Fatty acids and monoacylglycerols inhibit growth ofStaphylococcus aureus

Abstract

Staphylococcus aureus causes a variety of human infections including toxic shock syndrome, osteomyelitis, and mastitis. Mastitis is a common disease in the dairy cow, and S. aureus has been found to be a major infectious organism causing mastitis. The objectives of this research were to determine which FA and esterified forms of FA were inhibitory to growth of S. aureus bacteria. FA as well as their mono-, di-, and triacylglycerol forms were tested for their ability to inhibit a human toxic shock syndrome clinical isolate (MN8) and two S. aureus clinical bovine mastitis isolates (305 and Novel). The seven most potent inhibitors across all strains tested by minimum inhibitory concentration analysis included lauric acid, glycerol monolaurate, capric acid, myristic acid, linoleic acid, cis-9, trans-11 conjugated linoleic acid, and trans-10, cis-12 conjugated linoleic acid. Some of these lipids were chosen for 48-h growth curve analysis with a bovine mastitis S. aureus isolate (Novel) at doses of 0, 20, 50, and 100 microg/mL except myristic acid, which was tested at 0, 50, 100, and 200 microg/mL. The saturated FA (lauric, capric, myristic) and glycerol monolaurate behaved similarly and reduced overall growth. In contrast, the polyunsaturated FA (linoleic and cis-9, trans-11 conjugated linoleic acid) delayed the time to initiation of exponential growth in a dose-dependent fashion. The results suggest that lipids may be important in the control of S. aureus during an infection.

Quantitative structure-activity relationships of antimicrobial fatty acids and derivatives against Staphylococcus aureus

“…This is in good agreement with previous studies in which Kabara et al (1977) and Kelsey et al (2006) showed that medium-chain saturated fatty acids and long-chain unsaturated fatty acids were potent antimicrobials against bacteria, especially Gram-positive bacteria. Monoglycerides were the most active derivatives and were usually more potent than their corresponding fatty acids.…”

“…It was previously reported (Kabara et al, 1977) that monotridecanoin showed no activity against S. aureus. Cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acids showed no activity in this study, which was not consistent with Kelsey et al (2006). This may be due to the different sensitivity of S. aureus strains to certain lipids.…”

“…Fatty acids and derivatives (FADs) are one group of chemicals found in nature and are considered to have little or no toxicity in low concentrations. They have been proven to exert antimicrobial activity and have attracted much attention during the past 40 years (Bergsson et al, 2001;Kelsey et al, 2006;Habulin et al, 2008).…”

Effect of Prostaglandin F2α on Growth of Staphylococcus Aureus Associated with Bovine Mastitis

“…Plate counts were done in triplicate per sample from each flask. Plates were incubated at least 12 h, or until colonies were apparent, at a constant temperature of 37°C [17].…”

“…Hogan et al [15] showed that long chain fatty acids (C12, C14, Polyene C18:2 and C18:3) have bacteriostatic and bactericidal effects on S. aureus and Strep. agalactiae Our laboratory [17] demonstrated that linoleic acid inhibited growth of two different mastitis strains of S. aureus. Interestingly, fatty acids can also be metabolized into various products which can also inhibit bacterial growth.…”