Cerumen microbial community shifts between healthy and otitis affected dogs.

Otitis externa is a common multifactorial disease in dogs, characterized by broad and complex modifications of the ear microbiota. The goal of our study was to describe the ear cerumen microbiota of healthy dogs, within the same animal and between different animals, and to compare the cerumen microbiota of otitis affected dogs with that of healthy animals. The present study included 26 healthy dogs, 16 animals affected by bilateral otitis externa and 4 animals affected by monolateral otitis externa. For each animal cerumen samples from the right and left ear were separately collected with sterile swabs, and processed for DNA extraction and PCR amplification of the 16S rRNA gene. Amplicon libraries were sequenced using an Ion Torrent Personal Genome Machine (PGM), and taxonomical assignment and clustering were performed using QIIME 2 software. Our results indicate that the bacterial community of the cerumen in healthy dogs was characterized by extensive variability, with the most abundant phyla represented by Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes and Fusobacteria. The analysis of both alpha and beta diversity between pairs of left and right ear samples from the same dog within the group of affected animals displayed higher differences than between paired samples across healthy dogs. Moreover we observed reduced bacterial richness in the affected group as compared with controls and increased variability in population structure within otitis affected animals, often associated with the proliferation of a single bacterial taxon over the others. Moreover, Staphylococcus and Pseudomonas resulted to be the bacterial genera responsible for most distances between the two groups, in association with differences in the bacterial community structure. The cerumen microbiota in healthy dogs exhibits a complex bacterial population which undergoes significant modifications in otitis affected animals.

Cerumen impaction was composed of abnormal exfoliation of keratinocytes that was correlated with infection.

OBJECTIVE: This study investigated the exact composition and tried to be helpful in explaining the etiologic mechanism of cerumen impaction in the external auditory canal (EAC). METHODS: A hundred impacted cerumen samples and 15 normal cerumen samples were collected by manual removal and divided into 2 groups. All samples were examined via microbial culture, hematoxylin-eosin staining, periodic acid-Schiff staining, and fungal fluorescent staining. RESULTS: Eighty-eight patients in group 1 were in the habit of using cotton buds. Forty-seven impacted cerumen samples tested positive for microbes, while only 1 sample of normal cerumen tested positive for microbes (p < .05). The most commonly isolated bacterium and fungus was Staphylococcus aureus and Aspergillus terreus respectively. All cerumen samples were composed of exfoliated keratinocytes and microorganisms assessed via pathologic examination. However, unlike normal cerumen, impacted cerumen contained nucleated keratinocytes and infiltrated neutrophils. Recurrent impaction was found only among patients who tested mold culture-positive. CONCLUSION: Impacted cerumen is composed of abnormal exfoliated keratinocytes that was correlated with microbial-induced neutrophil-mediated inflammation. Mold infection is highly correlated with recurrent cerumen impaction. Microbial culture of removed impacted cerumen is strongly recommended. Ear cleaning with cotton buds, particularly when the EAC is wet might be one of the important causes of cerumen impaction which is need further studied. LEVEL OF EVIDENCE: 2b.

Successful treatment of a recurrent Aspergillus niger otomycosis with local application of voriconazole.

Fungal otitis (otomycosis) is a common infection encountered by otolaryngologists. Nevertheless, its management can be challenging because of its high recurrence rate and of the limited therapeutic options. A 45-year-old woman suffered from recurrent otomycosis. The ineffectiveness of successive antibiotic cures and repeated topical treatments with nystatin and then with econazole cream led to perform microbiological analyses. Culture of ear swab grew Aspergillus niger. The use of a 1% voriconazole sterile solution previously validated for treatment of eye infections was considered after ensuring the absence of known ototoxic effects of the antifungal and of the excipients. The patient was advised to apply locally this voriconazole solution daily for 14 days (3 drops, 3-4 times a day). Full recovery was obtained at the end of the treatment, and no relevant side effects were noticed. More than one year after completion of therapy, there was no recurrence. Our observation shows that voriconazole 1% solution is an interesting option for treating otomycosis which failed to respond to usual therapeutic options. Further prospective studies are now warranted to confirm these findings.

Lipolytic, proteolytic, and cholesterol-degrading bacteria from the human cerumen.

