Update on antimicrobial susceptibilities of bacterial isolates from canine and feline otitis externa

The in vitro susceptibility of a total of 1819 bacterial isolates from canine and 103 isolates from feline otitis externa cases to 13 antimicrobial drugs over a 5-year period was evaluated. Among topically used drugs, 90% of isolates were susceptible to gentamicin. Susceptibility of Pseudomonas aeruginosa to gentamicin was 85%, and to polymyxin B 100%. For isolates other than the Pseudomonas sp., susceptibility was highest to amoxicillin-clavulanic acid.

Therapeutic Effects of .BETA.-Thujaplicin Eardrops on Canine Malassezia-Related Otitis Externa

An eardrop solution of beta-thujaplicin was examined for therapeutic effects on canine Malassezia-related otitis externa. Half to one ml of beta-thujaplicin solution of 100 microg/ml including DMSO 2% was injected everyday into both external ear canals of 31 cases for test-of-cure agreement. Fifteen score phases were established from the symptoms and cerumen smear biopsy findings, and score changes were recorded at least once a week. The means of the second and the third inspection day scores decreased significantly more than the previous value of each. In addition, the numbers of yeast-like organisms clearly decreased. These results suggest that beta-thujaplicin eardrops are effective for Malassezia-related otitis externa in dogs.

Atypical presentation of cutaneous tuberculosis and a retropharyngeal neck abscess

A 70-year-old Asian man with noninsulin-dependent diabetes presented with a 4-month history of left-sided otitis externa and right-sided facial palsy. Physical examination of the left ear revealed a punched-out ulcerative lesion on the tragus, an edematous and inflamed external auditory canal, and a purulent nonmucoid discharge. Computed tomography of the brain and neck demonstrated a large retropharyngeal abscess, an abscess in the left parapharyngeal space, and a small collection adjacent to the right carotid sheath at the level of C4; the cervical vertebrae and lungs were normal. Microscopy of drained pus and histology of left ear and neck node biopsies identified tuberculosis. The patient was started on antituberculosis drug therapy, but he died within 2 weeks of treatment. We discuss the characteristics of this unusual presentation of tuberculosis infection.

[RAPD differentiation of yeast like fungi Malassezia pachydermatis]

The aim of the work was analyzing of genomic DNA of Malassezia pachydermatis isolates from clinical cases otitis externa from dogs using RAPD method with arbitrary primers Eric 1R, Eric2, BG2 and FM1.

MATERIALS AND METHODS

47 strains of M. pachydermatis isolates from clinical cases otitis externa from dogs were tested. Isolation of genomic DNA was provided according with MasterPureTM Yeast DNA Purification Kit EPICENTRE procedure. The quality of isolated genomic DNA was determined electrophoreticaly. For differentiation the following primers were used: Eric1R, Eric2, BG2 and FM1. Primers Eric 1R and Eric 2 were used together in one reaction or amplificated separately. Obtained products were analyzed electrophoreticaly in 1.5% agarose gel. For determination of phylogenic tree Quantity one VersaDoc (BioRad) and Statgraphics plus 4.1 programs were used.

RESULTS

High degree of heterogeneity of DNA among investigated isolates of M. pachydermatis was shown using FM1 primer. Dendrograms were prepared by calculation euclid's distance of different parameters (size and count of RAPD products) by nearest neighbor method. Basing on phylogenic tree four main types (phylogenic groups) of M. pachydermatis isolates were shown. The other five groups non-count was shown also.

Necrotizing (malignant) otitis externa: An unusual localization of mucormycosis

Malignant otitis externa (MOE) is a severe infection of external auditory canal and skull base. A 17-year-old diabetic girl was admitted with diabetic ketoacidosis. Cellulitis of her right ear occurred on the second day of hospitalization and a black necrotic scar in the same region appeared on the next day. The lesion rapidly invaded to right side of neck and surrounding tissue of the patient. Therefore, antimycotic therapy was started. Unfortunately the patient died on seventh day of hospitalization because of probably extensive fungal invasion. Physicians should suspect MOE connected to mucormycosis especially in patients with cutaneous lesions of ear unresponsive to antibiotic therapy.

