Dw. Haas et al., DIMINISHED ACTIVITY OF CEFTIZOXIME IN COMPARISON TO CEFOTAXIME AND CEFTRIAXONE AGAINST STREPTOCOCCUS-PNEUMONIAE, Clinical infectious diseases, 20(3), 1995, pp. 671-676
Previous reports documenting the essentially identical spectra of acti
vity of ceftizoxime, cefotaxime, and ceftriaxone prompted our hospital
formulary committee to replace the latter two drugs with ceftizoxime
on the basis of cost differences. However, we subsequently observed th
at every one of 60 isolates of Streptococcus pneumoniae tested was les
s susceptible to ceftizoxime than to either cefotaxime or ceftriaxone.
The difference between minimal inhibitory concentrations (MICs) was g
reatest for strains moderately or fully resistant to penicillin, which
at our institution represent similar to 32% of all isolates of S. pne
umoniae. Ten isolates with cefotaxime and ceftriaxone MICs of 2.0-6.0
mu g/mL had ceftizoxime MICs of greater than or equal to 256 mu g/mL.
Time-kill kinetic studies assessing bactericidal activity confirmed th
e diminished activity of ceftizoxime against penicillin-resistant isol
ates of S. pneumoniae. Ceftizoxime should not be used to treat proven
or suspected pneumococcal infection in areas where resistance to penic
illin is prevalent.