Ototoxicity of Ototopical Drops—An Update

Determinants of Cochlear Dysfunction in Chronic Otitis Media: Mucosal Disease

The nature of association between chronic otitis media (COM)-mucosal disease and sensorineural hearing loss is controversial. Identifying the risk factors which influence the bone conduction threshold in these patients can help the clinician in counselling the patients for surgery at the earliest to achieve optimum hearing outcomes. The present study was undertaken to determine the association between COM-mucosal disease and cochlear dysfunction. The study also aimed at identifying the determinants and their influence on the bone conduction thresholds of the diseased ear. In this study, 72 patients with unilateral chronic otitis media-mucosal disease were enrolled consecutively. All patients were enquired in detail about their presenting ear symptoms. All the patients underwent a pure tone audiogram in a sound treated room. Patients were categorised into two groups according to the presence of conductive hearing loss only or with a sensorineural component. The bone conduction thresholds were calculated and compared for frequencies at 0.5, 1, 2 and 4 kHz. The average hearing threshold for air conduction and bone conduction were calculated across 0.5, 1 and 2 kHz. Bone conduction threshold more than 20 decibels (dB) in any of the frequencies were considered significant and indicative of having sensorineural hearing loss component. The contralateral healthy ear served as control to cancel out the confounding factors such as presbyacusis, noise induced hearing loss, congenital hearing loss, etc. Multivariate linear regression models were used to evaluate the relationships between bone conduction thresholds and chronic otitis media-mucosal disease. In the present study, 18.05% of participants had a sensorineural component. The difference between the bone conduction threshold in the diseased ear and normal ear ranged from 5.41 dB at 0.5 kHz to 3.77 dB at 4 kHz (p < 0.001). Bone conduction thresholds at 4 kHz were greater than that for speech frequencies (p < 0.5). 84.6% of participants with sensorineural component had a disease duration of less than 5 years and the remaining 15.4% had a duration of greater than 15 years. There was no statistically significant difference in the incidence of sensorineural component based on the site of the perforation (p = 0.341). 21.9% of participants who used topical antibiotic drops developed a sensorineural component, while 15% of participants who did not use antibiotic ear drop preparation developed a sensorineural component. Multivariate linear regression analysis revealed that increasing age was the only factor associated with increase in bone conduction thresholds of the diseased ear (p = 0.002). Chronic otitis media- mucosal disease appears to be associated with higher bone conduction thresholds, signifying cochlear dysfunction. A statistically significant higher bone conduction thresholds are seen across 0.5 to 4 kHz in the diseased ears compared to the normal ears, signifying the vulnerability of the inner ear against chronic otitis media. In our analysis increasing age is the most significant predisposing factor associated with higher bone conduction thresholds. Higher frequencies are more affected than lower speech frequencies. Sensorineural hearing loss can occur early in the disease process and early surgical intervention in COM-mucosal disease is recommended to prevent increase in bone conduction thresholds and achieve optimum hearing outcomes.

Ototoxicity of Topical Antibiotic Ear Drops in Chronic Suppurative Otitis Media in Humans: A Review of the Literature

An electronic search of the literature was performed for reported cases of ototoxicity associated with the use of topical antibiotic ear drops in humans. The dosage, duration, and type of ototoxic preparations involved were recorded. Due to the scant quantity of low-quality information that is currently available, there was uncertainty about the usefulness of topical antibiotics in enhancing the resolution of ear discharge in patients with chronic suppurative otitis media. However, despite this uncertainty, there are some data to show that using topical antibiotics in comparison to a placebo or in conjunction with a systemic antibiotic may be useful. Additionally, there is ambiguity regarding the relative efficacy of various kinds of antibiotics; it is impossible to say with absolute certainty whether quinolones are superior to or inferior to aminoglycosides. Although the adverse impact profiles of these two classes of chemicals varied, there are not enough data from the included trials to draw any conclusions about them. Negative effects were generally underreported.

Serum Immunoglobulin E and Serotonin levels in Chronic Supporative Otitis Media Patients with and without treatment

Objective:

To determine the serum immunoglobulin E and serotonin levels of patients with chronic suppurative otitis media (CSOM) with and without treatment.

