African Journal of Biotechnology Vol. 6 (7), pp. 939-949, 2 April 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Evaluation of the probiotic potential of lactic acid bacteria isolated from faeces of breast-fed infants in Egypt

Rowaida Khalil^1* Hoda Mahrous², Khalil El-Halafawy², Kamal Kamaly³, Josef Frank⁴ and Morsi El Soda⁵

¹Department of Botany, Faculty of Science, Alexandria University, Egypt.

²Genetic Engineering and Biotechnology Research Institute (GEBRI), Menofiya University, Egypt.

³Department of Dairy Science and Technology, Faculty of Agriculture, Menofiya University, Egypt

⁴Department of Food Science and Technology, University of Georgia, Athens, GA 30602, USA

⁵Department of Dairy Science, Faculty of Agriculture, Alexandria University, Egypt.

*Corresponding author. E-mail: rowaida_georgia@hotmail.com. Tel: 002-3921595. Mobile: 002 0123772803. Fax: 002-3911794.

The probiotic-related characteristics of 55 strains of lactic acid bacteria isolated from the faeces of 3 - 6 months old breast-fed infants were determined. The API 50 CH and SDS-PAGE techniques were employed to ascertain the identity of the isolated strains. The predominant species among the isolated strains were Lactobacillus (Lb.) acidophilus, Lb. plantarum, Enterococcus (E.) faecium, and E. faecalis. Probiotic properties such as bile resistance, acid tolerance, and adhesion to intestinal mucous were assessed. In vitro results obtained showed that five strains, Lb. plantarum (P1 and P164), Lb. pentosus (P191), and Lb. fermentum (P10, P193) were able to meet the basic requirements for probiotic functions as they demonstrated probiotic characteristics such as tolerance to pH 3, growth in 0.4% oxgall and adhesion to intestinal mucous. The results obtained in this investigation will be used to select potentially probiotic strains for in vivo study.

Key words: Probiotics, lactic acid bacteria, bile resistance, acid tolerance, adhesion.