontal disease. The teeth were randomly allocated to the following groups according to treatment; (1) 4 consecutive administrations of tetracycline-immobilized cross-linked collagen film (TC film) at intervals of 1 week (TC group); (2) 1 root planing treatment (RP group); (3) combination treatment (TC + RP group); (4) no treatment (control group). The therapeutic effects of each treatment were compared both clinically and microbiologically. Records of plaque index, gingival index, bleeding on probing, probing depth, probing attachment level and microscopic counts were obtained at 0, 4, 6 and 8 weeks. The results showed marked decreases in probing depth and density of micro-organisms in both the RP and TC + RP groups. In particular, the TC + RP group was characterized by a decreased rate of bleeding on pocket probing and an increased probing attachment gain. The above findings demonstrated that root planning is effective in the treatment of furcation involvement and that the effects are enhanced by the local administration of TC films.