[Comparison of two phenotypic methods for detecting the production of extended-spectrum beta-lactamases by hospital Klebsiella pneumoniae strains].

In the period 2006-2008, the Republican Emergence Medical Care Center.isolated 2997 enterobacteria, 48.9% of which belonged to Klebsiella pneumoniae. Confirming phenotypic methods, such as double disk method (DDM) and double disk synergy test (DDST), were used to examine 64 K. pneumoniae strains that had been regarded as being suspected to produce extended-spectrum beta-lactamases (ESBL) during a preliminary screening. Of the 64 K. pneumoniae strains, 6 (9.4%) were unsusceptible to clavulanate and not referred to as ESBL producers and 5 (7.8%) were resistant to imipenem. DDM ranks below DDST as it (concurrently with DDST) yielded positive results only in 30 (51.7%) strains; 28 (48.3%) cultures were positive only with DDST - these strains were significantly more frequently resistant to three third-generation test cephalosporins during primary screening.