[Diffusion of aztreonam in the tissues and biological fluids of the female genital tract].

Diffusion of aztreonam into female genital tract tissues was investigated. After a single IV injection of 1 g, aztreonam was assayed in uterine tissue, uterine tube tissue and peritoneal fluid in 15 patients undergoing coelioscopy or hysterectomy. In addition, to evaluate placental transfer of aztreonam, maternal blood, amniotic fluid and cord blood samples were collected in five women undergoing cesarean section. Concentrations of aztreonam were determined using a microbiologic method. Mean concentrations 1 to 2 hours after administration of the drug were 11 to 25 micrograms/g in the endometrium and uterine tube tissue and 18 to 30 micrograms/g in the myometrium. Concentrations in peritoneal fluid samples were lower, ranging from 4.7 micrograms/ml (0.5 h) to 16 micrograms/ml (1 to 2 hours after the injection). The ratio of tissue concentrations to serum concentrations found at the same time, expressed as a percentage, ranged from 50 to greater than or equal 100%. Placental transfer of aztreonam proved comparable to that of other recently studied beta-lactams: the amniotic fluid/maternal blood and cord blood/maternal blood ratios ranged from 27 to 33% thirty minutes after administration of the antibiotic. No adverse effects were recorded in the offspring. These results indicate that diffusion of aztreonam into female genital tract tissues is good, producing concentrations capable of preventing or curing gynecologic and obstetrical infections caused by Gram negative bacilli.