Preliminary evaluation of adherence on abiotic and cellular surfaces of Acinetobacter baumannii strains isolated from catheter tips

Abstract

The cell surface hydrophobicity and adhesion to abiotic and cellular surfaces was tested in five clinical strains of Acinetobacter baumannii isolated from catheter tips. Biochemical and molecular characteristics of these strains were also studied. Hydrophobicity was characterized by a test for affinity to xylene. Adhesion to abiotic surfaces (polystyrene, formica, latex and glass) was evaluated in Petri plates using the stamp technique. Buccal epithelial cells were used for tests of adhesion to cellular surfaces. Adhesion to the catheter was evaluated by repeatedly rinsing the catheters and rolling them over nutrient agar. Molecular typing of the strains was done by the ERIC-PCR technique. The degree of hydrophobicity of the strains varied from hydrophobic to hydrophilic. All the strains adhered to the cell surfaces and to the catheters, and three of them strongly adhered to latex, polystyrene and formica. Catheter adhesion was reduced by meropenem. We found a direct relationship between the degree of bacterial hydrophobicity and adhesion to the abiotic surfaces, but not with adhesion to cellular surfaces, which suggests that different mechanisms are involved in adherence.

Biofilm formation by Acinetobacter baumannii isolated from medical devices at the intensive care unit of the University Hospital of Tlemcen (Algeria)

“…Accordingly, the hydrophobicity of the isolates was evaluated by determining the affinity of cells to hexadecane (Rosenberg, 1984). The results obtained from the MATH method revealed that the majority of A. baumannii strains isolated from a hydrophobic medical device surface showed a hydrophilic character which contradicts several studies which admitted that the hydrophobic cells tend to adhere to a hydrophobic substrate, while the hydrophilic cells tend to adhere to a hydrophilic substrate (Costa et al, 2006;Djeribi et al, 2013). It is suggested that there is a positive correlation between the degree of bacterial hydrophobicity and the adhesion to abiotic surfaces (Costa et al, 2006;Pour et al, 2011).…”

“…Cell surface hydrophobicity (CSH) of A. baumannii strains is also known to be associated with pathogenicity, bacterial adhesion and biofilm formation (Costa et al, 2006;Pour et al, 2011). Accordingly, the hydrophobicity of the isolates was evaluated by determining the affinity of cells to hexadecane (Rosenberg, 1984).…”

“…The ability of Acinetobacter strains to adhere to surfaces is an important mechanism in the pathogenicity of these bacteria. Although the adhesion ability is determined by specific factors, such as adhesins, and non-specific factors, such as hydrophobicity and cellular surface electrical discharge, it varies among strains (Costa et al, 2006). With regard to the role of A. baumannii in medical device-related infections, the purpose of this paper is to study for the first time in Algeria, the ability of clinical A. baumannii isolated from medical devices to form biofilm.…”

The Ecology, Biology and Pathogenesis of Acinetobacter spp.: An Overview

“…have been demonstrated to exhibit cell surface hydrophobicity, an important determinant bacterial adhesion. For a successful infection to occur, bacteria must successfully adhere to host cells (24). The hydrophobicity of a microorganism protects it from being phagocytosed and appears to play an important role in its attachment to various polymers.…”

“…For example, the urease activity of Acinetobacter promotes colonization of the mouse stomach (24). Urease also helps Acinetobacter spp.…”