Germ Tube Production Research Articles

Microscopic Characterization of the Infectious Process, ROS Production, and Fungi Cellular Death of Alternaria alternata on Tangerine Resistant to QoIs.

Quinone outside inhibitor (QoI) fungicide resistance in Alternaria alternata populations was reported in Brazil for the first time in 2019, in São Paulo orchards, and the mutation G143A in cytochrome b (cytb) was found in resistant isolates. Our study investigated the infectious process, production of reactive oxygen species (ROS), and fungal cell death in resistant (QoI-R) and sensitive (QoI-S) A. alternata pathotype tangerine (Aapt) isolates. Morphological characterization of Aapt isolates was performed using confocal laser scanning microscopy (CLSM). Alternaria brown spot (ABS) symptoms were produced by Aapt isolates on tangelo cv. BRS Piemonte. Germination of QoI-R conidia and production of germ tubes on tangelo leaflets treated with 100 μg mL-1 of pyraclostrobin 18 h after inoculation (hai) was observed using scanning electron microscopy (SEM). At the same time, QoI-S conidial germination was inhibited on tangelo leaflets treated with pyraclostrobin. ROS production and cell death in Aapt isolates at high fungicide concentrations were observed using CLSM. QoI-S conidia exhibited high ROS production, indicating high oxidative stress. When dyed with propidium iodate (PI), QoI-S conidia emitted red fluorescence, showing cell death and confirming their sensitive phenotype. In contrast, QoI-R conidia neither produced ROS nor exhibited red fluorescence, indicating no cell death and confirming their resistant phenotype. Therefore, our findings evidence that microscopic techniques may help characterize events during fungi-plant interactions, ROS production, cell death, and Aapt phenotypes resistant and sensitive to QoIs using fluorometric protocols.

Rumex japonicus Houtt. Leaves: the chemical composition and anti-fungal activity

BackgroundCandida albicans is a pathogenic commensal fungus. Trichophyton mentagrophytes and Trichophyton rubrum are the leading pathogens of dermatophysis. Rumex japonicus Houtt. has a miraculous effect on the treatment of tinea skin disease, but its mechanism has not been clarified. Purpose: This paper investigated the anti-fungal ingredients of the leaves of Rumex japonicus Houtt. (RJH-L) and the mechanism of the anti-fungal (Trichophyton mentagrophytes, Trichophyton rubrum and Candida albicans). MethodFirst, the chemical composition analysis of RJH-L was conducted by acid extraction and alcohol precipitation, high performance liquid chromatography (HPLC) and nuclear magnetic resonance spectroscopy (NMR); in vitro anti-fungal experiments were carried out, including the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) spore germination rate, germ tube production rate, nucleic acid and protein leakage rate, biofilm structure, PCR, etc., to study the mechanism of action of RJH-L anti-fungal and anti-biofilm activity. ResultSeven monomer compounds were obtained: anthraquinones (rhein, emodin and aloe-emodin); polyphenols (ferulic acid, p-coumaric acid), and flavonoids (rutin and quercetin). The results of in vitro anti-fungal experiments showed that the extracts of RJH-L had strong inhibitory effect on both fungi (MIC: 1.96 µg/mL-62.50 µg/mL), of which emodin had the strongest effect on Trichophyton mentagrophytes; and rhein had the strongest effect on Candida albicans and Trichophyton rubrum. The above active components can inhibit the germination of fungal spores and germ tube, change cell membrane permeability, prevent hyphal growth, destroy the biofilm structure, and down-regulate the expression of agglutinin-like sequencefamily1 of biofilm growth. ConclusionThis study shows that RJH-L are rich in polyphenols, flavonoids, and anthraquinones, and play a fungicidal role.

Lupeol a predisposing factor in grey mould (Amphobotrys ricini [N.F. Buchw.]) Hennebert disease pathogenesis in castor (Ricinus communis L.)

