Antibacterial effects of chitosan-based hydrogels containing Trachyspermum ammi essential oil on pathogens isolated from dogs with otitis externa.

BACKGROUND: Growing antibiotic resistance has made treating otitis externa (OE) increasingly challenging. On the other hand, local antimicrobial treatments, especially those that combine essential oils (EOs) with nanoparticles, tend to be preferred over systemic ones. It was investigated whether Ajwain (Trachyspermum ammi) EO, combined with chitosan nanoparticles modified by cholesterol, could inhibit the growth of bacterial pathogens isolated from OE cases in dogs. In total, 57 dogs with clinical signs of OE were examined and bacteriologically tested. Hydrogels of Chitosan were synthesized by self-assembly and investigated. EO was extracted (Clevenger machine), and its ingredients were checked (GC-MS analysis) and encapsulated in chitosan-cholesterol nanoparticles. Disc-diffusion and broth Micro-dilution (MIC and MBC) examined its antimicrobial and therapeutic properties. RESULTS: Staphylococcus pseudintermedius (49.3%) was the most common bacteria isolated from OE cases, followed by Pseudomonas aeruginosa (14.7%), Escherichia coli (13.3%), Streptococcus canis (9.3%), Corynebacterium auriscanis (6.7%), Klebsiella pneumoniae (2.7%), Proteus mirabilis (2.7%), and Bacillus cereus (1.3%). The investigation into the antimicrobial properties of Ajwain EO encapsulated in chitosan nanoparticles revealed that it exhibited a more pronounced antimicrobial effect against the pathogens responsible for OE. CONCLUSIONS: Using chitosan nanoparticles encapsulated with EO presents an effective treatment approach for dogs with OE that conventional antimicrobial treatments have not cured. This approach not only enhances antibacterial effects but also reduces the required dosage of antimicrobials, potentially preventing the emergence of antimicrobial resistance.

Chronic otorrhea and osteomyelitis of the external auditory canal by Achromobacter xylosoxidans: an uncommon diagnosis.

PURPOSE: Achromobacter xylosoxidans is an emerging pathogen mainly associated with resistant nosocomial infections. This bacteria had been isolated in the ear together with other pathogens in cultures from patients with chronic otitis media, but it had never been reported as a cause of osteomyelitis of the external auditory canal. CASE PRESENTATION: We present a unique case of a healthy 81-year-old woman who presented with left chronic otorrhea refractory to topical and oral antibiotic treatment. Otomicroscopy revealed an erythematous and exudative external auditory canal (EAC) with scant otorrhea. The tympanic membrane was intact, but an area of bone remodeling with a small cavity anterior and inferior to the bony tympanic frame was observed. Otic culture isolated multi-drug-resistant A. xylosoxidans, only sensitive to meropenem and cotrimoxazole. Temporal bone computed tomography showed an excavation of the floor of the EAC compatible with osteomyelitis. Targeted antibiotherapy for 12 weeks was conducted, with subsequent resolution of symptoms and no progression of the bone erosion. CONCLUSIONS: Atypical pathogens such as A. xylosoxidans can be the cause of chronic otitis externa. Early diagnosis and specific antibiotherapy can prevent the development of further complications, such as osteomyelitis. In these cases, otic cultures play an essential role to identify the causal germ. This is the first case of EAC osteomyelitis due to A. xylosoxidans reported to date.

A pilot study of antimicrobial effects and ototoxicity of a Norway spruce (Picea abies) resin-based canine otic rinse product.

