• 1.

    Hyslop NS. Dermatophilosis (streptothricosis) in animals and man. Comp Immunol Microbiol Infect Dis 1979; 2:389404.

  • 2.

    Zaria LT. Dermatophilus congolensis infection (dermatophilosis) in animals and man! An update. Comp Immunol Microbiol Infect Dis 1993; 16:179222.

    • Search Google Scholar
    • Export Citation
  • 3.

    Pascoe RR. Further observations on Dermatophilus congolensis in horses. Aust Vet J 1972; 48:3234.

  • 4.

    Furuya EY, Lowey FD. Antimicrobial-resistant bacteria in the community setting. Natl Rev 2006; 4:3645.

  • 5.

    Adamson PJ, Wilson WD, Hirsh DC, et al. Susceptibility of equine bacterial isolates to antimicrobial agents. Am J Vet Res 1985; 46:447450.

    • Search Google Scholar
    • Export Citation
  • 6.

    Jensen RG. The composition of bovine milk lipids. J Dairy Sci 2002; 85:295350.

  • 7.

    Jensen RG, Ferris AM, Lammi-Keefe CJ, et al. Lipids of bovine and human milks: a comparison. J Dairy Sci 1990; 73:223240.

  • 8.

    Caprylic acid. 21 CFR 184.1025.

  • 9.

    Kollanoor A, Vasudevan P, Nair MKM, et al. Inactivation of bacterial fish pathogens by medium-chain lipid molecules (caprylic acid, monocaprylin and sodium caprylate). Aquacult Res 2007; 38:12931300.

    • Search Google Scholar
    • Export Citation
  • 10.

    Annamalai T, Nair MKM, Marek P, et al. In vitro inactivation of enterohemorrhagic Escherichia coli O157:H7 in bovine rumen fluid by caprylic acid. J Food Prot 2004; 67:884888.

    • Search Google Scholar
    • Export Citation
  • 11.

    Nair MKM, Vasudevan P, Hoagland T, et al. Inactivation of Escherichia coli O157:H7 and Listeria monocytogenes in milk by caprylic acid and monocaprylin. Food Microbiol 2004; 21:611616.

    • Search Google Scholar
    • Export Citation
  • 12.

    Andrews JM. Determination of minimum inhibitory concentrations. Antimicrob Chemother 2001; 48(suppl 1):516.

  • 13.

    Bergsson G, Steingrimsson O, Thormar H. Bactericidal effects of fatty acids and monoglycerides on Helicobacter pylori. Int J Antimicrob Agents 2002; 20:258262.

    • Search Google Scholar
    • Export Citation
  • 14.

    Jordan D, Venning CM. Treatment of ovine dermatophilus with long-acting oxytetracycline or a lincomycin-spectinomycin combination. Aust Vet J 1995; 72:234236.

    • Search Google Scholar
    • Export Citation
  • 15.

    Krüger B, Siesenop U, Böhm KH. Phenotypic characterization of equine Dermatophilus congolensis field isolates. Berl Munch Tierarztl Wochenschr 1998; 111:374378.

    • Search Google Scholar
    • Export Citation
  • 16.

    Bergsson G, Steingrimsson O, Thormar H. In vitro susceptibilities of Neisseria gonorrhoeae to fatty acids and monoglycerides. Antimicrob Agents Chemother 1999; 43:27902792.

    • Search Google Scholar
    • Export Citation
  • 17.

    Projan SJ, Brown-Skrobt S, Schlievert PM, et al. Glycerol monolaurate inhibits the production of β-lactamase, toxic shock syndrome toxin-1, and other staphylococcal exoproteins by interfering with signal transduction. J Bacteriol 1994; 176:42044209.

    • Search Google Scholar
    • Export Citation
  • 18.

    Shibasaki I, Kato N. Combined effects on antibacterial activity of fatty acids and their esters against gram-negative bacteria. In: Kabara J, ed. The pharmacological effects of lipids. St Louis: American Oil Chemists Society, 1978;1524.

    • Search Google Scholar
    • Export Citation
  • 19.

    Sun CQ, O'Conner CJ, Roberton CJ. The antimicrobial properties of milk fat after partial hydrolysis of calf pregastric lipase. Chem Biol Interact 2002; 140:185198.

    • Search Google Scholar
    • Export Citation
  • 20.

    Viegas CA, Sa-Correia L. Activation of plasma membrane ATPase of Saccharomyces cervisiae by octanoic acid. J Gen Microbiol 1991; 137:645651.

    • Search Google Scholar
    • Export Citation
  • 21.

    Isaacs CE, Litov RE, Thormar H. Antimicrobial activity of lipids added to human milk, infant formula, and bovine milk. J Nutr Biochem 1995; 6:362366.