AbstractTo understand the castor wax layer's multifaceted contribution to Amphobotrys ricini pathogenesis, the hydrophobic components of cuticular wax were analysed from waxy and non‐waxy castor genotypes. Gas chromatography–mass spectrometry (GC–MS) technology enabled the stable detection and quantitative determination of various fatty acids and terpenoids. The investigation revealed a significant presence of triterpenoid compound ‘lupeol’, accounting for approximately 53.6% of the wax composition in the waxy genotype (DCH‐519), which was absent in non‐waxy genotype (ICS‐324). On exposure to lupeol, about 93.3% of conidia germinated leading to rapid mycelium growth and sporulation of A. ricini. SEM analysis of waxy and non‐waxy genotypes infected with A. ricini confirmed faster germination and production of longer germ tubes on waxy genotype compared with non‐waxy genotype, which may likely due to early recognition of the suitable host in the presence of lupeol, ultimately aiding in speedy germination and growth of the pathogen setting pace for pathogenesis.

الكشف عن بعض عوامل الضراوة بين المبيضات المعزولة من المرضى وانتشار جين candidalysin ECE1

المبيضات البيضاء هي مسبب شائع لعدوى الجهاز التنفسي وداء المبيضات الفموي لدى الناس ، ومسببات أمراض الخميرة الانتهازية والأسباب الرئيسية للمرض والوفيات لدى الأشخاص الذين يعانون من نقص المناعة وتسبب التهابات سطحية على الأسطح المخاطية التي تصيب ملايين الأشخاص في جميع أنحاء العالم. كان الهدف الرئيسي من هذه الدراسة هو التحقق من انتشار بعض عوامل الضراوة التي لها القدرة على تكوين الأغشية الحيوية (Biofilm)، والبروتينيز (Proteinase)، وإنتاج الهيمولايسين( Hymolysine) بين عزلات C. albicans التي تشمل انتشار جين Candidalysin (ECE1). تم جمع العينات خلال الفترة من ايار 2022 الى اب 2022 من 280 عينة (مسحة) لمرضى عراقيين من مختلف الاعمار والاجناس غير مكررين كانوا يعانون من داء المبيضات الفموي وامراض الجهاز التنفسي في مستشفيات بغداد (مستشفى مدينه الطب و مستشفى اليرموك التعليمي ومستشفى مدينه الامامين الطبية التعليمية). تم زراعة العينات التي تم جمعها على وسط اكار السابرويد دكستروز (SDA) مضاف اليه كلورامفينيكول كمضاد للبكتيريا بتركيز 10 ميكجم / مل ، وتم حضن الاطباق الملقحة على وسط SDA عند 37 درجة مئوية لمدة تتراوح بين 24-48 ساعة.أظهرت نتائج الاستنبات أن 102 عينة كانت موجبه، منها58 (56.86%) من تجويف الفم و 44 (43.14%) من الجهاز التنفسي، بينما 178 منها كانت سالبة , تم الكشف عن عزلات المبيضات باستخدام الطرق التقليدية والتي تشمل (النمو على وسط HiCrome Candida ، إنتاج الأنبوب الجرثومي Germ tube ، تكوين الابواغ الكلاميديه Clamydospore وتم تأكيد نتئج التعريف باستخدام نضام VITEK-2 بينت النتائج ان من بين 102 عزلة C. albicans هي الاكثر شيوعا بين الانواع بنسبة 68.63 % ثم تلتها C. tropicalis بنسبة %10.78 ثم C. kruzei %5.88 وC. kefyr %5.88 C. parapsilosis % 4.9 بينما كانت C. glabrata % 3.9 وتمثل النسبة الاقل بين الانواع . تم فحص حساسية عزلات المبيضات للأدوية المضادة للفطريات بطريقة انتشار القرص ، والتي أجريت على النحو الموصى به بواسطة(CLSI) M44-A -وثيقة . أظهرت العزلات درجة عالية من الحساسية للأمفوتريسين-ب 93.14% وكلوتريمازول 90.20% ونسياتين 85.92% ،تم التحقق من انتشار جينCandidalysin (ECE1) بين 70 عزلة من C. albicans باستخدام تقنية تفاعل البلمرة المتسلسل PCR ، وأظهرت النتائج أن 41 58.57% تحتوي على جين Ece1 في تجويف الفم والجهاز التنفسي. و 34 عزلة 48.57% من C. albicans كانت منتجة قوية للغشاء الحيوي, بينما 30 عزلة 42.86% عزلة انتجت بروتيناز و 20 عزلة 28.57% عزلة لديها القدرة على تحلل الدم.

