title: Transcriptome analysis of methicillin-resistant Staphylococcus aureus in response to stigmasterol and lupeol.
abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen with multiple antibiotic resistance that causes morbidity and mortality worldwide. Multidrug-resistant (MDR) MRSA with increased resistance to currently available antibiotics has challenged the world to develop new therapeutic agents. Stigmasterol and lupeol, from the plant Phyllanthus columnaris, exhibit antibacterial activities against MRSA. The aim of this study was to utilise next-generation sequencing (NGS) to provide further insight into the novel transcriptional response of MRSA exposed to stigmasterol and lupeol.
  
  
  
  Time-kill analysis of one MRSA reference strain (ATCC 43300) and three clinical isolates (WM3, BM1 and KJ7) for both compounds was first performed to provide the bacteriostatic/bactericidal profile. Then, MRSA ATCC 43300 strain treated with both compounds was interrogated by NGS.
  
  
  
  Both stigmasterol and lupeol possessed bacteriostatic properties against all MRSA tested; however, lupeol exhibited both bacteriostatic and bactericidal properties within the same minimum inhibitory concentration and minimum bactericidal concentration values against BM1 (12.5mg/mL). Transcriptome profiling of MRSA ATCC 43300 revealed significant modulation of gene expression with multiple desirable targets by both compounds, which caused a reduction in the translation processes leading to inhibition of protein synthesis and prevention of bacterial growth.
  
  
  
  This study highlights the potential of both stigmasterol and lupeol as new promising anti-MRSA agents.
authors.affiliation: Faculty of Dentistry, Universiti Sains Islam Malaysia, Jalan Pandan Utama, 55100 Kuala Lumpur, Malaysia. Electronic address: adnaliza@usim.edu.my.
authors.forename: Siti-Noor-Adnalizawati
authors.initials: SN
authors.lastname: Adnan
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600 Selangor, Malaysia.
authors.forename: Nazlina
authors.initials: N
authors.lastname: Ibrahim
authors.affiliation: School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600 Selangor, Malaysia.
authors.forename: Wan Ahmad
authors.initials: WA
authors.lastname: Yaacob
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004338:Drug Combinations; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D008712:Methicillin / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D053978:Pentacyclic Triterpenes / Q000494:pharmacology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D054657:Ribosome Subunits / Q000235:genetics; D017421:Sequence Analysis; D013203:Staphylococcal Infections / Q000382:microbiology; D013265:Stigmasterol / Q000494:pharmacology*; D000094042:Lupanes
chemical_list: D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D008712:Methicillin; D053978:Pentacyclic Triterpenes; D012336:RNA, Ribosomal, 16S; D013265:Stigmasterol; C010480:lupeol; D000094042:Lupanes
keywords: Lupeol; MRSA; Protein synthesis; Stigmasterol; Time–kill analysis; Transcriptome profiling