Methods:

This is a case-control study carried out in ENT ward of Jinnah Postgraduate Medical Centre Karachi Pakistan from May to September 2018.. Sample (n=160) was divided into four groups (40 individuals per group) as G1: control negative (group-1 without any disease), G2: positive control (patients didn’t received medicines), G3: group (patients treated with co-amoxicillin 1000mg per day) and G4: group (patients treated with ciprofloxacin1000mg per day). After treatment period of One week serum immunoglobulin E and serotonin concentrations were evaluated by Elisa method at 450nm.Statistical evaluation was carried out using one-way ANOVA (p<0.05) followed by post hoc (tukey test) for further group comparison. In order to find out correlation between IgE and serotonin with CSOM Pearson’s correlation was applied.

Results:

There was no significant (p > 0.05) association found between genders with serotonin as well as with IgE levels in CSOM patients. One way ANOVA showed significant difference (p<0.05) for IgE and serotonin levels and post hoc (tukey test) showed significant higher of IgE levels in CSOM patients of G2 positive control (diseased patients) was observed when compared to the control negative group (healthy individuals) and also from treated groups of G3 and G4. This also showed that serotonin levels were significantly low in G2 (positive control) as well as in treated groups of G3 and G4 in contrast with healthy individuals of group G1.

Conclusion:

Antibiotics may revert the higher levels of IgE but cannot attenuate the decreased levels of neurotransmitter (serotonin) like healthy individuals, therefore, depression levels of CSOM patients should be monitored, scored and attenuated with proper intervention of antidepressants or counseling.

Characterization of Ciprofloxacin Resistance Levels: Implications for Ototopical Therapy

HYPOTHESIS

Ciprofloxacin-resistant pathogens are inhibited by high concentrations of ciprofloxacin found in commercially-available ototopical solutions.

BACKGROUND

Ciprofloxacin-resistant pathogens in otitis media are currently treated with ototopical ciprofloxacin suspensions. This is done irrespective of laboratory-reported ciprofloxacin susceptibility, under the assumption that the high concentration of ciprofloxacin applied topically is sufficient to overcome antimicrobial resistance.

METHODS

We evaluated 34 ciprofloxacin-resistant isolates consisting of Staphylococcus aureus, Pseudomonas aeruginosa, Corynebacterium spp., and Turicella otitidis. Ciprofloxacin minimum inhibitory concentration (MIC) assays and clinical ototopical solution minimum bactericidal concentration (CMBC) assays were performed.

RESULTS

Amongst the ciprofloxacin-resistant isolates, ciprofloxacin MICs ranged from 8 to 256 mcg/ml (mean: 87.1 mcg/ml) and CMBCs ranged from 23.4 to 1500 mcg/ml (mean: 237.0 mcg/ml). There were no significant differences with respect to MIC in comparing P. aeruginosa versus Corynebacterium spp. (mean: 53.3 versus 55.2, p = 0.86), S. aureus versus P. aeruginosa (mean: 128.0 versus 53.3, p = 0.34), and S. aureus versus Corynebacterium spp. (mean: 128.0 versus 55.2, p = 0.09). The correlation between ciprofloxacin MIC and CMBC was poor (Pearson's r = -0.08, p = 0.75).

CONCLUSIONS

Ciprofloxacin-resistant pathogens commonly recovered from otitis media exhibit highly variable ciprofloxacin MIC and CMBC levels. Ciprofloxacin was able to inhibit growth in all isolates tested at MIC levels less than or equal to 256 mcg/ml; however, CMBC's up to 1500 mcg/ml were observed within that same group. The clinical relevance of these in vitro MICs is unclear due in part to higher bactericidal concentrations (CMBC) in several strains. Our results suggest that treatment failures may be due to a combination of factors rather than high-level resistance alone.

Potential Ototopical Antiseptics for the Treatment of Active Chronic Otitis Media: An In Vitro Evaluation

OBJECTIVES

Primary: to compare, in vitro, the antimicrobial activity of different antiseptic agents versus quinolone drops, against the common organisms of chronic otitis media.Secondary: to examine the possible role of pH on the antimicrobial activity of the antiseptic solutions.

METHODS

Three antiseptic powders (boric acid; iodine; and a 1:1 combination of these two) and four solutions (2% boric acid; 2% acetic acid; 3.25% aluminum acetate; and 5% povidone iodine) were tested against five bacteria and two fungi common in chronic otitis media, using both agar plates and the modified broth dilution method. These results were compared with the antimicrobial activity of quinolone drops.The potential role of pH of solutions was tested by reducing the acidity of the agents and repeating the broth dilution.

