Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising

<p>Abstract</p> <p>Background</p> <p>Post-sternotomy mediastinitis (PSM) is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. <it>Staphylococcus aureus </it>is one of the most commonly encountered bacterial pathogen...

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Main Authors: Kose Necmi, Bayindir Ismet, Tamer Lulufer, Sucu Nehir, Aytacoglu Barlas, Ersoz Gulden, Kaya Ali, Dikmengil Murat
Format: Article
Language:English
Published: BMC 2006-04-01
Series:BMC Infectious Diseases
Online Access:http://www.biomedcentral.com/1471-2334/6/76
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spelling doaj-213471866a85473cab462b4d832a833a2020-11-25T03:40:04ZengBMCBMC Infectious Diseases1471-23342006-04-01617610.1186/1471-2334-6-76Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promisingKose NecmiBayindir IsmetTamer LuluferSucu NehirAytacoglu BarlasErsoz GuldenKaya AliDikmengil Murat<p>Abstract</p> <p>Background</p> <p>Post-sternotomy mediastinitis (PSM) is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. <it>Staphylococcus aureus </it>is one of the most commonly encountered bacterial pathogen cultured from mediastinal samples obtained from patients with PSM. A component of the membrane of the gram positive bacteria, lipoteichoic acid, stimulates the blood monocytes and macrophages to secrete cytokines, radicals and nitrogen species leading to oxido-inflammatory damage. This seems to be responsible for the high mortality rate in PSM. For the evaluation of the pathogenesis of infection or for the investigation of alternative treatment models in infection, no standard model of mediastinitis seems to be available. In this study, we evaluated four mediastinitis models in rats.</p> <p>Methods</p> <p>The rats were divided into four groups to form different infection models. Group A: A suspension of 1 × 10<sup>7 </sup>colony-forming units <it>Staphylococcus aureus </it>in 0,5 mL was inoculated from the right second intercostal space into the mediastinum. Group B: A hole was created in the right second intercostal space and a piece of stainless-steel implant with a length of 0.5 cm was inserted into the mediastinum and a suspension of 1 × 10<sup>7 </sup>cfu bacteria in 0,5 mL was administered via the tail vein. Group C: Precolonized stainless-steel implant was inserted into the mediastinum. Group D: Precolonized stainless-steel implant was inserted into the mediastinum and the bacteria suspension was also injected into the mediastinum. On the 10<sup>th </sup>day, rats were sacrificed and the extension of infection in the mediastenae was evaluated by quantitative cultures. Myeloperoxidase activity (MPO) and malondialdehyde (MDA) levels were determined in the sera to evaluate the neutrophil activation and assess the inflammatory oxidation.</p> <p>Results</p> <p>The degree of infection in group C and D were 83.3% and 100% respectively (<it>P </it>< 0.001). MDA levels were significantly higher in these two groups than the others (<it>P </it>< 0.001).</p> <p>Conclusion</p> <p>Infected implants and high bacterial concentration administration were the two important components that played a significant role in the outcome of a successful infection in mediastinum in a rat model.</p> http://www.biomedcentral.com/1471-2334/6/76
collection DOAJ
language English
format Article
sources DOAJ
author Kose Necmi
Bayindir Ismet
Tamer Lulufer
Sucu Nehir
Aytacoglu Barlas
Ersoz Gulden
Kaya Ali
Dikmengil Murat
spellingShingle Kose Necmi
Bayindir Ismet
Tamer Lulufer
Sucu Nehir
Aytacoglu Barlas
Ersoz Gulden
Kaya Ali
Dikmengil Murat
Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising
BMC Infectious Diseases
author_facet Kose Necmi
Bayindir Ismet
Tamer Lulufer
Sucu Nehir
Aytacoglu Barlas
Ersoz Gulden
Kaya Ali
Dikmengil Murat
author_sort Kose Necmi
title Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising
title_short Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising
title_full Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising
title_fullStr Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising
title_full_unstemmed Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising
title_sort comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising
publisher BMC
series BMC Infectious Diseases
issn 1471-2334
publishDate 2006-04-01
description <p>Abstract</p> <p>Background</p> <p>Post-sternotomy mediastinitis (PSM) is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. <it>Staphylococcus aureus </it>is one of the most commonly encountered bacterial pathogen cultured from mediastinal samples obtained from patients with PSM. A component of the membrane of the gram positive bacteria, lipoteichoic acid, stimulates the blood monocytes and macrophages to secrete cytokines, radicals and nitrogen species leading to oxido-inflammatory damage. This seems to be responsible for the high mortality rate in PSM. For the evaluation of the pathogenesis of infection or for the investigation of alternative treatment models in infection, no standard model of mediastinitis seems to be available. In this study, we evaluated four mediastinitis models in rats.</p> <p>Methods</p> <p>The rats were divided into four groups to form different infection models. Group A: A suspension of 1 × 10<sup>7 </sup>colony-forming units <it>Staphylococcus aureus </it>in 0,5 mL was inoculated from the right second intercostal space into the mediastinum. Group B: A hole was created in the right second intercostal space and a piece of stainless-steel implant with a length of 0.5 cm was inserted into the mediastinum and a suspension of 1 × 10<sup>7 </sup>cfu bacteria in 0,5 mL was administered via the tail vein. Group C: Precolonized stainless-steel implant was inserted into the mediastinum. Group D: Precolonized stainless-steel implant was inserted into the mediastinum and the bacteria suspension was also injected into the mediastinum. On the 10<sup>th </sup>day, rats were sacrificed and the extension of infection in the mediastenae was evaluated by quantitative cultures. Myeloperoxidase activity (MPO) and malondialdehyde (MDA) levels were determined in the sera to evaluate the neutrophil activation and assess the inflammatory oxidation.</p> <p>Results</p> <p>The degree of infection in group C and D were 83.3% and 100% respectively (<it>P </it>< 0.001). MDA levels were significantly higher in these two groups than the others (<it>P </it>< 0.001).</p> <p>Conclusion</p> <p>Infected implants and high bacterial concentration administration were the two important components that played a significant role in the outcome of a successful infection in mediastinum in a rat model.</p>
url http://www.biomedcentral.com/1471-2334/6/76
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