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[Comparison of Campylobacter jejuni isolation methods and the effect of moisture content on colony morphology]
Abstract:
Several isolation methods and media and the effect of moisture content on colony morphology were compared for the primary isolation of Campylobacter jejuni. Of the 200 rectal swabs from cattle and sheep tested for the isolation of C. jejuni, 19.5% were positive on Butzler medium and 16.5% were positive on Skirrow medium. The transportation of samples in modified Cary-Blair medium increased the isolation rate. Of the 300 gallbladder from cattle and sheep tested for the isolation of C. jejuni, 5% were positive by direct inoculation of bile, 27% were positive by swabbing and 31% were positive by selective enrichment method. The organism produced two different type of colonies on fresh and dried media.
Insights
Optimizing Campylobacter jejuni isolation from livestock is crucial. Selective enrichment and modified Cary-Blair medium significantly improve detection rates from rectal swabs and gallbladders.
Area of Science:
- Veterinary Microbiology
- Food Safety
- Bacterial Pathogenesis
Background:
- Campylobacter jejuni is a leading cause of bacterial gastroenteritis globally.
- Accurate isolation methods are essential for surveillance and control in livestock.
- Previous studies highlight variability in Campylobacter jejuni isolation techniques.
Purpose of the Study:
- To compare various isolation methods and media for Campylobacter jejuni.
- To evaluate the impact of sample type (rectal swabs, gallbladders) on isolation efficiency.
- To assess the effect of moisture content on Campylobacter jejuni colony morphology.
Main Methods:
- Comparative analysis of Butzler and Skirrow media for Campylobacter jejuni isolation from 200 rectal swabs.
- Evaluation of modified Cary-Blair medium for sample transportation.
- Comparison of direct inoculation, swabbing, and selective enrichment for isolating Campylobacter jejuni from 300 gallbladders.
- Observation of colony morphology under varying moisture conditions.
Main Results:
- Butzler medium yielded a 19.5% isolation rate, while Skirrow medium yielded 16.5% from rectal swabs.
- Transportation in modified Cary-Blair medium enhanced Campylobacter jejuni isolation rates.
- Selective enrichment of gallbladders resulted in a 31% isolation rate, significantly higher than direct inoculation (5%) or swabbing (27%).
- Campylobacter jejuni exhibited distinct colony morphologies on fresh versus dried media.
Conclusions:
- Selective enrichment and modified Cary-Blair medium are superior methods for Campylobacter jejuni isolation from livestock.
- Optimized isolation protocols are critical for accurate Campylobacter jejuni surveillance in cattle and sheep.
- Understanding factors affecting colony morphology aids in accurate identification and differentiation.