Cerumen, also known as ear wax, is a yellowish waxy substance secreted from specialized glands in the ear canal of mammals. Human cerumen is rich in protein (mainly keratin), lipids (long-chain fatty acids), alcohols, squalene, and cholesterol. To-date the role of cerumen is not totally clear but it is believed to have antimicrobial properties. Here we describe the isolation of multiple bacterial species from human cerumen (among them many Staphylococcus spp. and, interestingly, multiple Bacillus spp.) showing that many of these bacteria harbor biochemical traits enabling them to utilize different cerumen components for their growth. We also suggest the existence of microbial consortia.

Association of Raillietia caprae with the presence of Mycoplasmas in the external ear canal of goats.

We did a descriptive study to determine whether the presence in the external ear canal of the Raillietia caprae mites and Mycoplasmas were associated. For that we sampled 360 goats slaughtered at abattoirs in the summer to identify those infested with the mite. We found only 20 infested, so used all of those plus another 47 uninfested goats selected systematically from the population negative for the isolation of Mycoplasmas. These goats came from the regions of Queretaro, Guanajuato, Sinaloa and Estado de México. Sterile swabs were taken from each ear canal of the carcass after removal of the pinna for microscopic observation of the mites and for the isolation of Mycoplasmas in both study groups. The swab samples were inoculated in Friis media for the isolation of Mycoplasmas; then, the isolates were biochemically characterized and identified serologically. We recovered isolates from the earwax of only nine of the 47 control goats, but from the earwax of 11 of the 20 infested goats; another four infested goats had Mycoplasma isolated from the mites but not from the earwax. Mycoplasma cottewii and Mycoplasma yeatsii were the only Mycoplasmas isolated from the uninfested goats, and also were the predominant (29 of 34) isolates from the infested goats and/or from the mites.

Antibacterial and antifungal properties of human cerumen.

OBJECTIVE: To assess the antibacterial and antifungal properties of human cerumen by studying its effect on the growth of Staphylococcus aureus, Esherichia coli, Pseudomonas aeruginosa and Candida albicans. MATERIALS AND METHODS: Cerumen samples were collected from 75 normal, healthy subjects aged from seven to 80 years, without ear pathology, who attended the ear, nose and throat out-patient clinic of the University Malaya Medical Center from May 2006 to October 2006. Of these 75 samples, 31 had no growth when cultured on nutrient agar. Inhibition studies on these 31 samples were performed for Staphylococcus aureus (American Type Culture Collection (ATCC) 25923), Esherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Candida albicans. Nutrient agar was used to conserve all three bacterial strains and Sabouraud dextrose agar was used for Candida albicans. RESULTS: A decrease in Staphylococcus aureus growth was observed for 27 of the 31 samples. All 31 samples induced decreased growth of Pseudomonas aeruginosa, while 29 induced decreased growth of Candida albicans. However, only four samples induced decreased growth of Escherichia coli. CONCLUSIONS: Cerumen was demonstrated to have potential antimicrobial effects on strains of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans.

Malassezia otitis externa in the dog: the effect of heat-fixing otic exudate for cytological analysis.

This study was conducted on 32 dogs with Malassezia otitis externa to determine the effect of heat-fixing otic exudate on cytological analysis. Malassezia infection was confirmed by cytological examination of otic exudate. Otic discharge collected with cotton swabs was then rolled onto glass slides. One slide per dog was heat-fixed prior to staining; the other slide was not heat-fixed. The number of yeast in 10 oil-immersion fields (1000 x magnification) was counted for both slides from each dog. Heat-fixing did not systematically cause either increased or decreased numbers of Malassezia on cytology of otic exudate.

Isolation of Malassezia spp. from cerumen of wild felids.

