Original Research Article (Experimental): Targeting fungal menace through copper nanoparticles and Tamrajal

WHO reports, an escalation of antibiotic resistance in opportunistic pathogens like Candida. Tamrajal, i.e., water stored in copper vessels has been proclaimed as health elixir by ancient Ayurveda. Vis-a-Vis the use of copper contact surfaces and nanoparticles has gained significance for their antimicrobial effects. It thus seems imperative to examine copper nanoparticles and tamrajal as promising alternatives to existing antifungals.ObjectiveThis study not only assessed the influence of Tamrajal and copper nanoparticles on the morphological alterations of the Candida and its biofilm forming ability, but also on their ability to destroy preformed biofilms.Materials and methodsCopper oxide nanoparticles as well as Tamrajal were evaluated as complementary as well as stand-alone antimicrobial agents. ‘Time kill assay’ and ‘germ tube inhibition test’ were performed as end-point analysis for pathogenesis, while biofilm quantification, performed to assess the colonizing capability of Candida. Scanning Electron Microscope was used for visualizing the cells, whilst ICP-AES to determine the copper concentration.Results92–100% cytotoxicity to the fluconazole resistant Candida species was observed with copper oxide nanoparticles as well as tamrajal during 24hr time kill assay. The study also confirmed complete germ tube inhibition by copper in both its forms in addition to the reduction in the biofilm production.ConclusionCompared to the classes of antifungals like azoles, echinocandins etc, copper based anti-candidal agents highlight a potential way to combat resistant candidiasis. The possibility of accumulation of NP resulting in cytotoxicity puts tamrajal as the choice due to its efficacy as well as non-toxicity as per the EPA.

Satureja khuzistanica Jamzad essential oil and its anti-candidal activities against clinical isolates of Candida albicans isolated from women with candidiasis / Actividad anti-Candida de los aceites esenciales del Jamzad Satureja khuzistanica contra aislados clínicos de Candida albicans obtenidos de mujeres con candidiasis

Satureja khuzistanica Jamzad is known as antiseptic and analgesic agent in folk medicine. The aim of this investigation was to evaluate the anti-candidal activity of S. khuzistanica aerial parts essential oil against clinical isolates of Candida albicans, which were isolated from women with chronic recurrent candidiasis. For this purpose, the chemical composition of hydro-distilled essential oil was determined by GC and GC-MS analysis. Then, the anti-candidal activity of essential oil and its main component (carvacrol) were determined. Carvacrol (94.1%) was the main component of essential oil, followed by β-bisabolene, p-cymene and γ-terpinene. S. khuzistanica essential oil had strong anti-candidal activity against clinical isolates of C. albicans via inhibition of germ tube formation and induction the huge punctures in the cytoplasmic structures. The cell membranes were intact in presence of essential oil or carvacrol. S. khuzistanica essential oil as the main source of carvacrol can be used for treatment of C. albicans related infections.

Satureja khuzistanica Jamzad es conocido como analgésico y antiséptico en la medicina tradicional. El objetivo de esta investigación fue evaluar el efecto anti- Candida de los aceites esenciales obtenidos de las partes aéreas de S. khuzistanica sobre aislados clínicos de Candida albicans, obtenidos de mujeres con candida diasis crónica recurrente. Para este propósito la composición química de aceites esenciales hidrodestilados fueron determinados por análisis GC y GC-MS. Luego la actividad anti-candidasica de los aceites esenciales y de su componente principal (carvacrol) fue determiando. Carvacrol (94.1%) fue el principal compuesto del aceite esencial seguido por β-bisaboleno, p-cimeno and γ-terpineno. El aceite esencial de S. khuzistanica tuvo fuerte actividad anti-candida contra aislados clínicos de C. albicans via la inhibicion de tubo germinal y la inducción de estructuras puntiformes en la membrana citoplásmatica. Las membranas celulares quedaron intactas en presencia del aceite esencial o del carvacrol. El aceite esencial de S. khuzistanica como fuente principal de carvacrol podría ser usado como tratamiento de infecciones relacionadas con Candida albicans.

