Species identification and in vitro antifungal susceptibility testing of Aspergillus section Nigri strains isolated from otomycosis patients

Pathogenic Aspergillus Strains Identification and Antifungal Susceptibility Analysis of 452 Cases with Otomycosis in Jingzhou, China

OBJECTIVE

To study the distribution of pathogenic Aspergillus strains of otomycosis in central China and the identification of their antifungal sensitivity.

METHODS

We collected external ear canal secretions clinically diagnosed as otomycosis from April 2020 to January 2023 from the Department of Otolaryngology-Head and Neck Surgery in central China. The pathogenic Aspergillus strains were identified through morphological examination and sequencing. The antifungal sensitivity was performed using the broth microdilution method described in the Clinical Laboratory Standard Institute document M38-A3.

RESULTS

In the 452 clinical strains isolated from the external ear canal, 284 were identified as Aspergillus terreus (62.83%), 92 as Aspergillus flavus (20.35%), 55 as Aspergillus niger (12.17%). In antifungal susceptibility tests the MIC of Aspergillus strains to bifonazole and clotrimazole was high,all the MIC90 is > 16 ug/mL. However, most Aspergillus isolates show moderate greatly against terbinafine, itraconazole and voriconazole.

CONCLUSION

A. terreus is the most common pathogenic Aspergillus strain in otomycosis in central China. The selected topical antifungal drugs were bifonazole and clotrimazole; the drug resistance rate was approximately 30%. If the infection is persistent and requires systemic treatment, terbinafine and itraconazole can be used. The resistance of Aspergillus in otomycosis to voriconazole should be screened to avoid the systemic spread of infection in immunocompromised people and poor compliance with treatment. However, the pan-azole-resistant strain of Aspergillus should be monitored, particularly in high-risk patients with otomycosis.

Screening Candida auris through a multiplex stepwise PCR algorithm directly from clinical samples of patients suspected of otomycosis in south of Iran; Detection of five cases

BACKGROUND

Otomycosis is an infection of the external auditory canal caused by molds and yeasts with descending frequency. Laboratory diagnosis is usually confirmed by microscopy and culture. However, they are not specific enough to reliably differentiate the causative agents, especially for rare pathogens such as Candida auris. The purpose of the current study was to the molecular screening of C. auris species from direct clinical samples of patients with suspected otomycosis in Southern of Iran.

MATERIALS AND METHODS

A total of 221 ear aspirates collected from 221 patients with suspected otomycosis over a four-year period. All the ear aspirations were examined with pan-fungal primers, then those with a positive result was included in two separate reaction mixtures simultaneously to identify the most clinically relevant Aspergillus and Candida species. The validity of positive samples for C. auris was assessed by sequencing.

RESULTS

Of the 189 pan-fungal positive PCRs, 78 and 39 specimens contained Aspergillus spp. and Candida spp., respectively. Furthermore, 65 specimens showed simultaneous positive bands in both Candida and Aspergillus species-specific multiplex PCR including five samples/patients with positive result for C. auris (5/189; 2.6%). Four out of five cases with C. auris species-specific PCR were reconfirmed by sequencing, while none were positive for C. auris in culture.

CONCLUSION

Unfortunately, due to high treatment failure rates of antifungal classes against C. auris species, rapid and accurate identification of patients colonised with C. auris is critical to overcome the challenge of preventing transmission. This PCR assay can be successfully applied for rapid and accurate detection of C. auris directly in patient samples and is able to differentiate C. auris from closely related Candida species.

Identification of Microbial Community in Otomycosis by Metagenomic Next Generation Sequencing (mNGS): Potential Implication of Treatment with Terbinafine

The present study was designed to identify the microbial community as well as to analyze its diversity by means of metagenomic Next Generation Sequencing (mNGS) in 17 patients with otomycosis treated with terbinafine in the Department of Otolaryngology of Shandong Provincial Hospital from June 2021 to June 2022, so as to evaluate the relationship between microbial community and terbinafine resistance. Those 17 patients were divided into two groups, i.e., Terbinafine Effective Group (TEG, n = 14 cases) and Terbinafine Resistance Group (TRG, n = 3 cases) according to the therapy effect, whose microbial community of secretion of external auditory canal was identified using mNGS. We found that the sequence of bacteria was significantly more than that of fungi and, whereas, the difference between the two groups of bacteria was not significant. There were significant differences in fungal community between the two groups. Aspergillus was the main pathogenic fungus of TEG patients while Malassezia was a dominant fungus in TRG patients. In conclusion, the results from this work indicate that Aspergillus terreusis is the main pathogenic fungus in this cohort of otomycosis patients and MNGS sequencing can offer comprehensive information about the microbial community of otomycosis. The fungus community dominated by Malassezia is more likely to be resistant to terbinafine, which provides certain guidance for clinical treatment of otomycosis with terbinafine.

