Isolation of Capnocytophaga species with a new selective medium

Bergeyella zoohelcum isolated from oral cavities of therapy dogs

Bergeyella zoohelcum causes rare but severe human clinical diseases, which mostly arise from animal bites. Notably, Bergeyella infections can also occur in older people after prolonged exposure to dogs or cats without biting. We detected B. zoohelcum in oral cavities of therapy dogs in close contact with older people residing in nursing homes. Twenty-two bacterial isolates were identified as B. zoohelcum by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing. Our results showed that MALDI-TOF MS is an effective tool for rapid identification of rarely isolated, difficult-to-identify microorganisms, such as B. zoohelcum, derived from not only human clinical samples but also animal samples. To our knowledge, this is the first report on detection of B. zoohelcum from therapy dogs. We have provided information on dog-assisted therapy to improve the relationship between humans and animals in ageing societies, particularly for preventive healthcare of older people living in nursing care facilities.

Capnocytophaga keratitis in dogs: clinical, histopathologic, and microbiologic features of seven cases

OBJECTIVE

To describe the clinical, microbiologic, and histopathologic features of Capnocytophaga keratitis in dogs.

ANIMALS STUDIED

Seven dogs with naturally acquired Capnocytophaga keratitis.

PROCEDURES

Medical records of dogs with a clinical diagnosis of keratitis and corneal cultures positive for Capnocytophaga spp. were reviewed. Dog signalment, medical history, clinical findings, and diagnostic assay results were recorded.

RESULTS

Breeds included Boston terrier (n = 3 dogs), Rat terrier (n = 2), and single cases of mixed breed and Pug. All dogs examined had expansive corneal ulceration involving the majority of the corneal surface. Marked corneal infiltrates, keratomalacia, and hypopyon were present. Progression of corneal disease was rapid with extensive dissolution of the corneal stroma. Corneal lesions progressed to catastrophic perforations within 24 h of the initial examination in three dogs, requiring enucleation. One globe was enucleated after failure to resolve with long-term medical therapy. Globes and vision were retained in three dogs following aggressive medical therapy (two dogs) or 360° conjunctival graft surgery (one dog). Capnocytophaga cynodegmi, Capnocytophaga canimorsus, or unspeciated Capnocytophaga spp. were cultured from corneal samples of all dogs. Long, thin, gram-negative rods were present during cytological evaluation of the cornea in some dogs. Histopathologic evaluation of enucleated globes revealed severe and diffuse neutrophilic and collagenolytic keratitis.

CONCLUSIONS

Capnocytophaga keratitis is a severe, rapidly progressive corneal infection in dogs that is associated with diffuse corneal involvement, extensive keratomalacia, and a relatively poor prognosis. Clinical features of canine Capnocytophaga keratitis are similar to human cases of this infection.

Antibiotic content of selective culture media for isolation of Capnocytophaga species from oral polymicrobial samples

In oral microbiome, because of the abundance of commensal competitive flora, selective media with antibiotics are necessary for the recovery of fastidious Capnocytophaga species. The performances of six culture media (blood agar, chocolate blood agar, VCAT medium, CAPE medium, bacitracin chocolate blood agar and VK medium) were compared with literature data concerning five other media (FAA, LB, TSBV, CapR and TBBP media). To understand variable growth on selective media, the MICs of each antimicrobial agent contained in this different media (colistin, kanamycin, trimethoprim, trimethoprim-sulfamethoxazole, vancomycin, aztreonam and bacitracin) were determined for all Capnocytophaga species. Overall, VCAT medium (Columbia, 10% cooked horse blood, polyvitaminic supplement, 3·75 mg l(-1) of colistin, 1·5 mg l(-1) of trimethoprim, 1 mg l(-1) of vancomycin and 0·5 mg l(-1) of amphotericin B, Oxoid, France) was the more efficient selective medium, with regard to the detection of Capnocytophaga species from oral samples (P < 0·001) and the elimination of commensal clinical species (P < 0·001). The demonstrated superiority of VCAT medium, related to its antibiotic content, made its use indispensable for the optimal isolation of Capnocytophaga species from polymicrobial samples.