Antifungal activity of some Sternbergia taxa: effects on germ tube and biofilm formation

Natural products are rapidly becoming the primary sources of novel antimicrobial agents, as resistance to existing antimicrobial agents is increasing. Apart from determining the antimicrobial activity of natural products, it is also important to understand their effects on the virulence factors of microorganisms. This study aimed to determine the antimicrobial activity of Sternbergia species prevalent in Turkey and investigate their role in the inhibition of germination tube and biofilm formation, both of which are known to be important virulence factors of Candida albicans. The antimicrobial activities of the plant extracts were evaluated using bore-plate and broth microdilution method. The extracts' capacity to inhibit the formation of the germ-tube was also evaluated. The findings of our study revealed that Sternbergia lutea, Sternbergia vernalis possessed antimicrobial activities, with MIC values ranging between 0.048 mg/mL and 0.39 mg/mL. The highest antimicrobial activity was observed against Candida dubliniensis (0.048 mg/mL). While evaluating the inhibition of fungal germination activities, S. vernalis extract (at a concentration of 0.09 mg/mL) was found to be the most effective against C. albicans ATCC 90028 strain. The results also indicated that S. vernalis extracts at sub-MIC levels inhibited germ tube formation and modulated the tail-length of germinated cells, both of which are important virulence factors of C. albicans. Furthermore, the inhibition of biofilm-formation was also investigated, and it was found that two Sternbergia spp. extracts at or below MIC levels inhibited biofilm formation.

Comparison between four usual methods of identification of candida species / Comparação entre quatro métodos usuais de identificação de espécies de Candida

SUMMARYInfection by Candidaspp. is associated with high mortality rates, especially when treatment is not appropriate and/or not immediate. Therefore, it is necessary to correctly identify the genus and species of Candida. The aim of this study was to compare the identification of 89 samples of Candidaspp. by the manual methods germ tube test, auxanogram and chromogenic medium in relation to the ID 32C automated method. The concordances between the methods in ascending order, measured by the Kappa index were: ID 32C with CHROMagar Candida(κ = 0.38), ID 32C with auxanogram (κ = 0.59) and ID 32C with germ tube (κ = 0.9). One of the species identified in this study was C. tropicalis,which demonstrated a sensitivity of 46.2%, a specificity of 95.2%, PPV of 80%, NPV of 81.1%, and an accuracy of 80.9% in tests performed with CHROMagar Candida;and a sensitivity of 76.9%, a specificity of 96.8%, PPV of 90.9%, NPV of 91%, and an accuracy of 91% in the auxanogram tests. Therefore, it is necessary to know the advantages and limitations of methods to choose the best combination between them for a fast and correct identification of Candidaspecies.

RESUMOA infecção por Candidaspp. está associada com alta mortalidade, principalmente quando o tratamento não é adequado, nem imediato. Assim, a correta identificação do gênero e espécie é necessária. O objetivo deste trabalho foi comparar 89 amostras de Candidaspp. pelos métodos manuais prova do tubo germinativo, auxanograma e CHROMagar em relação ao método automatizado ID 32C. As concordâncias entre os métodos em ordem crescente, medidas pelo coeficiente de Kappa, foram: ID 32C com CHROMagar Candida(κ = 0,38), ID 32C com auxanograma (κ = 0,59) e ID 32C com tubo germinativo (κ = 0,9). Uma das espécies identificadas neste trabalho foi a C. tropicalis, que demonstrou uma sensibilidade de 46,2%, especificidade de 95,2%, VPP de 80%, VPN de 81,1% e acurácia de 80,9% nos testes com CHROMagar Candidae uma sensibilidade de 76,9%, especificidade de 96,8%, VPP de 90,9%, VPN de 91% e acurácia de 91% nos testes de auxanograma. Portanto, o conhecimento das vantagens e limitações dos métodos é necessário para a escolha da melhor combinação entre os mesmos visando uma rápida e correta identificação das espécies de Candida.

