Utilizing Moist or Dry Swabs for the Sampling of Nasal MRSA Carriers? An In Vivo and In Vitro Study.
This study investigates the quantitative bacterial recovery of Methicillin-resistant Staphylococcus aureus (MRSA) in nasal screenings by utilizing dry or moistened swabs within an in vivo and an in vitro experimental setting. 135 nasal MRSA carriers were each swabbed in one nostril with a dry and in the other one with a moistened rayon swab. Quantitative bacterial recovery was measured by standard viable count techniques. Furthermore, an anatomically correct artificial nose model was inoculated with a numerically defined suspension of MRSA and swabbed with dry and moistened rayon, polyurethane-foam and nylon-flocked swabs to test these different settings and swab-materials under identical laboratory conditions. In vivo, quantities of MRSA per nostril in carriers varied between <101 and >107 colony forming units, with a median of 2.15x104 CFU. However, no statistically significant differences could be detected for the recovery of MRSA quantities when swabbing nasal carriers with moist or dry rayon swabs. In vitro testing confirmed the in vivo data for swabs with rayon, polyurethane and nylon-flocked tips, since pre-moistening of swabs did not significantly affect the quantities of retrieved bacteria. Therefore, pre-moistening of swabs prior to nasal MRSA sampling provides no advantage in terms of recovering greater bacterial quantities and therefore can be omitted. In addition, this situation can be mimicked in an in vitro model, thereby providing a useful basis for future in vitro testings of new swab types or target organisms for screening approaches.
Institute of Medical Microbiology, Virology, and Hygiene, University Medicine Rostock, Rostock, Germany.
Philipp
P
Warnke
Institute of Medical Microbiology, Virology, and Hygiene, University Medicine Rostock, Rostock, Germany.
Annette
A
Devide
Institute of Medical Microbiology, Virology, and Hygiene, University Medicine Rostock, Rostock, Germany.
Mirjam
M
Weise
Institute of Medical Microbiology, Virology, and Hygiene, University Medicine Rostock, Rostock, Germany.|Department of Tropical Medicine at the Bernhard Nocht Institute, German Armed Forces Hospital of Hamburg, Hamburg, Germany.
Hagen
H
Frickmann
Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Norbert Georg
NG
Schwarz
Department of Internal Medicine, Division of Gastroenterology and Endocrinology, University Medicine Rostock, Rostock, Germany.
Holger
H
Schäffler
Department of Prosthodontics and Material Sciences, University Medicine Rostock, Rostock, Germany.
Peter
P
Ottl
Institute of Medical Microbiology, Virology, and Hygiene, University Medicine Rostock, Rostock, Germany.
Andreas
A
Podbielski
D001431:Bacteriological Techniques / Q000295:instrumentation / Q000379:methods; D002353:Carrier State / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus; D008953:Models, Anatomic; D009296:Nasal Cavity / Q000382:microbiology*; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000382:microbiology