Lp Samaranayake

Case report. Oro-facial manifestations of Penicillium marneffei infection in a Thai patient with AIDS

Summary. Penicillium marneffei infection is prevalent in South‐East Asia and Southern China and has been considered an acquired immunodeficiency syndrome (AIDS)‐defining disease. This report focuses on the oral and facial manifestations of P. marneffei infection in a 28‐year‐old Thai male patient with AIDS. The clinical, mycological and ultrastructural features are described.

Candida and Oral Candidosis: A Review

Candida species are the most common fungal pathogens isolated from the oral cavity. Their oral existence both as a commensal and an opportunist pathogen has intrigued clinicians and scientists for many decades, and recent investigations have revealed many attributes of this fungus contributing to its pathogenicity. In addition, the advent of the human immunodeficiency virus infection and AIDS has resulted in a resurgence of oral Candida infections. Clinicians are witnessing not only classic forms of the diseases but also newer clinical variants such as erythematous candidosis, rarely described hithertofore. Therefore, this review is an attempt at detailing the current knowledge on Candida and oral candidoses together with the newer therapeutic regimes employed in treating these mycoses.

Oral mycoses in HIV infection.

Oral mycoses in human immunodeficiency virus (HIV) infection are becoming increasingly common. Of these, oral candidiasis is by far the most prevalent; fewer than 10 cases of cryptococcosis, histoplasmosis, and geotrichosis have thus far been reported. Oral candidiasis is one of the earliest premonitory signs of HIV infection and may present as erythematous, pseudomembranous, hyperplastic, or papillary variants, or as angular cheilitis. Cumulative data from 23 surveys (incorporating 3387 adults) suggest that in general, oral candidiasis may develop in one third to half of HIV-seropositive persons. Almost equal numbers of cases manifest with either erythematous or pseudomembranous variants. These and related concepts pertaining to oral mycoses in HIV infection are reviewed.

Biofilm lifestyle of Candida: a mini review

Candida is the major fungal pathogen of humans causing a variety of afflictions ranging from superficial mucosal diseases to deep seated mycoses. Biofilm formation is a major virulence factor in the pathogenicity of Candida, and Candida biofilms are difficult to eradicate especially because of their very high antifungal resistance. Consequently, research into the pathogenicity of Candida has focused on the prevention and management of biofilm development, their architecture, and antifungal resistance. Although studies have shed some light, molecular mechanisms that govern biofilm formation and pathogenicity still await full clarification. This review outlines the key features of what is currently known of Candida biofilm development, regulation and antifungal resistance and, their proteomics.

Factors affecting the phospholipase activity of Candida species in vitro

The phospholipase activity of 41 isolates of oral Candida species was determined by a plate assay. Seventy nine per cent of the C. albicans isolates were phospholipase producers whereas none of the C. tropicalis, C. glabrata or C. parapsilosis isolates produced the enzyme. The degree of phospholipase activity (Pz value) of individual isolates was remarkably constant despite the large variation in activity among different isolates. Experiments with 10 phospholipase positive C. albicans isolates indicate that phospholipase production in vitro is limited to a narrow pH range (c. 3.6-4.7) and is suppressed by increasing concentrations of sucrose and galactose in the media (r = 0.9). Hence, candidal phospholipases seem to play a complex role in the aetiopathology of human candidoses.

Factors affecting the in-vitro adherence of Candida albicans to acrylic surfaces.

The fitting surface of the upper denture is the main reservoir of yeasts in patients with chronic atrophic candidosis. Because little is known about the adhesion of Candida albicans to acrylic surfaces, an in-vitro technique was used to investigate the effect of sucrose, glucose, lactose, xylitol, mixed and parotid saliva, serum and Streptococcus salivarius on adhesion. Enhancement of candidal adhesion was seen on serum-coated acrylic strips and by yeasts incubated in sucrose, glucose and a dialysate of Strep, salivarius. Pre-coating acrylic strips with mixed saliva, 2 per cent chlorhexidine and Strep, salivarius reduced adhesion, while pre-coating strips with 0.2 per cent chlorhexidine and parotid saliva or pre-incubating yeasts in lactose and xylitol had no significant effect on adhesion. This study suggests that the factors involved in the adhesion of C. albicans to acrylic surfaces are complex, and that they may play an important role in the aetiology of chronic atrophic candidosis.

