Action of Penicillin on Leptospira

Leptospirosis in England and Wales

“…In animal experiments it was shown by Heilman and Herrell (1944) and by Alston and Broom (1944) that this antibiotic could prevent the appearance of symptoms in guinea-pigs, provided that treatment was begun within 24 hours of infection with L. icterohaemorrhagiae. These observers, however, and also Augustine, Weinman, and McAllister (1944), found the drug completely inactive if it was withheld until the animals showed signs of illness.…”

Conference on Audio-Visual Education

“…Primary bacterial proliferation preceding bacteriostasis, as! occurs with sulphonamides, has recently been noted with penicillin and Leptospira icterohremorrhagire 10 • (As mentioned previously, this may well be another aspect of the biphasic phenomenon.) Penicillin growth-inhibition, in conformity with that of sulphonamides, appears to obey the law of mass action, in that (a) the inhibition is reversible, by removing the bacteria from contact with penicillin or destroying the penicillin with penicillinase, and (b) the inhibition is directly related.…”

Further Observations on the Treatment of Leptospirosis

“…Discussion.-It seems well established that penicillin is leptospirocidal in concentrations of one unit per millilitre and higher, and in lower concentrations for some strains, and that it is leptospirostatic in concentrations between o' 03 and one unit per millilitre (Jennings, 1949;Alston and Broom, 1944), although some workers have considered it leptospirostatic at all effective concentrations (Chang, 1946;Rosenberg, 1951). Published work (Eagle et alii, 1949) suggests that the higher penicillin dosages used would produce a blood level within the leptospirocidal range in all cases, while the lower dosage would produce a blood level that would be leptospiro static for most strains.…”