Optimum incubation conditions for the isolation of yeasts from canine otitis externa

Samples from otitis externa in the dog were cultured on a variety of media under different conditions of incubation in order to assess the most suitable conditions, especially for the isolation of Malassezia pachydermatis. Columbia blood and MacConkey agar at 37 degrees C for 24 h with air and Sabouraud glucose agar under microaerophilic conditions for 48 h at 37 degrees C were considered the ideal combination.

Otitis externa in a localized area at the South of Jordan

OBJECTIVE

To investigate the clinical findings and to identify the microorganisms in the pathogenesis of otitis externa.

METHODS

The symptoms and signs, as well as the bacterial flora, from the auditory canals of 70 Jordanian patients (94 ears) suffering from otitis externa were studied during the period from February 1999 to February 2000.

RESULTS

Pain was the most common symptom (82%). The most common sign was erythema (65%), while oedema was the least common (42%). Pseudomonas aeruginosa was found in 39%, Aspergillus in 27%, Candida albicans in 18%, Staphylococcus aureus in 18% and no growth in 8.5%. Ninety three percent of healthy ears revealed normal skin flora.

CONCLUSION

Gram-negative microorganisms (Pseudomonas aeruginosa) were the most frequently isolated pathogenic microorganisms.

Fatal invasive cerebral Absidia corymbifera infection following bone marrow transplantation

A 56-year-old dairy farmer received a fully HLA matched unrelated donor marrow transplant for high risk CML in chronic phase. His early post-transplant course was complicated by a series of massive intracerebral bleeds and by sepsis related to a malignant otitis externa. The microbial pathogen isolated from ear swabs was found to be Absidia corymbifera, but CT scan at the time showed no intracerebral extension. Despite neutrophil engraftment and aggressive antifungal management he succumbed. Autopsy revealed invasion of Absidia into the brain from the ear. We speculate that colonisation by Absidia resulted from occupational exposure.

Antimicrobial susceptibility of staphylococci isolated from otitis externa in dogs

Samples were obtained from 65 unmedicated adult dogs, processed for isolation of Staphylococcus species and tested for susceptibility to penicillin G, gentamicin, oxacillin, tetracycline, trimethoprim-sulphamethoxazole, streptomycin, ampicillin and rifampin. Forty-four isolates were obtained, which represents 67.7% of samples. Coagulase-negative species were most commonly found, and the most frequently isolated staphylococcus species were Staph. epidermidis and Staph. aureus. Other species, such as Staph. simulans, Staph. haemolyticus, Staph. saprophyticus and Staph. intermedius were also isolated. Resistance to antibiotics was frequently observed, with 90.9% of the isolates showing resistance to at least one drug. The most active antimicrobial agents against staphylococci isolated from otitis externa of dogs were rifampin and oxacillin. Multidrug resistance was a common finding, and one strain of Staph. haemolyticus species, was resistant to all tested antimicrobial agents. Resistance to three or more different drugs was a common finding, observed in 16 strains (36.4%) of both coagulase-positive and coagulase-negative staphylococci. This study highlights the emergence of cases of otitis externa determined by coagulase-negative staphylococcus strains and once more emphasizes the need for bacterial culture with species identification and susceptibility testing of swab specimens from the ear canal in order to choose appropriate antimicrobial agents.

An unusual source of Vibrio alginolyticus-associated otitis: prolonged colonization or freshwater exposure?

Otitis externa and otitis media are commonly encountered in clinical practice. We report an unusual case of otitis externa, which was caused by Vibrio alginolyticus, several months after saltwater exposure. Clinicians need to be aware of this unusual pathogen, especially in refractory cases of ear infections.

Atypical lipid-dependent Malassezia species isolated from dogs with otitis externa

During a survey of the occurrence of Malassezia species in the external ear canals of dogs with chronic otitis externa, lipid-dependent Malassezia species were isolated in three dogs. These species were identified as Malassezia furfur and M. obtusa but showed atypical assimilation patterns. To our knowledge, this is the first report of the isolation of lipid-dependent species of the genus Malassezia in association with canine otitis.

