Comparative in vitro activity of ceftriaxone against clinical bacterial isolates in Nigeria

The in vitro activity of ceftriaxone, a cephalosporin derivative, recently introduced in Nigeria was compared with the activities of other related beta-lactam antibiotics such as cefotaxime, cefuroxime, cephaloridine, cloxacillin/ampicillin and ampicillin against 530 local clinical isolates of gram-negative and gram-positive bacteria. The spectra of activity and potency of ceftriaxone and cefotaxime were generally similar against the Enterobacteriaceae, Pseudomonas aeruginosa, Serratia spp., Streptococcus spp. and Neisseria gonorrhoeae, but less active against Staphylococcus aureus and Staphylococcus epidermidis when compared to cefotaxime. All the other beta-lactam antibiotics tested were less active than ceftriaxone. The action of ceftriaxone was bactericidal and the minimum inhibitory concentration values observed with R-plasmid beta-lactamase mediated resistant Escherichia coli, Klebsiella spp., Proteus spp. and N. gonorrhoeae strains did not exceed the maximum value obtained with the beta-lactamase-negative strains.