Carbohydrate Assimilation Profiles Research Articles

Inspecting Candida Oral Infections among Diabetics

Objective: Oral candidiasis infection is more prevalent in diabetic patients. There are numerous factors that can exacerbate the colonization of Candida species in the oral cavity, including salivary pH disorders and xerostomia. The study aimed to evaluate Candida spp. resistance to antifungal agents and compare their colonization levels in diabetics and nondiabetics oral cavities. Methods: We conducted the investigation from February 2023 to April 2023. We conducted the following analyses after collecting 100 oral samples: gram stain, culture on Sabaroud dextrose agar, and direct microscopic inspection. The Vitek 2 System confirmed the yeasts through carbohydrate assimilation profiles. Results: Out of 100 oral samples cultured, 69 yielded Candida species. Fifty-two samples were from diabetics and 17 were from nondiabetic patients. The frequencies of isolated Candida species, including C. albicans, were 28, C. tropicalis 17, C. krusei 16, C. glabrata 6, and C. dubliniensis 2. The results indicated that C. albicans exhibited higher resistance rates against clotrimazole, itraconazole, and voriconazole than the no albicans Candida species. Clotrimazole, itraconazole, and voriconazole, on the other hand, showed no effect on 11, 29, and 18 samples for all Candida species, respectively. Conclusion: C. albicans was the most prevalent Candida species in people with diabetes; however, other Candida species were common. Fluconazole and nystatin often treat oral Candida infections.

Dual Role of Probiotic Lactic Acid Bacteria Cultures for Fermentation and Control Pathogenic Bacteria in Fruit-Enriched Fermented Milk.

The food industry has been developing new products with health benefits, extended shelf life, and without chemical preservation. Bacteriocin-producing lactic acid bacteria (LAB) strains have been evaluated for food fermentation to prevent contamination and increase shelf life. In this study, potentially probiotic LAB strains, Lactiplantibacillus (Lb.) plantarum ST8Sh, Lacticaseibacillus (Lb.) casei SJRP38, and commercial starter Streptococcus (St.) thermophilus ST080, were evaluated for their production of antimicrobial compounds, lactic acid and enzyme production, carbohydrate assimilation, and susceptibility to antibiotics. The characterization of antimicrobial compounds, the proteolytic activity, and its inhibitory property against Listeria (List.) monocytogenes and Staphylococcus (Staph.) spp. was evaluated in buriti and passion fruit-supplemented fermented milk formulations (FMF) produced with LAB strains. Lb. plantarum ST8Sh was found to inhibit List. monocytogenes through bacteriocin production and produced both L(+) and D(-) lactic acid isomers, while Lb. casei SJRP38 mainly produced L(+) lactic acid. The carbohydrate assimilation profiles were compatible with those usually found in LAB. The potentially probiotic strains were susceptible to streptomycin and tobramycin, while Lb. plantarum ST8Sh was also susceptible to ciprofloxacin. All FMF produced high amounts of L(+) lactic acid and the viability of total lactobacilli remained higher than 8.5 log CFU/mL during monitored storage period. Staph. aureus ATCC 43300 in fermented milk with passion fruit pulp (FMFP) and fermented milk with buritipulp (FMB), and Staph. epidermidis KACC 13234 in all formulations were completely inhibited after 14days of storage. The combination of Lb. plantarum ST8Sh and Lb. casei SJRP38 and fruit pulps can provide increased safety and shelf-life for fermented products, and natural food preservation meets the trends of the food market.

Marinobacter maroccanus sp. nov., a moderately halophilic bacterium isolated from a saline soil.

