Rising Clindamycin Resistance in Group A Streptococcus in an Irish Healthcare Institution

Group A streptococcus (GAS) can cause serious invasive disease in humans with a high mortality rate. An increase in GAS infections was reported in Ireland in 2022, and this increase has been sustained in 2023 and is paralleled by similar trends in Europe. Rising antimicrobial resistance is a global problem and presents significant challenges to clinicians treating GAS infection. There was a reported increase in clindamycin resistance in GAS isolates in Ireland in 2022. We examined antimicrobial susceptibility patterns of GAS isolates in our institution in 2022. Although all GAS isolates included in our study were susceptible to penicillin, we noted a high clindamycin resistance rate of 28% in our invasive GAS isolates. We also noted high tetracycline and erythromycin resistance, 43% and 30%, respectively. Our results could have implications for empiric antimicrobial prescribing guidelines for skin and soft tissue infections, which often include clindamycin as it inhibits the production of many virulence factors associated with GAS. In addition, macrolides are often the first line recommended antibiotic for patients with anaphylaxis to penicillin. This study emphasises the importance of continuous surveillance and antimicrobial susceptibility testing of invasive and non-invasive isolates in order to monitor trends in increasing antimicrobial resistance.