Oral Rinses: Some Kill and Some Cripple Candida albicans

Introduction: Oral healthcare professionals play a crucial role in guiding patients toward evidence-based choices among the many available oral rinses. In this study, we explored how specific oral rinse formulations affect the viability and modulate critical virulence traits of the opportunistic fungal pathogen Candida albicans. Materials and Methods: We assessed the effects of these oral rinses on the production of germ tube, production of phospholipase and hemolysin, as well as biofilm formation. Results: We found that oral rinses containing cetylpyridinium chloride (CPC) and chlorhexidine (CHX) showed the greatest fungicidal activity with the lowest minimum fungicidal concentrations (0.38% and 0.78%, respectively). Oral rinses based on zinc chloride and sodium fluoride with Miswak bark extract (MIS) or essential oils (EO) had much lower fungicidal activity (8–16 times lower) compared to CHX and CPC. However, they had a significantly greater impact on the virulence traits of C. albicans. They reduced germ tube production by 86–89% (vs. 42% for CHX and 29% for CPC), completely inhibited phospholipase and hemolysin production, and together with the CPC-based oral rinse, exerted the greatest reductions in biofilm formation across all tested concentrations. This was in contrast to both the controls and CHX, which had a minimal effect on biofilm formation. Conclusion: By inhibiting the virulence factors, the oral rinse can have a crippling effect on C. albicans, weakening this opportunistic pathogen and hindering its potential to cause infection.

Biochemical typing and evaluation of pathogenicity in vulvovaginal isolates of Candida albicans complex

Candida albicans, C. dubliniensis, and C. africana form the Candida albicans complex. To identify the phenotypic and pathogenic characteristics of isolates of the C. albicans complex preserved in a collection. Three hundred presumptive strains of the C. albicans complex were evaluated using CHROMagarTM Candida. Germ tube production was determined by three methods, chlamydospores formation was assessed and colonies were characterized in artisanal agars (Rosmarinus officinalis and Nicotiana tabacum). MALDI-TOF was used as the gold standard identification test. To detect pathogenicity factors, we evaluated the hemolytic activity of each isolate and cocultured with Staphylococcus aureus, coagulase enzyme production, and biofilm formation. Out of the 300 isolates, 43.7% produced germ tube in the heart-brain infusion broth and 47% of the isolates produced chlamydospores. In the artisan media, 6% of the isolates produced brown colonies on rosemary agar and 5% did so on tobacco agar. None of the strains hemolyzed the blood agar alone or cocultured with S. aureus. However, 50% of the isolates hemolyzed the potato dextrose agar supplemented with blood. All strains were coagulase producers, and biofilm production was variable. For germ tube production, the human serum method showed the same positivity as the milk broth method. All isolates were identified as C. albicans by MALDI-TOF. The use of proteomics, molecular tests or a combination of methods is required for species identification.

Activity of the new OSBP inhibitor Y18501 against Pseudoperonospora cubensis and its application for the control of cucumber downy mildew

Y18501 is a new oxysterol-binding protein inhibitor (OSBPI) with a similar structure to oxathiapiprolin. Y18501 showed strong inhibitory activities against Phytophthora spp. and Pseudoperonospora cubensis, with EC50 ranging from 0.0005 to 0.0046 μg/mL. It also had good control efficacy on cucumber downy mildew (CDM) in the green house and in the field, and could effectively inhibit different development stages of P. cubensis, especially for sporangiophore production, sporangial production, mycelium extension, and elongation of germ tube. In addition, Y18501 showed excellent protective and curative activities against P. cubensis. It also had acropetal systemic mobility in the cucumber leaves, and could be taken up and translocated to the upper leaves more effectively from the lower leaves than from the roots. Y18501 had poorer permeability in cucumber leaves compared to oxathiapiprolin. The simultaneous application of Y18501 and chlorothalonil could significantly promote the inhibition of P. cubensis.

