Evaluation of methods for detection of β-lactamase production in MSSA

Details

• Alternative Title:
  J Antimicrob Chemother
• Personal Author:
  Skov, Robert ; Lonsway, David R. ; Larsen, Jesper ; Larsen, Anders Rhod ; Samulioniené, Jurgita ; Limbago, Brandi M.
• Description:
  Objectives:
  
  Correct determination of penicillin susceptibility is pivotal for using penicillin in the treatment of Staphylococcus aureus infections. This study examines the performance of MIC determination, disc diffusion and a range of confirmatory tests for detection of penicillin susceptibility in S. aureus.
  
  Methods:
  
  A total of 286 consecutive penicillin-susceptible S. aureus blood culture isolates as well as a challenge set of 62 MSSA isolates were investigated for the presence of the blaZ gene by PCR and subjected to penicillin-susceptibility testing using broth microdilution MIC determination, disc diffusion including reading of the zone edge, two nitrocefin tests and the cloverleaf test.
  
  Results:
  
  Using PCR-based detection of blaZ as the gold standard, both broth microdilution MIC testing and disc diffusion testing resulted in a relatively low accuracy (82%–93%) with a sensitivity ranging from 49%–93%. Among the confirmatory tests, the cloverleaf test performed with 100% accuracy, while zone edge interpretation and nitrocefin-based tests increased the sensitivity of β-lactamase detection to 96%–98% and 82%–96% when using MIC determination or disc diffusion as primary test, respectively.
  
  Conclusions:
  
  This investigation showed that reliable and accurate detection of β-lactamase production in S. aureus can be obtained by MIC determination or penicillin disc diffusion followed by interpretation of the zone edge as a confirmatory test for apparently penicillin-susceptible isolates. The more cumbersome cloverleaf test can also be used. Nitrocefin-based tests should not be used as the only test for confirmation of a presumptive β-lactamase-negative isolate.
  
  
• Subjects:
  Anti-Bacterial Agents Article Beta-Lactamases Microbial Sensitivity Tests Penicillins Staphylococcus Aureus
• Source:
  J Antimicrob Chemother. 76(6):1487-1494
• Pubmed ID:
  33615356
• Pubmed Central ID:
  PMC9479532
• Document Type:
  Journal Article
• Volume:
  76
• Issue:
  6
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:8b144be0067690bffd37413e4e5b875b6f99ff8ad5f75047bffa7d54b38419ac
• Download URL:
  https://stacks.cdc.gov/view/cdc/121274/cdc_121274_DS1.pdf
• File Type:
  [PDF - 812.79 KB ]