Outer Ear Infections in Iran: A Review

Otomycosis: a systematic review and meta-analysis of prevalence and causative agents in the era of molecular diagnostics

BACKGROUND

Molecular identification of fungal agents in otomycosis can provide a more accurate diagnosis and differentiation of species compared to conventional morphological methods. Previous reviews mostly relied on studies using conventional methods to explore the prevalence and distribution of otomycosis etiologies. We aim to estimate the prevalence and distribution of causative agents in otomycosis cases confirmed with molecular methods.

METHODS

We conducted a systematic search of PubMed, Scopus, Web of Science, and Google Scholar. We selected cross-sectional studies that reported causative agents of otomycosis and used molecular methods for identification of fungi. We appraised the quality of evidence using the JBI Checklist for Prevalence Studies. Clinical and mycological data were collected, and prevalence of otomycosis was estimated by meta-analysis.

RESULTS

Twenty studies reporting 1392 fungal isolates, consisting of 46 species from 11 distinct genera, were included in this review. The prevalence of otomycosis among clinically-suspected patients was 58.3% (95% CI: 41.4-73.5%). Aspergillus (75.8%, 95% CI: 70.3-80.6%) and Candida (15.3%, 95% CI: 8.7- 25.6%) were the most common etiologies. The most frequent Aspergillus species were A. niger (n = 352, 30.9%) and A. tubingensis (n = 270, 23.7%), and the most frequent Candida species were C. parapsilosis (n = 85, 39.7%) and C. albicans (n = 66, 30.8%). The quality of evidence was assessed to be poor in all included studies.

CONCLUSIONS

Otomycosis is caused by a diverse set of species, predominantly from Aspergillus and Candida genera. Molecular identification techniques provide a more accurate understanding of the distribution of species associated with otomycosis.

CLINICAL TRIAL NUMBER

Not applicable.

Efficacy of Pyodine Soaked Gelfoam vs Single Topical Application of Clotrimazole in Treatment of Otomycosis: A Randomized Controlled Clinical Trial

To compare the efficacy of gel foam-soaked pyodine with a single topical application of clotrimazole ointment in the treatment of otomycosis. This randomized controlled trial included 90 patients who presented to ENT OPD with complaints of earache, watery ear discharge, pruritis, and ear blockage and were clinically diagnosed as a case of otomycosis via otoscopy. The external auditory canal of the patient was cleared of fungal debris via suction before treatment. In Group A, the ear canal was filled with 1% clotrimazole ointment by using an IV catheter and syringe and in Group B 10% pyodine-soaked gel foam was placed in the external auditory canal. The patients were followed up on post-treatment days 7 and 14. The results showed that out of 90 patients with otomycosis, the left ear was affected in 50(55.6%) patients and the right ear in 40(44.4%). 8(8.9%) of 90 patients had controlled preexisting diabetes mellitus. On the 7th post-treatment follow-up day, 17 (41.5%) patients in Group A and 28(66.7%) patients in Group B showed no fungal spores. Other symptom resolution was also comparable in both groups. At the 14th day follow-up 33(80.5%) patients in Group A and 38(92.7% patients in Group B showed no fungal hyphae on otoscopy. In terms of treatment response 19(46.34%) patients in Group A and 21(51.21%) patients in Group B showed good treatment response at the end of 2nd post-treatment week with a p-value of 0.798. yodine-soaked gel foam placement in the external auditory canal is a safe and effective method for the treatment of otomycosis with the efficiency of this method comparable to a single topical clotrimazole ointment application.

Topical Antibiotic-Induced Otomycosis - a Systematic Review of Aetiology and Risk Factors

Otomycosis is a chronic or subacute fungal infection of external ear accounting to 5 to 20% of external ear infection worldwide. Literature has suggested multiple local and environmental host factors associated with otomycosis, but their strength of association is not well established. We did this review to analyse otomycosis with respect to it's various common predisposing factors. Human studies reporting ototopical antibiotics with or without steroids as predisposing factors for otomycosis, or pooled data together with other predisposing factors were included. MEDLINE, EMBASE, CINAHL, the ISRCTN register, and Cochrane databases were searched for the data extraction. Critical appraisal was done using the standardized Joanna Briggs Institute's (JBI) Appraisal checklist. Random effects were used to calculate pooled estimate prevalence with 95% Confidence Intervals (CIs). Age varied in different studies with a mean age variation from 7 to 43.19. Most of the studies were conducted in tropical and sub-tropical countries. Aspergillus was the most common species isolated. The use of ototopical antibiotics with or without steroid drops [47% (95% CI, 0.38 - 0.56)] were found to be the commonest predisposing factor for otomycosis, followed by the use of a variety of oils and wax solvents [38% (95% CI,0.26 - 0.51)] and trauma to the External Auditory Canal (EAC) as a result of compulsive cleaning or instrumentation[37% (95% CI, 0.21 - 0.54)]. We suggest the need for caution and vigilance from clinicians treating patients with ototopical drops for ear infections and use of other alternative treatment like 2% acetic acid for mild cases whenever feasible.

