Genetic typing of Candida albicans strains isolated from the oral cavity of patients with denture stomatitis before and after itraconazole therapy

This study determined, by molecular typing of C. albicans species isolated from denture stomatitis patients with a mycological relapse six months after successful itraconazole therapy, whether there had been recurrence of infection with the same strain(s), selection of particular strains or infection with new strains of C. albicans. Forty patients with long-standing Candida-associated denture stomatitis were assigned either cyclodextrin itraconazole solution or itraconazole capsules (100mg b.d. for 15 days). Palatal erythema was measured and imprint cultures undertaken at baseline and at 15 days, four weeks and six months after treatment commenced. Yeast isolates were formally identified and chromosomal DNA was extracted from pairs of isolates from those patients with C. albicans present at baseline and six months after treatment commenced. Southern blotting of EcoRI-digested chromosomal DNA was performed using the C. albicans-specific 27A repetitive element as a probe. Eighteen of 36 patients were infected with C. albicans at baseline and six months after treatment commenced. Overall, 13 genetically different strains of C. albicans were found. However, in 17 of 18 patients, the C. albicans strains isolated prior to itraconazole therapy and six months later were the same. Thus recurrence of denture stomatitis in these individuals was due to re-colonisation by the original strain, rather than re-infection with a different strain. Key words: Genotyping, C. albicans, denture stomatitis

Black-pigmented anaerobic bacteria associated with ovine periodontitis

Periodontitis is a polymicrobial infectious disease that causes occlusion change, tooth loss, difficulty in rumination, and premature culling of animals. This study aimed to detect species of the genera Porphyromonas and Prevotella present in the periodontal pocket of sheep with lesions deeper than 5mm (n=14) and in the gingival sulcus of animals considered periodontally healthy (n=20). The presence of microorganisms was evaluated by polymerase chain reaction (PCR) using specific primers for Porphyromonas asaccharolytica, Porphyromonas endodontalis, Porphyromonas gingivalis, Porphyromonas gulae, Prevotella buccae, Prevotella intermedia, Prevotella loescheii, Prevotella melaninogenica, Prevotella nigrescens, Prevotella oralis, and Prevotella tannerae. Prevalence and risk analysis were performed using Student's t-test and Spearman's correlation. Among the Prevotella and Porphyromonas species detected in the periodontal lesions of sheep, P. melaninogenica (85.7%), P. buccae (64.3%), P. gingivalis (50%), and P. endodontalis (50%) were most prevalent. P. gingivalis (15%) and P. oralis (10%) prevailed in the gingival sulcus. P. gulae and P. tannerae were not detected in the 34 samples studied. Data evaluation by t-test verified that occurrence of P. asaccharolytica, P. endodontalis, P. gingivalis, P. buccae, P. intermedia, P. melalinogenica, and P. nigrescens correlated with sheep periodontitis. The findings of this study will be an important contribution to research on pathogenesis of sheep periodontitis and development of its control measures

Prevalence of feline calicivirus in cats with odontoclastic resorptive lesions and chronic gingivostomatitis

Feline odontoclastic resorptive lesion (FORL) and feline chronic gingivostomatitis (FCGS) are two of the most common diseases of the feline oral cavity. While evidence is emerging that FCGS is caused by gingival inflammation initiated and perpetuated by the oral microbiota, little is known in this regard for FORL. Feline calicivirus (FCV) has been associated with the presence of FCGS and is thought to play a role in the initiation of this disease. In this study, the incidence of FCV was investigated in cats with FORL and FCGS, and compared to unaffected controls. FCV was detected by viral culture. The incidence of FCV was as follows: 6 (24.0%) of 24 control cats, 9 (22.5%) of 40 cats with FORL and 15 (60.0%) of 25 cats with FCGS were positive for FCV. There was a significant difference in FCV incidence between all the groups (p = 0.003) but none between the control group and the FORL group. However, significant differences were observed in the incidence of FCV between control and FCGS (p = 0.010) and between FORL and FCGS (p = 0.006). It is concluded that although FCV may be associated with FCGS, it appears unlikely to play a role in FORL

Identification of bacteria on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties by 16S rRNA gene sequencing and by microbiological culture

