Which of the following cephalosporins has activity against gram-negative anaerobic pathogens like Bacteroides fragilis?
A. Cefoxitin.
B. Cefepime.
C. Ceftriaxone.
D. Cefazolin.
Correct answer = A.
The cephamycins (cefoxitin and cefotetan) are the only cephalosporins with in vitro activity against anaerobic gram-negative pathogens. Cefepime, ceftriaxone, and cefazolin have no appreciable activity against Bacteroides fragilis.