SIGNIFICANCE AND IMPACT OF THE STUDY

Isolation of Capnocytophaga species is important for the proper diagnosis and treatment of the systemic infections they cause and for epidemiological studies of periodontal flora. We showed that in pure culture, a simple blood agar allowed the growth of all Capnocytophaga species. Nonetheless, in oral samples, because of the abundance of commensal competitive flora, selective media with antibiotics are necessary for the recovery of Capnocytophaga species. The demonstrated superiority of VCAT medium made its use essential for the optimal detection of this bacterial genus. This work showed that extreme caution should be exercised when reporting the isolation of Capnocytophaga species from oral polymicrobial samples, because the culture medium is a determining factor.

Prevalence of 6 putative periodontal pathogens in subgingival plaque samples from Romanian adult periodontitis patients

The aim of the present study was to determine by standard cultivation procedures the detection frequencies of Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans, Bacteroides forsythus, and Capnocytophaga species as well as various enteric rods in subgingival plaque samples form Romanian adult periodontitis patients. DNA probe analysis (Affirm DP Microbial Identification Test) was also used, parallel to cultivation, to identify P. gingivalis, A. actinomycetemcomitans, and B. forsythus, in deep (> or = 6 mm) and intermediate (4-5 mm) pockets in some of the subjects investigated. Paper points were used to sample 86 deep pockets in 36 patients and 27 intermediate pockets in 9 of the 36 patients. The chi 2 test was used to test for significance of differences between results obtained by cultivation and DNA analysis in both intermediate and deep pockets. P. gingivalis was recovered in a high percentage of the patients (75.8%) and sites (63.6%) examined, followed by P. intermedia, F. nucleatum, and A. actinomycetemcomitans, respectively. Capnocytophaga species were present in almost all subjects. Enteric rods were recovered in 61.1% of the patients and 55.8% of the sites. Except for this high prevalence of enteric rods, the present group of patients had the periodontal species monitored in %s similar to those commonly perceived in the West. The Affirm DP Test and cultivation showed poor correlation in detecting P. gingivalis, A. actinomycetemcomitans, and B. forsythus. The cultivation prevalence of P. gingivalis and P. intermedia in deep pockets was similar to their prevalence in intermediate ones. Overall, the prevalence of the periodontal pathogens investigated in the present Romanian periodontitis patients is similar to what has been revealed in matching Norwegian and other Western periodontitis patient populations. The high prevalence of enteric rods in the Romanian patients may have been an artifact resulting from prolonged transport of the samples in VMGA III.

Dental treatment of Papillon-Lefèvre syndrome: 15-year follow-up

A 9-year-old girl was initially treated for the periodontal component of Papillon-Lefèvre syndrome by extraction of all patient's erupted teeth, after unsuccessful clinical treatment with two different antibiotics. Follow-up dental records at age 24 showed the patient to have generalized gingivitis and poor oral hygiene; however, no additional teeth were lost or mobile. Radiographically, the alveolar crests, lamina dura, and periodontal ligament spaces appeared normal for a subject with missing teeth. Initially, the patient had depressed polymorphonuclear leukocyte (PMN) chemotaxis and adherence, as well as evidence of periodontal infection with Actinobacillus actinomycetemcomitans, (A.a.). The 6 and 15-year follow-ups showed normal PMN function and no detectable A.a. The improvement of the patient's PMN function was coincident with lack of detection of certain periodontopathic bacteria. If the PMN dysfunction of PLS is secondary to the infection, the reasons for the initiation of the disease still need to be clarified.

Comparative detection frequency of 6 putative periodontal pathogens in Sudanese and Norwegian adult periodontitis patients

