Surveillance of infectious diseases caused by Streptococcus pyogenes in the territory of the city of Belgrade

Abstract

Streptococcus pyogenes is a species of Gram-positive bacteria that causes infections that may have clinical manifestations. It is the causative agent of many major human diseases, ranging from pharyngitis and mild superficial skin infections to life-threatening systemic diseases. Diseases caused by this pathogen can be successfully treated when diagnosed in a timely manner, as the organism is always sensitive to penicillin. Delayed treatment of this common childhood bacterial infection is associated with significant mortality and morbidity. The aim of this study was to analyze the epidemiological characteristics of the diseases caused by Streptococcus pyogenes in the territory of the city of Belgrade from 2013 to 2023. We conducted a descriptive analysis of registered cases of Scarlatina, Pharingitis streptococcica and Tonsillitis streptococcica i.e., Scarlet fever, Streptococcal Pharyngitis and Streptococcal Tonsillitis during the mentioned period. The highest average age-specific incidence rates were registered as follows: for scarlet fever in the age groups of 1-4 years - 4146.0/100,000 and 5-9 years - 3101.7/100,000, for streptococcal pharyngitis and streptococcal tonsillitis in the age groups of 5-9 years - 9141.6/100,000 i.e., 12,850.2/100,000, and 1-4 years - 8134.4/100,000 and 10,396.0/100,000 respectively. During the analysed period, the highest number of scarlet fever cases was recorded in the colder months of the year i.e., in the period January-May (53.4%) and November-December (23.6%). Streptococcal pharyngitis is diagnosed throughout the year, and the highest number of these cases were reported in November (10.1%), while the highest number of cases of streptococcal tonsillitis were recorded in December (9.9%) and June (9.7%). In the examined period, 137 outbreaks of streptococcal infections were reported in kindergartens with a total of 1,087 cases, which is an average of seven infected children per outbreak. Streptococcal Pharyngitis, Streptococcal Tonsillitis and Scarlet Fever are diseases that affect a large number of residents of the City of Belgrade, especially in pre-school institutions, where surveillance of these diseases should therefore be intensified.