BACKGROUND: Norway spruce (Picea abies) resin-based products are used in human medicine. A resin-based otic rinse also could be useful in supportive care of canine otitis externa (COE), yet information on its antimicrobial effect against canine pathogens or ototoxicity is lacking. OBJECTIVES: To investigate the antimicrobial properties and ototoxicity of a commercial resin-based otic product. MATERIALS AND METHODS: Antimicrobial effect was evaluated using a standardised challenge test on Staphylococcus pseudintermedius, Corynebacterium auriscanis, Pseudomonas aeruginosa, Escherichia coli, Malassezia pachydermatis, and Streptococcus halichoeri strains to measure reduction in growth after 24 h exposure to the product. Effect on cell morphology was investigated by exposing S. pseudintermedius, C. auriscanis, P. aeruginosa and M. pachydermatis to the product in 20% and 100% (v/v) concentrations for 6, 24 and 48 h, and evaluating cells by transmission (TEM) and scanning (SEM) electron microscopy. An in vitro microbial kill-rate assay also was performed. Auditory brain stem response test, clinical evaluation and postmortem histological evaluation of ear canals were undertaken on experimental guinea pigs treated with the test product or saline controls. RESULTS: The product showed >log 5 growth reduction for all strains in the challenge test. TEM and SEM images showed clear changes in the cells' inner structures and deterioration of cells, and 100% (v/v) test product exposure induced microbial killing in 1-2 h. Ototoxicity was not detected in guinea pigs. CONCLUSIONS AND CLINICAL RELEVANCE: The product may be an option in supportive care of COE because of antimicrobial effects and lack of ototoxic properties in a guinea pig model.

Predictive role of facial nerve palsy improvement in malignant external otitis.

PURPOSE: To evaluate the effects of different factors on facial nerve palsy improvement in patients with malignant external otitis (MEO) and the predictive role of improvement on MEO. METHODS: Data were collected from all MEO patients with facial paralysis who were hospitalized between 2012 and 2017 at a tertiary referral center. We contacted patients at least 6 months after their admission to evaluate their facial nerve function and survival rate. RESULTS: In a study of 19 samples with a mean age of 69.1 years, 9 patients (47.7%) had some or complete improvement, while 10 (52.6%) had no or very minimal improvement. In this study, there was no statistically significant difference between patients with and without facial nerve palsy improvement in terms of age, sex, usage of antifungal treatment alongside antibiotics, duration of hospital stays, HbA1c level, presentation of hearing loss and vertigo, the severity of facial palsy, comorbidity score, mean of fasting blood sugar, leukocytosis, first ESR and ESR drop, CRP and physiotherapy. We found a positive correlation between improving facial palsy and patients' survival rates. CONCLUSION: Considering the possible influence of facial paralysis improvement prognosis on MEO patients' survival, it could affect our approach to the disease.

Necrotizing external otitis: diagnostic clues in the emergency department.

PURPOSE: The assessment of necrotizing external otitis requires a high index of suspicion by the attending physician. The purpose of the study is to determine the accuracy of parameters available at the Emergency Department for the diagnosis of this pathology. METHODS: Retrospective diagnostic accuracy study. Patients consulting at the Emergency Department for longstanding ear swelling, severe otalgia, and failure to respond to topical treatment were included. Otoscopy, physical examination, CT appearance, and analytical results were tested for the diagnosis of necrotizing external otitis, using nuclear imaging as gold standard. Sensitivity, specificity, likelihood ratios and ROC curves were calculated. RESULTS: 24 patients were included; 13 cases were necrotizing external otitis, and 11 cases were other external ear pathologies. Erythrocyte sedimentation rate and C-reactive protein levels were significantly associated with necrotizing external otitis (AUC 0.92 p < 0.001, and 0.8 p < 0.001). Positive likelihood ratios were 10.15 for values of erythrocyte sedimentation rate over 26 mm/h, and 8.25 for C-reactive protein levels over 10 mg/L. Negative likelihood ratios were 0.08 and 0.28, respectively. These results were significant. The rest of clinical and radiological parameters were less accurate. CONCLUSIONS: Erythrocyte sedimentation rate and C-reactive protein are useful parameters in the evaluation of a case of longstanding otitis with clinical suspicion of necrotizing external otitis. If any of them is elevated, the probability of suffering this condition is significantly increased. If they are within normal ranges, an alternative diagnosis should be sought.

Lateral ear canal resection and bulla osteotomy with marsupialization to treat otitis media in rabbits: forty-eight procedures.

