〔Abstract〕 Abstract Objective To explore the molecular characteristics of four CAMP negative Streptococcus agalactiae (S. agalactiae) in whole genome sequencing. Methods The identification of suspicious bacterial strains was conduc- ted using matrix-assisted laser desorption ionization time-of-flight mass spectrometry ( MALDI-TOF MS) . For the strains confirmed as S. agalactiae through identification , further CAMP experiments were conducted . For CAMP negative strains , whole genome sequencing was performed using MGI DNBSEQ-T7 and MinION Flow Cell sequen- cing platforms . Subsequently , multi-locus sequence typing ( MLST) , virulence genes and resistance genes of the strains were compared and analyzed using various databases . Phoenix M50 fully automatic drug sensitivity analyzer was employed to determine the sensitivity of the bacterial strains to commonly used antibiotics . Results Four CAMP-negative S. agalactiae strains were included . Whole-genome sequencing analysis revealed that all four CAMP-negative S. agalactiae strains belonged to the ST862 type . These strains harbored 22 virulence genes associ- ated with capsular polysaccharides , β-hemolysin , and hyaluronidase , as well as seven resistance genes linked to macrolides , lincosamides , polypeptides , and aminoglycosides . Antimicrobial susceptibility testing revealed that CAMP-negative S. agalactiae was susceptible to penicillin G , cefepime , cefotaxime , and vancomycin . However , three strains exhibited resistance to erythromycin , and one strain demonstrated resistance to clindamycin . Conclu- sion Four CAMP negative S. agalactiae of the ST862 type possess multiple virulence and drug resistance genes , showing high resistance to erythromycin , warranting clinical attention .