A retrospective study on the microbiology in patients with oral complaints and oral mucosal lesions

Microbial Analysis of Obturators During Maxillofacial Prosthodontic Treatment Over an 8-Year Period

The aim of the study was to investigate the microbial colonization (by Candida species, anaerobic and facultative anaerobic bacteria) of maxillary obturators used for the restoration of maxillary defects, including during radiotherapy.

Retrospective cohort study.

Fifteen patients requiring a maxillary obturator prosthesis had swabs of their obturators and adjacent tissues taken at different stages of their treatment over a period of 8 years.

Identification of microbial species from the swabs was carried out using randomly amplified polymorphic DNA polymerase chain reaction (RAPD PCR) analysis, checkerboard DNA-DNA hybridization, CHROMagar Candida chromogenic agar, and DNA sequencing.

Candida species were detected in all patients and all patients developed mucositis and candidiasis during radiotherapy which was associated with an increase in colonization of surfaces with Candida spp., particularly C albicans. Microbial colonization increased during radiotherapy and as an obturator aged, and decreased following a reline, delivery of a new prosthesis, or antifungal treatment during radiotherapy.

Microbial colonization of maxillary obturators was related to the stage of treatment, age of the obturator material, radiotherapy and antifungal medications, and antifungal treatment may be recommended if C albicans colonization of palatal tissues is greater than 105 colony-forming units per cm2 following the first week of radiotherapy.

Comparative Analyses of the Subgingival Microbiome in Chronic Periodontitis Patients with and without Gingival Erosive Oral Lichen Planus Based on 16S rRNA Gene Sequencing

The aim of the study was to compare the microbiota composition and bacterial diversity of subgingival plaque in chronic periodontitis patients with and without gingival erosive oral lichen planus. The subgingival plaque samples of 20 chronic periodontitis patients with gingival erosive oral lichen planus (CP-OLP group) and 19 chronic periodontitis patients without gingival erosive oral lichen planus (CP group) were analyzed by 16S rRNA gene high-throughput sequencing. Compared with the CP group, the richness and diversity of subgingival plaque microflora in the CP-OLP group decreased significantly. There were some differences between the two groups in the composition of microflora on the levels of phylum and genus. Distributions of Prevotella and Leptotrichia in the CP-OLP group were significantly lower than those in the CP group. The dominant genera in CP-OLP group were Pseudomonas and Granulicatella. These results indicated that gingival erosive oral lichen planus may influence the structure and proportion of subgingival plaque microflora.

PCR Detection of HHV8 DNA in the Saliva of Removable Denture Wearers Compared to Dentate Cases in Shiraz, South of Iran

Result

In the denture wearers, HHV8 DNA was detected in 11 cases. Two of the controls amplified HHV8 DNA. Fisher's exact test demonstrates a significant difference between virus infection and using removable dentures (p = 0.015).

Conclusion

Our findings suggested that HHV8 detection could be associated with use of denture.

Non-oral, aerobic, Gram-negative bacilli in the oral cavity of Thai HIV-positive patients on Highly-active anti-retrovirus therapy medication

In the present study, we identified and evaluated the antibiotic susceptibility of 96 independent, aerobic, Gram-negative bacillus isolates from 255 Thai HIV-positive adults who were on Highly-active anti-retrovirus therapy (HAART) medication. Another 46 isolates from HIV non-HAART individuals, vertically transmitted HIV-positive individuals, and non-HIV controls were included for comparison. A total of 103 strains were tested for antibiotic susceptibility using disc diffusion for screening and E-test for minimal inhibitory concentration determination, with special attention on extended-spectrum beta-lactamase (ESBL) isolates. Pseudomonas aeruginosa, Pseudomonas luteola, Burkholderia cepacia, Aeromonas hydrophila, Klebsiella, and Enterobacter species were the most common bacteria. All strains were resistant against penicillin, amoxicillin, clindamycin, and metronidazole. No ESBL isolates were found.

Proteomics of the acid-soluble fraction of whole and major gland saliva in burning mouth syndrome patients

OBJECTIVE

In the present study the salivary proteome of burning mouth syndrome patients and healthy subjects was characterized by a top-down proteomic approach and compared to highlight possible qualitative and quantitative differences that may give suggestions about the causes of this pathology which are still unknown.

