RESUMO
The aim of this study was to investigate the existence of a ß-lactamase gene in a group of multi-drug resistant Acinetobacter baumannii. Twenty strains of multi-drug resistant A. baumannii were isolated. Thirty-four ß-lactamase genes and the ISaba1-OXA-23 linkage were analyzed in these strains by polymerase chain reaction (PCR) and verified by DNA sequencing. Three kinds of ß-lactamase genes (TEM, ADC, and OXA-23) were identified, among which the sequence of strain No. 20, ADC, was different from ADC subtypes recorded by GenBank, and was identified as a new variant of ß-lactamase genes (named ADC-61 and registered in GenBank: accession No. JQ753702); all the other 19 strains were ADC-30. Eighteen strains of the OXA-23 group were all positive as indicated by detection of ISaba1-OXA-23 linkage. Gene sequencing indicated that the TEM gene was TEM-1. These results suggest that the three kinds of ß-lactamase genes identified in this study, TEM, ADC, and OXA-23, play a key role in drug resistance in this group of A. baumannii. To our knowledge, this is the first report of an emergent new mutation of the ß-lactamase gene, ADC-61, in China or abroad.
Assuntos
Acinetobacter baumannii/genética , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla/genética , beta-Lactamases/genética , Infecções por Acinetobacter/epidemiologia , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/classificação , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Antibacterianos/farmacologia , Sequência de Bases , China/epidemiologia , Expressão Gênica , Humanos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA , beta-Lactamases/metabolismoRESUMO
A total of 18 families with multiple cases of breast cancer were identified from southern Taiwan, and 5 of these families were found to carry cancer-associated germline mutations in the BRCA1 and BRCA2 genes. One novel cryptic splicing mutation of the BRCA1 gene, found in two unrelated families, was shown to be a deletion of 10 bp near the branch site in intron 7. This mutation causes an insertion of 59 nucleotides derived from intron 7 and results in a frameshift, leading to premature translational termination of BRCA1 mRNA in exon 8. Deletions of 2670delC, 3073delT and 6696-7delTC in the BRCA2 gene were found in three other breast cancer families. All three deletions are predicted to generate frameshifts and to result in the premature termination of BRCA2 protein translation. Several genetic polymorphisms in both BRCA1 and BRCA2 genes were also detected in this investigation.