An improved broth-microdilution procedure for testing metal ion resistance of Klebsiella pneumoniae.

A new broth-microdilution method for testing metal ion resistance was designed in order to circumvent the formation of insoluble complexes between cations and compounds of the test medium. High-level cefotaxime resistant K. pneumoniae isolates tested by this procedure proved to be susceptible to Cd, Hg and Zn but resistant to Pb, Mo and W. The metal ion resistance was not linked to the beta-lactam resistance gene.