Dataset Information

Chronic suppurative otitis media causes macrophage-associated sensorineural hearing loss.

ABSTRACT:

Background

Chronic suppurative otitis media (CSOM) is the most common cause of permanent hearing loss in children in the developing world. A large component of the permanent hearing loss is sensory in nature and our understanding of the mechanism of this has so far been limited to post-mortem human specimens or acute infection models that are not representative of human CSOM. In this report, we assess cochlear injury in a validated Pseudomonas aeruginosa (PA) CSOM mouse model.

Methods

We generated persisters (PCs) and inoculated them into the mouse middle ear cavity. We tracked infection with IVIS and detected PA using RT-PCR. We assessed cochlear damage and innate immunity by Immunohistochemistry. Finally, we evaluated cytokines with multiplex assay and quantitative real-time PCR.

Results

We observed outer hair cell (OHC) loss predominantly in the basal turn of the cochlear at 14 days after bacterial inoculation. Macrophages, not neutrophils are the major immune cells in the cochlea in CSOM displaying increased numbers and a distribution correlated with the observed cochlear injury. The progression of the morphological changes suggests a transition from monocytes into tissue macrophages following infection. We also show that PA do not enter the cochlea and live bacteria are required for cochlear injury. We characterized cytokine activity in the CSOM cochlea.

Conclusions

Taken together, this data shows a critical role for macrophages in CSOM-mediated sensorineural hearing loss (SNHL).

SUBMITTER: Xia A

PROVIDER: S-EPMC9465898 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature

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Publications

Chronic suppurative otitis media causes macrophage-associated sensorineural hearing loss.

Xia Anping A Thai Anthony A Cao Zhixin Z Chen Xiaohua X Chen Jing J Bacacao Brian B Bekale Laurent A LA Schiel Viktoria V Bollyky Paul L PL Maria Peter L Santa PLS

Journal of neuroinflammation 20220912 1

<h4>Background</h4>Chronic suppurative otitis media (CSOM) is the most common cause of permanent hearing loss in children in the developing world. A large component of the permanent hearing loss is sensory in nature and our understanding of the mechanism of this has so far been limited to post-mortem human specimens or acute infection models that are not representative of human CSOM. In this report, we assess cochlear injury in a validated Pseudomonas aeruginosa (PA) CSOM mouse model.<h4>Methods ...[more]

PMID: 36096817

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Project description:BackgroundChronic suppurative otitis media (CSOM) is a common otolaryngology disease, and cholesteatoma is the most aggressive type of CSOM. CSOM with and without cholesteatoma both result in a certain level of sensorineural damage, which can be categorized as air conduction (AC), bone conduction (BC), or air-bone gap (ABG), and AC, BC, and ABG are affected by many factors. Further analyses and comparisons of factors affecting sensorineural damage in CSOM with and without cholesteatoma were conducted in this study.MethodsA comparative study was conducted of 79 patients with CSOM (39 with cholesteatoma and 40 without cholesteatoma) whose diagnoses were mainly based on chronic middle ear infections and hearing loss (HL), typical computed tomography (CT) and surgical findings. Audiological evaluation included AC, BC and ABG, and sensorineural damage was defined as mixed and sensorineural HL (SNHL).ResultsIn relation to the types of HL, there were no significant differences between both groups. The CSOM with cholesteatoma group had significantly greater AC (P=0.000) and a significantly greater ABG (P>0.05) than the CSOM without cholesteatoma group, but BC did not differ significantly between both groups (P>0.05). The average AC-middle frequency (MF), AC-high frequency (HF), ABG-MF and ABG-HF of CSOM without cholesteatoma were smaller than these of CSOM with cholesteatoma (P<0.05). The degree of HL differed significantly between both groups (P=0.000). The CSOM with cholesteatoma group showed a higher level of HL than the CSOM without cholesteatoma group. The presence of cholesteatoma was presented a protective factor associated with sensorineural damage (P<0.05), while higher degrees of hearing and aging were risk factors (P<0.05), respectively.ConclusionsOur direct comparisons showed that HL progressed more rapidly in the CSOM with cholesteatoma group, which had higher frequencies in relation to AC, the ABG, and severity. However, in relation to BC, there were no significant differences between both groups, which was in line with the similar proportions of the types of HL in both groups. The logistic regression showed that the presence of cholesteatoma was a protective factor, and the degree of hearing and aging were risk factors associated with sensorineural damage.

Project description:BackgroundChronic suppurative otitis media (CSOM) is an important cause of hearing loss in children and constitutes a serious health problem globally with a strong association to resource-limited living conditions. Topical antibiotics combined with aural toilet is the first-hand treatment for CSOM but antimicrobial resistance and limited availability to antibiotics are obstacles in some areas. The goal of this study was to define aerobic pathogens associated with CSOM in Angola with the overall aim to provide a background for local treatment recommendations.MethodsSamples from ear discharge and the nasopharynx were collected and cultured from 152 patients with ear discharge and perforation of the tympanic membrane. Identification of bacterial species was performed with matrix-assisted laser desorption/ionization-time of flight mass spectrometry and pneumococci were serotyped using multiplex polymerase chain reactions. Antimicrobial susceptibility testing was done according to EUCAST.ResultsOne hundred eighty-four samples from ear discharge and 151 nasopharyngeal swabs were collected and yielded 534 and 289 individual isolates, respectively. In all patients, correspondence rate of isolates from 2 ears in patients with bilateral disease was 27.3% and 9.3% comparing isolates from the nasopharynx and ear discharge, respectively. Proteus spp. (14.7%), Pseudomonas aeruginosa (13.2%) and Enterococcus spp. (8.8%) were dominating pathogens isolated from ear discharge. A large part of the remaining species belonged to Enterobacteriaceae (23.5%). Pneumococci and Staphylococcus aureus were detected in approximately 10% of nasopharyngeal samples. Resistance rates to quinolones exceeded 10% among Enterobacteriaceae and was 30.8% in S. aureus, whereas 6.3% of P. aeruginosa were resistant.ConclusionsThe infection of the middle ear in CSOM is highly polymicrobial, and isolates found in nasopharynx do not correspond well with those found in ear discharge. Pathogens associated with CSOM in Angola are dominated by gram-negatives including Enterobacteriaceae and P. aeruginosa, while gram-positive enterococci also are common. Based on the results of antimicrobial susceptibility testing topical quinolones would be the preferred antibiotic therapy of CSOM in Angola. Topical antiseptics such as aluminium acetate, acetic acid or boric acid, however, may be more feasible options due to a possibly emerging antimicrobial resistance.

Dataset Information

Chronic suppurative otitis media causes macrophage-associated sensorineural hearing loss.

Background

Methods

Results

Conclusions

Publications

Chronic suppurative otitis media causes macrophage-associated sensorineural hearing loss.

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