RESULTS

Of the powders, iodine, and iodine/boric acid combined, are very effective against all organisms. Boric acid powder showed moderate effectiveness against all organisms. All solutions performed poorly on the agar plates. 5% povidone iodine has good effectivity when tested with the broth dilution method. 3.25% aluminum acetate had the best activity against Pseudomonas aeruginosa.

CONCLUSION

Boric acid powder and 5% povidone iodine solution show promise for clinical use. Boric acid powder has proven clinical effectiveness. 5% povidone iodine requires further clinical research. Although very effective in vitro, iodine powder is toxic to tissues and cannot be recommended for clinical use. The pH of solutions does not seem to play a significant role in their antimicrobial activity in vitro.

Is Pool Water Disinfectant (Hydrogen Peroxide-Silver Composition) Ototoxic in Rats?

OBJECTIVES

The purpose of our study was to evaluate whether hydrogen peroxide and silver composition (H202-Ag) used in pool water disinfectant is ototoxic to individuals with tympanic membrane perforation.

MATERIALS AND METHODS

The tympanic membranes of both ears of 14 Wistar-type albino female rats were perforated. Since topical application was performed, the right and left ears were categorized as two subgroups (a: right ear, b: left ear). Baseline auditory brainstem response (ABR) was measured. The groups were classified according to topical applications performed as Ia (30 mg/L H202-Ag), Ib (saline), IIa (70 mg/L H202-Ag), and IIb (saline). The topical applications were performed for 30 min/day for 10 days. The ABR was measured 24 hours after the last application, and the animals were sacrificed. Bilateral temporal bones were examined using light microscopy.

RESULTS

An apparent rise in the hearing thresholds of the groups Ia and Ib was not observed. However, there was an apparent rise in the hearing thresholds of the group IIa, which supports ototoxicity. According to histopathology results, there weren't any pathological findings in groups Ia and Ib and did not display special features, but a neurotoxic effect was observed in group II.

CONCLUSION

Our study shows that the H202-Ag used in pool water disinfection can have ototoxic and neurotoxic effects, particularly at high concentrations.

Auditory and Histopathological Effects of Topical Mercurochrome Treatment in Rats with Tympanic Membrane Perforation

OBJECTIVES

Topical treatment is first choice in the treatment of uncomplicated chronic otitis media. It was intended to assess auditory and histopathological safety of ototopical use of mercurochrome solution in rats with induced tympanic membrane perforation.

MATERIALS AND METHODS

The study was conducted on 21 female Wistar-Albino rats which were randomly assigned into 3 groups. In all rats, perforation was performed at right tympanic membrane. Distortion product otoacoustic emissions (DPOAEs) measurements were performed at frequencies of 2000, 3000 and 4000 Hz (with L1/L2: 70 /70 dB at 2f1-f2 frequency; f2/f1 ratio: 1:22) before recovery from anesthesia and signal-to-noise ratio (SNR) were recorded. Normal saline, 2% mercurochrome and gentamicin were given to group 1, 2 and 3 twice daily over a week, respectively. Rats were sacrificed after DPOAE measurements on day 14. Right temporal bone specimens were examined under light microscope after processing.

RESULTS

Based on DPOAE results, there was no significant difference among groups before treatment. On day 14, significant differences were found in DPOAE measurements at 3000 and 4000 Hz, and in mean SNR values in 2% mercurochrome and gentamicin groups when compared to normal saline group while no significant difference was detected at 2000 Hz among groups. In addition, significant degeneration was detected in Corti organs, spiral ganglions and stria vascularis in groups 2 and 3.

CONCLUSION

In this study, it was observed that mercurochrome use in external otitis and otitis media with tympanic membrane perforation could cause ototoxicity and concluded that the solution should be used cautiously.

Topical ear drop self-medication practice among the Ear, Nose, and Throat patients in Ido Ekiti, Nigeria: A cross - sectional study

Background:

Self-medication is a common habit in our country; Nigeria, especially among patients with otorhinolaryngological disorders. Medication when taken wrongly may bring dire consequences to the individual, such as masking developing diseases and may cause many other undesirable effects. The aim of this study was to determine the prevalence and to analyze topical ear drop self-medication practices among respondents attending the Ear, Nose, and Throat Clinic of Federal Teaching Hospital Ido Ekiti, Nigeria.

Design and Methodology:

A 6-month hospital based cross-sectional study was conducted among patients who were seen in the Ear, Nose, and Throat facility of Federal Teaching Hospital, Ido Ekiti from July to December 2016 to determine topical ear drop self-medication practices. A pretested semi-structured questionnaire was used to obtained information from respondents.

