Carbapenem-resistant Organisms (CRO) include Carbapenem-resistant Enterobacteriaceae (CRE), Carbapenem-resistant Pseudomonas aeruginosa (CRPA) and Carbapenem-resistant Acinetobacter baumannii (CRAB). Due to the high fatality rate of CRO infection, and its potential for wide spread, it is currently one of the issues that seriously affect the global public health safety. In 2019, CDC of the United States listed CRE and CRAB as the highest level of "antibiotic-resistant bacteria with urgent threat", while CRPA was listed as "antibiotic-resistant bacteria with serious threat".

Previous studies show that in China, patients with hematological disease are at high-risk of CRE colonization and infection, but there still lack the data of colonization rate of CRPA and CRAB in patients with hematological disease. Intestinal flora is not only an important micro-ecological environment for the human body, but also an important place for the habitation of multidrug-resistant bacteria. The colonization of these bacteria can not only lead to the spread of bacteria in hospital, but also may lead to the translocation infection of carriers. Patients with hematological diseases are often in a state of neutropenia after chemotherapy. At the same time, chemotherapy drugs and various factors can cause intestinal mucosa damage, which is prone to induce intestinal microflora translocation, causing serious infections such as sepsis, and posing a serious threat to the prognosis of patients. Early detection of CRO carriers is not only beneficial to the control of nosocomial infection, but also beneficial to early precise anti-infection treatments, reducing the probability of infection and improving the prognosis of infected patients.

Our study is designed to clarify the intestinal carriage rate of carbapenem-resistant Organisms (CRO) in patients with hematological diseases, and the risk factors of intestinal CRO colonization in patients with hematological diseases and its correlation with subsequent infections. 5000 patients diagnosed with hematological diseases will be enrolled, and rectal swabs or feces will be collected to detect the CRE intestinal colonization. Subsequently, the last 6 months clinical data of CRO-colonized patients and matched non CRO-colonized patients (1:1) will be collected. Then, the randomly selected 200 CRO-colonized patients and matched 200 non CRO-colonized patients (1:1) are followed up for 12 months, a total of 400 patients will be enrolled. Every month, rectal swabs and relevant clinical data will be collected.

Inclusion Criteria:

• On a certain day in each chosed hospital, all the inpatients diagnosed with hematological malignancies diseases will be enrolled

Exclusion Criteria:

• Patients or their legal representatives refused to enter the study
• Patients died because of hematological malignancies diseases.

The study focused on the colonization rate of Carbapenem-resistant Organisms (CRO) in the intestine of Chinese patients with hematological malignancies diseases, who are at high-risk of CRE colonization and infection, but there still lack the data of colonization rate of CRPA and CRAB in patients with hematological disease.