title: Detection of methicillin-resistant Staphylococcus aureus directly by loop-mediated isothermal amplification and direct cefoxitin disk diffusion tests.
abstract: We evaluated the utility of 2 methods for detection of methicillin-resistant Staphylococcus aureus (MRSA) directly from signal-positive blood culture bottles: loop-mediated isothermal amplification (LAMP) assay, and direct cefoxitin disk diffusion (DCDD) test using a 30 μg cefoxitin disk. In parallel, standard microbiological identification and oxacillin susceptibility testing with MecA PCR was performed. Of 60 blood cultures positive for Gram-positive cocci in clusters, LAMP (via detection of the FemA and MecA genes) showed 100% sensitivity and specificity for identification of MRSA/MSSA. When coagulase-negative staphylococci were tested, sensitivity for detection of methicillin resistance was 91.7% and specificity was 100%. DCDD along with direct tube coagulase assay detected only 80.6% of MRSA/MSSA. LAMP showed higher diagnostic accuracy although DCDD was more cost-effective and did not require additional reagents or supplies.
authors: Department of Microbiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
authors: L
authors: L
authors: Metwally
authors: Department of Microbiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
authors: N
authors: N
authors: Gomaa
authors: Department of Clinical Pathology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
authors: R
authors: R
authors: Hassan
mesh_terms: D002440:Cefoxitin; D016172:DNA Fingerprinting / Q000379:methods; D052978:Disk Diffusion Antimicrobial Tests / Q000379:methods*; D006801:Humans; D016106:Methicillin Resistance / Q000187:drug effects / Q000235:genetics; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000097:blood / Q000382:microbiology*
chemical_list: D002440:Cefoxitin