Results:

A total of 162 respondents out of 493 patients seen during the study had otological problems. Of which 107 (66%) respondents had engaged in self-medication with topical ear drops. Their ages ranged between 2 and 83 years with a mean age of 36.6 ± 19.1 years. There were 75 males and 87 females. The major reason for self-medication was that their ailments were minor in about 40.2% and the most common indication for self-medication was ear blockage with hearing impairment (33.6%). Pharmacy/chemist shops (42%) were major sources of information for those that self-medicated. Chloramphenicol and gentamycin were the major drugs that were used by the respondents.

Conclusion:

Majority of the respondents in this study practiced self-medication using different topical ear drops. Major source of information on the topical ear drops used was from pharmacy/chemist shops. There is a need for adequate public health education to create awareness among people on the danger of self-medication and to enact or enforce the law to reduce access to over the counter drugs. Healthcare should be made available and avoidable at primary health-care level.

Efficacy and safety of eberconazole 1% otic solution compared to clotrimazole 1% solution in patients with otomycosis

PURPOSE

To demonstrate non-inferiority of eberconazole 1% otic solution to clotrimazole 1% solution, and to compare their safety profiles in the treatment of otomycosis.

MATERIALS AND METHODS

Multicenter, randomized, double-blind, active treatment-controlled phase 3 clinical trial. One hundred and ninety patients with diagnosis of otomycosis were randomly assigned to eberconazole 1% otic solution or clotrimazole 1% solution.

RESULTS

Baseline characteristics were comparable between both groups for age, gender, ethnicity, and clinical variables. Both study groups had high complete response rates: 81.8% in the eberconazole group and 83.5% in the clotrimazole group. Although non-inferiority of eberconazole relative to clotrimazole could not be demonstrated, a post-hoc sensitivity analysis demonstrated that eberconazole 1% otic solution was not inferior to clotrimazole 1% solution for the primary efficacy endpoint. Secondary endpoints also demonstrated that eberconazole 1% and clotrimazole 1% solutions were therapeutically similar at the end of the study. The incidence of adverse events was similar in both groups, and none had related AEs and withdrawals due to an AE.

CONCLUSIONS

Eberconazole 1% otic solution is an efficacious and safe option to treat otomycosis-affected patients in the general practice.

Otic drug delivery systems: formulation principles and recent developments

Disorders of the ear severely impact the quality of life of millions of people, but the treatment of these disorders is an ongoing, but often overlooked challenge particularly in terms of formulation design and product development. The prevalence of ear disorders has spurred significant efforts to develop new therapeutic agents, but perhaps less innovation has been applied to new drug delivery systems to improve the efficacy of ear disease treatments. This review provides a brief overview of physiology, major diseases, and current therapies used via the otic route of administration. The primary focuses are on the various administration routes and their formulation principles. The article also presents recent advances in otic drug deliveries as well as potential limitations. Otic drug delivery technology will likely evolve in the next decade and more efficient or specific treatments for ear disease will arise from the development of less invasive drug delivery methods, safe and highly controlled drug delivery systems, and biotechnology targeting therapies.

Lugol's solution eradicates Staphylococcus aureus biofilm in vitro

OBJECTIVES

The aim of the study was to evaluate the antibacterial efficacy of Lugol's solution, acetic acid, and boric acid against Staphylococcus aureus biofilm.

METHODS

The efficacy of Lugol's solution 1%, 0.1%, and 0.05%, acetic acid 5% or boric acid 4.7% for treatment of Staphylococcus aureus biofilm in vitro was tested using 30 clinical strains. Susceptibility in the planktonic state was assessed by disk diffusion test. Antiseptic effect on bacteria in biofilm was evaluated by using a Biofilm-oriented antiseptic test (BOAT) based on metabolic activity, a biofilm bactericidal test based on culturing of surviving bacteria and confocal laser scanning microscopy combined with LIVE/DEAD staining.

RESULTS

In the planktonic state, all tested S. aureus strains were susceptible to Lugol's solution and acetic acid, while 27 out of 30 tested strains were susceptible to boric acid. In biofilm the metabolic activity was significantly reduced following exposure to Lugol's solution and 5% acetic acid, while boric acid exposure led to no significant changes in metabolic activities. In biofilm, biocidal activity was observed for Lugol's solution 1% (30/30), 0.1% (30/30), and 0.05% (26/30). Acetic acid and boric acid showed no bactericidal activity in this test. Confocal laser scanning microscopy, assessed in 4/30 strains, revealed significantly fewer viable biofilm bacteria with Lugol's solution (1% p < 0.001, 0.1% p = 0.001 or 0.05% p = 0.001), acetic acid 5% for 10 min (p = 0.001) or 30 min (p = 0.015), but not for acetic acid for 1 min or boric acid.