Twenty-five sudanese and 18 norwegian adult periodontitis patients were selected to participate in this study. The purpose was to compare cultivation results of Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, and Capnocytophaga species as well as various enteric rods in both populations. In addition, DNA probe analysis was used to identify P. gingivalis, P. intermedia, A. actinomycetemcomitans, F. nucleatum, and Bacteroides forsythus in the Sudanese patients and results were compared with those obtained by cultivation. The paper point technique was used to sample 99 sites in the Sudanese group (4 paper points/site) and 119 sites in the Norwegian patients (3 paper points/site). In the Sudanese subjects, the fourth paper point was used for the DNA probe analysis. The chi-square test and the Wilcoxon signed rank test were used to test for statistically significant differences between Sudanese and Norwegian cultivation results as well as between cultivation and DNA results in the Sudanese group. Cultivation results indicated that the Sudanese subjects had significantly lower prevalence of P. gingivalis, P. intermedia, and F. nucleatum (P < 0.01), significantly higher prevalence of Capnocytophaga species (P < 0.05), and similar prevalence of A. actinomycetemcomitans. Almost all Sudanese subjects tested positive for various enteric rods, while none of the Norwegians did so. The extent to which unrestricted use of antibiotics and transport media influenced the levels of enteric species is not known, however.(ABSTRACT TRUNCATED AT 250 WORDS)

Localized prepubertal periodontitis in a 5-year-old child: investigations and clinical observations over a 3-year period

A 5-year-old boy presented with persistent generalized gingival inflammation. Clinical and radiographic examination supplemented by immunological and microbiological investigation led to a diagnosis of localized prepubertal periodontitis. The child was subsequently monitored for 3 years and despite treatment there was continued bone loss related to his primary teeth. This case highlights the need for liaison between specialists in paediatric dentistry, periodontology, immunology and microbiology in order to diagnose prepubertal periodontitis and to establish a rational basis for treatment to prevent progression to juvenile periodontitis.

The effects of Acacia arabica gum on the in vitro growth and protease activities of periodontopathic bacteria

The antibacterial activity of acacia gum was assessed using fresh isolates and reference strains of Actinobacillus actinomycetemcomitans, Capnocytophaga spp., Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola. A fine aqueous suspension of gum was produced by sonication and then a soluble fraction isolated by centrifugation and membrane filtration. These preparations were incorporated into columbia agar at doubling concentrations. Growth of P. gingivalis and P. intermedia cultures on the agar was inhibited by whole gum sonicate at concentrations of 0.5-1.0% w/v. Both species showed reduced susceptibility when horse blood was present in the agar. The gum soluble fraction did not inhibit growth of any bacterial culture. The effect of acacia on bacterial proteases was examined with cell sonicates from log phase broth cultures. Enzyme activities were determined by fluorimetric assay with various synthetic peptide substrates. Most protease activities reduced in the presence of 0.5% w/v gum sonicate, with the trypsin-like activities of P. gingivalis and P. intermedia proving most sensitive. The gum soluble fraction was nearly always less inhibitory than the sonicate. The action of acacia gum against suspected periodontal pathogens and their enzymes suggests that it may be of clinical value.

Improved metabolic control, clinical periodontal status and subgingival microbiology in insulin-dependent diabetes mellitus. A prospective study

The effect of improved metabolic control on the clinical periodontal condition and the subgingival microflora of diseased and healthy periodontal pockets in 6 ambulatory insulin-dependent diabetes mellitus (IDDM) patients was prospectively studied. Duplicate measurements with a time-interval of 3 days were made every 4 moths for assessment of the metabolic status, the clinical periodontal condition and the subgingival microflora. During the study, patients maintained personal oral hygiene measures as they usually did before the study. Neither supplementary dental prophylaxis nor oral hygiene measures were applied during the investigation. Long-term metabolic control (HbAlc) improved significantly with intensive conventional insulin treatment. Gingival redness decreased significantly whereas gingival swelling showed a not significant trend to decrease. It is suggested that microvascular changes associated with improved metabolic control in diabetes mellitus may mediate the observed change in gingival redness. No effect could be demonstrated for probing pocket depth, probing attachment level, bleeding on probing and the plaque index. Statistical analysis of the effect of improved metabolic control on the subgingival microflora revealed that only the % of streptococci increased significantly in diseased periodontal pockets. In general, no significant changes were found in either healthy or diseased pockets with regard to the bacterial flora associated with periodontal disease. The results of the present study indicate that improved metabolic control in IDDM patients may have no potential impetus for an improved clinical periodontal condition nor on the subgingival bacterial flora. It is concluded that the periodontal condition in IDDM patients may only ameliorate when local oral hygiene measures are applied.