The objective of this study was to determine the presence of different species of the genus Malassezia in the healthy external auditory canal of wild felids maintained in captivity. One hundred and thirty-two adult animals (264 samples of cerumen), 77 males (58.3%) and 55 females (41.7%), were studied: large felids (55 animals) - 26 lions (Panthera leo), 13 tigers (Panthera tigris), 6 leopards (Panthera pardus), 6 jaguars (Panthera onca), 2 cheetahs (Acinonyx jubatus), 2 pumas (Puma concolor); small felids (77 animals) - 29 tiger cats (Leopardus tigrinus), 19 jaguarundis (Herpailurus yagouaroundi), 10 margays (Leopardus wiedii), 9 pampas cats (Oncifelis colocolo), 6 geoffroy's cats (Oncifelis geoffroyi), and 4 servals (Leptailurus serval). Samples were obtained by the introduction of a sterile swab into the ear canal after cleaning the auricle with an alcohol-ether solution. The swabs were seeded onto Petri dishes containing modified Mycosel agar and sterile olive oil was added to the surface of the medium before specimen seeding. The plates were incubated at 35oC for two weeks. The isolates were analyzed regarding macro-and micromorphology and identified through catalase tests and growth on Tween 20, 40, 60 and 80. Malassezia spp. were isolated from 58 of the felids studied (43.9%) and from 102 samples of cerumen (38.6%). Malassezia sympodialis was isolated exclusively in large felids (33 animals-56.9%), and Malassezia pachydermatis exclusively in smaller varieties (25 animals - 43.1%). The incidence of fungi was higher in lions, with yeast being isolated in 25 of 26 animals (96.2%). Forty-eight strains (47.1%) were isolated from the right ear canal and 54 (52.9%) from the left. Although M. pachydermatis is the species considered a member of the microbiota of the mammalian external ear canal these results suggest that M. sympodialis participates in the microbiota of large felids.

Are tympanic thermometers a source of cross-infection?

AIM: To find out if tympanic thermometers are a source of cross-infection in critical care and whether cleaning is effective. METHOD: An observational study. RESULTS; In most of the inspections the surfaces of the tympanic thermometers looked clean, but three inspections revealed spots of dried fluid and one revealed a dirty base. None of the swabs taken before or after cleaning was positive, but seven of the inspections identified that the lens of the tympanic thermometer was dirty, poSsibly with cerumen (earwax). CONCLUSION: The findings from this study do not support the assumption that tympanic thermometers are a source of cross-infection in critical care, but a potential risk of cross-infection by this route cannot be excluded.

Microbiology of cerumen in patients with recurrent otitis externa and cases with open mastoidectomy cavities.

This study investigated the common flora of human cerumen in patients with recurrent otitis externa, and subjects who had been operated on and had an open mastoidectomy cavity from chronic otitis media. Cerumen samples were collected from three groups; group A (n = 20) consisted of patients with recurrent otitis externa, group B (n = 20) consisted of patients with an open cavity and group C (n = 30) consisted of healthy subjects. The mean of the microbial count was 3.4 x 10(4) in group A, 3.08 x 10(4) in group B and 2.48 x 10(4) in group C. The most commonly isolated microorganism from the three groups was Staphylococcus epidermidis. No growth was observed in five cases (25 per cent) in group A and in three cases (10 per cent) in group C. In group B antimicrobial growth was observed in all samples. In 46 (65 per cent) of the cerumen samples, the isolates were monomicrobial and 24 (35 per cent) of the cerumen samples were polymicrobial. The isolates were polymicrobial in 65 per cent of group A, 20 per cent in group B and 23.3 per cent in group C. In the process of investigating the microbial flora of cerumen in all the three groups, microbial growth was observed from all the samples from patients with an open cavity, unlike the other groups, and it was determined that the group with recurrent external otitis had the most abundant microbial flora.

Chronic bilateral otomycosis caused by Aspergillus niger.

Aspergillus niger, an opportunistic filamentous fungus, was identified as the cause of chronic bilateral otomycosis in a 46-year-old female patient who was unresponsive to different drugs. The patient showed signs of erythema, otalgia, itching, otorrhoea and presence of greyish black coloured mass in both the ear canals. The direct microscopical examination of the ear debris in potassium hydroxide preparations, Giemsa, phase contrast and Gram revealed many thin, branched septate hyphae, condia and conidiophores morphologically indistinguishable from Aspergillus spp. The histopathological section of the ear wax mass by haematoxylin and eosin and periodic acid-Schiff techniques also showed similar fungal elements. The patient responded to 1% solution of mercurochrome. The use of mercurochrome in developing countries like India may be recommended to treat the fungal otitis in patients. We also emphasize that 'Narayan' stain should be routinely employed by microbiology and public health laboratories to study the morphology of pathogenic fungi.