It has been postulated that bacteria attached to the surface of prosthetic hip joints can cause localised inflammation, resulting in failure of the replacement joint. However, diagnosis of infection is difficult with traditional microbiological culture methods, and evidence exists that highly fastidious or non-cultivable organisms have a role in implant infections. The purpose of this study was to use culture and culture-independent methods to detect the bacteria present on the surface of prosthetic hip joints removed during revision arthroplasties. Ten consecutive revisions were performed by two surgeons, which were all clinically and radiologically loose. Five of the hip replacement revision surgeries were performed because of clinical infections and five because of aseptic loosening. Preoperative and perioperative specimens were obtained from each patient and subjected to routine microbiological culture. The prostheses removed from each patient were subjected to mild ultrasonication to dislodge adherent bacteria, followed by aerobic and anaerobic microbiological culture. Bacterial DNA was extracted from each sonicate and the 16S rRNA gene was amplified with the universal primer pair 27f/1387r. All 10 specimens were positive for the presence of bacteria by both culture and PCR. PCR products were then cloned, organised into groups by RFLP analysis and one clone from each group was sequenced. Bacteria were identified by comparison of the 16S rRNA gene sequences obtained with those deposited in public access sequence databases. A total of 512 clones were analysed by RFLP analysis, of which 118 were sequenced. Culture methods identified species from the genera Leifsonia (54.3%), Staphylococcus (21.7%), Proteus (8.7%), Brevundimonas (6.5%), Salibacillus (4.3%), Methylobacterium (2.2%) and Zimmermannella (2.2%). Molecular detection methods identified a more diverse microflora. The predominant genus detected was Lysobacter, representing 312 (60.9%) of 512 clones analysed. In all, 28 phylotypes were identified: Lysobacter enzymogenes was the most abundant phylotype (31.4%), followed by Lysobacter sp. C3 (28.3%), gamma proteobacterium N4-7 (6.6%), Methylobacterium SM4 (4.7%) and Staphylococcus epidermidis (4.7%); 36 clones (7.0%) represented uncultivable phylotypes. We conclude that a diverse range of bacterial species are found within biofilms on the surface of clinically infected and non-infected prosthetic hip joints removed during revision arthroplasties

Community analysis of dental plaque and endotracheal tube biofilms from mechanically ventilated patients

© 2017 Elsevier Inc. Purpose Mechanically ventilated patients are at risk for developing ventilator-associated pneumonia, and it has been reported that dental plaque provides a reservoir of respiratory pathogens that may aspirate to the lungs and endotracheal tube (ETT) biofilms. For the first time, metataxonomics was used to simultaneously characterize the microbiome of dental plaque, ETTs, and non-directed bronchial lavages (NBLs) in mechanically ventilated patients to determine similarities in respective microbial communities and therefore likely associations. Material and methods Bacterial 16S rRNA gene sequences from 34 samples of dental plaque, NBLs, and ETTs from 12 adult mechanically ventilated patients were analyzed. Results No significant differences in the microbial communities of these samples were evident. Detected bacteria were primarily oral species (e.g., Fusobacterium nucleatum, Streptococcus salivarius, Prevotella melaninogenica) with respiratory pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pneumoniae, and Haemophilus influenzae) also in high abundance. Conclusion The high similarity between the microbiomes of dental plaque, NBLs, and ETTs suggests that the oral cavity is indeed an important site involved in microbial aspiration to the lower airway and ETT. As such, maintenance of good oral hygiene is likely to be highly important in limiting aspiration of bacteria in this vulnerable patient group

Evaluation of tissue levels of Toll-like receptors and cytokine mRNAs associated with bovine periodontitis and oral health

Bovine periodontitis is a progressive and purulent infection associated with an anaerobic subgingival biofilm, which induces irreversible damage to the dentition of affected animals. The aetiopathogenesis of the disease is unclear and treatment and control of the disease process in cattle are almost unknown. The aim of this study was to investigate the innate immune response by quantifying expression of Toll-like receptor (TLR) and cytokine genes in gingival tissue samples from cattle with and without periodontitis. Postmortem biopsies of gingival tissues were collected from 20 cattle with periodontitis and 20 cattle with no clinical signs of periodontal lesions. Tissue expression of TLR2, TLR4, TNF-α, IFN-γ, IL-1β and IL-4 genes were determined using quantitative real-time PCR. Statistically significant increases in mRNA levels encoding TLR2 (p = 0.025), TLR4 (p = 0.037), TNF-α (p = 0.025), IFN-γ (p = 0.014), IL-1β (p < 0.001) and IL-4 (p = 0.014) were observed in animals with periodontitis when compared to periodontally healthy animals. Increased levels of TLRs and inflammatory cytokines in periodontal tissue indicate an induction of the innate immune response of cattle and suggest that a substantial microbial challenge may be involved in the aetiopathogenesis of bovine periodontitis

Microbiomes associated with bovine periodontitis and oral health

Periodontitis is an infectious polymicrobial, immuno-inflammatory disease of multifactorial aetiology that has an impact on the health, production and welfare of ruminants. The objective of the present study was to determine the microbial profiles present in the gingival sulcus of cattle considered periodontally healthy and in the periodontal pocket of animals with periodontitis lesions using high-throughput bacterial 16S rRNA gene sequencing. Subgingival biofilm samples were collected from 40 cattle with periodontitis and 38 periodontally healthy animals. In total, 1923 OTUs were identified and classified into 395 genera or higher taxa. Microbial profiles in health differed significantly from periodontitis in their composition (p < 0.0001, F = 5.30; PERMANOVA) but no statistically significant differences were observed in the diversity of healthy and periodontitis microbiomes. The most prevalent taxa in health were Pseudomonas, Burkholderia and Actinobacteria, whereas in disease these were Prevotella, Fusobacterium and Porphyromonas. The most discriminative taxa in health were Gastranaerophilales, Planifilum and Burkholderia, and in disease these were Elusimicrobia, Synergistes and Propionivibrio. In conclusion, statistically significant difference exists between the microbiome in bovine oral health and periodontitis, with populations showing 72.6% dissimilarity. The diversity of the bacteria found in health and periodontitis were similar and bacteria recognised as periodontal pathogens showed increased abundance in disease. In this context, the main components of bacterial homeostasis in the biofilm of healthy sites and of dysbiosis in periodontal lesions provide unprecedented indicators for the evolution of knowledge about bovine periodontitis

