Species Distribution and Antifungal Susceptibility Profile of Oral Candida Isolates from HIV-infected Patients in the Antiretroviral Therapy Era

Molecular identification and antifungal susceptibility pattern of Candida species isolated from HIV infected Patients with candisiasis

Background and Purpose:

Opportunistic fungal infections have been on a growing trend since the last two decades. Among the opportunistic fungal agents, Candida species, Cryptococcus neoformans, and Aspergillus fumigatus account for most of the life-threatening infections in immunocompromised individuals. Regarding this, the present study aimed to investigate the molecular identification and antifungal susceptibility pattern of Candida species isolated from HIV-infected patients.

Materials and Methods:

This study was conducted on 80 clinical samples collected from HIV-infected patients with suspected candidiasis referring to Tagore Medical College and Hospital, Rathinamangalam and Government Hospital of Thoracic Medicine, in Chennai, India, for 18 months (i.e., May 2016-December 2017). Phenotypic and molecular identification was accomplished using internal transcribed spacer region 1 (ITS1) and ITS4 primers. The antifungal susceptibility pattern of the isolates against four antifungal agents was also determined by both disk diffusion and broth dilution methods.

Results:

In the present study, the prevalence of candidiasis was obtained as 75% (n=60). Candida tropicalis was the predominant identified species. All the emerging species (i.e., Kodamaea ohmeri, Hanseniaspora opuntiae, and C. orthopsilosis) were identified through molecular identification since the phenotypic identification was inconclusive. In terms of the susceptibility pattern, 63.3% and 18.3% of the isolates were resistant to fluconazole and voriconazole, respectively. Candida albicans was also found to be resistant to amphotericin B.

Conclusion:

Molecular assay led to the identification of K. ohmeri, H. opuntiae, and C. orthopsilosis, which were multidrug-resistant. This study highlighted the need for the prompt and timely identification of clinical yeast isolates given the emergence of many rare species and their capability of causing life-threatening infections and outbreaks. In the laboratories where molecular diagnostic methods are not available, alternative services of reference laboratories can be utilized as cost-effective measures. With regard to the growing prevalence of antifungal drug resistance, antifungal susceptibility testing should be made mandatory for effective patient management.

Etiologic Agents and Antifungal Susceptibility of Oral Candidosis from Romanian patients with HIV-infection or type 1 diabetes mellitus

This is the first Romanian investigation of oral candidosis in patients suffering of HIV-infection or type 1 diabetes mellitus (T1DM). Candida albicans was the dominant species in both types of isolates: n = 14 (46.7%) in T1DM, n = 60 (69.8%) in HIV. The most frequent non-albicans Candida spp. were Candida kefyr (n = 6; 20%) in T1DM and Candida dubliniensis (n = 8; 9.3%) in HIV. Resistance to fluconazole was detected only in the HIV non-albicans Candida group (n = 8; 9.3%). All isolates were susceptible to VOR. The experimental drug MXP had MIC values equal or close to the ones of VOR. Echinocandin resistance was more frequent than azole resistance.

Antimicrobial activity of complete denture cleanser solutions based on sodium hypochlorite and Ricinus communis - a randomized clinical study

To preserve oral health and to maintain the prosthetic devices, it is important not only to improve the properties of commonly known hygiene products, but also to investigate new materials with antimicrobial action.

Candida Species Prevalence Profile in HIV Seropositive Patients from a Major Tertiary Care Hospital in New Delhi, India

Candida is a common opportunistic pathogen during the course of human immunodeficiency virus (HIV) disease progression. Changes in the clinical severity of candidiasis and the Candida species prevalence profile may be a reflection of immunological changes in HIV positive patients. The aim of this study was to document the changing pattern of Candida species prevalence profile in HIV seropositive patients from a tertiary care hospital in North India. One hundred and twenty HIV seropositive subjects were recruited for Candida microbial screening. Clinical specimens including blood, oral swabs, expectorated or induced sputum/bronchoalveolar lavage specimens, and urine were collected depending on the patient's symptoms. A total of 128 Candida isolates were obtained from 88 cases and 7 different Candida species were identified. C. albicans (50%) was the most common species isolated followed by C. glabrata (17%) and C. dubliniensis (12.5%). Other species isolated were C. parapsilosis (7.8%), C. krusei, C. tropicalis (4.6% each), and C. kefyr (3%). Strong clinical suspicion along with optimal sampling of an accurate diagnosis of Candida species involved would go a long way in decreasing the morbidity associated with non-albicans Candida species.

