API 20C Research Articles

Candida albicans identification: comparison among nine phenotypic systems and a multiplex PCR.

Candida albicans is the most common fungal pathogen isolated from clinical samples and is also the most common yeast species carried as a commensal by healthy individuals although some non-C. albicans species account for an important number of infections. To compare nine phenotypic systems for C. albicans identification [API 20C AUX; RapID Yeast Identification panel (RYIP); Vitek2 ID-YST system; chromogenic media, CHRO-Magar, Oxoid Chromogenic Candida Agar (OCCA), Candida ID2, Candida Identification Agar, CandiSelect 4, and Chromalbicans Agar] with multiplex PCR. A collection of 390 yeast strains was obtained by routine isolation from oral and vaginal swabs. All of the yeasts isolated were tested for germ tube formation, and then submitted to a multiplex PCR protocol tested in previous studies, and to nine phenotypical commercial methods, together with the reference ATCC strains. Comparison was limited to the ability of the tests to identify C. albicans. 253 isolates were provisionally identified as C. albicans by germ tube, and their identities were further confirmed with the multiplex PCR. Sensitivity of phenotypical systems ranged from 81.9% (Vitek2) to 87.7% (Candida ID2 e CHROMagar). For specificity, the highest value was 96.8% for Candida ID2, and the lowest value (75.1%) was for Chromalbicans Agar. Although with differences in discriminatory power, the methods tested showed overall acceptable levels of sensitivity and specificity respect to the multiplex PCR; therefore, all could be useful for C. albicans identification where molecular differentiation is not available.

Cutaneous infection caused by Trichosporon dermatis: first case report in China.

Objective To report a case of cutaneous infection due to Trichosporon dermatis. Methods Lesional discharge and tissue were obtained and subjected to microscopic examination, fungal culture and histopathology, respectively. The fungal isolate was then identified with DNA sequence analysis, API 20C AUX system, gelatin liquefaction test, thermal tolerance test. Antifungal susceptibility test was also performed for the fungus. Results A 70-year-old male presented with a 9-month history of ulcerated swelling of the right medial malleolus after plant puncture. Direct microscopic examination of lesional discharge showed no fungal elements, but histopathological biopsy revealed hyphae and spores in the dermis. Yellowish white yeast-like colony grew on Sabouraud dextrose agar (SDA). Slide culture showed pseudohyphae, true hyphae, arthroconidia and blastoconidia. The isolate was identified as Candida humicola by API 20C AUX system, but as T. dermatis by DNA sequence analysis. The strain was unable to liquefy gelatin, could grow at 25 ℃ to 40 ℃, and was sensitive to amphotericin B, itraconazole, voriconazole and nystatin. The skin lesion completely subsided after 4-month treatment with oral itraconazole. Conclusions The isolate is identified as T. dermatis according to morphological features and DNA sequence, which is sensitive to itraconazole. Key words: Piedra; Trichosporon; Itraconazole

Evaluation of risk factors in patients with vulvovaginal candidiasis and the value of chromID Candida agar versus CHROMagar Candida for recovery and presumptive identification of vaginal yeast species