Non-pseudomonal malignant otitis externa and jugular foramen syndrome secondary to cyclosporin-induced hypertrichosis in a diabetic renal transplant patient

We present the case of a 58-year-old diabetic renal transplant patient who developed a left jugular foramen syndrome, secondary to an ipsilateral staphylococcal malignant (necrotizing) otitis externa. This followed a protracted episode of uncomplicated otitis externa with no evidence of bone involvement on computed tomography (CT) scanning. Cyclosporin-induced hypertrichosis (excess hair growth) in his external auditory canal contributed greatly to the initial difficulty in managing his otitis externa. Following an initial successful treatment with prolonged intravenous antibiotics the patient relapsed with a secondary infection in the same anatomical site due to Candida parapsilosis. Despite further intensive treatment including antimicrobials, a subtotal petrosectomy and hyperbaric oxygen therapy he eventually succumbed to his disease.

Antibacterial susceptibility patterns of Pseudomonas strains isolated from chronic canine otitis externa

Development of antibiotic resistance in bacteria is a problem of great concern. It is important to establish the convenience of antimicrobial susceptibility tests in animal infections. The aim of this study was to test the susceptibility to antibiotics of Pseudomonas strains isolated from chronic canine otitis externa. We tested 23 strains of Pseudomonas: 19 Ps. aeruginosa, three Ps. fluorescens and one Pseudomonas spp. The most effective antibiotics were tobramycin (100% susceptible), marbofloxacin (91.3%) and ceftazidime (91.3%). Ticarcillin and gentamicin, commonly used for the treatment of otitis externa also showed good results (susceptibility of strains was 86 and 65.2% respectively). Lower susceptibility was found using enrofloxacin (52.1%) probably due to its indiscriminate use. We emphasize the need for a rational policy of antibiotic prescribing in order to prevent the selection of resistant strains.

Molecular phylogenetic evidence for noninvasive zoonotic transmission of Staphylococcus intermedius from a canine pet to a human

rRNA-based molecular phylogenetic techniques were used to identify the bacterial species present in the ear fluid from a female patient with otitis externa. We report the identification of Staphylococcus intermedius from the patient and a possible route of transmission. Analysis of 16S ribosomal DNA restriction fragment length polymorphisms indicated that the dominant species present was S. intermedius. A pet dog owned by the patient also was tested and found to harbor S. intermedius. In humans, the disease is rare and considered a zoonosis. Previously, S. intermedius has been associated with dog bite wounds, catheter-related injuries, and surgery. This study represents the first reported case of a noninvasive infection with S. intermedius.

Otitis externa associated with Malassezia sympodialis in two cats

The lipid-dependent species Malassezia sympodialis was isolated from two cats with otitis externa. To our knowledge, this is the first report of the isolation of lipid-dependent species of the genus Malassezia associated with skin disease in domestic animals.

A study of tea tree oil ototoxicity

Tea tree oil shows promise as an effective treatment for a number of micro-organisms commonly associated with otitis externa and otitis media, but its possible ototoxicity has not been previously assessed. The ototoxicity of tea tree oil was examined in the guinea pig by measuring the thresholds of the compound auditory nerve action potential (CAP) to tone bursts before and after instillation of the oil into the middle ear. After 30 min of instillation, 100% tea tree oil caused a partial CAP threshold elevation at 20 kHz. A lower concentration of oil [2% tea tree oil dissolved in saline using 0.5% detergent (Tween-80)] did not cause any significant lasting threshold change after middle ear instillation for the same period of time. The latter concentration of oil is greater than the minimum inhibitory concentration reported for most micro-organisms in the effective spectrum of the oil and this suggests that this concentration may be safe and effective provided only short exposures (about 30 min) are used. The results suggest that high concentrations of tea tree oil applied to the round window for a relatively short time are to some extent ototoxic to the high-frequency region of the cochlea. Hence further study is needed to establish whether tea tree oil can be used with safety in the treatment of external and middle ear infections.

Evaluation of in vitro activity of two topical products against three organisms isolated from canine referral patients with otitis externa and cutaneous pyoderma

Canine otitis externa and cutaneous pyoderma are common problems that are often associated with Staphylococcus intermedius, Pseudomonas aeruginosa, and Malassezia pachydermatis. In vitro activity of two topical products against these organisms isolated from canine referral patients were evaluated. Organisms were grown and diluted to a concentration equivalent to 10(7) colony-forming units (CFU) per mL and exposed to either a 0 or 1/5 dilution of Hexadene Flush with Spherulites (Virbac Animal Health Inc, Fort Worth, TX) or a 1/5 or 1/25 dilution of ResiCHLOR Lotion with Spherulites (Virbac Animal Health Inc, Fort Worth, TX) at time intervals from 1 to 30 minutes. Results showed that all three organisms were killed within 1 minute of contact time at 0 and 1/5 dilution of the flush. The lotion diluted to 1/5 also killed all three organisms. At 1/25 dilution, this lotion killed S. intermedius and P. aeruginosa within 1 minute of contact time, whereas M. pachydermatis was killed after 1 minute. The findings suggest that the two topical products exhibit efficacy against these common skin pathogens in vitro and can be useful in their clinical management.