During the taxonomic investigation of exopolymer-producing halophilic bacteria, a rod-shaped, motile, Gram-stain-negative, halophilic bacterium, designated strain N4T, was isolated from a saline soil located in northern Morocco. Optimal growth of the isolate was at 30-37 ºC and at pH 7.0-8.0, in the presence of 5-7 % (w/v) NaCl. Useful characteristics for the phenotypic differentiation of strain N4T from other Marinobacter species included α-chymotrypsin and α-glucosidase activities and the carbohydrate assimilation profile. The major fatty acids detected in strain N4T were C16:0 and C18:1ω9c and the predominant respiratory quinone was ubiquinone-9. Sequence analysis of the 16S rRNA gene indicated that strain N4T belonged to the genus Marinobacter and was closely related to the type strains of Marinobacter adhaerens (99.04 % similarity), Marinobacter salsuginis (98.97 %) and Marinobacter flavimaris (98.36 %). Phylogenetic analysis of the rpoD gene sequence also showed that the nearest neighbours of strain N4T were M. salsuginis (91.49 % similarity), M. adhaerens and M. flavimaris (90.63 %). Strain N4T showed 87.98 % average nucleotide identity with M. flavimaris and M. salsuginis, and 87.47 % with M. adhaerens. Regarding in-silico genome-to-genome distance, strain N4T showed DNA-DNA hybridization values of 33.30 % with M. adhaerens, 34.60 % with M. flavimaris and 34.70 % with M. salsuginis. The DNA G+C content of strain N4T was 57.3 mol%. Based on the results of phenotypic characterization, phylogenetic analysis and genome comparison, strain N4T represents a novel species of the genus Marinobacter, for which the name Marinobacter maroccanus sp. nov. is proposed. The type strain is N4T (=CECT 9525T=LMG 30466T).

Emerging pathogen: Candida kefyr (Kluvyeromyces marxianus)

In the central microbiology laboratory of Gazi University Hospital Candida kefyr was isolated from different clinical samples as 5.3% in 2016 and in 2017 this rate increased to 9.3% which was nearly two-fold and this has drawn our attention. The aim of this study was to evaluate the special characteristics, antifungal susceptibility and virulence properties of C.keyfr species. Germ tube, corn meal-tween 80 agar morphology and carbohydrate assimilation profiles on ID32C yeast identification system were used for the diagnosis of Candida species. In this study, DNA sequencing was performed using ITS1 and ITS4 primers amplifying fungal gene between 5.8S and 18S regions of rRNA. Antifungal susceptibility was performed using M27A microdilution method recommended by Clinical and Laboratory Standards Institute (CLSI). Minimum inhibitory concentration (MIC) values for amphotericin B, fluconazole, voriconazole and itraconazole were determined. MIC distribution, MIC50 and MIC90 values and geometric mean (GM) were detected. The existence of virulence factors caseinase, secreted aspartyl proteinase, esterase and phospholipase were investigated in vitro. A total of 865 Candida species were isolated from different clinical samples in the central microbiology laboratory of Gazi University Hospital in 2016. Among them, 46 (5.3%) were C.kefyr. In the first four months of 2017, 30 (9.3%) C.kefyr were identified among 320 Candida isolates. Ten isolates which have shown atypical morphology on corn meal agar were selected. Among these 10 isolates, nine of them were identified as C.kefyr by using ID32C system and DNA sequencing method. Amphotericin B MIC value was 2 µg/ml for one isolate, and fluconazole MIC value was 8 µg/ml for another isolate among 46 isolates. Among the 30 isolates of the year 2017, one of them presented MIC value for fluconazole as 8 µg/ml. No marked antifungal resistance was detected in our isolate group. Caseinase was positive in one C.kefyr isolate, and phospholipase were positive in eight of nine isolates. As a result, the reason of increase in the incidence of this Candida species, which does not show significant resistance and presents mostly phospholipase activity as a virulence factor, should be investigated in more detail.

Oral mycoses in avian scavengers exposed to antibiotics from livestock farming

The exposure to antimicrobial pharmaceuticals as environmental contaminants can exert direct and indirect detrimental effects on health of wildlife. Fungal infections pose a major threat to domestic, captive-housed wild and free-ranging wild animals worldwide. However, little is known about their role in disease in birds in the wild. Here, we evaluated the incidence of thrush-like lesions in the oral cavity of wild nestling cinereous vultures (Aegypius monachus), griffon vultures (Gyps fulvus), Egyptian vultures (Neophron percnopterus) and golden eagles (Aquila chrysaetos) exposed to veterinary antibiotics via the consumption of medicated livestock carcasses. Lesions, which varied in number, size and location, were more frequent in the cinereous (77.8%, n=9) and griffon vultures (66.7%, n=48) than in the Egyptian vultures (28.6%, n=21) and golden eagles (28.6%, n=7). In all individuals (100%, n=24) of a subsample of the affected nestlings, yeast species were isolated from thrush-like oral lesions and identified using a well-established system based on their carbohydrate assimilation profiles and other complementary tests. Fourteen yeast species from seven genera (Candida, Meyerozyma, Pichia, Yarrowia, Cryptococcus, Rhodotorula and Trichosporon) were isolated from the lesions of the four host species. We found differential infections and effects depending on host age-related exposure or susceptibility to different yeast species across the development of nestling griffon vultures. This unprecedented outbreak of oral mycoses is alarming because of the delicate conservation status of several of the affected species. The role of livestock antibiotics in the transition of yeast species from commensal to opportunistic pathogens should be evaluated in an attempt to avoid the detrimental effects of contamination and disease on host health, as well as on the transmission of fungal emerging pathogens among wildlife populations and species, and their dissemination across livestock and human populations.

