Isolation, identification, and molecular characterization of probiotic bacteria from locally selected Ethiopian free range chickens gastrointestinal tract.

The poultry industry is facing continuous challenges with regard to increased feed costs and loss due to infectious disease. To overcome this challenge, several antibiotics have been used along with chicken feeds to promote growth. Nevertheless, the use of antibiotics as growth promoter has been banned in many countries, due to the concerns associated with potential risks of emerging and horizontal transfer of multidrug resistant genes to bacteria in animal tissues. The objective of this study was to identify and characterize potential probiotic bacteria strains from the gastrointestinal tract of free-range locally selected chickens. The bacterial isolates were screened, purified and characterized based on morphological, biochemical and molecular characteristics from 12 well-adopted free-range healthy young chickens. Low pH and bile salt tolerance, antagonistic activity, antibiotic activity, hemolysis activity, adhesion to the chicken intestine and carbohydrate fermentation tests was conducted to identify potential probiotic bacteria. Twelve bacterial isolates were screened based on their ability for their tolerance to low pH and bile salt. The isolates were identified by using 16S rRNA gene partial sequencing method. All screened isolates showed great survival percentage at low pH, that is (89.2 ± 0.75 to 97.1 ± 0.64) survived at 3 h and (83.6 ± 0.75 to 95.2 ± 0.63) at 6 h challenge at pH2. Isolate GCM112 was the least tolerant strain in 6.0% salt concentration at 12 and 24 h exposure time (82.1 ± 1.28 and 79.9 ± 1.96%) respectively. The result revealed no strain tests in this study exhibited α- and ß-hemolytic activity when cultured in sheep blood agar. Most isolated strains showed best growth at 37°C temperature and up to 4% NaCl concentration. Based on the reported result from in vitro data, GCH212 and GCM412 isolates were recognized as best potential probiotic bacteria for chicken against pathogens but further studies are needed on in vivo assessment on the health benefits in the real life situation.

The prevalence of Yersinia enterocolitica isolates in comparison to those of the commonly encountered enteropathogens causing diarrhoea among Ethiopian patients in Addis Ababa.

This cross-sectional study was designed to determine and describe the prevalence of diarrhoea caused by Yersinia enterocolitica isolates in comparison with the commonly encountered diarrhoeagenic Salmonella and Shigella among all age group out-patients of Addis Ababa, Ethiopia. Standardized bacteriological isolation and biochemical test techniques were used. Among the stool samples of 205 patients tested for bacteriological cultures, only 3 (1.5%) were positive for Yersinia enterocolitica, 22 (10.7%) for Salmonella and 12 (5.8%) for Shigella. In this study, Yersinia enterocolitica did not seem to be the main aetiological enteric pathogenic agent when compared with the well-studied diarrhoeacogenic bacteria agents like Salmonella and Shigella strains.