[Acute external otitis]

Acute external otitis is a painful inflammation of the skin of the ear canal, usually caused by bacteria. It occurs typically in the summer time, predisposed by humidity and heat. Cleaning and corticosteroid/antibiotic drops almost always ease swelling and pain in the ear canal in a couple of days. Proper treatment also involves effective analgesic medication and advice for a correct dosing technique of ear drops. Antibiotics are necessary only if the patient is immunologically compromised or the inflammation is spreading outside the ear canal.

[How and when is topical treatment applied into the ear?]

Topical treatment is the first-line treatment for inflammation of the external auditory canal and chronic otitis media, without the need of systemic antimicrobial drug therapy. The ear canal is cleaned mechanically, by rinsing with saline, and finally dried by suction. A bacterial or fungal culture specimen should be taken, if the inflammation does not heal with the first treatment or recurs rapidly. High local drug levels without systemic adverse effects are achieved with ear drops. A combinatorial broad-spectrum antibiotic/corticosteroid ear drop is the most effective remedy for bacterial inflammation, whereas the most important therapeutic procedure in fungal infections is cleaning and topical medication.

Antibiotic resistance profiles of Staphylococcus pseudintermedius isolates from canine patients in Korea

In this study, the prevalence of antibiotic resistance was examined among 74 Staphylococcus pseudintermedius strains recently isolated from clinical cases of canine pyoderma and otitis externa at the veterinary teaching hospital at Konkuk University, Korea. Bacterial resistance to the nine commonly used antibiotics was evaluated by a standard disk diffusion technique based on the guidelines of the Clinical and Laboratory Standards Institute. The results demonstrated that most S. pseudintermedius isolates were resistant to penicillin (95.9%) or tetracycline (91.9%), but highly susceptible to amoxicillin/clavulanic acid (90.5%). Among the 74 isolates, 13 mecA-positive and methicillin-resistant S. pseudintermedius (MRSP) strains were identified, displaying a high level of resistance (84.6- 100%) to each of the individual antibiotics evaluated, with the exception of amoxicillin/clavulanic acid (46.2% resistance). Notably, all of the MRSP isolates exhibited simultaneous resistance to four or more different antibiotics, indicating that they are multiple drug resistant (MDR) strains. Taken together, these results imply that more careful selection or prescription of antibiotics for canine pyoderma and otitis externa should be required for reducing the emergence and/or spread of MDR strains, especially MDR-MRSP isolates, in veterinary pet clinics in Korea.

High prevalence of Fluoroquinolone- and Methicillin-resistant Staphylococcus pseudintermedius isolates from canine pyoderma and otitis externa in veterinary teaching hospital

Recently, a total of 74 Staphylococcus pseudintermedius isolates were collected from clinical cases of canine pyoderma and otitis externa in Korea. In this study, we examined in vitro fluoroquinolone resistance among those isolates using a standard disk diffusion technique. The results demonstrated that approximately 18.9% to 27.0% of the isolates possessed bacterial resistance to both veterinary- and human-licensed fluoroquinolones except one isolate, including moxifloxacin (18.9% resistance), levofloxacin (20.3% resistance), ofloxacin (24.3% resistance), ciprofloxacin (25.7% resistance), and enrofloxacin (27.0% resistance). Most surprisingly, 14 out of 74 (18.9%) isolates were resistant to all the five fluoroquinolones evaluated. Moreover, a PCR detection of the methicillin resistance gene (mecA) among the 74 isolates revealed that 13 out of 25 (52.0%) mecA-positive isolates, but only 7 out of 49 (14.3%) mecA-negative isolates, were resistant to one or more fluoroquinones. Taken together, our results imply that bacterial resistance to both veterinary- and human-use fluoroquinolones becomes prevalent among the S. pseudintermedius isolates from canine pyoderma and otitis externa in Korea as well as that the high prevalence of the mecA-positive S. pseudintermedius isolates carrying multiple fluoroquinolone resistance could be a potential public health problem.

Interventions for acute otitis externa

BACKGROUND

Acute otitis externa is an inflammatory condition of the ear canal, with or without infection. Symptoms include ear discomfort, itchiness, discharge and impaired hearing. It is also known as 'swimmer's ear' and can usually be treated successfully with a course of ear drops.

OBJECTIVES

To assess the effectiveness of interventions for acute otitis externa.

SEARCH STRATEGY

Our search for published and unpublished trials included the Cochrane Ear, Nose and Throat Disorders Group Trials Register; CENTRAL; PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; mRCT and additional sources. The date of the most recent search was 6 January 2009.

