article · AFRICAN JOURNAL OF BIOTECHNOLOGY
Lactic acid bacteria isolated from traditional fermented Shamita and Kocho were assessed in vitro for desirable probiotic characteristics. From sixteen collected samples, 140 bacterial isolates were obtained, of which 101 demonstrated antimicrobial activity against Shigella boydii or Salmonella typhimurium. Further screening showed that 36 isolates survived exposure to 0.3 percent bile salts, and 30 of these also displayed strong tolerance to acidic conditions across several hours. Phenotypic identification classified these 30 strains into the genera Lactobacillus, Leuconostoc, Pediococcus, and Lactococcus. Testing for antibiotic susceptibility revealed universal resistance to oxacillin and complete sensitivity to erythromycin and gentamicin, alongside two multidrug-resistant strains. Ultimately, nine isolates were selected as promising probiotic candidates for subsequent evaluation in fermented food formulations.
Probiotics support gut health and protect against harmful pathogens, but candidate microbes must survive the harsh acid and bile barriers of the digestive tract. Demonstrating that traditional fermented products harbour robust, acid-tolerant lactic acid bacteria helps establish regional fermented foods as valuable resources for discovering functional microbial strains for human consumption.
The work could enable food processors and dairy manufacturers to formulate functional probiotic products or starter cultures using locally adapted strains. As early-stage in vitro research, the isolates remain several steps from commercial application. Realising market use will require strain safety profiling to address antibiotic resistance traits, in vivo health validation, and pilot-scale fermentation testing.
AI-generated from the published abstract. Always read the original work before citing.
The study was conducted to evaluate in vitro probiotic properties of lactic acid bacteria (LAB) isolated from fermented Shamita and Kocho. Sixteen samples, 8 each of Shamita and Kocho, were collected from Arat-Kilo and Merkato sites in Addis Ababa, respectively. The average pH values of Shamita and Kocho samples were 3.52 and 3.44, respectively. A total of 140 LAB were isolated, of which 101 isolates (72%) were found to inhibit one or more of the sensitive test organisms Shigella boydii and Salmonella typhimurium but none of them had antimicrobial activity against Staphylococcus aureus. The inhibition diameters on agar medium ranged from 8.5 to 17.5 mm. The 101 isolates having antagonistic effects against the test organisms were evaluated for their bile tolerance. Thirty six isolates (36%) tolerated 0.3% bile salts for 48 h with 55 to 93% survival. The 36 bile tolerant isolates were evaluated for their acid tolerance and 25 (69%), 30 (83%) and 34 (94%) tolerated pH 2, pH 2.5 and pH 3 for 3 h, respectively. Further extension of the incubation period for 6 h reduced the number of isolates to 21 (58%) and 33 (92%) at pH 2 and pH 3. Thirty of the bile tolerant isolates (83%) showed 80 to 94% survival at pH 2.5 for 6 h. These isolates were selected as LAB candidates with probiotic potential. Based on their phenotypic characteristics, the 30 isolates were identified as Lactobacillus (17 isolates), Leuconostoc (6 isolates) and Pediococcus (4 isolates) and Lactococcus (3 isolates). Antibiotic resistance patterns of the 30 isolates showed 100% resistance against oxacillin but lower resistance to levofloxacin; 57% of the isolates were resistant to penicillin. However, all the isolates were sensitive to erythromycin and gentamicin. Multiple drug resistance patterns were observed in two isolates one each from Shamita Lactobacillus (S9) and Kocho Lactobacillus (K64) having multiple resistances to penicillin, levofloxacin and oxacillin. Nine isolates (30%) were selected as probiotic candidates for further test on different fermented foods. Key words: Lactic acid bacteria; Lactobacillus, Leuconostoc, Pediococcus, Lactococcus spp., acid tolerance, antimicrobial activity, bile tolerance.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.5897/ajb2016.15307
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
