Genomic characterization and resistance features of Streptococcus agalactiae isolated from non-pregnant adults in Shandong, China

While S. agalactiae strains in non-pregnant adults retain sensitivity to β-lactam antibiotics, the elevated resistance to erythromycin, clindamycin, levofloxacin and tetracycline is concerning. Given the growing elderly population worldwide, the burden of S. agalactiae infections is significant. Continuous surveillance of serotype distribution and antibiotic resistance patterns is imperative for targeted prevention and therapeutic strategies.