SELECTION CRITERIA

Randomised controlled trials evaluating ear cleaning, topical medication or systemic therapy in the treatment of acute otitis externa were eligible.We excluded complicated acute otitis externa; otitis externa secondary to otitis media or chronic suppurative otitis media; chronic otitis externa; fungal otitis externa (otomycosis); eczematous otitis externa; viral otitis externa and furunculosis.

DATA COLLECTION AND ANALYSIS

Two authors assessed eligibility and quality.

MAIN RESULTS

Nineteen randomised controlled trials with a total of 3382 participants were included. Three meta-analyses were possible. The overall quality of studies was low.Topical antimicrobials containing steroids were significantly more effective than placebo drops: OR 11 (95% CI 2.00 to 60.57; one trial).In general, no clinically meaningful differences were noted in clinical cure rates between the various topical interventions reviewed. One notable exception involved a trial of high quality which showed that acetic acid was significantly less effective when compared with antibiotic/steroid drops in terms of cure rate at two and three weeks (OR 0.29 (95% CI 0.13 to 0.62) and OR 0.25 (95% CI 0.11 to 0.58) respectively).One trial of low quality comparing quinolone with non-quinolone antibiotics did not find any difference in clinical cure rate.No trials evaluated the effectiveness of ear cleaning.Only two trials evaluated steroid-only drops. One trial of low quality suggested no significant difference between steroid and antibiotic/steroid but did not report the magnitude or precision of the result. Another trial of moderate quality comparing an oral antihistamine with topical steroid against topical steroid alone found that cure rates in both groups were high and comparable (100% (15/15) and 94% (14/15) respectively at three weeks).

AUTHORS' CONCLUSIONS

There is a paucity of high quality trials evaluating interventions for acute otitis externa. The results of this systematic review are largely based on odds ratios calculated from single trials, most of which have very broad 95% confidence intervals because of small to modest sample sizes. The findings may not be wholly generalisable to primary care for a variety of reasons; only two of the 19 trials included in the review were conducted in a primary care population setting, and in 11 of the 19 trials ear cleaning formed part of the treatment (an intervention unlikely to be available in primary care). Despite these reservations, some meaningful conclusions can be drawn from the evidence available:Topical treatments alone, as distinct from systemic ones, are effective for uncomplicated acute otitis externa. In most cases the choice of topical intervention does not appear to influence the therapeutic outcome significantly. Any observed differences in efficacy were usually minor and not consistently present at each follow-up visit. Acetic acid was effective and comparable to antibiotic/steroid at week 1. However, when treatment needed to be extended beyond this point it was less effective. In addition, patient symptoms lasted two days longer in the acetic acid group compared to antibiotic/steroid.The evidence for steroid-only drops is very limited and as yet not robust enough to allow us to reach a conclusion or provide recommendations. Further investigation is needed.Given that most topical treatments are equally effective, it would appear that in most cases the preferred choice of topical treatment may be determined by other factors, such as risk of ototoxicity, risk of contact sensitivity, risk of developing resistance, availability, cost and dosing schedule. Factors such as speed of healing and pain relief are yet to be determined for many topical treatments and may also influence this decision.Patients prescribed antibiotic/steroid drops can expect their symptoms to last for approximately six days after treatment has begun. Although patients are usually treated with topical medication for seven to 10 days it is apparent that this will undertreat some patients and overtreat others. It may be more useful when prescribing ear drops to instruct patients to use them for at least a week. If they have symptoms beyond the first week they should continue the drops until their symptoms resolve (and possibly for a few days after), for a maximum of a further seven days. Patients with persisting symptoms beyond two weeks should be considered treatment failures and alternative management initiated.

Necrotising external otitis caused by Aspergillus wentii: a case report

Necrotising external otitis (NEO) is a destructive, potentially fatal, infection usually seen in elderly diabetics or the immunocompromised. The commonest causative organism is Pseudomonas but immunocompromised patients are additionally susceptible to opportunistic infections. Here we describe the first reported case of NEO caused by a previously unknown human pathogen--Aspergillus wentii. A review of the literature reveals that fungal NEO is associated with a high rate of cranial nerve palsies suggesting that infections are not being treated rapidly enough to prevent morbidity. Fungal infection should be considered early in immunocompromised patients and microbiological diagnosis should be obtained wherever possible.