Molecular strategy for the direct detection and identification of the most common fungal community in cerumen specimens by multiplex PCR

Introduction. Otomycosis is a superficial fungal infection that is responsible for approximately 9-27 % of otitis externa. However, fungal communities in otomycosis are varied, but Aspergillus spp. and Candida spp. are the most common causes of this infection.Hypothesis Statement. The multiplex PCR assay is postulated to be able to directly detect more than one fungal genus in cerumen specimens.Aim. This study aimed to develop and evaluate the role of the multiplex PCR assay in detecting the most common genus of fungi that cause otomycosis directly from the cerumen specimens.Methodology. To detect Candida and Aspergillus/Penicillium genera, three pairs of primers, including pan-fungal, pan-Candida, and pan-Aspergillus/Penicillium, were used in a multiplex PCR. In order to evaluate the performance and reproducibility of the multiplex PCR. the cerumen of 140 patients suspected of otomycosis were investigated.Results. Pan-Candida and pan-Aspergillus/Penicillium primers were designed to amplify the ITS1-5.8S-ITS2 region and the β-tubulin gene, respectively. In the multiplex PCR assay, 64 (47.40 %) and 118 (87.40 %) specimens were positive with pan-Candida and pan-Aspergillus/Penicillium primers, respectively. Double amplicon bands of Candida and Aspergillus were obtained in 51 (37.77 %) specimens. In the culture method, yeast (n=18, 13.33 %) and mould (n=117, 86.66 %) were isolated from 135 cerumen specimens. The sensitivity, specificity, and positive and negative predictive values of the multiplex PCR assays using culture method results as the gold standard were determined to be 94, 33, 97, and 22 %, respectively.Conclusion. In our study, multiplex PCR assays enabled simultaneous detection of two common genera of the causative agent of otomycosis in a cerumen specimen. Regarding the high sensitivity of the first step of the multiplex PCR assay, this assay may be used for the direct detection of Candida and Aspergillus genera in other clinical specimens.

Efficient and accurate diagnosis of otomycosis using an ensemble deep-learning model

Otomycosis accounts for over 15% of cases of external otitis worldwide. It is common in humid regions and Chinese cultures with ear-cleaning custom. Aspergillus and Candida are the major pathogens causing long-term infection. Early endoscopic and microbiological examinations, performed by otologists and microbiologists, respectively, are important for the appropriate medical treatment of otomycosis. The deep-learning model is a novel automatic diagnostic program that provides quick and accurate diagnoses using a large database of images acquired in clinical settings. The aim of the present study was to introduce a machine-learning model to accurately and quickly diagnose otomycosis caused by Aspergillus and Candida. We propose a computer-aided decision-making system based on a deep-learning model comprising two subsystems: Java web application and image classification. The web application subsystem provides a user-friendly webpage to collect consulted images and display the calculation results. The image classification subsystem mainly trained neural network models for end-to-end data inference. The end user uploads a few images obtained with the ear endoscope, and the system returns the classification results to the user in the form of category probability values. To accurately diagnose otomycosis, we used otoendoscopic images and fungal culture secretion. Fungal fluorescence, culture, and DNA sequencing were performed to confirm the pathogens Aspergillus or Candida spp. In addition, impacted cerumen, external otitis, and normal external auditory canal endoscopic images were retained for reference. We merged these four types of images into an otoendoscopic image gallery. To achieve better accuracy and generalization abilities after model-training, we selected 2,182 of approximately 4,000 ear endoscopic images as training samples and 475 as validation samples. After selecting the deep neural network models, we tested the ResNet, SENet, and EfficientNet neural network models with different numbers of layers. Considering the accuracy and operation speed, we finally chose the EfficientNetB6 model, and the probability values of the four categories of otomycosis, impacted cerumen, external otitis, and normal cases were outputted. After multiple model training iterations, the average accuracy of the overall validation sample reached 92.42%. The results suggest that the system could be used as a reference for general practitioners to obtain more accurate diagnoses of otomycosis.

