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[Salmonella identification after incubation in the soil]
A Bakhrouf1, A Dhiaf, N Chnity
1Laboratoire d'Analyse et de Contrôle des Polluants Chimiques et Microbiologiques, Ministère de la Recherche Scientifique et de la Technologie, Faculté de Pharmacie de Monastir, Tunisie.
Archives De L'Institut Pasteur De Tunis
|April 10, 2004
Summary
Salmonella strains undergo biochemical changes in soil, becoming dormant and sometimes atypical. These modifications are reversible with nutrient broth, impacting bacterial identification in environmental samples.
Area of Science:
- Environmental microbiology
- Bacterial physiology
Background:
- Salmonella survival in soil is crucial for public health.
- Understanding bacterial adaptation to environmental stress is important.
Purpose of the Study:
- To investigate biochemical modifications of Salmonella in soil.
- To assess the reversibility of these changes and identify atypical strains.
Main Methods:
- Incubation of Salmonella in soil to induce dormancy.
- Biochemical testing for key enzymes (beta-galactosidase, lysine decarboxylase).
- Culturing stressed cells in nutrient broth for reviviscence analysis.
Main Results:
- Soil-induced stress caused loss of lysine decarboxylase and gain of beta-galactosidase activity.
- Stressed Salmonella produced acetoin.
- Atypical Salmonella strains were detected in wastewater sludge and irrigated soil.
- Reversibility of modifications was observed upon nutrient broth incubation.
Conclusions:
- Salmonella exhibits significant biochemical plasticity in soil environments.
- Environmental adaptations can lead to atypical phenotypes, complicating identification.
- Reversibility suggests a dynamic survival strategy for Salmonella in soil.