In vitro evaluation of the synergistic activity of neomycin-polymyxin B association against pathogens responsible for otitis externa

The most recent guidelines recommend, for otitis externa antibiotic therapy, the use of topical formulations in that they are very safe, have a quicker effect and do not induce bacterial resistance compared to systemic therapy. The choice of the class of antibiotics in empiric therapy of otitis externa must take into consideration the polymicrobic nature of the infection that includes both bacteria (Grampositive and Gram-negative) and mycetes. For this reason, in this study we evaluated the synergic activity of neomycin in association with polymyxin B against the pathogens commonly responsible for otitis externa, compared to that of a single antibiotic (ciprofloxacin). The polymyxinB/neomycin association shows clear synergic effects with values of both Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) reduced by 3-4 times with respect to the single antibiotic; and in P. aeruginosa the synergistic effect of the neomycin/polymyxin B association with respect to neomycin was more evident (5-6 times), with an intrinsic in vitro activity constantly higher than that of ciprofloxacin alone or in association with hydrocortisone. From the analysis of the data obtained in vitro, we can conclude that the possibility of using a topical formulation containing a synergistic association of antibiotics, such as neomycin-polymyxin B, in such a way as to obtain the maximum effect in the minimum time with an increase in the spectrum of action of non-bacterial pathogens, is an optimal choice for the clinician for the empiric therapy of otitis externa.

Benign necrotizing otitis externa

Benign necrotizing otitis externa (BNOE) is a rare condition of the external acoustic meatus characterized by ulceration of the floor of the deep meatus overlying an area of bony necrosis. Recognition of this condition as different from malignant necrotizing otitis externa (MNOE) and carcinoma of the external ear is important because its treatment is very different. The best choice of treatment for BNOE is not clear because both long-term medical therapy and surgery have been advocated as first-line treatments. We describe a case involving a 50-year-old man and present what we believe to be the first published photographs of the surgical management of BNOE.

Acute otitis externa: management by GPs in North Queensland

BACKGROUND

Acute otitis externa (AOE) is a common condition in North Queensland. Clinical guidelines exist for the management of this condition. This study explores the pattern of causative pathogens and management of AOE by general practitioners in North Queensland.

METHODS

Eight general practices in three regional cities of North Queensland participated in the study. The three components were: a retrospective case audit of AOE management, a survey of GPs' self reported usual management, and collection of clinical data and microbiological specimens from new cases.

RESULTS

Pseudomonas aeruginosa was the most common causative pathogen in all regions, GPs correctly identified the most common pathogens, there was variation in the use of oral antibiotics between regions (15.8-36.6%), ear syringing is commonly used in managing AOE (51.3%), and most patients (68.9%) required only one GP appointment.

DISCUSSION

General practitioners have good knowledge of the causative pathogens for AOE in their region. While clinical guidelines are generally followed, there is some variation in the prescription of oral antibiotics and use of ear syringing in managing this condition.

Differences in bacteriologic treatment failures in acute otitis externa between ciprofloxacin/dexamethasone and neomycin/polymyxin B/hydrocortisone: results of a combined analysis

OBJECTIVE

To compare treatment failure rates for the two major acute otitis externa (AOE) pathogens, Pseudomonas aeruginosa and Staphylococcus aureus, by topical therapy with ciprofloxacin 0.3%/dexamethasone 0.1% (CDex) or neomycin 0.35%/polymyxin B 10,000 IU/mL/hydrocortisone 1% (Cort) based on clinical and microbiological failure in patients positive for these pathogens at baseline.

RESEARCH DESIGN AND METHODS

A combined analysis was conducted from two similar, but non-identical clinical trials involving CDex vs. Cort. Outcomes of the combined efficacy analysis were treatment failure rates and antibiotic susceptibility values for P. aeruginosa and S. aureus. The raw data for the treatment failure rates from the two studies were combined to calculate the overall treatment failure rates of each treatment group. Chi-square tests of independence were conducted to assess differences in treatment failure rates between treatment groups.

RESULTS

Of the 789 patients with culture-positive ears prior to the initiation of therapy, 61.0% (n = 481) were positive for P. aeruginosa and 8.9% (n = 70) were positive for S. aureus. While treatment failure rates for S. aureus were similar for the two therapies, CDex had a significantly lower treatment failure rate than Cort (5.1 vs. 13.0%; p = 0.0044) for P. aeruginosa. All of the persisting P. aeruginosa and S. aureus isolates were susceptible to fluoroquinolones and neomycin/polymyxin B.

