Epidemiology of acute bacterial pharyngitis in a general acute care hospital

Acute bacterial pharyngitis (ABP) accounts for 20 to 30% of acute pharyngitis. The most common bacterial agent is Streptococcus pyogenes. A retrospective, record-based study was carried out based on the microbiological records from 2010 to 2016, analyzing ABP's incidence, its causal agents and its incidence according to the season and age range. Erythromycin resistance and the main resistance phenotype were determined in S. pyogenes. Acute bacterial pharyngitis was diagnosed in 21.5% out of 3.246 cultures, 89% were due to S. pyogenes, 36.3% of patients were children between 7 to 10 years old and 31.3% were older than 15 years of age. There was a significant increase in pharyngitis due to Streptococcus dysgalactiae subsp. equisimilis since 2010 (p<0.05), 52.5% were detected in patients older than 15 years of age. There were only three cases of ABP produced by Arcanobacterium haemolyticum. A total of 36.1% of pharyngitis occurred during spring, with a significant increase during 2010 and 2016 springs. Global erythromycin resistance in S. pyogenes was 16.6% with predominance of the M phenotype. This resistance rate is higher than that described in other similar series, demonstrating the importance of continuously monitoring of macrolide R in S. pyogenes, since they are the antibiotics of choice to treat pharyngitis in patients allergic to penicillin.