Otomycosis in the South of Iran with a High Prevalence of Tympanic Membrane Perforation: A Hospital-Based Study

INTRODUCTION

Otomycosis is a superficial infection of the external ear caused by fungal pathogens. The genera Aspergillus and Candida are considered the main fungal causative agents, with the predominance of Aspergillus section Nigri. The present study aimed to evaluate the clinical symptoms of patients with otomycosis and predisposing factors and to identify fungal etiological agents using molecular approaches. We also present an overview of published papers on tympanic membrane perforation (TMP) secondary to otomycosis.

MATERIALS AND METHODS

An otorhinolaryngologist collected specimens from external ear canals of patients with suspected otomycosis based on the patient's history and clinical examinations. The specimens were collected using sterile swabs. Fungal isolates were confirmed in clinical specimens by direct microscopy and culture methods. Fungal isolates were identified based on molecular approaches.

RESULTS

In total, specimens from 211 patients with suspected otomycosis were examined. The presence of fungi was confirmed in about 51% of patients based on fungal elements in direct microscopy and culture-positive fungi. Aspergillus tubingensis was the most commonly isolated species (52.77%), followed by Aspergillus niger (25.92%). Otomycosis due to infection with Candida species was observed in 16% of cases. Of note, in 36.11% of cases, otomycosis was associated with TMP.

CONCLUSION

A mycological examination is indispensable for a correct diagnosis in patients with otitis extern. TMP should be considered in patients with otomycosis, as it appears to be relatively common in this population.

Mycetoma due to Aspergillus flavus in a diabetic patient: Case report and literature review

Diabetes mellitus patients are prone to cutaneous and subcutaneous fungal infections due to pathogenic fungi, including dermatophytes, Mucorales, Candida, Aspergillus, and Fusarium species. Here, we report a case of A. flavus mycetoma confirmed by isolation and molecular identification. The case was a 38-year-old male farmer with a seven-year history of type 2 diabetes mellitus, living in Khuzestan, southwest of Iran. The patient presented with a right foot swelling associated with a nodule and multiple discharging sinuses following trauma sustained on the foot while working barefoot on the rice farm, a year ago. The nodule appeared at the site of the trauma two months after the injury. The initial diagnosis was based on direct microscopic examination of lesions scraping using 20% potassium hydroxide and radiology. Molecular analysis confirmed the isolates to be A. flavus. In vitro susceptibility of the isolate to voriconazole, posaconazole, caspofungin, itraconazole, and amphotericin B was determined. Treatment with voriconazole (200 mg twice daily) stopped the purulent discharge, reduced the swelling, and improved the clinical condition within two months. The study emphasizes the importance of wearing footwear to prevent skin trauma as the main risk factor of patient involvement.

Black aspergilli as causes of otomycosis in the era of molecular diagnostics, a mini-review

Otomycosis refers to the fungal infection of the external auditory canal, and less commonly the middle ear. A wide range of fungi can cause this disease, however, the most common etiologies are species of Aspergillus and Candida. Until recent years, Aspergillus niger was thought to be the prevailing species of the genus Aspergillus that causes otomycosis. Using molecular methods, now, it is known that Aspergillus section Nigri comprises several morphologically similar species and all black Aspergillus isolates are not necessarily equivalent to Aspergillus niger. In this review, we focus on the species within the Aspergillus section Nigri and their role as the causative agents of otomycosis.

First molecular report of causative agent of otomycosis due to Aspergillus luchuensis

Otomycosis is a fungal infection of the external auditory canal caused mainly by the genus Aspergillus. Aspergillus luchuensis, an industrially important fungus, is a member of Aspergillus section Nigri. In this report, we present a case of otomycosis due to Aspergillus luchuensis in a 43-year-old female patient. We performed a partial PCR-sequencing of β-tubulin and calmodulin genes to identify the isolate to the species level. Further, we determined the in vitro susceptibility of the isolate to nystatin, clotrimazole and itraconazole according to the Clinical & Laboratory Standards Institute (CLSI) M38-A2 protocol. Accordingly, the minimum inhibitory concentrations of clotrimazole, nystatin and itraconazole were 0.25μg/mL, 0.5μg/mL and 1μg/mL, respectively. This is the first report of clinically relevant isolation of Aspergillus luchuensis identified by a molecular technique as a causative agent of otomycosis.

