Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for high morbidity and mortality rates. Citral has been studied in the pharmaceutical industry and has shown antimicrobial activity. This study aimed to analyze the antimicrobial activity of citral in inhibiting biofilm formation and modulating virulence genes, with the ultimate goal of finding a strategy for treating infections caused by MRSA strains. Citral showed antimicrobial activity against MRSA isolates with minimum inhibitory concentration (MIC) values between 5 mg/mL (0.5%) and 40 mg/mL (4%), and minimum bactericidal concentration (MBC) values between 10 mg/mL (1%) and 40 mg/mL (4%). The sub-inhibitory dose was 2.5 mg/mL (0.25%). Citral, in an antibiogram, modulated synergistically, antagonistically, or indifferent to the different antibiotics tested. Prior to evaluating the antibiofilm effects of citral, we classified the bacteria according to their biofilm production capacity. Citral showed greater efficacy in the initial stage, and there was a significant reduction in biofilm formation compared to the mature biofilm. qPCR was used to assess the modulation of virulence factor genes, and icaA underexpression was observed in isolates 20 and 48. For icaD, seg, and sei, an increase was observed in the expression of ATCC 33,591. No significant differences were found for eta and etb. Citral could be used as a supplement to conventional antibiotics for MRSA infections.

BACKGROUND The knowledge about eicosanoid metabolism and lipid droplet (LD) formation in the Leishmania is very limited and new approaches are needed to identify which bioactive molecules are produced of them. OBJECTIVES Herein, we compared LDs and eicosanoids biogenesis in distinct Leishmania species which are etiologic agents of different clinical forms of leishmaniasis. METHODS For this, promastigotes of Leishmania amazonensis , L. braziliensis and L. infantum were stimulated with polyunsaturated fatty acids (PUFA) and LD and eicosanoid production was evaluated. We also compared mutations in structural models of human-like cyclooxygenase-2 (GP63) and prostaglandin F synthase (PGFS) proteins, as well as the levels of these enzymes in parasite cell extracts. FINDINGS PUFAs modulate the LD formation in L. braziliensis and L. infantum . Leishmania spp with equivalent tissue tropism had same protein mutations in GP63 and PGFS. No differences in GP63 production were observed among Leishmania spp, however PGFS production increased during the parasite differentiation. Stimulation with arachidonic acid resulted in elevated production of hydroxyeicosatetraenoic acids compared to prostaglandins. MAIN CONCLUSIONS Our data suggest LD formation and eicosanoid production are distinctly modulated by PUFAS dependent of Leishmania species. In addition, eicosanoid-enzyme mutations are more similar between Leishmania species with same host tropism.

Leishmania parasites contain lipid droplets (LD, or lipid bodies) and the molecular machinery responsible for synthesizing prostaglandins (PGs) and other bioactive lipids. We studied the effects of polyunsaturated fatty acids (PUFA) on LD biogenesis and eicosanoid production in distinct Leishmania species associated with different clinical forms of leishmaniasis. We also compared structural models of human-like cyclooxygenase-2 (GP63) and prostaglandin F synthase (PGFS) proteins of Leishmania, and we evaluated their enzymatic production in logarithmic and stationary growth phases of procyclic L. amazonensis, L. braziliensis and L. infantum. PUFAs modulate the formation of LDs in L. braziliensis and L. infantum. Leishmania species with equivalent clinical manifestations and tissue tropism had same protein mutations in GP63 and PGFS. No differences in GP63 production were observed among L. amazonensis, L. braziliensis and L. infantum, however increased PGFS production was detected during the parasite differentiation. Stimulation with arachidonic acid resulted in highly elevated production of hydroxyeicosatetraenoic acids compared to prostaglandins quantified by LC-MS/MS. The present findings open new perspectives on the role of eicosanoid metabolism in Leishmania and could contribute to the development of novel antiparasitic drugs.