BackgroundColonization of the body is an important step in Staphylococcus aureus infection. S. aureus colonizes skin and mucous membranes in humans and several animal species. One important ecological niche of S. aureus is the anterior nares. More than 60% of the S. aureus in the nose are found in vestibulum nasi. Our aim was to describe the localization of S. aureus in nasal tissue from healthy carriers.MethodsPunch skin biopsies were taken from vestibulum nasi from healthy volunteers (S. aureus carriers and non−/intermittent carriers, n = 39) attending the population-based Tromsø 6 study. The tissue samples were processed as frozen sections before immunostaining with a specific S. aureus antibody, and finally evaluated by a confocal laser-scanning microscope.ResultsOur results suggest that S. aureus colonize both the upper and lower layers of the epidermis within the nasal epithelium of healthy individuals. The number of S. aureus in epidermis was surprisingly low. Intracellular localization of S. aureus in nasal tissue from healthy individuals was also detected.ConclusionsKnowledge of the exact localization of S. aureus in nasal tissue is important for the understanding of the host responses against S. aureus. Our results may have consequences for the eradication strategy of S. aureus in carriers, and further work can provide us with tools for targeted prevention of S. aureus colonisation and infection.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-017-0997-3) contains supplementary material, which is available to authorized users.

Cisplatin is associated with a hearing loss particularly at higher frequencies. Age appear to be an important factor for hearing loss regardless of treatment. The ASHA definition overestimates the hearing problem.

The purpose of this study was to analyse the changes in pure-tone hearing thresholds with age. We studied a random sample of 232 elderly subjects with a battery of audiological tests, including pure-tone audiometry in the conventional and extended high-frequency range, using the normative distributions from the International Organization for Standardization (ISO) standard 7029 for comparison. Sixty otologically normal (ON) subjects were selected for comparative analysis with the unscreened (US) sample, and for description of gender and age group differences. With the use of a mathematical transformation of threshold data, it was found that the ISO 7029 normative alpha coefficient in females may be set too low compared to our sample in the lower frequencies, leading to an underestimation of hearing thresholds in ON females. In our ON sample, hearing thresholds deteriorated with age in the extended high-frequency audiometric range. No gender threshold differences were found, although the prevalence of unmeasurable responses was higher in males at some of these frequencies. The ON screening criteria in ISO 7029 may be unreliable in subjects over 60 years of age, as threshold differences between ON and US subjects were not consistent at any frequency.

No change in middle ear sound transmission, as assessed by tympanometry, occurs with normal aging. Ear canal volume is smaller in elderly females than elderly males, which is potentially relevant to the study of otoacoustic emissions in the elderly. The estimated prevalence of ear canal-related problems, excluding cerumen obstruction, is of such a magnitude that the introduction of partially implanted hearing aids may be warranted in our elderly population.