Trichophyton rubrum in the external auditory meatus.

We report the case of a 28-year-old immunocompetent male suffering from otitis externa. The right external auditory meatus was filled with cerumen and detritus, the tympanic membrane covered wallpaper-like with layers of fungi. Mycological analysis revealed Trichophyton rubrum. With further examination tinea pedis of plantar and interdigital type and concomitant onychomycosis of the toenails due to T. rubrum could be detected. The auditory meatus was cleaned and treated topically with clotrimazole. Two weeks later the auditory meatus and the tympanic membrane were bare of fungi and the inflammation was resolved. Treatment of tinea pedis and onychomycosis with terbinafine (systemically and topically) is still lasting.

Real-time quantitative PCR for the detection of Streptococcus pneumoniae in the middle ear fluid of children with acute otitis media.

PCR based on the amplification of pneumolysin gene fragments has previously been applied to demonstrate Streptococcus pneumoniae in clinical specimens. Here, a real-time PCR method for the detection and quantification of pneumococci by amplifying a 206-bp fragment of the pneumolysin-encoding gene is described. The amplified fragments were detected simultaneously using fluorescent-labeled sequence-specific hybridization probes. The applicability of the assay to clinical samples was evaluated by studying 50 middle ear fluid (MEF) specimens from children with acute otitis media. Twenty-six of the MEF samples were positive by real-time PCR and the numbers of genome equivalents detected varied from 90 to 88,000/microl in 17 culture-positive samples and from 1 to 1,200/microl in 9 culture-negative samples. The results were compared to culture findings and to results obtained by using agarose gel electrophoresis or Europium-labeled hybridization probes for the detection of amplification products of conventional PCR. The sensitivity and specificity of the real-time PCR assay developed in the present study compared to culture were 100 and 73%, and to conventional PCR with agarose gel and/or TRF detection 93 and 96%, respectively. The real-time PCR assay was found to be rapid, easy to use, and sensitive in detecting and quantifying pneumococci.

Attachment of Malassezia pachydermatis to the ear dermal cells in canine otitis externa.

To investigate the predominance of Malassezia pachydermatis (M. pachydermatis) as a causative agent of canine otitis externa, ear cerumen samples were observed for adhesion of M. pachydermatis to the cornified epithelial cells by light and electron microscopes. The yeasts appeared not to adhere to the cornified epithelial cells directly, but they seemed to exist in the proximity of the epithelial cells with an electron opaque halo-like space around them. Polysaccharide and lipid staining techniques were conducted to identify the substances existing in that space. Lipid substances, not saccharides, were observed around the yeasts and the cornified epithelial cells. These results suggested that in the canine ear canal malassezia yeast attachment to the cornified epithelial cells is mediated by lipids.

Microbiology of normal external auditory canal.

OBJECTIVES: To isolate and characterize bacteria and fungi from the healthy ear and to obtain susceptibility profiles on each bacterial isolate. STUDY DESIGN: Prospective. METHODS: Specimens were collected from the external canals and cerumen of healthy subjects. Species-level identification was obtained by combining phenotypic and genotypic data. End-point minimal inhibitory concentration testing was performed using National Committee for Clinical Laboratory Standards recommended methods. RESULTS: One hundred sixty-four subjects were cultured. Seventeen canal and 16 cerumen specimens showed no growth. One hundred forty-eight cerumen specimens yielded 314 organisms, including 23 fungi. One hundred forty-seven canal specimens yielded 310 organisms, including 7 fungi. Of 291 bacteria isolated from cerumen, 99% were Gram-positive. Of 302 bacteria isolated from the canal, 96% were Gram-positive. Staphylococci were 63% of both the cerumen bacteria and the canal bacteria. Coryneforms represented 22% of the bacteria in cerumen and 19% in the canal. Turicellaotitidis was the primary coryneform isolated from both the canal and the cerumen. Streptococci-like bacteria were 10% from the cerumen, 7% from the canal. In both cerumen and canal, Alloiococcusotitis was more than 95% of the streptococci-like bacteria. Fifteen gram-negative organisms were isolated from the canal and cerumen, including four Pseudomonas aeruginosa strains. The percentages of Staphylococcus epidermidis isolates that had high-level resistance (> or =8 microg/mL) were as follows: to neomycin, 28% from cerumen and 11% from the canal; to oxacillin, 28% from cerumen and 25% from the canal; and to ofloxacin, 15% from cerumen and 19% from the canal. CONCLUSIONS: Turcellaotitidis and A. otitidis were present with a much higher frequency than previously described, lending evidence that they be considered normal otic flora. Corynebacterium auris, previously reported only in children, was isolated from normal adults.

