Introduction:

Klebsiella pneumoniae is the first pathogen to be found producing extended-spectrum beta-lactamases (ESBLs), mainly due to TEM and SHV enzymes gene mutation. The mutation development is facilitated by frequent empiric use of third generation cephalosporins in the ICU setting.

Methods:

To detect the presence of ESBL, we use Double Disc Synergy Test, utilising the following discs: amoxicillin/clavulanic acid (AMC)-disc contents 20/10 mg, ceftazidime (CTZ) – 30 mg, cefpodoxime (CPD) – 10 mg, aztreonam (AZT) – 30 mg. The test is based upon the susceptibility of extended spectrum beta-lactamases to clavulanic acid. A positive result is manifested by characteristic extension of inhibition zone between the discs with AMC and a third generation cephalosporin (or AZT). The test is performed in K. pneumoniae strains that show intermediate susceptibility or resistance to second and third generation cephalosporins.

Results:

From 2000 till 2003, the number of patients who tested positive for ESBL producing strains of K. pneumoniae dropped from 80 (17%) down to 2 (0.4%). Concurrently, the use of third generation cephalosporins (ceftazidime, cefotaxime, ceftriaxone, cefoperazone) was reduced from 3.5 g down to 2 g per one hospitalised patient. A certain contribution should also be attributed to a more strict adherence to hygienic guidelines (patient isolation, handwashing, single-use devices, etc.).

Summary:

The incidence rate of multiresistant, ESBL-producing strains of K. pneumoniae may be mitigated by controlled broad-spectrum antibiotic use and a stricter adherence to hygienic guidelines.