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Nasal Screening for MRSA: Different Swabs – Different Results!

OBJECTIVES: Swab-based nasal screening is commonly used to identify asymptomatic carriage of Staphylococcus aureus in patients. Bacterial detection depends on the uptake and release capacities of the swabs and on the swabbing technique itself. This study investigates the performance of different swa...

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Autores principales: Warnke, Philipp, Frickmann, Hagen, Ottl, Peter, Podbielski, Andreas
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4213029/
https://www.ncbi.nlm.nih.gov/pubmed/25353631
http://dx.doi.org/10.1371/journal.pone.0111627
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author Warnke, Philipp
Frickmann, Hagen
Ottl, Peter
Podbielski, Andreas
author_facet Warnke, Philipp
Frickmann, Hagen
Ottl, Peter
Podbielski, Andreas
author_sort Warnke, Philipp
collection PubMed
description OBJECTIVES: Swab-based nasal screening is commonly used to identify asymptomatic carriage of Staphylococcus aureus in patients. Bacterial detection depends on the uptake and release capacities of the swabs and on the swabbing technique itself. This study investigates the performance of different swab-types in nasal MRSA-screening by utilizing a unique artificial nose model to provide realistic and standardized screening conditions. METHODS: An anatomically correct artificial nose model was inoculated with a numerically defined mixture of MRSA and Staphylococcus epidermidis bacteria at quantities of 4×10(2) and 8×10(2) colony forming units (CFU), respectively. Five swab-types were tested following a strict protocol. Bacterial recovery was measured for direct plating and after elution into Amies medium by standard viable count techniques. RESULTS: Mean recovered bacteria quantities varied between 209 and 0 CFU for MRSA, and 365 and 0 CFU for S. epidermidis, resulting swab-type-dependent MRSA-screening-sensitivities ranged between 0 and 100%. Swabs with nylon flocked tips or cellular foam tips performed significantly better compared to conventional rayon swabs referring to the recovered bacterial yield (p<0.001). Best results were obtained by using a flocked swab in combination with Amies preservation medium. Within the range of the utilized bacterial concentrations, recovery ratios for the particular swab-types were independent of the bacterial species. CONCLUSIONS: This study combines a realistic model of a human nose with standardized laboratory conditions to analyze swab-performance in MRSA-screening situations. Therefore, influences by inter-individual anatomical differences as well as diverse colonization densities in patients could be excluded. Recovery rates vary significantly between different swab-types. The choice of the swab has a great impact on the laboratory result. In fact, the swab-type contributes significantly to true positive or false negative detection of nasal MRSA carriage. These findings should be considered when screening a patient.
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spelling pubmed-42130292014-11-05 Nasal Screening for MRSA: Different Swabs – Different Results! Warnke, Philipp Frickmann, Hagen Ottl, Peter Podbielski, Andreas PLoS One Research Article OBJECTIVES: Swab-based nasal screening is commonly used to identify asymptomatic carriage of Staphylococcus aureus in patients. Bacterial detection depends on the uptake and release capacities of the swabs and on the swabbing technique itself. This study investigates the performance of different swab-types in nasal MRSA-screening by utilizing a unique artificial nose model to provide realistic and standardized screening conditions. METHODS: An anatomically correct artificial nose model was inoculated with a numerically defined mixture of MRSA and Staphylococcus epidermidis bacteria at quantities of 4×10(2) and 8×10(2) colony forming units (CFU), respectively. Five swab-types were tested following a strict protocol. Bacterial recovery was measured for direct plating and after elution into Amies medium by standard viable count techniques. RESULTS: Mean recovered bacteria quantities varied between 209 and 0 CFU for MRSA, and 365 and 0 CFU for S. epidermidis, resulting swab-type-dependent MRSA-screening-sensitivities ranged between 0 and 100%. Swabs with nylon flocked tips or cellular foam tips performed significantly better compared to conventional rayon swabs referring to the recovered bacterial yield (p<0.001). Best results were obtained by using a flocked swab in combination with Amies preservation medium. Within the range of the utilized bacterial concentrations, recovery ratios for the particular swab-types were independent of the bacterial species. CONCLUSIONS: This study combines a realistic model of a human nose with standardized laboratory conditions to analyze swab-performance in MRSA-screening situations. Therefore, influences by inter-individual anatomical differences as well as diverse colonization densities in patients could be excluded. Recovery rates vary significantly between different swab-types. The choice of the swab has a great impact on the laboratory result. In fact, the swab-type contributes significantly to true positive or false negative detection of nasal MRSA carriage. These findings should be considered when screening a patient. Public Library of Science 2014-10-29 /pmc/articles/PMC4213029/ /pubmed/25353631 http://dx.doi.org/10.1371/journal.pone.0111627 Text en © 2014 Warnke et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Warnke, Philipp
Frickmann, Hagen
Ottl, Peter
Podbielski, Andreas
Nasal Screening for MRSA: Different Swabs – Different Results!
title Nasal Screening for MRSA: Different Swabs – Different Results!
title_full Nasal Screening for MRSA: Different Swabs – Different Results!
title_fullStr Nasal Screening for MRSA: Different Swabs – Different Results!
title_full_unstemmed Nasal Screening for MRSA: Different Swabs – Different Results!
title_short Nasal Screening for MRSA: Different Swabs – Different Results!
title_sort nasal screening for mrsa: different swabs – different results!
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4213029/
https://www.ncbi.nlm.nih.gov/pubmed/25353631
http://dx.doi.org/10.1371/journal.pone.0111627
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