Vulvovaginal candidiasis (VVC), particularly the recurrent form, remains an intractable problem for clinicians, microbiologists, and patients. It is essential to confirm the clinical diagnosis by mycological methods and avoid empirical therapy. The recovery of yeast in fungal culture, such as on Sabouraud dextrose agar, remains the gold standard for diagnosis. In this investigation, we examined 474 participants, including 122 (25.7%) with acute VVC cases, 249 (52.5%) who had recurrent VVC (RVVC) cases, and 103 (21.7%) healthy controls. We also administered a questionnaire to obtain information on patient lifestyle and medical, gynecological, and sexual history. In addition, we compared the performance of chromID Candida agar (CAN2) to CHROMagar Candida (CAC) and Sabouraud dextrose agar with gentamicin and chloramphenicol (SGC2). The yeasts were identified by conventional methods including the germ tube test, microscopic morphology on cornmeal-Tween 80 agar, and the commercial API 20C AUX system. We detected yeasts in 60 of 122 (49.2%) patients with acute VVC cases, 110 of 249 (44.2%) with RVVC cases, and in 35 of 103 (34%) healthy controls (P = 0.07). A total of 205 samples were found to be positive for fungi (43.2%), of which 176 (85.9%) were monofungal, and 29 (14.1%) were polyfungal. In addition, 198 of these samples (96.6%) were positive on CAN2, 195 (95.1%) on CAC, 189 (92.2%) on SGC2, and 183 (89.3%) samples on all three (P = 0.17). The 234 yeast isolates recovered were C. albicans (n = 118), C. glabrata (n = 82), C. kefyr (n = 11), C. krusei (n = 9), C. lipolytica (n = 3), C. colliculosa (n = 2), C. parapsilosis (n = 2), C. pelliculosa (n = 2), C. tropicalis (n = 2), and other species of Candida (n = 3). Of the 29 polyfungal populations, 28 (96.6%) were detected in CAN2, 25 in (86.2%) CAC, and 25 (86.2%) on both (P = 0.35). Notably, we detected the high predominance of C. albicans+C. glabrata (86.2%) in polyfungal populations. Briefly, the detection of C. albicans after 24 h of incubation was easier on CAN2 (64.4%) than on CAC (25.4%). This study showed that CAN2 is a rapid and reliable medium for immediate identification of C. albicans and for detecting polyfungal populations in vaginal specimens. We observed that the use of antibiotics, intrauterine devices, as well as, perineal laceration, short anovaginal distance (< 3 cm), and genital epilation in common areas are predisposing factors for RVVC (P < 0.001). In addition, we detected that the use of menstrual pad, using an (IUD), and having a history of childbirth increased the risk of both acute and recurrent VVC (P < 0.01), whereas the use of a daily pad and walking daily significantly decreased the risk of both acute and recurrent VVC (P < 0.01).

Biosynthesis of polyhydroxyalkanotes in wildtype yeasts

Biosynthesis of the biodegradable polymers polyhydroxyalkanotes (PHAs) are studied extensively in wild type and genetically modified prokaryotic cells, however the content and structure of PHA in wild type yeasts are not well documented. The purpose of this study was to screen forty yeast isolates collected from different Egyptian ecosystems for their ability to accumulate PHAs. Identification of the isolates and characterization of PHAs produced by the positive strains in the Nile-red staining assay was envisaged. One positive isolates which was identified using the API 20C yeast identification system as Rhodotorula minuta strain RY4 produced 2% of PHA in biomass, in glucose, oleic acid and tween 60 containing medium, over a growth period of 96 h. The nature of the PHA thus produced was analyzed by infrared spectroscopy and nuclear magnetic resonance (1H and 13C NMR) and found to contain polyhydroxybutyrate and polyhydroxyvalerate. This study shows for the first time monomerdetection by 1H and/or 13C NMR of PHA polymers synthesized in wild type yeasts.

Prevalence of pulmonary cryptococcosis in hiv/aids patients

Cryptococcus neoformans causes both pulmonary and meninges infection in healthy and immunocompromised hosts. The objective of this study was to determine the prevalence of pulmonary cryptococcosis in HIV/AIDS patients and assess the clinical presentations due to the infection. The subjects recruited for this study were confirmed HIV/AIDS patients, presenting with pneumonia complications. The demographic and clinical features were abstracted from the medical records and administered questionnaire. Early morning sputum samples were collected from the patients and examined by bacteriological methods. The isolated Cryptococcus neoformans were sub-cultured onto thistle bird seed agar and the identity was confirmed with API 20C Kit. Out of 250 patients investigated, 47 (18.8%) had pulmonary cryptococcosis. The C.neoformans isolates were more in females, 26 (10.4%) than the males, 21 (8.4%), while the age group of 20-40 years old had 39 (15.6%) isolates. The clinical features that were associated with the pulmonary cryptococcosis were the production of purulent and bloody sputum, and fever. The patients with prolonged duration of HIV/AIDS and are not on HAART regimens had higher C.neoformans isolates. The isolation of C.neoformans from HIV/AIDS patients is a major public health concern, since it complicates the severity of the disease. There is a need for routine check of pulmonary cryptococcosis, especially, in those who do not avail themselves for antiretroviral therapy.