Necrotizing external otitis in a patient caused by Klebsiella pneumoniae

Necrotizing external otitis is a potentially life-threatening infection involving the temporal and adjacent bones. The most frequent pathogen is attributed to Pseudomonas aeruginosa, but is rarely caused by Klebsiella pneumoniae. Recently, we encountered a 47-year-old diabetic man with a swollen obliterated external ear canal with granulation tissue on the right ear. Image study demonstrated skull base osteomyelitis, epidural abscess and cerebral venous sinus thrombi. It was later proved to be necrotizing external otitis caused by Klebsiella pneumoniae. He then underwent craniotomy for drainage of the epidural abscess, followed by intravenous ciprofloxacin and metronidazole for 2 consecutive weeks until both pus and blood cultures depicted no growth of pathogens. Based on this case, synergistic antibiotic therapy using a third-generation cephalosporin or quinolone (ciprofloxacin), accompanied by metronidazole, and even a short-term aminoglycoside is recommended for the treatment of severe Klebsiella-induced necrotizing external otitis. Surgical intervention should be limited without shedding of the pathogens.

Fungal causes of otitis externa and tympanostomy tube otorrhea

OBJECTIVE

To describe the occurrence of fungal organisms in the setting of otitis externa and tympanostomy tube otorrhea, review the treatment course, timing of diagnosis, organism identified and time to resolution with fungal infections.

DESIGN

Retrospective review.

SETTING

Pediatric otolaryngology clinic within a tertiary care hospital.

PATIENTS

One hundred and sixty-six patients (ages 16 days to 18 years) with fungal organisms on ear culture.

OUTCOME MEASURES

Number of prior therapies, number of office visits, time to resolution and anti-fungal therapy.

RESULTS

Ear cultures positive for fungal organisms were found in 166 patients seen between 1 January 1996 and 30 September 2003 from a total of 1242 patients undergoing ear culture. Comparing the 3-year period (1996-1998) prior to the availability of fluoroquinolone ototopical drops to the 3-year period after (1999-2001), there is a statistically significant increase in the incidence of positive fungal culture (p<0.001). Otitis media was diagnosed in 72% of these children, with otitis externa comprising 25%. Approximately 3% carried a diagnosis of both otitis externa and otitis media. Candida albicans was identified in 43% of fungal organism-positive cultures. Candida parapsilosis was found in 24% of and Aspergillus fumigatus in 13%. The remainder of the cultures yielded three other Candida and three other Aspergillus species, each at less than 5%. Time to resolution ranged from 1 week to 9 months, with a median of 3.8 weeks for symptom resolution. Patients were treated with an average of 1.7 oral antibiotics and 1.1 ototopical agent before a culture was taken.

CONCLUSIONS

Otorrhea due to fungal organisms occurs in the setting of refractory infection and is often discovered after multiple oral and ototopical antibacterial medications. Due to the extended treatment period required to clear fungal organism, timely diagnosis with culture for bacteria and fungus is required in patients with persistent otorrhea. An increase in incidence of fungal infections of the ear was found in the period after widespread use of ofloxacin began.

Occurrence and Population Size of Malassezia spp. in the External Ear Canal of Dogs and Cats Both Healthy and with Otitis

Malassezia yeasts are commensal organisms of human and animal skin that occasionally act as pathogens; lipid-dependent species are associated with human skin disorders. The aim of this work was to evaluate the occurrence, risk factors and population size of different species of Malassezia in the external ear canal of dogs and cats with and without otitis externa. Between 2001 and 2003, 107 healthy animals (25 cats and 82 dogs) and 123 animals with chronic otitis exteirna (48 cats and 75 dogs) were clinically examined. Sterile cotton swabs were used to collect specimens from the external ear canal and culture tests and cytological examinations were performed to detect the presence and population size of Malassezia yeasts. Malassezia yeasts were isolated from 72.9% and 40% of the cats and from 57.3% and 28.0% of the dogs, with and without otitis externa, respectively. Malassezia was frequently isolated from animals under 5 years of age. The highest prevalence of positive samples was reported in winter for cats and in autumn for dogs. Dogs with pendulous ears showed a higher incidence of infection than dogs with erect ears. More Malassezia yeasts were recovered from animals with otitis (i.e. 59.6 colony forming units - CFUs - for cats and 66.0 CFUs for dogs) than healthy animals. Out of the 413 isolates obtained from animals with and without otitis, 403 (97.6%) were identified as M. pachydermatis and 10 (2.4%) as M. globosa. A statistical evaluation of the occurrence of Malassezia yeasts in dogs and cats revealed that predisposing factors for Malassezia infections are sampling period for cats, and type of ear for dogs. The largest population of Malassezia yeasts was detected in animals with otitis, suggesting a role in the occurrence of lesions.

