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Abstract Background and Objective: Salmonellosis is one of the most important food-borne bacterial zoonotic diseases worldwide, and poultry and its products are the major sources for salmonella transmission to human. Isolation of Salmonellaenterica from poultry needs bacteriologic enrichment and selected cultures of fecal samples. In this study, different culture methods for the isolation of salmonella from fecal samples were compared. Material and Methods: Forty- five positive samples from infected farms and 45 negative samples from normal farms were processed using enrichment media including tetrathionate broth, selenite cistine and Rappaport-Vassiliadis. Then the samples were incubated in selective cultures, and after 24 h, their results were compared with standard method. Results: Specificity of all methods for salmonella isolation was 100%, and salmonella was not isolated from the negative samples. The highest susceptibility was related to the method in which the sample first in Selenite cistine and later in Rappaport-Vassiliadis was enriched (100%). Enrichment in Rappaport-Vassiliadis could isolate 41 salmonella from 45 positive samples (91%) while the result of enrichment in tetrathionate was 6 isolates (13.3%). Conclusion: This study shows that enrichment in selenite cistine and then in Rappaport-Vassiliadis is currently the best method for isolating salmonella from fecal samples of poultry. Key words: Salmonella Bacteriologic Culture Diagnosis Isolation Enrichment Poultry

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Introduction: The poultry industry produces a large amount of waste, including chicken feathers, which are difficult to decompose and can cause environmental pollution. Keratinase enzymes, which can break down keratin, have the potential to be used in bioremediation of poultry waste. The objectives of this study were to screen for keratinolytic isolates from poultry waste, Identify the isolates using morphological, biochemical, and molecular methods; optimize the culture medium conditions for keratinase production and measure the keratinase activity of the isolates.
Materials and Methods: Two keratinolytic isolates were screened from poultry waste around Mashhad in Iran. The isolates were identified using morphological, biochemical, and molecular methods. The culture medium conditions for the two strains were optimized to enhance keratinase production. The keratinase activity was measured using azokeratin substrate and turbidity absorbance.
Results: The two isolates were identified as Bacillus pumilus and Bacillus teqlensis. The optimized culture medium conditions for keratinase production were pH 7.0, temperature 37°C, and incubation time 48 hours. The maximum keratinase activity of the two isolates was 120 U/mL and 100 U/mL, respectively.
Conclusions: The two Bacillus isolates have the potential to be used in bioremediation of poultry waste. The optimized culture medium conditions can be used for large-scale production of keratinase enzymes.
The keratinase enzymes produced by the two Bacillus isolates have the potential to be used in a variety of applications, including bioremediation of poultry waste, production of animal feed, and development of new cleaning products.