Staphylococcal Biofilm on the Surface of Catheters: Electron Microscopy Evaluation of the Inhibition of Biofilm Growth by RNAIII Inhibiting Peptide.

Adilson De Oliveira,Letícia Calixto Romero,Danilo Flávio Moraes Riboli,Katheryne Benini Martins,Luiza Pinheiro-Hubinger,Maria De Lourdes Ribeiro De Souza Da Cunha Cunha,Valéria Cataneli Pereira

doi:10.3390/antibiotics10070879

Adilson De Oliveira, Letícia Calixto Romero + Show 5 more

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https://doi.org/10.3390/antibiotics10070879

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Abstract

Staphylococcus aureus and coagulase-negative staphylococci (CoNS) have become the main causative agents of medical device-related infections due to their biofilm-forming capability, which protects them from the host’s immune system and from the action of antimicrobials. This study evaluated the ability of RNA III inhibiting peptide (RIP) to inhibit biofilm formation in 10 strains isolated from clinical materials, including one S. aureus strain, two S. epidermidis, two S. haemolyticus, two S. lugdunensis, and one isolate each of the following species: S. warneri, S. hominis, and S. saprophyticus. The isolates were selected from a total of 200 strains evaluated regarding phenotypic biofilm production and the presence and expression of the ica operon. The isolates were cultured in trypticase soy broth with 2% glucose in 96-well polystyrene plates containing catheter segments in the presence and absence of RIP. The catheter segments were observed by scanning electron microscopy. The results showed inhibition of biofilm formation in the presence of RIP in all CoNS isolates; however, RIP did not interfere with biofilm formation by S. aureus. RIP is a promising tool that might be used in the future for the prevention of biofilm-related infections caused by CoNS.

Highlights

Published: 20 July 2021Medical device-related infections are associated with the capability of bacteria to adhere and attach to surfaces and to subsequently form a biofilm [1,2]
Based on the above considerations, this study aimed to evaluate the effect of RNA III inhibiting peptide (RIP) on biofilm formation on catheters contaminated with S. aureus and coagulase-negative staphylococci (CoNS) by scanning electron microscopy (SEM) and the correlation with the expression of ica genes
The 150 CoNS isolates were identified as follows: 50 Staphylococcus epidermidis, 7 Staphylococcus lugdunensis, 20 each of Staphylococcus haemolyticus, Staphylococcus warneri, and Staphylococcus hominis blood culture isolates, and 20 Staphylococcus saprophyticus isolated from the urine of patients with urinary tract infection

Summary

Introduction

Medical device-related infections are associated with the capability of bacteria to adhere and attach to surfaces and to subsequently form a biofilm [1,2]. Biofilms are composed of communities of microorganisms enveloped by an extracellular matrix consisting of polysaccharides or proteins produced by the bacteria themselves, which remain adhered to abiotic or biotic surfaces [3,4]. The bacteria present inside the biofilm may have a different virulence and resistance phenotype in terms of gene transcription and growth rate [5]. Biofilm formation depends on the combination and expression of a variety of genes, whose expression is influenced by environmental factors such as growth conditions, carbohydrate supplementation, sub-inhibitory concentrations of antimicrobials, and high The composition of the biofilm matrix varies among staphylococcal strains; the main class of exopolysaccharides in staphylococcal biofilms is polysaccharide intercellular adhesin (PIA), which is synthesized by four proteins, IcaA, IcaD, IcaB, and IcaC, encoded by the icaADBC operon [7,8,9].

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