Syzygium aromaticum extracts debilitate Candida albicans by radically inhibiting its morphological plasticity and biofilm formation

ABSTRACT The effects of Syzygium aromaticum extracts on the growth, germ tube production, biofilm formation and adhesion of Candida albicans to human buccal epithelial cells (BEC) were investigated. We found larger zones of inhibition of growth of C. albicans with the essential oil (EO) and methanolic extract (ME) than amphotericin B. Similarly, the MIC values for the EO and ME were lower than that of amphotericin B. The EO and ME caused greater reductions in biofilm formation than amphotericin-B. Pre-treatment of C. albicans and BEC with the EO caused greater reductions in adhesion to BEC than amphotericin B.

The influence of temperature and vapour pressure deficit on conidia germination and germ tube production in an Australian Podosphaera xanthii isolate

Powdery mildew of cucurbits, caused by Podosphaera xanthii, is an economic constraint in cucurbit production worldwide. This study examined the influence of temperature and vapour pressure deficit (VPD) on the rate of conidial germination and the formation of germ tubes in an Australian P. xanthii isolate 12 – 48 h after inoculation. Two experiments were prepared by inoculating cucumber, cv. crystal salad, leaf-discs using a spore settling tower. The first experiment incubated inoculated cucumber leaf-discs at eight temperatures between 8 and 35 °C under saturated vapour pressure (SVP), the second compared 18 VPD conditions between 0.038 and 1.797 kPa, in six humidity chambers (33% – 99% relative humidity) and three temperatures (22 °C, 25 °C, 28 °C). Leaf-discs were cleared, stained and microscopically inspected for conidial germination and the number of germ tubes. The optimal temperature for germination was 28ºC at SVP, where more than 50% of conidia had germinated by 12 h, and 85% by 48 h. Fewer germinated conidia were recorded after 12 h at other temperature treatments between 17 °C and 31 °C. The germination percentage and germination rate were significantly lower when vapour pressure was between 0.13 and 2.5 kPa, with germination in response to VPD varying by approximately 10%, indicating difficulty associating conidial germination to VPD above 0.13 kPa. Germ tube production was highest between 25 ºC and 28 ºC at the lowest VPD treatment at near SVP, with more than 50% of the germinated conidia producing at least three germ tubes. Germination and formation of germ tubes significantly reduced when VPD increased. P. xanthii conidia were able to produce a primary germ tube under relatively dry conditions, such as 2.53 kPa, but these results show infection would be less likely and require longer incubation. This study provides the first crucial step in simulating powdery mildew infections on cucurbit plants and may lead to a model capable of providing risk forecasts or fungicide management decision support tools.

The influence of temperature and vapour pressure deficit on conidia germination and germ tube production in an Australian Podosphaera xanthii isolate.

The influence of temperature and vapour pressure deficit on conidia germination and germ tube production in an Australian Podosphaera xanthii isolate.

P466 Isolation of Cryptococcus neoformans and other yeast from pigeon droppings in Khartoum state, Sudan

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PMObjectivesThe aim of this study was to investigate the presence of Cryptococcus neoformans and other yeast species in pigeon droppings in Khartoum state, Sudan.MethodsSample collection A total of 120 samples were collected from pigeon droppings from Khartoum state. Pigeon droppings were collected using sterile wooden spatulas and placed directly in clean plastic bags.Processing of sampleApproximately 2 g of pigeon droppings were added to 10 ml of sterile saline. The samples were allowed to stand for 20 min with frequent vortex.Isolation and Identification of yeast isolatesA loopful of supernatant fluid from prepared samples was taken and streaked onto Sabouraud's dextrose agar media supplemented with 0.05 mg/ml chloramphenicol incubated at 37°C for 1-2 days. All yeast isolates were identified by direct microscopic examination using the lacto-phenol-cotton-blue stain India ink stain and Gram's stain. Further confirmatory tests were conducted using Corn Meal Agar (CMA) with tween 80, germ tube production test using horse serum, and urease test. Confirmation of identification was done using API 20C AUX and API ID 32C AUX (bioMérieux®, Madrid, Spain).Results Cryptococcus neoformans is the most common species isolated from pigeon droppings as shown in Table 1. Different Candida species have been isolated Figure 1.Isolated yeastNumber Cryptococcus neoformans 42 Candida spp34 Cryptococcus albidus 5 Stephanoscus ciferrii 4 Rhodotorula glutinis 4 Rhodotorula mucilaginosa 3 Geotrichum capitatum 2 Zygosaccharomyces spp1ConclusionThe present study concluded that there is a potential role of pigeons as a reservoir for C. neoformans and other zoonotic yeasts in the environment that can affect humans and animals.

