Maldi tof ms version 3.2

During the study period, 124 MRSA isolates collected consecutively from patients with SSTIs were studied. Only the first isolate per patient was considered. SSTIs included cellulitis, erysipelas, impetigo, folliculitis, furuncles, abscesses and carbuncles. The swabs, needle aspirates and tissue biopsies taken from the patients were promptly transported to the laboratory for microbiological analyses, including Gram stain and culture.
Specimens were cultured onto Columbia blood, chocolate, Drigalski, Achaedler and Sabouraud dextrose agar, and incubated at 36 °C (BioMérieux, Marcy L‘Etoile, France). Isolates were identified on the basis of colony morphology, Gram stain, catalase test, coagulase test and the use of the matrix-assisted laser desorption time of flight mass spectrometry (MALDI-TOF MS) (Version 3.2) (BioMerieux).

Blood was collected in blood culture bottles that were promptly transported to the microbiology laboratory for further processing. Bottles were loaded and incubated on the BacT/Alert Virtuo system (BioMérieux, Marcy L’Étoile, France) for five days unless growth was detected earlier. When a culture bottle had been signaled positive, gram stain and subcultures were immediately performed. For the isolation of bacterial pathogens, specimens were inoculated onto Columbia blood, chocolate, MaC Conkey, and Schaedler blood agar (all products of bioMérieux SA, Marcy L’Étoile, France) and incubated at 36 °C. Identification of bacterial species was performed by standard biochemical assays and the Vitek 2 automated system and confirmed by the matrix-assisted laser desorption time of flight, mass spectrometry (MALDI-TOF MS) (version 3.2) (both products of bioMérieux SA). The Vitek 2 automated system was also used for antimicrobial susceptibility testing and results were interpreted according to the Clinical and Laboratory Standards Institute (CLSI) criteria [27 ].

Blood cultures were obtained from patients to investigate the possibility of bacteremia. Blood was collected in blood culture bottles that were promptly transported to the microbiology laboratory for further processing. Bottles were loaded and incubated on the BacT/Alert Virtuo system (BioMérieux, Marcy L’ Etoile, France) for five days unless growth was detected earlier. When a culture bottle signaled positive, gram stain and subcultures were then immediately performed. For the isolation of bacterial pathogens, specimens were inoculated onto Columbia blood, chocolate, MaC Conkey, and Schaedler blood agar (all products of bioMérieux SA, Marcy L’Étoile, France) and incubated at 36 °C. Identification of bacterial species was performed by standard biochemical assays and the Vitek 2 automated system and confirmed by the matrix-assisted laser desorption time of flight mass spectrometry (MALDI-TOF MS) (version 3.2) (both products of bioMérieux SA, Marcy L’Étoile, France). The Vitek 2 automated system was also used for antibiotic susceptibility testing and results were interpreted according to the 2021 Clinical and Laboratory Standards Institute (CLSI) criteria [22 ]. As quality control strains, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, S. aureus ATCC 25923, and E. faecalis ATCC 29212 were used.