Gut colonization with MDR gram negative organisms and its impact on bacteremia and sepsis development among children with hematological malignancies

Abstract Background: Gut colonization with multidrug-resistant organisms (MDROs) is a well-established risk factor for bloodstream infections (BSIs) in pediatric patients with hematological malignancies. This study aimed to prospectively assess the association between clinical and microbiological factors and the development of bloodstream or deep-seated infections among children colonized with MDROs. Methods: This prospective observational study was conducted at the National Cancer Institute – Cairo University. It included all pediatric patients (aged <18 years) with hematological malignancies presenting with febrile neutropenia, defined as a fever (≥38.0°C) and an absolute neutrophil count (ANC) <500 cells/mm³ or expected to decline below that threshold. Data were collected on day 0 and at discharge, encompassing demographics (age, gender), clinical features (malignancy type, early signs of septicemia, organ-specific infections), and microbiological profiles (CBC, CRP, liver/kidney function, blood cultures, antibiograms, and resistance profiles on days 0 and 1). Clinical outcomes were classified as complicated (e.g., sepsis, prolonged hospitalization, ICU admission) or uncomplicated. Results:A total of 200 patients were enrolled (mean age: 7.93 years). AML was the most frequent diagnosis, followed by ALL and BL. On admission, 60% of patients were colonized with MDROs. The most prevalent organisms were Escherichia coli (66%)—including carbapenem-resistant Enterobacteriaceae (CRE, 60%) and extended-spectrum beta-lactamase producers (ESBL, 40%)—Klebsiella CRE (16%), and MRSA (5%). Among colonized patients:41% developed a clinically documented infection (CDI),37% developed bacteremia, and33% experienced sepsis or septic shock. Over half of the colonized patients who developed CDI progressed to severe infection. Most infections occurred during the induction phase, likely due to intense immunosuppression. Statistical Findings:Colonization was significantly associated with bacteremia (p = 0.014);OR = 12.8 (Coefficient: +2.55), indicating colonized patients were 12.8 times more likely to develop bacteremia.CDI was a strong independent predictor of sepsis/shock (p < 0.001);OR = 11.4 (Coefficient: +2.44).Other factors—including age, gender, diagnosis type, and treatment phase—were not statistically significant predictors of these outcomes. Conclusion: MDRO colonization is highly prevalent in pediatric hematologic malignancy patients and significantly increases the risk of bacteremia and progression to severe infection. Clinically documented infection is a powerful predictor of sepsis/shock. These findings underscore the need for early detection, stringent infection control measures, and tailored antimicrobial strategies, especially during induction chemotherapy.