The Effect of Juniperus virginiana Essential Oil on Candida albicans Biofilm Formation

Candida albicans is one of the most important natural microbiotas in human. It is responsible for creating various types of candidiasis as opportunistic yeast. Biofilm formation is one of the pathogenic factors of Candida albicans that triggers infection from any surface on which it is formed. In this study, the effect of Juniperus virginiana essential oil (JVEO) on growth, germ tube production and biofilm formation against C. albicans ATCC 10231 was investigated. JVEO effectively inhibited C. albicans biofilm formation with a minimum inhibitory concentration (MBIC50) of <1250μg/ml. Moreover, it suppressed hyphal growth and germ tube and biofilm formation in that strain. Transcriptomic analysis carried out by qRT-PCR revealed that the expression of HWP1, ALS3 adhesion related genes and CPH1, CYR1, UME6, HGC1 and EED1 hypha formation and maintenance related genes were all suppressed by JVEO. Furthermore, in the cAMP-dependent protein kinase pathway, RAS1 was down regulated but EFG1 was not affected. These results suggest that JVEO may be a potential therapeutic treatment and control of Candida biofilm formation.

A comparative study for production of germ tube in Candida albicans of various pulmonary samples, by different methods in a tertiary care hospital of south west Rajasthan

Background: Systemic candidiasis is associated with a high crude mortality rate, even with first line antifungal therapy. C. albicans is the predominant cause of invasive fungal diseases which is a serious public health issue. The main objective was to assess the reliability of different media for germ tube production in Candida albicans isolated from various clinically diagnosed pulmonary samples.Methods: All Candida isolates were identified and speciated by conventional methods such as Gram’s staining, germ tube test, chlamydospore formation on corn meal agar, sugar fermentation test, sugar assimilation test, and growth on Hi-chrome candida agar.Results: Out of 108 clinical isolates of Candida albicans, 5 different methods were used for germ tube production. Pooled human sera showed 93/108 (86.1%) was the most sensitive method wherein YEPD (yeast extract peptone dextrose) broth 91/108 (84.7%) was the reliable and easy method for detection of germ tube, followed by trypticase soy broth 81/108 (81.4%); peptone water 80/108 (74.7%) and 2% sucrose 71/108 (65.7%).Conclusions: YPED broth is found to be a better serum free substrate and subsequently for the presumptive differentiation of C. albicans from non-albicans candida (NAC), without the extensive time required for the preparation and testing of pooled human serum. Furthermore, this medium is commercially available, more stable, effective, and is not bio hazardous.

Silver Nanoparticles Biosynthesized with Spruce Bark Extract-A Molecular Aggregate with Antifungal Activity against Candida Species.

Due to their high content of biomolecules, combined with silver’s well known antimicrobial potential, silver nanoparticles biosynthesized using spruce bark (AgNP SBEs) demonstrate antibacterial and antioxidant activity, making them a versatile option for developing new antimicrobial agents that might be used for medical treatment or as adjuvants for the classical agents. This study aims to analyze if silver nanoparticles (AgNPs) mediated by spruce bark extract (SBE) and silver salts (AgNP SBE Acetate, AgNP SBE Nitrate) presents antifungal activity against five different Candida spp., synergistic activity with fluconazole, and if they interact with some virulence factors of C. albicans. AgNP SBEs presented MICs (minimum inhibitory concentrations) for all the five tested Candida spp. AgNP SBEs inhibited the growth of C. parapsilosis, C. krusei, and C. guilliermondii, exerted synergistic activity with fluconazole for C. parapsilosis and C. guilliermondii, and inhibited biofilm production for C. albicans, C. auris, and C. guilliermondii. MICs of AgNP SBE Acetate significantly inhibited the production of germ tubes of C. albicans. The expression of C. albicans SAP2 gene was down-regulated by the short-time treatment with MICs of AgNP SBE Acetate, while ALS3 and HSP70 genes were up-regulated by the AgNPs MICs. These results emphasize the potential of using the AgNP SBEs as treatments/adjuvants options, not only against the redundant C. albicans but also for the non-albicans Candida species (which are not as frequently involved in human pathologies, but, sometimes, can be more aggressive).