Effect of tympanic cavity evacuation and flushing on microbial isolates during total ear canal ablation with lateral bulla osteotomy in dogs

OBJECTIVE

To evaluate differences in bacterial numbers, identity, and susceptibility in samples obtained from the tympanic cavity on entry (preflush) and after evacuation and lavage (postflush) and assess perioperative and empiric antimicrobial selection in dogs that underwent total ear canal ablation (TECA) with lateral bulla osteotomy (LBO) or reoperation LBO.

DESIGN

Prospective clinical study.

ANIMALS

34 dogs.

PROCEDURE

TECA with LBO or reoperation LBO was performed on 47 ears. Pre- and postflush aerobic and anaerobic samples were obtained from the tympanic cavity. Isolates and antimicrobial susceptibility patterns were compared.

RESULTS

Different isolates (31/44 [70%] ears) and susceptibility patterns of isolate pairs (6/44 [14%] ears) were detected in pre- and postflush samples from 84% of ears. Evacuation and lavage of the tympanic cavity decreased the number of bacterial isolates by 33%. In 26% of ears, bacteria were isolated from post-flush samples but not preflush samples. Only 26% of isolates tested were susceptible to cefazolin. At least 1 isolate from 53% of dogs that received empirically chosen antimicrobials postoperatively was resistant to the selected drugs. Anaerobic bacteria were recovered from 6 ears.

CONCLUSIONS AND CLINICAL RELEVANCE

Accurate microbiologic assessment of the tympanic cavity should be the basis for selection of antimicrobials in dogs undergoing TECA with LBO. Bacteria remain in the tympanic cavity after evacuation and lavage. Cefazolin was a poor choice for dogs that underwent TECA with LBO, as judged on the basis of culture and susceptibility testing results.

Gordonia otitidis sp. nov., isolated from a patient with external otitis

The taxonomic positions of two clinically isolated actinomycetes were established using a polyphasic approach. The two strains, IFM 10032T, isolated from ear discharge of a 28-year-old Japanese female patient with external otitis, and IFM 10148, isolated from pleural fluid of a 60-year-old Japanese male patient with bronchitis, possessed meso-diaminopimelic acid as the diagnostic amino acid, MK-9(H2) as the predominant menaquinone and mycolic acids ranging from 58 to 64 carbons. The 16S rRNA gene sequences of the two strains were most closely related to those of Gordonia aichiensis, Gordonia sputi and ‘Gordonia jacobaea’. Differences in several phenotypic characteristics together with genotypic distinctiveness distinguish strains IFM 10032T and IFM 10148 from these three species. DNA–DNA hybridization results and the combination of genotypic and phenotypic data showed that the two strains belong to a single species, and merit recognition of a novel species within the genus Gordonia. The name proposed for this taxon is Gordonia otitidis sp. nov.; the type strain is IFM 10032T (=DSM 44809T=JCM 12355T=NBRC 100426T).

Biofilm: why the sudden interest?

In recent years there has been increasing interest in the role of biofilms in perpetuating the chronicity and severity of bacterial infections. Enter the word biofilm as a search criterion with PubMed (National Library of Medicine) and you will doubtless be surprised to recover over 4000 citations, with nearly 3000 registered since 2000. So why has there been such an explosion of interest in this phenomenon? This article seeks to provide a brief overview of the subject, with particular reference to the role that biofilms may have to play in otologic disease.

Malignant external otitis: treatment with prolonged usage of antibiotics and Burow's solution

Malignant external otitis is a severe infection of the external auditory canal, generally caused by Pseudomonas aeruginosa in elderly diabetics patients. We describe a case of malignant external otitis in a 63-year-old man with severe otalgia, purulent otorrhea and polypoid granulation of the external auditory canal. Local debridement, insulin treatment and 6-week intravenous antibiotic therapy with carbapemens were very effective and the granulation tissue disappeared completely. However, the patient readmitted for recurrent disease 3 weeks later, despite the oral and ear drop administration with new quinolone. No recurrence has been noted after 4-week additional treatment with intravenous carbapenems followed by 3-week treatment with Burow's solution as ear drops.