Age Reflects on the Occurrence of Bovine Periodontal Lesions

No abstract available

Dental biofilm and its ecological interrelationships in ovine periodontitis

Introduction. Periodontitis, one of the most common oral disorders in sheep, is caused by a mixed and opportunistic microbiota that severely affects the health and welfare of animals. However, little is known about the ecological processes involved and the composition of the microbiota associated with the development of the disease. Hypothesis/Gap Statement. Using high-throughput sequencing of the 16S ribosomal RNA gene and network analysis it would be possible to discriminate the microbiomes of clinically healthy sheep and those with periodontitis and possibly identify the key microorganisms associated with the disease. Aim. The present study aimed to characterise the composition of dental microbiomes and bacterial co-occurrence networks in clinically healthy sheep and animals with periodontitis. Methodology. Dental biofilm samples were collected from ten sheep with periodontitis and ten clinically healthy animals. Bacteria were identified using high-throughput sequencing of the 16S ribosomal RNA gene. Results. The most prevalent genera in the dental microbiota of sheep with periodontitis were Petrimonas , Acinetobacter , Porphyromonas and Aerococcus . In clinically healthy animals, the most significant genera were unclassified Pasteurellaceae, Pseudomonas, and Neisseria. Fusobacterium was found at high prevalence in the microbiomes of both groups. The dental microbiota of sheep in the two clinical conditions presented different profiles and the diversity and richness of bacteria was greater in the diseased animals. Network analyses showed the presence of a large number of antagonistic interactions between bacteria in the dental microbiota of animals with periodontitis, indicating the occurrence of a dysbiotic community. Through the interrelationships, members of the Prevotella genus are likely to be key pathogens, both in the dental microbiota of healthy animals and those with periodontitis. Porphyromonas stood out among the top three nodes with more centrality and the largest number of hubs in the networks of animals with periodontitis. Conclusion. The dental biofilm microbiota associated with ovine periodontitis is dysbiotic and with significant antagonistic interactions, which discriminates healthy animals from diseased animals and highlights the importance of key bacteria, such as Petrimonas , Porphyromonas , Prevotella and Fusobacterium species

Microbiome analysis of feline odontoclastic resorptive lesion (FORL) and feline oral health

Introduction. Feline odontoclastic resorptive lesion (FORL) is one of the most common and painful oral diseases of the cat. It is characterised by tooth resorption due to destructive activity of odontoclasts. FORL can result in tooth loss. While the aetiology of FORL is not clearly understood, it is thought to be multifactorial and bacteria are likely to play a major role. Hypothesis. Dysbiosis of the normal feline oral microbiota leads to an alteration in commensal bacteria populations, which results in the development of FORL. Aim. The purpose of the current study was to determine the composition of the microbiomes associated with feline oral health and FORL. Methodology. Supragingival plaque was collected from 25 cats with a healthy oral cavity and 40 cats with FORL. DNA was extracted from each sample, the V4 region of the 16S rRNA gene amplified by polymerase chain reaction and amplicons sequenced. Diversity and species richness analyses were performed, principal component analysis was used to explore differences between the oral microbiomes of healthy cats and those with FORL, and linear discriminant analysis effect size was used to assess differences between the groups. Results. The six most abundant bacterial genera identified were Bergeyella , Capnocytophaga, Lampropedia, Morexella, Porphyromonas and Treponema . Two-step cluster analysis of the data identified two FORL sub-groups (FORL-1, FORL-2). The FORL-2 sub-group was very similar to the healthy group, whilst the FORL-1 sub-group was clearly different from both the FORL-2 sub-group and the healthy groups. In this analysis, Capnocytophaga (P <0.001) and Lampropedia (P <0.01) were found at significantly lower levels and Porphyromonas at a slightly higher level in the FORL-1 sub-group compared to the healthy and FORL-2 sub-groups. Microbial diversity was found to be less in the FORL-1 sub-group than in the healthy group. Lampropedia sp., a phosphate-accumulating oral commensal species, was significantly lower in the FORL-1 sub-group. Conclusion. The oral microbiota associated with the FORL-1 sub-group is distinct from that found in the healthy group and FORL-2 sub-group. Lampropedia species may influence the local calcium-phosphate ratio, which could be a factor in tooth and bone resorption observed in FORL