MATERIALS AND METHODS

Resting and stimulated whole saliva, stimulated parotid and submandibular/sublingual saliva samples were collected from burning mouth syndrome patients (n = 16) and age- and gender-matched healthy subjects (n = 14). An equal volume of 0.2% trifluoroacetic acid was added to each sample immediately after collection and the supernatants were analysed by liquid chromatography coupled to electrospray-ionisation mass spectrometry. Proteins and peptides were quantified using a label-free approach measuring the extracted ion current peak areas of the main salivary proteins and peptides.

RESULTS

The quantitation of the main salivary proteins and peptides revealed a higher concentration of cystatin SN in resting saliva of burning mouth syndrome patients with respect to healthy controls and no other conspicuous changes.

CONCLUSIONS

The reported data showed that the salivary protein profile was not affected, in composition and relative abundance, by the burning mouth syndrome, except for the cystatin SN, a protein up-regulated in several pathological conditions, that might be considered potentially indicative of the disease.

Significant increase of oral bacteria in the early pregnancy period in Japanese women

AIM

Oral microflora during pregnancy is critical to oral health care in the mother and her child. We examined the changes in the oral microbiota between pregnancy and nonpregnancy periods.

METHODS

The study was performed using 132 healthy pregnant women enrolled from Hiroshima City Asa Citizens Hospital and 51 healthy nonpregnant women as control. During pregnancy, 132 subjects were assessed for seven microbial species by the cultured method and polymerase chain reaction at the early (7-16 weeks gestation), the middle (17-28 weeks), and the late (29-39 weeks) pregnancy periods. Pregnant women completed a series of questionnaires regarding oral and systemic health and lifestyle habits.

RESULTS

The total cultivable microbial counts in the early pregnancy were significantly higher than that of the nonpregnant women (P < 0.05). The incidences of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans in gingival sulcus during the early and middle pregnancy were significantly higher than the nonpregnant group (P < 0.05), while Prevotella intermedia and Fusobacterium nucleatum did not change. Candida species were more frequently detected during the middle and late pregnancy.

CONCLUSION

The data suggest that pregnancy, especially in the early periods, promotes the proliferation of microorganisms in the oral cavity and facilitates a colonization of periodontal pathogens.

Phenotype, genotype, and antibiotic susceptibility of Swedish and Thai oral isolates of Staphylococcus aureus

Objective

The present study investigated phenotypes, virulence genotypes, and antibiotic susceptibility of oral Staphylococcus aureus strains in order to get more information on whether oral infections with this bacterium are associated with certain subtypes or related to an over-growth of the S. aureus variants normally found in the oral cavity of healthy carriers.

Materials and methods

A total number of 157 S. aureus strains were investigated. Sixty-two strains were isolated from Swedish adults with oral infections, 25 strains were from saliva of healthy Swedish dental students, and 45 strains were from tongue scrapings of HIV-positive subjects in Thailand, and 25 Thai strains from non-HIV controls. The isolates were tested for coagulase, nitrate, arginine, and hemolysin, and for the presence of the virulence genes: hlg, clfA, can, sdrC, sdrD, sdrE, map/eap (adhesins) and sea, seb, sec, tst, eta, etb, pvl (toxins). MIC₉₀ and MIC₅₀ were determined by E-test against penicillin V, oxacillin, amoxicillin, clindamycin, vancomycin, fusidic acid, and cefoxitin.

Results

While the hemolytic phenotype was significantly (p<0.001) more common among the Thai strains compared to Swedish strains, the virulence genes were found in a similar frequency in the S. aureus strains isolated from all four subject groups. The Panton-Valentine leukocidin (PVL) genotype was found in 73–100% of the strains. More than 10% of the strains from Swedish oral infections and from Thai HIV-positives showed low antibiotic susceptibility, most commonly for clindamycin. Only three methicillin-resistant S. aureus (MRSA) strains were identified, two from oral infections and one from a Thai HIV patient.

Conclusions

S. aureus is occasionally occurring in the oral cavity in both health and disease in Sweden and Thailand. It is therefore most likely that S. aureus in opportunistic oral infections originate from the oral microbiota. S. aureus should be considered in case of oral infections and complaints and the antibiotic susceptibility (including MRSA) should regularly be checked. The frequent presence of S. aureus, although in low numbers among students and staff, emphasizes the importance of standard infection control precautions and of using diagnostic test in the dental clinic.