OBJECTIVE: Describe lateral ear canal resection and bulla osteotomy with marsupialization (LECARBOM) in rabbits with otitis media (OM), and report outcomes, complications, bacteria cultured from middle ears, and their antimicrobial susceptibility testing (AST) results. STUDY DESIGN: Retrospective clinical case series; single referral hospital. ANIMALS: Forty-two rabbits with naturally occurring OM. METHODS: Medical records (2011-2021) of rabbits with CT-confirmed OM undergoing surgery were reviewed for outcomes, complications, bacteria cultured from middle ears, and AST. RESULTS: Surgery was performed on 48 ears, and outcomes determined 21 days postoperatively. All rabbits survived the procedure. Otitis externa resolved in all lop-eared rabbits. Of 29 ears with OM-associated head tilt, eight (28%) resolved, nine (31%) improved, seven (24%) remained unchanged and five (17%) worsened. Outcome was not associated with head tilt duration nor OM severity. Postoperative complications occurred in 12 (25%) cases, seven of which had wound margin dehiscence that healed by 21 days. The most frequent bacteria isolated were Pasteurella multocida (16%), Bordetella bronchiseptica (14%) and Staphylococcus aureus (14%). Bacteria were sensitive to azithromycin, marbofloxacin or enrofloxacin and resistant to penicillin. CONCLUSION: LECARBOM is a well-tolerated surgical procedure to treat OM. It also improved or stabilized 83% of cases with head tilt and resolved all cases with otitis externa. CLINICAL SIGNIFICANCE: LECARBOM with administration of an AST-sensitive antibiotic, or azithromycin when no AST is performed, should be effective in rabbits with OM. Postsurgically, it resolves or alleviates most secondary conditions such as otitis externa, head tilt and facial nerve paralysis.

Antibiotics versus non-antibiotic treatments for acute otitis externa: A systematic review and meta-analysis.

BACKGROUND: Otitis externa is a condition causing inflammation of the outer ear canal, which presents with itching, discharge and pain. Most cases of acute otitis externa are caused by bacterial infection and are thus treated with antibiotics. This systematic review and meta-analysis of randomised controlled trials aims to assess the effectiveness of topical non-antibiotic treatments compared to topical antibiotic treatment for the treatment of acute otitis externa. METHODS: Systematic review and meta-analysis databases searched: Cochrane Library including ClinicalTrials.gov; MEDLINE; World Health Organisation International Clinical Trials Registry Platform and Web of Science to identify randomised clinical trials evaluating topical antibiotics and topical non-antibiotic agents in adults and children with acute otitis externa. Non-antibiotic therapeutics for comparison with topical antibiotics included antiseptics, steroids, non-pharmaceuticals and astringents. RESULTS: Seventeen trials were eligible for inclusion, with 10 combined in meta-analysis. Data could be pooled comparing antiseptic and steroid monotherapies with topical antibiotic agents. There were no significant differences in cure rates in any pairwise comparisons. Individually, the majority of studies favoured topical antiseptics or steroids over antibiotics, however these differences were not significant when pooled in meta-analysis. CONCLUSION: Antiseptic, steroid and antibiotic monotherapies are all effective for the management of acute otitis externa. There is insufficient evidence to suggest that topical antiseptic or steroid agents are superior or inferior to topical antibiotics.

Radiotherapy-induced Pathology of the Ear.

Acute radiotherapy (RT)-induced external ear soft tissue changes start with erythema and dry desquamation and may progress to moist desquamation and epidermal ulceration. Chronic RT-induced changes include epithelial atrophy and subcutaneous fibrosis. Although RT-induced radiation dermatitis has been well studied, interventions for soft tissue disease involving the external auditory canal (EAC) warrant investigation. Medical management includes topical steroid treatment for EAC radiation dermatitis and topical antibiotic therapy for suppurative otitis externa. Hyperbaric oxygen and pentoxifylline-vitamin E therapy have shown promise for other applications, but their clinical effect on soft tissue EAC disease is currently undefined.

Multiresistant Acinetobacter baumannii causing malignant otitis externa: a case report.