Influence of human wet cerumen on the growth of common and pathogenic bacteria of the ear.

The available data on the effect of human wet cerumen on bacterial growth are not conclusive. Nevertheless it is widely accepted that cerumen has a bactericidal effect. In this study the activity of human wet cerumen on bacterial growth was assessed by applying cerumen suspensions to bacterial cultures. Bacterial counts were performed before and after application of cerumen suspensions. A total of 383 assays was carried out with 73 pools of cerumen that were tested against cultures of Staphylococcus aureus, Staphylococcus epidermidis, Corynebacterium spp., Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Serratia marcescens. An increase in growth occurred much more frequently than a decrease in growth in almost every microrganism tested, with the mean increase percentage being much higher than the mean decrease percentage, except in the case of S. aureus. The largest average growth increase was obtained with E. coli. The largest average decrease in bacterial growth was recorded with S. marcescens. Our study does not support the conception of a decrease in bacterial growth produced by humen wet cerumen. In vitro, the most observable effect was in fact an increase in microbial growth.

Study of common aerobic flora of human cerumen.

Cerumen is the product of the secretion of the sebaceous, ceruminous or apocrine glands together with cells exfoliated from the cornified stratum of the epithelium of the external auditory canal (EAC). In the present study we identified and quantified common flora of human cerumen. The mean count obtained was 10(6) microorganisms per ml of cerumen suspension. In 24 pools of cerumen (33.3 per cent) the isolates were monomicrobial, Staphylococcus epidermidis (12), Corynebacterium spp (10), Staphylococcus aureus (1) and Streptococcus saprophyticum (1). In 48 pools (66.6 per cent) we found polymicrobial isolates. The most commonly isolated bacteria in these polymicrobial isolates were S. epidermidis (35) and Corynebacterium spp. (43). It is noteworthy that there were isolates of Candida albicans in three cases; in one case of Pseudomonas stutzeri, in one case of Pseudomonas aeruginosa, and, on seven occasions, of S. aureus. The organisms isolated as common bacterial components of human cerumen in our experience were similar to those found by other authors. However, the mean count was much higher. This could be related to climatic conditions and to the length of time the cerumen had remained in the external auditory canal.

[Bacteriologic detection and sensitivity determination combined: a rapid test for use in practice?]. / Bacteriologisch onderzoek en gevoeligheidsbepaling inéén: een sneltest voor de praktijk?

In this investigation the results obtained with a testkit for detecting bacteria and their antibiotic sensitivity (ABcheck, Vétoquinol) were compared with those obtained using standard bacteriological procedures. Ten urine samples, ten skin samples, and ten cerumen samples were examined in parallel. The results indicate that the testkit is not reliable with respect to whether antibiotics should be administered and with respect to which antibiotics should be used.

[The anti-infective properties of mammalian earwax]. / Ob antiinfektsionnykh svoistvakh ushnoi sery mlekopitaiushchikh.

The cerumen (earwax) of some mammals possesses antistaphylococcal, antimicrococcal and antiherpes activities. The cerumen of two thirds of individuals, irrespective of their species identity and sex, has antiviral properties. The mean chemotherapeutical index in the studied groups follows a significantly decreasing sequence: dogs, humans without signs of herpes infections, rabbits, and humans with clinically expressed herpes infection. Cerumen of almost 25% of humans of the compared groups displays the immunostimulating activity. The cerumen of all studied individuals contains yeast-like fungi. A suggestion is put forward that the products of their metabolism stimulate local release of interferon-like substances by the lymphoid tissue in the cerumen.