Antibiotic therapy in necrotising external otitis: case series of 32 patients and review of the literature

Role of surgery along with antimicrobials in refractory skull base osteomyelitis-A prospective observational study

INTRODUCTION

Study aimed to ole of surgery along with antimicrobials to improve clinical outcomes in treating refractory cases of skull base osteomyelitis (SBO).

METHODS

A prospective observational study in a tertiary care centre with 70 SBO patients meeting eligibility criteria. The study population comprised 35 patients refractory to systemic antimicrobials of at least 4 weeks duration who later underwent surgery in addition to medication (surgical group). They were compared with a medical group that responded to medications alone. The outcome variables studied were the resolution of clinical features (pain, discharge, radiology, and inflammatory markers), culture yield, and total duration of treatment.

RESULTS

According to our study, relief of pain was faster in the surgical group (1.66 against 4.57 months) with statistical significance (p < 0.001). Relief of symptoms (p < 0.001), radiological improvement (p = 0.001), and normalising of inflammatory markers (p < 0.001) were better in the surgical group than in the medical group. The duration of treatment was an average of 9.2 months in the surgical group compared to 11.3 months in the medical group (p = 0.019). Microbial culture from deep tissue sampling was positive in 24 surgical patients (68.57%).

CONCLUSIONS

The treatment response in selected patients of refractory SBO who underwent surgery along with antimicrobials was better than the group who responded to antimicrobials alone. Surgery provided higher microbial yield resulting in culture-specific antimicrobials. The surgical group observed faster relief of symptoms, reduced hospital stay, and total treatment duration.

Clinical outcomes in OPAT patients treated with ceftriaxone 4 g and ceftazidime 6 g extended interval dosing regimens

Background

New dosing regimens for ceftriaxone 4 g/24 hours and ceftazidime 3 g/12 hours are convenient for patients receiving OPAT. To date, these have not been clinically validated.

Aim

To assess the tolerability, toxicity and effectiveness of once daily ceftriaxone (4 g) and 12 hourly ceftazidime regimens (3 g twice a day) in the OPAT setting.

Patients and methods

From April 2018 until March 2023; demographic, clinical, microbiological and outcome data were collected on all adult patients discharged to a community-based OPAT team in East London.

Results

There were 487 OPAT episodes. Fifty-three (10.9%) patients received ceftriaxone 4 g once a day and 20 (4.1%) ceftazidime 3 g twice a day. In the ceftriaxone group, the commonest conditions treated were orthopaedic, neurosurgical or diabetic foot infections. OPAT was used to expedite the discharge of 45 (84.9%) patients, the remainder were admission avoidance episodes. The commonest isolate causing infection was MSSA 23 (43.4%). There were no tolerability or toxicity episodes recorded. All patients were cured and bed days saved were 1266.In the smaller twice-daily ceftazidime cohort, seven (35%) patients were treated for necrotizing otitis externa, six (30%) for bronchiectasis and six (30%) for urinary tract infections. The commonest cause of infection was P. aeruginosa, 18 (90%). One case of nephrotoxicity was recorded. All patients were cured and bed days saved were 896.

Conclusions

Regimens of ceftriaxone 4 g once a day and ceftazidime 3 g twice a day were well tolerated and highly effective. If widely adopted, these regimens will save OPAT and nursing time and enable more patients to be treated.

Epidemiology and risk factors for extension of necrotizing otitis externa

PURPOSE

Necrotizing otitis externa (OEN) is an aggressive and morbid infection of the external acoustic meatus. What are the risk factors for OEN extension?

METHODS

French monocentric retrospective study (2004-2021), including patients with OEN defined by the association of an inflamed EAM, a positive nuclear imaging, the presence of a bacteriological sample and the failure of a well-followed local and/or general antibiotic treatment. OEN was extensive if it was associated with vascular or neurological deficits, if nuclear imaging fixation and/or bone lysis extended beyond the tympanic bone.

RESULTS

Our population (n = 39) was male (74%), type 2 diabetic (72%), aged 75.2 years and pseudomonas aeruginosa was found in 88% of cases. Complications for 43% of patients were extensive fixation on nuclear imaging, for 21% of them the presence of extensive bone lysis, for 13% the appearance of facial palsy, for 5.3% the presence hypoglossal nerve palsy and for 2.5% the presence of thrombophlebitis or other nerves palsies. 59% of our population had extensive OEN. The diagnosis of the extensive OEN was made 22 days later (p = 0.04). The clinical presentation was falsely reassuring due to easier identification of the tympanic membrane (70% vs 46%, p = 0.17) but associated with periauricular oedema (42% vs 0%), bone exposure (16% vs 0%) and a temporomandibular joint pain (41% vs 12%).