Use of mueller-iinton broth and agar in the germ tue test / Utilização de ágar e caldo Mueller-Hinton na prova do tubo germinativo

Candida albicans is often isolated from clinical samples, thus its presumptive differentiation from other species of the same genus can be based on its ability to form the germ tube in human serum. Nevertheless, there are two other species that share this characteristic: C. dubliniensis and C. africana. The aim of this study was to compare four different substrates to perform the germ tube (GT) test. The Candida spp. isolates were identified using a manual system (135 C. albicans, 24 C. tropicalis and one C. dubliniensis). The germ tube test was performed with fresh, previously frozen serum and Mueller-Hinton (MH) broth and agar. GT was observed in 96% (130/136) of the isolates through the fresh serum technique, 94% (128/136) through previously frozen serum, 92% (125/136) in MH agar, and 90% (122/136) in MH broth. The sensitivity of each test was higher than 90%, with 100% specificity. Both the MH agar and broth were able to identify the true positives, and false positives were not found. However, some C. albicans isolates were not identified. MH agar and broth may be used in laboratory for the rapid presumptive identification of C. albicans, as an alternative method for germ tube test.

Candida albicans é frequentemente isolada em amostras clínicas, assim a sua diferenciação presuntiva de outras espécies do gênero pode ser baseada na habilidade em formar o tubo germinativo em soro humano. Entretanto, existem outras duas espécies que também possuem essa característica, C. dubliniensis e C. africana. O objetivo foi comparar quatro diferentes substratos para a realização da prova do tubo germinativo (TG). Utilizou-se isolados de Candida spp. identificados através de meio manual (135 C. albicans, 24 C. tropicalis e um C. dubliniensis). A prova do tubo germinativo foi realizada utilizando soro previamente congelado e fresco, caldo e ágar Mueller-Hinton (MH). O TG através da técnica do soro a fresco foi observado em 96% (130/136), 94% (128/136) através do soro previamente congelado, 92% (125/136) no ágar e 90% (122/136) no caldo MH. A sensibilidade de cada teste foi maior que 90% e especificidade de 100%. Tanto o caldo quanto o ágar MH foram capazes de identificar apenas os verdadeiros positivos e não ocorrendo falsos positivos, porém deixaram de identificar alguns isolados de C. albicans. O ágar e o caldo MH podem ser utilizados na rápida e presuntiva identificação laboratorial de C. albicans, como uma alternativa para o teste do tubo germinativo.

Treatment with some anti-inflammatory drugs reduces germ tube formation in Candida albicans strains

Candida albicans is an opportunistic dimorphic fungus that inhabits various host mucosal sites. It can cause both superficial and serious systemic disease. Conversion from the yeast to the hyphal form has been associated with increased virulence and mucosal invasiveness. The aim of this study was to investigate the effect of sodium diclofenac and aspirin on germs tube formation of different Candida albicans strains. Prostaglandins may play an important role in fungal colonization. Nonsteroidal anti-inflammatory drugs are inhibitors of the cyclooxygenase isoenzymes. These drugs specifically block the biosynthesis of mammalian prostaglandins by inhibiting one or both of cyclooxygenase isoenzymes. In tests for germ tube formation sodium diclofenac reduced the filamentation to the 12.5%- 5.1%. In the presence of aspirin the filamentation was reduced up to 85-45% depending on the tested strain. Our results suggest that cyclooxygenase-depending synthesis of fungal prostaglandins is important for morphogenesis and fungal virulence. Inhibitors of cyclooxygenase isoensymes (aspirin and diclofenac) are effective in decreasing germ tube formation of Candida albicans.

