the gram-negative bacteria , especially escherichia coli , proteus-morganella group , enterobacter sp , serratia marcescens , and pseudomonas aeruginosa were generally more resistant to ampicillin , carbenicillin , cephalosporin , gentamicin , piperacillin , and trimethoprim-sulfamethoxazole at kfsh than in the united states .
C0002680
ampicillin
C0031955
piperacillin