Abstract
Staphylococcus aureus is one of the most notorious pathogens and is frequently associated with nosocomial infections imposing serious risk to immune-compromised patients. This is in part due to its ability to colonize at the surface of indwelling medical devices and biofilm formation. Combating the biofilm formation with antibiotics has its own challenges like higher values of minimum inhibitory concentrations. Here, we describe a new approach to target biofilm formation by Gram positive bacteria. Sortase A is a transpeptidase enzyme which is responsible for tagging of around ∼22 cell surface proteins onto the outer surface. These proteins play a major role in the bacterial virulence. Sortase A recognizes its substrate through LPXTG motif. Here, we use this approach to install the synthetic peptide substrates onS. aureus. Sortase A substrate mimic, 6His-LPETG peptide was synthesized using solid phase peptide chemistry. Incorporation of the peptide on the cell surface was measured using ELISA. Effect of peptide incubation on Staphylococcus aureus biofilm was also studied. 71.1% biofilm inhibition was observed with 100 μM peptide while on silicon coated rubber latex catheter, 45.82% inhibition was observed. The present work demonstrates the inability of surface modified S. aureus to establish biofilm formation thereby presenting a novel method for attenuating its virulence.
Highlights
Most bacteria colonize on surfaces to form three-dimensional clusters called Biofilms
Trifluoroacetic acid (TFA), piperidine, thioanisole, 1,2Ethanediol, diethylether, N,N -dimethylformamide (DMF), Diisopropylethyl amine (DIPEA), rink amide resins, 1-Hydroxybenzotriazole (HOBt), and O-(benzotriazol-1-yl)N,N,N,N -tetramethyluronium hexafluorophosphate (HBTU) were obtained from Sigma Aldrich, N-α-Fmoc protected amino acids were obtained from Novabiochem (Merck, United States) and bacterial media was obtained from HimediaTM (India). 6X-Histidine and FLAG-LPETG peptide were purchased from Genscript Biotech (United States)
S. aureus is one of the key pathogens associated with hospital acquired infections involving medical devices including catheters, pacemakers, contact lenses, and dentures (Lewis, 2001; Piozzi et al, 2004)
Summary
Most bacteria colonize on surfaces to form three-dimensional clusters called Biofilms. Biofilm formation is one of the most important virulence mechanisms of many bacterial pathogens and considered to be the major cause of nosocomial infections especially in post-surgical and immune-compromised patients (Mirian et al, 2013; Zinaida et al, 2019). Staphylococcus aureus is the most common pathogen, which is involved in nosocomial infections and has been associated with significant mortality among hospitalized patients (Von-Eiff et al, 2001; Mulcahy and McLoughlin, 2016; Khatoon et al, 2018). The ability of S. aureus to form multilayered adherent biofilm to the surface of indwelling medical devices including catheters and medical implants, expressing series of toxins make them tolerant toward host defense mechanisms and common antibiotics (Neopane et al, 2018)
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