Peri‐implant parameters in head and neck reconstruction: influence of extraoral skin or intraoral mucosa

This study is designed to assess dental implants supporting overdentures in edentulous patients with operated head and neck malignancies using parameters to detect peri-implant disease. Thirty-four implants supporting overdentures in 34 oral cancer patients were examined. Clinical parameters [plaque index, probing depth, bleeding on probing (BOP), origin of peri-implant soft tissue, and amount of irradiation] were recorded, and microbiological identification of periodontal pathogens was carried out by DNA-DNA hybridization. To identify yeast species, the samples were cultivated on Sabouraud agar plates and subsequently identified by API 20C AUX plates. An implant site showing BOP, probing pocket depth (PPD)>or=5 mm and radiographic vertical bone loss was considered to have peri-implant disease. Colonization by periodontal pathogens was found on 15 implants, while yeast species were found in 14 cases. Using a univariate analysis, none of the investigated parameters (microbiologic sign, detection of yeast, origin of peri-implant soft tissue and irradiation) were significantly correlated to signs of peri-implant disease. In the multivariate analysis, yeast [odds ratio (OR) 12.32, P=0.033] and periodontal pathogen (OR 9.88, P=0.046) were significant predictor variables for peri-implant disease. Yeasts were less frequently detected around implants placed in re-vascularized skin flaps if irradiation was set as a confounder (P=0.019). With respect to the pilot study nature of the study peri-implant soft tissue origin and irradiation had little influence on the development of peri-implant disease. Yeast and periodontal pathogen were explanatory variables for the development of peri-implant disease. Considering the effect of irradiation on the prevalence of yeast, yeast was less frequently observed in peri-implant soft tissue of the skin. Based on these data, future studies on the role of yeast and soft tissue in peri-implant disease should be encouraged.

Performance of Chromogenic Candida Agar and CHROMagar Candida in recovery and presumptive identification of monofungal and polyfungal vaginal isolates

Chromogenic Candida agar (OCCA) is a novel medium facilitating isolation and identification of Candida albicans, C. tropicalis, and C. krusei, as well as indicating polyfungal population in clinical samples. We compare the performance of OCCA, to CHROMagar Candida (CAC) and Sabouraud chloramphenicol agar (SCA). Vaginal swab samples from 392 women were simultaneously inoculated onto three study media. A total of 161 (41.1%) were found to be positive for fungi of which 140 (87%) were monofungal, and 21 (13%) polyfungal. One-hundred and fifty-seven samples (97.5%) were positive on CAC, 156 (96.9%) on OCCA, 148 (91.9%) on SCA and 144 (89.4%) samples were positive on all three media. The yeasts were identified by conventional methods including germ tube test, microscopic morphology on cornmeal-Tween 80 agar, and the commercial API 20C AUX. The 182 isolates were C. albicans (n = 104), C. glabrata (n = 51), C. krusei (n = 7), C. tropicalis (n = 5), C. famata (n = 3), C. kefyr (n = 3), C. zeylanoides (n = 3), C. colliculosa (n = 2), and other species of Candida (n = 4). Among the 21 polyfungal populations, 20 (95.2%) were detected in OCCA, 14 (66.7%) in CAC, and 13 (61.9%) in CAC and OCCA (P <0.05). Most polyfungal populations (47.6%) yielded C. albicans + C. glabrata. The efficiency of both chromogenic media for C. albicans was >or=92.9% at 72 h. OCCA is more efficient and reliable for rapidly identifying C. albicans and polyfungal populations than CAC. However, CAC is more efficient for identifying C. krusei and C. tropicalis. A chromogenic agar with a higher isolation rate of yeasts and better detection of polyfungal populations than SCA, is suggested as a medium of first choice when available.

