Evaluation of the Performance of the Dynamiker Fungus (1-3)-β-D-Glucan and Fungitell Assay for Diagnosis of Candidemia: Need for New Cut-off Development and Test Validation

(1-3)-Beta-D Glucan (BDG) detection has shown to be a highly effective tool to diagnose invasive fungal infections. Therefore, this study aimed to compare clinical characteristics of the Fungitell (FA) and Dynamiker Fungus (1-3)-β-D-Glucan assay (DFA) for the diagnosis of candidemia. Using DFA and FA, the BDG levels of 57 serum samples from case and control groups were determined. The kappa coefficient (κ) and Spearman's rank correlation (rs) were used to examine the consistency of assays on a quantitative and qualitative level, respectively. The sensitivity, specificity, and accuracy were 94.6 %, 65.0 %, and 87.7% for DFA, and 94.6 %, 75.0 %, and 89.4 % for FA, respectively. The performance of the DFA for the diagnosis of candidemia was highly consistent with that of the FA, both quantitatively (rs: 0.9) and qualitatively (kappa = 0.78). Collectively, the DFA assay performed excellently in comparison to the FA for the diagnosis of candidemia.

Chemical Composition and Antifungal and Antibiofilm Effects of Vitex pseudo-negundo Essential Oil against Pathogenic Fungal Strains

Background

Vitex pseudo-negundo is a plant of the Lamiaceae family that grows in different parts of the world and the vicinity of seasonal rivers in Iran.

Methods

The chemical composition of the Vitex pseudo-negundo essential oils was distilled and evaluated using gas chromatography/mass spectrometry. The antifungal activity of the essential oils against the fungal strains was analyzed by broth microdilution methods as suggested by the Clinical and Laboratory Standards Institute. Furthermore, the antibiofilm activity of the Vitex pseudo-negundo essential oils was assessed using the XTT reduction assay.

Results

Based on GC/MS analysis, the major components of the Vitex pseudo-negundo essential oils were α-pinene, α-terpinyl acetate, limonene, and (E)-caryophyllene. The growth of tested yeasts was inhibited at concentrations ranging from 2 to 64 μl/mL. Vitex pseudo-negundo fruit essential oil was the most effective in inhibiting yeast growth. Moreover, the essential oils exhibited antifungal activity against filamentous fungi strains. Additionally, the biofilm formation of Candida albicans was inhibited by the leaf, flower, and fruit of the essential oils.

Conclusion

Considering the significant antifungal activities of these essential oils, they can be considered a potential source for formulating novel agents to control fungal infections.

Iranian National Survey on Tinea Capitis: Antifungal Susceptibility Profile, Epidemiological Characteristics, and Report of Two Strains with a Novel Mutation in SQLE Gene with Homology Modeling

BACKGROUND

The data on the epidemiological and antifungal susceptibility profile of tinea capitis (TC) in Iran has not been updated in recent decades. This report presents the Iranian epidemiological and drug susceptibility data regarding the distribution of dermatophytes species isolated by six national mycology centers for a period of one year (2020-2021).

MATERIAL AND METHODS

A total of 2100 clinical samples from individuals suspeted to TC were subjected to mycological analysis of direct microscopy and culture. For definite species identification, the culture isolates were additionally subjected to PCR-RFLP and PCR-sequencing of the ITS ribosomal DNA (ITS-rDNA) region. Antifungal susceptibility profiles for eight common antifungal drugs were determined by CLSI M38-A3 guidelines. The SQLE gene was partially amplified and sequenced in two terbinafine-resistant and two susceptible T. mentagrophytes isolates to elucidate probable substitutions involved in resistance.

RESULTS

TC (n = 94) was diagnosed in 75 children (79.8%) and 19 adults (20.2%) by direct microscopy and culture. Frequency of TC was significantly more among males (66 males = 70.2% vs 28 females = 29.8%). The prevalent age group affected was 5-9 years (39.36%). Thirty-two (34.04%) T. mentagrophytes, 27 (28.7%) T. tonsurans, 14 (14.9%) M. canis, 13 (13.8%) T. violaceum, 5 (5.32%) T. indotineae, 2 (2.1%) T. benhamiae, and 1 (1.1%) T. schoenleinii were identified as the causative agents. MIC values of isolates showed susceptibility to all antifungal agents, except for fluconazole and griseofulvin with GM MIC of 11.91 μg/ml and 2.01 μg/ml, respectively. Terbinafine exhibited more activity against isolates, with GM MIC 0.084 μg/ml followed by ketoconazole (0.100 μg/ml), econazole (0.107 μg/ml), itraconazole (0.133 μg/ml), butenafine (0.142 μg/ml), and miconazole (0.325 μg/ml). Two resistant T. mentagrophytes isolates harbored missense mutations in SQLE gene, corresponding to amino acid substitution F397L. Remarkably, one unique mutation, C1255T, in the SQLE sequence of two terbinafine-susceptible T. mentagrophytes strains leading to a change of leucine at the 419th position to phenylalanine (L419F) was detected.

CONCLUSIONS

T. mentagrophytes, T. tonsurans, and M. canis remained the main agents of TC in Iran, however less known species such as T. indotinea and T. benhamiae are emerging as new ones. Terbinafine could still be the appropriate choice for the treatment of diverse forms of TC.

Development of a high-resolution melt-based assay to rapidly detect the azole-resistant Candida auris isolates

Background and Purpose

Candida auris is a multidrug-resistant yeast that rapidly spreads, making it the leading Candidate for the next pandemic. One main leading cause of emerging resistant C. auris isolates is nonsynonymous mutations. This study aimed to detect the Y132F mutation, one of the most important azole resistance-associated mutations in the ERG-11 gene of C. auris, by developing a reliable high-resolution melt (HRM)-based method.

