Evaluation of colonisation of pacemakers and defibrillators from strains that produce biofilm and their study with atomic force microscopy

Abstract number: P1845

Arampatzi S., Giannoglou G., Protonotariou E., Logothetidis S., Paraskevaidis S., Vasilikos V., Styliadis I., Diza E.

Objectives: Part of the pathogenesis of infections in patients with cardiac implants is the ability of microorganisms to create biofilms, which are resistant to the immune responses and antimicrobial agents. Recently, Atomic Force Microscopy (AFM) is being used for studing phenomena such as the irreversible cell adhesion and biofilm formation. The aim of this study was the investigation of colonization of implantable cardiac pacemakers and defibrillators in hospitalised patients, the detection of possible biofilm creation by these strains, and their study with AFM.

Methods: The study included 26 patients that were hospitalized in Cardiologic Clinic from which, 25 brought pacemaker and one defibrillator. Reason for admission was replacement of the pacemaker system. Tissue specimen from the fibrous capsule surrounding the pacemaker and swab from coating of fibrous capsule was obtained from each patient. Specimens were cultured following routine methods. Bacterial identification and antimicrobial susceptibility was performed with VITEK2-automated system (bioMerieux, France). The Tube method was used for the detection of slime-producing ability and in vitro biofilm formation was quantified by the polystyrene adherence assay. All isolates with high and moderate slime production were studied with AFM tapping mode technique on a surface of Highly Oriented Pyrolytic Graphite (HOPG). The surface roughness was estimaded by the measurement of root-mean-square roughness (Rrms) and peak-to-peak distance (P2P) parameters.

Results: (1) Pacemakers and defibrillators showed high rates of colonization (74%), mainly by Staphylococcus hominis and Staphylococcus epidermidis. (2) 50% of the strains isolated (mainly S. hominis, S. epidermidis) were positive for slime production with the tube method, while the quantitative method showed that 15% of the strains were high-slime producers (S. hominis, Rhizobium radiobacter) and 7% were moderate producers (S. hominis, Leuconostoc spp). (3) The study of surface roughness on HOPG with AFM showed that high and moderate slime producers presented different roughness (Rrms and P2P) compared with slime non producers.

Conclusions: (1) Implantable cardiac pacemaker systems are highly colonized by strains of normal skin microflora 50% of which may produce slime. (2) AFM is a powerful technique that can be used for studying the matrix of microorganisms that create biofilm.

Session Details

Date: 07/05/2011
Time: 00:00-00:00
Session name: Abstracts of 21st ECCMID / 27th ICC
Location: Milan, Italy, 7 - 10 May 2011
Presentation type:
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