Prevalence of oral Candida colonization in patients with diabetes mellitus

OBJECTIVES OF THE STUDY

We aimed to assess the prevalence of oral Candida colonization in patients with diabetes and its relationship with factors such as Candida species, serum glucose level, and the susceptibility rate of isolated yeasts to antifungals.

PATIENTS

Random samples were obtained from 113 patients with type 2 diabetes, 24 patients with type 1 diabetes, and 105 healthy controls.

MATERIALS AND METHODS

The samples were taken by swabbing the oral mucosa of patients with diabetes mellitus and healthy individuals. Afterwards the samples were inoculated onto CHROMagar-Candida. The growing colonies were counted, and the isolated yeasts were identified by PCR-RFLP and RapID methods. Various isolated species of Candida were also subjected to susceptibility testing of antibiotic drugs. Blood samples were taken to evaluate glycosylated hemoglobin (HbA1c).

RESULTS

Although the Candida carriage rate and density were statistically higher in diabetics than healthy individuals, no direct association was found between having high Candida-burden and glycosylated hemoglobin. The most commonly isolated species in both diabetics and controls was Candida albicans. Of the tested antifungal drugs, the highest rate of resistance was found against itraconazole, followed in frequency by ketoconazole and fluconazole.

CONCLUSIONS

This study identified a significant association between the poor glycemic control and the higher prevalence rates of Candida carriage and density in diabetic patients. In addition, a high prevalence of C. dubliniensis in diabetic patients was found, which might be misdiagnosed with its morphologically related species, C. albicans.

Spectrum and the In Vitro Antifungal Susceptibility Pattern of Yeast Isolates in Ethiopian HIV Patients with Oropharyngeal Candidiasis

Background. In Ethiopia, little is known regarding the distribution and the in vitro antifungal susceptibility profile of yeasts. Objective. This study was undertaken to determine the spectrum and the in vitro antifungal susceptibility pattern of yeasts isolated from HIV infected patients with OPC. Method. Oral pharyngeal swabs taken from oral lesions of study subjects were inoculated onto Sabouraud Dextrose Agar. Yeasts were identified by employing conventional test procedures and the susceptibility of yeasts to antifungal agents was evaluated by disk diffusion assay method. Result. One hundred and fifty-five yeast isolates were recovered of which 91 isolates were from patients that were not under HAART and 64 were from patients that were under HAART. C. albicans was the most frequently isolated species followed by C. glabrata, C. tropicalis, C. krusei, C. kefyr, Cryptococcus laurentii, and Rhodotorula species. Irrespective of yeasts isolated and identified, 5.8%, 5.8%, 12.3%, 8.4%, 0.6%, and 1.3% of the isolates were resistant to amphotericin B, clotrimazole, fluconazole, ketoconazole, miconazole, and nystatin, respectively. Conclusion. Yeast colonization rate of 69.2% and 31% resistance to six antifungal agents was documented. These highlight the need for nationwide study on the epidemiology of OPC and resistance to antifungal drugs.

Antifungal Susceptibility Testing with Etest for Candida Species Isolated from Patients with Oral Candidiasis

Background

The necessity of performing antifungal susceptibility tests is recently increasing because of frequent cases of oral candidiasis caused by antifungal-resistant Candida species. The Etest (BioMerieux, Marcy l'Etoile, France) is a rapid and easy-to-perform in vitro antifungal susceptibility test.

Objective

The purpose of this study was to determine the minimal inhibitory concentrations (MICs) of antifungal agents by using the Etest for Candida species isolated from patients with oral candidiasis.

Methods

Forty-seven clinical isolates of Candida species (39 isolates of Candida albicans, 5 isolates of C. glabrata, and 3 isolates of C. tropicalis) were tested along with a reference strain (C. albicans ATCC 90028). The MIC end points of the Etest for fluconazole, itraconazole, voriconazole, and amphotericin B susceptibility were read after the 24-hour incubation of each isolate on RPMI 1640 agar.

Results

All Candida isolates were found susceptible to voriconazole and amphotericin B. However, all five isolates of C. glabrata were resistant to itraconazole, among which two isolates were also resistant to fluconazole.

Conclusion

This study revealed that the Etest represented a simple and efficacious method for antifungal susceptibility testing of Candida species isolated from oral candidiasis patients. Therefore, voriconazole and amphotericin B should be recommended as effective alternatives for the treatment of oral candidiasis.

