The prevalence of Staphylococcus aureus, Enterobacteriaceae species, and Candida species and their relation to oral mucosal lesions in a group of 79-year-olds in Göteborg

Are the counts of Streptococcus mutans and Staphylococcus aureus changed in complete denture wearers carrying denture stomatitis? A systematic review with meta-analyses

STATEMENT OF PROBLEM

Despite the importance of Candida spp. on the etiology of denture stomatitis (DS), information on the role of the bacterial component is still scarce.

PURPOSE

The purpose of this systematic review was to evaluate whether the counts of Staphylococcus aureus and Streptococcus mutans were changed in complete denture wearers diagnosed with Candida-associated DS.

MATERIAL AND METHODS

The literature search was performed in 8 databases and by hand searching. The risk of bias was assessed according to the Newcastle-Ottawa qualifier. Meta-analyses were performed considering the microorganism evaluated (S. aureus or S. mutans) and the collection area (mucosa or dentures). The certainty of evidence was assessed according to the grading of recommendations assessment, development and evaluations (GRADE) criteria.

RESULTS

Participants with DS presented higher counts of S. aureus in the mucosa compared with those from the control group (OR, 3.16 [1.62, 6.15]; P<.001). No significant difference between the groups was observed for samples collected from dentures (OR, 0.73 [0.50, 1.07]; P=.110). Conversely, participants without DS presented higher counts of S. mutans both in the mucosa (OR, 0.19 [0.06, 0.63]; P=.006) and dentures (OR, 0.64 [0.41, 1.0]; P=.050).

CONCLUSIONS

Microbial counts in participants with DS changed as a function of the type of microorganism and collection site. The certainty of evidence ranged from very low to low. The findings reinforce the fact that bacteria also play a relevant role in DS and should be more extensively studied. Such information may be useful to guide further therapies to prevent or control DS.

Periodontal microorganisms and Alzheimer disease - A causative relationship?

In the initiation or exacerbation of Alzheimer disease, the dissemination of oral microorganisms into the brain tissue or the low‐level systemic inflammation have been speculated to play a role. However, the impact of oral microorganisms, such as Porphyromonas gingivalis, on the pathogenesis of Alzheimer disease and the potential causative relationship is still unclear. The present review has critically reviewed the literature by examining the following aspects: (a) the oral microbiome and the immune response in the elderly population, (b) human studies on the association between periodontal and gut microorganisms and Alzheimer disease, (c) animal and in vitro studies on microorganisms and Alzheimer disease, and (d) preventive and therapeutic approaches. Factors contributing to microbial dysbiosis seem to be aging, local inflammation, systemic diseases, wearing of dentures, living in nursing homes and no access to adequate oral hygiene measures. Porphyromonas gingivalis was detectable in post‐mortem brain samples. Microbiome analyses of saliva samples or oral biofilms showed a decreased microbial diversity and a different composition in Alzheimer disease compared to cognitively healthy subjects. Many in‐vitro and animal studies underline the potential of P gingivalis to induce Alzheimer disease‐related alterations. In animal models, recurring applications of P gingivalis or its components increased pro‐inflammatory mediators and β‐amyloid in the brain and deteriorated the animals' cognitive performance. Since periodontitis is the result of a disturbed microbial homoeostasis, an effect of periodontal therapy on the oral microbiome and host response related to cognitive parameters may be suggested and should be elucidated in further clinical trials.

Occurrence of Candida species colonization in a population of denture-wearing immigrants

Infection of the oral cavity and dentures by Candida species are frequent in denture wearers. C. albicans is the most common pathogen; however, other emerging Candida species are also responsible for this condition. Few data are available about the occurrence of Candida species in the oral cavities of denture-wearing immigrants to Italy. In this study, we compare the Candida species found in the oral mucosa and on dentures from a population of denture wearing immigrants to Italy to a matched Italian group. Oral swabs were collected from dentures and the underlying mucosa of patients enrolled in the study and were then cultured to test for the presence of Candida species in each sample. Out of 168 patients enrolled (73 Italians and 95 immigrants), 51 Italians (69.8 percent) and 75 immigrants (78.9 percent) tested positive for the presence of Candida. Candida albicans was the most frequently observed species overall; however, we found a higher occurrence of C. glabrata among immigrants than among Italians. In addition, immigrants displayed a higher incidence of Candida – associated stomatitis and a lower mean age than Candida-positive individuals from the Italian group. Immigrants are more prone to longer colonization of the oral mucosa and dentures by Candida. In these patients, dentures must be checked periodically to prevent the presence of Candida.

