Diagnosis and treatment of otomycosis in southern China

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.

Otomycosis: The foremost aetiological agent causing otitis externa and the antifungal susceptibility pattern in North-Western Iran

BACKGROUND

Otomycosis is considered a recurring fungal ear infection. The external auditory canal provides an appropriate and optimal situation for fungal growth.

OBJECTIVES

The study aimed to identify the causative agents of otomycosis and determine corresponding antifungal drug susceptibility patterns in north-western Iran.

METHODS

From October 2020 until November 2021, 200 patients attended an otolaryngology referral centre with otitis externa, and their ear discharge and debris were examined and cultured. The identification of the fungal agents was implemented by polymerase chain reaction-restriction fragment length polymorphism and sequencing. In vitro antifungal susceptibility testing of the isolates was conducted in accordance with the CLSI broth microdilution protocols.

RESULTS

The prevalence of otomycosis was measured 50.5% (n = 101/200). The majority of patients were in their forties (n = 35, 34.6%) and female (n = 57, 56.4%), and the most prevalent symptom was otalgia (56.4%). The most underlying factor was remarked manipulation employing a cotton swab (65.3%). Regarding fungus, Aspergillus section Nigri (58.57%) was the foremost isolate, followed by Aspergillus section Flavi (19.23%) and Candida parapsilosis (14.96%). The predominance of Aspergillus isolates had minimal in vitro sensitivity to tioconazole and nystatin. Candida species represented higher geometric mean minimum inhibitory concentrations (MIC) against nystatin. The MIC of three Aspergillus species isolates shown above the epidemiologic cut-off values (ECV) against itraconazole.

CONCLUSIONS

Otomycosis incidence surpassed in comparison with the previous study as the most common cause of otitis externa. The MIC distribution of Aspergillus species isolates against triazole antifungals is close to the defined ECVs and likely outrun it over time.

Analysis of the Efficacy and Safety of Intratymapanic Dexamethasone for Treating Meniere's Disease: A Randomized Controlled Trial

OBJECTIVES

Our objective was to study the efficacy and safety of intratymapanic dexamethasone (ITD) for treating in Méniere's disease in southern China.

METHODS

A total of 124 patients with Méniere's disease were randomly divided into 2 groups: ITD group (n = 62) and intratympanic lidocaine (ITL) group (n = 62). The ITD group was further randomly divided into 2 groups based on dexamethasone dosage: ITD1 (2 mg/ml) (n = 31) and ITD2 (5 mg/ml) group (n = 31). Symptom alleviation and complications were recorded after every treatment.

RESULTS

Vertigo was improved in 65% of patients who received ITD compared with 55% of patients who received ITL patients (P < .05). Three patients in the ITD2 group had from otomycosis, and 2 of these patients had a perforation; no tympanic membrane perforation was observed in the ITL and ITD1 group.

CONCLUSIONS

Compared with lidocaine, dexamethasone is more effective in alleviating vertigo, and a lower concentration of dexamethasone can reduce the occurrence of complications.

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.

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.

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.

A Comparison of Triamcinolone Acetonide Econazole Cream and Nystatin Suspension in Treatment of Otomycosis

OBJECTIVES/HYPOTHESIS

To compare the efficacy and adverse effects of triamcinolone acetonide econazole cream and nystatin suspension in the treatment of otomycosis, and to determine the clinical features, predisposing factors, and etiology of otomycosis.

STUDY DESIGN

A prospective study.

METHODS

A prospective clinical trial was conducted on 786 patients diagnosed with otomycosis. The study population was randomly divided into two treatment groups of triamcinolone acetonide econazole cream (TAEC) and nystatin suspension in a 1:1 ratio. After clearing all fungal deposits in the external auditory canal, the antimycotic drugs were locally applied for at least 2 weeks. The efficacy and adverse effects were compared between the two antifungal reagents by statistical analysis. Meanwhile, patient clinical data were collected to find out the clinical features, predisposing factors, and etiology.

RESULTS

Pruritis was the most common symptom and Aspergillus niger was the leading fungal pathogen. There was high association (44.5%) of otomycosis with a history of unclean ear picking. The cure rate was 97.6% in the TAEC group and 73.5% in the nystatin group (P < .01). Treatment with TAEC resulted in 2.4% of patients complaining of discomforts (irritant dermatitis, otalgia, or headache) versus 59.8% of patients complaining discomforts treated with nystatin (P < .01). The residue rate of antifungals was 1.9% in the TAEC group and 89.9% in the nystatin group (P < .01) at the end of treatment.

CONCLUSIONS

Thoroughly cleaning of the external auditory canal followed by local use of TAEC under endotoscope is an effective, convenient, and well-tolerated treatment for otomycosis.

LEVEL OF EVIDENCE

1 Laryngoscope, 131:E1640-E1646, 2021.

Administration of 1% topical voriconazole drops was effective and safe in the treatment of refractory otomycosis without tympanic membrane perforation

BACKGROUND

Refractory otomycosis is a common condition that is difficult to treat.

OBJECTIVES

This study aimed to evaluate the effectiveness of 1% topical voriconazole drops in the treatment of otomycosis.

METHODS

This retrospective analysis was conducted from November 2017 to November 2019. Patients who had refractory otomycosis without tympanic membrane perforation confirmed by microbial culture and fluorescent staining were included in the study. All patients were treated with 1% topical voriconazole drops hourly at daytime for 2 weeks. Evaluation of effectiveness was conducted 1 month after the completion of topical voriconazole treatment. Before and after topical voriconazole treatment, hearing tests were performed in all patients.

RESULTS

Fifty-five patients were included in this study. The reasons for refractoriness were resistant recurrence to imidazole drugs (50 cases, 90.9%) and difficulty in cleaning the external auditory canal (5 cases, 9.1%). The most common strain was Aspergillus terreus (50.9%), followed by Aspergillus flavus (29.1%), Aspergillus niger (10.9%), and Aspergillus fumigatus (9.1%). After 2 weeks of treatment with 1% topical voriconazole drops, otomycosis in all patients was resolved. There was no significant change in bone conduction before and after topical voriconazole treatment (paired t-test, P = 0.5023; linear correlation analysis, R² = 0.98; equation, y = 1.003x-0.284). Adverse effects, such as blurred vision and phototoxicity, were not observed in any patient.

CONCLUSIONS

Administration of 1% topical voriconazole drops was effective and safe in the treatment of refractory otomycosis without tympanic membrane perforation within 2 weeks.