RESUMO
Macrolide antibiotics are recommended for the treatment of pneumococcal pneumonia and invasive pneumococcal disease (IPD). Prior to 2000, â¼10% of Streptococcus pneumoniae strains isolated from IPD cases in Latin American countries were resistant to macrolides. The mechanism of resistance to macrolides was associated mainly with the efflux pump known as the macrolide efflux genetic assembly, since most pneumococcal strains carried the mef(A/E) gene, whereas <6% strains carried both the methylase gene ermB and mef(A/E). In the first decade of this century, a significant increase in the prevalence of macrolide resistance was observed in pneumococcal strains in both Mexico and Peru. Approximately 30% of S. pneumoniae strains in these countries were already resistant to erythromycin, while the prevalence in Colombia, Argentina, and Brazil remained below 10%. During the last decade, we have been experiencing a worrisome increase in pneumococcal strains carrying resistance to macrolides, with a prevalence of up to 80% for resistance to erythromycin. The mechanism for disseminating macrolide resistance has evolved. Currently, more than 55% of invasive S. pneumoniae macrolide-resistant strains carry both the ermB and the mef(A/E)/mel genes. Lessons learned from the current macrolide resistance crisis in Latin America can inform interventions in other regions.
Assuntos
Antibacterianos , Farmacorresistência Bacteriana , Macrolídeos , Infecções Pneumocócicas , Streptococcus pneumoniae , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/genética , Macrolídeos/farmacologia , América Latina/epidemiologia , Antibacterianos/farmacologia , Humanos , Farmacorresistência Bacteriana/genética , Infecções Pneumocócicas/microbiologia , Infecções Pneumocócicas/epidemiologia , Infecções Pneumocócicas/tratamento farmacológico , Testes de Sensibilidade MicrobianaRESUMO
The genetic diversity of 47 clinical and reference strains of Candida glabrata from several geographical origins and diverse clinical disorders, with different antifungal susceptibilities, as well as their genetic relationships were studied through multilocus enzyme electrophoresis (MLEE) and randomly amplified polymorphic DNA (RAPD) techniques. The genetic diversity estimated for 11 MLEE loci measured as average heterozygosity (h) was 0.055. A high level of genetic relatedness among isolates was established by cluster analysis. Forty-nine RAPD markers were analyzed, and the average genetic diversity among isolates, estimated by Shannon's index (Ho), was 0.372. The PhiST values estimated through an analysis of molecular variance to assess genetic differentiation among isolates revealed no genetic differentiation among them. Our results revealed very low genetic diversity among isolates, a lack of differentiation, and no association with their geographic origin and the clinical characteristics.
Assuntos
Candida glabrata/classificação , Candidíase/microbiologia , Variação Genética , Antifúngicos/farmacologia , Candida glabrata/efeitos dos fármacos , Candida glabrata/genética , Candida glabrata/isolamento & purificação , Candidíase/fisiopatologia , Eletroforese em Gel de Amido/métodos , Enzimas/análise , Humanos , Testes de Sensibilidade Microbiana , Técnicas de Tipagem Micológica , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
Because Candida species have innately highly variable antifungal susceptibilities, the availability of a fast and reliable species identification test is very important so that suitable and effective therapeutic measures may be taken. Using three oligonucleotide primers, we established a randomly amplified polymorphic DNA (RAPD) analysis method that enabled direct identification of the most common opportunistic pathogenic Candida species. RAPD analysis revealed a characteristic molecular fingerprint for each Candida species. Differences between the profiles for Candida albicans and C. dubliniensis were evident. RAPD analysis is a relatively easy, reproducible, and reliable technique that can be useful in providing genetic fingerprints for the identification of strains. In addition, a collection of different C. albicans strains was identified by a specific PCR based on multiple secreted aspartic proteinase (SAP) genes and the dipeptidyl aminopeptidase (DAP2) gene. Our findings demonstrate that PCR based upon the SAP and DAP2 sequences is a simple, rapid, clear, and direct technique for the identification and differentiation of C. albicans and C. dubliniensis.