Isolation of Campylobacter from human stool samples.

CONTEXT: Campylobacter is an undetected cause of diarrhoea especially under 5 years of age in most of the countries. Isolation of this organism is difficult, expensive and cumbersome. AIMS: Our objective of this study was to isolate this pathogen from the stool specimens on routinely available blood containing laboratory media using the candle jar for creating the microaerophilic atmosphere in our setup. SETTINGS AND DESIGNS: A descriptive study. MATERIALS AND METHODS: A total of 50 stool samples were inoculated onto selective and non-selective media with and without filtration using a 0.45 µm membrane. The inoculated media were simultaneously incubated in microaerophilic conditions using the Anoxomat as well as in candle jars at temperatures 37°C and 42°C. The culture isolates were confirmed by standard phenotypic tests. A simplex polymerase chain reaction (PCR) targeting the 16S ribosomal deoxyribonucleic acid of Campylobacter was performed on the deoxyribonucleic acid (DNA) of the culture isolates as well as on the DNA extracted from the stool filtrates. STATISTICAL ANALYSIS: Data was expressed as a proportion. RESULTS: Campylobacter could be isolated in 5 out of 50 stool samples using both the Anoxomat as well as the candle jar. Furthermore, we did not find any difference between the isolation using the selective and blood containing media as well as the different incubation temperatures. All the five were confirmed phenotypically and genotypically to be Campylobacter jejuni. The PCR results corroborated with that of the culture. CONCLUSIONS: Isolation by culture was as sensitive as that of the PCR.

Evaluation of source model coupled computational fluid dynamics (CFD) simulation of the dispersion of airborne contaminants in a work environment.

Dispersion of airborne contaminants in indoor air was evaluated employing physical measurement, empirical models, and computer simulation methods. Field data collected from a tray of evaporating solvent in the laboratory were compared with computational fluid dynamics (CFD) simulations coupled with evaporation models. The results indicated that mathematical models of evaporation can be coupled with CFD simulations to produce reasonable qualitative predictions of airborne contaminant levels. The airflow pattern within a room is primarily determined by the room layout and the position of the air supply diffusers. Variations in ventilation rate did not alter the airflow pattern, thus generating a characteristic concentration profile of the airborne contaminants.