CONCLUSION

Lugol's solution 1.0% and 0.1% effectively eradicated S. aureus in biofilm and could be an alternative to conventional topical antibiotics where S. aureus biofilm is suspected such as external otitis, pharyngitis and wounds.

Ototoxicity of boric acid powder in a rat animal model

Introduction

Boric acid, which has antiseptic and acidic properties, is used to treat external and middle ear infections. However, we have not found any literature about the effect of boric acid powder on middle ear mucosa and inner ear.

Objective

The purpose of this study is to investigate possible ototoxic effects of boric acid powder on cochlear outer hair cell function and histological changes in middle ear mucosa in a rat animal model.

Methods

Twenty healthy, mature Wistar albino rats were used in this study. The rats were divided into two groups, Group A and Group B, each of which consisted of 10 rats. Initially, the animals in each group underwent distortion product otoacoustic emissions testing of their right and left ears. After the first distortion product otoacoustic emissions test, a surgical microscope was used to make a small perforation in both ears of the rats in each group, and a second distortion product otoacoustic emissions test was used to measure both ears in all of the rats. Boric acid powder was applied to the right middle ear of the rats using tympanic membrane perforation, and the distortion product otoacoustic emissions were measured immediately after the boric acid powder application. The histological changes and distortion product otoacoustic emissions were evaluated three days later in Group A and 40 days later in Group B.

Results

No significant differences were found at all of the distortion product otoacoustic emissions frequencies. In Group A, mild inflammation of the middle ear mucosa was found on the third day after boric acid powder application. In Group B, boric acid powder caused mild inflammatory changes on the 40th day, which declined over time. Those changes did not lead to significant fibrosis within the mucosa.

Conclusion

In rats, boric acid powder causes mild inflammation in middle ear mucosa and it has no ototoxic effects on cochlear outer hair cell function in the inner ear of rats.

Otitis media: an update on current pharmacotherapy and future perspectives

INTRODUCTION

Acute otitis media (AOM) is the most common childhood bacterial infection and also the leading cause of conductive hearing loss in children. Currently, there is an urgent need for developing novel therapeutic agents for treating AOM.

AREAS COVERED

Structured search of current literature. PubMed was searched for published literature in areas of pharmacotherapeutics, preventive therapies and complementary treatments for OM. The intent of this review is to provide a comprehensive evaluation of therapeutics for AOM, including preventive modalities and complementary medicine.

EXPERT OPINION

the management of AOM in young children is still evolving and depends on patterns of bacterial colonization and antimicrobial resistance in the community. The introduction of vaccinations against potential respiratory tract pathogens has altered the frequency of recovery of pathogens causing ear infections in children. Even though not all patients require antimicrobial therapy to overcome their infection, these agents improve symptoms faster and lead to fewer treatment failures. Further studies are warranted to evaluate which patients would best benefit from antimicrobial therapy.

Steroids in aminoglycoside-containing ear drops: do they reduce cochlear toxicity?

OBJECTIVES/HYPOTHESIS

To determine whether betamethasone (BM) reduces the cochlear toxicity of otic gentamicin (GM) if given together.

STUDY DESIGN

Controlled animal study.

METHODS

Thirty-four mice were assigned at random to receive intratympanic injections of either 0.1 % BM (11 mice), 0.3% GM (13 mice), or a combination of both (GM/BM) with benzalkonium chloride (10 mice) in the left ear (treated) and saline on the right (untreated). Six injections were given on alternate days. Auditory brainstem response thresholds were assessed at 1 month, 2 months, and >2 months.

RESULTS

There was a significantly greater degree of hearing loss in the BM-treated ears compared to the untreated ears (6.48 dB hearing loss, P = .007) and in the GM-treated ears compared to untreated ears (6.59 dB hearing loss, P = .010,). However, otic GM/BM and benzalkonium chloride did not cause significant additional hearing loss compared with the untreated ears (3.56 dB hearing loss, P = .242).

CONCLUSIONS

Our data suggest that hearing loss caused by GM otic drops may be reduced by the inclusion of BM and benzalkonium chloride. Our finding that BM alone was associated with hearing loss suggests that the benzalkonium chloride may be the protective agent in combination otic drops.

