RESUMO
Two point mutations (A2074C and A2075G) in the 23S rRNA gene of Campylobacter coli and C. jejuni are associated with erythromycin resistance. A real-time fluorescence resonance energy transfer PCR assay using a melting curve analysis was developed to identify these two point mutations and the wild-type genotype in thermophilic Campylobacter species such as C. coli, C. jejuni, and C. lari. Concerning these species, 141 strains were tested and a result obtained in 140 (99.3%). A single genotype was detected in 133 cases and two genotypes in seven cases. There was an agreement with the phenotypic methods except for one C. coli strain that was not amplified during the PCR assay. The A2075G mutation was mainly found among the 92 resistant strains tested (95.6%) and the A2074C mutation only twice (2.2%). One C. jejuni strain (1.1%) harbored both mutations on the same 23S rDNA copy. When compared to the phenotypic tests, the new real-time PCR assay was able to detect the correct genotype, in all cases except one (1.1%). This assay is more sensitive and more rapid than other PCR assays, the entire procedure taking less than 2 hr.
Assuntos
Campylobacter coli/efeitos dos fármacos , Campylobacter jejuni/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Macrolídeos/farmacologia , Campylobacter coli/genética , Campylobacter jejuni/genética , Mutação , Reação em Cadeia da Polimerase , RNA Ribossômico 23S/genéticaRESUMO
Helicobacter pylori, a chronic gastric pathogen of human beings, can be divided into seven populations and subpopulations with distinct geographical distributions. These modern populations derive their gene pools from ancestral populations that arose in Africa, Central Asia, and East Asia. Subsequent spread can be attributed to human migratory fluxes such as the prehistoric colonization of Polynesia and the Americas, the neolithic introduction of farming to Europe, the Bantu expansion within Africa, and the slave trade.
Assuntos
Emigração e Imigração , Genética Populacional , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Polimorfismo Genético , África , Agricultura , América , Ásia , Proteínas de Bactérias/genética , Teorema de Bayes , Etnicidade , Europa (Continente) , Genes Bacterianos , Variação Genética , Geografia , Infecções por Helicobacter/transmissão , Helicobacter pylori/classificação , Helicobacter pylori/isolamento & purificação , Humanos , Indígenas Norte-Americanos , Idioma , Polinésia , Grupos Raciais , Recombinação Genética , Problemas Sociais , SoftwareRESUMO
A 23S rRNA gene fragment in domain V was sequenced from 30 clinical isolates of Campylobacter spp., including 22 resistant to macrolides. Two point mutations associated with erythromycin resistance were identified at positions 2074 and 2075 on the 23S rRNA gene (homologous to A2142C and A2143G mutations in Helicobacter pylori) in which an adenine residue is also replaced with a cytosine and a guanine residue, respectively. A combined PCR-restriction fragment length polymorphism technique was developed to detect these mutations by using the BsaI and BceAI enzymes.