Antimicrobial properties and cytotoxicity of an antimicrobial monomer for application in prosthodontics

PURPOSE

This study aimed to investigate the antimicrobial properties and cytotoxicity of the monomer methacryloyloxyundecylpyridinium bromide (MUPB), an antiseptic agent capable of copolymerizing with denture base acrylic resins.

MATERIALS AND METHODS

The antimicrobial activity of MUPB was tested against the species Candida albicans, Candida dubliniensis, Candida glabrata, Lactobacillus casei, Staphylococcus aureus, and Streptococcus mutans. The minimum inhibitory and fungicidal/bactericidal concentrations (MIC, MFC/MBC) of MUPB were determined by serial dilutions in comparison with cetylpyridinium chloride (CPC). The cytotoxic effects of MUPB at concentrations ranging from 0.01 to 1 g/L were assessed by MTT test on L929 cells and compared with methyl methacrylate (MMA). The antimicrobial activity of copolymerized MUPB was tested by means of acrylic resin specimens containing three concentrations of the monomer (0, 0.3, 0.6% w/w). Activity was quantified by means of a disc diffusion test and a quantification of adhered planktonic cells. Statistical analysis employed the Mann-Whitney test for MIC and MFC/MBC, and ANOVA for the microbial adherence test (α = 0.05).

RESULTS

MUBP presented lower MIC values when compared with CPC, although differences were significant for C. dubliniensis and S. mutans only (p= 0.046 and 0.043, respectively). MFC/MBC values were similar for all species except C. albicans; in that case, MUPB presented significantly higher values (p = 0.046). MUPB presented higher cytotoxicity than MMA for all tested concentrations (p < 0.001) except at 0.01 g/L. Irrespective of the concentration incorporated and species, there was no inhibition halo around the specimens. The incorporation of MUPB influenced the adhesion of C. albicans only (p = 0.003), with lower CFU counts for the 0.6% group.

CONCLUSIONS

It was concluded that non-polymerized MUPB has an antimicrobial capacity close to that of CPC and high cytotoxicity when compared with MMA. The antimicrobial activity of MUPB after incorporation within a denture base acrylic resin did not depend on its elution, but was shown to be restricted to C. albicans.

Staphylococcus spp., Enterobacteriaceae and Pseudomonadaceae oral isolates from Brazilian HIV-positive patients. Correlation with CD4 cell counts and viral load

The aim was to evaluate the presence of Staphylococcus spp., Enterobacteriaceae and Pseudomonadaceae in the oral cavities of HIV-positive patients. Forty-five individuals diagnosed as HIV-positive by ELISA and Western-blot, and under anti-retroviral therapy for at least 1 year, were included in the study. The control group constituted 45 systemically healthy individuals matched to the HIV patients to gender, age and oral conditions. Oral rinses were collected and isolates were identified by API system. Counts of microorganisms from HIV and control groups were compared statistically by a Mann-Whitney test (α=5%). The percentages of individuals positive for staphylococci were similar between the groups (p=0.764), whereas for Gram-negative rods, a higher percentage was observed amongst HIV-positive (p=0.001). There was no difference in Staphylococcus counts between HIV and control groups (p=0.1008). Counts were lower in the oral cavities of patients with low viral load (p=0.021), and no difference was observed in relation to CD4 counts (p=0.929). Staphylococcus aureus was the most frequently isolated species in HIV group, and Staphylococcus epidermidis was the prevalent species in the control group. Significantly higher numbers of enteric bacteria and pseudomonas were detected in the oral cavities of the HIV group than in the control (p=0.0001). Enterobacter cloacae was the most frequently isolated species in both groups. Counts of enteric bacteria and pseudomonas were significantly lower in patients with low CD4 counts (p=0.011); however, there was no difference relating to viral load. It may be concluded that HIV group showed greater species diversity and a higher prevalence of Enterobacteriaceae/Pseudomonadaceae.