Materials and Methods

Five C. auris isolates from Iran, plus three control isolates from other Clades were used in the study. The antifungal susceptibility testing through micro broth dilution was performed to recheck their susceptibility to three azole antifungals, including fluconazole, itraconazole, and voriconazole. Moreover, the polymerase chain reaction (PCR) sequencing of the ERG-11 gene was performed. Following the bioinformatic analysis and HRM-specific primer design, an HRM-based assay was developed and evaluated to detect ERG-11 mutations.

Results

The minimum inhibitory concentrations of fluconazole among Iranian C. auris isolates ranged from 8 to 64 μg/mL. The PCR-sequencing of the ERG-11 gene and bioinformatic analyses revealed the mutation of Y132F, a substitution consequence of A to T on codon 395 in one fluconazole-resistant isolate (IFRC4050). The developed HRM assay successfully differentiated the targeted single nucleotide polymorphism between mutant and wild types (temperature [Tm]: 81.79 ℃ - cycle threshold [CT]: 20.06 for suspected isolate). For both mutant and non-mutant isolates, the mean Tm range was 81.79-82.39 °C and the mean CT value was 20.06-22.93. These results were completely in accordance with the findings of DNA sequencing.

Conclusion

The fast-track HRM-based method successfully detected one of the most common mechanisms of resistance in the ERG-11 gene of C. auris within 3 h. Finally, the development of more panels of HRM assays for the detection of all azole resistance mutations in C. auris ERG-11 is recommended to expand the scope of the field and facilitate the elaboration of rapid and accurate methods of antifungal resistance assessment.

Molecular identification and antifungal susceptibility profiles of etiologic agents of oral candidiasis among HIV-positive patients: A multicenter study

Background and Purpose

Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) is a serious risk factor for oral candidiasis (OC). In this regard, the present study aimed to investigate the frequency of Candida species collected from the oropharyngeal cavity of HIV-positive patients and the sensitivity of these isolates to antifungal drugs.

Materials and Methods

Oral samples were collected from 169 HIV-positive patients. In addition to culture-based methods, a molecular assay via the polymerase chain reaction-restriction fragment length polymorphism method was applied to identify isolates using the MspI restriction enzyme. The disk diffusion method determined the susceptibility of isolated yeasts to common antifungal drugs according to the CLSI M44-A2 protocol.

Results

In total, 81 participants (47.92%) were positive for OC, and Candida albicans was the most prevalent yeast (53.98%). The median age of patients was 36 years old (IQR=10.5; 17-59), and it was found that women are 27% more susceptible to HIV-associated OC (OR=1.268; 95% CI: 0.685-2.348). Patients who received antifungal therapy had a 97.3% reduced chance for OC (OR: 0.027; 95% CI: 0.008-0.091; P-value: 0.000). Antifungal therapy reduced the risk of OC by 97.3% (OR=0.027; 95% CI=0.008-0.091; P=0.000), and antiretroviral therapy decreased the chance of OC 4.42 times (OR=4.423; 95% CI=1.697-11.528; P=0.002). The resistance rates for antifungals, namely fluconazole, ketoconazole, itraconazole, amphotericin B, and nystatin were 15.93%, 8.85%, 7.96%, 5.31%, and 4.42%, respectively.

Conclusion

Although several decades have passed since the emergence of HIV/AIDS, little information is available about fungal colonization and infections in this population. Further investigations are suggested using novel and reference molecular identification methods, such as matrix-assisted laser desorption ionization time-of-flight mass spectrometry and sequencing, respectively. In addition, more reliable methods for antifungal susceptibility testing are recommended.

Phenotypes characterization and ABC genotypes distribution of clinical Candida albicans isolates

BACKGROUND

Candidemia and vaginitis are the most common types of candidiasis mostly caused by Candida albicans species. C. albicans has several genotypes and the potential ability to form different phenotype colonies on specific media. This study aimed to evaluate the genotype distribution of blood and vaginal C. albicans isolates and phenotype characteristics on Spider and yeast peptone dextrose agar medium.

METHODS

A total of 40 clinical Candida albicans isolates comprising vagina (20) and blood (20) were used. ABC typing using CA-INT-R and CA-INT-L primers was performed to span the transposable group I intron of the 25S rDNA gene. For colony phenotypic characteristics, the Spider and YPDA media were used.

RESULTS

Among the blood and vaginal isolates, genotype A (12/60%) and genotype C (10/50%) were the most common types, respectively. The highest phenotype shape frequency of the colonies in blood and vaginal samples was the ring and the lowest was the hat/ring. The dominant color phenotype in blood and vaginal samples was gray. There was a significant relationship between genotype and phenotype forms in the blood sample on YPDA medium (p = 0.02). In the Spider medium, there were no significant differences between genotypes and phenotypes.

CONCLUSION

In this study, genotype A and genotype C were predominant in blood and vaginal samples, respectively. In both groups, YPD agar medium demonstrated the most variety of phenotypes that was related to genotypes A and C. The variety of phenotypes in both groups was the same in genotypes A and C on the Spider medium.

P358 Candida auris survival on common medical supply surfaces under different environmental conditions

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM

 

Background

Candida auris is an emerging multidrug-resistant pathogenic yeast. The increasing frequency of C. auris outbreaks is prompting alarm worldwide. This yeast survives and spreads on contaminated medical supplies, resulting in hospital outbreaks. To learn more about the yeast's spreading behaviors and transmission, we studied its persistence and survival on a variety of medical-related surfaces under diverse environmental conditions.

Methods

A total of 104 CFU/mL solutions of four Candida species, including C. auris, C. albicans, C. parapsilosis, and C. glabrata, were inoculated onto different 2 × 2 cm sheets of cotton textile, polystyrene, paper, aluminum, glass, latex, and dried Sabouraud dextrose agar. Inoculated sheets were incubated at various temperatures and subjected to light and darkness at 1, 2, 7, 14, 30, 45, 60, and 120-day intervals. After culture of the sheets on Sabouraud dextrose agar plates, the viable CFUs of yeasts were counted.