Isolation and characterization of staphylococci from external auditory meatus of dogs with or without otitis externa with special reference to Staphylococcus schleiferi subsp. coagulans isolates

Staphylococci were isolated from the external auditory meatus in 14 (48.3%) of 29 dogs affected with otitis externa (OE dogs) and 28 (68.3%) of 41 dogs without OE (non-OE dogs). Twenty-two OE isolates were identified as belonging to 12 species, and 42 non-OE isolates were identified as belonging to 13 species. The predominant species found in both OE and non-OE isolates were S. intermedius, and S. epidermidis. Thirty-eight (59.4%) of 64 isolates were resistant to one or more of the 17 antimicrobial agents tested. Resistance to PCG and ABPC was most frequent. S. schleiferi subsp. coagulans, a recent etiologic agent of canine OE, was isolated from OE and non-OE dogs. All of the 5 S. schleiferi subsp. coagulans isolates showed typical characteristics. No clear difference in the extracellular enzyme or toxin profiles, nor in the PFGE patterns, was demonstrated between the OE and non-OE isolates of S. schleiferi subsp. coagulans. A new PCR primer set specific for 16S rDNA was designed to identify strains of S. schleiferi subsp. coagulans. The amplified fragment was detected in all of the 5 isolates as well as the type strain GA 211 (=JCM 7470) and a reference strain GA 11, but was not detected in any strains of the related species, S. aureus, S. intermedius and S. hyicus. The PCR may allow a simple, rapid and precise identification of S. schleiferi subsp. coagulans, in addition to the standard tube test for free coagulase.

Infections of the external ear

Otitis externa is one of the most common conditions seen in the otolaryngology practice. It encompasses a wide range of conditions, from those that cause mild inflammation and discomfort to those that are life-threatening. The management of these conditions requires a clear understanding of the anatomy and physiology of the ear canal, the microbiology of pathogens and familiarity with the clinical presentation.

Severe otitis due to Vibrio fluvialis in a patient with AIDs: first report in the world

A case of waterborne otitis in a patient with AIDS was reported, who got infected with Yibrio fluvialis by swimming in a pool of sea water. This is the first case reported in Cuba and as far as we know in the world. We describe the clinical features associated with this an unusual case and discuss its significance.

External otitis caused by infection with Pseudomonas aeruginosa or Candida albicans cured by use of a topical group III steroid, without any antibiotics

CONCLUSIONS

Irrespective of the microbial agent, group III steroid solution cured external otitis efficiently in a rat model. The addition of antibiotic components to steroid solutions for the treatment of external otitis is of questionable validity.

OBJECTIVE

External otitis, caused by infection with either Pseudomonas aeruginosa or Candida albicans, was established in a rat model and the treatment efficacy of a group III steroid solution was studied.

MATERIAL AND METHODS

Three treatments were studied: (i) a group III steroid solution; (ii) a group I steroid combined with two antibiotic components; and (iii) a saline solution. A scoring scale was used to evaluate the characteristics of the ear canal skin. Bacteriological and fungal samples were collected for culturing and ear canal skin biopsies were taken for structural analyses.

RESULTS

It was possible to cause P. aeruginosa and C. albicans infections in an animal model. In the P. aeruginosa-infected animals, only the group III steroid treatment cured all the animals. In the C. albicans-infected animals, group III steroid treatment resolved external otitis faster than the other treatment modalities.

Otomycoses of candidal origin in eastern Slovakia

Mycological analysis of swabs and scraping samples from the external ear canals of 40 patients with clinically diagnosed otomycosis (10 neonates, 30 adults) revealed the presence of fungi as etiological agents. They were investigated microscopically using 20 % potassium hydroxide, and by cultivation on Sabouraud's glucose agar. The Candida species were identified using the germ-tube test, micromorphology observations of colonies on rice agar, and particularly by the commercial kit AUXAcolor. The following Candida species were identified in the aural material examined: C. albicans (n = 21; 52.5 %), C. parapsilosis (11; 27.5), C. tropicalis (3; 7.5), C. krusei (3; 7.5), C. guilliermondii (2; 5.0). The above yeasts were present in samples together with Staphylococcus epidermidis (31), S. aureus (16), alpha-hemolytic streptococci (14), Neisseria spp. (14), Proteus mirabilis (3), Pseudomonas aeruginosa (3), Escherichia coli (1) and Haemophilus influenzae (1). The most frequent predisposing factors for otomycosis were swimming in public pools and/or bath, spa and diabetes mellitus.

Clinical evaluation of the electronic nose in the diagnosis of ear, nose and throat infection: a preliminary study

The term electronic nose describes an electronic system that is able to mimic the human sense of smell. Electronic noses have been developed over the last 10 or more years to perform a variety of identification tasks in various industries. More recently electronic noses have attracted new interest in their application in the field of medical diagnosis. The aim of this study is to explore the use of an electronic nose to identify and classify pathogens associated with ear, nose and throat (ENT) infections. In this study 90 bacterial swab samples were collected from 90 patients with ENT infections. Some of these samples were analysed immediately with a commercial electronic nose (Cyranose C320). Similar numbers of swabs were also taken from the same site of infection and were sent for microbiology culture and sensitivity. The electronic nose diagnosis was compared with the microbiology diagnosis and it was found that the electronic nose diagnosis was correct in 88.2 per cent of the cases, which is an encouraging result.