Otomycosis in Western Iran: Clinical and Mycological Aspects

Background: Otomycosis is a globally distributed superficial infection of the auricle and external auditory canal. Its incidence differs in various geographical regions due to the different climatic conditions. Objectives: The aim of this study was to determine the incidence of otomycosis in Khorramabad, Lorestan province, western Iran, using mycological besides clinical criteria. Methods: In this cross-sectional descriptive study, a total of 79 patients clinically suspected to otomycosis were recruited from April 2014 to April 2015. Specimens were collected using sterile swabs. All the specimens were subjected to direct examination using 10% KOH, and culture in Sabouraud dextrose agar containing chloramphenicol, malt-extract agar, and Czapek Dox agar. CHROMagar candida and carbohydrate assimilation profile in API 32 C were used for the identification of yeasts. Results: Among 79 patients, 15 (19%) were confirmed for otomycosis. The most common agent was Candida albicans (5, 33.33%), followed by Aspergillus flavus (4, 26.64%), Penicillium spp. (3, 19.98%), A. niger (2, 13.32%), and Alternaria spp. (1, 6.66%). Females were the dominant involved group (11, 73.33%) and itching was the most frequent clinical compliant in 100% of cases with otomycosis. Conclusions: Regarding the dissimilarity in fungal spectrum in our study and other investigations and unspecificity of clinical signs and symptoms for otomycosis, mycological examination could be a beneficial measure for accurate diagnosis and treatment of otomycosis.

Efficacy of Locally Isolated Lactic Acid Bacteria Against Antibiotic-Resistant Uropathogens

Background: Antibiotic resistance represents a serious global health threat to public health, so infections such as pneumonia and urinary tract infection (UTI) are becoming harder to treat. Therefore, it is necessary to develop an action plan to restrain the problem of antibiotic resistance. One approach in UTI control could be the use of lactobacilli because these indigenous inhabitants in human intestine have been found to play an important role in protecting the host from various infections. Objectives: We sought to check the efficacy of locally isolated Lactobacillus species to eradicate antibiotic-resistant pathogenic bacteria causing UTI. Materials and Methods: Lactic acid bacteria isolated from spoiled fruits and vegetables and grown in MRS medium were screened against multi-drug-resistant Candida albicans, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus fecalis. Results: Fifty-four lactic acid bacteria were isolated from spoiled fruits and vegetables, of which 11 Gram-positive and catalase-negative Lactobacillus isolates were identified by carbohydrate assimilation profiles as Lactobacillus acidophilus, L. paracasei, L. delbrueckii, L. casei, L. helveticus, L. brevis, L. salivarius, L. fermentum, L. rhamnosus, L. animalis, and L. plantarum. The latter organism had the highest abundance of all the samples, so its isolates were also verified through 16S rRNA gene sequencing. The isolated Lactobacilli were screened against multi-drug-resistant uropathogens, viz. C. albicans, P. aeruginosa, K. pneumoniae, E. fecalis, and E. coli. The growth inhibition zone (GIZ) was over 10 mm against all the uropathogenic test organisms, where L. fermentum and L. plantarum strains demonstrated remarkable inhibitory activities against E. coli and E. faecalis, with a GIZ up to 28 mm. The susceptibility test to 16 antibiotics showed multidrug resistance (3 to 5 antibiotics) among all the tested uropathogens. Conclusions: The obtained results revealed that all the Lactobacillus isolates displayed antimicrobial activity against 6 out of 7 antibiotic-resistant uropathogens, indicating that these bacteria could represent a good ecological plan for the control and prevention of UTI.