Results

All four species remained alive on all surfaces for at least 1 week under ambient and refrigerator temperatures, darkness, and light exposure. However, only latex and polystyrene surfaces maintained viable C. auris and C.parapsilosis for a maximum of 30 days at ambient temperature and darkness. C. auris survived on dried Sabouraud dextrose agar sheets for ˃4 months.

Conclusions

Candida auris and other pathogenic yeasts can survive on a variety of medical surfaces for extended periods of time. Latex and polystyrene devices are the best medical matrices for yeast persistence. If C. auris has access to organic and nutritional components, its survival could be greatly increased. To prevent C. auris transmission, appropriate disinfection and decontamination methods should be considered.

Evaluation of different DNA extraction methods based on steel-bullet beating for molecular diagnosis of onychomycosis

BACKGROUND

Considering increased trends toward molecular methods for detection/identification of fungi causing onychomycosis, the aim of this study is comparison three DNA extraction methods based on steel-bullet beating to extract DNA from nail.

METHODS

Ex -vivo onychomycosis model was developed using bovine hoof with Candida albicans and Aspergillus flavus. For two models, total DNA was extracted using the three different methods. In method 1, the extraction and purification were performed by steel-bullet beating and phenol chloroform protocol, respectively. In method 2, a freezing step were applied before beating. The purification step in method 3 was carried out using a commercial kit, although DNA extraction was done similarly to method 1 in that approach. To evaluate the efficacy of each method, the extracted genomic DNA was amplified with Polymerase Chain Reaction (PCR) using Internal Transcribed Spacer (ITS) regions. Moreover, 50 nail samples were evaluated for onychomycosis using direct microscopy examination as well as PCR in order to evaluate the diagnostic efficiency of the optimal DNA extraction method.

RESULTS

Regarding the desirable quality of the extracted DNA, cost effectiveness, and simplicity, method 1 could be used to extract DNA effectively. Additionally, the obtained data showed that PCR had a higher detection rate of fungal agents in the nail samples than direct microscopic examination.

CONCLUSIONS

This study demonstrated that the mechanical disruption of the cell wall by steel-bullet beating is a useful and practical method to improve the quantity and quality of fungal DNA thorough the extraction process.

Anisakis spp, DNA detection in paraffin-embedded tissue biopsies recovered from patients with gastritis using real-time PCR in Bushehr, Persian Gulf, Iran

Anisakiasis is a zoonotic fish-born parasitic disease caused by anisakid nematodes. Paraffin-embedded blocks containing biopsy samples taken from patients suffering gastritis with unknown causes were investigated by real-time PCR, in the Bushehr region, Iran; where human anisakiasis has not been reported, so far. A total of 50 paraffin-embedded blocks were randomly selected from 250 archived blocks of the patients with gastritis. A SYBER green-based real-time PCR targeting the ITS1 region was developed for the identification of Anisakis genus. An 86 bp partial fragment of the Anisakis spp. ITS1 gene was amplified successfully. A total of 3 out of 50 samples (6 %) had positive amplification in the samples and their pathology reports showed a significant finding of moderate chronic gastritis with or without ulcers. In conclusion, the developed qPCR could be used for detecting Anisakis spp. larval DNA in human biopsy blocks. This study showed the hidden human cases of anisakiasis in the Bushehr for the first time.

Quantitative analysis of in vitro biofilm formation by clinical isolates of dermatophyte and antibiofilm activity of common antifungal drugs

BACKGROUND

The ability of dermatophytes to develop biofilm, as one of the virulence factors in fungal infections which contribute to antifungal resistance, is an outstanding aspect of dermatophytosis that has been noted recently. Because of the paucity of data about the biofilm formation by dermatophytes and their susceptibility to antifungal drugs, this study evaluated the biofilm formation by clinical isolates of dermatophytes and antibiofilm activity of common antifungals widely used to manage dermatophytosis.

METHODS

The ribosomal DNA internal transcribed spacer (ITS) regions sequencing for species identification of 50 clinical dermatophyte isolates was performed. The ability of isolates to form biofilm and inhibitory activity of itraconazole, terbinafine, and griseofulvin against biofilm formation was assayed by the crystal violet staining method. Optical microscopy and scanning electron microscopy (SEM) were applied for the visualization of the biofilm structures.

RESULTS

Trichophyton (T.) mentagrophytes (n: 14; 28%) and T. rubrum (n: 13;26%) were included in more than half of the dermatophyte isolates. Biofilm formation was observed in 37 out of 50 (74%) isolates that were classified as follows: nonproducers (n: 13; 26%), weak producers (n: 4; 8%), moderate producers (n: 16; 32%), and strong producers (n: 17; 34%) by comparison of the absorbance of biofilms produced by clinical strains with control. The mean IC50 values for terbinafine, griseofulvin, and itraconazole were 2.42, 3.18, and 3.78 μg/ml, respectively.

CONCLUSIONS

The results demonstrated that most of the clinical dermatophyte isolates are capable to form biofilm in vitro with variable strength. Moreover, terbinafine can be suggested as the first-line choice for the treatment of biofilm-formed dermatophytosis.

Candida auris: outbreak fungal pathogen in COVID-19 pandemic: a systematic review and meta-analysis

Background and Objectives

Candida auris (C. auris) is the first fungal pathogen considered a global health threat. Because, C. auris is associated with multidrug resistance and associated diseases such as diabetes, sepsis, lung and kidney disease. This study investigated the prevalence and mortality of C. auris infection during Covid-19 pandemic.

Materials and Methods

Databases were searched for peer-reviewed articles published in the English language up to Jan 18, 2022. Heterogeneity across studies was evaluated using Cochrane's Q test and the I2 index. The pooled point prevalences and their corresponding 95% confidence intervals (CIs) were estimated usingthe random-effects model.

