Molecular identification of black-pigmented bacteria from subgingival samples of cats suffering from periodontal disease.

OBJECTIVES: To characterise the black-pigmented bacterial species found in the subgingival samples of cats with periodontal disease using molecular-based microbiological techniques. METHODS: Sixty-five subgingival samples obtained from 50 cats with periodontal disease were analysed by polymerase chain reaction amplified ribosomal DNA restriction analysis and cloning and sequencing of the 16S rRNA genes. RESULTS: Among the 65 subgingival samples, eight phylogenetic profiles were obtained, of which the most prevalent species were: Porphyromonas gulae (40%), P. gingivalis/P. gulae (36 · 9%), P. gulae/Porphyromonas sp. UQD 406 (9 · 2%), Odoribacter denticanis (6 · 2%), P. gulae/Porphyromonas sp. UQD 348 (1 · 5%) and P. circumdentaria (1 · 5%). When compared with the species resulting from biochemical diagnosis, the identification of P. gulae was congruent in 70% of the cases, while colonies identified as P. intermedia-like corresponded in 80% of cases to P. gulae. CLINICAL SIGNIFICANCE: The use of molecular-based microbiological diagnostic techniques resulted in a predominance of Porphyromonas spp. in the subgingival plaque of cats suffering from periodontal disease. Further characterisation of these bacteria identified P. gulae, O. denticanis and P. circumdentaria. The more frequently detected phylogenetic profiles corresponded to P. gingivalis and P. gulae.

Isolation and identification of Porphyromonas spp. and other putative pathogens from cats with periodontal disease.

The purpose of this study was to evaluate the subgingival microbiota and determine the most prevalent periodontal pathogens implicated in feline periodontal disease and to correlate these findings with the clinical periodontal status. Subgingival microbiological samples were taken under sedation from 50 cats with clinical signs of periodontal disease. Pooled paper point samples from 4 selected subgingival sites were cultured on blood agar and on Dentaid-1 medium. Suspected pathogens were identified, subcultured, and preserved. The association between the microbiological findings and the clinical status was studied using correlation coefficients (CC). In addition, cats were stratified in subgroups according to presence of putative pathogens, and comparisons were carried out using unpaired t-test. Three bacterial species were frequently detected including Porphyromonas gulae (86%), Porphyromonas circumdentaria (70%) and Fusobacterium nucleatum (90%). The mean proportion of total flora was high for P. gulae (32.54%), moderate for P. circundentaria (8.82%), and low for F. nucleatum (3.96%). Among the clinical variables, tooth mobility was correlated (CC > 0.50, p < 0.001) with recession, pocket depth, attachment level, gingival index, and calculus index (CC = 0.29, p = 0.04) as well as with total bacterial counts (CC = 0.38, p = 0.006). Cats with more than 10% of P. gulae showed significantly more mobility (p = 0.014) and recession (p = 0.038), and a tendency for deeper probing pocket depths (p = 0.084) and attachment loss (p = 0.087). The results from this cross-sectional study confirmed that P. gulae is the most relevant pathogen in periodontal disease in cats.

Comparison of two sampling methods for microbiological evaluation of periodontal disease in cats.

BACKGROUND: Periodontal disease in cats is highly prevalent, and its aetiology is associated to bacteria located in the subgingival microbiota, being Porphyromonas sp. the most prevalent genus. The conventional technique to sample the subgingival microbiota is the use of cotton swabs over the mucosa and teeth; however the use of subgingival paper points could improve the bacterial recovery. AIM: The objective was to compare two microbial sampling approaches for the evaluation of the periodontal disease-associated microflora in cats. METHODS: The study was designed as a pilot study. Ten cats were clinically evaluated and sampled under sedation. Subgingival pooled samples were collected from four sites. In parallel, samples were obtained with a cotton swab, by striking over the gingival margin and surface of the upper right canine. Samples were cultured on blood agar (aerobic and anaerobic incubation), Dentaid-1 (for Aggregatibacter actinomycetemcomitans and enterics), and a specific medium for Bartonella henselae. RESULTS: For total anaerobic counts, paper point samples (6.59 ± 0.5) demonstrated significantly higher counts (p=0.03) than cotton swab samples (5.54 ± 1.1). Moreover, the use of paper points increased the frequency detection of most pathogens thus reducing false negatives for Porphyromonas gulae (100% with paper points samples and 80% with cotton swab samples). CONCLUSIONS: Significant higher recoveries of anaerobic bacteria and more frequent detection of putative periodontal pathogens was observed when microbiological sampling was performed with paper points, in cats with periodontal disease.