Abstract: Malignant otitis externa is an infection of the skin and soft tissue of the ear canal, spreading to the nearby structures. It causes severe otalgia and otorrhea, and can lead to ominous consequences such as cranial nerve damage and meningitis. The main etiologic agent is Pseudomonas aeruginosa and treatment relies on broad-spectrum intravenous antibiotics. We report a rare case of a woman suffering from Malignant otitis externa caused by Acinetobacter baumannii and requiring the use of colistin.

Changes in antimicrobial resistance in acute otitis media and otitis externa.

OBJECTIVES: Acute otitis media (AOM) and otitis externa (OE) are common ear infections which may warrant antibiotic therapy. For many infections, there is a rise in antimicrobial resistance, which is associated with treatment failure, morbidity, prolonged hospitalisation and mortality. This study aimed to identify longitudinal changes in microbiology and antimicrobial resistance in aural swabs taken from patients with AOM or OE. DESIGN: Retrospective observational analysis. SETTING: Aural samples processed at Manchester Medical Microbiology Partnership Laboratories between January 2008 and December 2018 were analysed to record organism isolated and antimicrobial sensitivity. PARTICIPANTS: Individual aural swabs from 7200 patients. MAIN OUTCOME MEASURES: Changes in the incidence of organisms and antimicrobial resistance between two time periods (2008-2012 and 2013-2018) were compared using the chi-squared test (alpha = 0.05). RESULTS: From 7200 swabs, 2879 (40%) were from children. The most frequently isolated organisms were Staphylococcus aureus (25%), Pseudomonas aeruginosa (24.4%), yeast (9.1%), mixed anaerobes (7.9%) and Haemophilus influenzae (6.1%). In children aged 0-4 years, H. influenzae had particularly high incidence (25%). Overall, the incidence of P. aeruginosa decreased significantly with time (p = 0.05). Isolates displaying resistance to one or more antimicrobial agents increased significantly in number in the second time period for P. aeruginosa (p = 0.04) and H. influenzae (p = 0.03). There was increased resistance to amoxicillin for P. aeruginosa (p = 0.01) and to erythromycin for H. influenzae (p < 0.01). CONCLUSION: Variations in type and frequency of organisms with increasing age likely result from differences in the preponderance of AOM compared to OE in children versus adults. We found increasing antimicrobial resistance for two organisms commonly isolated from AOM and OE infections, suggesting that aspects of current UK treatment practices and national recommendations may need to be revised.

Predictive factors in treatment response of malignant external otitis.

PURPOSE: To evaluate the prevalence and impact of various predictive factors including diabetes control in malignant external otitis (MEO) treatment response. METHODS: In a cross-sectional study on MEO patients, we defined treatment response with three indices; ESR level decrease, hospitalization period, and systemic antifungal drug usage. The impact of diabetes control and other predictive factors on these indices have been evaluated. RESULTS: Overall, 164 patients with a mean age of 67.8 ± 9.7 years were included. Cranial nerve involvement was present in 56 patients. Nine patients had immunodeficiency. 19.5% of cases had leukocytosis. Diabetes mellitus was present in 156 patients, suffering for an average of 13.9 ± 8.6 years. The overall mean hemoglobin A1C (HbA1c) level was 8.3% (4.4-12.8%), and the mean fasting blood sugar was 146.4 mg/dl (63-292 mg/dl). 29.3% of patients had good diabetes control before admission (HbA1c < 7%), 54.9% had poor control (7% < HbA1c < 10%) and 15.9% had very poor glycemic control (HbA1c > 10%). The predictive role for the following factors were not statistically significant: age, gender, comorbidities, diabetes, diabetes management method used before and during hospitalization, diabetes duration, leukocytosis, immunodeficiency, fasting blood sugar level, HbA1c level, glycemic control index, and insulin amount. However, CRP level with a mean value of 34.3 mg/L showed a significant correlation with ESR decrease, hospitalization period, and antifungal drug usage. CONCLUSION: CRP level could be used as a predictor for the hospitalization period, the need for systemic antifungal and ESR level decrease. It would be helpful to check the CRP level at the time of diagnosis to predict the hospitalization period and the necessity of systemic antifungal management to adjust the treatment strategy.