Results

In our meta-analysis, 11 eligible articles were included. The total pooled prevalence estimation of C. auris infection among COVID-19 patients was 13% (95% CI: 8%, 19%). The estimated pooled mortality rate of C. auris infection was 37% (95% CI: 15%, 61%). In terms of specific conditions, the pooled risk of mortality was higher in people with diabetes 65% (95% CI: 0.45%, 83%), in cases with >21 days admission inintensive care unit (ICU) 44% (95% CI: 21%, 0.68%), and after receiving steroids 43% (95% CI: 18%, 69%).

Conclusion

Our study highlights the high prevalence rate of C. auris infection, particularly among people with a history of metabolic disorders.

Global Prevalence and Subgroup Analyses of Coronavirus Disease (COVID-19) Associated Candida auris infections (CACa): A Systematic Review and Meta-Analysis

Background

Increased hospitalisation rates in the Coronavirus disease 19 (COVID‐19) era lead to a new wave of hospital‐acquired infections such as emerging multidrug‐resistant Candida auris. We aimed to evaluate and estimate the global prevalence of coronavirus‐associated C. auris infection (CACa).

Methods

We searched related databases between December 2019 and April 2022 for studies that reported data about CACa. Meta‐analysis was performed using MedCalc software version 20.104 according to the DerSimonian and Laird method applying the random‐effects model. We evaluated heterogeneity using the χ²‐based Q statistic (significant for p‐value < .1) and the I² statistic (>75% indicative of ‘notable’ heterogeneity). Moreover, if possible, an odds ratio (OR) analysis was performed for eligible data.

Results

Our meta‐analysis includes ten eligible studies, including 1942 patients hospitalised with COVID‐19; 129 were C. auris cases. The overall pooled prevalence of CACa was estimated at 5.7%. The mortality rate of CACa was estimated at 67.849%. Hypertension was the most prevalent comorbidity (59.374%), followed by diabetes mellitus (52.898%) and cardiovascular diseases (31.392%). Men with a prevalence rate of 80.012% were 3.27 (OR) times more prone to getting infected by C. auris.

Conclusion

We concluded that the prevalence of C. auris infections decreased during the COVID‐19 pandemic and the prevalence gradient changed from Asia to America. Unfortunately, there are many descriptive studies with duplicate content in the field of epidemiology of C. auris infections which are increasing every day. We suggest further non‐descriptive studies to accurately establish the cause‐and‐effect relationships between C. auris and COVID‐19 infections.

Molecular identification of Malassezia species isolated from neonates hospitalized in Neonatal intensive care units and their mothers

Background and Purpose:

Given the important role of Malassezia spp. in skin diseases and other associated infections in neonates, this study aimed to investigate the presence and frequency of Malassezia spp. in the skin of neonates hospitalized in neonatal intensive care units and their mothers using culture and accurate molecular-based methods.

Materials and Methods:

In total, 205 samples were collected from 130 neonates (>4-day-old) and 75 mothers. Isolation of Malassezia spp. from the skin was performed using Leeming-Notman agar and modified Dixon agar media. To compare the Malassezia microflora on the skin of the neonates and their mothers, a polymerase chain reaction-sequencing method was performed for spp. identification of 92 isolates obtained from neonates and their mothers. Moreover, possible associated risk factors for the colonization of Malassezia spp. on the skin were recorded.

Results:

Cultures from 62.3% of neonates and 77.3% of mothers were positive for Malassezia spp. growth. Malassezia globosa was the most prevalent isolated spp. found in the skin of the study population. It is noteworthy that a rare Malassezia spp., Malassezia arunalokei, was isolated from the skin of one neonate. There was a 76% similarity between the mother-neonate isolate sequences results. The statistical analysis showed that the type of feeding is a significant (P<0.001) associated factor for Malassezia skin colonization.

Conclusion:

The findings support the hypothesis that the colonization of Malassezia in neonates is significantly influenced by that of the mother, and this may be associated with breastfeeding.

Prevalence of superficial-cutaneous fungal infections in Shiraz, Iran: A five-year retrospective study (2015-2019)

Background

Superficial and cutaneous fungal infections are common in tropical areas. The aim of this study was to provide a basic database of superficial and cutaneous mycoses and the most common etiological agents among patients.

Methods

Between 2015 and 2019, a total of 1807 patients suspected of superficial and cutaneous mycosis referring to the mycology laboratory of Shiraz medical school, Fars, Iran were evaluated. Specimens were taken from the patients’ affected area, and clinical samples were examined by direct microscopy and culture. The epidemiological profile of the patients was collected.

Results

A total of 750 patients were confirmed with mycoses. Positive samples totaled 750 cases consisting of the nail (373/49.7%), skin (323/43%), head (47/6.26%), and mucosal membrane (4/0.5%). The yeasts group included 304 Candida spp. (70.3%), 123 Malassezia spp. (28.47%), and 5 Rhodotorula spp. (1.1%). The filamentous fungi were distributed as 34.8% dermatophytes and 7.5% non‐dermatophyte. The clinical types of dermatophytosis were tinea unguium (110/261), tinea capitis (50/261), tinea pedis (48/261), tinea corporis (37/261), and tinea cruris (16/261). Non‐dermatophyte molds included A. flavus 17, A. niger 4, Aspergillus spp. 15, Penicillium. 10, Fusarium 6, Mucor 2, Stemphylium 1, and Alternaria 1.

Conclusion

This study provides useful data for the study trends of superficial and cutaneous fungal infections in a specific area. The mycological data confirmed higher incidence of candidiasis (mainly onychomycosis) and dermatophytosis in patients affected by fungal pathogens, which helped to better understand the epidemiological aspects of these mycoses.

Development a hydrolysis probe-based quantitative PCR assay for the specific detection and quantification of Candida auris

Background and Purpose:

Candida auris is an emerging multidrug-resistant pathogen. The identification of this species with the conventional phenotypic or biochemical mycological methods may lead to misidentification. Molecular-based species-specific identification methods such as quantitative real-time polymerase chain reaction (qPCR) facilitate a more reliable identification of C. auris than mycological methods. Regarding this, the present study aimed to develop a hydrolysis probe-based qPCR assay for the rapid, accurate identification of C. auris.