Phenotypic characterization of mastitic Prototheca spp. isolates

Bovine mastitis associated with Prototheca is considered a rare pathology, but is increasing in prevalence all over the world and therefore becoming more relevant to the dairy industry. The biochemical characterization of 47 Prototheca isolates retrieved from mastitic milk was performed in this study using API 20C Aux and two BBL Crystal Kits, followed by an analysis with InforBio software. The usage of this methodology, allowed the identification of discriminative phenotypic characteristics for the strains tested. The differential-character-finding algorithm used by this software permitted the identification of new phenotypic characteristics to discriminate between Prototheca zopfii, P. blaschkeae and P. wickerhamii, such as, citrate, phosphorycholine and arabinoside. The main objective of this study was to determine new phenotypic characteristics that allowed a better characterization of Prototheca spp. Usage of recent bioinformatic tools improved the analyses of several features that are important for a better characterization of Prototheca spp.

Identifcation of yeasts from raw milk and selection for some specific antioxidant properties

Eleven different species of yeasts isolated from raw milk, such as Issatchenkia orientalis, Pichia fermentans, Rhodotorula mucilaginosa and Yarrowia lipolytica were identified using an integrated approach, including phenotypic and genotypic methods and the API 20C AUX system. Eleven selected strains which tolerated low pH levels, gastric juice and bile salt were further analysed for the presence of functional traits useful for probiotic application as antioxidants. The ability to scavenge DPPH (2, 2‐diphenyl‐1‐picrylhydrazyl) and inhibit linoleic acid peroxidation indicated that P. fermentans BY5 and HJ15 may be promising candidate strains for use as probiotics with antioxidant activity.

A Fatal Case ofCandida orthopsilosisFungemia

Candida orthopsilosis is a recently described Candida species phenotypically indistinguishable from Candida parapsilosis. This new species can be identified only by using molecular methods. We describe here a fatal case of fungemia caused by C. orthopsilosis in a 75-year-old male patient who had panperitonitis after total gastrectomy with Roux-en-Y esophagojejunostomy. All 18 blood cultures obtained from admission day 16 to day 68 yielded the same Candida species. Both Vitek 2 (bioMerieux, Inc., Hazelwood, MO, USA) and API 20C (bioMerieux, Marcy-l'Etoile, France) failed to identify these isolates. However, DNA sequencing analysis of both D1/D2 domain and internal transcribed spacer region of rDNA showed 100% identity with C. orthopsilosis. The fungemia was persistent over 50 days despite of systemic antifungal therapy including fluconazole and caspofungin, and the patient expired on day 73 of his hospital stay. This represents the first reported case of fatal fungemia by C. orthopsilosis in Korea.

Genotyping of Trichosporon asahii strains isolated from urinary tract infections in a Turkish university hospital

Trichosporon infections are associated with a wide spectrum of clinical manifestations. Trichosporon asahii is the most important species in the genus. Our aim was to evaluate the genotypic relatedness of urinary T. asahii strains isolated from immunocompetent patients during a hospital outbreak. Materials and methods: Twenty-three T. asahii isolates obtained from 15 patients hospitalized in different wards of Ankara University Ibn-i Sina Hospital between July 2004 and April 2005 were studied. T. asahii was identified by API 20C AUX (BioMérieux Vitek, Hazelwood, USA) system and confirmed by genus and species specific polymerase chain reactions. Genetic relatedness of the isolates was evaluated by randomly amplified polymorphic DNA (RAPD) and repetitive element PCR (REP-PCR) analyses. Results: RAPD analysis divided the isolates into 5 groups. The results of REP-PCR correlated well with the data obtained by RAPD analysis, although this method produced 3 different groups. Conclusion: In this study of urinary trichosporonosis, 19 of the 23 isolates were found to be genotypically related, suggesting that a single genotype was prevalent in our hospital environment. The genotypically unrelated 4 isolates were probably of endogenous origin. RAPD and REP-PCR analyses can be used for genotyping T. asahii strains.

