BACKGROUND: Scarce data are available about the antimicrobial resistance of Group A Streptococcus in South America. METHODS: This study evaluated the antimicrobial susceptibility profile of 1,112 isolates of Group A Streptococcus during the period from 1993 to 2009 in Curitiba city, Brazil. Macrolide-resistant isolates were characterized by emm typing and pulsed-field gel electrophoresis. RESULTS: All isolates were susceptible to penicillin, vancomycin, and tigecycline. On the contrary, 18.6% of the isolates were resistant to tetracycline, presenting a minimum inhibitory concentration (MIC)(50)/MIC(90) of 32/64 mg/L. Erythromycin resistance rose from 1.9% before 2000 to 4% after 2000 and was associated with a marked increased of MIC levels. Simultaneously, both the phenotype and genotype of macrolide resistance were modified as the M phenotypes (mef(A) genotype) were replaced by the cMLS(B) phenotypes (erm(B) genotype). CONCLUSION: This polyclonal spreading of cMLS(B) macrolide resistance has not been previously observed in South America and should stimulate further epidemiological surveillance in this part of the world.
BACKGROUND: Scarce data are available about the antimicrobial resistance of Group A Streptococcus in South America. METHODS: This study evaluated the antimicrobial susceptibility profile of 1,112 isolates of Group A Streptococcus during the period from 1993 to 2009 in Curitiba city, Brazil. Macrolide-resistant isolates were characterized by emm typing and pulsed-field gel electrophoresis. RESULTS: All isolates were susceptible to penicillin, vancomycin, and tigecycline. On the contrary, 18.6% of the isolates were resistant to tetracycline, presenting a minimum inhibitory concentration (MIC)(50)/MIC(90) of 32/64 mg/L. Erythromycin resistance rose from 1.9% before 2000 to 4% after 2000 and was associated with a marked increased of MIC levels. Simultaneously, both the phenotype and genotype of macrolide resistance were modified as the M phenotypes (mef(A) genotype) were replaced by the cMLS(B) phenotypes (erm(B) genotype). CONCLUSION: This polyclonal spreading of cMLS(B) macrolide resistance has not been previously observed in South America and should stimulate further epidemiological surveillance in this part of the world.
Authors: C-R Usein; L Grigore; R Georgescu; V Cristea; M Bãltoiu; M Strãuţ Journal: Eur J Clin Microbiol Infect Dis Date: 2012-02-23 Impact factor: 3.267
Authors: Ryan R McDonald; George R Golding; James Irvine; Morag R Graham; Shaun Tyler; Michael R Mulvey; Paul N Levett Journal: Genome Announc Date: 2013-06-27