Facultative anaerobic lactobacilli were recovered from the vaginas of 96.8% of 63 nonpregnant, healthy, premenopausal women. The predominant species were Lactobacillus jensenii, Lactobacillus acidophilus, and Lactobacillus casei. Of the women, 74.6% had hydrogen peroxide-producing lactobacilli, 22.2% had non-hydrogen peroxide-producing lactobacilli, and 3.2% had no lactobacilli. None of the 68 isolates had catalase activity. Some 68.2% of the isolates were inhibited by concentrations of less than or equal to 1% (wt/vol) of nonoxynol-9 (bactericidal for 73.3% of isolates, bacteriostatic for 26.7%). The remaining 31.8% could grow in all concentrations to 25% (wt/vol) of nonoxynol-9. All of the lactobacilli that were sensitive to nonoxynol-9 produced hydrogen peroxide whereas only 3 of 21 resistant strains were hydrogen peroxide producers. A significant correlation (P less than .001, chi 2 test) was found between hydrogen peroxide production and sensitivity to nonoxynol-9. It is suggested that the vaginal flora of spermicide users could be depleted of hydrogen peroxide-producing lactobacilli, possibly increasing susceptibility to urogenital infection.
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.
It was hypothesized that Lactobucillus acidophilus might not be the dominant aerobic or microaerophilic Luctobacillus species in the human vagina, and that the dominant isolates are likely to express a variety of properties associated with colonization. To examine the question, vaginal swabs were collected from 100 healthy premenopausal women and cultured to detect the dominant aerobic or microaerophilic isolates of Imtobacillus. Only eight species were detected, withLuctobacillus jensenii blaing the dominant colonizers in the highest number (35) of women. Twelve different plasmid profiles were found amongst the isolates, but there was no association between plasmids and vaginal colonization or hydrogen peroxide production. Of the strains tested, few were resistant to the spermicidal agent noaoxynol-9. The data identify species within which strains may possess properties associated with maintenance of a healthy vaginal ecology
Seven clinical isolates of lactobacilli were found to be relatively hydrophobic with a mean watercontact angle of 66 ± 15 degrees, and to be susceptible to 1% nonoxynol‐9 and vancomycin. However, seven other strains were relatively hydrophilic with a mean water‐contact angle of 32 ± 13 degrees, and found to be resistant to 25% nonoxynol‐9 and vancomycin. Thus, the surface properties of lactobacilli that influence susceptibility to antimicrobial agents may involve surface hydrophobicity. Possibly the penetration barrier posed by the cell surface towards these two non‐ionic antimicrobials is lower for hydrophobic cells than for hydrophilic cells.
Seven clinical isolates of lactobacilli were found to be relatively hydrophobic with a mean water-contact angle of 66 +/- 15 degrees, and to be susceptible to 1% nonoxynol-9 and vancomycin. However, seven other strains were relatively hydrophilic with a mean water-contact angle of 32 +/- 13 degrees, and found to be resistant to 25% nonoxynol-9 and vancomycin. Thus, the surface properties of lactobacilli that influence susceptibility to antimicrobial agents may involve surface hydrophobicity. Possibly the penetration barrier posed by the cell surface towards these two nonionic antimicrobials is lower for hydrophobic cells than for hydrophilic cells.
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