Malignant otitis externa caused by Malassezia sympodialis

BACKGROUND

Malignant otitis externa caused by fungal infections is rare. A review of the literature showed only 9 cases, and the causative fungus in all cases was Aspergillus. This article reports an unusual case caused by Malassezia sympodialis.

METHODS

A 53-year-old man with non-insulin dependent diabetes presented with malignant otitis externa. He deteriorated despite treatment with intravenous antipseudomonal therapy and surgical debridement. Microbiologic tests revealed M. sympodialis. He responded rapidly to intravenous amphotericin.

RESULTS

Systemic human infections caused by M. sympodialis have not been reported. M. furfur systemic infection is rare and has been associated lipid hyperalimentation by means of a central catheter. Only 1 other case of M. fungemia without these associated risk factors has been reported.

CONCLUSIONS

The first case of malignant otitis externa caused by M. sympodialis is presented. It highlights the difficulty of initial biologic diagnosis and the need for lipid-enriched media to grow this fastidious organism.

Necrotizing otitis externa caused by Staphylococcus epidermidis

We present a case of malignant necrotizing otitis externa (MNOE) caused by Staphylococcus epidermidis, which is usually a non-pathogenic microorganism. The patient is an otherwise healthy, nondiabetic 58-year-old white man. Contributory history began in 1994 after surgery for bilateral exostoses of the external auditory canals. Between April 1994 and May 1998 persistent otalgia occurred, with progressive mixed hearing losses, purulent discharge from both ears, spontaneous perforations of the tympanic membranes and ulceration of canal wall skin. From the beginning, Staph. epidermidis was isolated in all but one culture, but was not recognized as the pathological agent because of the presence of other more frequently involved bacteria and fungi. After multiple intravenous and oral antibiotics and antifungal treatments failed, further management involved frequent debridement of both external auditory canals and tympanic membranes, right tympanoplasty, bilateral mastoidectomy, revision tympanomastoidectomies and left modified radical mastoidectomy. Antistaphylococcal therapy including ceftazidime, vancomycin, teicoplanin, clindamycin and rifampicin was tried. Following the modified radical radical mastoidectomy, normalization of the status of his ears took approximately 2 months and has since remained stable to date. His left ear is deaf because of vancomycin administration, while magnetic resonance imaging and gallium scintigraphy have shown persistent inflammation of the skull base.

Treatment of otitis externa in children

Inflammation of the external auditory canal can be localised or diffuse, and acute or chronic. Predisposing conditions include external trauma, loss of the canal's protective coating, maceration of the skin from water or humidity, and glandular obstruction. Acute otitis externa is generally caused by Pseudomonas aeruginosa or Staphylococcus aureus. Management of patients with otitis externa includes debridement, topical therapy with acidifying and antimicrobial agents, and systemic antimicrobial therapy when indicated. The management of patients with chronic otitis externa includes cleansing and debridement accompanied by topical acidifying and drying agents. This is followed by topical antibiotics and corticosteroid preparations. Surgery is mainly used to allow cleansing and aeration and/or removal of the scarred tissue. Patients with acute localised otitis externa (furunculosis) are treated with local heat and systemic antibiotics in the inflammatory stage, and drainage in the abscess state. Mycotic external otitis is managed with topical acidifying and antifungal agents, while viral (herpes) infection is treated with topical and systemic aciclovir (acyclovir). Patients with necrotising (malignant) external otitis, which is mainly caused by P. aeruginosa and S. aureus, are treated with systemic antibiotics and, rarely, by surgical debridement. Therapy for eczematous otitis externa is first directed at the secondary infection, and thereafter at the primary dermatological condition. Prevention of recurrent external otitis is aimed at minimising ear canal trauma and the avoidance of exposure to water. Preventative use of topical acidifying agents or 70% alcohol is also advocated.

