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

Pseudomonas aeruginosadose response and bathing water infection

Pseudomonas aeruginosais the opportunistic pathogen mostly implicated in folliculitis and acute otitis externa in pools and hot tubs. Nevertheless, infection risks remain poorly quantified. This paper reviews disease aetiologies and bacterial skin colonization science to advance dose-response theory development. Three model forms are identified for predicting disease likelihood from pathogen density. Two are based on Furumoto & Mickey's exponential ‘single-hit’ model and predict infection likelihood and severity (lesions/m2), respectively. ‘Third-generation’, mechanistic, dose-response algorithm development is additionally scoped. The proposed formulation integrates dispersion, epidermal interaction, and follicle invasion. The review also details uncertainties needing consideration which pertain to water quality, outbreaks, exposure time, infection sites, biofilms, cerumen, environmental factors (e.g. skin saturation, hydrodynamics), and whetherP. aeruginosais endogenous or exogenous. The review's findings are used to propose a conceptual infection model and identify research priorities including pool dose-response modelling, epidermis ecology and infection likelihood-based hygiene management.

Management of malignant (necrotising) otitis externa

Although malignant (necrotising) otitis externa is not a common diagnosis, there have been a number of recently reported cases with pathogens other than Pseudomonas aeruginosa as the causative organism. In addition, there are many published reports of resistance to antibiotics in cases of malignant otitis externa caused by Pseudomonas aeruginosa. This review aims to assess the cases reported and to clarify the current opinion on the diagnostic criteria and management of such cases.

Non-polar lipid components of human cerumen

Human cerumen was separated by column chromatography into the following groups of compounds: hydrocarbons, squalene, wax esters and cholesterol esters, triacylglycerols, free fatty acids, free fatty alcohols, monoacylglycerols, free cholesterol, free sterols, and free hydroxy acids. The groups of compounds obtained were examined in detail by gas chromatography and gas chromatography-mass spectrometry. In total, about one thousand compounds have been identified.

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.

Dexamethasone phosphate in antibiotic ear drops for the treatment of acute bacterial otitis externa

OBJECTIVES

To compare the efficacy and safety of polymyxin sulfate 7500 IU/neomycin sulfate 3500 IU/dexamethasone phosphate 0.1% (PN+Dx) otic solution with polymyxin sulfate 7500 IU/neomycin sulfate 3500 IU (PN-Dx) in patients with acute bacterial otitis externa (AOE), in order to determine the possible benefit of the addition of dexamethasone.

RESEARCH DESIGN AND METHODS

Active controlled, double-blind, randomized, parallel group, multi-center clinical trial in ear, nose, and throat (ENT) specialist practices with a planned interim analysis for sample size adaptation. In total, 338 patients aged 18-76 who had a previous episode of otitis externa within the last year were randomized to receive 10 +/- 2 days of treatment with two drops, three times daily, of either PN+Dx or PN-Dx.

MAIN OUTCOME MEASURES

Change in the clinical symptom score (consisting of the subscores redness, swelling, pain, and secretion) and of the visual analogue scale (VAS) rating for pain from Visit 1 (Day 1) to Visit 2 (Day 4 +/- 1), patient's assessment of efficacy at Visit 3 (Day 10 +/- 2), and the frequency and type of adverse events.

RESULTS

There was a significantly greater reduction of swelling from Visit 1 to Visit 2 with PN+Dx, and more patients rated the efficacy of PN+Dx as 'very good' or 'good' at Visit 3 (p = 0.03). There was also a significantly greater decrease in the clinical symptom score from Visit 1 to Visit 2 in the PN+Dx group in patients who had at least a moderately severe symptom score with more than seven points at Visit 1 (p = 0.01) and in patients suffering from their current episode of otitis externa for more than 2 days (p = 0.02). In total, 14 adverse events were reported during the study period with no related adverse drug reactions for PN+Dx.

CONCLUSIONS

The addition of dexamethasone phosphate to polymyxin B/neomycin significantly reduces swelling in patients with AOE and leads to significantly higher patient's ratings of treatment efficacy. It especially leads to an overall reduction of symptoms in cases of moderately or more severe otitis externa and cases lasting for more than 2 days.

Impacted cerumen: composition, production, epidemiology and management

In the UK, some 2.3 million people suffer cerumen ('ear wax') problems serious enough to warrant management, with approximately 4 million ears syringed annually. Impacted cerumen is a major cause of primary care consultation, and a common comorbidity in ENT patients, the elderly, infirm and people with mental retardation. Despite this, the physiology, clinical significance and management implications of excessive and impacted cerumen remain poorly characterized. There are no well-designed, large, placebo-controlled, double-blind studies comparing treatments, and accordingly, the evidence surrounding the management of impacted cerumen is inconsistent, allowing few conclusions. The causes and management of impacted cerumen require further investigation. Physicians are supposed to follow the edicts and principles of evidence-based medicine and clinical governance. Currently, in patients with impacted cerumen, the lack of evidence makes this impossible.

Has cerumen a protective role in recurrent external otitis?

PURPOSE

We investigated the bactericidal activity of the cerumen in patients with recurrent otitis externa.

MATERIALS AND METHODS

Cerumen samples were collected from 2 groups. Group A (n = 20) consisted of patients with recurrent otitis externa (2 or more acute otitis externa attack in the current year) and group B (n = 30) consisted of cerumen from a healthy population. We examined the bactericidal activity against the common microorganisms (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Enterococcus) that encounter the recurrent otitis externa.

RESULTS

A significant decrease in the count of S epidermidis was observed in group A (P <.05) and B (P <.01) was observed. A comparison of decreases and increases in the percentages of microorganisms between the groups A and B showed that there was a significant difference only in the count of E coli (P <or=.05). The count of E coli decreased in cerumen suspension in group A, but it increased in the normal population.

CONCLUSION

We did not confirm that cerumen from patients with recurrent otitis externa had less bactericidal activity than from a healthy population.