Molecular Characterization and Extended Spectrum Betalactamase Detection in E. coli and K. pneumoniae Strains Isolates from Intensive Care Units in a Teaching Hospital

Extended Spectrum Betalactamases production from E. coli and K. pneumoniae strains, is a serious public health problem since cause loss of therapeutic effectiveness of betalactams antibiotics. In this research the presence of extended spectrum betalactamases was investigated in E. coli and K. pneumoniae strains isolated from intensive cares unit patient’s in a teaching hospital. 41 E. coli and 59 K. pneumoniae strains isolated from bacteriological cultures carried out in the Bacteriological Reference Centre at Autonomous Service Maracaibo´s University Hospital (SAHUM) were studied. For the detection of extended spectrum betalactamases the normalized methods proposed by Clinical and Laboratory Standards Institute were used. 39,02% of E. coli and 52,54% K. pneumoniae was positive for extended spectrum betalactamases production, in these isolates accompanying resistance to quinolones, aminoglycosides, chloramphenicol, tetracycline and trimethoprim/sulfamethoxazole was detected. The epidemiological research by means of pulsed field gel electrophoresis showed a great genetic diversity among these strains, this polyclonal pattern, allows to determine that dissemination inside the hospital services is not given by transmission of a single clone among patients, but rather it is given by plasmids transfer among different strains product of the selective high pressure exercised by third generation cephalosporins bad use.