Determination of germ tube, phospholipase, and proteinase production by bloodstream isolates of Candida albicans

Introduction Candida albicans is a commensal and opportunistic agent that causes infection in immunocompromised individuals. Several attributes contribute to the virulence and pathogenicity of this yeast, including the production of germ tubes (GTs) and extracellular hydrolytic enzymes, particularly phospholipase and proteinase. This study aimed to investigate GT production and phospholipase and proteinase activities in bloodstream isolates of C. albicans. Methods One hundred fifty-three C. albicans isolates were obtained from blood samples and analyzed for GT, phospholipase, and proteinase production. The assays were performed in duplicate in egg yolk medium containing bovine serum albumin and human serum. Results Detectable amounts of proteinase were produced by 97% of the isolates, and 78% of the isolates produced phospholipase. GTs were produced by 95% of the isolates. A majority of the isolates exhibited low levels of phospholipase production and high levels of proteinase production. Conclusions Bloodstream isolates of C. albicans produce virulence factors such as GT and hydrolytic enzymes that enable them to cause infection under favorable conditions. .

Comparison of germ tube production by candida albicans in various media.

Introduction: Candidiasis is one of the important opportunistic fungal infections in human. Candida albicans (C.albicans) is the predominant Candida species isolated from clinical samples. In routine laboratory, C.albicans is diagnosed on the basis of culture, staining morphology, germ tube production, & chlamydospore formation on cornmeal agar. The objective of this study was to assess the reliability of different media for germ tube production. Material & Methods: The study was carried out on various clinical samples received in Microbiology department of M.P.Shah medical college, Jamnagar from January to July 2011. Among all clinical samples, 100 isolates of C.albicans were compared for germ tube production in 4 different media (sterile horse serum, pooled human serum, trypticase soy broth and Brain heart infusion (BHI) broth. Candida species were also identified by using culture, staining morphology, & chlamydospore formation on cornmeal agar. Results: In our study, among 100 C.albicans isolates, sterile horse serum gave 100% germ tube production, pooled human serum gave 93%, BHI gave 63% and trypticase soy broth gave 60% germ tube production at the end of 2 hours of incubation. Conclusion: This study shows that sterile horse serum is best medium for germ tube production of C.albicans and it can replace human serum which has its disadvantage in being bio hazardous with false negative reporting.

Unusual morphologies of Cryptococcus spp. in tissue specimens: report of 10 cases / Histopatologia, sorologia e cultivo no diagnóstico da criptococose

Ten cases of cryptococcosis due to unusual microscopic forms of Cryptococcus sp. observed over a twenty-eight year period (1981-2009) are presented. The most important clinicopathological and laboratory data are tabulated. The uncommon forms of cryptococcal cells given are: structures resembling germ tube (one case), chains of budding yeasts (one case), pseudohyphae (two cases) and nonencapsulated yeast-like organisms (eight cases). The diagnosis was based on the histopathological findings. The causative organism was isolated and identified in seven cases; five were due to C. neoformans, and two to C. gattii. In addition, the importance of using staining histochemical techniques - Grocott's silver stain (GMS), Mayer's mucicarmine stain (MM) and Fontana-Masson stain (FM) - in the diagnosis of cryptococcosis is argued.

A criptococose é a mais comum infecção fúngica oportunística observada em pacientes com síndrome da imunodeficiência adquirida (AIDS). Relatamos 13 casos da infecção baseados no diagnóstico histopatológico, sorológico e cultivo. Foram analisadas: a epidemiologia, as técnicas histoquímicas básicas de hematoxilina-eosina (HE) e coloração pela prata (GMS), bem como as técnicas histoquímicas especiais de mucicarmim de Mayer (MM) e Fontana-Masson (FM), o teste do antígeno criptocóccico (CrAg) e o isolamento em cultivos em ágar-Sabouraud (SAB), ágar infusão de cérebro-coração (BHI) e meio com canavanina azul de bromotimol (CGB). Em quatro casos, resultados tintoriais insatisfatórios pela coloração de MM associados a títulos negativos pelo teste do CrAg, a coloração de FM confirmou a infecção pelo Cryptococcus deficiente de cápsula. Oito isolados foram identificados: seis casos apresentaram a infecção por Cryptococcus neoformans e dois casos apresentaram a infecção por Cryptococcus gattii.

