Antimicrobial and Antibiofilm Activity of Monolaurin against Methicillin-Resistant Staphylococcus aureus Isolated from Wound Infections

Abstract

Background. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major pathogens associated with life-threatening infections, showing resistance to various antibiotics. Tis study aimed to assess the infuence of monolaurin on bioflm-forming MRSA. Methods. Te agar dilution method determined the minimum inhibitory concentration (MIC) of monolaurin against MRSA isolates and explored its impact on the resistance profle of selected antibiotics. Te assessment of combined therapy involving monolaurin and antibiotics was conducted using fractional inhibitory concentration (FIC). Te tissue culture plate strategy appraised monolaurin’s antibioflm activity and its inhibitory concentration (IC50), with assessment via scanning electron microscopy. Reverse transcription polymerase chain reaction (RT-PCR) discerned a monolaurin efect on the expression of the icaD gene. Results. Monolaurin exhibited MIC values ranging from 500 to 2000 μg/mL. FIC index showed a synergistic efect of monolaurin with β-lactam antibiotics ranging from 0.0039 to 0.25 (p < 0.001). Among the 103 investigated MRSA isolates, 44 (44.7%) displayed moderate bioflm formation, while 59 (55.3%) were strong bioflm producers. Antibioflm activity demonstrated concentration dependence, confrming monolaurin’s capacity to inhibit bioflm formation and exhibited strong eradicating efects against preformed MRSA bioflms with IC50 values of 203.6 μg/mL and 379.3 μg/mL, respectively. Scanning electron microscope analysis revealed reduced cell attachments and diminished bioflm formation compared to the control. Te expression levels of the icaD gene were remarkably reduced at monolaurin concentrations of 250 and 500 μg/mL. Conclusion. Monolaurin had signifcant inhibitory efects on MRSA pre-existing bioflms as well as bioflm development. So, it can be employed in the treatment of severe infections, particularly those associated with bioflm formation including catheter-associated infections.