Identification and characterization of nine atypical Candida dubliniensis clinical isolates.

Candida dubliniensis is a pathogenic yeast of the genus Candida closely related to Candida albicans. The phenotypic similarity of these two species often leads to misidentification of C. dubliniensis isolates in clinical samples. DNA-based methods continue to be the most effective means of discriminating accurately between the two species. Here, we report on the identification of nine unusual Candida isolates that showed ambiguous identification patterns on the basis of their phenotypic and immunological traits. The isolates were categorized into two groups. Group I isolates were unable to produce germ tubes and chlamydospores, and to agglutinate commercial latex particles coated with a mAb highly specific for C. dubliniensis. Group II isolates grew as pink and white colonies on CHROMagar Candida and ChromID Candida, respectively. Carbohydrate assimilation profiles obtained with API/ID32C together with PCR amplification with specific primers and DNA sequencing allowed reliable identification of the nine unusual clinical isolates as C. dubliniensis.

Molecular, Physiological and Phenotypic Characterization of Paracoccus denitrificans ATCC 19367 Mutant Strain P-87 Producing Improved Coenzyme Q10.

Coenzyme Q10 (CoQ10) is a blockbuster nutraceutical molecule which is often used as an oral supplement in the supportive therapy for cardiovascular diseases, cancer and neurodegenerative diseases. It is commercially produced by fermentation process, hence constructing the high yielding CoQ10 producing strains is a pre-requisite for cost effective production. Paracoccus denitrificans ATCC 19367, a biochemically versatile organism was selected to carry out the studies on CoQ10 yield improvement. The wild type strain was subjected to iterative rounds of mutagenesis using gamma rays and NTG, followed by selection on various inhibitors like CoQ10 structural analogues and antibiotics. The screening of mutants were carried out using cane molasses based optimized medium with feeding strategies at shake flask level. In the course of study, the mutant P-87 having marked resistance to gentamicin showed 1.25-fold improvements in specific CoQ10 content which was highest among all tested mutant strains. P-87 was phenotypically differentiated from the wild type strain on the basis of carbohydrate assimilation and FAME profile. Molecular differentiation technique based on AFLP profile showed intra specific polymorphism between wild type strain and P-87. This study demonstrated the beneficial outcome of induced mutations leading to gentamicin resistance for improvement of CoQ10 production in P. denitrificans mutant strain P-87. To investigate the cause of gentamicin resistance, rpIF gene from P-87 and wild type was sequenced. No mutations were detected on the rpIF partial sequence of P-87; hence gentamicin resistance in P-87 could not be conferred with rpIF gene. However, detecting the mutations responsible for gentamicin resistance in P-87 and correlating its role in CoQ10 overproduction is essential. Although only 1.25-fold improvement in specific CoQ10 content was achieved through mutant P-87, this mutant showed very interesting characteristic, differentiating it from its wild type parent strain P. denitrificans ATCC 19367, which are presented in this paper.

Molecular and phenotypic characterization of Lactobacillus curvatus isolated from handmade Brazilian salami.

17 Lactobacillus curvatus and one Lactobacillus brevis isolate were obtained from salami. The isolates were previously selected according to the desirable characteristics regarding technological criteria. Identification was based primarily on the biochemical carbohydrate assimilation profile, and later by amplified 16S rDNA restriction analysis (ARDRA). Due to inconsistencies in the results found by the identification methods employed, the 16S rRNA gene was partially sequenced and the result confirmed identity of L. curvatus, as predicted by ARDRA, which shows that this molecular technique is efficient in identifying the species. All isolates of L. curvatus were characterized by the molecular technique of random amplified polymorphic DNA (RAPD). In order to analyze the relationships existing between the isolates, taxonomic dendrograms were obtained based on molecular profile, what was suitable for the typing. The molecular techniques are efficient in the identification of Lactobacillus sp . isolates, which can be complementary or even substitute biochemical techniques. Thus, these molecular methods offer a fast and economic way for the identification and characterization of lactic acid bacterial with a potential use as starter cultures in the elaboration of handmade fermented products. Key words: 16S amplified ribosomal DNA restriction analysis (ARDRA), random amplified polymorphic DNA (RAPD), lactobacilli, microbial genetics.

