Methicillin-sensitive and resistant Staphylococcus aureus (MSSA and MRSA, respectively) can cause\nnon-tuberculosis infectious spondylitis. In 43 cases of bacterial infectious spondylitis, Mycobacterium\ntuberculosis and S. aureus were the two major causative pathogens. MRSA caused more anterior\noperations and thoracic infections, while MSSA caused more posterior infections and lumbar\ninfections. Differences between six S. aureus isolates from infectious spondylitis were characterized.\nMLST and staphylococcal cassette chromosome mec (SCCmec) analysis identified MSSA\nST959 and ST30 isolates, MRSA ST239/SCCmec IIIA isolates 2 and 3, ST59/SCCmec IIIA-like isolate\n6, and ST30/SCCmec IV isolate 5. While all of the isolates were resistant to penicillin and ampicillin,\nthe MRSA isolates were more resistant than the MSSA isolates. Carbapenem-resistant MRSA\nST239/SCCmec IIIA and ST59/SCCmec IIIA-like isolates of the agr1 type were also resistant to\nclindamycin and erythromycin. Leukocidin genes (pvl or lukED) and hemolysin genes (hla, hld and\nhlg) were present in all of the isolates. All six isolates caused more necrosis than apoptosis in the\nhuman alveolar basal epithelial cell line A549; however, ST59/SCCmec IIIA-like isolate 6, ST30/ SCCmec IV isolate 5 with pvl genes, and MSSA ST30 isolates with tst caused greater than 40% cell\ndeath after the 4-h incubation. Regardless of the MRSA isolate and its SCCmec type or the MSSA\nisolate, the infectious spondylitis-associated S. aureus isolates differed genetically, and the pvl and\ntst genes may be important genes for cell necrosis.
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