Microbiological features of Staphylococcus schleiferi subsp. coagulans, isolated from dogs and possible misidentification with other canine coagulase-positive staphylococci

Staphylococcus schleiferi subsp. coagulans has only rarely been isolated and identified from the external auditory meatus of dogs suffering from external otitis. Its morphological and basic biochemical characteristics are of relatively little value for identification, as it phenotypically resembles another coagulase-positive staphylococci (CPS) and, consequently, may be easily misidentified as S. intermedius or even as S. aureus. In the present work, differentiation of S. schleiferi ssp. coagulans was therefore based on specific biochemical and genetic methods. All the strains were evaluated with the following commercial methods: Api Staph System (bioMérieux, Marcy l'Etoil, France), BBL Crystal Identification Systems (Gram-Positive ID Kit and Rapid Gram-Positive ID Kit; Becton Dickinson), and GEN-PROBE AccuProbe, Staphylococcus aureus identification test (bioMérieux). Gram-Positive ID System/GP database includes the broadest range of staphylococcal species and correctly identifies the majority of strains important in veterinary medicine. Therefore, it is an acceptable alternative to conventional methods for identification of canine staphylococcal isolates. Reliable differentiation of S. aureus from S. schleiferi ssp. coagulans and S. intermedius was feasible with AccuProbe for S. aureus, which gave positive results only for S. aureus; all other CPS tested were negative.

Comparison of bacterial organisms and their susceptibility patterns from otic exudate and ear tissue from the vertical ear canal of dogs undergoing a total ear canal ablation

The purpose of this prospective study was to compare bacterial organisms and their susceptibility patterns from otic exudate and ear tissue from the vertical ear canal of six dogs with end-stage otitis undergoing a total ear canal ablation. Twenty-six organisms, 13 from the exudate and 13 from the tissue, were morphologically and biochemically similar, and their susceptibility patterns were compared. There were discrepancies for only 5 antibiotics for 4 organisms from 3 dogs. Culture of otic exudate from the vertical ear canal of dogs with chronic end-stage otitis externa provides an accurate reflection of the bacterial species present and the antimicrobial susceptibility patterns of these infections.

Efficacy of Boric-Complexed Zinc and Acetic-Complexed Zinc Otic Preparations for Canine Yeast Otitis Externa

The purpose of this 2-week, double-blinded, controlled clinical trial was to evaluate the efficacy of topical amino acid-complexed zinc gluconate formulated with boric acid (ZGB) or acetic acid (ZGA) versus a topical placebo in the treatment of yeast otitis externa in dogs. Included in the study were dogs with otitis externa and a cytopathological finding of yeast organisms in the affected ear. Ears were treated with the placebo, ZGA, or ZGB medications. Yeast counts as well as clinical appearance of the ears were monitored. Results revealed that ZGB significantly reduced the number of yeast organisms in cases of otitis externa.

Effects of .BETA.-Thujaplicin on Anti-Malassezia pachydermatis Remedy for Canine Otitis Externa

The antifungal activity of beta-thujaplicin was evaluated against 51 Malassezia pachydermatis strains isolated from canine ear canals with or without otitis externa. For comparison, sensitivity tests were performed on M. pachydermatis isolates for nystatin, ketoconazole, and terbinafine HCl, all clinically available antifungal agents. The minimal inhibition concentrations over 50% of the tested isolates (MIC50) were 3.13 microg/ml for beta-thujaplicin and nystatin, 0.016 microg/ml for ketoconazole, and 1.56 microg/ml for terbinafine HCl. The antifungal effect for M. pachydermatis of beta-thujaplicin compared favorably with commercial antifungal agents. None of the 51 M. pachydermatis isolates showed resistance against any of the tested antibiotics investigated in this study. Ten representative isolates of M. pachydermatis were subcultured for 30 generations at concentrations close to the MIC levels of beta-thujaplicin, nystatin, ketoconazole, and terbinafine HCl, and examined to determine whether they had acquired resistance to each drug. As a result, M. pachydermatis was found to achieve resistance more easily for ketoconazole and terbinafine HCl than for beta-thujaplicin or nystatin. The MIC50 of beta-thujaplicin did not change during the course of subculture, and it is thought that the potential development of a resistant strain is low, even with continuous infusion for otitis externa therapy. beta-Thujaplicin is an inexpensive and safe treatment with anti-inflammatory and deodorant effects that can be recommended as an effective remedy for canine otitis externa.