Highly-active antiretroviral therapy and oral opportunistic microorganisms in HIV-positive individuals of Thailand

AIM

Oral mucosal lesions and opportunistic microorganisms in HIV-positive Thais treated with highly-active antiretroviral therapy (HAART) for more than 5 years were investigated.

METHODS

A total of 221 HIV-infected patients, comprising 148 HIV patients undergoing HAART for more than 5 years, 20 non-HAART HIV patients, 53 vertically-transmitted (VT) HAART HIV patients, and 30 HIV-negative controls, were examined for CD4+ counts, viral load, saliva secretion rate, and oral mucosal lesions. Samples from the tongue, gingival crevices, and mucosal lesions when present were cultured for the amounts of Candida, staphylococci, enterococci, and aerobic Gram-negative bacilli.

RESULTS

HAART (including HIV-VT) maintained oral microbial homeostasis predominated by alpha-hemolytic streptococci similar to the non-HIV controls and with a low prevalence of mucosal lesions. The HAART group had a reduced saliva secretion rate. The frequency and load of opportunistic microorganisms in the HAART group were similar to the non-HAART group, which was significantly higher than the HIV-negative controls. Candida spp. was found significantly more frequently on the tongue in HIV-infected individuals with CD4+ counts <500 cells/mm(3).

CONCLUSION

Although we did not find lower levels of mucosal lesions among HAART compared to non-HAART individuals, HAART therapy could prolong the time before opportunistic oral pathogens overwhelm the commensal members of oral microbiota.

Prevalence of drug-resistant opportunistic microorganisms in oral cavity after treatment for oral cancer

Drug-resistant opportunistic infections may cause health problems in immunocompromised hosts. Representative microorganisms in opportunistic infections of the oral cavity are Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. We investigated the prevalence of drug-resistant opportunistic microorganisms in elderly adults receiving follow-up examinations after primary treatment of oral cancer. Oral microorganisms were collected from patients satisfactorily treated for oral cancer (defined as good outcomes to date) and a group of healthy adults (controls). After identification of microorganisms, the prevalence of drug-resistant microorganisms was studied. Pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome mec (SCCmec) typing were also performed for methicillin-resistant S aureus (MRSA). Statistical analysis revealed no significant differences in the prevalences of the three microorganisms between the groups. Surprisingly, 69.2% of S aureus isolates showed oxacillin resistance, suggesting that MRSA colonization is increasing among older Japanese. These MRSA isolates possessed SCCmec types II and IV but no representative toxin genes. Our results indicate that a basic infection control strategy, including standard precautions against MRSA, is important for elderly adults, particularly after treatment for oral cancer.

Oral complications in hematopoietic stem cell recipients: the role of inflammation

Hematopoietic stem cell transplantation (HSCT) is widely used as a potentially curative treatment for patients with various hematological malignancies, bone marrow failure syndromes, and congenital immune deficiencies. The prevalence of oral complications in both autologous and allogeneic HSCT recipients remains high, despite advances in transplant medicine and in supportive care. Frequently encountered oral complications include mucositis, infections, oral dryness, taste changes, and graft versus host disease in allogeneic HSCT. Oral complications are associated with substantial morbidity and in some cases with increased mortality and may significantly affect quality of life, even many years after HSCT. Inflammatory processes are key in the pathobiology of most oral complications in HSCT recipients. This review article will discuss frequently encountered oral complications associated with HSCT focusing on the inflammatory pathways and inflammatory mediators involved in their pathogenesis.

Periodontal status and bacteremia with oral viridans streptococci and coagulase negative staphylococci in allogeneic hematopoietic stem cell transplantation recipients: a prospective observational study

AIM

This study was aimed to investigate whether any association could be found between the presence of an inflamed and infected periodontium (e.g., gingivitis and periodontitis) and the development of bacteremia during neutropenia following allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

Eighteen patients underwent a periodontal examination before HSCT. Patients were classified as periodontally healthy [all periodontal pocket depths (PPD) ≤ 4 mm and bleeding on probing (BOP) ≤ 10%) or as having gingivitis/periodontitis (PPD ≥ 4 mm and BOP > 10%]. Oral mucositis (OM) was scored using the daily mucositis score. Blood cultures were taken at least twice weekly.

