Colonization of the oral cavity by probiotic bacteria

The aim of this study was to investigate if three probiotic bacteria present in the milk product Cultura Dofilus? naturell could be detected in saliva and on oral mucosal surfaces, and if they colonized dental surfaces in situ in 8 caries-inactive individuals after 8 daily exposures to the milk product for up to 3 days. Bacteria were identified by fluorescence in situ hybridization and confocal laser scanning microscopy. While probiotic bacteria were present sporadically in the oral cavity on mucosal surfaces and in saliva after 3 days of frequent use of the probiotic milk, they were not detected on dental surfaces. Probiotic bacteria may thus contribute to general oral health, but their potential role in biofilm-induced dental diseases remains unclear.     

Implantation of Candida albicans and other Candida species in the oral cavity of rats

The carriage of five Candida species in the mouths of normal and siaioadenectomised rats was determined for periods up to 30 days after inoculation into the oral cavity. In both test and control animals. Candida albicans was the species recovered in greatest quantities at all periods, followed by C. parapsilosis and C. tropicalis. In contrast. C. gullliermondii and C. krusei were isolatable only in small numbers and only from the 1st up to the 5th day; they were not present thereafter. Sialoadenectomy favoured oral colonisation only by C. albicans ( P <0.05) and did not influence the carriage of the other species.     

Improved oral hygiene and Candida species colonization level in geriatric patients

OBJECTIVES: This work consists in improving oral hygiene (OH) for elderly dependent people in long-term hospital care, in order to decrease the degree of colonization and the associated risk of developing oral candidiasis. As this population frequently suffers from such colonization and because it is difficult to install and practice OH care, a study protocol was designed at the request of geriatricians. The objective of the present study was to set up a programme of OH, applied by the care staff, and to monitor oral colonization of by Candida spp. BASIC RESEARCH DESIGN: We compared the levels of hygiene and Candida spp. colonization for a group of 110 long-term patients in geriatric departments at T1, when clinical data were collected and oral mycological samples taken before the OH protocol was applied, and at T2, during the postprotocol phase after 3 months of application, when the clinical data and sample collection were repeated. RESULTS: During these 3 months 11 patients died. These patients were excluded from the results, which are presented for matched series of the 99 patients still present at T2. Statistical analysis comparing the clinical and biological parameters at T1 and T2 established that there had been an improvement in OH: the 'adequate' level was reached for 72.4% of patients at T2 compared with 41.8% at T1 (P < 0.001) and the 'very inadequate' level was observed for 9.2% at T2 compared with 27.9% at T1 (P < 0.01). A reduction was observed in the number of patients showing the highest degree of C. albicans and C. glabrata colonization (> 50 colony forming units) from 41.9% at T1 to 24.9% at T2 (P < 0.05) and from 56.4% at T1 to 13.0% at T2 (P < 0.05) respectively. The number of patients with candidiasis fell significantly from 43.2% at T1 to 10.2% at T2. CONCLUSIONS: The OH protocol led to an overall decrease in Candida spp. colonization, a significant reduction in the number of candidiasis and an improvement in the level of oral and denture hygiene but vigilance is still necessary concerning OH care and the initial training of staff in specific care of the mouth.     

Colonization of the oral cavity of mice by an unidentified streptococcus

While studying the oral bacterial biota of mice, we observed an unidentified streptococcus (TG) that eventually became the dominant species of the oral cavities of all other mice in our animal facility. We found that the strain is indigenous to Jackson Laboratory mice but is absent in animals from Charles River Laboratories. TG was also transmitted from artificially contaminated BALB/c mice to the oral cavities of 4 other mouse strains. Streptococcus sp. TG stimulated the secretory and systemic immune systems of artificially contaminated Charles River BALB/c mice but did not provoke clinical symptoms. The increase in antibody level to TG did not prevent its colonization and persistence in these mice. In mice from Jackson Laboratory, the secretory and systemic immune response to TG was significantly lower. In vitro , Streptococcus sp. TG inhibited murine oral lacto-bacilli and staphylococci, probably due to the production of hydrogen peroxide.     

Colonization of Lactobacillus rhamnosus GG in the oral cavity

BACKGROUND/AIMS: Lactobacillus rhamnosus GG (LGG) is one of the most widely studied probiotic bacterial strain. The benefits of LGG treatment in gastrointestinal disorders are well documented. The aim of the present study was to investigate whether LGG can be detected in the oral cavity after discontinuation of administration of a product prepared with this bacterium. MATERIAL AND METHODS: 56 volunteers consumed Gefilus juice (Valio Ltd, Helsinki, Finland) containing LGG during a 14-day trial period. Saliva samples were collected and cultured onto MRS agar after a clearance period and then daily after a 2-week intervention period for as long as LGG was found. LGG-like colonies were analyzed in saliva samples, identified by characteristic colony morphology, a lactose fermentation test, and PCR with specific primers. RESULTS: LGG was not able to colonize the oral cavity. It could only be temporarily detected. In one female subject, however, whose medical history revealed use of LGG in childhood, the bacterium was detected in all saliva samples taken up to 5 months. (She was excluded from the intervention trial). CONCLUSION: Permanent colonization of LGG in the oral cavity is improbable but seems possible in individual cases.     

