Vitek 2 compact system analysis

Microbiological culture was performed by semi-quantitative or quantitative methods. The proximal tip of the extracted catheter (about 5 cm long) was rolled several times over a Columbia blood agar plate medium (Difco, Franklin Lakes, NJ, USA) in a ‘Z’ pattern, and following incubation, microbial growths were identified by standard microbiological procedures. A panel of culture agar media (blood, chocolate, etc) was used for the semi-quantitation of microbial loads in clinical samples. All media were incubated for 18–24 h in atmospheres appropriate for the species sought. Isolates were identified to species level and antimicrobial susceptibility determined using the VITEK-2 compact system analysis (BioMerieux, Saint-Vulbas, France), with reference to the Clinical and Laboratory Standards Institute for MIC breakpoint determination. Breakpoint concentrations of cefoxitin of ≤4 and ≥ 8 mg/L were used to differentiate between methicillin-susceptible and methicillin-resistant Staphylococcus aureus isolates. Multiple drug-resistant (MDR) and extensively drug-resistant (XDR) strains were defined as previously described [16 (link)]. Carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and carbapenem-resistant Klebsiella pneumoniae (CRKP) were defined by resistance to imipenem or meropenem.