In Vitro Antifungal Activity of Green Synthesized Silver Nanoparticles in Comparison to Conventional Antifungal Drugs Against Trichophyton Interdigitale, Trichophyton Rubrum and Epidermophyton Floccosum

BACKGROUND

Dermatophytosis is a globally distributed fungal infection. Treatment failure and relapse is common in this disease. Silver nanoparticles are known for their promising antimicrobial activity. The aim of this study was to determine the antifungal activity of these nanoparticles against common dermatophyte species.

METHODS

A set of 30 molecularly identified dermatophytes including Trichophyton interdigitale (n=10), Trichophyton rubrum (n=10), and Epidermophyton floccosum (n=10) were used in this study. Green synthesized silver nanoparticles using chicory (Cichorium intybus) were tested for their antifungal activity in comparison to fluconazole, itraconazole and terbinafine. Interspecies differences in minimum inhibitory concentrations of antifungal drugs and silver nanoparticles were tested using Kruskal-Wallis test in SPSS software version 21.

RESULTS

The highest minimum inhibitory concentrations (MICs) among antifungal drugs were observed for fluconazole [range: 4-64 μg/mL, geometric mean (GM) =17.959 μg/mL], followed by itraconazole (range: 0.008-0.5, GM= 0.066) and terbinafine (range: 0.004-0.25 μg/mL, GM=0.027 μg/mL). Silver nanoparticles showed potent antifungal activity against all dermatophyte isolates with MICs (range: 0.25-32 μg/mL, GM=4.812 μg/mL) higher than those of itraconazole and terbinafine, but lower than fluconazole. MIC values of silver nanoparticles demonstrated significant differences between species (P=0.044), with E. floccosum having the highest MICs (GM=9.849 μg/mL) compared to T. interdigitale (GM=3.732 μg/mL) and T. rubrum (GM=3.031 μg/mL).

CONCLUSION

Silver nanoparticles demonstrated promising anti-dermatophyte activity against the studied dermatophytes. Due to their wide-spectrum activity against other fungal and bacterial pathogens, they could be a potential choice, at least in the case of cutaneous and superficial infections.

Species identification and antifungal susceptibility testing of Aspergillus strains isolated from patients with otomycosis in northern China

BACKGROUND/PURPOSE

There are limited studies on species distribution and susceptibility profiles of Aspergillus strains isolated from patients with otomycosis in China.

METHODS

A total of 69 confirmed Aspergillus species isolates were obtained from ear swabs of patients diagnosed with otomycosis from 2017 to 2018 in northern China. Identification of these Aspergillus isolates at the species level was performed using conventional morphological methods and MALDI-TOF MS in combination with molecular sequencing, and in vitro susceptibility to nine antifungal agents was evaluated using the Sensititre YeastOne system.

RESULTS

The Aspergillus section Nigri had the greatest distribution of Aspergillus isolates. A. welwitschiae (n = 25) was the most predominant isolate in section Nigri, followed by A. tubingensis (n = 12) and A. niger (n = 11). Other Aspergillus species were also isolated, including A. terreus (n = 11), A. flavus/A. oryzae (n = 8), and A. fumigatus (n = 2). Amphotericin B, posaconazole, and echinocandins were highly in vitro active against all the isolates tested. 2.9% (2/69) of the isolates were resistant to azoles in our study, including one A. niger isolate with a high MIC value for itraconazole (ITR) (16 mg/L) and one A. tubingensis isolate cross-resistant to both voriconazole (VOR) (MIC >8 mg/L) and ITR (MIC >16 mg/L). One A. welwitschiae and one A. niger isolate both had increased MIC values of 4 mg/L against VOR.

CONCLUSIONS

A. welwitschiae was the most prevalent Aspergillus species isolated from patients with otomycosis. Our findings also indicated that the azole-resistant Aspergillus section Nigri should be utilized to guide clinical medication for Otomycosis.

Direct Detection and Identification of the Most Common Bacteria and Fungi Causing Otitis Externa by a Stepwise Multiplex PCR

Background

Considering the importance of differential diagnosis of infectious otitis externa (OE), a stepwise PCR-based assay using universal and genus- or species-specific primers for the detection/identification of the most prevalent bacterial and fungal OE was developed and evaluated on the ear aspiration specimens of clinically suspected patients.

