OCENA WRAŻLIWOŚCI NA CEFOPERAZON/SULBAKTAM SZCZEPÓW PAŁECZEK GRAM-UJEMNYCH IZOLOWANYCH OD CHORYCH HOSPITALIZOWANYCH
[ASSESSMENT OF THE SUSCEPTIBILITY OF THE GRAM-NEGATIVE RODS ISOLATED FROM HOSPITALIZED PATIENTS TO CEFOPERAZONE/SULBACTAM]

Streszczenie.

Rozprzestrzenianie się oporności na antybiotyki beta-laktamowe wśród szczepów Gram-ujemnych pałeczek stanowi poważny problem. Jedną z opcji terapeutycznych stanowi stosowanie antybiotyku beta-laktamowego z inhibitorem beta-laktamazy. Badano wrażliwość na cefoperazon/sulbaktam 197 szczepów pałeczek Gram-ujemnych, w przypadku których przynajmniej jedna metoda fenotypowa wskazywała na wytwarzanie beta-laktamazy o rozszerzonym spektrum (ESBL).

Abstract.

The susceptibility to cefoperazone/sulbactam of 197 strains of Gram-negative rods demonstrating an ESBL-positive phenotype was determined. The assortment of the investigated strains was as follows (numbers of strains are given in the brackets): E.cloacae (63), S.marcescens (46), K.pneumoniae (21), P.mirabilis (17), E.coli (9), P.vulgaris (8), P.aeruginosa (20) and A.baumanni (13). 83 strains from 197 were susceptible (42.1%). The MIC values were determined and the disc-diffusion method was performed. The susceptibilities among particular species were as follows (the order of data in the brackets is: % of the susceptible strains/MIC50/MIC90): E.cloacae (54.0/16/64), S.marcescens (23.9/64/≥128), K.pneumoniae (38.1/32/64), P.mirabilis (41.2/32/64), E.coli (44.4/32/32), P.vulgaris (75.0/8/32), P.aeruginosa (35.0/32/64), A.baumannii (46.2/32/64). Using disc-diffusion method, for 184 strains the difference between diameter of the inhibition zone around the disc with cefoperazone and the disc with cefoperazone/sulbactam was calculated. This difference amounted 5 mm or more
in the case of 76.6% of the investigated strains. The results indicate that the comparison of the inhibition
zones around cefoperazone and cefoperazone/sulbactam discs may be an additional method useful for phenotypic detection of ESBL producing organisms. These results highly correlated with results obtained by using analogous test with cefpirome and cefpirome/clavulanic acid (85,6 % of concordance).