RESULTS

Five patients were periodontally healthy, while 13 patients had gingivitis or periodontitis. Twelve patients (67%) developed bacteremia during neutropenia, of which 11 patients (61%) had one or more episodes of bacteremia due to coagulase-negative staphylococci (CONS, most often Staphylococcus epidermidis) or to oral viridans streptococci (OVS), or both. Patients with gingivitis/periodontitis more often had bacteremia than those with a healthy periodontium (p = 0.047), and BOP was associated with bacteremia (p = 0.049). All patients developed ulcerative OM, but its severity and duration were not associated with bacteremia. OM duration and the length of stay in the hospital were strongly correlated (R = 0.835, p ≤ 0.001).

CONCLUSION

This study indicates that periodontal infections may contribute to the risk of developing OVS and CONS bacteremia during neutropenia following HSCT. While our results point to the importance of periodontal evaluation and management before HSCT, further studies on periodontal contribution to systemic infectious complications are warranted.

Clinical and histological findings of denture stomatitis as related to intraoral colonization patterns of Candida albicans, salivary flow, and dry mouth

PURPOSE

Multifactorial etiological factors contribute to denture stomatitis (DS), a type of oral candidiasis; however, unlike other oral candidiasis, DS can occur in a healthy person wearing a denture. In this study, we therefore attempt to explore the association between candida, denture, and mucosal tissue using (1) exfoliative cytology, (2) the candidal levels present in saliva, on mucosal tissues and on denture surfaces, and (3) the salivary flow rate and xerostomic symptoms.

MATERIALS AND METHODS

A cross-sectional study enrolled 32 edentulous participants, 17 without DS as controls and 15 with DS (Newton's classification type II and III). Participants with systemic or other known oral conditions were excluded. Participants completed a xerostomia questionnaire, and salivary flow rates were measured. Samples of unstimulated whole saliva (UWS) and stimulated whole saliva (SWS) were collected. UWS was used for fungal culturing. Periodic acid-Schiff (PAS) stain and quantitative exfoliative cytology were performed on samples from affected and unaffected mucosa from each participant. Levels of Candida species (albicans and non-albicans) were determined in salivary samples (expressed as colony-forming units, CFU), as well as from swab samples obtained from denture fitting surfaces, in addition to affected and unaffected mucosa.

RESULTS

There were no significant differences in salivary flow rates, mucosal wetness, or frequency of reported dry mouth comparing participants with and without DS. Exfoliative cytology of mucosal smears demonstrated significantly higher (p= 0.02) inflammatory cell counts in DS patients, as compared with smears of healthy denture-wearers. Candida albicans was significantly more prevalent in saliva (p= 0.03) and on denture surfaces (p= 0.002) of DS participants, whereas mucosal candidal counts and the presence of cytological hyphae did not show significant difference comparing DS to healthy participants.

CONCLUSIONS

In this investigation, we presented a unique group of healthy edentulous patients. This population may reflect the general DS population without systemic or other oral diseases. The prominent etiological factor for DS in this population is the presence of candida in denture and saliva. We found that other factors such as saliva flow/xerostomia, fitting of the denture, and the presence of candida in the mucosa, are less important in this population. Therefore, DS treatments in healthy patients should first focus on sanitization of an existing denture and/or fabrication of a new denture.

Orofacial diseases in solid organ and hematopoietic stem cell transplant recipients

OBJECTIVE

Solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients are at risk of several diseases, principally attributable to immunosuppression. This global overview of SOT/HSCT-associated orofacial diseases is aimed at providing a practical instrument for the oral healthcare management of SOT/HSCT recipients.

METHODS

Literature search was made through MEDLINE. The associations between orofacial diseases and SOT/HSCT were assessed using observational studies and case series and were classified into 'association', 'no association', and 'unclear association'.

RESULTS

Lip/oral cancers, drug-induced gingival overgrowth (DIGO), infections, including hairy leukoplakia and, less frequently, post-transplantation lymphoproliferative disorders (PTLDs) and oral lichenoid lesions of graft-versus-host disease (GVHD), were associated with SOT. Lip/oral cancers, GVHD, mucositis, DIGO, infections and, less frequently, PTLDs were associated with HSCT. Associations of orofacial granulomatosis-like lesions and oral mucosa-associated lymphoid tissue-type lymphoma with SOT, and of pyogenic granuloma and hairy leukoplakia with HSCT were unclear. Periodontal disease and dental caries were not associated with SOT/HSCT. For none of the local treatments was there a strong evidence of effectiveness.

