The Serum Concentration of Bactericidal Antibiotics (Rifampicin, Cephaloridine) in Relation to the Low Resistance Period in Experimental Infections

Abstract

The minimum inhibitory concentration of bactericidal as opposed to bacteriostatic agents does not necessarily have to be maintained in the blood for the full duration of the low resistance period (LRP). Even brief exposure to concentrations which are bactericidal or high enough to induce bacteriopause can effectively suppress the infection. The longer the LRP, the more sustained must be the antibacterial effect. The relations between these factors are examined with reference to the effect of single doses of rifampicin and cephaloridine in a series of experimental infections in the mouse.

Rifampicin and Rifapentine in Treatment of Experimental Listeriosis in Normal Mice and Athymic (Nude) Mice

“…These results in mice with intact host defense support the studies of other inves tigators. Sackmann already noted that ri fampicin was highly active in intraperito neal infections caused by L. monocyto genes in mice; rifampicin in a single low dose, administered immediately after in fection, resulted in an increased survival rate, whereas cephaloridine was ineffec tive [12]. The observation that rifampicin was much more effective in the treatment of murine listeriosis than ampicillin, con firmed the experiments of Vischer and Rominger [15] and Mandell and Vest [8] who compared the activity of rifampicin and penicillins in experimental infections caused by L. monocytogenes or S. aureus.…”