title: Antibacterial properties of 3-(phenylsulfonyl)-2-pyrazinecarbonitrile.
abstract: The emergence of multidrug-resistant bacterial strains has heightened the need for new antimicrobial agents based on novel chemical scaffolds that are able to circumvent current modes of resistance. We recently developed a whole-animal drug-screening methodology in pursuit of this goal and now report the discovery of 3-(phenylsulfonyl)-2-pyrazinecarbonitrile (PSPC) as a novel antibacterial effective against resistant nosocomial pathogens. The minimum inhibitory concentrations (MIC) of PSPC against Staphylococcus aureus and Enterococcus faecium were 4 μg/mL and 8 μg/mL, respectively, whereas the MICs were higher against the Gram-negative bacteria Klebsiella pneumoniae (64 μg/mL), Acinetobacter baumannii (32 μg/mL), Pseudomonas aeruginosa (>64 μg/mL), and Enterobacter spp. (>64 μg/mL). However, co-treatment of PSPC with the efflux pump inhibitor phenylalanine arginyl β-naphthylamide (PAβN) or with sub-inhibitory concentrations of the lipopeptide antibiotic polymyxin B reduced the MICs of PSPC against the Gram-negative strains by >4-fold. A sulfide analog of PSPC (PSPC-1S) showed no antibacterial activity, whereas the sulfoxide analog (PSPC-6S) showed identical activity as PSPC across all strains, confirming structure-dependent activity for PSPC and suggesting a target-based mechanism of action. PSPC displayed dose dependent toxicity to both Caenorhabditis elegans and HEK-293 mammalian cells, culminating with a survival rate of 16% (100 μg/mL) and 8.5% (64 μg/mL), respectively, at the maximum tested concentration. However, PSPC did not result in hemolysis of erythrocytes, even at a concentration of 64 μg/mL. Together these results support PSPC as a new chemotype suitable for further development of new antibiotics against Gram-positive and Gram-negative bacteria.
authors.affiliation: Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School of Brown University, POB, 3rd Floor, Suite 328/330, 593 Eddy Street, Providence, RI 02903, USA; Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Rajmohan
authors.initials: R
authors.lastname: Rajamuthiah
authors.affiliation: Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School of Brown University, POB, 3rd Floor, Suite 328/330, 593 Eddy Street, Providence, RI 02903, USA; Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Elamparithi
authors.initials: E
authors.lastname: Jayamani
authors.affiliation: Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW 2522, Australia; School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: Hiwa
authors.initials: H
authors.lastname: Majed
authors.affiliation: Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Annie L
authors.initials: AL
authors.lastname: Conery
authors.affiliation: Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School of Brown University, POB, 3rd Floor, Suite 328/330, 593 Eddy Street, Providence, RI 02903, USA.
authors.forename: Wooseong
authors.initials: W
authors.lastname: Kim
authors.affiliation: Division of Neurology, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, RI 02903, USA.
authors.forename: Bumsup
authors.initials: B
authors.lastname: Kwon
authors.affiliation: Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School of Brown University, POB, 3rd Floor, Suite 328/330, 593 Eddy Street, Providence, RI 02903, USA.
authors.forename: Beth Burgwyn
authors.initials: BB
authors.lastname: Fuchs
authors.affiliation: Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW 2522, Australia; School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kelso
authors.affiliation: Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Frederick M
authors.initials: FM
authors.lastname: Ausubel
authors.affiliation: Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School of Brown University, POB, 3rd Floor, Suite 328/330, 593 Eddy Street, Providence, RI 02903, USA; Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. Electronic address: emylonakis@lifespan.org.
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Mylonakis
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017173:Caenorhabditis elegans; D004151:Dipeptides / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D057809:HEK293 Cells; D057166:High-Throughput Screening Assays; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D011112:Polymyxin B / Q000494:pharmacology; D011719:Pyrazines / Q000097:blood / Q000494:pharmacology*; D012756:Sheep; D014640:Vancomycin / Q000494:pharmacology
chemical_list: C000609113:3-(phenylsulfonyl)-2-pyrazinecarbonitrile; D000900:Anti-Bacterial Agents; D004151:Dipeptides; D011719:Pyrazines; C419365:phenylalanine arginine beta-naphthylamide; D014640:Vancomycin; D011112:Polymyxin B
keywords: C. elegans; ESKAPE; Efflux pump inhibition; High throughput screening; Liquid infection assay; MRSA; Staphylococcus aureus; Synergism