The Journal of Medical Microbiology, Vol 8, Issue 2 369-373, Copyright © 1975 by Society for General Microbiology
Induction of L-forms of Haemophilus influenzae in vitro
S. V. Want and J. R. May
The induction of L-forms of Haemophilus influenzae by penicillin,
amoxycillin and glycine has been studies in vitro on a nutrient-agar
medium. The minimal inducing concentrations of the antibiotics were
generally the same as their minimal inhibitory concentrations, but the
addition of a sub-inducing concentration of glycine lowered the minimal
inducing concentration of penicillin. Preliminary observations have shown
that L-forms are induced by penicillin or amoxycillin on a medium in which
mucoid sputum forms the sole source of nutrients, and that they remain
viable for at least 48 h in the absence of added osmotic stabiliser. The
minimal inducing concentration on "sputum agar" is within the range of
concentrations measured in sputum from patients receiving amoxycillin
therapy. The implications of these observations in relation to bactericidal
therapy of haemophilus infections of the respiratory tract are discussed.
