[Clinical significance of the determination of ESBL (extended- spectrum beta-lactamase) production by gram-negative nosocomial bacteria].

BACKGROUND

Data on the incidence of multiresistant nosocomial bacterial strains of Xanthomonas (Stenotrophomonas) maltophilia, producing in addition to metallo-beta-lactamases also new types of broad spectrum beta-lactamases (ESBL) called for analyses of the production of different types of enzymes.

METHODS AND RESULTS

Nosocomial multiresistant strains of Xanthomonas (Stenotrophomonas) maltophilia isolated from patients in 1996 were tested for the production of ESBL by a double diffusion disc test. The production of different types of ESBL was revealed, in particular production of ESBL specific for inactivation of aztreonam which is reversible by the action of clavulanate. The test of ESBL production, proved suitable also for orientation as regards selection of a suitable antibiotic in the treatment of infections caused by multiresistant or naturally resistant bacteria, possibly also the possible synergic action of antibiotics may be detected. The effect of mutual action of different antibiotics with a different inhibitory action of beta-lactamase inhibitors is illustrated when the test of ESBL production is used, where the effect of aztreonam on the inhibition of growth of ofloxacin resistant colonies was proved.

CONCLUSIONS

The double diffusion test of production of new beta-lactamases (EBL) in multiresistant Gram-negative nosocomial strains made it possible to detect the possible synergic action of antibiotics in combination with the action of beta-lactamase inhibitors.