Carriage of Candida species in the oral cavity in diabetic patients: relationship to glycaemic control

To study the possible relationship between the quality of glycaemic control in diabetes mellitus and the carriage of Candida species, the Candidal carrier status of 412 diabetic patients was examined using an oral rinse technique and correlated with measurements of random blood glucose and total glycosylated haemoglobin. Candida was isolated in 210 diabetics (51%) with 13 patients (6%) carrying more than one species. The positive isolates were: Candida albicans (89%), Candida krusei (2.8%), Candida glabrata (2.8%), Candida tropicalis (6.2%), Candida stellatoidea (2.8%) and Candida parapsilosis (0.5%). No association was identified between carriage rates and the type of treatment of diabetes, or with the quality of glycaemic control. As in non-diabetic subjects, the carriage rates were higher in diabetic patients wearing dentures. Thus, the oral carriage of Candida in diabetic patients was independent of glycaemic control but in certain sub-groups the carriage rates were higher, and involved uncommon candidal species.     

Carriage of Candida species in the oral cavity in diabetic patients: relationship to glycaemic control

To study the possible relationship between the quality of glycaemic control in diabetes mellitus and the carriage of Candida species, the candidal carrier status of 412 diabetic patients was examined using an oral rinse technique and correlated with measurements of random blood glucose and total glycosylated haemoglobin. Candida was isolated in 210 diabetics (51%) with 13 patients (6%) carrying more than one species. The positive isolates were: Candida albicans (89%), Candida krusei (2.8%), Candida glabrata (2.8%), Candida tropicalis (6.2%), Candida stellatoidea (2.8%) and Candida parapsilosis (0.5%). No association was identified between carriage rates and the type of treatment of diabetes, or with the quality of glycaemic control. As in non-diabetic subjects, the carriage rates were higher in diabetic patients wearing dentures. Thus, the oral carriage of Candida in diabetic patients was independent of glycaemic control but in certain sub-groups the carriage rates were higher, and involved uncommon candidal species.     

Colonization of the human oral cavity by a strain of Streptococcus mutans

Streptococcus mutans strain JH1001 produces a bacteriocin that can kill virtually all other strains of this micro-organism. The ability of JH1001 to colonize the human oral cavity was tested in a study involving five subjects and three different infection regimens, all of which involved multiple exposures to large numbers of organisms. Two and one-half years after infection, JH1001 was found to have persistently colonized three of the subjects. The indigenous S. mutans in one subject were reduced below the level of detection. Levels of (total) S. mutans and S. sanguis were not affected in persistently colonized subjects. Mutants of indigenous S. mutans resistant to the bacteriocin were not observed. The results indicate the importance of host variability and infection regimen for superinfection by this strain of S. mutans. The efficient replacement of indigenous S. mutans by JH1001 in one subject lends support to the eventual application of replacement therapy to the prevention of dental caries.     

Isolation of Candida species from the oral cavity and fingertips of complete denture wearers.

STATEMENT OF PROBLEM: Candida species usually colonize in the oral cavity of denture wearers and may also colonize on their fingers because of frequent manual manipulation of the dentures. PURPOSE: This study investigated the association between oral and fingertip candidal isolation in a group of denture wearers. MATERIAL AND METHODS: Oral rinse and fingerprints obtained from 25 healthy male complete denture wearers were microbiologically investigated for candidal growth, and isolated Candida species were identified with a germ tube test and a commercially available yeast identification system. Denture cleanliness, hand washing, and denture wearing and handling habits were recorded for each subject. RESULTS: Candida species were isolated from the oral cavity of 15 (60%) and fingertips of 11 (44%) subjects. Ten (66.7%) subjects had concomitant oral and fingertip candidal isolation, whereas 5 (33.3%) subjects had only oral Candida (P=.005). CONCLUSION: The hands of denture wearers who had oral Candida were significantly more colonized with Candida species than oral Candida-free subjects. Further studies identifying Candida species to the strain level and the significance of hand Candida as a source for mouth reinfection are needed.     

Colonization of the human oral cavity by a Streptococcus mutans mutant producing increased bacteriocin

Streptococcus mutans strain JH1005 is a mutant that produces levels of bacteriocin activity three-fold-elevated than those produced by its parent, JH1001. A single infection regimen with JH1005 was found to result in persistent colonization of the teeth of all three adult subjects tested. This is a significant improvement over JH1001, which required multiple exposures in order to colonize the teeth of humans reliably. The levels of total cultivable bacteria and indigenous S. sanguis were not affected by JH1005 colonization. In two of the three subjects, total (indigenous plus JH1005) S. mutans levels were significantly decreased. The results provide additional support for the role of bacteriocin production as an ecological determinant in colonization by S. mutans. They also indicate that a practical regimen for infection by an effector strain might be achieved for use in the replacement therapy of dental caries.     

