Activity of cephazolin and other cephalosporins against Bacteroides fragilis

The antibiotic sensitivity of 50 strains of Bacteroides fragilis to four cephalosporin compounds, cephazolin, cephaloridine, cephradine and cephalexin is reported. Cephazolin was found to be the most active, 94 per cent of strains being susceptible to blood concentrations achieved on standard dosage, comparative findings with cephaloridine and cephradine were about 50 per cent, and only 22 per cent of strains were inhibited by cephalexin. The importance of infections due to bacteroides is discussed. Although not the treatment of choice, cephazolin, a view of its bacterial activity may be useful alternative for bacteroides infections but clinical trials are needed to confirm the laboratory results.