[Antibiotics and hematopoiesis: toxicity of beta-lactam on in vitro granulopoiesis].

The neutropenia induced by beta-lactam antibiotics conduct us to study the in vitro effect of these antibiotics on human granulopoiesis. We use a semi-solid medium (agar) with placenta conditioned medium as support of granulo-monocytic progenitors growth. We tested the inhibitory effect of prolonged exposure of bone marrow cells to several classes of beta-lactam antibiotics. We found a dose-dependent inhibition in all cases, more pronounced for cephalosporins than for ureido-penicillins. A short (1 hour) exposure was less toxic and could explain the rare occurrence of neutropenia in patients treated with these drugs.