Comparison of Whole Blood, Serum, and Plasma for Early Detection of Candidemia by Multiplex-Tandem PCR

We applied multiplex-tandem PCR (MT-PCR) to 255 EDTA whole-blood specimens, 29 serum specimens, and 24 plasma specimens from 109 patients with Candida bloodstream infection (candidemia) to determine whether a diagnosis could be expedited in comparison with the time to diagnosis by the use of standard blood culture. Overall, the MT-PCR performed better than blood culture with DNA extracted from whole blood from 52/74 (70%) patients, accelerating the time to detection (blood culture flagging) and determination of the pathogenic species (by use of the API 32C system [bioMérieux, Marcy l'Etoile, France]) by up to 4 days (mean, 2.2 days; range, 0.5 to 8 days). Candida DNA was detected more often in serum (71%) and plasma (75%) than in whole blood (54%), although relatively small numbers of serum and plasma specimens were tested. The sensitivity, specificity, positive predictive value, and negative predictive value of the assay with whole blood were 75%, 97%, 95%, and 85%, respectively. Fungal DNA was not detected by MT-PCR in 6/24 (25%) whole-blood samples drawn simultaneously with the positive blood culture sample. MT-PCR performed better with whole-blood specimens stored at -20 degrees C (75%) and when DNA was extracted within 1 week of sampling (66%). The molecular and culture identification results correlated for 61 of 66 patients (92%); one discrepant result was due to misidentification by culture. All but one sample from 53 patients who were at high risk of candidemia but did not have proven disease were negative by MT-PCR. The results demonstrate the good potential of MT-PCR to detect candidemia, to provide Candida species identification prior to blood culture positivity, and to provide improved sensitivity when applied to with serum and plasma specimens.

OralCandidacolonization and its relation with predisposing factors in HIV-infected children and their uninfected siblings in Brazil: the era of highly active antiretroviral therapy

To evaluate predisposing factors such as orofacial manifestations, immunosuppression status and antiretroviral therapy in relation to oral colonization by Candida spp. in Brazilian HIV-infected children and their uninfected siblings in the era of highly active antiretroviral therapy (HAART). Whole stimulated saliva was collected from 65 HIV-infected children (HIV+) and 40 uninfected siblings (HIV-), followed by assessment of orofacial manifestation, caries indexes and the number of cavitated dentinal carious teeth (CDT). The salivary samples were cultured and the colonies were counted. After which they were identified by sugar assimilation and fermentation (API 20C). Data was analyzed using chi-square, Mann-Whitney, Spearman tests and logistic regression. Regarding positive growth, HIV+ presented 80% (52/65) and HIV- 57.5% (23/40) (P = 0.013). Absence of antiretroviral therapy and HAART increased the probability of Candida isolation (P < 0.05). Mean CD4%, immune-status and history of recurrent oral candidiasis (OC) had no influence on Candida isolation. Mixed Candida spp. cultures were observed in HIV+ (40%) and HIV- (52%): C. albicans was more frequently found in both groups, with a higher prevalence in HIV+ (P = 0.05); other non-albicans species were isolated in HIV+ and HIV-. Low prevalence of orofacial manifestations was observed in HIV+ (10.7% of OC). There was an association between means of CDT and Candida growth (P < 0.05) and a positive correlation between number of CDT and Candida cfu-counts in HIV+ and HIV-. Mean CD4% and immune-status had no influence on Candida isolation. Absence of antiretroviral therapy and HAART increased the probability of Candida isolation (P < 0.05). The HIV infected children had a significantly higher prevalence of oral Candida spp. compared to their uninfected siblings. Absence of HAART and presence of dentinal carious teeth increased significantly Candida spp. colonization in these children.

Prevalence of Candida Species in Fresh Fruit Juices

Fruit juices are popular soft drinks with an important role in human nutrition. Fruit juices are often infested by yeast species that can survive different storage conditions. The aim of this study was to determine the degree of yeast contamination of freshly squeezed juices in three large supermarkets in Zagreb, Croatia. The analysis included 84 juice samples obtained from freshly squeezed orange, lemon, grapefruit, and apples. Their acidity varied between pH 2.1 and pH 4.9. Juice samples were plated directly on Sabouraud 4 % glucose Agar (Merck, 1.05438) and processed according to standardised methods (HRN ISO 7954:2002). Yeasts were isolated in all 84 samples and ranged between 0.005 x 103 and 23 x 103 colony forming units per mL (CFU mL-1). The most common yeasts identified using the API 20C AUX yeast kit included Candida guillermondii, C. krusei, C. famata, C. spherica, C. colliculosa, C. albicans, Trichosporon mucoides, Kloeckera spp. and yeast-like fungus Cryptococcus neoformans. C. guillermondii prevailed in 55.95 % of all samples.

