Definition
All definitions were defined according to criteria established by the Centers for Disease Control and Prevention. The most common types of NI are hospital-acquired pneumonia (HAP), ventilator-associated pneumonia (VAP), blood stream infection (BSI), catheter-related blood stream infection (CRBSI), catheter-associated urinary tract infection (CAUTI) and surgical site infection (SSI) [6-8]. VAP is a subset of HAP which occurs over 48 hours after endotracheal intubation. In our study, both HAP and VAP were included into the type of pneumonia. CRBSI is a subset of BSI with the presence of central venous catheters and signs of catheter insertion site infection. SSI can be divided into three types: superficial SSI, deep SSI and mediastinitis.
Antibiotics resistance means acquired resistance except for natural resistance. Multidrug-resistant (MDR) bacteria means the one that were antimicrobial resistant to three or more classes of antibiotics. And bacteria only sensitive to colistin and/or tigecycline was defined as extensively drug resistant (XDR) bacteria [9].