Prevalence of Malassezia spp. in the ears of asymptomatic cattle and cattle with otitis in Brazil

Yeasts of the genus Malassezia are lipophilic microorganisms that are saprophytes that can act as opportunistic pathogens in animals. Malassezia pachydermatis is commonly isolated from the ear canal and skin of healthy dogs, or in association with seborrheic dermatitis and otitis externa conditions. The objective of the present study was to determine the occurrence of Malassezia spp. in the ears of healthy bovines and bovines with otitis. Specimens (secretion or cerumen) were collected with sterile swabs, inoculated onto Mycosel medium, supplemented with olive oil, and incubated at 35 degrees C for 1 week. Yeasts were identified according to morphological characteristics, growth in Dixon medium at 32 degrees C and Sabouraud glucose medium modified by the addition of Tween 20, 40 or 80. The results showed that 54.7% of the cultures were positive in bovines with otitis (75) and 34.6% were positive in healthy bovines (378). Analysis of the positive cultures (41) from animals with otitis allowed presumptive identification of 24 strains corresponding to M. globosa (12), M. slooffiae (5), M. furfur (5) and M. sympodialis (2). Further studies on a larger number of animals may confirm the trend verified thus far, i.e. a higher frequency of isolation of Malassezia spp. from animals with otitis than from healthy animals (P<0.01) and a predominance of the species M. globosa.

Wound contamination and antimicrobial susceptibility of bacteria cultured during total ear canal ablation and lateral bulla osteotomy in dogs

OBJECTIVE

To detect contamination of wound sites from surgical handling of excised tissues during total ear canal ablation and lateral bulla osteotomy in dogs, and to compare susceptibility of bacterial isolates to cefazolin with susceptibility to other antimicrobial agents.

DESIGN

Prospective clinical study.

ANIMALS

13 dogs.

PROCEDURE

Dogs were treated surgically for otitis externa and media via total ear canal ablation and lateral bulla osteotomy. Specimens for aerobic bacterial culture were obtained from SC tissue immediately following skin incision, tissues excised from the osseous bulla (after transection of the horizontal ear canal and lateral bulla osteotomy), and from SC tissue prior to skin closure. Antimicrobial susceptibility of bacterial isolates to various antibiotics was determined by use of a broth dilution assay.

RESULTS

There was a significant association between isolation of Streptococcus canis and Escherichia coli from specimens from the osseous bulla and specimens from the SC tissues prior to skin closure, indicating contamination of the SC tissues during surgery. Seventy percent of bacterial isolates were susceptible to cefazolin.

CLINICAL IMPLICATIONS

Measures to limit bacterial contamination resulting from tissue handling during total ear canal ablation and lateral bulla osteotomy are necessary. Bacteriologic culture of tissue of the osseous bulla and determination of antimicrobial susceptibility are recommended. Administration of cefazolin alone may not be efficacious for antimicrobial prophylaxis.

Treatment patterns for otitis externa

BACKGROUND

Although otitis externa is a common and painful infection of the outer ear canal, there is little specific information available regarding current treatment patterns in the United States. We wanted to examine treatment patterns for otitis externa.

METHODS

Data were analyzed from the 1993 National Ambulatory Medical Care Survey (NAMCS) and the 1993 National Hospital Ambulatory Medical Care Survey (NHAMCS) for adults and children treated for otitis externa. Data analyses included the reasons for physician visits, concomitant diagnoses, types of physicians seen, sources of payment, medical procedures administered, drugs prescribed, and patient disposition following a physician visit.

RESULTS

Study results suggested that treatment patterns differ substantially for adults and children, as well as by physician specialty. Although otitis externa is frequently painful, few cases are classified as severe, and the data indicated that less than 20 percent of patients have concomitant diagnoses treatable by medication. Nevertheless, 40 percent of patients received both topical and systemic medication, and many of the oral antibiotics prescribed are not active against Staphylococcus aureus or Pseudomonas aeruginosa, the most common bacterial pathogens in otitis externa.

CONCLUSIONS

Appropriate treatment of localized otitis externa with topical antibiotics should eliminate the need for systemic medications. Addition of systemic medications can unnecessarily increase treatment costs and the likelihood of side effects, and could reduce the likelihood of patient compliance.

