Streptococci and the Host pp 429-433 | Cite as
Genetic Studies of Cefotaxime Resistance in Streptococcus pneumoniae
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Abstract
In clinical isolates of highly β-lactam-resistant pneumococcal strains, the penicillin-binding proteins (PBP) are usually altered resulting in a decrease in penicillin affinity. PBP gene sequences of alleles conferring resistance are mosaïcs of pneumococcal and closely related streptococcal sequences. This results from « horizontal transfer » of PBP gene fragments from oral Streptococci toward Streptococcus pneumoniae by DNA induced transformation (1). However, clinical isolates are non isogenic and the strains from which they originated are not known. Therefore it is not possible to correlate resistance levels with specific sequence modification in the PBP genes. In order to bypass such difficulties, a series of independent, spontaneous mutants resistant to high levels of β-lactam were isolated from the laboratory strain R6 by Laible and Hakenbeck (5). A family of strains has been selected for resistance to cefotaxime, a cephalosporin that binds to PBPs other than PBP2b (4). One of the strains, C506, resistant to 1 μg/ml, was used to define the genes that had been mutated during the progressive selection procedure.
Keywords
Clinical Isolate Streptococcus Pneumoniae Susceptible Strain Oral Streptococcus Pneumococcal StrainPreview
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References
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