OBJECTIVES: To evaluate the performance of a cefoxitin 30 microg disc on Iso-Sensitest agar, using a semi-confluent inoculum and overnight incubation at 35-36 degrees C, for detection of methicillin-resistant Staphylococcus aureus (MRSA). METHODS: A total of 457 S. aureus, including 190 MRSA of several defined PFGE types and a number of low-level resistant isolates, were tested with a cefoxitin 30 microg disc on Iso-Sensitest agar, using a semi-confluent inoculum and overnight incubation at 35-36 degrees C. This method was compared with the standard SRGA (Swedish Reference Group for Antibiotics) method (oxacillin 1 microg disc on Iso-Sensitest agar supplemented with 5% defibrinated horse blood, confluent growth and 24 h incubation in ambient air at 30 degrees C). RESULTS: The cefoxitin method was excellent, with a sensitivity of 100% and a specificity of 99% using an interpretative zone diameter of S > or = 29 mm and R < 29 mm. Its performance was much better than the SRGA method, which with this collection of difficult strains had a sensitivity of only 78% using the current breakpoint of S > or = 12 mm. CONCLUSION: We suggest that the cefoxitin method should replace that currently recommended by the SRGA for the detection of MRSA, and that it would fit well into BSAC methodology.
OBJECTIVES: To evaluate the performance of a cefoxitin 30 microg disc on Iso-Sensitest agar, using a semi-confluent inoculum and overnight incubation at 35-36 degrees C, for detection of methicillin-resistant Staphylococcus aureus (MRSA). METHODS: A total of 457 S. aureus, including 190 MRSA of several defined PFGE types and a number of low-level resistant isolates, were tested with a cefoxitin 30 microg disc on Iso-Sensitest agar, using a semi-confluent inoculum and overnight incubation at 35-36 degrees C. This method was compared with the standard SRGA (Swedish Reference Group for Antibiotics) method (oxacillin 1 microg disc on Iso-Sensitest agar supplemented with 5% defibrinated horse blood, confluent growth and 24 h incubation in ambient air at 30 degrees C). RESULTS: The cefoxitin method was excellent, with a sensitivity of 100% and a specificity of 99% using an interpretative zone diameter of S > or = 29 mm and R < 29 mm. Its performance was much better than the SRGA method, which with this collection of difficult strains had a sensitivity of only 78% using the current breakpoint of S > or = 12 mm. CONCLUSION: We suggest that the cefoxitin method should replace that currently recommended by the SRGA for the detection of MRSA, and that it would fit well into BSAC methodology.
Authors: M F Q Kluytmans-van den Bergh; M C Vos; B M W Diederen; C M J E Vandenbroucke-Grauls; A Voss; J A J W Kluytmans Journal: Eur J Clin Microbiol Infect Dis Date: 2013-07-27 Impact factor: 3.267
Authors: R Skov; R Smyth; A R Larsen; A Bolmstrôm; A Karlsson; K Mills; N Frimodt-Moller; G Kahlmeter Journal: J Clin Microbiol Date: 2006-10-18 Impact factor: 5.948
Authors: P Bemer; M E Juvin; G Le Gargasson; H Drugeon; A Reynaud; S Corvec Journal: Eur J Clin Microbiol Infect Dis Date: 2010-04-06 Impact factor: 3.267
Authors: John D Perry; Amie Davies; Lynne A Butterworth; Andrew L J Hopley; Audrey Nicholson; F Kate Gould Journal: J Clin Microbiol Date: 2004-10 Impact factor: 5.948