Methods and Materials

A total of 120 ear aspiration specimens with otomycosis suspicion were subjected to manual DNA extraction using phenol–chloroform extraction after tissue digestion with a lysis buffer. The multiplex PCR was initially performed using pan-fungal and bacterial homemade primers. Pseudomonas and Staphylococcus specific primers were simultaneously used in one reaction mixture to identify the bacterial genera. Furthermore, for the identification of fungal agents, Candida species-specific multiplex primers targeting the most clinically important Candida species causing OE (i.e., C. albicans, C. parapsilosis, and C. auris), as well as Aspergillus related multiplex PCR identifying the most prevalent Aspergillus species were used in two separate reaction mixtures. All the results of multiplex PCR were interpreted based on the amplicon size.

Results

The overall multiplex PCR-based detection rate of bacterial (n = 88; 73.3%) and fungal (n = 97; 81%) OE was documented to be 100% along with and complete consistency with the results of direct examination and Giemsa staining. Double amplicon bands of bacterial and fungal pathogens were evidenced in 76 specimens (63.3%). Moreover, the positivity rate of pan-fungal PCR was higher than that of the culture result. Out of 88 pan-bacterial positive PCR specimens, 66 and 47 ones were positive for Staphylococcus and Pseudomonas, respectively. In addition, 30 samples exhibited mixed infection of both, and five specimens remained negative. Out of 97 pan-fungal positive PCR specimens, 67 and 51 ones contained Candida and Aspergillus species, respectively. It should be noted that dual amplicon bands of Candida and Aspergillus-related multiplex PCR were yielded in 30 specimens.

Conclusion

The stepwise multiplex PCR assay proved to be more sensitive, more rapid, as well as less cumbersome in detection and identification of fungal and bacterial OE, compared to culture.

Molecular Identification and Antifungal Susceptibility of Yeasts and Molds Isolated from Patients with Otomycosis

Fungal otitis externa, an infection of the external auditory canal caused by molds and yeasts, accounts for approximately 10-20% of ear canal infections accompanying high recurrence. The purpose of the current study was to assess the pattern of etiological agents of otomycosis and resistance profile as well as the rate of tympanic membrane perforation. A total of 1040 patients with symptoms of fungal otitis externa, in a period of two years, were investigated. The mycological tests revealed the presence of different fungi in 237 ears (22.8%). Fungal otitis was more related to filamentous fungi of the species Aspergillus flavus (54.43%), A. tubingensis (10.97%), and A. niger (8.86%), followed by yeasts, Candida orthopsilosis (7.59%), C. albicans (6.75%), and C. parapsilosis (5.06%). Tympanic membrane perforation rate was found to be 6.75% and was more common with otomycosis caused by A. flavus, A. tubingensis and C. albicans. In antifungal susceptibility tests, all tested drugs showed generally good activity against most isolates of molds and yeasts, while tolnaftate, clotrimazole, nystatin, and terbinafine had lowest effects. We found that among Aspergillus isolates, one A. niger isolate was resistant to voriconazole, and one A. flavus isolate was resistant to amphotericin B. Furthermore, among Candida species, three isolates of C. orthopsilosis showed high MIC values to fluconazole, two C. albicans isolates were considered fluconazole resistant and one isolate of C. parapsilosis was resistant to caspofungin and 3 isolates were resistant to fluconazole. Regarding the existence of the cases with perforated tympanic membrane and emerging species causing fungal otitis in the current report, the importance of the early physical examination, precise molecular identification, and the antifungal susceptibility evaluation is highlighted.

Species Distribution and Comparison between EUCAST and Gradient Concentration Strips Methods for Antifungal Susceptibility Testing of 112 Aspergillus Section Nigri Isolates

