Carbapenem-resistant Enterobacterales

The goal of this observational study is to characterize the clinical features of metallo-β-lactamase-producing carbapenem-resistant Enterobacterales (MBL-CRE) colonization and subsequent infection in patients after allogeneic hematopoietic stem cell transplantation (HSCT). The study aims to estimate the incidence of perianal MBL-CRE colonization, the proportion of subsequent infections, the associated risk factors, mortality, and the underlying antibiotic resistance mechanisms. The main questions this study seeks to answer are: 1. What is the incidence of perianal MBL-CRE colonization following allogeneic HSCT? 2. Among colonized patients, what proportion subsequently develop MBL-CRE infections? 3. What are the risk factors for colonization and infection, the patterns of antimicrobial resistance, and the mortality among infected patients? Participants will undergo perianal swab screening for CRE as part of their routine post-transplant care. MBL-CRE isolates identified from perianal swabs will undergo antimicrobial resistance genomic analysis to investigate bacterial transmission dynamics and resistance mechanisms.

In this study, we will evaluate the feasibility and clinical outcomes of risk adaptive empirical therapy to cover carbapenem resistance gram negative bacteria (CRO) in patients with hematological malignancies colonized with CRO. Patients assessed by the clinician as being at high risk for CRO infection and requiring intravenous antibiotics covering CRO must meet the following conditions: 1. Positive active screening for CRO or past CRO infection or local prevalence of CRO (e.g.,CRO detection rate\>20% among recently hospitalized patients); 2. Presence of fever or other possible signs and symptoms of infection; 3. Neutropenia(ANC\<0.1×10\^9/L)expected to last for ≥7 days,and having any of the following: * Gastrointestinal mucositis/peri-anal infection/intestinal obstruction; * Shock or severe sepsis; * Respiratory failure:deoxygenated PaO2\<60 mmHg or requiring mechanical ventilation; * Disseminated intravascular coagulation; * Altered mental status or psychiatric abnormalities; * Congestive heart failure requiring treatment; * Arrhythmia requiring treatment; * Recurrence of fever shortly after cessation of or during empirical treatment with carbapenems (≤7 days). The endpoints of study include incidence of blood-stream infection by CRO, incidence of all causes mortality, incidences of clinical and microbiology response.