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Genetics of resistance to third‐generation cephalosporins in clinical isolates of Streptococcus pneumoniae
Author(s) -
Muñoz Rosario,
Dowson Christopher G.,
Daniels Maggie,
Coffey Tracey J.,
Martin Christiane,
Hakenbeck Regine,
Spratt Brian G.
Publication year - 1992
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1992.tb01422.x
Subject(s) - biology , streptococcus pneumoniae , cephalosporin , microbiology and biotechnology , third generation , virology , pneumococcal infections , antibiotics , telecommunications , computer science
Summary Resistance to third‐generation cephalosporins in a clinical isolate of Streptococcus pneumoniae was shown to be due to the production of altered forms of penicillin‐binding proteins (PBPs) 2X and 1A. The cloned PBP2X gene from the resistant strain was able to transform a susceptible strain to an intermediate level of resistance. The resulting transformant could be transformed to the full level of resistance of the clinical isolate using the cloned PBP1A gene from the latter strain. Chromosomal DNA from the resistant strain (and from other resistant strains) could readily transform a susceptible strain to the full level of resistance to third‐generation cephalosporins (>250‐fold for cefotaxime; >100‐fold for ceftriaxone) in a single step (transformation frequency of about 10 ‐5 ). The resistant transformants obtained with chromosomal DNA were shown by gene fingerprinting to have gained both the PBP1A and PBP2X genes from the DNA donor.