The presence of aminoglycoside antibiotics interferes with the determination of clindamycin levels by standard microbiological assay. A new bioassay method of quantitation of clindamycin in the presence of aminoglycosides is presented. This technique is based on the fact that incorporation of calcium chloride into assay agar blocks the antimicrobial activity of aminoglycosides against Sarcina l...

The serial-dilution assay is a standard microbiological method for estimating the density of organisms in a solution. The commonly used interval-estimation procedures of Woodward and deMan are described and compared. A new method for the calculation of two-sided confidence intervals, which is superior to the standard procedures, is presented. The computations are illustrated for a decimal dilut...

SYNOPSIS The effects of purified beta-lactamase from Bacillus cereus on the activity of four cephalosporins are described. Drug inactivation was measured spectrophotometrically and confirmed by microbiological assay and by microbiological techniques involving determinations of minimum inhibitory concentrations and growth curves of Staphylococcus aureus NCTC 6571 (Oxford) in broth containing dru...

75Se-selenofolate radioassay was adapted for the purpose of red cell folate measurement. The results of assay of 124 whole blood samples by Lactobacillus casei microbiological assay and by radioassay using the adapted selenofolate method were concordant (r = 0.8). Red cell folate levels by the radioassay were below 170 microgram/1 in people who had haematological features of folate depletion. T...

The relative responses of neomycins B and C have been determined by a microbiological agar-diffusion method, a turbidimetric method, and by a recently developed gas-liquid-chromatographic (GLC) method capable of separating the neomycin isomers. The ratios of response of neomycin C to neomycin B by the individual methods were as follows: agar-diffusion method, 1:3; turbidimetric method, 1:2.5; a...

The extensive use of microbiological procedures for the determination of vitamins is well known. Although most of these methods have rather general applicability, it is possible that the conditions of a particular experiment might require alteration of the medium in order to insure its adequacy for the samples being analyzed. Such a situation might well arise in connection with the Lactobacillu...

The study was undertaken to prospectively evaluate a Streptococcus pneumoniae urinary antigen test for diagnosis of pneumococcal pneumonia among patient and control groups between 2004 and 2006. Microbiological analysis for these patients included Gram staining for sputum, sputum and blood culture. Nonconcentrated urine samples were tested using an immunochromatographic assay, the NOW S.pneumon...

The objectives of this study were to assess the microbiological quality of Egyptian yoghurt and to investigate the antagonistic activity of some probiotic bacteria against some food borne pathogens in vitro and in yoghurt. The results indicated a poor microbiological quality of yoghurt, since the microbiological parameters recorded higher values than the admissible levels. Results from the agar...