Bacterial infections are the most common cause of ear inflammation or otitis. These infections can vary the etiology of otitis based on factors such as age or clinical presentation. The poster presented at the conference assessed the etiology of ear infection through categories such as age, clinical entity and period of the year in order to allow an appropriate empirical treatment.

The study assessed 715 otic's exudates received from September 2021 until September 2022. MALDI-TOF MS and manual antibiogram or an antibiogram with VITEK® were used to identify the infections. This followed the breakpoints of EUCAST. Acute otitis media (AOM), external otitis (EO), otorrhoea and otalgia were the clinical syndromes studied in participants of age groups ≤2, ≤18, ≤60 and over 60 years. Positive exudate cultures were seen in 48% participants; the age group ≤18 years had the most positivity (32%). A different aetiology was seen in different age groups; Haemophylus influenzae (33.3%) was the most common pathogen in ≤2 years; Pseudomonas aeruginosa and Staphylococcus aureus were most common pathogens seen in age groups of ≤18 and ≤ 60. In age over 60 years, there was a significant increase in filamentous fungi (24%). Among the clinical syndromes, AOM was the most frequent clinical form (41.1%), followed by EO (24.9%) and otorrhea (10.7%). AOM had pathogens which were most commonly associated with respiratory infection; Turicella otitidis was most commonly associated with EO.  In all the ears’s disorders analysed, P. aeruginosa and S. aureus were the most commonly isolated pathogens. In addition, in the months of July and September acute diffuse otitis most often had P. aeruginosa as the isolated pathogen. 

The study concluded that there was a different prevalence (Figure 1) with respect to the agents and population groups affected by these infections. 

Figure 1: Prevalence of isolated microorganisms

Figure 2: Variation of pathogens during the year

European Congress of Clinical Microbiology and Infectious Disease 2023, 15th April -18th April 2023, Copenhagen, Denmark