Microbiological Profile, Antimicrobial Resistance, and Outcomes of Infections in Solid and Hematological Malignancies: A Systematic Review

Abstract

Background: Infectious complications are an important cause of morbidity, interruption of anticancer treatment, intensive care unit (ICU) admission, and mortality in patients with malignancies. The nature and severity of infection differ between solid and hematological cancers because of differences in disease biology, treatment intensity, duration of neutropenia, mucosal injury, invasive devices, and immune dysfunction. Objective: To systematically evaluate the clinicopathological characteristics, infectious complications, microbiological profiles, antimicrobial resistance patterns, treatment approaches, and clinical outcomes among patients with solid and hematological malignancies. Methods: This systematic review was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 framework. MEDLINE/PubMed, Embase, Scopus, and Web of Science were considered for literature identification, supplemented by citation searching. Adult studies reporting infectious complications, microbiological findings, antimicrobial resistance, treatment, ICU admission, sepsis, or mortality among patients with solid and/or hematological malignancies were eligible. Because of marked heterogeneity in study populations, infection definitions, resistance patterns, and outcome reporting, a narrative synthesis was undertaken. PRISMA screening dataset: 2,663 records were identified through bibliographic databases. Following removal of 846 duplicate records, 1,817 records underwent title and abstract screening. A total of 1,645 records were excluded, and 172 reports were sought for retrieval. Five reports could not be retrieved; therefore, 167 database-derived full-text reports were assessed for eligibility. Citation searching identified an additional 37 records, of which eight reports underwent full-text assessment. Overall, 175 full-text reports were evaluated. Following exclusion of 156 reports, 19 primary studies were retained for qualitative synthesis. No quantitative meta-analysis was performed because of substantial clinical and methodological heterogeneity. Results: The 19 included studies consistently demonstrated a substantial infectious burden among patients with malignancy. Hematological malignancies were particularly associated with profound neutropenia, recurrent febrile neutropenia, bloodstream infection, and opportunistic fungal infection, whereas solid tumors showed a greater contribution from anatomical obstruction, surgery, pulmonary infection, urinary infection, mucosal damage, and invasive devices. Gram-negative bacteria predominated in most contemporary cohorts, with Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter spp. among the most frequently identified pathogens. Multidrug resistance, ESBL production, and carbapenem resistance were frequently reported. Mortality ranged from approximately 10–25% in several bloodstream infection or febrile-neutropenia cohorts and exceeded 40–50% among patients with severe sepsis, septic shock, or critical illness. Septic shock, organ dysfunction, prolonged neutropenia, multidrug-resistant infection, inappropriate empirical antimicrobial treatment, pneumonia, and poor performance status were major predictors of mortality. Conclusion: Infections in cancer patients are heterogeneous and depend on the underlying malignancy, degree of treatment-induced immunosuppression, anatomical disruption, local microbial ecology, and severity of acute illness. Rapid microbiological evaluation, appropriate empirical antimicrobial therapy, risk-adapted prophylaxis, infection prevention, timely critical care, and antimicrobial stewardship are essential to improve outcomes.

Keywords: malignancy; solid tumor; hematological malignancy; febrile neutropenia; bloodstream infection; sepsis; antimicrobial resistance; multidrug resistance; treatment outcome; mortality