Use of a Commercially Available Microarray to Characterize Antibiotic-Resistant Clinical Isolates of Klebsiella pneumoniae.

A commercially available microarray (IDENTIBAC AMR-ve) for the detection of antibiotic resistance determinants was investigated for its potential to genotype 30 clinical isolates and two control strains of Klebsiella pneumoniae. Resistance profiles and the production of extended-spectrum β-lactamases were determined by disc diffusion and the results were compared with the microarray profiles in order to assess its scope and limitations. Genes associated with resistance to a wide range of antibiotics, including current first line therapy options, were detected. In addition, the array also detected class 1 integrases. The array is easy to use and interpret, and is useful in providing a general description of the numbers and types of resistance determinants in K. pneumoniae. It also provides an indication of the potential for resistance gene acquisition. However, in most instances detected resistance to specific antibiotics could not unequivocally be assigned to hybridization with a specific array probe. We conclude that the microarray is a valuable and rapid means of investigating the presence of resistance gene classes of therapeutic importance. It can also provide a starting point for selecting analyses of greater resolving power, such as phylogenetic subtyping by PCR sequencing.