Periodontal condition and microbiology of healthy and diseased periodontal pockets in type 1 diabetes mellitus patients

On the basis of glycosylated hemoglobin (HbA1c) values, 22 type 1 (insulin-dependent) diabetic adults were grouped into patients with near normal (HbA1c less than or equal to 7.7%) and poor (HbA1c greater than or equal to 9.9%) metabolic control. A total of 44 subgingival sites were examined for Actinobacillus actinomycetemcomitans, black-pigmented Bacteroides species and Capnocytophaga species. No significant difference could be demonstrated between patients in the 2 test groups with regard to periodontal condition. Neither age of diabetic patients nor duration of diabetes mellitus influenced the periodontal parameters. In both test groups, pocket depth of 4 mm or more (greater than or equal to 4 mm) was found to be significantly associated with increased swelling, bleeding after probing and amount of marginal plaque. Proportionally high %s of cultivable A. actinomycetemcomitans (mean 4.3%; range 2.8-5.8%), Bacteroides gingivalis (33.2% and 34.6%) and Bacteroides intermedius (mean 4.2%; range 0.001-13.5%) were isolated from diseased periodontal pockets. In diabetic patients with poor metabolic control, B. intermedius was isolated from diseased periodontal pockets with a mean % of 7.2%, range 0.3-12.5%. Independent of the degree of metabolic control, low %s of Capnocytophaga species were isolated from diseased and healthy periodontal pockets, mean 0.9% (range 0.003-3.9%) and mean 1.4% (range 0.04-4.9%), respectively. It was concluded from this study that metabolic control seems to have no direct effect on the periodontium. Furthermore, the rôle of Capnocytophaga species in the pathogenesis of infectious periodontal disease in type 1 diabetic patients seems to be overestimated.(ABSTRACT TRUNCATED AT 250 WORDS)

Capnocytophaga

Capnocytophaga has been found to cause disease in the normal and the immunocompromised patient. Most often this organism is an opportunist that is difficult to isolate but easy to identify and a unique reminder that uncommon infection may respond to common antibiotics.

Capnocytophaga species: a cause of amniotic fluid infection and preterm labour

Subclinical amniotic fluid infection and subsequent preterm labour may occur with intact membranes. We report two cases of subclinical amniotic fluid infection with intact membranes presenting in preterm labour. Capnocytophaga species, fastidious Gram-negative bacilli normally found in oral flora, were isolated in pure culture from amniotic fluid obtained by transabdominal amniocentesis. The distinctive microbiological features and spectrum of infections associated with Capnocytophaga species, and the importance of recognition of subclinical amniotic fluid infection as a cause of preterm labour, are discussed.

In vitro susceptibility of Capnocytophaga species to 29 antimicrobial agents

A hemoglobin-supplemented medium composed of Columbia agar base supplemented with 1% hemoglobin and 1% Polyvitex was used to investigate the in vitro activity of 29 antimicrobial agents against Capnocytophaga species. Clindamycin was the most active agent, with all strains being inhibited by 0.06 microgram/ml or less. Amoxicillin-clavulanic acid and imipenem were the most active among the beta-lactam antibiotics (MIC for 90% of strains tested [MIC90], 0.50 microgram/ml); other very active drugs were BMY 28142, cefpirome, cefotaxime, ceftazidime, and ceftriaxone (MIC90, 0.06 to 0.50 micrograms/ml), although at least one strain showed resistance to each of these antibiotics (MIC, greater than or equal to 16 micrograms/ml). Ciprofloxacin was the most active among the quinolones, with all strains being inhibited by 0.50 microgram/ml. The MICs of the other four drugs ranged from 0.12 to 4 micrograms/ml. Ampicillin, penicillin G, ticarcillin, aztreonam, and temocillin were moderately active (MIC90, 1 to 8 micrograms/ml; MIC range, less than or equal to 0.03 to greater than 128 micrograms/ml). All strains were uniformly resistant to the aminoglycosides, polymyxin B, vancomycin, trimethoprim, and amphotericin B. Three strains produced beta-lactamase. No significant difference was found between the susceptibility of strains isolated from various sources or patients.