Detection and hazard assessment of pathogenic microorganisms in medical wastes

This study was undertaken to investigate the types and concentrations of microbial agents in various medical wastes as well as to characterize their survivals in these wastes at different temperatures for microbial risk assessment. Medical wastes collected from 5 major hospitals in South Korea were classified and stored at three different temperatures (-20, 6, and 30 degrees C). Presence of various microorganisms such as pathogenic viruses and bacteria were investigated by both cultivation and by (RT)-PCR assays. A number of (opportunistic) pathogenic bacteria, including Pseudomonas spp., Lactobacillus spp., Staphylococcus spp., Micrococcus spp., Kocuria spp., Brevibacillus spp., Microbacterium oxydans, and Propionibacterium acnes, were identified from the various medical wastes. In addition, pathogenic viruses such as noroviruses and hepatitis B virus were also detected in one of the human tissue wastes. Commonly identified bacterial and viral pathogens such as Pseudomonas spp., Corynebacterium diphtheriae, Escherichia coli, Staphylococcus spp., and respiratory synctial virus (RSV) were inoculated into either gauzes or diapers, and their survivals were characterized. Viral agents such as RSV showed poor survival in most environmental conditions, and demonstrated that various pathogens could be present in medical wastes but that the associated health risk appeared to be low. However, medical waste should be carefully controlled and monitored to prevent nosocomial infection associated with the exposure to these wastes.

Candida glabrata: an emerging oral opportunistic pathogen

Following the widespread use of immunosuppressive therapy and broad-spectrum antimycotic prophylaxis, C. glabrata has emerged as an important opportunistic pathogen in the oral mucosa. In the past, studies on the virulence factors and host-pathogen interactions of this organism were scarce, but continued to rise in recent years. Denture-wearing, immunosuppression, antibiotic therapy, and aging are risk factors for oral colonization or infection with C. glabrata. Compared with C. albicans, C. glabrata exhibits lower oral keratinocyte-adherence capacity, but higher denture-surface-adherence ability. The role of extracellular hydrolase production in the virulence of this organism does not appear to be as important as it is in C. albicans pathogenesis. Although traditionally thought of as a non-transforming yeast organism, both phenotypic switching and pseudohyphal formation have recently been identified in C. glabrata, but their role in pathogenesis is not known. With the exception of granulocyte monocyte colony-stimulating factor, C. glabrata triggers a lower proinflammatory cytokine response in oral epithelial cells than does C. albicans, in a strain-dependent manner. C. glabrata is less susceptible to killing by human beta-defensins than is C. albicans and exhibits various degrees of resistance to the antifungal activity of salivary histatins and mucins. In addition, C. glabrata possesses both innate and acquired resistance against antifungal drugs, due to its ability to modify ergosterol biosynthesis, mitochondrial function, or antifungal efflux. This resistance allows for its relative overgrowth over other susceptible species and may contribute to the recent emergence of C. glabrata infections in chronically immunocompromised populations. Further investigations on the virulence and host-pathogen interactions of C. glabrata are needed to better define the pathogenesis of oral C. glabrata infection in susceptible hosts.

Microbiological diagnostics in oral diseases

Most infections of the oral cavity, including the major dental diseases caries and periodontitis, are opportunistic in nature. They are caused or maintained by microorganisms of the resident or transient flora normally present in low numbers and not pathogenic, but in certain circumstances develop infections. Mucosal infections have some degree of specificity [e.g. Candida spp., Staphylococcus aureus, and enterics] and a microbiological test can be interpreted accurately for clinical diagnosis and choice of treatment. Subepithelial or deep infections, however, include a number of species from the resident flora, mainly anaerobes whose role in the infections is difficult to interpret. However, microbiological tests and the presence of certain bacterial species could be used for treatment control, risk-evaluation and even for patient motivation in the prevention of these diseases. Microbiological diagnosis can be used in general practice for several purposes and in various situations that can be of great value for the dental patient.

Transient oral microflora in Greeks attending day centres for the elderly and residents in homes for the elderly

OBJECTIVE

To examine the isolation frequency and the carriage of yeasts, Enterobacteriaceae, Staphylococcus and Enterococcus species in oral samples from elderly Greeks living alone or in institutions.

BACKGROUND

Ageing may promote changes in the oral ecosystem, which lead to colonisation of the mouth by microbes found less commonly or only transiently in younger subjects. Previous studies indicate a geographical variation in the isolation frequency of such bacteria in elderly populations.

MATERIALS AND METHODS

Medical and dental records were obtained from 66 attenders at elderly people's day centres (EPDC), and 82 residents of elderly people's homes (EPH), 66-95 years old. Mucosa smear samples were cultured on appropriate media for enumeration of the above species. Microbial identification was performed by conventional microbiological tests. The results were analysed using the Multiple Correspondence Analysis (MCA), ANOVA and other traditional statistical tests.

