Canine scent detection as a tool to distinguish meticillin-resistant Staphylococcus aureus (original) (raw)

Letters to the Editor Canine scent detection as a tool to distinguish meticillin-resistant Staphylococcus aureus Sir, Meticillin-resistant Staphylococcus aureus (MRSA) is a frequently reported hospital-and community-acquired pathogen. New fast and inexpensive detection tools are needed for detection. Current molecular assays are based on detection of Staphylococcal Cassette Chromosome mec (SCCmec), which contains the mecA gene [1]. Secondgeneration polymerase chain reaction assays are single-locus assays targeting the open reading frame X (orfX)eSCCmec junction, and continue to have specificity issues related to strains which have lost the mecA gene but retained the SCCmec cassette junction (SCCmec remnant strains, MSSAr) [1,2]. Canine scent detection is a rapidly expanding field of study in medicine [3e5]. Studies have shown that meticillin-resistant and-susceptible (MSSA) S. aureus may be differentiated based solely on their volatile organic compound (VOC) profiles [6,7]. We hypothesized that canine scent detection could be used as a diagnostic tool for the detection of MRSA. Our objective was to determine whether dogs could distinguish MRSA from the similar strains: MSSA, mecA-positive Staphylococcus epidermidis (MRSE), and MSSAr, using bacterial cultures. The study was approved by both the North York General Hospital Research Ethics Board and the Centre for Phenogenomics Animal Care Committee. The MRSA type strains Canadian (C)MRSA-2 (SCCmec type II, USA100) and Canadian MRSA-10 (SCCmec type IV, USA300) were obtained from the National Microbiology Laboratory (Winnipeg, Canada). Other strains used were S. aureus ATCC Ò 25923Ô (MSSA), a clinical isolate of MRSE, and SCCmec (Type I) remnant MSSA (MSSAr) [8]. Isolates were inoculated on to fresh 5% sheep blood agar plates (BAP) in a set pattern (Supplementary