Culture-negative necrotizing otitis externa: diagnosis and management

Abstract

Objective We aim to describe the clinical features and therapeutic management of necrotizing otitis externa (NOE) with negative culture. Patients and methods We included all patients with NOE, who were treated in the period between 2008 and 2020 in our department. Results A total of 25 cases of NOE were included. The result of the culture was negative in 13 cases (52%). All patients received a local treatment prior to hospitalization, and eight patients (61.5%) received oral antibiotic. A sampling of the otorrhea was done for all patients. Fungal serology was performed for six patients; it was positive in two cases. The prescribed first-line was ciprofloxacin in combination with ceftazidime for 10 patients, while it was based on the use of imipenem with ciprofloxacin for 2 patients and one patient only received ciprofloxacin. An improvement was noted in 10 cases (77%). The second-line treatment in the three cases of resistance was imipenem with ciprofloxacin in one case. For the two patients with a positive aspergillus serology, one patient received teicoplanin, fusidic acid, imipenem, and voriconazole and the other patient received voriconazole. The total duration of the treatment was a minimum of 6 weeks. An improvement was noted in all cases, and recurrence was noted in 3 cases. Conclusion In our study, there were no clinical or radiological specificities noted in NEO with negative culture. Sampling must be repeated. Fungal origin should be suspected in refractory forms and empiric antifungal treatment may be useful.

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

“…Notably, microbiological sampling techniques varied between studies and are discussed in several studies. Culture-negative cases of clinically and radiologically diagnosed necrotising otitis externa are well recognised, 20 and may be explained by prior antibiotic use, fungal necrotising otitis externa or inadequate sampling technique. 51 In culture-negative and non-resolving cases, deep tissue sampling is increasingly being used 52 to optimise antimicrobial therapy choices and strategies.…”

“…Chaabouni 20 High The Journal of Laryngology & Otology 125 intracellular efflux mechanisms that reduce antibiotic penetration, rendering it a challenge to eradicate. 16 Although challenging to attribute specific antimicrobial regimens due to heterogeneous reporting, it is clear from this review that the side effects of antimicrobial therapy are common and can be serious.…”