Materials and Methods:

The internal transcribed spacer 2 regions in the nuclear ribosomal DNA of C. auris and other related yeasts were assayed to find a specific PCR target for C. auris. A 123-base-pair target was selected, and primers and a probe were designed for hydrolysis probe-based real-time PCR with TaqMan chemistry. Ten-fold serial dilutions of C. auris ranging from 106 to 100 CFU/mL were prepared to establish a standard curve to quantify the yeast.

Results:

The qPCR assay was able to identify and quantify C. auris with a detection limit of 1 C. auris CFU per reaction. Specificity was confirmed by the non-amplification of the sequences belonging to other Candida species, yeasts, molds, bacteria, or human DNAs. The standard curve of the assay showed a highly significant linearity between threshold values and dilution rates (R²=0.99; slope=−3.42).

Conclusion:

The applied qPCR assay facilitated the rapid and accurate identification and quantification of emerging opportunistic C. auris. Therefore, considering the promising test validation results, we succeeded to develop a rapid and accurate hydrolysis probe- based qPCR assay for the screening and identification of C. auris.

Optical Coherence Elastography-Based Corneal Strain Imaging During Low-Amplitude Intraocular Pressure Modulation

Purpose: Optical coherence elastography (OCE) is a promising technique for high-resolution strain imaging in ocular tissues. A major strain-inducing factor in the eye is intraocular pressure (IOP), with diurnal physiological fluctuations reaching up to 5 mmHg. We study herein low-amplitude IOP modulation to assess local corneal strain patterns.

Methods:Ex vivo porcine eye globes were adjusted to an initial IOP of 15 mmHg and subsequently 25 mmHg. Corneal strain was induced by two subsequent pressure cycles, in which IOP was first increased and then decreased, each by a total of 5 mmHg. Two-dimensional optical coherence tomography (2D-OCT) B-scans were recorded after each loading step. Axial strain maps were obtained from magnitude and phase changes and supra-pixel displacements from cross-correlation. The strain detection sensitivity was evaluated in an isotropic material.

Results: Deformations arising from a single 1-mmHg step could be resolved. The largest strain amplitudes (5.11·10⁻³) were observed in the posterior stroma at a low initial IOP. Strain amplitude was 1.34 times higher at 15 mmHg than at 25 mmHg (p = 0.003). Upon IOP increase, the anterior cornea was compressed, whereas the posterior cornea showed axial expansion. Both morphological images and strain maps were sensitive to postmortem time. Strains that are larger than 2.44·10⁻⁵ could be reliably measured.

Conclusions: Low-amplitude IOP modulation, similar to diurnal physiological changes, induced measurable deformations in corneal tissue. Axial strain maps permit a localized comparison of the corneal biomechanical response. Small-strain OCE can likely be extended to other domains.

Evaluation of Exoenzyme Activities, Biofilm Formation, and Co-hemolytic Effect in Clinical Isolates of Candida parapsilosis Species Complex

Candida parapsilosis species complex is considered as important emerging pathogens and little is known about their pathogenicity factors and co-hemolytic activity with different bacteria species. The aim of this study was to determine in vitro exoenzyme activities, biofilm formation, and co-hemolytic effect of different bacteria species on clinical C. parapsilosis complex isolates. In total, 67 C. parapsilosis complex isolates consist of C. parapsilosis sensu stricto 63/67 and Candida orthopsilosis 4/67 were used in this study. To determine the hemolytic activity of these species, Sabouraud dextrose sheep blood agar was used. Evaluation of the CAMP-like phenomenon carried out in the presence of Staphylococcus aureus, Staphylococcus saprophyticus, Staphylococcus epidermidis, and Streptococcus agalactiae. Tube test method with ethylenediaminetetraacetic acid-rabbit plasma was used to determine coagulase activity, and biofilm formation was assessed by the tube method in assist of Sabouraud glucose broth (8%) medium. Fisher's exact tests were used for data statistical analysis. Sixty-six of 67 (98.5%) and 3/67 (4.5%) of the species showed hemolysin and coagulase activity, respectively. Fifty-five of 67 (82.1%) of species had ability for biofilm formation, and none of the samples exhibited co-hemolytic effect in the presence of four mentioned bacteria. No significant difference was found between the level of enzyme production and biofilm formation among the isolates.

Utilization of size polymorphism in ITS1 and ITS2 regions for identification of pathogenic yeast species

PURPOSE

Despite the existence of a variety of available yeast-identification strategies, easier and more cost-effective methods are required for routine use in clinical laboratories. The internal transcribed spacer (ITS) regions of fungal rRNA genes exhibit variable sizes depending on the yeast species. In the present study, fragment size polymorphism (FSP) analysis of the ITS1 and ITS2 regions for identification of the clinically most important yeast species was assessed.

METHODOLOGY

The ITS1 and ITS2 regions of 190 strains, including isolates of 31 standard strains and 159 clinical isolates, were separately PCR amplified with two primer sets: ITS1-ITS2 and ITS3-ITS4. PCR products were mixed and the two-band electrophoretic pattern of each sample was analysed according to the size of the ITS regions as predicted from the GenBank database.

RESULTS

Using this method and avoiding expensive tools such as sequencing or capillary electrophoresis, we were able to differentiate nearly all pathogenic yeast species, including Candida albicans, Candida tropicalis, Candida glabrata, Candida parapsilosis, Candida krusei, Candida guilliermondii, Candida kefyr, Candida lusitaniae, Candida rugosa, Cryptococcus neoformans and Saccharomyces cerevisiae. The method showed limited discriminatory power to differentiate species of the Candida parapsilosis complex. Differentiation of Candida albicans and Candida tropicalis needs already identified controls.

CONCLUSION

FSP method benefits from advantages such as lower cost, higher speed and wider range of species than some commercial yeast-identification methods. We consider this method as one of the easiest molecular approaches for identifying a wide range of human pathogenic yeast species, applicable to both diagnostic and epidemiological purposes.

