Epicillin

The antibacterial activities of three aminopenicillins ampicillin, epicillin and amoxycillin were compared in vitro and in vivo. The minimum inhibitory concentrations (MIC) of the three penicillins were very similar and the compounds were active against non-beta-lactamase-producing strains of Escherichia coli, Salmonella and Shigella species, Proteus mirabilis, Haemophilus influenzae and Neisseria gonorrhoeae. Streptococci including Streptococcus faecalis, and non-beta-lactamase-producing staphylococci were also sensitive to the compounds but Pseudomonas aeruginosa, Klebsiella aerogenes, Enterobacter and indole-positive Proteus species were resistant. At concentrations close to MIC value epicillin and ampicillin showed similar bactericidal activity against E. coli and against S. typhi and both compounds caused a slower rate of kill than was seen with amoxycillin. Microscopical observation of the cells exposed to ampicillin and epicillin for 1 h showed the presence of filamentous forms which lysed slowly, whereas cells exposed to amoxycillin for the same period rapidly. Epicillin was similar to or slightly less active than ampicillin against experimental mouse infections, and against the majority of infections both compounds were significantly less effective than amoxycillin by the oral and subcutaneous routes of administration.

Two hundred and sixty male patients with gonorrhoea, allocated to 4 unequal groups, were treated with one single oral dose of: (a) 2 g epicillin plus 1 g probenecid, (b) 2 g epicillin alone, (c) 1 g epicillin, 1 g cephradine plus 1 g probenecid, and (d) 1 g epicillin and 1 g cephradine. The last 3 groups acted as controls. Follow-up, with cultures of urethral discharge, was carried out over a 2-week period in all patients. The most satisfactory results were in the group of patients receiving epicillin plus probenecid, a 97% cure rate being achieved, with urethral discharge disappearing within 24 hours of treatment.

One hundred patients with acute enteric fever were randomly assigned to treatment with either chloramphenicol 50 mg/kg body-weight or epicillin 1 g six hourly. Eighty-one patients had a positive blood culture for typhoid or paratyphoid bacilli and nineteen had a positive stool culture with a significant Widal titre. All fifty patients in the group treated with chloramphenicol responded, however there was one relapse with bacteraemia. In the group treated with epicillin, six from the total of fifty patients were considred treatment failures. Treatment was considred as a failure if the patient was febrile after ten days treatment or if there was a deterioration despite antibiotic therapy.