title: Comparison of screening methods for TEM- and SHV-derived extended-spectrum beta-lactamase detection.
abstract: OBJECTIVE
  To compare common extended-spectrum beta-lactamase (ESBL) screening methods and beta-lactams for their ability to detect TEM- and SHV-related ESBL enzymes.
  
  
  METHODS
  This study compared disk diffusion testing by NCCLS methodology, the Jarlier double disk test, a disk-on-disk test, a modified three-dimensional test and the E test method for their sensitivity and specificity in detecting TEM- and SHV-related ESBL producers. Three negative and 22 positive controls were studied. These were two Klebsiella pneumoniae and 23 Escherichia coli transconjugants. Seventeen beta-lactam antibiotics were tested: cefamandole, cefotetan, cefoxitin, cefuroxime, cefixime, cefoperazone, cefotaxime, cefpodoxime, cefsulodin, ceftazidime, ceftibuten, ceftizoxime, ceftriaxone, moxalactam, cefepime, cefpirome and aztreonam.
  
  
  RESULTS
  NCCLS disk diffusion was 14% sensitive with ceftriaxone, 36% with cefotaxime, 64% with aztreonam, 68% with cefpodoxime, and 73% with ceftazidime. Cefoperazone, cefamandole, cefpodoxime and cefpirome showed 91% sensitivity using the Jarlier test. Using the disk-on-disk test, cefsulodin showed 95% sensitivity, and cefoperazone, cefepime and cefamandole showed 91% sensitivity. With the modified three-dimensional test, cefoperazone, cefpodoxime and cefpirome showed 91% sensitivity.
  
  
  CONCLUSIONS
  For practical reasons, we would recommend use of either the Jarlier test or the commercial cephalosporin disks containing clavulanic acid to screen for ESBL producers. Cefoperazone, cefamandole, cefpodoxime and cefpirome showed good sensitivity across the methods tested.
authors.affiliation: Aberdeen Royal Infirmary, UK. f.m.mackenzie@abdn.ac.uk
authors.forename: F M
authors.initials: FM
authors.lastname: MacKenzie
authors.forename: C A
authors.initials: CA
authors.lastname: Miller
authors.forename: I M
authors.initials: IM
authors.lastname: Gould
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004058:Diffusion; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology*; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology*; D008826:Microbial Sensitivity Tests / Q000379:methods*; D012680:Sensitivity and Specificity; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000378:metabolism*; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases