Data/hora: 01/06/2024 08:06:25

Provedor de dados: 	74	
País: 	Brazil	
Título: 	Environmental and genetic factors affecting mutability to aminoglycoside antibiotics among Escherichia coli K12 strains	
Autores: 	Monteiro,A.C.M.; Ferreira,R.C.C; Padilla,G.; Ferreira,L.C.S.; Costa,S.O.P.	
Data: 	2003-01-01	
Ano: 	2003	
Palavras-chave: 	Antibiotic resistance; Aminoglycosides; Escherichia coli K12; Mutator strains; Spontaneous mutantion frequencies.	
Resumo: 	Environmental and genetic factors affecting the in vitro spontaneous mutation frequencies to aminoglycoside resistance in Escherichia coli K12 were investigated. Spontaneous mutation frequencies to kanamycin resistance were at least 100 fold higher on modified Luria agar (L2) plates, when compared to results obtained in experiments carried out with Nutrient agar (NA) plates. In contrast to rifampincin, the increased mutability to kanamycin resistance could not be attributed to a mutator phenotype expressed by DNA repair defective strains. Kanamycin mutant selection windows and mutant preventive concentrations on L2 plates were at least fourfold higher than on NA plates, further demonstrating the role of growth medium composition on the mutability to aminoglycosides. Mutability to kanamycin resistance was increased following addition of sorbitol, suggesting that osmolarity is involved on the spontaneous mutability of E. coli K12 strains to aminoglycosides. The spontaneous mutation rates to kanamycin resistance on both L2 and NA plates were strictly associated with the selective antibiotic concentrations. Moreover, mutants selected at different antibiotic concentrations expressed heterogeneous resistance levels to kanamycin and most of them expressing multiple resistance to all tested aminoglycoside antibiotics (gentamicin, neomycin, amykacin and tobramycin). These results will contribute to a better understanding of the complex nature of aminoglycoside resistance and the emergence of spontaneous resistant mutants among E. coli K12 strains.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572003000200017	
Editor: 	Sociedade Brasileira de Genética	
Relação: 	10.1590/S1415-47572003000200017	
Formato: 	text/html	
Fonte: 	Genetics and Molecular Biology  v.26 n.2 2003	
Fonte: 	info:eu-repo/semantics/openAccess