RESULTS

No statistically significant association was found between the place of residence and the wearing of dentures. The isolation frequencies of Staphylococcus aureus, Enterococcus and Enterobacteriaceae species were 21.6, 20.3 and 7.4% respectively. MCA, and further statistical analysis, revealed that the place of residence affected the isolation frequency of years (54.9% in EPH vs. 37.9% in EPDC). Moreover, ANOVA showed that living in EPH increased the carriage of yeasts.

CONCLUSIONS

Elderly Greeks exhibit a moderate to high oral carriage of transient bacteria compared with other elderly populations. Living in EPH seems to increase both the isolation frequency and carriage of yeasts.

Cytochemical differences in bacterial glycocalyx

To examine new cytochemical aspects of the bacterial adhesion, a strain 41452/01 of the oral commensal Streptococcus sanguis and a wild strain of Staphylococcus aureus were grown with and without sucrose supplementation for 6 days. Osmiumtetraoxyde (OsO4), uranyl acetate (UA), ruthenium red (RR), cupromeronic blue (CB) staining with critical electrolytic concentrations (CECs), and the tannic acid-metal salt technique (TAMST) were applied for electron microscopy. Cytochemically, only RR-positive fimbriae in S. sanguis were visualized. By contrast, some types of fimbriae staining were observed in S. aureus glycocalyx: RR-positive, OsO4-positive, tannophilic and CB-positive with ceasing point at 0.3 M MgCl2. The CB staining with CEC, used for the first time for visualization of glycoproteins of bacterial glycocalyx, also reveals intacellular CB-positive substances-probably the monomeric molecules, that is, subunits forming the fimbriae via extracellular assembly. Thus, glycosylated components of the biofilm matrix can be reliably related to single cells. The visualization of intracellular components by CB with CEC enables clear distinction between S. aureus and other bacteria, which do not produce CB-positive substances. The small quantities of tannophilic substances found in S. aureus makes the use of TAMST for the same purpose difficult. The present work protocol enables, for the first time, a partial cytochemical differentiation of the bacterial glycocalyx.

Reassessing the presence of Candida albicans in denture-related stomatitis

OBJECTIVE

The aim of this study was to reevaluate the link between Candida albicans and denture-related stomatitis according to a modified Newton classification, which reflects the classic types of inflammation as well as the extent to which the tissue is affected.

STUDY DESIGN

Two groups of denture wearers were evaluated for denture-related stomatitis. The presence and number of yeasts on the dentures, the identification of the Candida species present, and the amount of plaque coverage were determined. Putative risk factors were included in the study. Relations between these variables and stomatitis were analyzed statistically.

RESULTS

According to Newton's classification, the presence of yeast on the denture was not linked to whether subjects had stomatitis. But with our classification, higher prevalence of yeast carriers, yeast colony number, and plaque coverage were found on the dentures of individuals with the most extensive inflammation, regardless of Newton type. Among risk factors evaluated, wearing dentures at night and smoking were associated with the most extensive inflammation. We also demonstrated that the presence of C albicans as well as the cohabitation of different Candida species was more frequent in denture-related stomatitis. The differences were statistically significant.

CONCLUSIONS

Statistical analysis of microbiologic data from different denture-related stomatitis categories according to our modified classification showed that the presence of yeast on dentures was significantly associated with the extent of the inflammation, rather than with the Newton type. Our findings suggest that the inflammatory process of stomatitis favors the colonization of Candida. These results could have new implications for diagnosis and management of the condition.

Oral microbial flora and oral malodour of the institutionalised elderly in Japan

OBJECTIVES

To determine the oral health status, especially the level of oral microbial flora and oral malodour, of institutionalised elderly people compared with non-institutionalised elderly people.

SETTING

Three institutions and numerous private homes.

SUBJECTS

56 institutionalised and 56 non-institutionalised elderly people.

MAIN OUTCOME MEASURES

Institutionalised elderly people had higher levels of candida, staphylococci, and oral malodour.

RESULTS

Institutionalised elderly people had a higher level of candida in denture wearers, and a higher level of staphylococci and oral malodour compared with the non-institutionalised elderly.

CONCLUSION

The institutionalised elderly have a higher risk of opportunistic infections and oral health care should be improved to protect them from these infections and to reduce oral malodour.