The Evaluation of the Distribution of Yeast like Fungi 'Candida Species' at a Tertiary Care Center in Western Turkey

Objective: Candida infections have increased due to transplant patients, prolonged ICU stay and invasive procedures. The most common isolated strain is C. albicans. The aim of this study was to evaluate the distribution of Candida isolates at Tepecik Education and Research Hospital.Materials and Methods: Yeast like fungi were isolated between 13.01.2010 and 19.08.2011 at Mycology Laboratory. The identification was done by conventional methods and carbohydrate assimilation profile using the ID32C identification system (Biomerieux, France).Results: Yeast like fungi were isolated from 337 clinical specimens. They consisted of urine, blood culture, respiratory specimen and wound. The most isolated yeast strains were C.albicans (38.6%), C.tropicalis (13.9%), C. parapsilosis (28.4%), C.glabrata (7.4%), C.krusei (3.8%).Conclusion: Recently there is an increment in Candida infections. In this study the most common strain was C.albicans and the rate C. glabrata and C. krusei isolates were lower than expected. C. parapsilosis was the most isolated strain in blood cultures and this may be due to invasive procedures and the use of indwelling catheters.

Phenotypic and genotypic characterization of two closely related subgroups of Candida rugosa in clinical specimens

In this study, six clinical isolates (two from blood, two from urine and one each from a bronchoalveolar lavage and a vaginal swab) were identified as Candida rugosa based on carbohydrate assimilation profiles using API 20C AUX and ID32 C kits (bioMérieux). Sequence analysis of the D1/D2 domain of the yeasts differentiated the isolates into two subgroups, A and B (three isolates per subgroup), which were closely related (99.1-99.6 % nucleotide similarity) to C. rugosa strain ATCC 10571. Compared with the C. rugosa type strain, the intergenic transcribed spacer (ITS) nucleotide similarity for subgroup A was only 89.2 % (29 mismatches and one deletion) and for subgroup B was 93.7 % (20 mismatches). All isolates grew green colonies on Oxoid Chromogenic Candida Agar, with darker pigmentation observed for subgroup A. All isolates were able to grow at 25-42 °C but not at 45 °C. The isolates had identical enzymic profiles, as determined by API ZYM (bioMérieux) analysis, and produced proteinase. High amphotericin MICs (≥1 µg ml(-1)) were noted for two isolates from each subgroup. Dose-dependent susceptibility to fluconazole (MIC 32 µg ml(-1)) was noted in a blood isolate. The biofilms of the isolates demonstrated increased resistance to amphotericin and fluconazole. The greater ITS sequence variability of subgroup A isolates is in support of this yeast being recognized as a distinct species; however, further verification using more sophisticated molecular approaches is required. A sequence comparison study suggested the association of subgroup A with environmental sources and subgroup B with clinical sources. Accurate identification and antifungal susceptibility testing of C. rugosa are important in view of its decreased susceptibility to amphotericin and fluconazole. The ITS region has been shown to be a valuable region for differentiation of closely related subgroups of C. rugosa.

First isolations in India ofCandida nivariensis, a globally emerging opportunistic pathogen

We randomly screened 363 yeast isolates during 2008 for their ability to form white colonies on CHROM agar Candida medium. Two of these isolates (0.5%) were identified as Candida nivariensis based on detailed phenotypic characterization and DNA sequencing. One was recovered from the sputum of an HIV-positive patient with a pneumonic lesion and the second from the blood of a diabetic with oropharyngeal lesions. Direct DNA sequencing of the D1/D2 region of 28S rRNA gene and/or the internal transcribed spacer (ITS) regions of rDNA confirmed that both of the isolates were C. nivariensis. The carbohydrate assimilation profiles with the ID 32 C and VITEK 2 yeast identification systems revealed only glucose assimilation. In vitro antifungal susceptibility profiles by broth microdilution and Etest methods revealed susceptibility of both isolates to fluconazole, itraconazole, voriconazole, amphotericin B and 5-flucytosine, with low MICs for posaconazole and caspofungin. These results document the occurrence of Candida nivariensis for the first time in India and focus on its potential as an opportunistic human pathogen.