Dynamic analysis of oral Candida carriage, distribution, and antifungal susceptibility in HIV-infected patients during the first year of highly active antiretroviral therapy in Guangxi, China

BACKGROUND

Highly active antiretroviral therapy (HAART) as an effective therapy for immune reconstruction among patients with HIV/AIDS might have influence on oral Candida status. We investigated oral Candida carriage, distribution, and antifungal susceptibility dynamically during the first year of HAART among adult HIV-infected patients in Guangxi, China.

METHODS

Forty-five adult HIV-infected patients who received their first year HAART in the AIDS clinic of the Guangxi Center for Disease Control (CDC) and 31 healthy individuals were recruited. Clinical information and oral examinations were obtained. Oral rinses taken from patients at baseline, 3, 6, 12 months during HAART, respectively, were cultured, and Candida species were identified following standard microbiological techniques. In vitro antifungal susceptibilities were tested by the broth microdilution method.

RESULTS

The oral Candida load decreased gradually in the 45 patients with HIV/AIDS during the first year of HAART (P < 0.050). Among 176 Candida isolates, Candida albicans (114/176) was the predominant species, and Candida parapsilosis (23/62) was the most common non-albicans species. We found the frequency of resistance to fluconazole and itraconazole of Candida isolated from our samples increased (P < 0.05) after 12 months of HAART. In addition, the frequency of C. albicans isolates resistant to fluconazole and itraconazole was on the rise (P < 0.05).

CONCLUSIONS

The Candida load decreased with increased CD4(+) T cell counts, and C. albicans was still the prevailing species. Further, a trend toward more frequent in vitro resistance to fluconazole and itraconazole was observed. Our results provide reference for treatment and prevention of oral candidiasis among this population.

Yeast oropharyngeal colonization in human immunodeficiency virus-infected patients in central taiwan

A prospective, cross-sectional study was conducted at a medical center in central Taiwan to understand the prevalence, associated factors, and microbiologic features for oropharyngeal yeast colonization in human immunodeficiency virus-infected outpatients. Oral yeast colonization was detected in 127 (45 %) patients, including 21 (16.5 %) colonized by more than one species. Of the 154 isolates, Candida albicans was the most common species (114, 74 %), followed by Candida dubliniensis (10, 6.5 %), Candida glabrata (10, 6.5 %), Candida tropicalis (7, 4.5 %), and 13 others. We found that receiving antituberculous drug (p = 0.046) or atazanavir (p = 0.045) was two predictors for patients colonized by non-C. albicans species (p = 0.005) and risking mixed yeast colonization (p = 0.009). Even though our data showed that clinical antifungal drugs remained effective in vitro against the colonizing yeasts, the increased mixed yeast colonization indicates a potential issue for controlling mixed infections in hospital settings.

Susceptibility profile of a Brazilian yeast stock collection of Candida species isolated from subjects with Candida-associated denture stomatitis with or without diabetes

OBJECTIVE

This study investigated the susceptibility of 198 clinical isolates of Candida species against caspofungin, amphotericin B, itraconazole, and fluconazole.

STUDY DESIGN

Suspensions of the microorganisms were spread on Roswell Park Memorial Institute (RPMI) agar plates. Etest strips were placed on the plates, and the minimal inhibitory concentration (MIC) was read after incubation (48 h at 37 °C). Data were analyzed by a factorial analysis of variance and a 2 × 2 post hoc test (α = .05).

RESULTS

C glabrata showed the highest MIC values (P < .001) against caspofungin, itraconazole, and fluconazole. For amphotericin B, the MIC values of C tropicalis and C glabrata (P = .0521) were higher than those of C albicans (P < .001). Itraconazole was the least effective antifungal; 93.3% of the C glabrata isolates, 3.3% of the C albicans, and 1.3% of the C tropicalis were resistant. All microorganisms were susceptible to caspofungin and amphotericin B.

CONCLUSIONS

Caspofungin and amphotericin B should be recommended as an effective alternative for the management of oral Candida infections when treatment with topical or other systemic drugs has definitely failed.

Asymptomatic oral yeast carriage and antifungal susceptibility profile of HIV-infected patients in Kunming, Yunnan Province of China

BACKGROUND

Oral Candida colonization and its relation with predisposing factors in HIV-infected patients have received wide concerns during recent decades. In this study, we investigated asymptomatic oral Candida carriage rate, species distribution and antifungal susceptibility of 604 HIV-infected patients and 851 healthy individuals in Kunming, Yunnan Province of China.