Aspergillus niger, the third species responsible for invasive aspergillosis, has been considered as a homogeneous species until DNA-based identification uncovered many cryptic species. These species have been recently reclassified into the Aspergillus section Nigri However, little is yet known among the section Nigri about the species distribution and the antifungal susceptibility pattern of each cryptic species. A total of 112 clinical isolates collected from 5 teaching hospitals in France and phenotypically identified as A. niger were analyzed. Identification to the species level was carried out by nucleotide sequence analysis. The MICs of itraconazole, voriconazole, posaconazole, isavuconazole, and amphotericin B were determined by both the EUCAST and gradient concentration strip methods. Aspergillus tubingensis (n = 51, 45.5%) and Aspergillus welwitschiae (n = 50, 44.6%) were the most common species while A. niger accounted for only 6.3% (n = 7). The MICs of azole drugs were higher for A. tubingensis than for A. welwitschiae The MIC of amphotericin B was 2 mg/liter or less for all isolates. Importantly, MICs determined by EUCAST showed no correlation with those determined by the gradient concentration strip method, with the latter being lower than the former (Spearman's rank correlation tests ranging from 0.01 to 0.25 depending on the antifungal agent; P > 0.4). In conclusion, A. niger should be considered as a minority species in the section Nigri The differences in MICs between species for different azoles underline the importance of accurate identification. Significant divergences in the determination of MIC between EUCAST and the gradient concentration strip methods require further investigation.

Otomycosis Due to the Rare Fungi Talaromyces purpurogenus, Naganishia albida and Filobasidium magnum

Otomycosis is a common finding in otorhinolaryngology clinics and is usually caused by species of Candida and Aspergillus, particularly black aspergilli. Meanwhile, other fungi can give rise to this infection, and the identification of these requires accurate methods. Here, we report three cases of otomycosis due to rare fungal pathogens. All the patients were young females, and manipulation of the ear canal was identified as a common potentially predisposing factor. In direct examination, filamentous fungal elements (in one case) and yeast cells (in two other cases) were seen. Culture was positive in all cases. Based on PCR-sequencing of internal transcribed spacers and β-tubulin (for mold isolate), the isolated fungi were identified as Talaromyces purpurogenus, Naganishia albida and Filobasidium magnum. By susceptibility testing of the isolates to fluconazole, itraconazole, voriconazole and amphotericin B, the lowest minimum inhibitory concentration values were observed for amphotericin B followed by voriconazole. Patients were successfully treated by a combination of antifungals and corticosteroids with no relapse over the next year, except for the case due to F. magnum, in which, despite partial recovery, a course of relapse was reported in the 1-year follow-up call.

Molecular characterization of fungi causing colonization and infection in organ transplant recipients: A one-year prospective study

Background and Purpose:

Organ transplant recipients are vulnerable to fungal infections. The aim of this study was to determine the prevalence of fungal colonization and infections among patients who underwent various transplantations and molecularly characterize the etiological agents.

Materials and Methods:

This study was conducted on candidates for transplantation in Imam Khomeini Hospital, Tehran, Iran, from April 2017 to April 2018. All patients were monitored for fungal colonization or infections before and after transplantation. Isolated fungi were identified using molecular methods.

Results:

A total of 125 patients, including 86 males and 39 females, with the mean age of 52.2 years participated in the study (age range: 15-75 years). Out of 125 patients, 84 (67.2%) cases had fungal colonization that appeared pre- and post-transplantation in 21 and 63 cases, respectively (alone or concurrent with another infection in 55 and 29 cases, respectively). In addition, a total of 39 episodes of fungal infections were diagnosed in 36 (28.8%) recipients (alone or concurrent with colonization in 7 and 29 cases, respectively). Out of the 39 fungal infections, 9 cases appeared pre-transplantation, while the other 30 cases occurred post-transplantation. However, no fungal colonization or infection was observed in 34 (27.2%) patients. Oral candidiasis (n=20) was the most common type of infection, followed by funguria (n=7), onychomycosis (n=5), candidemia (n=3), rhinocerebral mucormycosis (n=1), cutaneous mucormycosis (n=1), cutaneous aspergillosis (n=1), and peritonitis (n=1). Six yeast species were recovered from colonization cases with the dominance of Candida albicans both before and after transplantation. The observed fungal infections were caused by 11 distinct species, including the members of Candida (i.e., C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei), Aspergillus (i.e., A. oryzae and A. candidus), Rhizopus (i.e., R. oryzae and R. microsporus), Trichosporon asahii, and Trichophyton interdigitale. The results also indicated that the development of a fungal infection post-transplantation was associated with fungal colonization (r=0.0184; P=0.043).

Conclusion:

Based on the results, fungal colonization was a common finding in transplant recipients at Imam Khomeini Hospital. However, the incidence of fungal infections was comparable with those of other centers. As the oral cavity was the most common site of colonization and infection, it might be beneficial to take further care about the oral health of patients using effective mouthwash.