Susceptibility of bacterial isolates from chronic canine otitis externa to twenty antibiotics

In this paper we present the results of studies on the susceptibility to antibiotics of bacteria isolated from chronic canine otitis externa. We tested 46 bacterial strains (S. aureus, coagulase-negative staphylococci, Corynebacterium spp., and gram-negative bacilli) with 20 different antibiotics. We observed increased resistance to antibiotics of bacteria isolated from canine otitis externa as compared to the resistance reported earlier. This may be due to the indiscriminate use of some antibiotics in the last years and indicates the importance of sensitivity testing for the effective treatment of chronic otitis externa, especially that caused by gram-negative bacilli. The clinician may initiate empiric treatment with antibiotics before obtaining the sensitivity test results; the best results may be expected from a topical application of Bacitracin or Chloramphenicol, and from a systemic therapy with Cephalosporines. Therapeutical scheme for treating various bacterial groups are presented in the paper.

[Antimicrobial activity of ofloxacin against recent clinical isolates from otitis media and otitis externa]

In order to evaluate the annual changes of susceptibility, minimum inhibitory concentrations (MICs) of ofloxacin (OFLX) and 4 control drugs were determined against clinical isolates that were obtained from patients with otitis media and otitis externa during the periods between January and December 1993, and the periods between October 1996 and March 1997. The results are summarized as follows: 1. No annual changes were seen for MIC50 of OFLX, but MIC80 and MIC90 of that rose against methicillin-resistant Staphylococcus aureus (MRSA), coagulase-negative staphylococci (CNS) and Pseudomonas aeruginosa from 1993 to 1996. It appears that resistance to OFLX is increasing among these bacteria. Detection frequency of highly resistant strains to OFLX (MIC > 100 micrograms/ml) was lower than to other control drugs. 2. No annual changes were seen of MIC50, MIC80 and MIC90 of OFLX against methicillin-susceptible S. aureus (MSSA), Streptococcus spp., Proteus spp. and Haemophilus influenzae. OFLX showed strong antimicrobial activities against these bacteria. 3. Since there was no large annual changes in the antimicrobial activity of OFLX against clinical isolates that were obtained from patients with otitis media and otitis externa, OFLX otic solution was considered as one of the clinically useful drugs even now.

Prevalence of otomycosis in malnourished children in Edo State, Nigeria

Out of the total number at 200 suspected cases of otomycoses consisting of 40 malnourished and 160 apparently healthy children examined in this study between the months of July and August in Edo State, 64 Cases (32%) were identified to be of fungal aetiology on the basis of positive culture and careful microscopic examination. The state at protein energy malnourishment was deterwined using physicians' comments in their case files. The fungal agents isolated were Aspergillus niger 28 (43.8%); A. fumigatus 4 (25%); Fusarium solari 4 (6.3%); Candida albicans 8 (12.5%); and Hendersonula teruloidea types torn B 5 (6.3%). Of these isolates, A. niger having an solation rate of (43.8%) was found to be the most predominant fungal species associated with otomycosis.

Identification of infectious Pseudomonas aeruginosa strains in an occupational saturation diving environment

OBJECTIVES

Occupational saturation divers have various skin disorders, of which skin infections are the most serious and frequent. Pseudomonas aeruginosa is the microbe most often isolated from skin infections in divers. The purpose of the present work was (a) to report the occurrence of P aeruginosa in skin infections in operational saturation diving in the North Sea from 1987 to 1995; (b) to report the environmental occurrence of P aeruginosa in saturation diving systems, and finally (c) to identify possible relations between infection related to strains of P aeruginosa and environmental isolates of the microbe.

RESULTS

During the period 1987-95, P aeruginosa was isolated from 257 skin infections in operational saturation divers. Most of the isolates related to infection by P aeruginosa show a unique growth inhibition pattern towards the normal skin flora, and the serotype pattern of P aeruginosa from skin infections is limited compared with similar infections in non-divers. In a mini-epidemiological study on board one diving vessel during one operational diving period, five significantly different DNA fragment profiles were found among the 12 isolates related to infection by P aeruginosa obtained from the saturation system. In two cases the infectious genotypes were detected in the fresh water for the saturation chambers weeks before the arrival of the infected diver.