METHODS

Mucosal swab sampling was taken from each subject and CHROMagar Candida agar medium and API 20C AUX system were used to identify yeast isolates. In vitro antifungal susceptibility was tested by the broth microdilution method according to the M27-A2 document of the Clinical and Laboratory Standard Institute (CLSI).

RESULTS

The oral yeast colonization rate in HIV-infected patients (49.5%) was higher than that of healthy subjects (20.7%). Candida albicans constituted the most frequent species, accounting for 82.2% of yeast isolates. The remaining species were composed of C. glabrata, C. parapsilosis, C. krusei, C. tropicalis, C. rugosa, C. norvegensis, Pichia ohmeri and Saccharomyces cerevisiae. In HIV-infected patients, asymptomatic oral yeast colonization was associated with low CD4 cell count (<200 cells/mm3) and lack of highly active antiretroviral therapy (HAART). Different Candida species isolated from our samples presented different susceptibility to voriconazole, fluconazole and itraconazole. Amphotericin B had the best inhibiting effect for all isolates.

CONCLUSION

Oral yeast colonization in Han Chinese patients with HIV from Kunming had common and unique features and was associated with CD4 cell number and HARRT. Amphotericin B should be used with first priority in controlling Candida infection in Han Chinese patients from Kunming. Our results provide first hand information on monitoring oral yeasts colonization in HIV-infected patients from Kunming, China.

Effects of probiotic bacteria on Candida presence and IgA anti-Candida in the oral cavity of elderly

Imbalance in the resident microbiota may promote the growth of opportunistic microorganisms, such as yeasts of Candida genus and the development of diseases, especially in aged people. This study evaluated whether the consumption of the probiotic Yakult LB® (Lactobacillus casei and Bifidobacterium breve) was able to influence on the specific immunological response against Candida and on the presence of these yeasts in the oral cavity of 42 healthy aged individuals. Saliva samples were collected before and after the probiotic use for 30 days, 3 times a week. The samples were plated in Dextrose Saboraud Agar with chloramphenicol, the colony-forming units (CFU/mL) were counted and the Candida species were identified. Anti-Candida IgA analysis was conducted using the ELISA technique. ANOVA and Student's t-test were used for normally distributed data and the Wilcoxon test was used for data with non-normal distribution (α=0.05). The results showed a statistically significant reduction (p<0.05) in Candida prevalence (from 92.9% to 85.7%), in CFU/mL counts of Candida and in the number of non-albicans species after consumption of the probiotic. Immunological analysis demonstrated a significant increase (p<0.05) in anti-Candida IgA levels. In conclusion, probiotic bacteria reduced Candida numbers in the oral cavity of the elderly and increased specific secretory immune response against these yeasts, suggesting its possible use in controlling oral candidosis.

Predisposing factors for oropharyngeal colonization of yeasts in human immunodeficiency virus-infected patients: a prospective cross-sectional study

BACKGROUND

Oropharyngeal candidiasis continues to be a major opportunistic infection in human immunodeficiency virus (HIV)-infected patients. The objectives of this study were to investigate the prevalence, associated factors, and microbiologic features for oropharyngeal yeast colonization in HIV-infected patients.

METHODS

From October to December 2009, consecutive HIV-infected patients older than 18 years were recruited in this study. Demographic information, underlying conditions, and clinical histories were collected. Oropharyngeal swab cultures for yeasts and antifungal drug susceptibilities of the isolates were performed.

RESULTS

Of the 105 HIV-infected patients, 54 (51.4%) were colonized with yeasts, including 11 patients (20.4%) with more than one species. Among the 68 isolates, Candida albicans accounted for 73.5%, followed by Candida tropicalis (5.9%), Candida glabrata (5.9%), and Candida dubliniensis (4.4%). There were 7.5% and 6% Candida isolates resistant to fluconazole and voriconazole, respectively. All of the Candida isolates were susceptible to amphotericin B. A higher prevalence of yeast colonization was noted in patients with a CD4 cell count ≤200 cells/μL (p = 0.032). Multivariate regression analysis showed that intravenous drug use was an independent associated factor for oropharyngeal yeast colonization (odds ratio, 5.35; 95% confidence interval, 1.39-20.6; p = 0.015), as well as protease inhibitor-containing antiretroviral therapy (odds ratio, 3.59; 95% confidence interval, 1.41-9.12; p = 0.007).

CONCLUSION

Despite previous studies showing that protease inhibitors decreased Candida adhesion to epithelial cells in vitro, the current study found protease inhibitor-containing antiretroviral therapy predisposed to oropharyngeal yeast colonization in HIV-infected patients.

