linoleic-acid and Staphylococcal-Infections

Resistance-nodulation-division (RND) superfamily efflux pumps promote antibiotic resistance in Gram-negative pathogens, but their role in Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) is undocumented. However, recent

Topics: Animals; Anti-Bacterial Agents; Cattle; Humans; Linoleic Acid; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Staphylococcal Infections; Staphylococcus aureus

Topics: Extracellular Vesicles; Fatty Acids; HEK293 Cells; Host-Pathogen Interactions; Humans; Immunity, Innate; Linoleic Acid; Proteomics; Staphylococcal Infections; Staphylococcus aureus

Skin colonization of Staphylococcus spp. critically affects the severity of dermatitis in humans and animals. We examined different types of fatty acid salts for their antibacterial activity against Staphylococcus spp. when used in ultrapure soft water (UPSW). We also evaluated their therapeutic effect on a spontaneous canine model of dermatitis.. UPSW, in which Ca(++) and Mg(++) were replaced with Na(+) , was generated using a water softener with cation-exchange resin. Staphylococcus aureus (Staph. aureus), Staphylococcus intermedius (Staph. intermedius), and Staphylococcus pseudintermedius (Staph. pseudintermedius) were incubated with various fatty acid salts in distilled water (DW) or UPSW and the number of bacteria was counted. Among the fatty acids, oleic acid salt and linoleic acid (LA) salt reduced the number of these bacteria. Also, UPSW enhanced the antibacterial effect of LA on Staph. spp. In spontaneously developed itchy dermatitis in companion dogs, shampoo treatment with liquid soap containing 10% LA in UPSW improved skin conditions.. LA salt showed antibacterial activity against Staph. spp. Treatment with soap containing LA with UPSW reduced clinical conditions in dogs with dermatitis.. Because colonization of Staph. spp. on the skin exacerbates dermatitis, the use of LA-containing soap in UPSW may reduce unpleasant clinical symptoms of the skin.

Topics: Animals; Anti-Bacterial Agents; Dermatitis; Dog Diseases; Dogs; Linoleic Acid; Oleic Acid; Skin; Soaps; Staphylococcal Infections; Staphylococcus; Water

Although Staphylococcus aureus is exposed to antimicrobial fatty acids on the skin, in nasal secretions, and in abscesses, a specific mechanism of inducible resistance to this important facet of innate immunity has not been identified. Here, we have sequenced the genome of S. aureus USA300 variants selected for their ability to grow at an elevated concentration of linoleic acid. The fatty acid-resistant clone FAR7 had a single nucleotide polymorphism resulting in an H₁₂₁Y substitution in an uncharacterized transcriptional regulator belonging to the AcrR family, which was divergently transcribed from a gene encoding a member of the resistance-nodulation-division superfamily of multidrug efflux pumps. We named these genes farR and farE, for regulator and effector of fatty acid resistance, respectively. Several lines of evidence indicated that FarE promotes efflux of antimicrobial fatty acids and is regulated by FarR. First, expression of farE was strongly induced by arachidonic and linoleic acids in an farR-dependent manner. Second, an H₁₂₁Y substitution in FarR resulted in increased expression of farE and was alone sufficient to promote increased resistance of S. aureus to linoleic acid. Third, inactivation of farE resulted in a significant reduction in the inducible resistance of S. aureus to the bactericidal activity of 100 μM linoleic acid, increased accumulation of [(14)C]linoleic acid by growing cells, and severely impaired growth in the presence of nonbactericidal concentrations of linoleic acid. Cumulatively, these findings represent the first description of a specific mechanism of inducible resistance to antimicrobial fatty acids in a Gram-positive pathogen.. Staphylococcus aureus colonizes approximately 25% of humans and is a leading cause of human infectious morbidity and mortality. To persist on human hosts, S. aureus must have intrinsic defense mechanisms to cope with antimicrobial fatty acids, which comprise an important component of human innate defense mechanisms. We have identified a novel pair of genes, farR and farE, that constitute a dedicated regulator and effector of S. aureus resistance to linoleic and arachidonic acids, which are major fatty acids in human membrane phospholipid. Expression of farE, which encodes an efflux pump, is induced in an farR-dependent mechanism, in response to these antimicrobial fatty acids that would be encountered in a tissue abscess.

Topics: Arachidonic Acids; Bacterial Proteins; Biological Transport; Gene Expression Regulation, Bacterial; Humans; Linoleic Acid; Polymorphism, Single Nucleotide; Staphylococcal Infections; Staphylococcus aureus

Resistance to desiccation and to skin fatty acids was measured in three groups of methicillin-resistant Staphylococcus aureus (MRSA) strains and a group of control strains. Organisms from a large outbreak on a special care baby unit (SCBU), where MRSA had been isolated from staff hands but not from the environment, were significantly more sensitive to drying than strains from a burns unit where extensive environmental contamination had been demonstrated. MRSA from other wards, in the same hospital but not associated with large outbreaks, gave heterogeneous results. Fatty-acid resistance, determined by an agar dilution method, was not associated with strain origin. Some epidemic strains of MRSA were relatively sensitive to desiccation, and the abilities of such strains to spread widely on a SCBU by the hand-borne route could not be explained by enhanced resistance to skin fatty acids.

Topics: Cross Infection; Desiccation; Disease Outbreaks; Hong Kong; Humans; Infant; Infant, Newborn; Kinetics; Linoleic Acid; Linoleic Acids; Linolenic Acids; Lipase; Methicillin Resistance; Pigments, Biological; Skin; Staphylococcal Infections; Staphylococcus aureus