Identification of a Small Molecule Anti-biofilm Agent Against Salmonella enterica

Abstract

Biofilm formation is a common strategy utilized by bacterial pathogens to establish persistence in a host niche. Salmonella enterica serovar Typhi, the etiological agent of Typhoid fever, relies on biofilm formation in the gallbladder to chronically colonize asymptomatic carriers, allowing for transmission to uninfected individuals. S. enterica serovar Typhimurium utilizes biofilms to achieve persistence in human and animal hosts, an issue of both clinical and agricultural importance. Here, we identify a compound that selectively inhibits biofilm formation in both S. Typhi and S. Typhimurium serovars at early stages of biofilm development with an EC50 of 21.0 and 7.4 μM, respectively. We find that this compound, T315, also reduces biofilm formation in Acinetobacter baumannii, a nosocomial and opportunistic pathogen with rising antibiotic resistance. T315 treatment in conjunction with sub-MIC dosing of ciprofloxacin further reduces S. enterica biofilm formation, demonstrating the potential of such combination therapies for therapeutic development. Through synthesis of two biotin-labeled T315 probes and subsequent pull-down and proteomics analysis, we identified a T315 binding target: WrbA, a flavin mononucleotide-dependent NADH:quinone oxidoreductase. Using a S. Typhimurium strain lacking WrbA we demonstrate that this factor contributes to endogenous S. enterica biofilm formation processes and is required for full T315 anti-biofilm activity. We suggest WrbA as a promising target for further development of anti-biofilm agents in Salmonella, with potential for use against additional bacterial pathogens. The development of anti-biofilm therapeutics will be essential to combat chronic carriage of Typhoid fever and thus accomplish a meaningful reduction of global disease burden.

Human Pleural Fluid and Human Serum Albumin Modulate the Behavior of a Hypervirulent and Multidrug-Resistant (MDR) Acinetobacter baumannii Representative Strain

“…Other genes down-regulated in the presence of HPF were wrbA , pspC and motA . The wrbA and pspC genes code for stress regulators [ 54 , 55 ], and motA is a gene essential for motility [ 56 ] ( Figure S6A ). Addition of HSA was associated with reduced expression of katE and ywrO, which code for a catalase and a general stress protein, respectively [ 57 ].…”

Inhibition of Bacterial Biofilm Formation

“…Furthermore, T315, an integrin-linked kinase inhibitor previously identified as a potential therapeutic agent against chronic lymphocytic leukemia [32], was shown to selectively inhibit biofilm formation in both Salmonella typhi and Salmonella Typhimurium at early stages of biofilm development without affecting bacterial viability. T315 was also demonstrated to reduce biofilm formation in Acinetobacter baumannii but had no effect on P. aeruginosa suggesting a bacterial specificity [33].…”

Controlling foodborne pathogens with natural antimicrobials by biological control and antivirulence strategies

“… Antivirulent Agent ∗ Foodborne pathogen Activity Reference Probiotics Bifidobacterium lactis Bb12 / Lactobacillus rhamnosus LGG Salmonella Typhimurium Enteropathogenic E. coli Anti-adhesive ( Bernet et al., 1994 ) L. acidophilus A4 E. coli O157:H7 Anti-adhesive ( Kim et al., 2008 ) E. coli Nissle S . Typhimurium Anti-invasive ( Altenhoefer et al., 2004 ) Bifidobacteria Shiga toxin-producing E. coli Antitoxin effect ( Asahara et al., 2004 ) Bifidobacteria and lactobacilli Clostridium difficile Antitoxin effect ( Valdés-Varela et al., 2016 ) L. acidophilus A4 E. coli O157:H7 Antibiofilm ( Kim et al., 2009 ) L. acidophilus La-5 E. coli O157:H7 Anti-quorum sensing ( Medellin-Pena et al., 2007 ) Probiotic Bacillus subtilis Staphylococcus aureus Decolonization ( Piewngam et al., 2018 ) Chemical or biological molecules T315 compound S. Typhimurium Antibiofilm ( Moshiri et al., 2018 ) Chalcone S. aureus Anti-toxin Anti-QS Antibiofilm ( Zhang et al., 2017 ) Carvacrol, thymol, trans-cinnamaldehyde E. coli O157:H7 Antibiofilm Reduced expression of virulence genes …”