Research on Candida dubliniensis in a Brazilian yeast collection obtained from cardiac transplant, tuberculosis, and HIV-positive patients, and evaluation of phenotypic tests using agar screening methods

The aim of this study was to research Candida dubliniensis among isolates present in a Brazilian yeast collection and to evaluate the main phenotypic methods for discrimination between C. albicans and C. dubliniensis from oral cavity. A total of 200 isolates, presumptively identified as C. albicans or C. dubliniensis obtained from heart transplant patients under immunosuppressive therapy, tuberculosis patients under antibiotic therapy, HIV-positive patients under antiretroviral therapy, and healthy subjects, were analyzed using the following phenotypic tests: formation and structural arrangement of chlamydospores on corn meal agar, casein agar, tobacco agar, and sunflower seed agar; growth at 45 °C; and germ tube formation. All strains were analyzed by polymerase chain reaction (PCR). In a preliminary screen for C. dubliniensis, 48 of the 200 isolates on corn meal agar, 30 of the 200 on casein agar, 16 of the 200 on tobacco agar, and 15 of the 200 on sunflower seed agar produced chlamydoconidia; 27 of the 200 isolates showed no or poor growth at 45 °C. All isolates were positive for germ tube formation. These isolates were considered suggestive of C. dubliniensis. All of them were subjected to PCR analysis using C. dubliniensis-specific primers. C. dubliniensis isolates were not found. C. dubliniensis isolates were not recovered in this study done with immunocompromised patients. Sunflower seed agar was the medium with the smallest number of isolates of C. albicans suggestive of C. dubliniensis. None of the phenotypic methods was 100% effective for discrimination between C. albicans and C. dubliniensis.

Candida species isolated from urban bats of Londrina-Paraná, Brazil and their potential virulence

The aim of this study was to isolate yeasts from the faeces of urban bats inhabiting the city of Londrina, Paraná, Brazil and to determine their potential virulence attributes. Seven (12.3%) of 57 bats screened in this study showed yeasts in their faeces. Five species of the genus Candida were isolated: C. guilliermondii, C. krusei, C. lusitaniae, C. parapsilosis, and C. pelliculosa. No phospholipase activity was detected in the egg yolk plate assay; however, all isolates demonstrated protease secretion in skim milk agar. Yeasts isolated from bats produced biofilm on the surface of polystyrene plates and all were classified as intermediate biofilm producers. Minimal inhibitory concentration (MIC) values for fluconazole in the yeasts varied according to the species. Only one isolate (M34 - C. lusitaniae) was considered susceptible dose-dependent to fluconazole. The yeasts were injected intravenously into Swiss mice, and at 15 days post-infection, the animals were killed and portions of their kidneys cultured on Sabouraud dextrose agar medium. All tissues analysed showed positive cultures of Candida spp. This is the first study evaluating the presence of fungi in the faeces of bats in an urban region, where the yeast species found were shown to be potentially pathogenic. As bats are commonly found in cities, these findings indicate the need for continuous surveillance concerning environmental contamination by their excreta.

Oral Candida isolates among HIV-infected subjects in Nigeria

BACKGROUND

Nigeria is a West African country of more than 150 million persons with the second highest case of HIV/AIDS infected patients in the world. The species spectrum of oral yeast colonization and the susceptibility to a wide range of antifungal agents is poorly understood in Nigeria especially in the south east, south south, and the northern axis. This study evaluates the species spectrum of oral colonization by Candida species in HIV-infected patients in Nigeria and the in vitro susceptibility pattern of the Candida isolates to a broad range of antifungal agents.

METHODS

Two hundred oropharyngeal swabs from HIV-infected patients and 100 age-matched healthy controls were screened for yeast isolates using standard procedures and confirmed by the analytical profile index 20C along with other biochemical tests. In vitro susceptibility testing of the yeast isolates to antifungals were performed using the broth microdilution method protocol recommended by the Clinical Laboratory Scientific Institute.

RESULTS

Of 200 patients screened, 120 (60%) were colonized by yeasts. C albicans was the dominating species in both groups with 54 (45%) isolated from HIV subjects. The non-albicans Candida species accounted for 55% with C tropicalis 22 (18.3%) showing the highest frequency. We observed that 11.7% of all yeasts isolates were resistant to fluconazole, 8.3% to flucytosine, 7.5% to itraconazole, and 1.7% to voriconazole. All isolates were susceptible to amphotericin B and most of them demonstrated very low voriconazole minimal inhibitory concentrations. Apart from C albicans, C tropicalis and C parapsilosis isolates were also recovered from apparently healthy control subjects.

