Comparison of contact angles and adhesion to hexadecane of urogenital, dairy, and poultry lactobacilli: effect of serial culture passages

Abstract

The aim of this study was to examine the hydrophobicities of 23 urogenital, dairy, poultry, and American Type Culture Collection isolates of lactobacilli and to determine the effect on hydrophobicity of serially passaging the strains in liquid medium. To this end, strains were grown after isolation and identification and then serially passaged up to 20 times. Hydrophobicity was assessed through contact angle measurements on lawns of cells by using water, formamide, methylene iodide, 1-bromonaphthalene, and hexadecane as wetting agents and through measurement of their partitioning in a hexadecane-water system. The hydrophobicities of these strains varied widely, with Lactobacillus casei strains being predominantly hydrophilic and L. acidophilus strains being mostly hydrophobic. For some isolates, serial passaging was accompanied by a clear loss of hydrophobic surface properties, whereas for other strains, cultures became heterogeneous in that some cells had already lost their hydrophobic surface properties while others were still hydrophobic. Adhesion of this collection of lactobacilli to hexadecane droplets in microbial adhesion to hexadecane (MATH) tests was driven by their aversion to water rather than by their affinity for hexadecane, as concluded from the fact that hexadecane contact angles were zero for all strains. Furthermore, adhesion of the lactobacilli to hexadecane in MATH tests occurred only when the water contact angle on the cells was above 60 degrees.

Probiotic L actobacillus rhamnosus GR ‐1 and L actobacillus reuteri RC ‐14 exhibit strong antifungal effects against vulvovaginal candidiasis‐causing C andida glabrata isolates

“…reuteri RC-14 is indeed a hydrophobic probiotic strain, whereas Lact. rhamnosus GR-1 is a hydrophilic strain (Reid et al 1992).…”

Physico-chemistry of initial microbial adhesive interactions – its mechanisms and methods for study

“…Microorganisms are always fully wettable, i.e. have a 0-³ water contact angle, immediately after removal from an aqueous phase [67,77], although microbial plateau contact angles with water as high as 90³ have been reported after drying [93,166]. Hence, it can be concluded from Fig.…”

Microbial adhesion to hydrocarbons: twenty-five years of doing MATH

“…Unfortunately, some subsequent key papers testing the validity of MATH ignored this important point and employed instead buffer of very low ionic strength (e.g. Reid et al, 1992). Under such conditions, hydrophobic interactions play less of a role and electrostatic interactions increase.…”