Cefotaxime, desacetyl-cefotaxime, and bactericidal activity in spontaneousbacterial peritonitis

We have prospectively studied 13 episodes of spontaneous bacterial peritoni tis (SBP) in 12 patients treated with cefotaxime (CTX)2 g intravenously eve ry 8 h (mean duration, 5.3 days). Ascitic fluid was inoculated at the bedsi de. The cultures were done before, during (day 3 after CTX initiation), and 48-72 h (mean, 56 h) after the end of therapy. All SEP episodes were monom icrobial. During treatment, the concentrations of CTX and desacetyl-cefotax ime (d-CTX) in ascitic fluid were high in all 13 SEP episodes, and d-CTX wa s still present in 6 patients who had residual ascitic bactericidal titer ( ABT) activity after the last dose of CTX. ABTs were greater than or equal t o 1 : 128 during CTX therapy in 12 episodes and were measurable in 7 patien ts after the last dose. All patients were cured. The present study provides scientific rationale to the clinical studies that suggest treating SEP epi sodes with lower doses of antibiotics and shorter treatment duration.