Mecillinam: a new antibiotic for enteric fever.

Mecillinam is a new antibiotic related to the penicillins but more active than ampicillin against salmonellae, including Salmonella typhi. Mecillinam must be administered parenterally, but the ester, pivmecillinam, is absorbed from the gut. Eight patients suffering from typhoid fever and one suffering from paratyphoid fever were treated with the antibiotic, and seven responded satisfactorily. One patient could not tolerate pivmecillinam because of vomiting but there were no other adverse reactions. Serum and bile levels of mecillinam were many times the minimum inhibitory concentrations for most salmonellae. The antibiotic is a promising addition to the agents available for treating typhoid.