COMPARING ANTIMICROBIAL ACTIVITY AGAINST RESISTANT PSEUDOMONAS-AERUGINOSA USING AN INDEX FOR THE ABSENCE OF CROSS-RESISTANCE

We devised an index to estimate the degree cross-resistance between pi peracillin, ceftazidime, sulbactam/cefoperazone, amikacin, tobramycin, carumonam and imipenem against 139 separate clinical isolates of Pseu domonas aeruginosa. A negative value of the index indicated the cross- resistance whereas a positive value suggested the converse making the device an index for the absence of cross resistance (ACR). Using the A CR index, we identified pairs of antibiotics exhibiting the least degr ee of cross-resistance and therefore the highest potential for treatin g infections due to P. aeruginosa.