STUDY OF RESISTENCE PHENOTYPES AND GENOTYPES IN STREPTOCOCCUS AGALACTIAE ISOLATED FROM NEONATES AND ADULTS WITH INVASIVE INFECTIONS IN ARGENTINA.

MARINA NOVOSAK; FERNANDO BOBADILLA; ILIANA JULIETA CORTESE; MARGARITA LACZESKI

Valencia

Congreso; FEMS 2017, 7th Congress of European Microbiologist.; 2017

Federation of european microbiological societies

BackgroundsStreptococcus agalactiae (GBS) is responsible for severe invasive infections in neonates and adultswith or without underlying chronic diseases. Penicillin is the drug of election for treatment, however, inallergic to β-lactams patients, erythromycin (ERI) and clindamycin (CLI) are the recommended drugs.In the last years, increased macrolide resistance has been reported. Mechanisms include changes intarget site mediated by erm genes leading to resistance to macrolide-lincosamides-streptogramin B(MLSB - phenotype expressed in inducible or constitutive form) or mechanisms by efflux encoded bymef genes leading to macrolide resistance of 14-15 members (M phenotype). The knowledge of thesephenotypes allows to adapt the treatment.ObjectivesThe objective was to study the mechanisms of resistance to ERI and CLI in GBS recovered frompatients with invasive diseases.MethodsTwenty six strains isolated from blood cultures and cerebrospinal liquid from neonates and adultswere investigated. MLSB resistance phenotypes was determined by the double-disc test (D-Test) andermB and mefA genes by PCR technique.Two GBS strains (7.69%) presented resistancephenotypes, one constitutive MLSB phenotype and the other M phenotype. The presence of ermB andmefA genes was demostrated by PCR. This showed a correlation between the phenotype andgenotype detected.ConclusionsThe results indicate the importance of D-Test technique for monitoring of the resistance to theseantibiotics and to implement treatment strategies. In addition, these results confirm the presence ofassociated genes that can be transmitted between bacteria and disseminate the mechanisms ofresistance involved.