CONCLUSIONS

Solid organ transplant/HSCT recipients are at risk of orofacial diseases. Adequate management of these patients alleviates local symptoms responsible for impaired eating, helps prevent systemic and lethal complications, and helps where dental healthcare has been neglected.

Virulence factors and antibiotic susceptibility in enterococci isolated from oral mucosal and deep infections

OBJECTIVE

This study evaluates the presence of virulence factors and antibiotic susceptibility among enterococcal isolates from oral mucosal and deep infections.

METHODS

Forty-three enterococcal strains from oral mucosal lesions and 18 from deep infections were isolated from 830 samples that were sent during 2 years to Oral Microbiology, University of Gothenburg, for analysis. The 61 strains were identified by 16S rDNA, and characterized by the presence of the virulence genes efa A (endocarditis gene), gel E (gelatinase gene), ace (collagen binding antigen gene), asa (aggregation substance gene), cyl A (cytolysin activator gene) and esp (surface adhesin gene), tested for the production of bacteriocins and presence of plasmids. MIC determination was performed using the E-test method against the most commonly used antibiotics in dentistry, for example, penicillin V, amoxicillin and clindamycin. Vancomycin was included in order to detect vancomycin-resistant enterococci (VRE) strains.

RESULTS

Sixty strains were identified as Enterococcus faecalis and one as Enterococcus faecium. All the virulence genes were detected in more than 93.3% (efa A and esp) of the E. faecalis strains, while the presence of phenotypic characteristics was much lower (gelatinase 10% and hemolysin 16.7%). Forty-six strains produced bacteriocins and one to six plasmids were detected in half of the isolates.

CONCLUSIONS

Enterococcal strains from oral infections had a high virulence capacity, showed bacteriocin production and had numerous plasmids. They were generally susceptible to ampicillins but were resistant to clindamycin, commonly used in dentistry, and no VRE-strain was found.

Candida invasion and influences in smoking patients with multiple oral leucoplakias--a retrospective study

Treating patients with multiple oral leucoplakias (MOLs) who smoke is more difficult and complicated than treating those with single oral leucoplakia (SOL). Removing the aetiological factors causing MOL can effectively prevent its recurrence. The aim was to study the infection by and influences of Candida in smoking patients with MOLs. A retrospective study was conducted on 136 smoking patients who had clinicopathological OLs. Among these patients, 73 lesions in 31 patients were MOLs, while 105 patients had SOLs. All patients were treated by complete resection. All specimens were tested for epithelial dysplasia, and stained with periodic acid-Schiff reagent. The rate of MOL concurrence with candidal infection was higher than that of SOLs. The incidence of Candida associated with MOLs was higher for recurrent than for non-recurrent lesions. The disease-free time was shorter in MOL patients with candidal infection. Moreover, MOLs with candidal infection were more likely to have an increasing ratio to combine with epithelial dysplasia. Candida is an important risk factor in smoking patients with MOLs. Microscopic and fungal examinations of those lesions should permit a detailed diagnosis in such patients and for long-term predictive assessments.

Characterization of mucosal Candida albicans biofilms

C. albicans triggers recurrent infections of the alimentary tract mucosa that result from biofilm growth. Although the ability of C. albicans to form a biofilm on abiotic surfaces has been well documented in recent years, no information exists on biofilms that form directly on mucosal surfaces. The objectives of this study were to characterize the structure and composition of Candida biofilms forming on the oral mucosa. We found that oral Candida biofilms consist of yeast, hyphae, and commensal bacteria, with keratin dispersed in the intercellular spaces. Neutrophils migrate through the oral mucosa and form nests within the biofilm mass. The cell wall polysaccharide β-glucan is exposed during mucosal biofilm growth and is more uniformly present on the surface of biofilm organisms invading the oral mucosa. We conclude that C. albicans forms complex mucosal biofilms consisting of both commensal bacterial flora and host components. These discoveries are important since they can prompt a shift of focus for current research in investigating the role of Candida-bacterial interactions in the pathogenesis of mucosal infections as well as the role of β-glucan mediated signaling in the host response.