Atividade hemolítica e produção de tubos germinativos relacionados ao potencial patogênico de isolados clínicos de Candida albicans / Hemolytic activity and production of germ tubes related to pathogenic potential of clinical isolates of Candida albicans

We assessed the virulence factor profile and in vitro antifungal susceptibility of 27 hospital isolates of C. albicans; 19 of these were from infections (16 urinary and three blood), and the other eight were isolated from sites of colonization (two from hands of health professionals, and six from central venous catheters). The virulence factors assayed were germ tube formation and production of extracellular products (hemolysins, proteinases, and phospholipases). Susceptibility to fluconazole, itraconazole, voriconazole and amphotericin B was determined by E-test. Regarding the virulence factors, the infection isolates produced significantly more hemolysin and germ tubes than the colonization isolates (p<0.05). There were no significant differences in the production of other factors between isolates from the two sources (p>0.05). Amphotericin B showed the lowest minimum inhibitory concentrations for all the isolates. The highest resistance was observed for the azoles, especially in the clinical isolates. These results suggest that the capacity of C. albicans to produce hemolysins and germ tubes may be associated with its pathogenic potential. Colonization isolates may pose a high risk of nosocomial infection, especially when the yeasts show resistance to antifungals.

O perfil de virulência e o de susceptibilidade in vitro aos antifúngicos de 27 amostras de C. albicans de origem hospitalar foi avaliado, sendo que 19 delas foram isoladas de infecções (16 urinárias e três sanguíneas) e as outras oito foram isoladas de colonização (duas de mãos de profissionais da saúde e seis de cateter venoso central). Os seguintes fatores de virulência foram investigados: formação de tubo germinativo e produção de compostos extracelulares (hemolisinas, proteinases e fosfolipases). Suscetibilidade ao fluconazol, itraconazol, voriconazol e anfotericina B foram determinadas por E-test. Em relação aos fatores de virulência, os isolados de infecção produziram significativamente mais hemolisina e tubos germinativos do que os de colonização (p<0.05). Não houve diferença significativa na produção das outras enzimas, entre os isolados das duas fontes (p>0.05). Anfotericina B mostrou as menores concentrações inibitórias mínimas para todos os isolados. Maiores índices de resistência foram observados aos azólicos, especialmente entre os isolados clínicos. Estes resultados sugerem que a capacidade de C. albicans produzir hemolisinas e tubos germinativos pode estar associada com seu potencial patogênico. Por outro lado, leveduras em colonização podem oferecer alto risco para infecção hospitalar, especialmente quando têm perfil de resistência aos antifúngicos.

Modalidades de la Prueba del Tubo Germinal / Modalities of the Germ Tube Test

Las infecciones por levaduras del género Candida, en la actualidad son cada vez más frecuentes, particularmente cuando se presentan condiciones que inmunosuprimen al paciente, como el Síndrome de Inmunodeficiencia Adquirida y el uso de quimioterápicos e inmunomoduladores, entre otros. Candida albicans es la especie del género que se aísla con mayor frecuencia. Entre las pruebas de identificación para las especies de levaduras del género Candida se encuentran la evaluación de las características macroscópicas de las colonias, pruebas físiológicas, como la prueba del tubo germinal, termotolerancia, auxanograma, zimograma, ureasa y resistencia a la cicloheximida, entre otras. De estas, la prueba del tubo germinal es una prueba sencilla y rápida que puede ejecutarse de varias formas. De manera tradicional se ha realizado en tubo y con suero, aunque también se puede realizar en placa. En este trabajo se revisan las diversas formas de realizar esta prueba y se describe una modalidad adicional, producto de la experiencia diaria en el trabajo de laboratorio, con la ventaja del ahorro de material de vidrio y tiempo.