Isolation and identification of Candida from the oral cavity

A number of methods of sampling the oral cavity for the presence of candida have been developed. Such techniques play an important role in the diagnosis and management of oral candidosis. In the past, identification of candida isolated from the oral cavity has usually been limited to the genus Candida or to the species C. albicans. However, with the recognition that Candida species differ in the production of putative virulence factors and sensitivity to antifungal agents, greater emphasis has been placed on identification of isolates to species level. As a result a range of commercially available systems for yeast identification can now be used in conjunction with traditional identification procedures.     

Biofilm formation by oral clinical isolates of Candida species

We have conducted a longitudinal study to quantify biofilms in oral clinical isolates of Candida species (spp.) from adults with local and systemic predisposing factors for candidiasis. A total of 69 yeast isolates from 63 Mexican patients were evaluated. These isolates (39 C. albicans, 15 C. tropicalis, 7 C. glabrata, 4 C. krusei, 1 C. lusitaniae, 1 C. kefyr, 1 C. guilliermondii and 1 C. pulcherrima) were obtained from two clinical sites: 62.3% (n = 43) from the oral mucosa of totally and partially edentulous patients, and 37.7% (n = 26) from the oral mucosa of diabetics. In addition, Candida ATCC strains were used as controls for each experiment. The kinetics of biofilm formation were measured by 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide [XTT] reduction; each isolate was tested at 6, 12 and 24 h. Biofilm formation is dependent on the Candida spp. and its clinical origin. On average, the oral isolates of C. glabrata are strong biofilm producers, whereas C. albicans and C. tropicalis are moderate producers. The most common species in our population was C. albicans. While the kinetics of C. albicans biofilm formation varies between oral isolates, it generally maintains steady growth from 2 to 48 h, when it reaches its maximum growth.     

A strip test for detecting Candida in the oral cavity.

One-hundred and twenty persons were screened for the presence of Candida in the mouth. Salivary samples were cultured on Sabouraud's agar, on yeast extract, and on Microstix. Microstix is a new and simple method testing for Candida. The reliability of the strip for detecting clinically identified candidiasis in severely ill patients was 100 per cent. Of ninety-three clinically healthy controls, forty-five were found to be Candida carriers according to the two conventional methods (Sabouraud's agar and yeast extract), but only forty-one of them by the strip. The discrepancy might be explained by the limit of the sensitivity of the strip (5.10(2) yeast per milliliter). The strip is recommended for testing clinically suspected candidiasis and is very useful for screening.     

HPV and other risk factors of oral cavity/oropharyngeal cancer in the Czech Republic

OBJECTIVE: An association between high-risk human papillomavirus (HR HPV) infection and a risk of development of a subgroup of head and neck cancers has been proposed recently. The main risk factors of oral and oropharyngal cancer observed in our population are smoking and alcohol consumption. The incidence of oral/oropharyngeal tumours in the Czech Republic is relatively high and there are no data available about the prevalence of HPV DNA presence in these tumours. MATERIALS AND METHODS: Eighty patients with a primary oropharyngeal cancer were enrolled. The presence of HPV DNA has been evaluated by polymerase chain reaction in 68 cases from which the tumour tissue and demographical and clinical data were available. The typing of HPV was performed by nucleotide DNA sequencing. RESULTS: The HPV DNA was detected in 51.5% of samples tested. Among the HPV DNA positive tumours, 80% contained HPV16. In the analysed group there were 54 men and 14 women. The prevalence of HPV DNA was lower in oral (25%) than in oropharyngeal (57%) tumours, and higher in never smokers (100%) and never drinkers (68.8%). HPV DNA presence was not related to gender, age, number of lifetime sexual partners or practice of oral-genital sex, size of tumour or presence of regional metastases. CONCLUSIONS: The difference in the prevalence of HPV DNA positive tumours between cases of oral cavity and oropharyngeal carcinoma exposed and not exposed to tobacco or alcohol support the theory that HPV DNA positive tumours form an aetiologically distinct subgroup of head and neck tumours.     

Conflicting priorities: oral health in long-term care

Open-ended interviews were conducted with 109 individuals. These included: administrators, staff, dental personnel, residents, and family members, associated with 12 long-term-care (LTC) facilities to contrast different human resource and organizational strategies for managing the delivery of oral health care to the elderly residents. A multiple case-study analysis revealed that no particular organizational strategy was ideal, although three important components—oral hygiene, diagnostic assessments, and dental treatment—were common to all. The dental personnel everywhere believed that oral health in the midst of other conflicting priorities received inadequate attention, while the administrators and staff acknowledged that they were weak at recognizing oral disorders and assisting with oral hygiene. In all, the interviews offered a portrait of the conflicting priorities associated with LTC, and they provide practical insights to successful strategies of care in this population .