Microbiological assay of ampicillin in serum and aqueous humor of patients given ampicillin-sulbactam injection.

The aim of this study was to determine the bacterial growth inhibitory activities of ampicillin in aqueous humor and serum of patients administered ampicillin-sulbactam combination intramuscularly prior to cataract surgery. 43 patients received a combination of both antibiotics intramuscularly at varying periods (60-140 minutes) prior to surgery. Aqueous humor and venous blood were collected at the beginning of the surgery. For microbiological assay, spores of Bacillus subtilis were incorporated in the agar. The test sample and the standard solutions (calibrators) of ampicillin and ampicillin-sulbactam combination were placed in 3 mm wells in the agar. The diameter zones of growth inhibitory activities of ampicillin of the calibrators and the test samples measured in mm were extrapolated to the standard curve and were recorded as ampicillin activity in micrograms/ml. The results of the assay were placed in 5 groups according to the time intervals between injection and collection of serum and aqueous humor (< or = 70, 75, 80, 90, > 90 minutes). Ampicillin activities in sera and aqueous humor of group 5 (> 90 minutes) were significantly higher than the others (p < 0.001). The ratio of ampicillin activities of sera and aqueous humor in group 5 patients was significantly lower indicating higher concentration of ampicillin activity in aqueous humor during this period. Bacterial growth inhibitory activities of ampicillin-sulbactam combination were adequate in aqueous humor of all patients with highest activity being 90 minutes after intramuscular administration indicating the potential usefulness of this antibiotic combination as chemoprophylaxis prior to cataract surgery.

In vitro activities of tetracycline & ciprofloxacin against Chlamydia trachomatis isolates from conjunctivitis patients.

Twenty seven Chlamydia trachomatis isolates from patients of conjunctivitis were tested for their in vitro sensitivities to ciprofloxacin and tetracycline in cyclohexamide treated McCoy cells on cover slip (shell vial) cultures. After a 48 h exposure of chlamydia infected monolayers to varying concentrations of each of the drugs, the cover slips were processed and stained for detection of major out membrane protein of C. trachomatis by fluorescent antibody test (FAT) using fluorescein conjugated monoclonal. Minimum inhibitory concentration (MIC90) and minimum lethal concentration (MLC90) of ciprofloxacin were 2.9 micrograms/ml and 5.7 micrograms/ml and for tetracycline 9.1 micrograms/ml and 18.0 micrograms/ml respectively. Ciprofloxacin may have a more promising role in treating chlamydial conjunctivitis than the commonly used tetracycline.