CONCLUSIONS

The most commonly used epidemiological marker for P aeruginosa world wide, also used in earlier studies, is serotyping, but with pulsed field gel electrophoresis (PFGE) miniepidemiology it was shown to be insufficient for epidemiological purposes in saturation environments. PFGE analyses were shown to be superior both to antibacterial factor and to serotyping in epidemiological analyses of P aeruginosa infections in saturation diving.

Otitis externa malignant. A case report and review of literature

Otitis externa malignant (OEM) is a virulent infection if it is not diagnosed and treated promptly. Its mortality rate was reported to be 53% when there is associated facial nerve paralysis. It usually affects elderly diabetic patients, who present with deep-seated pain and other features of non-resolving otitis externa. It is mostly caused by Pseudomonas (P) aeruginosa and the treatment of choice is anti-Pseudomonas antibiotic. A 64-year-old diabetic male patient is described who presented with left ear pain and discharge for two months and did not respond to ordinary treatment. The patient also noticed a progressive facial weakness on the same side. The clinical presentation, investigations, treatment and follow-up of the OEM are discussed on the basis of our case and the review of the literature. The diagnosis of OEM is based on high index of suspicion and confirmed by histopathologic changes and radionuclide studies. Gallium 67 citrate scan is a sensitive way to diagnose and follow up the regression of the disease in response to the medical treatment. Ciprofloxacin is the treatment of choice; however, it has to be in accordance to culture and sensitivity results.

Yolk sac tumor of the ear in a child

OBJECTIVE

This study aimed to describe the clinical, histopathologic, and immunohistochemical findings of the second case of an endodermal sinus tumor of the ear.

STUDY DESIGN

This clinical study is a retrospective case report combined with a literature review.

SETTING

The patient was treated at the University Erasmus Hospital.

INTERVENTION

Diagnosis was confirmed by computed tomographic scan and histologic analysis. The treatment was surgical.

RESULTS

The patient underwent surgical treatment, and a locoregional relapse developed. The clinical evolution was in accordance with previous reports of extragonadal endodermal sinus tumor sites. The family refused chemotherapy, and the patient died 3 months after admission.

CONCLUSIONS

An endodermal sinus tumor is a malignant germ cell tumor that usually involves the gonadal tissue. Extragonadal sites are rare, and different hypotheses have been evoked to explain these locations. Treatment options include surgical removal and chemotherapy. This is the second case of an endodermal sinus tumor of the ear.

ENT manifestations of Pseudomonas aeruginosa infection in HIV and AIDS

In acquired immunodeficiency syndrome (AIDS), opportunistic infections occur which are usually related to defects in cell-mediated immunity. However, there has also been an increase in the incidence of bacterial infections in this population, including infections caused by Pseudomonas species. This study reveals the wide range of ear, nose and throat manifestations which can be caused by Pseudomonas aeruginosa in patients with HIV and AIDS and illustrates the need for a high index of clinical suspicion combined with accurate microbiological data for treating these potentially life-threatening infections. In addition, treatment using combination chemotherapy, such as ciprofloxacin and ceftazidime, is advised, as it has been shown that dual therapy results in a significantly lower mortality.

Otitis externa--the clinical pattern in a tertiary institution in Singapore

Otitis externa is a common condition in the tropics. Most of the data related to the condition have arisen from Western sources. Locally, the aetiology and the pathogens identified have not been systematically studied. A prospective study involving 107 patients was conducted. Otomycosis was frequently encountered. Coagulase negative Staphylococcus and Aspergillus niger were the most common bacteria and fungus cultured respectively. Gentamicin and polymyxin B were the most effective topical agents against Pseudomonas aeruginosa. Self-cleaning of the ears was the most common predisposing factor.

Malignant otitis externa with optic neuritis

Malignant otitis externa is a serious condition that presents difficulties in treatment, and also in monitoring its progress. A case of malignant otitis externa with optic neuritis is presented that remained refractory to standard treatment but was cured by adjuvant hyperbaric oxygen therapy. This is the only reported case that has survived this disease with optic neuritis. The usefulness of imaging techniques in this condition is discussed, as well as the ESR, in evaluating the effectiveness of treatment.