Aspergillus otitis externa: A retrospective study of predisposing factors, treatment, and complications

Objectives

To study the predisposing factors, treatment, and complications of Aspergillus otitis externa.

Methods

A retrospective analysis of patients diagnosed with Aspergillus otitis externa at the Department of Otorhinolaryngology, Helsinki University Hospital, between January 2010 and December 2018 was performed.

Results

Of the 269 Aspergillus otitis externa (OE) patients, 96 developed otitis media (OM) and 7 developed mastoiditis. Antibiotic and steroid treatment and otological history were risk factors for Aspergillus OE. Systemic diseases and immunocompromising states were more common in mastoiditis patients. Repetitive ear cleaning and topical drugs are primary treatments, but systemic drugs and surgery were needed in resistant and invasive cases. Forty-five novel tympanic membrane (TM) perforations were reported. A strong association between Aspergillus species and final infection types was found; A. niger was the dominant species in OM and in novel TM perforations, whereas A. flavus and A. fumigatus caused mastoiditis. Some of the TM perforations persisted despite treatment. Permanent hearing impairment was associated with OM and mastoiditis.

Conclusion

As Aspergillus OE has the potential to cause acute and chronic complications, fungal OE should be suspected early on if the infection persists after conventional treatment. The identification of Aspergillus species could aid in spotting patients at risk for more severe disease and complications. Intensive local treatment is sufficient in most cases of OE and OM but effective topical antifungals are limited. Patients with Aspergillus OM and mastoiditis should be followed up for hearing impairment and permanent TM perforations after the infection resolves.

Level of evidence

Level 4 (The Oxford 2011 Levels of Evidence).

Phenotypic and genotypic characterization of Staphylococcus aureus strains isolated from otitis externa: Emergence of CC30-spa t019-SCCmec IV carrying PVL as major genotype

The increasing emergence of Staphylococcus aureus as the primary causative agent of otitis externa has been noted; however, detailed information regarding the molecular characteristics of these strains in Iran remains scarce. The current study aims to investigate both genotypic and phenotypic attributes of S. aureus strains implicated in ear infections. In the present work, we analyzed 60 S. aureus strains isolated from cases of otitis externa over a period of 45 months. The resistance patterns were determined using disk diffusion and microbroth dilution methods. All S. aureus isolates were confirmed by the nucA polymerase chain reaction assay, and their biofilm production was assessed by a microtiter plate assay. Molecular characterization of the isolates was performed using the staphylococcal cassette chromosome mec, multilocus sequence typing, and staphylococcus protein A typing methods. Overall, the results indicated that 44 out of 60 S. aureus isolates (73.3 %) were methicillin-resistant Staphylococcus aureus. Resistance to mupirocin and vancomycin was observed in 13.3 % and 1.7 % of the tested isolates, respectively. Furthermore, out of the 60 S. aureus isolates, 56 strains (93.4 %) were classified as positive biofilm strains at different levels. Twelve distinct clonal lineages were identified. The vast majority of S. aureus isolates belonged to CC30/ST30-MRSA IV/t019 (41.7 %). Among the 31 strong biofilm producers, the majority (64.5 %) belonged to CC30/ST30-MRSA IV/t019 clone. Biofilm negative isolates belonged to CC22/ST22 (2 isolates), CC8/ST585 (one isolate), and CC8/ST8 (one isolate). Our result revealed that about three-quarters of PVL-positive strains belonged to CC30/ST30. Our data confirmed the presence of MSSA strains among CC30/ST30 and CC22/ST22 isolates. The mupirocin resistant isolates (n = 8) belonged to CC8/ST585-MRSA III/t713 (37.5 %), CC8/ST239-MRSA III/t030 (25 %), CC8/ST8-MRSA IV/t008 (12.5 %), CC8/ST239-MRSA III/t037 (12.5 %), and CC22/ST22-MRSA IV/t790 (12.5 %) lineages. The VRSA strain belonged to the CC8/ST8-MRSA IV/t008 lineage, carrying the vanA determinant. iMLSB phenotypes (n = 14) were distributed across different lineages, including CC30/ST30-MRSA IV/t019 (21.5 %), CC30/ST30-MSSA/t021 (21.5 %), CC22/ST22-MSSA/t005 (14.3 %), CC8/ST239-MRSA III/t030 (14.3 %), CC22/ST22-MSSA/t1869 (7.1 %), CC22/ST22-MRSA IV/t790 (7.1 %), CC8/ST239-MRSA III/t037 (7.1 %), and CC1/ST772-MRSA IV/t10795 (7.1 %). These findings highlight significant genotypic diversity and high biofilm formation among our isolates. The frequent occurrence of the CC/ST30 clone in S. aureus strains isolated from otitis externa reflects the emergence of these lineages as a predominant clone in Iran, posing a significant public health concern.