CONCLUSION

Although C albicans continues to be the dominant Candida species in oral Candida carriage of HIV-infected patients in Nigeria, the nonalbicans Candida species are increasing. Furthermore, the finding of resistant isolates in our study emphasizes the need for antifungal susceptibility testing whenever antifungal treatment is desired especially in HIV-infected subjects.

Candida tropicalis in human disease

Candida tropicalis is one of the more common Candida causing human disease in tropical countries; the frequency of invasive disease varies by geography causing 3--66% of candidaemia. C. tropicalis is taxonomically close to C. albicans and shares many pathogenic traits. C. tropicalis is particularly virulent in neutropenic hosts commonly with hematogenous seeding to peripheral organs. For candidaemia and invasive candidiasis amphotericin B or an echinocandin are recommended as first-line treatment, with extended-spectrum triazoles acceptable alternatives. Primary fluconazole resistance is uncommon but may be induced on exposure. Physicians in regions where C. tropicalis is common need to be mindful of this lesser-described pathogen.

Conventional and alternative antifungal therapies to oral candidiasis

Candida-associated denture stomatitis is the most common form of oral candidal infection, with Candida albicans being the principal etiological agent. Candida adheres directly or via an intermediary layer of plaque-forming bacteria to denture acrylic. Despite antifungal therapy to treat denture stomatitis, infection is reestablished soon after the treatment ceases. In addition, many predisposing factors have been identified as important in the development of oral candidiasis, including malnourishment, common endocrine disorders, such as diabetis mellitus, antibacterial drug therapy, corticosteroids, radiotherapy and other immunocompromised conditions, such as acquired immunodeficiency syndrome (AIDS). These often results in increased tolerance to the most commonly used antifungals. So this review suggests new therapies to oral candidiasis.

A new topical treatment protocol for oral hairy leukoplakia

OBJECTIVE

The aim of this study was to present a new topical treatment protocol for oral hairy leukoplakia (OHL), consisting of a 25% podophyllin resin with a 1% penciclovir cream (PP), and to compare this topical treatment protocol's efficacy with that of 2 other topical treatment protocols: a 25% podophyllin resin (P) and a 25% podophyllin resin with a 5% acyclovir cream (PA).

STUDY DESIGN

Forty-two human immunodeficiency virus-positive patients with 69 OHL lesions were randomly treated using P, PA, or PP (14 patients in each topical treatment protocol). Clinical healing was determined when the white plaque could no longer be seen in the primary location of the lesion. Topical treatment performance was evaluated by clinical healing within each week of topical treatment protocol as well as by the recurrence of the lesion. Statistical survival analysis was performed using a Cox proportional hazards model.

RESULTS

Approximately 55% of the patients presented with clinical healing of OHL within 7-8 weeks of each topical treatment protocol. After the sixth week, the PA treatment protocol presented a faster clinical healing rate of OHL. Recurrence was observed in 3 and 7 OHL lesions treated with P and PP treatment protocols, respectively.

CONCLUSIONS

The PP treatment protocol proved to be effective; however, the PA treatment protocol was more effective in the clinical healing rate for OHL than P and PP after the sixth week of treatment, and no recurrent OHL was observed in the PA treatment group.

In vitro activity of voriconazole against Mexican oral yeast isolates

Oral candidiasis is the most prevalent complication in HIV-infected and AIDS patients. Topical antifungal treatment is useful for the initial episodes of oral candidiasis, but most patients suffer more than one episode and fluconazole or itraconazole can help in the management, and voriconazole may represent a useful alternative agent for the treatment of recalcitrant oral and oesophageal candidiasis. The aim of this research was to study the in vitro activity of voriconazole and fluconazole against Mexican oral isolates of clinically relevant yeast. The in vitro susceptibility of 187 oral yeast isolates from HIV-infected and healthy Mexicans was determined for fluconazole and voriconazole by the M44-A disc diffusion method. At 24 h, fluconazole was active against 179 of 187 isolates (95.7 %). Moreover, a 100% susceptibility to voriconazole was observed. Voriconazole and fluconazole are highly active in vitro against oral yeast isolates. This study provides baseline data on susceptibilities to both antifungal agents in Mexico.

Levels of salivary IgA antibodies to Candida spp. in HIV-infected adult patients: a systematic review

OBJECTIVE

To perform a systematic review of published data with the aim of evaluating the levels of IgA antibodies to Candida albicans in HIV-infected adult patients.

