Impact Of Straight Chain Fatty Acids on Staphylococcus Aureus Growth And Biofilm Production

Over the past century, the rapidly rising rates of antibiotics resistance coupled with decreased new antibiotics on the markets has led to a global health crisis. In the United States alone, antibiotics resistant infections occur over 2.5 million times each year resulting in over 35,000 deaths.¹ One bacterium of interest is Staphylococcus aureus (S. aureus) which is a gram-positive bacterium and one of the global leaders in antibiotic resistant infections and death. While S. aureus has many prominent virulence factors, one under explored area is the S. aureus’ ability to produce biofilms. Biofilms are a common bacterial mechanism in which clusters of bacteria are linked via a matrix of extracellular polymeric substances comprised of an array of biomolecules such as polysaccharides, DNA, and proteins.² One characteristic of S. aureus and many other bacteria is the uptake of exogenous free fatty acids. While this is primarily being studied on its impact to the bacterial membrane, the effect on overall bacterial growth has been less explored. As such, this study investigates the role of palmitic acid (16:0, a saturated free fatty acid) and oleic acid (18:1, a mono-unsaturated free fatty acid), two biologically prominent free fatty acids, on biofilm formation utilizing JE2, a parent strain of S. aureus. To do this, a researched protocol was modified and optimized for both increased biofilm formation and consistent results. Following the protocol optimization, varying conditions were explored such as the utilization of a fakA mutant, thought to inhibit exogenous free fatty acid incorporation, along with AFN – 1252, a potential therapeutic targeting endogenous fatty acid synthesis.³ Following this analysis, investigations into the effect on general growth trends and antibiotic resistance were explored with oleic acid along with three oleic acid derivatives following antibiotic challenging with different daptomycin concentrations to determine if potentially conferred antibiotic resistance was directly linked with oleic acid or with solely unsaturated free fatty acid incorporation. 

References 

(1) Nelson, R. E.; Hatfield, K. M.; Wolford, H.; Samore, M. H.; Scott, R. D., II; Reddy, S. C.; Olubajo, B.; Paul, P.; Jernigan, J. A.; Baggs, J. National Estimates of Healthcare Costs Associated With Multidrug-Resistant Bacterial Infections Among Hospitalized Patients in the United States. Clinical Infectious Diseases 2021, 72 (Supplement_1), S17-S26. DOI: 10.1093/cid/ciaa1581 (acccessed 4/14/2025).

(2) Karygianni, L.; Ren, Z.; Koo, H.; Thurnheer, T. Biofilm Matrixome: Extracellular Components in Structured Microbial Communities. Trends in Microbiology 2020, 28 (8), 668-681. DOI: https://doi.org/10.1016/j.tim.2020.03.016.

(3) Hafkin, B.; Kaplan, N.; Murphy, B. Efficacy and Safety of AFN-1252, the First Staphylococcus-Specific Antibacterial Agent, in the Treatment of Acute Bacterial Skin and Skin Structure Infections, Including Those in Patients with Significant Comorbidities. Antimicrob Agents Chemother 2015, 60 (3), 1695-1701. DOI: 10.1128/aac.01741-15  From NLM.