Ann Lab Med.  2012 May;32(3):206-209. 10.3343/alm.2012.32.3.206.

Contamination of X-ray Cassettes with Methicillin-resistant Staphylococcus aureus and Methicillin-resistant Staphylococcus haemolyticus in a Radiology Department

• Kim JS
• Kim HS
• Park JY
• Koo HS
• Choi CS
• Song W
• Cho HC
• Lee KM

• KMID: 1381686
• DOI: http://doi.org/10.3343/alm.2012.32.3.206

Abstract

BACKGROUND
We performed surveillance cultures of the surfaces of X-ray cassettes to assess contamination with methicillin-resistant Staphylococcus aureus (MRSA).
METHODS
The surfaces of 37 X-ray cassettes stored in a radiology department were cultured using mannitol salt agar containing 6 microg/mL oxacillin. Suspected methicillin-resistant staphylococcal colonies were isolated and identified by biochemical testing. Pulsed-field gel electrophoresis (PFGE) analysis was performed to determine the clonal relationships of the contaminants.
RESULTS
Six X-ray cassettes (16.2%) were contaminated with MRSA. During the isolation procedure, we also detected 19 X-ray cassettes (51.4%) contaminated with methicillin-resistant Staphylococcus haemolyticus (MRSH), identified as yellow colonies resembling MRSA on mannitol salt agar. PFGE analysis of the MRSA and MRSH isolates revealed that most isolates of each organism were identical or closely related to each other, suggesting a common source of contamination.
CONCLUSIONS
X-ray cassettes, which are commonly in direct contact with patients, were contaminated with MRSA and MRSH. In hospital environments, contaminated X-ray cassettes may serve as fomites for methicillin-resistant staphylococci.

Keyword

Staphylococcus aureus; Staphylococcus haemolyticus; MRSA; X-ray cassette; Contamination; Radiology; Infection control

MeSH Terms

Anti-Bacterial Agents/pharmacology
Diagnostic Equipment/*microbiology
Electrophoresis, Gel, Pulsed-Field
Humans
Methicillin Resistance
Methicillin-Resistant Staphylococcus aureus/drug effects/*isolation & purification
Microbial Sensitivity Tests
Oxacillin/pharmacology
Staphylococcus haemolyticus/drug effects/*isolation & purification

Figure

• 

  Fig. 1 Pulsed-field gel electrophoresis of SmaI macrorestriction fragments of methicillin-resistant Staphylococcus aureus isolates (N=6) contaminating the surfaces of X-ray cassettes. Two major pulsotypes are observed. Also shown are the corresponding specimen numbers. Marker, lambda concatamer.

• 

  Fig. 2 Pulsed-field gel electrophoresis of SmaI macrorestriction fragments of methicillin-resistant Staphylococcus haemolyticus isolates (N=19) contaminating the surfaces of X-ray cassettes. Two major pulsotypes are observed. Also shown are the corresponding specimen numbers. Marker, lambda concatamer.

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