METHODS

The search strategy was based on PubMed, Web of Science, Google Scholar, Cochrane and EMBASE databases. Also, the reference lists of included studies were searched. All abstracts found by electronic searches were independently scrutinized by two reviewers. To be eligible for review, the controlled studies had to present the following characteristics: samples of both HIV-infected adults and noninfected adults; appropriate HIV-diagnostic tests for both patient groups (case and control); IgA-diagnostic test applied to a similar population sample.

RESULTS

Of 144 studies found, only six met the initial eligibility criteria, but three were excluded after a thorough analysis. To assess the methodological quality of the three remaining studies, they were categorized according the risk of bias. The three selected studies revealed that the levels of C. albicans-specific IgA antibody were higher in HIV-infected individuals compared with the control group.

CONCLUSION

Adequate IgA antibody responses to C. albicans appear to be maintained, since the levels of these antibodies were higher in all studies selected. Although the findings of this systematic review are encouraging, the scientific evidence should be interpreted carefully because there are only a few reports in the literature, mostly because of the lack of important methodological details or the varying methodologies employed.

Phenotypical characterization of Candida spp. isolated from crop of parrots (Amazona spp.)

The purpose of this study was to characterize Candida isolates from crop of parrots. Forty baby parrots of genus Amazona, species aestiva and amazonica that were apprehended from wild animal traffic were used: 18 presented ingluvitis and 22 other alterations, but showing general debilitation. Samples were seeded on Sabouraud dextrose agar with chloramphenicol after be obtained by the introduction of urethral probe through the esophagus. Based on morphology and biochemical reactions (API 20C) Candida was confirmed; it was still searched the production of proteinase and phospholipase, virulence factors for Candida species. Candida spp. were isolated from 57.5% parrots, being 72.2% from birds with ingluvitis and 45.5% from without ones. Twenty-five strains of Candida were isolated, 60% and 40%, respectively from parrots with and without ingluvitis, and were speciated: 28% C. humicola, 24% C. parapsilosis, 20% C. guilliermondii, 20% C. famata, and 8% C. albicans. These results demonstrate that C. albicans is not the most frequent species isolated, and it is the first report that shows C. guilliermondii, C. famata, and C. humicola causing infection in parrots. Many isolates presented filamentation (76%), 100% produced proteinase and 68% phospholipase. The observation of Candida spp. producing virulence factors reinforce the pathogenic role of these yeasts in the cases studied.

Mucosal Candida infection and colonisation as well as associated risk factors in solid organ transplant recipients

More detailed information on Candida colonisation and infection of the mucous membranes in organ transplant recipients (OTR) is of particular interest. Therefore, this issue was prospectively evaluated in 400 different OTR in different posttransplantation periods as well as in 405 healthy age- and sex-matched controls. In addition, possible risk factors and the clinical condition in the OTR were evaluated. Independent of the transplanted organ there is a statistically significant decrease in the number of positive culture results, of symptomatic candidiasis and an increase of isolated non-albicans Candida species corresponding to length of the posttransplantation period. No significant differences could be observed in the OTR in association with different immunosuppressive regimen; however, higher dosages of corticosteroids and tacrolimus correlated with symptomatic candidiasis. As Candida spp. may also cause systemic infection and dissemination, additional knowledge about cofactors and associated strains may have an impact on therapeutic decisions.

Antifungal suscepitibility profile of candida spp. oral isolates obtained from denture wearers

Denture stomatitis is an inflammatory condition that occurs in denture wearers and is frequently associated with Candida yeasts. Antifungal susceptibility profiles have been extensively evaluated for candidiasis patients or immunosupressed individuals, but not for healthy Candida carriers. In the present study, fluconazole, itraconazole, voriconazole, terbinafine and 5-flucytosin were tested against 109 oral Candida spp. isolates. All antifungal agents were effective against the samples tested except for terbinafine. This work might provide epidemiological information about Candida spp. drug susceptibility in oral healthy individuals.

