Penetration of a single infusion of ampicillin and sulbactam into prostatic tissue during transurethral prostatectomy.

Antibiotic prophylaxis is recommended in endoscopic urological operations to diminish the rate of intraoperative septic complications and relevant urogenital infections. The objective of the study was to determine the tissue concentrations of preoperatively administered ampicillin and sulbactam in the human prostate in patients undergoing transurethral resection (TUR-P) for benign prostatic hyperplasia (BPH). In 19 patients (mean age 68.7 years) the serum and tissue concentrations of ampicillin and sulbactam were determined. For all patients the dosage was administered as a single infusion over 15 min at a 2:1 ratio, i.e. 2 g ampicillin and 1 g sulbactam. The serum and prostatic tissue samples were taken 15 to 55 min (mean 29.5 min) after infusion. Of transurethral resected prostatic chips 3 g were immediately collected after resection and stored at -70 degrees C. Ampicillin was determined by bioassay and sulbactam was determined by gas chromatography/mass spectrometry. Tissue concentrations of ampicillin ranged from 0.42 to 548.33 mg/kg (median 47 mg/kg). Tissue concentrations of sulbactam ranged from 0.15 to 249.74 mg/kg (median 19 mg/kg). Six (32%) of 19 patients showed a tissue concentration of ampicillin <4 mg/kg (MIC90), respectively 5 (26%) patients of sulbactam <8 mg/kg. The mean serum concentrations at tissue sampling time were 118.8+/-48.9 mg/l respectively 32.2+/-12.2 mg/l. There exists a high variability of intraprostatic concentrations of ampicillin and sulbactam after single infusion in patients with BPH. In a relevant part of patients both compounds do not exceed the minimal inhibitory concentrations (MIC) of important bacterial pathogens. A single shot infusion of 3 g ampicillin/sulbactam for intraoperative antibiotic prophylaxis is not sufficient in patients undergoing TUR-P. It seems that the prostate cannot be compared to other tissues in view of penetration of ampicillin/sulbactam.