CONCLUSION

Delayed treatment of OEN, identification of clinical bone lysis, especially when the tympanic membrane is easily visualized, and the presence of unbalanced diabetes are potential risk factors for extension of OEN.

A systematic review of antimicrobial treatment regimens and their outcomes in necrotising otitis externa

BACKGROUND

Necrotising otitis externa is a serious infection with minimal evidence underpinning its management. This review aims to synthesise published evidence of antimicrobial therapies and their outcomes in necrotising otitis externa.

METHODS

The review was PROSPERO registered (CRD42022353244) and conducted according to Preferred Reporting Items for Systematic Review and Meta-Analyses ('PRISMA') guidelines. A robust search strategy filtered 28 manuscripts into the final review. Antimicrobial therapy and clinical outcome data were extracted and analysed.

RESULTS

Published studies are heterogeneous, with high risk of bias and low certainty. Reporting of outcomes is poor and extremely variable. First-line therapy is most commonly in-patient (95 per cent) empiric fluoroquinolone (68 per cent) delivered intravenously (82 per cent). The lack of granular data and poor outcome reporting mean it is impossible to correlate treatment strategies with clinical outcomes.

CONCLUSION

Robust, consistent outcome reporting with reference to treatments administered is mandatory, to inform clinical management and optimise future research. Optimal antimicrobial choices and treatment strategies require clarification through prospective clinical trials.

Management and Outcomes of Necrotizing Otitis Externa: A Retrospective Cohort Study in a Tertiary Referral Center

Objectives

Necrotizing otitis externa (NOE) is a rare infection of the ear that causes osteomyelitis. We aimed to evaluate treatment outcomes and the role of imaging in diagnosing and monitoring disease resolution in a single-center study of patients with NOE.

Methods

In this retrospective cohort study, patients with NOE who were diagnosed and treated in a tertiary otology center in Utrecht, The Netherlands, between January 1, 2013 and August 1, 2022, were included. Data were retrieved from the medical records on demographics, symptoms, physical and diagnostic findings, type and duration of treatment, and course of disease.

Results

A total of 24 cases were included. Patients were often elderly (mean age = 75 years) and diabetic (88%). Pseudomonas aeruginosa was the most commonly found microorganism (63%). Twenty-two cases (92%) received intravenous antibiotic treatment, and 7 cases (29%) received additional systemic antifungal treatment. The mean duration of systemic treatment was 29 weeks. In 20 out of 22 cases (91%), imaging was used to determine the end point of treatment. None of the cases with a total resolution of disease activity (n = 5) on 18F-fluorodeoxyglucose-positron emission tomography-computed tomography imaging at the time of cessation of therapy showed clinical relapse, compared with 1 out of 4 cases on gallium single-photon emission computerized tomography.

Conclusion

Based on the experience from our center, we demonstrated that patients with NOE can successfully be treated with prolonged systemic treatment. Molecular imaging is reasonably successful for disease evaluation and decision-making on the eradication of disease.

Patients' experience of necrotising otitis externa: a qualitative study

BACKGROUND

Necrotising otitis externa is a serious infective condition. Patients are typically frail, diagnostic delay is common and severe pain is a key feature. This study aimed to qualitatively analyse patient-centred data to identify key themes in the patient's experience.

METHODS

Open-ended questionnaires were sent to 28 patients. Responses were qualitatively analysed using a grounded theory approach. Iterative cycles were used to develop codes using a constant comparison technique. Emerging categories were refined to identify core themes.

RESULTS

Four main themes emerged: severe pain, mental health, quality of life and diagnostic delays.

CONCLUSION

This is the first study to explore patients' perspectives in necrotising otitis externa. It indicates a need to raise awareness of necrotising otitis externa, and to improve symptom management, pain control and quality of life. This valuable information can be used to identify research priorities, guide service improvements, improve clinical care and feed into the development of a Core Outcome Set for necrotising otitis externa.

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.

Necrotizing external otitis: analysis of relapse risk factors in 66 patients managed during a 12 year period

BACKGROUND

Necrotizing external otitis (NEO) is a severe infection of the skull base that occurs generally in the elderly and/or in diabetic recipients. There are few data in the literature about the therapeutic management of this complex bone infection.

OBJECTIVES

To analyse relapses after NEO treatment completion, and to describe the clinical features of NEO.

