Acute Mastoiditis Associated with Pseudomonas Aeruginosa in the Pediatric Population of the Umbria Region, Italy

Acute mastoiditis (AM) is the most common complication of acute otitis media (AOM) and is one of the most severe acute bacterial diseases in infants and children. In some geographic areas, the incidence of AM is increasing, and the causative role of some bacterial pathogens could be greater than previously thought. In this paper, the results of a study that evaluated the epidemiology and microbial etiology of paediatric AM in Umbria, which is a region of central Italy, are reported. This is a retrospective study of patients aged 0-14 years with AM admitted to the pediatric wards of the hospitals of Umbria, Italy, between June 1 and September 30 in four consecutive years (2015-2018). A total of 108 children were enrolled. The prevalence of AM in males during the four years of analysis was significantly higher than that in females at 63% (95% confidence intervals [CI]: 0.54-0.72). The most frequently affected age groups were 5-9 years (45.4%) and 10-14 years (31.5%), with statistically significant differences in comparison with children aged <1 year (5.6%, 95% CI: 0.01-0.10) and 1-4 years (17.6%, 95% CI: 0.10-0.25). In most cases (64, 59.3%), AM was associated with spontaneous tympanic membrane perforation (STP). The culture of the middle ear fluid revealed the presence of Pseudomonas aeruginosa in 56 cases (51.6%). The mean incidence rates of pediatric AM in Umbria during the study increased significantly with time, as it was 18.18/100,000 children/year in 2015-2016 and 29.24/100,000 children/year in 2017-2018 (CI difference: +2.5 - +19.9, p < 0.05). The incidence rates of Pseudomonas aeruginosa detection in pediatric AM associated with STP significantly increased with time. The incidence was 6.06/100,000 children/year in 2015-2016 and 18.61/100,000 children/year in 2017-2018 (CI difference: +6.1 - +19.0, p < 0.001). This study demonstrated the high and increasing incidence of AM in the Umbria region during the summer months and the frequent detection of P. aeruginosa as an etiologic agent of the disease in the presence of STP. Confirmation of these results with a larger study population, in different settings, and throughout the whole year is needed to define the first-line approach of AM with STP in pediatrics.