Patients with haematological malignancies (HM patients) are at high risk of infections [1] because of neutropenia, mucosal barrier loss and high-dose chemotherapy [2]. Bloodstream infections (BSI) are a common occurrence in HM patients, with a prevalence of 11–38% [3]. Multidrug-resistant Gram-negative bacteria (MDR-GNB), such as carbapenem-resistant Enterobacterales (CRE) and extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, are frequently identified as the aetiological pathogens. The mortality rate of HM patients with BSI approaches 40% [4], and that of HM patients with CRE infection ranges from 45.6% to 100% [5].

Intestinal MDR-GNB colonisation in HM patients has been identified as a risk factor for subsequent infections [2]. Following rectal MDR-GNB colonisation, over 30% of haematopoietic stem cell transplant (HSCT) patients acquired subsequent infections caused by the same species as the colonised pathogen [6]. The gut flora is thought to be the primary reservoir for MDR-GNB; therefore, active screening for intestinal MDR-GNB colonisation has become a crucial infection control strategy, which is strongly recommended in HM treatment guidelines and is frequently used in healthcare settings [5,7,8].

Prevalence of and risk factors for intestinal colonisation by MDR-GNB in HM patients have been evaluated in recent years; however, there has been no systematic review and meta-analysis conducted on MDR-GNB intestinal colonisation exclusively for HM patients. Therefore, a systematic review and meta-analysis was conducted to explore the pooled prevalence of and risk factors for intestinal colonisation with MDR-GNB (CRE and ESBL) in HM patients, with the aim to help control colonisation and subsequent infections to provide better management of this vulnerable patient population.