Fatal Algaemia in Patient with Chronic Lymphocytic Leukemia

Fatal Algaemia in Patient with Chronic Lymphocytic Leukemia

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.

Fluconazole-resistant Kodamaea ohmeri fungemia associated with cellulitis: Case report and review of the literature

Kodamaea (Pichia) ohmeri was formerly considered a contaminant, but is now known to be a significant human pathogen that has been shown to cause fungemia, endocarditis, funguria, and peritonitis in immunocompromised patients. We report a case of fungemia caused by K. ohmeri in a 71-year-old man with cellulitis. The patient was sent to the emergency room due to leg edema, fever, and change of consciousness. During hospitalization, a series of examinations including blood cultures were performed. On hospital day 8, blood culture yielded a yeast colony. Fluconazole was given empirically, but had no effect. The pathogen was identified as K. ohmeri by Vitek YBC card, API 20C, sequencing of the 18S rRNA gene, and the D1/D2 domains of the 26S rRNA gene and the internally transcribed spacer (ITS) regions. Antifungal susceptibility testing was performed with the ATB-Fungus system, and a high minimum inhibitory concentration (level up to 64 mg/l) for fluconazole was found. Fluconazole was replaced with amphotericin B deoxylate, and the fever and cellulitis inflammation gradually subsided. The patient was discharged in a stable condition. This is the first case of K. ohmeri fungemia in Taiwan.

Differential diagnosis of denture‐induced stomatitis, Candida, and their variations in patients using complete denture: a clinical and mycological study

Denture-induced stomatitis usually occurs in persons who wear a complete or a partial denture. Among the many aetiological and predisposing factors, Candida spp. are believed to play an important role in the initiation and progression of the infection. Seventy cases who attended the clinics of the Dental Faculty, University of Atatürk, Turkey were investigated from the viewpoint of denture-induced stomatitis. After questioning the patients for their personal information, they were examined clinically and smears were obtained from lesions of the palatal mucosa and the contiguous denture surface by calcium aliginate swabs, and inoculated onto Sabouraud dextrose agar supplemented with 1% chloramphenicol, and CHROMagar Candida. Individual yeast species were identified by a germ tube test, development of blastospores, chlamydospores and pseudohyphae and assimilation tests employing the commercial kit API 20C AUX system. According to the results obtained, 70% of the cases had denture-induced stomatitis, and in 68% of them mycological culture results were positive. Candida albicans was the most frequently isolated fungus (68.75%). On the other hand, fungal growth was much more pronounced in the cultures made from the inner surface of the dentures. In conclusion, this study showed that candidal infections are not the predisposing factor in the occurrence of denture-induced stomatitis, but they play a major role, as also some other factors, especially those related with dentures.

Oral candidiasis: a comparison between conventional methods and multiplex polymerase chain reaction for species identification

Oral candidiasis is the most common fungal infection in dental practice, and is caused by yeasts that are normally present in the endogenous flora. To evaluate a rapid diagnostic method for identification of Candida oral isolates, a multiplex polymerase chain reaction (PCR) was carried out on colonies and on oral rinse solutions from 95 subjects with suspected oral candidiasis and results were compared with those from seven commonly used phenotypic identification systems. Between four and nine species were characterized in the samples by the phenotypic methods. PCR identified the same species in 60 (74%) samples from both colony and oral rinse solutions. Statistical analysis, carried out only for the three most frequently isolated species (Candida albicans, Candida glabrata, and Candida tropicalis), showed good concordance in the comparison of multiplex PCR with API 20C AUX and with the Rapid Yeast Identification Panel; conversely, significant differences were registered in the comparison between the molecular method and other phenotypic systems, including four chromogenic media and the automated system Vitek2. Multiplex PCR was rapid and effective in the identification of Candida species and allowed the detection of more than one species in the same sample.

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.