First isolations in India of Candida nivariensis, a globally emerging opportunistic pathogen

We randomly screened 363 yeast isolates during 2008 for their ability to form white colonies on CHROM agar Candida medium. Two of these isolates (0.5%) were identified as Candida nivariensis based on detailed phenotypic characterization and DNA sequencing. One was recovered from the sputum of an HIV-positive patient with a pneumonic lesion and the second from the blood of a diabetic with oropharyngeal lesions. Direct DNA sequencing of the D1/D2 region of 28S rRNA gene and/or the internal transcribed spacer (ITS) regions of rDNA confirmed that both of the isolates were C. nivariensis. The carbohydrate assimilation profiles with the ID 32 C and VITEK 2 yeast identification systems revealed only glucose assimilation. In vitro antifungal susceptibility profiles by broth microdilution and Etest methods revealed susceptibility of both isolates to fluconazole, itraconazole, voriconazole, amphotericin B and 5-flucytosine, with low MICs for posaconazole and caspofungin. These results document the occurrence of Candida nivariensis for the first time in India and focus on its potential as an opportunistic human pathogen.

Première identification de Candida dubliniensis au centre hospitalier universitaire Ibn Rochd de Casablanca (Maroc)

Candida dubliniensis is a newly recognized yeast species with phenotypic characteristics closely related to Candida albicans and specifically identified by molecular biology. C. dubliniensis is commonly associated with oral candidiasis, especially in human immunodeficiency virus-positive patients. In this study, the authors describe the first isolates of C. dubliniensis from Morocco and compare phenotypic identification of this species with PCR. For this purpose, 12 C. albicans isolates, taken from hospitalized patients in Ibn Rochd University Hospital of Casablanca (Morocco), were selected for C. dubliniensis confirmation on the basis of their ability to produce abundant chlamydospores on Rice-Agar-Tween (RAT) medium and absence of growth at 45 °C. Presumptive identification of C. dubliniensis was performed using different phenotypic methods: ability to produce chlamydospores on casein agar medium, carbohydrate assimilation profiles and latex agglutination. Final identification was confirmed at the CRMA, Pasteur Institute of Paris, by positive amplification with C. dubliniensis specific primers. Thus, five isolates were confirmed in this study as C. dubliniensis, two were taken from oropharyngeal samples of HIV infected patients, while the remaining three were taken from bronchial aspirations of non-HIV patients.

Species distribution and antifungal susceptibility of Candida bloodstream isolates in Kuwait: a 10-year study

Bloodstream infections due to Candida species are important complications in severely ill hospitalized patients. This study presents data on species distribution and antifungal susceptibility profiles of Candida bloodstream isolates obtained from Kuwait during a 10-year period. All the bloodstream isolates were identified to species level by the germ tube test and carbohydrate assimilation profile using the VITEK 2 yeast identification system. Using E-test strips for amphotericin B, fluconazole, 5-flucytosine and voriconazole, MICs were determined on RPMI agar supplemented with 2% glucose. The MIC breakpoints for resistance were based on Clinical and Laboratory Standards Institute criteria or those published by reference laboratories, and were as follows: amphotericin B, >1 microg ml-1; fluconazole, >or=64 microg ml-1; 5-flucytosine, >or=32 microg ml-1; and voriconazole, 4 microg ml-1. In all, 607 bloodstream yeast isolates were obtained over the past 10 years in Kuwait. Candida albicans was the predominant species (39.5%), followed by Candida parapsilosis (30.6%), Candida tropicalis (12.4%), Candida glabrata (5.6%) and Candida krusei (1.6%). All C. albicans, C. tropicalis and C. glabrata isolates were susceptible to amphotericin B. Of 186 isolates of C. parapsilosis tested, only four (2%) exhibited an MIC for amphotericin B of >1 microg ml-1. Resistance to fluconazole was observed in nine (3.8%) C. albicans isolates, two (5.8%) C. glabrata isolates and four (40%) C. krusei isolates. Resistance to 5-flucytosine was observed in two (0.8%) C. albicans isolates, seven (9.3%) C. tropicalis isolates, three (1.6%) C. parapsilosis isolates and all ten (100%) C. krusei isolates. All the isolates of C. albicans, C. tropicalis, C. parapsilosis, C. glabrata and C. krusei were susceptible to voriconazole, including those resistant to fluconazole. Although amphotericin B and fluconazole are widely used in clinical practice in Kuwait, resistance to these drugs remained low.

