Improved performance of the modified Hodge test with MacConkey agar for screening carbapenemase-producing Gram-negative bacilli

J Microbiol Methods. 2010 Nov;83(2):149-52. doi: 10.1016/j.mimet.2010.08.010. Epub 2010 Aug 27.


The detection of carbapenemases in Gram-negative bacilli is important for optimal patient treatment and to control spread of the resistance. The modified Hodge test can detect carbapenemase-producing Gram-negative bacilli. In this study, we compared the performance of MacConkey agar and Mueller-Hinton agar for metallo-β-lactamase (MBL) and OXA carbapenemase screening. Overall, the performance of Hodge test was better with MacConkey agar due to enhanced release of β-lactamases from the cells in the presence of bile compounds. Concomitant use of the modified Hodge test could resolve most of the problems with uncertain double-disk synergy tests in MBL detection.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Agar
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins / biosynthesis*
  • Culture Media / chemistry
  • Ertapenem
  • Gram-Negative Bacteria / drug effects
  • Gram-Negative Bacteria / enzymology*
  • Gram-Negative Bacterial Infections / microbiology*
  • Humans
  • Imipenem / pharmacology
  • Mass Screening / methods*
  • Microbial Sensitivity Tests / methods
  • beta-Lactamases / biosynthesis*
  • beta-Lactams / pharmacology


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Culture Media
  • beta-Lactams
  • Imipenem
  • Agar
  • beta-Lactamases
  • carbapenemase
  • Ertapenem