Panel 7: Treatment and comparative effectiveness research

BACKGROUND AND OBJECTIVES

Otitis media (OM) is one of the most common reasons for antibiotic treatment in children. Controversies regarding antibiotic treatment for OM have accumulated in the past decade, and there seem to be more dilemmas than certainties. The objectives of this article are to provide the state-of-the art review on achievements in treatment of all different stages of OM, including acute otitis media (AOM), otitis media with effusion (OME), and chronic suppurative otitis media, and to outline the future research areas.

DATA SOURCES

PubMed, Ovid Medline, the Cochrane Database, and Clinical Evidence (BMJ Publishing).

REVIEW METHODS

All types of articles related to OM treatment published in English between January 2007 and June 2011 were identified. A total of 286 articles related to OM treatment were reviewed by the panel members; 114 relevant quality articles were identified and summarized.

RESULTS

New evidence emerged on beneficial results of antibiotic treatment, compared with observation of AOM in young children who were diagnosed based on stringent criteria. In OME, the main results were related to a nonsignificant benefit of adenoidectomy versus tympanostomy tube placement alone in the treatment of chronic OME in younger children. Other modalities of OM treatment were studied and described herein.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

Significant progress has been made in advancing the knowledge on the treatment of OM. Areas of potential future research have been identified and outlined.

Effects of topical oxiconazole and boric acid in alcohol solutions to rat inner ears

OBJECTIVE

The aim of this study is to evaluate the ototoxicity of topical oxiconazole and boric acid in alcohol solutions.

STUDY DESIGN

Prospective controlled animal study.

SETTING

Research laboratory.

METHOD

Fifty adult Wistar albino rats were divided into 5 groups consisting of 10 animals each. The right tympanic membranes were perforated, and baseline and posttreatment distortion product otoacoustic emission (DPOAE) measurements were performed.

RESULTS

The solutions were applied through the external ear canal to the middle ear twice a day for 14 days. The rats in group I and group II received 0.1 mL of oxiconazole-containing solution drops and 4% boric acid in alcohol solution drops, respectively. Group III received gentamicin solution (40 mg/mL) (ototoxic control), group IV received saline solution, and group V was followed without any medication. The baseline DPOAE results of the right ears of all animals tested were normal. Animals in groups I, II, IV, and V showed no statistically significant change in the DPOAE amplitudes. The rats in the gentamicin group showed a significant decrease.

CONCLUSION

This study demonstrates that topically used oxiconazole and boric acid in alcohol solutions to the middle ear appear to be safe on the inner ear of rats. The safety of these drugs has not yet been confirmed in humans. Caution should be taken when prescribing these drugs, especially to patients who had tympanic membrane perforation. Ear drops should be chosen more carefully in an external ear infection for patients with tympanic membrane perforation to avoid ototoxicity.

The ototoxic effect of intratympanic terbinafine applied in the middle ear of rats

Background

Otomycosis is defined as an infection of the external ear canal with fungal agents. The treatment of the disease is cleansing and drying of the external ear canal, identification and treatment of any predisposing factors and application of topical antifungal agents. Terbinafine is used as an antifungal agent to treat otomycosis. We proposed to investigate the probable ototoxic effect of terbinafine solution on auditory brain stem response (ABR) and distortion product otoacoustic emission (DPOAE) when applied intratympanically in the middle ear of rats.

Methods

The experiment was performed on 30 female Wistar albino rats. Thirty animals were divided into three groups of 10 animals each. 1% terbinafine solution was administered to the first group (group T). The second group (group G) was administered 40 mg/ml gentamicin solution (ototoxic control). The third group (group S) was administered saline solution (negative control). Baseline DPOAE measurements and ABR testing from the left ears were obtained from the animals in all groups under general anesthesia. Ear solutions were applied in the middle ear intratympanically with a dental needle. Treatment was initiated after baseline measurements and repeated once every two days for fifteen days.

Results

Pre and post-treatment DPOAE responses for all tested frequencies of group T and Group S showed no statistically significant difference. However, the group G demonstrated a significant change in ABR thresholds and DPOAE responses.

Conclusions

Terbinafine solution is a broad spectrum antifungal agent effective in the treatment of otomycosis. The present study demonstrated that its direct administration in the middle ear of rats does not affect inner ear function as measured by ABR and DPOAE responses.

