Biomedical subjects
Publications and source records attributed to L P Samaranayake.
A case of a dento-alveolar abscess due to a polymicrobial infection with a yeast, Candida guilliermondii and two other oral bacteria are described. A review of the literature has revealed only a single case of an odontogenic abscess due to Candida species and we believe this to be the first report of a dentoalveolar infection where Candida guilliermondii is associated as a co-pathogen.
This study investigated whether oral candida infection in diabetics and adhesion of Candida albicans to buccal epithelial cells in vitro were related. Buccal cells from 50 patients with diabetes mellitus showed a significant increase in adhesion of C. albicans strain CDS 88 compared with those collected from 50 non-diabetic controls matched for age, sex and denture status. Oral candida carriage, candida infection and secretor status were also investigated in both groups. The frequency of carriage was increased, but not significantly, and there was a significantly higher incidence of candida infection in diabetic patients compared with controls. Diabetic patients who were non-secretors had a significantly increased frequency of oral candida carriage.
An in vitro bacterial adherence assay which employed human tooth enamel sections precoated with saliva and an epifluorescent staining technique with acridine orange was developed. The assay was used to study the adherence properties of fresh and type strains of the following oral bacterial species: Bacteroides gingivalis, Bacteroides intermedius, Capnocytophaga species, Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Peptostreptococcus species, Veillonella species, Actinomyces israelii, Streptococcus salivarius and Streptococcus sanguis. Approximately half of the bacteria tested adhered well to enamel, including the fresh isolates of B. gingivalis, B. intermedius, Veillonella species and S. sanguis. Adherence did not correlate in all cases with the known distribution of these species in vivo. Three-quarters of the fresh strains adhered better than the type strains of the same species. The assay method is an alternative to the widely used hydroxyapatite bead assay.
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A transcultural comparison of the attitudes of hospital dental practitioners and final year dental students in Glasgow, Scotland and Los Angeles, USA was made to assess their attitudes towards treatment of AIDS and hepatitis B patients. Almost all of the respondents were aware of the facts related to spread of AIDS via saliva and blood and the major oral manifestations of AIDS. Surprisingly, a significant proportion of respondents in both countries said they will not attend their dentist if the latter treats AIDS patients and significantly more Americans thought that AIDS transmission was likely in the dental clinic. An overwhelming majority thought specially trained dentists should be employed to treat AIDS patients while the majority of Americans, as compared with Scots surmised that AIDS is a serious threat to public health. In general, the attitudes of the two survey populations towards the AIDS epidemic and attendant problems was similar although the Scots were more complacent than their American counterparts, probably due to the less immediacy of the AIDS problem in Scotland.
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The oral carriage of Candida species and coliforms in a healthy adult population and a group of patients with burning mouth syndrome (BMS) was investigated. The intra-oral prevalence of Candida species and coliforms was higher in the BMS group compared with the controls. The most frequent yeast isolated from the BMS group was Candida albicans while Enterobacter and Klebsiella species were the most prevalent coliforms. The possible reasons and the significance of the above findings are discussed.
A postal survey of 730 Malaysian dental practitioners was undertaken to assess their awareness and acceptance of the plasma derived hepatitis B vaccine. Only 32% of the 325 practitioners who responded had been vaccinated, 41% intended to be and 15% categorically refused vaccination. The main reservations about vaccine acceptance were fear of side effects including AIDS, cost of the vaccine and lack of information. Vaccine efficacy was not confirmed by serology in two-thirds of the vaccinees and two-fifths of the respondents were unaware that 5% of the vaccinees do not develop a successful antibody response after vaccination. Seventy-eight percent of dentists believed that their risk of contracting hepatitis B was high or very high while 71% recalled having received needle stick injuries in the 3 yr prior to the survey. Only 13% of respondents were aware of delta hepatitis while 63% were aware of non-A non-B hepatitis. The survey has highlighted the need for dissemination of information on hepatitis B vaccine among dentists in Malayasia.
The association of oral candidiasis with the human immunodeficiency virus (HIV) infection has been known since the advent of the acquired immunodeficiency syndrome (AIDS) pandemic. Oral candidiasis is one of the earliest premonitory signs of HIV infection and its diagnosis may have grave prognostic implications for the eventual development of full blown AIDS. There is now an expanding body of data on novel clinical variants of this 'old' disease, its epidemiology in HIV seropositive individuals and, advances in its management, particularly with respect to the recently introduced bis-triazole antifungals. Current concepts pertaining to the epidemiology, clinical features, pathogenesis, laboratory diagnosis and management of oral candidiasis in HIV infection are reviewed.
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Exfoliated buccal epithelial cells have been widely used in microbial adherence studies, but present a number of problems due to their variable nature and to contamination with indigenous bacteria. An adherence assay was developed using HeLa cell monolayers which were washed with buffer, or treated with saliva or serum to mimic buccal or crevicular epithelial cells, respectively. A total of eighteen strains of oral bacteria tested showed a low affinity for untreated HeLa cells, but most strains adhered in high numbers to saliva treated HeLa cells. A few strains, usually present in the gingival crevice, demonstrated a high affinity for serum treated HeLa cells. Thus, salivary and crevicular fluid components appear to be specifically implicated in the selective adherence and colonization of bacteria on oral surfaces.
Infection with the human immunodeficiency virus (HIV), the aetiologic agent of AIDS has emerged as the medicine's modern scourge of mankind. Despite the millions of pounds and dollars spent on conquering the disease, it is spreading globally and millions are thought to be currently infected. There is, therefore, little doubt that a large number of dental practitioners have either knowingly or unknowingly treated HIV infected individuals and they will continue to do so in the future. Therefore, all dental personnel should be aware of the epidemiology and clinical manifestations of the disease and the implications for clinical dentistry. This update is an attempt to review the expanding body of data on HIV infection and AIDS, particularly in relation to dentistry.
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The adherence of six Candida species to fibrin clots was studied using a simple, in vitro technique. Yeast suspensions were incubated with fibrin clots and the number of adherent organisms quantified as follows: after washing, the clots were subjected to vortex mixing and the number of CFU's which subsequently grew on Sabourauds medium were counted. Adhesion was directly proportional to the concentration of Candida species in the suspension (r = 0.99 p less than 0.001). C. albicans and C. tropicalis exhibited marked adherence whereas C. krusei, C. gulliermondi and C. glabrata adhered less readily. C. parapsilosis was intermediate in its ability to adhere.
A variety of mouthwashes are frequently used in the management of irradiation-induced mucositis. Benzydamine has recently been introduced for alleviating this condition. Its efficacy as a mouthwash was compared with chlorhexidine in two groups of patients receiving radiotherapy for oral carcinoma. Mucositis and pain were recorded over a 6 week period and oral carriage of Candida species, coliforms and Staphylococcus aureus was assessed using an oral rinse technique. There was no significant difference in the mucositis scores, overall pain scores or the yeast and bacterial species isolated between the two treatment groups. However, 58% (7 out of 12) and 92% (12 out of 13) patients reported oral discomfort when rinsing the mouth with chlorhexidine and benzydamine, respectively. In both groups, the most common coliform isolated was Klebsiella pneumoniae and the carriage of yeasts was significantly greater than that of coliforms. These results indicate that, although the individual patient acceptance of chlorhexidine is better than benzydamine, there is little difference between the two mouthwashes both in controlling pain and mucositis or in the oral carriage of the micro-organisms studied.
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