Necrotizing external otitis caused by Aspergillus fumigatus: computed tomography and high resolution magnetic resonance imaging in an AIDS patient

Most necrotizing (malignant) external otitis (NEO) occurs in diabetic patients and is commonly caused by Pseudomonas aeruginosa. We report an acquired immunodeficiency syndrome (AIDS) patient with NEO caused by Aspergillus fumigatus in which computed tomography (CT) showed destructive petrous bone involvement and magnetic resonance imaging (MRI) of the ear discovered extensive soft tissue and facial nerve involvement. Dedicated MRI studies of the ear in this type of pathology provide new insights relating to nerve dysfunction, that cannot be obtained with CT.

Ofloxacin otic solution for treatment of otitis externa in children and adults

OBJECTIVE

To compare the safety and efficacy of ofloxacin otic solution with those of Cortisporin otic solutions (neomycin sulfate, polymyxin B sulfate, and hydrocortisone) in otitis externa in adults and children.

DESIGN

Two randomized, evaluator-blind, multicenter trials, 1 each in children and adults.

SETTING

Twenty-three primary care and referral ambulatory care sites per trial.

PATIENTS

A total of 314 adults (12 years and older) and 287 children (younger than 12 years). Of the total, data for 247 adults and 227 children were considered clinically evaluable (CE), and those for 98 children and 98 adults were microbiologically evaluable (ME).

INTERVENTIONS

Ofloxacin (adults, 0.5 mL; children, 0.25 mL) twice daily or Cortisporin (adults, 0.2 mL; children, 0.15 mL) 4 times daily for 10 days.

MAIN OUTCOME MEASURES

The CE subjects were cured if all signs and symptoms resolved at posttherapy (days 11-13) and test-of-cure (days 17-20) visits. The ME subjects had microbiological and clinical successes if they were cured and had microbiological eradication or presumed eradication.

RESULTS

Cure was observed in 82% and 97% of CE adults and children treated with ofloxacin and 84% and 95% of CE adults and children treated with Cortisporin, respectively. The most common pathogens at the pretherapy visit were Pseudomonas aeruginosa, Staphylococcus aureus, and enteric bacilli. There were no statistically significant differences in clinical or microbiological and clinical cure or in the rates of adverse events between treatment groups.

CONCLUSIONS

Ofloxacin given twice daily is as safe and effective as Cortisporin given 4 times daily for otitis externa. The bacteriological findings and treatment responses do not differ between adults and children.

Bacterial flora of stethoscopes' earpieces and otitis externa

External otitis caused by Staphylococcus aureus was observed in a nurse after extensive use of a stethoscope. The infection recurred and a similar organism was isolated from the stethoscope's earpiece. The infection did not recur after the earpiece was cleansed after each use. In a prospective study, the bacterial flora of 35 earpieces was evaluated. Fifty-three isolates, 36 aerobic or facultative and 17 anaerobic, were recovered. The number of organisms per earpiece ranged from 14 to 204 (average 92 +/- 17). The predominant isolates were Staphylococcus epidermidis (16 isolates), Propionibacterium acnes (12), and Saureus (7). The study demonstrates the colonization of the stethoscope's earpiece with microorganisms that possess the potential for causing nosocomial infection.

Antimicrobial sensitivity in microorganisms isolated from canine otitis externa

It is important to test the antimicrobial sensitivity of the aetiological agents of otitis externa before starting treatment in order to prevent the development of antibiotic resistance in the microorganisms. In this study the sensitivity patterns in bacteria and yeasts isolated as aetiological agents from otitis externa were analysed. Antifungal and antibacterial activity tests were done using the automated system ATB Fungus and the classic diffusion test respectively. The azole compounds had the greatest antifungal properties, while beta-lactams had the strongest antibiotic activity. This study reflects the increasing importance of sensitivity tests in chronic otitis externa due to the increasing antimicrobial resistances in bacteria and yeasts. If it is necessary to initiate an empiric treatment before the results of the antimicrobial test, the application of miconazole or econazole for yeasts and oxacillin or amoxicillin-clavulanic acid against bacteria is recommended.

[Otitis externa among users of private swimming pools]

The purpose of this study was to detect risk factors for developing otitis externa (OE) with special regard to swimming in private pools in holiday houses. Data were collected in a retrospective case-control study from June to October in 1993 and over the same period in 1994. Patients who had OE diagnosed by a general practitioner were included. In 1993 controls were 134 guests from 27 holiday houses where nobody got o.e. during their stay. The number of cases was 35. In 1994 the design was changed so that controls were the 95 healthy inhabitants from the same houses as the 23 cases. The amounts of time spent in the pools and the total bacteria count in the water were significant risk factors for developing OE. Pseudomonas aeruginosa was found in 80% of the ear swabs of the casegroup. In 1993 30% and in 1994 83% of the pools fulfilled the requirements for public pools set by the Danish authorities.