Aetiology of ear infection and antimicrobial susceptibility pattern among patients attending otorhinolaryngology clinic at a tertiary hospital in Dar es Salaam, Tanzania: a hospital-based cross-sectional study

OBJECTIVES

To determine the aetiological pathogens causing ear infections and their antimicrobial susceptibility patterns among patients with ear complaints at a tertiary hospital in Dar es Salaam.

DESIGN

Hospital-based cross-sectional study.

SETTINGS

Otorhinolaryngology clinic at Muhimbili National Hospital, Dar es Salaam, Tanzania.

PARTICIPANTS

Patients presenting with signs and symptoms of ear infection.

MAIN OUTCOME MEASURE

Bacteria and fungi isolated from ear swab specimens of patients presenting with signs and symptoms of ear infection; and antimicrobial susceptibility patterns of isolated bacteria.

RESULTS

Two hundred and fifty-five participants were enrolled, with a median age of 31 years and an IQR of 15-49. Otitis externa was the predominant type of ear infection, accounting for 45.1%. We observed positive bacteria culture in 53.3% of study participants, in which 41% of isolates were obtained from patients with chronic suppurative otitis media. Moreover, Staphylococcus aureus (27.3%) and Pseudomonas aeruginosa (24.2%) were the most frequently isolated bacteria, while Candida spp, 12 (63.8%) and Aspergillus spp, 9 (36.2%) were the only isolated fungi. Furthermore, we report that 93% of isolated Enterobacterales were resistant to amoxicillin/clavulanic acid, and 73% were resistant to ceftazidime. In addition, we detected 34.4% extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and 44.4% methicillin-resistance S. aureus (MRSA). We also found that 22% of the bacteria isolates were resistant to ciprofloxacin, a primary topical antibiotic used in managing ear infections.

CONCLUSIONS

The findings from this study reveal that the leading aetiological agent of ear infection is bacteria. Furthermore, our findings show a significant proportion of ESBL-PE and MRSA-causing ear infections. Hence, detecting multidrug-resistant bacteria is crucial to improving ear infection management.

Numerical Simulation of Aspergillus Niger Spore Deposition in Nasal Cavities of a Population in Northwest China

Background: As common pathogens in the human respiratory tract, fungal-spore-related health risks have been challenging to evaluate properly. This paper presents numerical simulations of particle deposition of Aspergillus niger spores in human nasal cavities. Methods: 30 healthy adults (including 60 nasal chambers) who lived in northwest China were recruited to conduct a nasal cavity numerical simulation using computational fluid dynamics–discrete phase model (CFD-DPM). The deposition rate in each anatomic area and its influencing variables, such as body position and respiratory flow rate, were analyzed. Results: (1) Under a resting condition, only about 5.57% ± 1.51% Aspergillus niger spores were deposited in the nasal cavity, while most of them escaped from the nasopharynx, and 0.31% ± 0.20% spores entered the maxillary sinus; (2) under an exercising condition, spores deposited in the nasal cavity were about 2.09 times as many as that in the resting state; (3) in a lying position, the A. niger spores deposited evenly on the lateral wall of the nasal cavity and the sinus when compared with a standing position. However, the deposition rate in each anatomic area did not change significantly.

A Comparison of Antifungal Drugs and Traditional Antiseptic Medication for Otomycosis Treatment: A Systematic Review and Meta-Analysis

Objectives/Hypothesis: To perform a systematic review and meta-analysis to compare the efficacy of and complications associated with antifungal drugs and traditional antiseptic medication for the treatment of otomycosis.