At the present time, the infections by yeasts of the genera Candida, are more and more frequent, particularly when exists inmunosuprimen conditions, like the Acquired Immunodeficiency Syndrome, the use of quimioterapics and inmunomodulators, among others. Candida albicans is the species most frequently isolated from clinical samples. Among the identification tests of the yeasts species of the genera Candida are the evaluation of colony characteristics, physiological and biochemical tests like the germ tube, termotolerancy, auxonogram, zimogram, urease, resistance to cicloheximide, among others. The germ tube test is a simple and fast test, of which several forms exist to carry out it. The traditional way has been made in tube, with serum, although it´s possible to be made in plate. Here we present the modality to directly make the test of the germ tube between slide and slide cover, with advantage of time saving and glass material saving.

Appropriate Condition of Germ Tube Formation as Presumptive Identification Test for Candida albicans / 대한의진균학회지

BACKGROUND: Candida albicans is the most prevalent species found in human yeast infections. The germ tube test is still frequently used for its rapid presumptive identification. Recently Candida dubliniensis as well as C. albicans has been reported to form germ tubes. OBJECTIVE: The purpose of this study was to evaluate the germ tube test at various conditions for rapid presumptive identification of C. albicans. METHODS: C. albicans ATCC 14053, C. albicans ATCC 18804, C. dubliniensis ATCC MYA 646, and C. dubliniensis KCTC 17427 were tested. Human pooled serum (HPS), HBV, HCV infected patient serum, fetal bovine serum (FBS) and rabbit serum (RS) were used for germ tube test. The germ tube formation was evaluated at different keeping condition of various sera, after mixing with 5 different bacterial suspensions and at various incubation conditions. RESULTS: The germ tube formation of C. albicans was more in the RS or FBS than in the HPS. For the various sera fresh sample was always the best expression of germ-tube forming ability. In the HCV infected patient serum and mixing with Pseudomonas aeruginosa germ tube formation was suppressed. C. dubliniensis did not form germ tube in the HPS, only formed in the FBS or RS. CONCLUSION: For rapid presumptive identification of C. albicans not C. dubliniensis the best selection of serum is the fresh HPS. We recommend the examination with isolated colony free from bacteria after incubation for 2 to 3 hours.

Rapid Identification of Candida albicans by 'Spiking' on Blood and Chocolate Agar Plates / 대한임상미생물학회지

BACKGROUND: Colonial morphology of Candida albicans known as 'spiking' on a primary isolation blood agar plate (BAP) allows rapid and presumptive identification of C. albicans. We evaluated the 'spiking' appearance to identify C. albicans. METHODS: A total of 144 fully identified clinical isolates of yeasts and 10 type strains of yeasts were tested. All isolates obtained from the 5% CO2 incubation on BAP and chocolate agar plate (CHOC) were macroscopically examined for the presence of an irregular margin (spiking). The germ tube test was performed by incubating test organisms in 0.5 mL of pooled human sera. RESULTS: The sensitivity for BAP-spiking, CHOC-spiking and germ tube test were 93.7%, 91.1%, and 98.7%, respectively. The specificity for three methods was 100%. CONCLUSION: Use of the spiking identification on BAP can be useful for the economic and rapid presumptive identification of C. albicans in routine laboratories.

Search for Genes Potentially Related to Germ Tube Formation in Candida albicans by Differential-Display Reverse Transcription Polymerase Chain Reaction

Candida albicans exhibits the ability to grow in either a yeast or a mycelia form in response to different environmental factors. The mycelia form, found in infected tissues, is important as a virulence factor in the adherence of the organism to the host epithelium. In vitro, the morphological transition can be induced by environmental shifts in the growing conditions, or by a variety of exogenous factors, including ambient pH, nutritional status and temperature. The differential-display reverse transcription polymerase chain reaction (DDRT-PCR) is a powerful technique for comparing gene expression between cell types, stages of development or differentiation. Hyphae related genes were identified and characterized using a PCR-based differential display. Candida albicans formed a germ tube when cultured in rabbit serum, RPMI 1640 medium or 39degrees C-YPD medium. We gained 21 cDNA bands showing a different expression pattern from that of the uninduced culture. DNA was extracted from the same location of the isolated bands, and PCR was performed under the same conditions, which reamplified the PCR product, showing the specific expression patterns according to the culture conditions. We cloned 18 germ tube-related cDNA clones (inserts average size is 80 - 700 bp) and sequenced them. The nucleotide sequences of the 18 clones were identified through in the present study from GenBank, and were found to have the accession number (AF405213-AF405230). We could not find any nucleotide sequence having a high homology with these clones. This study could form a part of the projects in the search for genes related to the germ tube formation of C. albicans.