Natural defenses against Candida colonization breakdown in the oral cavities of the elderly

Candida colonization of the oral cavity increases in the elderly. A major predisposing condition is denture use, which also increases in the elderly. To test whether the increase in colonization is age-related in a fashion independent of denture use, we analyzed the frequency (incidence) of carriage, the intensity of carriage, the multiplicity of species, and the genetic relatedness of strains in the oral cavities of 93 test subjects separated into the three age groups: 60 to 69 yr, 70 to 79 yr, and > or = 80 yr. Each age group was further subdivided into subjects with and without dentures, and into males and females. The results demonstrate that the frequency of carriage, the intensity of carriage, and multispecies carriage all increase as a function of age and differ according to gender, in both cases independent of denture use, suggesting that the natural suppression of yeast carriage in the oral cavity breaks down in the elderly. In addition, it is demonstrated that Candida glabrata colonizes the oral cavities of elderly individuals without dentures only after 80 yr of age, suggesting that there are age-related compromising conditions other than denture use in this most elderly age group.

Clinical morbidity and sequelae of treatment with complete dentures

Wearing complete dentures may have adverse effects on the health of both the oral and the denture-supporting tissues. This article is a review of selected literature on the sequelae of treatment with complete dentures in the specific areas of residual ridge resorption, mucosal reactions, burning mouth syndrome, temporomandibular disorders, and patient satisfaction. Recent literature found with a Medline search from 1952 to 1996 is included in this review. Residual ridge resorption is an inevitable consequence of tooth loss and denture wearing, with no dominant causative factor having been found. Mucosal reactions have a multifactorial cause, most of which can be easily treated. Most patients are satisfied with their complete dentures. Correlations between anatomic conditions and denture quality and patient satisfaction are weak. Psychologic factors seem to be extremely important in the acceptance of and adaptation to removable dentures. There are still no reliable methods to predict the outcome of complete denture treatment and there are many problems related to treatment with complete dentures. Although the prevalence of an edentulous condition is decreasing, the great number of edentulous people warrants the continuing efforts of basic and clinical research on removable partial dentures. Complete denture prosthodontics will remain an important part of dental education and practice. In addition to clinical and technical skills, insight into patient behavior and psychology and communication techniques are also necessary.

High incidence of Staphylococcus aureus from dentures and tongues of maxillary resection patients

The incidence and virulence of Staphylococcus aureus from upper dentures and tongues of maxillary resection and edentulous patients were examined. The incidence rates of S. aureus on dentures and tongues from the 8 maxillary resection patients were significantly higher than those from the 20 maxillary edentulous patients. Some S. aureus strains in both patient groups were resistant to antibiotics, and 1 methicillin-resistant S. aureus strain was isolated in each group. Exfoliative toxin was not produced, whereas diverse types of enterotoxin were detected in 4 of the 8 maxillary resection patients and in 3 of 13 maxillary edentulous patients. These findings show that S. aureus inhabits dentures and tongues of maxillary resection patients more often than those of maxillary edentulous patients and that some strains have potential virulence, suggesting that maxillary resection patients are potentially more exposed to a threat from S. aureus and would be the carriers.

Eradication of the long-term carriage of methicillin-resistant Staphylococcus aureus in patients wearing dentures: a follow-up of 10 patients

To cure the long-term carriage of methicillin-resistant Staphylococcus aureus (MRSA), eradication treatment was given to 10 patients wearing complete dentures. In addition to multiple body sites, MRSA was cultured from the dentures of six patients. The contaminated dentures were rebased and sterilized with heat in order to prevent recolonization. The patients did not use their dentures during the decolonization therapy. Subsequently, MRSA was eradicated from three of these patients but three others remained MRSA-positive despite at least two courses of combined systemic and topical eradication treatment. These particular patients had persistent stomatitis and their dentures were a poor fit, in poor condition and repeatedly grew MRSA. Eradication treatment was successful in the remaining four patients whose dentures were MRSA-negative. These results confirm that dentures may function as foreign bodies and sustain persistent nasopharyngeal. MRSA colonization. Therefore, we suggest that whenever eradication of MRSA is deemed necessary in cases of nasal, oral or pharyngeal carriage, heat treatment of the dentures should be included. Further comparative studies with larger patient populations are needed to evaluate the contribution of dentures to the long-term carriage of MRSA, as well as to assess the value of denture sterilization during the eradication course.