    • Search Google Scholar
    • Export Citation
  • 22.

    Nair MK, Vasudevan P, Venkitanarayanan K. Antibacterial effect of caprylic acid and monocaprylin on major bacterial mastitis pathogens. J Dairy Sci 2005; 88:34883495.

    • Search Google Scholar
    • Export Citation
  • 23.

    Amalaradjou MA, Annamali T, Marek P, et al. Inactivation of E.coli 0157H7 in cattle drinking water by sodium caprylate. J Food Prot 2006; 69:22482252.

    • Search Google Scholar
    • Export Citation

Advertisement

In vitro antimicrobial properties of caprylic acid, monocaprylin, and sodium caprylate against Dermatophilus congolensis

View More View Less
  • 1 Department of Animal Science, College of Agriculture and Natural Resources, University of Connecticut, Storrs, CT 06269.
  • | 2 Department of Animal Science, College of Agriculture and Natural Resources, University of Connecticut, Storrs, CT 06269.
  • | 3 Department of Animal Science, College of Agriculture and Natural Resources, University of Connecticut, Storrs, CT 06269.
  • | 4 Department of Animal Science, College of Agriculture and Natural Resources, University of Connecticut, Storrs, CT 06269.
  • | 5 Department of Animal Science, College of Agriculture and Natural Resources, University of Connecticut, Storrs, CT 06269.

Abstract

Objective—To determine antimicrobial effects of caprylic acid and its derivatives, monocaprylin and sodium caprylate, on Dermatophilus congolensis and to determine effects of caprylic acid on the ultrastructure of D congolensis by use of transmission electron microscopy (TEM).

Sample—3 strains of D congolensis (33411, 33413, and 14639).

Procedures—Strains of D congolensis were incubated separately under anaerobic conditions at 37°C for up to 48 hours in brain heart infusion (BHI) broth that was supplemented with various concentrations of caprylic acid (7.5, 12.5, 15, 17.5, or 20mM), monocaprylin (2.5, 5, 7.5, or 10mM), or sodium caprylate (15, 50, 60, 70, 100, or 120mM) or contained no antimicrobial treatment. After incubation, bacterial counts were determined by means of plating in triplicate on BHI-agar plates. Caprylic acid-treated or untreated D congolensis samples were embedded in epoxide resin for TEM; cross sections were examined for structural damage.

Results—Minimum inhibitory concentrations of caprylic acid, monocaprylin, and sodium caprylate against D congolensis were 7.5, 2.5, and 15mM, respectively. Minimum bactericidal concentrations of caprylic acid, monocaprylin, and sodium caprylate against D congolensis were 15, 5, and 70mM, respectively. Examination via TEM revealed that a 15-mM concentration of caprylic acid disintegrated the plasma membrane of D congolensis.

Conclusions and Clinical Relevance—Results indicated that caprylic acid, monocaprylin, and sodium caprylate could potentially be used to treat D congolensis infections. However, in vivo studies should be undertaken to determine whether these compounds can be considered as treatment options.

Abstract

Objective—To determine antimicrobial effects of caprylic acid and its derivatives, monocaprylin and sodium caprylate, on Dermatophilus congolensis and to determine effects of caprylic acid on the ultrastructure of D congolensis by use of transmission electron microscopy (TEM).

Sample—3 strains of D congolensis (33411, 33413, and 14639).

Procedures—Strains of D congolensis were incubated separately under anaerobic conditions at 37°C for up to 48 hours in brain heart infusion (BHI) broth that was supplemented with various concentrations of caprylic acid (7.5, 12.5, 15, 17.5, or 20mM), monocaprylin (2.5, 5, 7.5, or 10mM), or sodium caprylate (15, 50, 60, 70, 100, or 120mM) or contained no antimicrobial treatment. After incubation, bacterial counts were determined by means of plating in triplicate on BHI-agar plates. Caprylic acid-treated or untreated D congolensis samples were embedded in epoxide resin for TEM; cross sections were examined for structural damage.

Results—Minimum inhibitory concentrations of caprylic acid, monocaprylin, and sodium caprylate against D congolensis were 7.5, 2.5, and 15mM, respectively. Minimum bactericidal concentrations of caprylic acid, monocaprylin, and sodium caprylate against D congolensis were 15, 5, and 70mM, respectively. Examination via TEM revealed that a 15-mM concentration of caprylic acid disintegrated the plasma membrane of D congolensis.

Conclusions and Clinical Relevance—Results indicated that caprylic acid, monocaprylin, and sodium caprylate could potentially be used to treat D congolensis infections. However, in vivo studies should be undertaken to determine whether these compounds can be considered as treatment options.

Contributor Notes

Address correspondence to Dr. Nadeau (jenifer.nadeau@uconn.edu).