Topical treatment of chronic suppurative otitis media

Chronic suppurative otitis media (CSOM) is a chronic inflammation of the middle ear and mastoid cavity presenting with ear discharge or otorrhea through a non-intact tympanic membrane. CSOM is the most common cause of childhood hearing impairment in developing countries. Accurate diagnosis depends on a high index of suspicion, micro-otoscopic examination, and judicious use of imaging as required. CSOM can be classified into 3 types: tubotympanic, atticoantral, and post-tympanostomy tube insertion. Aerobes, anaerobes and fungi are all potential pathogens in CSOM. This review summarizes the results of recent studies on the bacteriology of CSOM, biofilms, and the role of the nasopharynx pathogens that may have important implications for the treatment of this important pathology; that is often associated with misdiagnosis or delayed diagnosis. Particular emphasis will be placed on topical treatment options including choices of antibiotic, antifungal, and antiseptic agents, delivery technique, spectrum of activity, and risk of ototoxicity.

Is there an ototoxicity risk from Cortisporin and comparable otic suspensions? Distortion-product otoacoustic emission findings

The purpose of this investigation was to use distortion-product otoacoustic emission (DPOAE) testing to address the issue of possible ototoxicity from the use of neomycin/polymyxin B/hydrocortisone otic suspension following tympanostomy tube placement. We retrospectively reviewed our clinical records and identified 36 children (52 ears) who had met our three study criteria: (1) unilateral or bilateral placement of transtympanic ventilation tubes, (2) treatment for 3 to 5 days with neomycin/polymyxin B/hydrocortisone drops, and (3) postoperative evaluation by DPOAE testing. We identified another set of 36 children (52 ears) who had not received these drops and who had not undergone tube placement but who had been evaluated by DPOAE testing to serve as a control group. We found no significant differences in DPOAE amplitudes between the treatment and control groups. These findings are consistent with decades of clinical experience indicating that neomycin/polymyxin B/hydrocortisone otic suspension is safe when used responsibly.

Chronic suppurative otitis media: optimizing initial antibiotic therapy in a tertiary care setup

A prospective study was done to determine the clinico-microbiological profile and the antibiogram of patients with chronic suppurative otitis media. Ninety-four patients presenting with tympanic perforation and ear discharge of more than 3 months were studied. Middle ear swabs obtained aseptically were processed for culture and the isolates identified by standard procedures. Antimicrobial susceptibility testing of the aerobic bacterial isolates was performed by disc diffusion method according to clinical laboratory standards institute guidelines. Patients in the age group of 21-30 years were more commonly affected (22.3%). Male:Female ratio was 2:1.4. Of the 94 patients, 64 (68.1%) had tubo-tympanic disease and rest 30 (31.9%) presented with attico-antral disease. Monomicrobial flora was seen in 55 (58.5%) samples, 28 (29.8%) yielded polymicrobial growth and 11 (11.7%) samples were sterile. A total of 115 microbial isolates (86 aerobic bacteria, 18 anaerobic bacteria and 11 fungi) were obtained. Pseudomonas aeruginosa (32.2%) was the most common isolate followed by Staphylococcus aureus (17.4%). Amongst anaerobes, gram positive cocci were more commonly isolated (38.9%). Aspergillus spp. (72.7%) were the most common fungus isolated. Most of the Pseudomonas aeruginosa isolates (25, 67.6%) were susceptible to all the antibiotics. Among the commonly used topical agents in the treatment of CSOM, tobramycin was the most effective (83.8%), followed by gentamicin (78.1%), ciprofloxacin (75.6%) and neomycin (3.5%). Periodic monitoring of the microbiological profile along with their sensitivity pattern is essential for formulating an effective antibiotic policy for CSOM.

Ototoxicity caused by topical administration of gentamicin versus tobramycin in rabbits

AIM

To investigate the possible differences in cochleotoxic effects in rabbits between twice-daily administration of topical gentamicin and tobramycin throughout the perforated tympanic membrane with the use of distortion-product otoacoustic emissions (DPOAEs).

MATERIALS AND METHODS

Twenty female rabbits were studied prospectively daily for 21 days. The rabbits' ears were divided into two groups: right and left ear groups. Twice-daily for 21 days after paracentesis, 0.3% gentamicin was administered topically in the left ears, and 0.3% tobramycin was administered topically in the right ears. For 21 days, the cochlear activity of the right and left ears of all rabbits was examined every 7 days using DPOAEs. The numerical values of the distortion product (DP) intensity recorded on days 7, 14 and 21 of drug administration were compared between the two groups.

