Effect of culture media and growth phase on the morphology of lactobacilli and on their ability to adhere to epithelial cells
Previous studies have demonstrated that the ability of lactobacilli to attach to and colonize uroepithelial surfaces is an important characteristic that enhances interference against uropathogenic bacteria. This adherence capacity was found to vary amongst lactobacillus strains and with the type of growth medium used to culture the organisms. The present study was undertaken to examine further the effect of culture media and growth phase on lactobacillus adherence to uroepithelial cells in vitro. In addition, a freeze substitution technique was developed to examine the morphology of strainsLactobacillus casei ssrhamnosus RC-17,L. casei GR-1, andL. acidophilus T-13 in relation to growth conditions and adhesion. A growth curve was plotted for strain GR-1, and adherence was found to be lowest for bacteria in early log phase (39 bacteria per uroepithelial cell) and highest in stationary phase (59 bacteria per uroepithelial cell). Strains RC-17 and GR-1 attached in high numbers to uroepithelial cells, whereas T-13 was poorly adherent. The latter formed a long, relatively dense, fibrous capsule after growth in brain heart infusion yeast extract agar, unlike strains GR-1 and RC-17, which formed a short, tightly bound, electron-dense capsule which surrounded the cells in a radial fashion. Growth of RC-17 in batch cultures of human urine, with and without addition of carbohydrates, resulted in formation of an irregular, fibrous extracellular matrix. These experiments illustrate that growth phase and culture conditions affect the extracellular structure of lactobacilli and also affect the adherence capacity of these bacteria. Structural changes mediated by availability of nutrients may partly explain why lactobacilli vary between species and between hosts in their colonization of the urogenital tract.
KeywordsLactobacillus Growth Phase Human Urine Brain Heart Infusion Lactobacillus Strain
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- 4.Cook RL, Tannock G, Meech R (1984) The microflora of the vagina. Proceedings of the University of Otago Medical School, Dunedin, New Zealand 62:72–74Google Scholar
- 5.Costerton JW, Irvin RT, Cheng K-J (1981) The role of bacterial surface structures in pathogenesis. CRC Rev 8:303–338Google Scholar
- 7.Graham LL, Costerton JW (1986) The role of bacterial exopolysaccharides in the adhesion of indigenous urethral flora to human uroepithelium. Proceedings of the 36th Annual Meeting of the Canadian Society of Microbiologists, Toronto, Canada, June 8–11. #IN 9p, p 91Google Scholar
- 10.Knox KW, Wicken AJ (1984) Environmentally induced changes in the surfaces of oral streptococci and lactobacilli. Proc. ASM Workshop, Molecular basis of oral microbial adhesion, Philadelphia, PA, June 5–8, pp 212–219Google Scholar
- 13.Reid G, Brooks HJL (1984) In vitro attachment ofE. coli to human epithelial cells. NZ Med J 97:439–442Google Scholar
- 18.Reid G, Zorzitto ML, Bruce AW, Jewett MAS, Chan RCY, Costerton JW (1984) Pathogenesis of urinary tract infection in the elderly: the role of bacterial adherence to uroepithelial cells. Curr Microbiol 11:67–72Google Scholar
- 19.Reid G, Cook RL, Angotti R, Adre JK, Bruce AW (1987) Bacterial interference and the role ofLactobacillus spp. in preventing recurrent urinary tract infection. In: Murakami K, Kitagawa T, Yabuta, K, Sakai T (eds), Recent advances in pediatric nephrology. Amsterdam, Holland: Excerpta Medica ICS 733:265–270Google Scholar
- 21.Rogosa M (1970) Characters used in the classification of lactobacilli. Int J Syst Bacteriol 20:519–533Google Scholar
- 23.Sharpe E (1981) The genus Lactobacillus. In: The prokaryotes, a handbook on habitats, isolation, and identification of bacteria. New York: Springer Verlag, vol 2, chap 131, pp 1654–1679Google Scholar