Proteolytic activity and cooperative hemolytic effect of dermatophytes with different species of bacteria

BACKGROUND AND PURPOSE

Globally, dermatophytes are the most common filamentous group of fungi causing cutaneous mycoses. Dermatophytes were shown to secrete a multitude of enzymes that play a role in their pathogenesis. There is limited data on co-hemolytic (CAMP-like) effect of different bacterial species on dermatophyte species. In this study, we sought to the evaluate exoenzyme activity and co-hemolytic effect of four bacteria on clinical dermatophytes isolated from patients in Shiraz, Iran.

MATERIALS AND METHODS

A total of 84 clinical dermatophyte species were isolated from patients suffering dermatophytosis and identified by conventional methods. Hemolytic activity was evaluated with Columbia 5% sheep blood agar. Proteolytic activity was determined by plate clearance assay method, using gelatin 8% agar. CAMP-like factor was evaluated with four bacteria, namely, S. areus, S.saprophyticus, S.pyogenes, and S.agalactiae. Fisher's exact test was run for statistical analysis.

RESULTS

T. mentagrophytes was the most predominant agent (27 [32.1%]) followed by T. verrucosum(20 [23.8%]), T. tonsurans (10 [11.9%]), Microsporum canis (7 [8.3%]), T. rubrum (6 [7.1%]), E. floccosum (6 [7.1%]), M. gypseum (5 [6%]), and T. violaceum (3[3.6%]). The most common clinical area of dermatophytosis was the skin. All the isolates expressed the zone of incomplete alpha hemolysis. All the isolates had CAMP- positive reaction with S. aureus and the other bacteria were CAMP-negative. All the isolates expressed proteolytic activity and no significant differences were noted among diverse genera of dermatophytes and severities of proteolytic activity.

CONCLUSION

This study indicated that hemolysin and proteolytic enzymes potentially play a role in dermatophyte pathogenesis and S. aureus could be considered as a main bacterium for creation of co-hemolytic effect in association with dermatophyte species.

Growing Incidence of Non-Dermatophyte Onychomycosis in Tehran, Iran

BACKGROUND

Non-dermatophyte onychomycosis (NDO) is caused by a wide range of mold fungi other than dermatophytes, and has been reported at various rates in different countries worldwide. Studies on the incidence of NDO in the community are essential for understanding its epidemiology and control, as well as for the appropriate treatment of these infections.

OBJECTIVES

In this study, the incidence of NDO in Tehran, Iran, was compared to the incidence of onychomycoses due to dermatophytes and yeasts.

METHODS

From 2014 through 2015, samples from a total of 1,069 patients with suspected fungal nail diseases, who were referred to three medical mycology laboratories in Tehran, were collected and subjected to direct examination (all samples) and culture (788 samples). Differentiation of the causative agents of onychomycosis was based on microscopic observation of characteristic fungal elements in the nail samples and growth of a significant number of identical colonies on the culture plate.

RESULTS

Based on only direct microscopy, onychomycosis was diagnosed in 424 (39.6%) cases, among which 35.8% were caused by dermatophytes, 32.7% by yeasts, and 29.3% by non-dermatophyte molds (NDMs), while 2.2% were mixed infections. Direct exam was significantly more sensitive than culture for the diagnosis. The most commonly isolated NDMs were Aspergillus spp. (69.3%, n = 52), followed by Fusarium spp. (n = 7). The other isolated species were Paecilomyces spp., Scopulariopsis spp., Acremonium spp., Cladosporium spp., and Chrysosporium spp., with only one case of each.

CONCLUSIONS

An increasing frequency of NDO compared to onychomycosis due to other causative agents has been noticeable over the past few years in Iran. This epidemiological data may be useful in the development of preventive and educational strategies.

Molecular Epidemiological Survey of Cutaneous Leishmaniasis in Two Highly Endemic Metropolises of Iran, Application of FTA Cards for DNA Extraction From Giemsa-Stained Slides

Background:

PCR has been used for confirmation of leishmaniasis in epidemiological studies, but complexity of DNA extraction and PCR approach has confined its routine use in developing countries.

Objectives:

In this study, recent epidemiological situation of cutaneous leishmaniasis (CL) in two hyper-endemic metropolises of Shiraz and Isfahan in Iran was studied using DNA extraction by commercial FTA cards and kinetoplastid DNA (kDNA)-PCR amplification for detection/identification of Leishmania directly from stained skin scraping imprints.

Patients and Methods:

Fifty four and 30 samples were collected from clinically diagnosed CL patients referred to clinical laboratories of leishmaniasis control centers in Isfahan and Shiraz cities, respectively. The samples were examined by direct microscopy and then scrapings of the stained smears were applied to FTA cards and used directly as DNA source in a nested-PCR to amplify kDNA to detect and identify Leishmania species.

Results:

Fifty four of 84 (64.2%) slides obtained from patients had positive results microscopically, while 79/84 (94%) of slides had positive results by FTA card-nested-PCR. PCR and microscopy showed a sensitivity of 96.4% and 64.2% and specificity of 100% and 100%, respectively. Interestingly, Leishmania major as causative agent of zoonotic CL was identified in 100% and 90.7% of CL cases from Isfahan and Shiraz cities, respectively, but L. tropica was detected from only 9.3% of cases from Shiraz city. All cases from central regions of Shiraz were L. tropica and no CL case was found in Isfahan central areas.

Conclusions:

Filter paper-based DNA extraction can facilitate routine use of PCR for diagnosis of CL in research and diagnostic laboratories in Iran and countries with similar conditions. Epidemiologic changes including dominancy of L. major in suburbs of Shiraz and Isfahan metropolises where anthroponotic CL caused by L. tropica had been established, showed necessity of precise studies on CL epidemiology in old urban and newly added districts in the suburbs.