Characterization of target antigen of new monoclonal antibody 03.2C1-C2 specific for Candida albicans germ tube / 第三军医大学学报

Objective To analyze the characterization of the target antigen of the monoclonal antibody(Mab) 03.2C1-C2 against germ tube of Candida albicans,and explore the possibility of Mab03.2C1-C2 application in the laboratory examination.Methods SDS-PAGE and Western blotting were used to analyse the molecular weight of antigens recognized by Mab03.2C1-C2.The distribution of the target antigens on the surface of the germ tube induced in vitro were analyzed.The epitope of the target antigen were analysed via indirect immunofluorescence(IIF).Results The target antigen recognized by Mab03.2C1-C2 could be detected 30 min after the germ tube formation.The distribution of the target antigens were different between the germ tube formated in vitro and in vivo.The epitope might locate in the N-carbohydrate chain.Conclusion New protein-glycoprotein that is the target antigen of Mab03.2C1-C2 was produced during the formation of the C.albicans germ tube.Strong antigenicity of glycoprotein is of certain value on quick diagnosis of Systemic C.albicans.

Comparison of Murex Candida albicans CA50 with the Germ Tube Test for Presumptive Identification of Candida albicans / 대한임상병리학회지

BACKGROUND: Rapid and reliable identification of Candida albicans becomes more important because the incidence of yeast infections has increased in recent years. Murex C. albicans 50(CA50) assay was developed for rapid and presumptive identification of C. albicans. We evaluated the CA50 assay to identify C. albicans. METHOD: Seventy four yeast isolates from clinical specimens were tested with CA50 and germ tube test. They were identified to species level by API 20C and chlamydospore agar test. RESULT: Of the 74 isolates, 52 were C. albicans and 22 were non-albicans Candida. The sensitivity and specificity for CA50 were 88.5% and 86.4%, respectively. The sensitivity and specificity of the germ tube test using human serum were 88.5% and 90.9% respectively, and those using fetal bovine serum(FBS) were 92.3% and 90.9% respectively. CONCLUSION: CA50 was a rapid and easy-to-perform test, and it was comparable to germ tube test in regard of sensitivity and specificity.

The presumptive identification of Candida albicans with germ tube induced by high temperature

For direct identification of Candida albicans from other Candida species, the chlamydospore formation and the mycelial transition induced by high temperature and by sera were examined in 198 Candida isolates. The germ tubes of C. albicans developed early at 30 min in high temperature-induction, but at 60 min in serum-induction. C. albicans generated germ tubes well at concentrations lower than 2 x 10(7) cells/ml, but the germ tube formation was markedly restrained at concentrations higher than 4 x 10(7) cells/ml. In a serum-free, yeast extract-peptone-dextrose (YEPD) medium, C. albicans grew as a yeast form at 30 degrees C and as a mycelial form at 35-42 degrees C. Mycelial development was maximal at 37 degrees C in serum and at 39 degrees C in YEPD. Germ tubes were formed within 30 min in YEPD at 39 degrees C, but after 60 min in serum at 37 degrees C. Our examination showed that the 39 degrees C-induced germ tube formation tests were very reliable (sensitivity 100%, specificity 100%) at discerning C. albicans from other Candida species. These results suggest that the high temperature-induced germ tube formation testing could be a useful identification method of C. albicans in clinical laboratories.