LIMITATIONS

The analysis strength is dependent on pooled data from similar studies.

CONCLUSIONS

Ototopical ciprofloxacin 0.3%/dexamethasone 0.1% more effectively eradicates P. aeruginosa compared to Cort. Eradication of S. aureus by either drug was similar. These results favor CDex as a better first-line choice in the treatment of AOE compared to Cort.

Protease activities of Candida spp. isolated from otitis externa: preliminary result

Otomycosis is a fungal infection of the ear predominantly caused by Candida and Aspergillus spp. The possible virulence factors of Candida spp. are enzymes, such as proteases, phospholipases, phosphatases and esterase. According to our knowledge, protease production in Candida strains isolated from patients with otomycosis has not been investigated. The present study was aimed at determining in vitro protease activity in 8 strains of Candida spp. (C. parapsilosis, C. famata, C. guilliermondii and C. albicans) isolated from children with otomycosis. A majority of isolated strains 7/8 (87.5%) were protease positive. The protease activity ranged from Pz 0.61 to 0.78. Further investigation is necessary to clarify the contribution of protease production to Candida virulence associated with otomycosis.

[Generalized tetanus with otitic portal of entry after using intra-auricular traditional remedies in a 2 old child]

A case of tetanus with uncommon way of contamination was found in the paediatric department of the Yopougon teaching hospital in Côte d'Ivoire. A two-year-old child, without vaccination against tetanus and suffering from a chronic otitis presented a generalized tetanus, after the use of traditional local remedies in his ear. Through this observation, the authors want to make population aware of the detrimental effects of traditional local auricular remedies and want to advise all physicians to make a serotherapy and/or a vaccination against tetanus to all children with chronic otitis in our area.

Comparative study of the microbial profile from bilateral canine otitis externa

Fifty dogs with bilateral otitis externa were studied over a 10-month period. The exudates of both external ears were obtained, using sterile swabs, and microorganisms were isolated according to standard microbiological techniques. Antimicrobial susceptibility testing of Staphylococcus intermedius was done by the agar diffusion method. There was bacterial and/or fungal growth in all of the samples. These were all polymicrobial infections. Anaerobic bacteria were not isolated in any sample. The most common pathogens isolated were S. intermedius and Malassezia pachydermatis. A statistically significant difference (P < 0.05) was observed in the isolation pattern between the right and left ears in 34 of the 50 animals (68%). High resistance rates of S. intermedius strains to penicillin, ampicillin, erythromycin, tetracycline, and clindamycin were found. The results suggest that in bilateral canine otitis externa, each ear should be cultured separately and considered as separate units.

Management of Malassezia-related diseases in the dog

Most cases of Malassezia dermatitis/otitis in the dog are associated with concurrent dermatoses or systemic diseases and recurrences are not uncommon. Recognition and control of the predisposing factors are therefore key factors for successful therapy and prevention of recurrent infections. Currently, Malassezia dermatitis/otitis is managed by the use of antifungal drugs. Systemic therapy is often necessary, in particular when clinical signs are severe and widespread. Ketoconazole and Itraconazole are the most commonly used drugs. Topical therapy is an alternative in case of localized lesions and external ear localizations. Different commercial formulations, available in clinical practice in form of creams, gels, lotions, sprays and ear drops are often used as adiuvants to systemic therapy. Topicals more frequently used are represented by imidazolic antifungals, chlorhexydine and lime sulphur. The presentation deals with more recent advances about the protocols for treatment of Malassezia-related diseases in the dog. New perspectives, as the use of natural compounds, immunotherapy and inhibitors of yeast adherence factors, are also discussed.

Diagnostic and clinical features of animal malasseziosis

Malassezia yeasts infection represents a common clinical concern with a special regard to canine dermatology. The Authors review the main clinical features of malasseziosis in canine and feline medicine, summarizing predisposing factors and aetiopathogenesis of the yeasts' infection. A special reference was given to clinical and microscopical diagnosis.

Fungal malignant otitis externa treated with hyperbaric oxygen

OBJECTIVE

To report a case of Aspergillus flavus malignant otitis externa, successfully treated with antifungal agents, surgical debridement, and hyperbaric oxygen treatment.

PATIENT

The case was a 77-year-old man with non-insulin dependent diabetes mellitus, who presented with otalgia and purulent otorrhea. Intervention was with surgical debridement, antifungal agents, and hyperbaric oxygen treatment. The main outcome measures were radiological and histological findings.