In Vitro Antifungal Activity of Silver Nanoparticles Biosynthesized with Beech Bark Extract.

Biosynthesis is a green method for the synthesis of silver nanoparticles (AgNPs). This study aimed to assess the antifungal activity of two silver nanoparticle solutions, synthesized using beech bark extract (BBE) and acetate and nitrate silver salts (AgNP Acetate BBE and AgNP Nitrate BBE), their influence on biofilm production, their potential synergistic effects with fluconazole, on different Candida spp., and their influence on virulence factors of C. albicans (germ tube production, gene expression for ALS3, SAP2, HSP70). Both the AgNP BBEs presented different minimum inhibitory concentrations for all the studied Candida spp., but biofilm production was inhibited only for C. albicans and C. guilliermondii. The growth rates of all the studied Candida spp. were inhibited in the presence of both AgNP BBEs, except for C. auris. Synergistic activity was observed for C. parapsilosis and C. guilliermondii, for different combinations of fluconazole with both the AgNP BBEs. The germ tube production of C. albicans was slightly inhibited by the AgNP BBEs. Only AgNP Acetate BBE was able to down-regulate the expression of SAP2. Overall, we can conclude that, even if more studies are necessary, AgNPs synthesized with beech bark extract might be an interesting alternative to classic antifungal treatments.

Leaf blast disease in finger millet [Eleusine coracana (L.) Gaertn.] caused by Bipolaris sorokiniana Sacc.: a histopathological study

Finger millet (Eleusine coracana L.) is a staple food in many African and South Asian countries and is ranked fourth among millets produced worldwide. Finger millet crops are affected by a number of diseases, including blast disease, which is the most destructive and widely distributed disease of the world. It is generally caused by Pyricularia grisea (Cooke) Sacc. We observed blast like symptoms in finger millet crops in the field in Doddamaragowdana halli, Mysore District, India. The infected leaves were subjected to analysis to identify the causative agent. Histopathological studies were conducted at different stages of infection (namely 3, 6, 12, 24, 48 till 72 h) and infection process was observed beginning with adhesion of conidia on the leaf surface, production of germ tube, aspersorium formation followed by formation of hyphae and conidia. Based on the morphological characteristics of the colony, conidiophores and conidia as well as by performing Koch’s postulate the organism was identified. Based on our results, the pathogen isolated from the foliar samples of finger millet collected from infected field was identified as Bipolaris sorokiniana Sacc. To our knowledge, this is the first report of blast disease in finger millet caused by Bipolaris sorokiniana Sacc.

Mezoneuron benthamianum inhibits cell adherence, hyphae formation, and phospholipase production in Candida albicans.

The aim of this study was to evaluate the phytochemical constituents, antioxidant, antifungal, and anti-virulence activities of traditionally used Mezoneuron benthamianum leaves. Extracts were prepared using acetone and methanol, and the preliminary phytochemical screening was performed. The antioxidant activity was studied using the DPPH method. Anti-Candida albicans activity was established and the effect on the germ tube and phospholipase production, as well as on the host cell adherence was assessed. The extracts showed the presence of anthraquinones, cardiac glycosides, flavonoids, reducing sugars, saponins, steroids, tannins, and terpenoids. Gallic acid and trans-resveratrol were among the predominant phytochemicals found in M. benthamianum. The crude extracts presented significantly higher antioxidant activity than the ascorbic acid standard. At 0.39mg/mL, acetone extract inhibited the growth of Candida albicans. At lower concentrations (200-50µg/mL), it significantly inhibited the adherence ability (up to 51%), formation of hyphae (up to 65%), and the production of phospholipase. In conclusion, at high concentrations, M. benthamianum kills C. albicans, and at lower concentrations, it can inhibit the virulence properties of this pathogen. This study on crude extract validates the traditional use of this plant. However, further research is required to establish the anti-virulence activity of the two compounds and their therapeutic potential.