Recent trends in the epidemiology, diagnosis, treatment, and mechanisms of resistance in clinical Aspergillus species: A general review with a special focus on the Middle Eastern and North African region

Globally, more than billion people suffer from fungal infections each year. The early diagnosis of aspergillosis is mandatory for successful treatment outcome. As careful testing takes time, epidemiological surveillance is crucial to guide individual patient therapy and to promote a high standard of health care. In this paper, we first present current trends in the epidemiology and antifungal susceptibility patterns of Aspergillus spp. in Middle Eastern and North African (MENA) countries in order to support infectious disease specialists and health workforces in this geographic area to treat adequately patients with aspergillosis. Then we discuss the existing literature data regarding the available diagnostic tools and antifungal resistance mechanisms of Aspergillus spp. Although a limited number of studies were reviewed here, the currently available data show that Aspergillus infections are not negligible in the MENA region, and that the emergence of antifungal resistance is a growing health issue, especially among immunocompromised patients.

Molecular epidemiology of otomycosis in Isfahan revealed a large diversity in causative agents

PURPOSE

To elucidate the clinical and microbial epidemiology of otomycosis in Isfahan, Iran.

METHODOLOGY

From January 2016 to January 2017 all patients clinically suspected of otomycosis at Al-Zahra Hospital, Isfahan, Iran were recruited. Specimens were taken using sterile swabs by an otorhinolaryngologist and subjected to culture and microscopy using potassium hydroxide and Giemsa stain. Isolated fungi were identified based on morphological and molecular characteristics.

RESULTS

Otomycosis was confirmed in 97/120 patients (80.8 %). Females (72.2 %) and patients aged 30-39 years (33 %) were more commonly affected than others. Manipulation of ear canal (62.9 %) was the most common predisposing factor. Pruritus was observed in 84.54  % of the patients followed by hearing impairment (81.4 %), and most episodes were detected over the summer (50.5 %). Culture was positive for 81 (83.5  %) of confirmed cases and molds were the most prevalent causative agents (n=51, 63 %) followed by yeasts (n=19, 23.4 %) and yeast/mold mixes (n=11, 13.6 %). For the 16 remaining patients, no growth was seen in culture despite a positive result on direct examination. In total, 92 isolates (63 molds and 29 yeasts) were recovered in culture. Application of molecular methods showed 18 fungal species and the vast majority of them belonged to Aspergillus (n=53, 57.6 %) and Candida genus. Among the species involved, Candida parapsilosis (n=22, 22.7 %) and Aspergillus tubingensis (n=15, 15.5 %) were the most encountered species.

CONCLUSION

Outcomes from this study showed a different picture of prevalence, where C. parapsilosis and A. tubingensis but not Aspergillus niger were the most species encountered from patients suffering from otomycosis.

Clinical and microbial epidemiology of otomycosis in the city of Yasuj, southwest Iran, revealing Aspergillus tubingensis as the dominant causative agent

PURPOSE

Otomycosis is a mycotic infection of the external auditory canal and can be caused by a wide range of fungal species. In this study, we aimed to identify fungal isolates from patients suspected of otomycosis.

METHODOLOGY

External ear canal samples were taken from patients referred to the outpatient department of Shahid-Mofatteh Clinic in the city of Yasuj, Iran, and examined by direct microscopy and culture. DNA of the isolated fungi was tested by internal transcribed spacer PCR restriction fragment length polymorphism analysis for identification of yeasts and β-tubulin sequencing for identification of Aspergillus species.

RESULTS

Among 275 patients suspected of otomycosis, 144 cases (83 female and 61 male) were confirmed with otomycosis. For 89% (n=128) of positive cultures, microscopy was also positive, while there were no cases with a microscopy-positive and culture-negative result. The predominant predisposing factor was self-cleaning of the external ear using unhygienic tools, and the main risk occupation was 'housewife'. The most common isolated fungi were typically Aspergillus (n=120), including 73 isolates of Aspergillus section Nigri, 43 of section Flavi, 3 of section Terrei and 1 of section Fumigati. After sequencing, 44 out of 73 strains primarily identified as Aspergillus niger turned out to be Aspergillus tubingensis. Thirty-five isolates were identified as Candida, including Candida parapsilosis (n=22), Candida albicans (n=12) and Candida tropicalis (n=1).

CONCLUSION

Aspergillus tubingensis was the most common species involved in otomycosis. This work corroborates the difficulty of precise identification of species within the black Aspergilli by morphological characteristics.