CONCLUSIONS

A. flavus is a rare cause of malignant otitis externa. Aggressive treatment should include surgical debridement, with appropriate antifungal agents and hyperbaric oxygen therapy.

Otitis externa: the analysis of relationship between particular signs/symptoms and species and genera of identified microorganisms

OBJECTIVE

To investigate a relationship between the etiological factor of external otitis and occurrence of particular signs/symptoms.

DESIGN

A special questionnaire was designed and completed by all patients covering personal details, medical history, results of otolaryngological examination and bacteriological and mycological investigations.

SUBJECTS

249 patients of the Outpatient Department of Laryngology at the Regional Hospital in Bełchatów with symptoms of external otitis. For analysis of relationships between particular signs/symptoms and species/genera of microorganisms, statistical tests were used: chi2 test, chi2 test with Yate's modification, C-Pearson index, and Fisher exact test for very small samples.

RESULTS

There is a statistical dependence between discharge, hearing loss, swelling of skin, scant, dried discharge with fetid odour and bacteria isolated from the external ear canal. Similar dependence exists between pain, hearing loss, no smelly discharge or wet, black plug of fetid odour and fungi. Also there is a statistical dependence between pruritus, red skin and grey, fetid discharge and mixed flora.

CONCLUSIONS

Some of symptoms and signs are connected with definite etiological factors which is important not only for correct diagnosis but also for institution of appropriate and effective treatment. On the basis of some characteristic symptoms and signs it is possible to make a tentative diagnosis as to the etiological pathogen responsible for external otitis.

High occurrence of multi-antimicrobial resistance in Staphylococcus intermedius isolates from healthy and diseased dogs and domesticated pigeons

Staphylococcus intermedius isolates (n=106), including 44 dog isolates and 62 pigeon isolates, were examined for their susceptibility to ampicillin, cephalexin, erythromycin, gentamicin, kanamycin, lincomycin, norfloxacin, oxacillin, tetracycline, and vancomycin by standard disk-diffusion test. The frequencies of resistance to ampicillin, kanamycin, and tetracycline were significantly higher in dog isolates than pigeon isolates (95.5% vs. 0%, 31.8% vs. 0%, and 45.5% vs. 9.7%, respectively; P<0.01). Antimicrobial resistance patterns of dog isolates and pigeon isolates were categorized respectively into nine and five distinct profiles. Significantly higher occurrence of resistance to two or more antimicrobials was observed in dog isolates than pigeon isolates (54.5% vs. 12.9%; P<0.01) and also in domesticated pigeon isolates than non-domesticated pigeon isolates (53.3% vs. 0%; P<0.01).

Necrotizing external otitis: a report of 46 cases

OBJECTIVES

To define germs involved, clinical presentation, treatment regimen, and prognostic factors in necrotizing external otitis.

PATIENTS AND METHODS

Retrospective study reviewing a series of 46 patients treated during 10 years in a tertiary care center. Diagnosis was confirmed by using otomicroscopy, computed tomographic and/or magnetic resonance imaging scan and bone scintigraphy (Te 99 and Ga 26 bone scan). Patients were provided ceftazidime and ciprofloxacin intravenously and monitored using a Ga-67 bone scan. The following were assessed: presenting symptoms, general context, bacteriological analysis, imaging protocol sensitivity, complications, delay to healing, and cure rate.

RESULTS

Sex ratio was 2.29 (mean age, 73.6 yr). The most common presenting symptoms were otalgia and otorrhea in 97.8 and 91.3%, respectively. Facial paralysis was present in 19.6% of cases. Thirty patients had diabetes mellitus (65.2%), and 8 were immunocompromised (17.4%). Pseudomonas aeruginosa was isolated in 69.2% of cases and was resistant to ciprofloxacin in 18.5%, but was susceptible to ceftazidime in all cases. Four patients died during the treatment (4.4%), but only 2 of disease. The mean delay to healing was 14 weeks (SD, 9.7). Healing rate was 95.6%. No relapse was observed after a mean follow-up of 78.4 weeks (SD, 36.5 wks). Two factors significantly influenced the prognosis: facial paralysis and existence of systemic factors for immune deficiency (p = 0.023 and 0.038, respectively).

CONCLUSION

The association of ciprofloxacin and ceftazidime was efficient in countering the increasing resistance of P. aeruginosa to quinolones. We propose a prognostic classification of necrotizing external otitis based on the presence of facial paralysis and/or systemic factors.