Initial Candida dubliniensis isolate in Candida spp. positive haemocultures in Turkey between 2001 and 2004

Candida dubliniensis which was first recognized in 1995 can be easily misidentified because of its phenotypic similarities with Candida albicans. In this study blood samples of patients from various departments of Ankara University Medical Faculty between January 2001-June 2004 were investigated for the distribution of Candida spp. and the presence of C. dubliniensis. Culture positive 67 fungi were included to the study. Phenotypic tests such as chlamydospore formation, colony morphology on Staib agar, growth at 45 degrees C, carbohydrate assimilation profiles were investigated for identification and differentiation of C. dubliniensis from C. albicans. To confirm the results polymerase chain reaction were used for suspected C. albicans and C. dubliniensis isolates. Among 38 germ tube and chlamydospore forming isolates, 37 of them were found as C. albicans and one as C. dubliniensis. The incidence of C. dubliniensis in our hospital is still low, this is the first C. dubliniensis isolate as an agent of candidaemia reported from Turkey.

Characterization of Switch Phenotypes in Candida albicans Biofilms

The aim of this study was to characterize switch phenotypes in Candida albicans biofilms. Cells of Candida albicans 192887g biofilms (24 h) were resuspended and these together with their planktonic counterparts were separately inoculated on Lee's medium agar supplemented with arginine and zinc, at 25 degrees C for 9 days, for colony formation. The different switch phenotypes, as reflected by varying colony morphologies, were then examined for their (i) stability under various growth conditions, (ii) carbohydrate assimilation profiles, (iii) susceptibility to the polyene antifungal, nystatin, (iv) adhering and biofilm-forming ability, (v) filamentation, and (vi) growth rate in yeast nitrogen base medium supplemented with 100 mM glucose. Our data showed that the frequency of phenotypic switching in C. albicans biofilms was approximately 1%. Compared with the planktonic yeasts, cells derived from candidal biofilms generated one of the phenotypes less frequently (Chi-square-tests: P = 0.017). The five phenotypes derived from the biofilm growth demonstrated differing profiles for carbohydrate assimilation, adhesion, biofilm formation, filamentation, and growth rate. These findings reported here, for the first time, imply that phenotypic switching in the candidal biofilms differs from that in the planktonic growth, and affects multiple biological attributes.

Detection of Candida dubliniensis in oropharyngeal samples of Turkish HIV‐positive patients

The incidence of Candida dubliniensis in immunocomprimised patients in Turkey has not yet been determined. In this study the presence of C. dubliniensis in oral rinse samples of human immunodeficiency virus (HIV)-positive patients and healthy controls were investigated. Phenotypic tests like inability of growth at 45 degrees C, colony formation on Staib agar, intracellular beta-D-glucosidase activity, carbohydrate assimilation profiles and polymerase chain reaction with species-specific primers (DUBF and DUBR) were carried out for differentiation of C. dubliniensis. Of the 35 patients, four (11.4%) had C.dubliniensis in their oral cavity. Antifungal susceptibility testing of these C. dubliniensis isolates showed fluconazole MICs ranging from <0.06 to 32 microg ml(-1) and amphotericin B from <0.06 to 0.25 microg ml(-1). One isolate was dose-dependently susceptible to fluconazole (32 microg ml(-1)). This study demonstrates C. dubliniensis in HIV-positive patients from Turkey.

Carbohydrate assimilation profiles of Brazilian Candida dubliniensis isolates based on ID 32C system

The purpose of the present study was to evaluate the identification of 19 Brazilian C. dubliniensis based on the biochemical profile exhibited when tested by the commercial identification kit ID 32C (bioMerieux). Thirteen of the isolates were rigorously identified as C. dubliniensis and the remaining isolates (six) were considered as having a doubtful profile but the software also suggested that there was 83.6% of chances for them to be C. dubliniensis. As well as pointed by the literature the identification obtained by phenotypic tests should be considered presumptive for C. dubliniensis due to variability of this new species.