Potential of Zimbabwean commercial probiotic products and strains of Lactobacillus plantarum as prophylaxis and therapy against diarrhoea caused by Escherichia coli in children.

OBJECTIVE: To evaluate the potential of commercial fermented products sold in the country, and strains of Lactobacillus plantarum (L. plantarum) as prophylaxis and therapy against diarrhoea in children.

METHODS: The antimicrobial potential of cultures of lactobacilli enriched from 4 Zimbabwean commercial food/beverage products: Dairibord Lacto sour milk (DLSM), Probrand sour milk (PSM), Kefalos Vuka cheese (KVC) and Chibuku opaque beer (COB); and four strains of L. plantarum obtained from Balkan traditional cheeses against clinical strains of Escherichia coli (E. coli) was assayed using the well diffusion method. Three commercial paediatric antidiarrhoeal drug products: Biogaia (BG), Prolife (PL) and Probio Junior (PJ) and a mutant strain of E. coli [strain 11105 (ATCC) - a vitamin B-12 auxotroph and penicillin G acylase-producing strain] were used as controls. An agar diffusion assay and a competitive exclusion assay were carried out on Mueller Hinton agar.

RESULTS: Crude cultures of putative lactobacillus strains obtained from Zimbabwean dairy products (Probrand sour milk, Kefalos Vuka vuka cheese and Chibuku opaque beer) had significantly higher antimicrobial activities against clinical strains of E. coli than strains of L. plantarum isolated from Balkan cheeses (CLP1, CLP2 or CLP3) and crude microbial cultures from commercial paediatric probiotic products (BG, PJ and PL) of a culture of Lactobacillus rhamnosus LGG (P < 0.05).

CONCLUSIONS: The putative Lactobacilli from four commercial Zimbabwean dairy products (Probrand sour milk, Kefalos Vuka vuka cheese and Chibuku opaque beer), and three strains of L. plantarum from Balkan cheeses (CLP1, CLP2 or CLP3) exhibited high antibacterial activities that can be harnessed to control paediatric diarrhoea that is caused by pathogenic strains of E. coli. Studies to characterise the probiotic potential of the live cultures in the products and the new strains of L. plantarum are underway.