Edge-preserving ultrasonic strain imaging with uniform precision

Ultrasound elastography involves measuring the mechanical properties of tissue, and has many applications in diagnostics and intervention. A common step in different elastography methods is imaging the tissue while it undergoes deformation and estimating the displacement field from the images. A popular next step is to estimate tissue strain, which gives clues into the underlying tissue elasticity modulus. To estimate the strain, one should compute the gradient of the displacement image, which amplifies the noise. The noise is commonly minimized by least square estimation of the gradient from multiple displacement measurements, which reduces the noise by sacrificing image resolution. In this work, we adaptively adjust the level and orientation of the smoothing using two different mechanisms. First, the precision of the displacement field decreases significantly in the regions with high signal decorrelation, which requires increasing the smoothness. Second, smoothing the strain field at the boundaries between different tissue types blurs the edges, which can render small targets invisible. To minimize blurring and noise, we perform anisotropic smoothing parallel to the direction of edges. The first mechanism ensures that textures/variations in the strain image reflect underlying tissue properties and are not caused by errors in the displacement estimation. The second mechanism keeps the edges between different tissue structures sharp while minimizing the noise. We validate the proposed method using phantom and in-vivo clinical data.

Comparison of Nested Polymerase Chain Reaction and Real-Time Polymerase Chain Reaction with Parasitological Methods for Detection of Strongyloides stercoralis in Human Fecal Samples

This study was performed to evaluate nested polymerase chain reaction (PCR) and real-time PCR methods for detection of Strongyloides stercoralis in fecal samples compared with parasitological methods. A total of 466 stool samples were examined by conventional parasitological methods (formalin ether concentration [FEC] and agar plate culture [APC]). DNA was extracted using an in-house method, and mitochondrial cytochrome c oxidase subunit 1 and 18S ribosomal genes were amplified by nested PCR and real-time PCR, respectively. Among 466 samples, 12.7% and 18.2% were found infected with S. stercoralis by FEC and APC, respectively. DNA of S. stercoralis was detected in 18.9% and 25.1% of samples by real-time PCR and nested PCR, respectively. Considering parasitological methods as the diagnostic gold standard, the sensitivity and specificity of nested PCR were 100% and 91.6%, respectively, and that of real-time PCR were 84.7% and 95.8%, respectively. However, considering sequence analyzes of the selected nested PCR products, the specificity of nested PCR is increased. In general, molecular methods were superior to parasitological methods. They were more sensitive and more reliable in detection of S. stercoralis in comparison with parasitological methods. Between the two molecular methods, the sensitivity of nested PCR was higher than real-time PCR.

Molecular identification of uncommon clinical yeast species in Iran

Background and Purpose:

By using advanced detection/identification methods, the list of emerging uncommon opportunistic yeast infections is rapidly expanding worldwide. Our aim in the present study was sequence-based species delineation of previously unidentified yeasts obtained from a clinically yeast collection.

Materials and Methods:

A total of twenty three out of the 855 (5.7%) yeast isolates which formerly remained unidentified by PCR-RFLP method, were subjected to sequence analysis of the entire internal transcribed spacers (ITS) regions of rDNA. The precise species recognition was performed by the comparison of the sequences with the reliable GenBank database.

Results:

Sequencing analysis of the ITS region of the strains revealed several uncommon yeasts that were not reported previously in Iran. The species include Hanseniaspora uvarum, Saccharomyces cerevisiae, Sporidiobolus salmonicolor, Pichia fabianii, Pichia fermentans, Candida famata, Candida inconspicua, Candida maqnoliae, Candida guilliermondii, Candida kefyr, Candida rugosa, Candida lusitaniae, Candida orthopsilosis, and Candida viswanathii.

Conclusion:

We identified several rare clinical isolates selected from a big collection at the species level by ITS-sequencing. As the list of yeast species as opportunistic human fungal infections is increasing dramatically, and many isolates remain unidentified using conventional methods, more sensitive and specific advanced approaches help us to clarify the aspects of microbial epidemiology of the yeast infections.

Detection of Aspergillus flavus and A. fumigatus in Bronchoalveolar Lavage Specimens of Hematopoietic Stem Cell Transplants and Hematological Malignancies Patients by Real-Time Polymerase Chain Reaction, Nested PCR and Mycological Assays

BACKGROUND

Pulmonary aspergillosis (PA) is one of the most serious complications in immunocompromised patients, in particular among hematopoietic stem cell transplants (HSCT) and patients with hematological malignancies.

OBJECTIVES

The current study aimed to evaluate the incidence of PA and utility of molecular methods in HSCT and patients with hematological malignancies, four methods including direct examination, culture, nested polymerase chain reaction (PCR) and real-time PCR were performed on bronchoalveolar lavage (BAL) specimens in Tehran, Iran.

PATIENTS AND METHODS

During 16 months, 46 BAL specimens were obtained from individuals with allogeneic HSCT (n = 18) and patients with hematological malignancies (n = 28). Direct wet mounts with 20% potassium hydroxide (KOH) and culture on mycological media were performed. The molecular detection of Aspergillus fumigatus and A. flavus was done by amplifying the conserved sequences of internal transcribed spacer 1 (ITS1) ribosomal DNA by nested-PCR and the β-tubulin gene by TaqMan real-time PCR.

RESULTS

Seven (15.2%) out of 46 specimens were positive in direct examination and showed branched septate hyphae; 11 (23.9%) had positive culture including eight (72.7%) A. flavus and three (27.3%) A. fumigatus; 22 (47.8%) had positive nested-PCR and eight (17.4%) had positive real-time PCR. The incidence of invasive pulmonary aspergillosis (IPA) in these patients included proven IPA in 1 (2.2%), probable IPA in 10 (21.7%), possible IPA in 19 (41.3%) and not IPA in 16 cases (34.8%).

CONCLUSIONS

The incidence of IPA in allogeneic HSCT and patients with hematological malignancies was relatively high and A. flavus was the most common cause of PA. As molecular methods had higher sensitivity, it may be useful as screening methods in HSCT and patients with hematological malignancies, or to determine when empirical antifungal therapy can be withheld.