A retrospective study of 43 cases of fungal malignant external otitis.

Malignant external otitis (MEO) has a frequent bacterial origin, but we are currently witnessing the emergence of fungal agents, which poses difficulties in diagnosis and management. The aim of our work is to analyze the epidemiological and clinical profile of fungal MEO and to study the antifungal susceptibility of fungi involved. Our study is retrospective collecting 43 patients treated for fungal MEO between 2010 and 2019. Clinical, biological, and radiological data were collected from patient hospitalization records. Identification of yeasts was done by YST vitek®2 card. The antifungal susceptibility testing was performed for yeasts by the AST vitek®2 card and for other fungi by the E-test technique. The average age was 66 (± 12) years. We noted a male predominance in 63 % (n=27). Diabetes was found in 86%. Otalgia was a constant symptom. Cranial nerve palsies were observed in 16% (n=7) of cases. CT showed bone lysis in 74% (n=31>) of cases and Tc99 bone scintigraphy revealed hyperfixation in 100% (n=43) of cases. Candida spp. (n=21), Aspergillus spp. (n=18), and Geotrichum capitatum (n=2) were isolated. No resistance to antifungals has been demonstrated for Candida yeasts. Geotrichum capitatum isolates were resistant to fluconazole and caspofungin. Aspergillus isolates were resistant to amphotericin B and caspofungin in 50% (n=9) and 72% (n=12) of cases, respectively. Our study proves the predominance of Candida yeasts and Aspergillus as the fungal agents involved in MOE. Mycological diagnosis allows the identification and antifungal susceptibility testing. Thus, it allows using of the appropriate antifungal treatment and improves the prognosis of the disease.

Retrospective analysis of outcomes of outpatient parenteral antimicrobial therapy (OPAT) for necrotising otitis externa.

Necrotising otitis externa (NOE) is an uncommon but life-threatening infection that requires prolonged systemic antimicrobial therapy. This study aims to identify factors associated with treatment response and outcome in patients with NOE treated through outpatient parenteral antimicrobial therapy (OPAT). We performed a retrospective analysis of patients with NOE treated over a 4-year period (January 2018-January 2022) at a tertiary referral hospital in Derbyshire, UK. We defined OPAT failure as unplanned readmission within 30 days of discontinuation of OPAT. Prolonged duration of therapy was defined as length of parenteral antimicrobial treatment of more than 8 weeks. A total of 46 cases of NOE were reviewed. OPAT failure and prolonged therapy were recorded in 9 (19.6%) and 23 (50.0%) episodes respectively. Facial nerve involvement (odds ratio [OR], 14.54; 95% confidence interval [CI], 2.76-76.60; p = 0.002), dementia (OR, 7.65; 95% CI, 1.23-47.46; p = 0.029), Charlson comorbidity score (OR, 1.41 per unit increase; 95% CI, 1.00-2.00; p = 0.049) and peak CRP level (OR, 1.03 per unit increase; 95% CI, 1.00-1.06; p = 0.027) were associated with increased risk of treatment failure. Facial nerve involvement (OR, 16.30; 95% CI, 2.60-102.31; p = 0.003) and peak CRP level (OR, 1.04; 95% CI, 1.01-1.07; p = 0.016) were also associated with an increased need for prolonged antimicrobial therapy. In addition, extent of disease (based on imaging findings) was linked to prolonged therapy (OR, 22.89; 95% CI, 3.62-144.76; p = 0.001). NOE could be effectively managed as outpatient via OPAT. However, vigorous antimicrobial treatment and close monitoring of patients with pre-existing comorbidities, facial nerve paralysis, extensive disease and markedly elevated inflammatory markers are essential to optimise clinical outcomes.

A Different Era for Malignant Otitis Externa: The Non-Diabetic and Non-Immunocompromised Patients.