RESULTS

Cochlear activity was reduced earlier in the gentamicin group in the 2-4kHz frequencies compared to the tobramycin group in the second DPOAE measurement (day 7 of the experiment). In two rabbits in the gentamicin group, the third DPOAE measurement showed that cochlear activity was reduced in all frequencies. In six rabbits in the tobramycin group, the third DPOAE measurement showed that cochlear activity was reduced in all frequencies. There was no statistical significance between the two groups except day 7 in the 2 and 3kHz frequencies (p<0.05).

CONCLUSION

We concluded that low frequencies (2 and 3kHz) are more sensitive to the administration of topical gentamicin than to topical tobramycin. Early cessation of tobramycin drops may be minimally cochlear toxic compared to gentamicin within the first 7 days when these drugs are misused in treating chronic otitis media.

Auditory Function After Application of Ototopical Vancomycin and Mupirocin Solutions in a Murine Model

Objective. To determine whether mupirocin (440 µg/mL) and vancomycin otic drops (25 mg/mL) show evidence of ototoxicity in CBA/J mice immediately following a 7-day course of daily intratympanic (IT) injections and 1 month following treatment.

Study Design. Nonrandomized controlled trial.

Setting. Academic hospital laboratory.

Subjects. Twenty CBA/J mice.

Results. Mean auditory brainstem response (ABR) thresholds increased in all drug- and saline-treated ears immediately after 7 days of IT injections but returned to baseline for most stimulus frequencies by 30 days later. This finding appeared to be correlated with the presence and subsequent resolution of tympanic membrane (TM) perforations and granulation tissue at the injection sites. Mupirocin-treated ears showed no significant difference in ABR thresholds compared to saline-treated ears. No significant differences were noted between vancomycin- and saline-treated ears, but there was a significant interaction between testing day and stimulus frequency ( P < .001). Further analysis revealed that ABR thresholds at 32 kHz remained significantly elevated in vancomycin-treated mice despite the resolution of TM perforations and granulation tissue 30 days after completion of IT injections (95% confidence interval, −13.5 to −5.5, P < .01).

Conclusion. Although IT application of mupirocin solution (440 µg/mL) caused no significant change in the ABR thresholds in a murine model, vancomycin solution (25 mg/mL) resulted in high-frequency threshold elevations in both the ear directly injected and the contralateral ear. Mupirocin solution may be beneficial in managing otitis externa and media caused by resistant pathogens. Further studies of ototopical vancomycin are needed to define parameters governing its safe use.

Ototoxic effect of topical ciclopirox as an antimycotic preparation

OBJECTIVE

To evaluate the ototoxicity of ciclopirox-containing solution as an otologic preparation for the treatment of otomycosis.

BACKGROUND

Ciclopirox is a synthetic antimycotic agent available in a variety of formulations to treat superficial fungal infections. Ciclopirox has demonstrated both fungicidal and fungistatic activity in vitro against a broad spectrum of pathogenic fungi. It also possesses a broad-spectrum antibacterial properties, anti-inflammatory, and antiedema effect. The ototoxic effect of ciclopirox-containing solutions has not been known, so the current study was designed to observe the ototoxic effect of this solution experimentally.

MATERIALS AND METHODS

Experiments were performed in 22 young male albino guinea pigs (weight, 450-550 g). The 10 animals in the experimental group received ciclopirox solution, and the control group was divided into two groups of six animals each. The first group received saline solution (negative control) and the second received gentamicin (40 mg/mL; ototoxic control). Under general anesthesia, pretreatment auditory brainstem responses (ABRs) from the right ears were obtained from the animals in all groups. The right tympanic membranes were totally perforated, and a small piece of Gelfoam was applied to the middle ear directly to the round window membrane. Ear solutions were applied through transcanal approach to the middle ear twice a day in 2 weeks. Twenty-two animals of perforated tympanic membrane were observed during a 2-week period. Posttreatment ABRs were obtained in all groups in a week after the last administration.

RESULTS

Baseline ABR results were normal in right ears of all animals tested. Animals undergoing placement of Gelfoam with either ciclopirox solution or saline in the middle ear showed no changes in the ABR threshold. The gentamicin group showed a significant change in the ABR threshold.

CONCLUSION

In the guinea pig, when applied topically to the middle ear, ciclopirox does not cause a reduction in the ABR threshold. Because its safety has not yet been confirmed in patients, caution should be observed when prescribing this agent.