Answer by
worker9181 (47)
Since bacteria are not all the same, different antibiotics need to be used based on which bacteria is causing the problem. Cephalexin is a cephalosporin, which work by disrupting the way that the bacteria make their cell wall. If the infection is caused by MRSA, B. fragilis, Pseudomonas, Enterobacter, P. mirabilis, or a few other bacteria, it will not work.