Tomato juice as a potential replacement for human serum in germ tube test assay

Candida albicans (C. albicans) is the most common opportunistic fungal pathogen often isolated from clinical samples. Traditionally, the differentiation of C. albicans from other Candida species is performed through the germ tube test using human serum. The aim of this study was to assess the use of tomato juice of “Thilina” variety for the differentiation of C. albicans from other non albicans species. This study was carried out using 66 Candida isolates including five Candida standards. Candidal suspension (100 μl) equals to 0.5 McFarland was mixed with 1 ml of fresh human serum and 1 ml of tomato juice, separately. Test tubes were incubated at 37 oC and the observations were made at 15 minute intervals for two hours. The tomato juice exhibited 97% sensitivity, 100% specificity, 97% positive predictive value, 100% negative predictive value and higher positive correlation (R2 > 0.6) in producing results. There was no statistically significant difference (P = 0.05) in the meantime of initial germ tube production when tomato juice was compared with the routine serum medium. For the first time the study strongly suggests that human serum can be replaced by juice of “Thilina” variety of tomato for the differentiation of C. albicans from non albicans species.

Utility of non-serum liquid media against conventional human serum in germ tube production test

: , a predominant yeast pathogen can be easily distinguished from other non-albicans species in a diagnostic laboratory based on their property to produce germ tubes using human serum as a routine substrate. As usage of human serum is accompanied with risk of transmission of blood-borne viral infections, several other media were employed by many clinical laboratories. The aim of this study was to evaluate the efficacy of four commonly used non-serum liquid media relative to fresh human serum in germ tube (GT) productivity among various Candida isolates. A total of 146 Candida isolates (96 ; 47 ; 3 ) identified by conventional methods were assessed for germ tube production in five types of media namely peptone water, Mueller Hinton broth, Trypticase soy broth, Brain Heart infusion broth and fresh human serum . Results obtained in different media for germ tube production in all Candida isolates were analysed for sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy.All the Candida isolates showed 100% specificity and PPV in all the five-liquid media. Highest performance in germ tube production (96%) in isolates was found in Trypticase soy broth followed by fresh human serum (95%). Trypticase soy broth was shown to have 96% sensitivity and 97% accuracy for germ tube formation comparable to human serum with 95% sensitivity and 96.5% accuracy. Trypticase soy broth can be suggested as a choice medium for GT production in diagnostic mycology.

Identification of Candida spp. isolated from oral mucosa in patients with leukemias and lymphomas in Iran

Oral candidiasis is a serious problem for immunocompromised patients, especially patients with hematological malignancies. After becoming a systemic candidiasis it is difficult to diagnose, control and treat in individuals with hematological malignancies. The aim of this study was to diagnose candidiasis in the oral mucosa of patients with leukemias and lymphomas in a timely manner in order to prevent their progression to systemic candidiasis. In this cross sectional study, 50 clinical samples were collected from the mouth of patients with hematological malignancies undergoing chemotherapy from the oncology units of teaching hospitals in Kerman, Iran. Patients were from Kerman, Sistan-Baluchestan and Hormozgan in south-eastern Iran. Sampling was restricted to patients with diagnosed acute lymphoid leukemia (ALL); acute myeloid leukemia (AML); chronic lymphoid leukemia (CLL); chronic myeloid leukemia (CML); Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). Presumptive species identification of fungi was performed using conventional methods like colony characteristics on CHROMagar Candida medium, germ tube production, and assessing the morphology fungi on corn meal agar. Confirmation of presumptive candida isolates was performed using PCR-RFLP. From a total of 50, 14 patients (28%) had positive oral candidiasis. Candida albicans (57.14%) was the most common species followed by Candida glabrata (14.28%), Candida parapsilosis (14.28%), Candida krusei (7.14%) and Candida kefyr (7.14%). Candida albicans had the highest rate of oral infection in ALL (35.71%) and then NHL (28.57%) patients. The results indicate that oral candidiasis is a prevalent fungal infection in the patients with hematologic malignancies with C. albicans being the main etiological agent. However, other species of Candida cause similar infections in these patients.