Tryptone-stabilized silver nanoparticles’ potential to mitigate planktonic and biofilm growth forms of Serratia marcescens

Abstract

Several microbial pathogens are capable of forming biofilms. These microbial communities pose a serious challenge to the healthcare sector as they are quite difficult to combat. Given the challenges associated with the antibiotic-based management of biofilms, the research focus has now been shifted towards finding alternate treatment strategies that can replace or complement the antibacterial properties of antibiotics. The field of nanotechnology offers several novel and revolutionary approaches to eradicate biofilm-forming microbes. In this study, we evaluated the antibacterial and antibiofilm efficacy of in-house synthesized, tryptone-stabilized silver nanoparticles (Ts-AgNPs) against the superbug Serratia marcescens . The nanoparticles were of spherical morphology with an average hydrodynamic diameter of 170 nm and considerable colloidal stability with a Zeta potential of − 24 ± 6.15 mV. Ts-AgNPs showed strong antibacterial activities with a minimum inhibitory concentration (MIC 50 ) of 2.5 µg/mL and minimum bactericidal concentration (MBC) of 12.5 µg/mL against S. marcescens . The nanoparticles altered the cell surface hydrophobicity and inhibited biofilm formation. The Ts-AgNPs were also effective in distorting pre-existing biofilms by degrading the extracellular DNA (eDNA) component of the extracellular polymeric substance (EPS) layer. Furthermore, reduction in quorum-sensing (QS)-induced virulence factors produced by S. marcescens indicated that Ts-AgNPs attenuated the QS pathway. Together, these findings suggest that Ts-AgNPs are an important anti-planktonic and antibiofilm agent that can be explored for both the prevention and treatment of infections caused by S. marcescens . Graphical abstract Supplementary Information The online version contains supplementary material available at 10.1007/s00775-022-01977-w.

Exploring the efficacy of tryptone-stabilized silver nanoparticles against respiratory tract infection-causing bacteria: a study on planktonic and biofilm forms

“…Minimum bactericidal concentration is the concentration at which the antimicrobial agent reduces the viability of the initial bacterial inoculum by a predetermined reduction. For this, the treated cell cultures were incubated with fresh media after 24 h of incubation with Ts-AgNPs and the viability was confirmed using the MTT assay [53,54].…”

“…Bacterial cells were treated with increasing concentration of Ts-AgNPs (0-15 µg ml −1 ) and incubated for 24 h. After incubation, the tubes were further diluted to 10 6 cells and 100 µl of the diluted culture was spread on GM3 agar plates. The plates were incubated at 37 • C for 24 h and the colonies were counted and compared with untreated control which serve as negative control [54,56].…”

“…Solution A contained 3 mg of p-NPP in 1 ml of isopropanol and solution B contained 10 mg of gum arabicum, 40 µl of Triton X-100 in 9 ml of 50 mM of Tris-HCl buffer of pH 8.0. After incubation for 20 min at 60 • C in water bath, lipase activity was quantified spectrophotometrically at 410 nm [54,71].…”

Comparative analysis of the physicochemical and anti-biofilm properties of iota and lambda carrageenan-capped silver nanocomposites synthesized using response surface methodology

“…12,[16][17][18][19][20][21] Silver nanoparticles coated with different polymers such as tryptone, polyphenols, PVP, PEI, chitosan, and heparin have been utilized to inhibit biofilm growth and eradicate mature biofilms. [22][23][24][25] Moreover, silver nanoparticleloaded nanocomposites, such as nanofibers and injectable hydrogels, have demonstrated effective control over biofilm growth and eradication of established biofilms. 25,26 Carrageenan, among all the carbohydrates, is a hydrophilic, sulfated, anionic linear polysaccharide comprised of D-galactose and 3,6-anhydro-D-galactose disaccharide units alternatively.…”

“…12,16–21 Silver nanoparticles coated with different polymers such as tryptone, polyphenols, PVP, PEI, chitosan, and heparin have been utilized to inhibit biofilm growth and eradicate mature biofilms. 22–25 Moreover, silver nanoparticle-loaded nanocomposites, such as nanofibers and injectable hydrogels, have demonstrated effective control over biofilm growth and eradication of established biofilms. 25,26…”