METHODS

We performed a retrospective cohort study in the Lyon regional reference centre for the management of complex bone and joint infections. Consecutive cases of NEO from 1 January 2006 to 31 December 2018 were included. The primary outcome was the relapse of NEO. Variables were analysed using Cox regression survival analysis with adjusted hazard ratio (aHR) and Kaplan-Meier curve.

RESULTS

Sixty-six patients were included. Median age was 75 (IQR 69-81) years and 46 (70%) patients were diabetic. Eleven patients (17%) had temporomandibular arthritis, 10 (15%) cranial nerve paralysis, 2 (3%) cerebral thrombophlebitis, and 2 (3%) contiguous abscess. Microbiological documentation was obtained in 56 patients and revealed Pseudomonas aeruginosa in 44/56 patients (79%). Nine (14%) cases had no microbiological documentation. Antibiotic therapy was dual for 63 (95%) patients. During a median follow-up of 27 (IQR 12-40) months, 16 out of 63 (25%) patients experienced a relapse. Fungal infection was significantly associated with relapse [aHR 4.1 (95% CI 1.1-15); P = 0.03].

CONCLUSIONS

NEO is a severe bone infection, mainly (but not exclusively) caused by P. aeruginosa, which occurs in elderly and diabetic recipients. Fungal infections at baseline significantly impact the outcome.

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.

Type 3 secretion system of Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen, mainly affecting severe patients, such as those in intensive care units (ICUs). High levels of antibiotic resistance and a long battery of virulence factors characterise this pathogen. Among virulence factors, the T3SS (Type 3 Secretion Systems) are especially relevant, being one of the most important virulence factors in P. aeruginosa. T3SS are a complex "molecular syringe" able to inject different effectors in host cells, subverting cell machinery influencing immune responses, and increasing bacterial survival rates. While T3SS have been largely studied and the molecular structure and main effector functions have been established, a series of questions and further points remain to be clarified or established. The key role of T3SS in P. aeruginosa virulence has resulted in the search for T3SS-targeting molecules able to impair their functions and subsequently improve patient outcomes. This review aims to summarise the most relevant features of the P. aeruginosa T3SS.

Calculated parenteral initial treatment of bacterial infections: Infections in the ear, nose, throat and mouth and jaw area

This is the sixth chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. The chapter deals with the antibacterial treatment of more severe infections of the ear, the nose, the throat and the maxillofacial region, including odontogenic and salivary gland infections.

Malignant otitis externa, an increasing burden in the twenty-first century: review of cases in a UK teaching hospital, with a proposed algorithm for diagnosis and management

Background

Malignant otitis externa is a potentially fatal infection of the skull base. With an ageing population and increasing prevalence of diabetes, the incidence of malignant otitis externa in the British population is rising. To date, there remain no accepted diagnostic criteria, few prognostic indicators and no consensus treatment pathways.

Method

A prospective case series was conducted at a tertiary referral teaching hospital.

Results

A cohort of susceptible individuals predominates (elderly, male, with immunosuppression and diabetes), with 25 per cent reporting a preceding incident. Otorrhoea, otalgia and canal granulation were the commonest presenting features, alongside positive pseudomonas cultures. No clear markers for predicating disease severity were isolated; however, a high initial haemoglobin A1c level demonstrated a significant moderately positive correlation with length of treatment.

Conclusion

A treatment pathway designed to provide a standardised approach to investigation and treatment is proposed, which aims to increase earlier diagnosis, streamline care and facilitate the development of best practice.

Current management of necrotising otitis externa in the UK: survey of 221 UK otolaryngologists

INTRODUCTION

Necrotising otitis externa (NOE) is a rare infection causing skull base osteomyelitis. The evidence regarding NOE consists mostly of case series. Hence, there is a limited evidence base to guide decision-making. This survey aims to report the experience of 221 otolaryngologists in this condition.

MATERIALS AND METHODS

Internet survey administered to the membership of the British Association of Otorhinolaryngology - Head and Neck Surgery (ENT UK).

RESULTS

Respondents' detailed replies on diagnosis, treatment and follow up are presented. One third of respondents reported increasing incidence of NOE. Over 80% diagnosed NOE based on pre-existing risk factors, severe pain, non-resolution of infection and CT scan. Most respondents managed NOE with intravenous antibiotics (90%) and blood sugar control (82%). There was less agreement in certain aspects of management including the role of surgery and the nature and duration of follow up.

CONCLUSIONS

Our survey provides a picture of NOE management in the UK. While there is consensus in some aspects of NOE management, other aspects attract widely differing answers. This may reflect the lack of strong evidence in the literature. Future work should aim to address this.