Outbreak of Brucella melitensis infection in Eastern Sicily: risk factors, clinical characteristics and complication rate.

Brucellosis is one of the most common zoonoses in the world, especially in Southern Italy, where many cases are still recorded every year. 128 cases of brucellosis were observed in Messina (Sicily) in 2016, representing a tenfold increase in the number of cases of brucellosis expected. The aim of this multicenter retrospective study was to analyze clinical and microbiological aspects of a brucellosis outbreak in the province of Messina in 2016, the incidence of its complications and the treatment combinations applied. The principal transmission route was through the ingestion of unpasteurized fresh cheese. The mean latency period between the onset of the symptoms and diagnosis was 35.58 ± 42.75 days. A late diagnosis increases the risk of developing complications. Drug-resistant strains of B. melitensis to Trimethoprim/Sulfamethoxazole and Ciprofloxacin were found in blood cultures of 58.4% patients. Brucellosis is still present in Sicily. A diagnostic delay predisposes to complications requiring prolonged therapies. The finding of Brucella melitensis strains resistant to the most widespread treatments is worrisome and needs further investigation. Moreover, the use of alternative combination antibiotic therapy is recommended.