Vitamin D receptor gene polymorphisms in Iranian Azary patients with Behçet's disease

OBJECTIVES

The aim of our study was to investigate the association of four polymorphisms of the VDR gene (FokI, BsmI, TaqI, and ApaI) with their susceptibility to Behçet's disease (BD) and their clinical manifestations with respect to the Iranian Azari population.

METHOD

In this cross-sectional study we considered the BsmI, FokI, ApaI, and TaqI polymorphisms in 50 Iranian Azary patients with BD and 50 healthy controls, with the use of polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP).

RESULTS

A significant difference was found for the FokI polymorphism between the case and control groups. The f allele frequency of 26% was present in BD patients, compared to only 13% in the control group. In addition, the f/f genotype was significantly associated with BD. We found no significant differences between the BD and control groups regarding the distribution of ApaI, BsmI, and TaqI genotype frequencies. We found no association between VDR polymorphisms and the clinical manifestations of BD.

CONCLUSIONS

The VDR f allele and f/f genotype are associated with BD in the Iranian Azari population.

β-D-Glucan Assay in Diagnosis and Monitoring the Systemic Candidiasis in a Rat Model

BACKGROUND

Determination of β-D-Glucan (BDG) in the serum aids to diagnose the invasive fungal infections. The current study evaluated the diagnostic potential value of BDG assay in monitoring the disease in experimental systemic candidiasis in a rat model. The results can provide a useful preliminary data to improve this approach in developing countries.

OBJECTIVES

The present study aimed to evaluate β-D-Glucan assay in diagnosis and monitoring the systemic candidiasis in a rat model.

MATERIALS AND METHODS

Twenty one rats were infected with 10(6) Candida albicans blastospore per rat. Twelve rats were considered as the negative controls (six immunocompromised rats without infection and six intact rats). During a week, every 24 hours the BDG sera level was determined by both Fungitell and Wako kits. To confirm the systemic infection in each rat, the suspensions of their internal organs were cultivated on agar plates and the number of colony forming units (CFU) of C. albicans was counted.

RESULTS

All the infected rats were positive with BDG tests. An increasing level of BDG was observed during early days after injection. The cutoff value for discrimination of BDG positive sera was obtained from the negative sera by the Fungitell kit. The sensitivity, specificity, positive and negative predictive values assessed for the Fungitell kit were 95%, 66.6%, 90.47% and 80%, respectively. These criteria for those of Wako were 90%, 83.3%, 94.7% and 71.4%, respectively.

CONCLUSIONS

While BDG assay seems to be a sensitive and specific adjunctive tool to diagnose and monitor the experimental systemic candidiasis, it seems that measuring the positive cutoff value in different laboratory conditions is necessary for favorable establishment of these tests.

Incidence of pulmonary aspergillosis and correlation of conventional diagnostic methods with nested PCR and real-time PCR assay using BAL fluid in intensive care unit patients

BACKGROUND

Although the incidence of invasive aspergillosis in the intensive care unit (ICU) is scarce, it has emerged as major problems in critically ill patients. In this study, the incidence of pulmonary aspergillosis (PA) in ICU patients has evaluated and direct microscopy and culture has compared with nested polymerase chain reaction (PCR) and real-time PCR for detection of Aspergillus fumigatus and A. flavus in bronchoalveolar lavage (BAL) samples of the patients.

METHODS

Thirty BAL samples obtained from ICU patients during a 16-month period were subjected to direct examinations on 20% potassium hydroxide (KOH) and culture on two culture media. Nested PCR targeting internal transcribed spacer ribosomal DNA and TaqMan real-time PCR assay targeting β-tubulin gene were used for the detection of A. fumigatus and A. flavus.

RESULTS

Of 30 patients, 60% were men and 40% were women. The diagnosis of invasive PA was probable in 1 (3%), possible in 11 (37%), and not IPA in 18 (60%). Nine samples were positive in nested PCR including seven samples by A. flavus and two by A. fumigatus specific primers. The lowest amount of DNA that TaqMan real-time PCR could detect was ≥40 copy numbers. Only one of the samples had a positive result of A. flavus real-time PCR with Ct value of 37.5.

CONCLUSIONS

Although a significant number of specimens were positive in nested PCR, results of this study showed that establishment of a correlation between the conventional methods with nested PCR and real-time PCR needs more data confirmed by a prospective study with a larger sample group.

Indications for brain computed tomography scan after minor head injury

Aims:

Minor head injury (MHI) is a common injury seen in Emergency Departments (ED). Computed tomography (CT) scan of the brain is a good method of investigation to diagnose intracranial lesions, but there is a disagreement about indications in MHI patients. We surveyed the post-traumatic symptoms, signs or past historical matters that can be used for the indication of brain CT scan.

Materials and Methods:

All patients with MHI who were older than 2 years, had a Glasgow Coma Scale (GCS) score ≥13 and were referred to the ED, underwent brain CT scan. Data on age, headache, vomiting, loss of consciousness (LOC) or amnesia, post-traumatic seizure, physical evidence of trauma above the clavicles, alcohol intoxication, and anticoagulant usage were collected. The main outcome measure was the presence of lesions related to the trauma in brain CT scan. For categorical variables, Chi-square test was used.

Results:

Six hundred and forty-two patients were examined by brain CT scan after MHI, and 388 patients (60.4%) did not have any risk indicator. Twenty patients (3.1%) had abnormal brain CT scans. The logistic regression model showed that headache (P=0.006), LOC or amnesia (P=0.024) and alcohol (P=0.036) were associated with abnormal brain CT.

Conclusions:

We suggested that abnormal brain CT scan related to the trauma after MHI can be predicted by the presence of one or more of the following risk indicators: Headache, vomiting, LOC or amnesia, and alcohol intoxication. Thus, if any patient has these indicators following MHI, he must be considered as a high-risk MHI.