The Antibiofilm Effect of a Medical Device Containing TIAB on Microorganisms Associated with Surgical Site Infection.

Valentina Puca,Gabriella Mincione,Rossella Grande,Raffaella Muraro,Simone Carradori,Simone Guarnieri,Francesca Sisto,Nicola Macchione,Tonino Traini

doi:10.3390/molecules24122280

Abstract

Surgical site infections (SSIs) represent the most common nosocomial infections, and surgical sutures are optimal surfaces for bacterial adhesion and biofilm formation. Staphylococcus spp., Enterococcus spp., and Escherichia coli are the most commonly isolated microorganisms. The aim of this research was to evaluate the antibiofilm activity of a medical device (MD) containing TIAB, which is a silver-nanotech patented product. The antibacterial effect was evaluated against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, and E. coli ATCC 25922 by assessing the minimum inhibitory concentration (MIC) by the Alamar Blue® (AB) assay. The antibiofilm effect was determined by evaluation of the minimum biofilm inhibitory concentration (MBIC) and colony-forming unit (CFU) count. Subsequently, the MD was applied on sutures exposed to the bacterial species. The antimicrobial and antibiofilm effects were evaluated by the agar diffusion test method, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM). The MIC was determined for S. aureus and E. faecalis at 2 mg/mL, while the MBIC was 1.5 mg/mL for S. aureus and 1 mg/mL for E. faecalis. The formation of an inhibition zone around three different treated sutures confirmed the antimicrobial activity, while the SEM and CLSM analysis performed on the MD-treated sutures underlined the presence of a few adhesive cells, which were for the most part dead. The MD showed antimicrobial and antibiofilm activities versus S. aureus and E. faecalis, but a lower efficacy against E. coli. Surgical sutures coated with the MD have the potential to reduce SSIs as well as the risk of biofilm formation post-surgery.

Highlights

Surgical site infections (SSIs) are classified as ”infections occurring within 30 days after a surgical operation and affecting either the incision or deep tissue at the operation site” [1,2]
A biofilm is a microbial community protected by a self-produced complex matrix of extracellular polymeric substances (EPS) adherent to each other and/or to a surface that protects the microorganisms from the attack by the antimicrobials and the host immune system [5,6]
The antimicrobial and antibiofilm effects of the medical device (MD) were evaluated against three reference strains: S. aureus ATCC 29213, E. faecalis 29212, and E. coli 25922 (Table 1)

Summary

Introduction

Surgical site infections (SSIs) are classified as ”infections occurring within 30 days after a surgical operation (or within one year if an implant is left in place after the procedure) and affecting either the incision or deep tissue at the operation site” [1,2]. SSIs represent the most common nosocomial infections and account for 14–16% of all healthcare-associated infections among hospitalized patients and 38% among surgical patients [2,3]. SSIs are the cause of morbidity and in some cases mortality [4], and increase healthcare costs, since they imply a prolonged hospitalization, additional diagnostic tests, massive antibiotics use, and sometimes invasive surgery. Surgical sutures represent a suitable substrate for microbial adhesion and, for biofilm formation. A significant rate of hospital-acquired infections is associated with biofilms developed by pathogens and/or opportunistic pathogens. A biofilm is a microbial community protected by a self-produced complex matrix of extracellular polymeric substances (EPS) adherent to each other and/or to a surface that protects the microorganisms from the attack by the antimicrobials and the host immune system [5,6]

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