Florindo C, Viegas S, Paulino A, Rodrigues E, Gomes JP, Borrego MJ
Molecular characterization and antimicrobial susceptibility profiles in Streptococcus agalactiae colonizing strains: association of erythromycin resistance with subtype III-1 genetic clone family. [JOURNAL ARTICLE]
Clin Microbiol Infect 2009 Nov 2.
Abstract Knowledge on Streptococcus agalactiae epidemiology in Portugal is limited. Therefore, we aimed to study the S. agalactiae carriage rate among Portuguese reproductive-aged women and the prevalence of antibiotic resistance and to perform the molecular characterization of the clinical isolates. S. agalactiae was recovered from 6.2% of 4269 women during 2005-2007, revealing the predominance of capsular genotypes III (35%), V (33%), Ia (16%) and II (10%). To our knowledge, this is the first report of S. agalactiae colonization rate in Portugal performed according to CDC guidelines. All isolates were susceptible to penicillin and vancomycin, whereas resistance to clindamycin and erythromycin was detected in 10% and 19% of isolates, respectively. For the latter, 53% displayed the constitutive MLS(B) phenotype (conferring high-level resistance to macrolides), 42% had the inducible MLS(B), and M phenotype accounted for 5% of isolates. erm methylase genes were exclusively associated with MLS(B) phenotype isolates, whereas the M phenotype was due to the presence of mefA. MLST analysis of the genetic relatedness among isolates presenting resistance to erythromycin demonstrated a novel association between erythromycin resistance and subtype III-1/ST-19 genetic clone family. In conclusion, considering the association of genetic lineages expressing type III capsule with macrolide resistance, and its relation with invasive infection, epidemiological surveillance of this genotype is crucial.
More from this journal |