Data Sources: The PubMed, EMBASE, GeenMedical, Cochrane Library, CBM, CNKI, VIP and other databases were searched from January 1991 to January 2021.

Methods: The systematic literature review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Randomized controlled trials (RCTs) and non-randomized studies (case-control, cohort, and case series) were included to assess the topical use of antifungal drugs and traditional antiseptic medication in patients with otomycosis. The research subjects were patients who were clinically diagnosed with otomycosis and whose external auditory canal secretions were positive for fungi. Funnel plots were used to detect bias, and the Q test was used to assess heterogeneity. The random-effects model was used for meta-analysis. The t-test was used to assess significance.

Results: Of the 324 non-duplicate studies screened, 16 studies met the criteria for full-text review, and 7 were included in the meta-analysis. Four studies reported recovery conditions (P = 0.01). Six common complications after medication use were compared, and there were no significant differences. The authors further conducted subgroup analysis according to complications. The differences in the rates of ear distension (P = 0.007), earache (P = 0.03) and tinnitus (P = 0.003) were statistically significant.

Conclusion: The results of this meta-analysis and literature review showed that antifungal drugs and traditional antiseptic medication were effective in relieving symptoms in patients with otomycosis, and the two treatments were associated with different complications. Otolaryngologists have the option to use one medication or a combination of two drugs on the basis of the condition. Future research in this area should include RCTs with long-term follow-up to guide the development of otomycosis guidelines to overcome some of the weaknesses found in the literature.

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/#myprospero.

Molecular Diversity of Aspergilli in Two Iranian Hospitals

The Aspergillus species are main causative agents of various infections such as invasive aspergillosis (IA) in immunocompromised patients and these infections have high mortality rates. In this study, we provide insight in the species causing aspergillosis in Iran based on morphology and sequence data. Clinical (n = 117) and environmental isolates (n = 54) collected during 2010-2016 from University hospitals in Mashhad and Tehran (Iran) were identified both morphologically and molecularly using partial calmodulin (CaM) gene sequences. Clinical cases were identified based on EORTC/MSG criteria. Aspergillus flavus (n = 96, 55%) was the most prevalent species among the clinical and environmental isolates while A. fumigatus (n = 13, 7.5%) ranked fourth after A. tubingensis (n = 23, 13%) and A. welwitchiae (n = 18, 10%). Species such as A. tubingensis, A. welwitschiae, A. fumigatus, A. sydowii, A. neoniger and A. terreus were present in both clinical and environmental samples indicating the possible environmental source of infections. Interestingly, A. niger was isolated only once. Furthermore, 13 other rare and cryptic Aspergillus species were detected. Pulmonary and respiratory disorders (n = 33), followed by transplantation (n = 23), invasive fungal rhinosinusitis (n = 14), and haematological malignancies (n = 12) were major predisposing factors. According to EORTC/MSG criteria, there were 43 probable cases identified followed by 36 cases for each of proven and possible ones. Correct molecular identification will be useful for further epidemiological studies.

Role of Clotrimazole in Prevention of Recurrent Otomycosis

Otomycosis is one of the relatively common diseases in the world which is caused by different fungi especially saprophytes. Concerning the relapse of this disease in a number of individuals, the present study was performed to evaluate the inhibitory effect of clotrimazole drop in the relapse of otomycosis. Clinical samples were taken by an ENT specialist from patients suspicious of having otomycosis. A part of these samples were stained, and others were cultured. The diagnosis of otomycosis was made on the basis of the recognizable and characteristic appearance of fungal hyphae or mycelium and fruiting bodies and/or conidiophores under microscopic examination. Patients with suspected otomycosis are not at risk of recurrence after treatment with clotrimazole drops. Out of the 161 individuals in whom definite diagnosis of otomycosis was made, the most affected individuals were, in the age range of 40–49 years, women, urban citizens, and housewives. Pruritus and diminished hearing were the main complaints of the patients. Aspergillus niger and A. flavus as well as Candida albicans were the main causes of the disease. The relapse of disease was observed in only five patients (3.1%), where A. niger was the main fungus. Most relapses were observed in women and in those with diminished hearing, manipulating the ears, ulcers in the canal, and tympanum. Our results suggested that usage of clotrimazole can be effective in reducing the relapse of otomycosis, and concerning the high cost of treating otomycosis while the low cost of using clotrimazole, usage of this drop is recommended to reduce the relapse of otomycosis.