In vitro antifungal susceptibility of clinical isolates of Candida spp. obtained from patients with different predisposing factors to candidosis

The increase in the number of infections caused by Candida species and the consequent use of antifungal agents favours an increase of resistant isolates. The aim of this study was to evaluate the antifungal susceptibility of Candida spp. isolates from patients with different systemic predisposing factors to candidosis. Seventy-nine Candida spp. isolates were assayed for in vitro susceptibility to amphotericin B, fluconazole, 5-flucytosine and itraconazole using the technique proposed by the Clinical and Laboratory Standards Institute (CLSI). Four C. albicans, one C. guilliermondii, four C. parapsilosis and two C. tropicalis isolates were resistant to amphotericin B. Only two isolate was resistant to itraconazole. All the isolates tested were susceptible to fluconazole and flucytosine. It could be concluded that the most efficient drugs against the Candida isolates studied were fluconazole and flucytosine and that all of the antifungal agents used in this study were effective against the Candida spp. isolates tested.

Species distribution and in vitro antifungal susceptibility of oral yeast isolates from Tanzanian HIV-infected patients with primary and recurrent oropharyngeal candidiasis

Background

In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis.

Methods

A total of 296 clinical oral yeasts were isolated from 292 HIV-infected patients with oropharyngeal candidiasis at the Muhimbili National Hospital, Dar es Salaam, Tanzania. Identification of the yeasts was performed using standard phenotypic methods. Antifungal susceptibility to fluconazole, itraconazole, miconazole, clotrimazole, amphotericin B and nystatin was assessed using a broth microdilution format according to the guidelines of the Clinical and Laboratory Standard Institute (CLSI; M27-A2).

Results

Candida albicans was the most frequently isolated species from 250 (84.5%) patients followed by C. glabrata from 20 (6.8%) patients, and C. krusei from 10 (3.4%) patients. There was no observed significant difference in species distribution between patients with primary and recurrent oropharyngeal candidiasis, but isolates cultured from patients previously treated were significantly less susceptible to the azole compounds compared to those cultured from antifungal naïve patients.

Conclusion

C. albicans was the most frequently isolated species from patients with oropharyngeal candidiasis. Oral yeast isolates from Tanzania had high level susceptibility to the antifungal agents tested. Recurrent oropharyngeal candidiasis and previous antifungal therapy significantly correlated with reduced susceptibility to azoles antifungal agents.

Oral yeast carriage in HIV-infected and non-infected populations in Rosario, Argentina

The objectives of the present study were: (i) to assess the frequency of oral colonisation by Candida species in HIV-positive patients and to compare it with a population of HIV-negative individuals, (ii) to determine the prevalence of C. dubliniensis in both populations and (iii) to determine the susceptibility of C. dubliniensis and other Candida species isolated from HIV-positive patients to the most commonly used antifungal agents. Oral samples were obtained from 101 HIV-positive and 108 HIV-negative subjects. For yeast identification, we used morphology in cornmeal agar, the API 20C Aux, growth at 45 degrees C, d-xylose assimilation, morphology in sunflower seed agar and PCR. The frequency of isolation of Candida in HIV-positive patients was: C. albicans, 60.7%; C. dubliniensis, 20.2%; C. glabrata, 5.6%; C. krusei, 5.6%; C. tropicalis, 4.5%; others, <5%. The frequency of isolation of Candida in HIV-negative patients was: C. albicans, 73.9%; C. tropicalis, 15.5%; C. dubliniensis, 2.1%; C. glabrata, 2.1%; C. parapsilosis, 2.1%; others, <5%. The oral colonisation by yeast in the HIV-positive patients was higher than that in the HIV-negative subjects. The susceptibilities of 42 Candida isolates to three antifungal agents were determined. All isolates of C. dubliniensis were susceptible to fluconazole, although several individuals had been previously treated with this drug. Out of the 42 Candida isolates, 10 presented resistance to fluconazole and 10 to itraconazole. The presence of Candida species, resistant to commonly used antifungal agents, represents a potential risk in immunocompromised patients.

[In vitro antifungal activity of voriconazole: New data after the first years of clinical experience]

Voriconazole has been developed to meet the increasing need for new and useful antifungal agents for the treatment of invasive mycoses. This review describes the spectrum of voriconazole antifungal activity based on data from in vitro studies published during the last three years. This survey demonstrates that voriconazole has a broad antifungal spectrum against the most common fungal pathogens being its action fungistatic for Candida and fungicidal for Aspergillus and other filamentous fungi. Overall, more than 95% of all Candida isolates tested are susceptible to voriconazole and less than 3% are resistant. Similar or even better activity rates have been described for Aspergillus, Cryptococcus and most of yeasts and moulds of medical importance. We also discuss the limitations related to the azole cross-resistance observed in some Candida glabrata isolates, the poor activity of voriconazole against Scedosporium prolificans, its activity against fungal biofilms and the great potential usefulness of combination of voriconazole with other antifungal drugs.