[First isolation of Bilophila wadsworthia in otitis externa]

Bilophila wadsworthia is an obligately anaerobic, gram-negative rod, which was first described in 1989. The natural habitat of this species seems to be the lower intestinal tract where it was recovered from about 60% of the persons investigated. Bilophila wadsworthia is mainly associated with intra-abdominal infections, but the species was also isolated as part of aerobic-anaerobic mixed infections at various extra-abdominal sites. Otological infections due to Bilophila wadsworthia have as yet not been described. In the present paper, we report a case of a patient with postoperative otitis externa following stapedectomy, probably caused by the anaerobes Bacteroides fragilis and Bilophila wadsworthia.

Otomycosis: the detection of fungi in ears by immunofluorescence microscopy

The procedure currently used to diagnose infection in otitis externa has several limitations: it is slow to culture organisms on growth media, fungal infections are often missed, and extensive laboratory facilities and mycological expertise are required. A rapid, accurate and sensitive assay would greatly improve patient care by initiating appropriate antifungal treatment at the onset of disease. We report the development of a rapid detection assay for otomycosis using fungal-specific monoclonal antibodies to detect fungi in ear swabs by immunofluorescence microscopy. This assay could form the basis of a detection assay for fungal infections of the head and neck.

Necrotizing external otitis in patients with AIDS

In a retrospective review of seven patients with AIDS who were diagnosed with necrotizing external otitis between 1990 and 1995, it was found that the presentation of necrotizing external otitis in patients with AIDS differed from the classic description of malignant external otitis in several respects. The patient population was significantly younger and nondiabetic. Granulation tissue was usually absent from the external auditory canal and Pseudomonas aeruginosa was not the predominant pathologic organism. Also, outcome was found to be significantly worse. Thus a high index of suspicion must be entertained and vigorous local and systemic treatment initiated early in the course of disease to achieve a satisfactory outcome.

New combination for the therapy of canine otitis externa. I. Microbiology of otitis externa

In order to compound a new drug combination against canine otitis externa (OE), 515 dogs affected with OE were subjected to physical examination and microbiological analysis of their ear exudates. OE was erythematous-ceruminous in 83 per cent and suppurative in 17 per cent of the patient material. Erythematous-ceruminous inflammations were characterised by severe pruritus and accumulation of brownish, greasy cerumen in the auditory canal. The yeast Malassezia pachydermatis was isolated from the ears of 76 per cent of the dogs, often in combination with Staphylococcus intermedius bacteria. M pachydermatis showed the most sensitivity, in decreasing order of efficacy, to ketoconazole, econazole, clotrimazole, miconazole and nystatin. S intermedius isolates were most sensitive to amoxycillin-clavulanic acid, enrofloxacin, cephalexin and gentamicin. The microorganism most frequently isolated from dogs with suppurative OE was Pseudomonas aeruginosa; in some cases Proteus, Streptococcus and Pasteurella were also isolated. The P aeruginosa isolates showed the highest sensitivity to gentamicin, polymyxin B and tobramycin.

Microbiology of otitis externa

Microbiologic and clinical data from 26 patients with otitis externa were prospectively evaluated. Specimens were processed for aerobic and anaerobic bacteria. Bacterial growth was noted in 23 specimens. A total of 33 aerobic and 2 anaerobic bacteria were recovered. Aerobic bacteria only were isolated in 21 (91%) patients, anaerobic bacteria only in 1 (4%), and mixed aerobic and anaerobic bacteria in 1 (4%). The most common isolates were Pseudomonas aeruginosa (14 instances), Staphylococcus aureus (7), Acinetobacter calcoaceticus (2), Proteus mirabilis (2), Enterococcus faecalis (2), Bacteroides fragilis (1), and Peptostreptococcus magnus (1). One isolate was recovered in 13 (57%) patients, 2 isolates in 8 (35%), and 3 isolates in 2 (9%). These data illustrate the polymicrobial nature of otitis externa in about half of the patients and the role of anaerobic bacteria in 8% of them. Further studies are warranted to evaluate the therapeutic implications of these findings.