Candida Species Exhibit Differential In Vitro Hemolytic Activities

ABSTRACT A total of 80 Candida isolates representing 14 species were examined for their respective responses to an in vitro hemolytic test. A modification of a previously described plate assay system where the yeasts are incubated on glucose (3%)-enriched sheep blood agar in a carbon dioxide (5%)-rich environment for 48 h was used to evaluate the hemolytic activity. A group of eight Candidaspecies which included Candida albicans (15 isolates),C. dubliniensis (2), C. kefyr(2), C. krusei (4), C. zeylanoides (1), C. glabrata(34), C. tropicalis (5), andC. lusitaniae (2) demonstrated both alpha and beta hemolysis at 48 h postinoculation. Only alpha hemolysis was detectable in four Candida species, viz., C. famata (3), C. guilliermondii(4), C. rugosa (1), and C. utilis (1), while C. parapsilosis (5) and C. pelliculosa (1) failed to demonstrate any hemolytic activity after incubation for 48 h or longer. This is the first study to demonstrate the variable expression profiles of hemolysins by different Candida species.

An in-vitro study of the adherence of Candida albicans to acrylic surfaces

Abstract An in-vitro system was designed to assess quantitatively the adhesion of Candida albicans to acrylic surfaces. Clear acrylic strips were placed in yeast suspensions and the number of yeasts attached per unit area was counted microscopically. A significant positive correlation was found between the concentrations of yeast in the suspension and their adhesion to the acrylic strips. Pre-incubation with sucrose greatly increased the adherence of C. albicans to the acrylic strips, and there was a direct linear increase in adhesion with increasing sucrose concentrations. The enhanced adhesion of yeasts induced by sucrose disappeared when Candida were heat-killed prior to incubation in a sucrose-containing medium. These observations, together with electron-microscopic studies, suggest that an extracellular metabolic product of the organism could be responsible for the enhanced adhesion associated with sucrose. The system can be effectively used to study the influence of other intra-oral factors on the adhesion of C. albicans to acrylic surfaces.

Oral mucosal fungal infections

This review has provided an overview of variants of oral mucosal candidiasis and current therapeutic techniques followed by an outline of the rare oral mycoses and their management. The advent of the HIV infection and the increasing prevalence of compromised individuals in the community as a consequence of surgical and medical advances have resulted in a resurgence of opportunistic infections, including oral candidiasis and other rare mycoses that were once considered exotic. It is now recognized that oral candidiasis may present in many clinical guises, including the classic white lesion of thrush as well in as nondescript, red mucosal lesions that may confound the unwary clinician. Other mycotic diseases, such as aspergillosis, cryptococcosis, histoplasmosis and mucormycosis, may manifest intra-orally, both as primary lesions and as secondary manifestations of systemic disease. Periodontal manifestations of mycotic diseases are rare. If at all, such lesions may present as erythematous areas as in linear gingival erythema and rarely as ulcerations in exotic mycoses. Most of the oral mycoses respond well to either topical or systemic therapy with the polyenes or azoles. In general, the management of oral fungal infections has been revolutionized by the triazole group of drugs, fluconazole and itraconazole, although recent reports indicate an alarming increase of resistant organisms, in particular to fluconazole.

Biofilm-Forming Ability of Candida albicans Is Unlikely To Contribute to High Levels of Oral Yeast Carriage in Cases of Human Immunodeficiency Virus Infection

ABSTRACT An increased prevalence of candidal carriage and oral candidiasis is common in cases of human immunodeficiency virus (HIV) infection, and the reasons for this may include the enhanced ability of colonizing yeasts to produce biofilms on mucosal surfaces. The aim of the present study was therefore to examine the differences, if any, in the biofilm-forming abilities of 26 Candida albicans yeast isolates from HIV-infected individuals and 20 isolates from HIV-free individuals, as this attribute of yeast isolates from patients with HIV disease has not been examined before. Biofilm formation in microtiter plate wells was quantitatively determined by both the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction method and the crystal violet method. Although candidal biofilm formation could be quantitatively evaluated by either technique, the better reproducibility (P < 0.05) of the XTT reduction assay compared with that of the crystal violet method led us to conclude that the former is more reliable. There were no significant quantitative differences in biofilm formation between C. albicans isolates from HIV-infected patients and isolates from HIV-free individuals during in vitro incubation in a multiwell culture system over a period of 66 h. Three of eight host factors in the HIV-infected group were found to be associated with candidal biofilm formation. Thus, yeasts isolated from older individuals and those with higher CD4-cell counts exhibited decreased biofilm formation, while the findings for yeasts from individuals receiving zidovudine showed the reverse (P < 0.05 for all comparison). Our data indicate that attributes other than biofilm formation may contribute to the increased oral yeast carriage rates in cases of HIV infection.