BACKGROUND: Τo investigate the differences in regard to the clinical, laboratory, and imaging findings as well as the treatment course between diabetic and non-diabetic, non-immunocompromised patients with malignant otitis externa. METHODS: A total of 36 hospitalized patients diagnosed with malignant otitis externa between January 2011 and December 2020 were divided into 2 groups according to their medical history, blood glucose, and glycated hemoglobin levels. RESULTS: Thirty-two patients were diabetic (group A) and 4 were non-diabetic, non-immunocompromised (group B). Otalgia was present in all patients (100%), followed by otorrhoea (67%) and edema (64%). Polyps were present in 18 patients (50%). Pseudomonas aeruginosa was isolated in 16 out of 25 positive cultures (64%). Four patients of group A and none of group B underwent surgery. Five patients of group A and none of group B had at least 1 cranial nerve involvement. The mean age was 77.22 ± 8.17 for group A and 47.25 ± 3.59 for group B (P < .001). No statistical significance was observed in regards to major symptoms, inflammatory markers (white blood cell, C-reactive protein, and erythrocyte sedimentation rate), positive imaging, and microbiological findings between the 2 groups. The average days of hospitalization were 42.41 ± 31.06 for group A and 10.25 ± 2.63 for group B (P < .049). Four diabetic patients died. CONCLUSION: Non-diabetic, non-immunocompromised adult patients with malignant otitis externa had a better response to antibiotic therapy and a shorter length of hospitalization. A high clinical suspicion for malignant otitis externa should always raise in cases of otitis externa that fail to respond in a topic and/or oral antibiotic treatment for more than a week.

Characteristics, management and outcome of a large necrotising otitis externa case series: need for standardised case definition.

BACKGROUND: Necrotising otitis externa is a severe ear infection for which there are no established diagnostic or treatment guidelines. METHOD: This study described clinical characteristics, management and outcomes for patients managed as necrotising otitis externa cases at a UK tertiary referral centre. RESULTS: A total of 58 (63 per cent) patients were classified as definite necrotising otitis externa cases, 31 (34 per cent) as probable cases and 3 (3 per cent) as possible cases. Median duration of intravenous and oral antimicrobial therapy was 6.0 weeks (0.49-44.9 weeks). Six per cent of patients relapsed a median of 16.4 weeks (interquartile range, 23-121) after stopping antimicrobials. Twenty-eight per cent of cases had complex disease. These patients were older (p = 0.042), had a longer duration of symptoms prior to imaging (p < 0.0001) and higher C-reactive protein at diagnosis (p = 0.005). Despite longer courses of intravenous antimicrobials (23 vs 14 days; p = 0.032), complex cases were more likely to relapse (p = 0.016). CONCLUSION: A standardised case-definition of necrotising otitis externa is needed to optimise diagnosis, management and research.

Standardised treatment protocol for necrotizing otitis externa: retrospective case series and systematic literature review.

OBJECTIVES: There is currently no consensus on the most effective treatment protocol for necrotizing otitis externa (NOE). This article aims to produce a NOE treatment protocol from the literature and clinical experience. METHODS: A total of 26 case series from the literature were reviewed in combination with a retrospective case series of inpatients from Hull University Teaching Hospitals NHS Trust from 2013-2018. Over 5 years, 40 patients were identified, with only 29 being analysed due to unavailable or incomplete case notes. RESULTS: In the literature review, the most common bacterial species causing NOE was Pseudomonas aeruginosa. Resistance to ciprofloxacin was prevalent, however multidrug resistance was rare. Ciprofloxacin and ceftazidime were the most widely used antibiotics. No ceftazidime resistance was reported in the literature or in our cohort. The average age of the patients in our cohort was 80 years. Moreover, 62% had either diabetes mellitus or were immunosuppressed. One patient died directly due to NOE-related sepsis. Intravenous ceftazidime monotherapy was mostly used. The duration of treatment was 6-7 weeks, with no relapses documented. CONCLUSION: Ceftazidime monotherapy was an effective empirical treatment in our cohort, and a total duration of 6-7 weeks of antibiotics was sufficient. We have created a standardised treatment protocol based on our findings that will need to be validated in a larger cohort of patients.