Vancomycin-resistant enterococci in acute myeloid leukemia and myelodysplastic syndrome patients undergoing induction chemotherapy with idarubicin and cytarabine

Infectious complications of induction treatment for acute myeloid leukaemia using the "7 + 3" protocol without antibiotic prophylaxis - 15 years of experience of one clinical site

BACKGROUND

Infectious complications during induction chemotherapy of acute myeloid leukaemia are very common. Prophylactic use of antibiotics however is an ongoing challenge in this situation due to bacterial multi-drug resistance. The aim of this study was to provide a comprehensive overview of the incidence of infectious complications in patients with AML undergoing induction therapy using the "7+3" protocol without routine antibiotic prophylaxis at one clinical site providing specialised haematological care in the Czech Republic, over a period of 15 years. The study also evaluates the aetiological spectrum of causative agents and the development of antibiotic resistance in the context of the use of the various classes of antibiotics. The analysis includes evaluation of the importance of risk factors for infectious complications and their impact on treatment of the underlying disease. The data are compared with published figures for similar cohorts of patients.

PATIENTS AND METHODS

This study presents a retrospective analysis of infectious complications in 242 patients with acute myeloid leukaemia undergoing the first cycle of induction therapy without routine antibiotic prophylaxis in one clinical site in Czech Republic during years 2006-2020.

RESULTS

A total of 363 febrile episodes (FE) were recorded. At least 1 FE during the induction was detected in 229 (94.6%) patients. Clinically defined infection was the cause in 96 (26.4%) FEs and blood stream infection in 69 (19.0%) FEs. Both complications occurred simultaneously in 29 (8.0%) FEs. 169 (46.6%) FEs were evaluated as fever of unknown origin (FUO). The achievement of complete remission had a significant effect on the duration of the FE (6 vs. 9 days, P=0.0005) and on the overall survival duration (79.3 vs. 6.5 months, P<0.0001). Patients diagnosed with infection or FUO at diagnosis were significantly more likely to suffer from colonisation by multi-drug resistant bacterial strains at discharge (29.2% vs. 16.3%, P=0.022). This group of patients used antibiotic therapy for a significantly longer time (35 vs. 23 days, P<0.0001). Infection was a contributing cause of death in 18 (7.4%) patients. Mortality was significantly related to the failure to achieve complete remission (P<0.0001).

CONCLUSION

Infectious mortality during induction treatment without routine antibiotic prophylaxis was comparable to the published cohorts with prophylaxis. Regular microbiology surveillance with adequate initial antibiotic treatment can compensate routine antibiotic prophylaxis with slower development of antibiotic resistance.

Clinical outcomes of antimicrobial resistance in cancer patients: a systematic review of multivariable models

BACKGROUND

Infections are major causes of disease in cancer patients and pose a major obstacle to the success of cancer care. The global rise of antimicrobial resistance threatens to make these obstacles even greater and hinder continuing progress in cancer care. To prevent and handle such infections, better models of clinical outcomes building on current knowledge are needed. This internally funded systematic review (PROSPERO registration: CRD42021282769) aimed to review multivariable models of resistant infections/colonisations and corresponding mortality, what risk factors have been investigated, and with what methodological approaches.

METHODS

We employed two broad searches of antimicrobial resistance in cancer patients, using terms associated with antimicrobial resistance, in MEDLINE and Embase through Ovid, in addition to Cinahl through EBSCOhost and Web of Science Core Collection. Primary, observational studies in English from January 2015 to November 2021 on human cancer patients that explicitly modelled infection/colonisation or mortality associated with antimicrobial resistance in a multivariable model were included. We extracted data on the study populations and their malignancies, risk factors, microbial aetiology, and methods for variable selection, and assessed the risk of bias using the NHLBI Study Quality Assessment Tools.

RESULTS

Two searches yielded a total of 27,151 unique records, of which 144 studies were included after screening and reading. Of the outcomes studied, mortality was the most common (68/144, 47%). Forty-five per cent (65/144) of the studies focused on haemato-oncological patients, and 27% (39/144) studied several bacteria or fungi. Studies included a median of 200 patients and 46 events. One-hundred-and-three (72%) studies used a p-value-based variable selection. Studies included a median of seven variables in the final (and largest) model, which yielded a median of 7 events per variable. An in-depth example of vancomycin-resistant enterococci was reported.

CONCLUSIONS

We found the current research to be heterogeneous in the approaches to studying this topic. Methodological choices resulting in very diverse models made it difficult or even impossible to draw statistical inferences and summarise what risk factors were of clinical relevance. The development and adherence to more standardised protocols that build on existing literature are urgent.

Antimicrobial therapy during cancer treatment: Beyond antibacterial effects

Cancer treatment options have evolved to include immunotherapy and targeted therapy, in addition to traditional chemoradiation. Chemoradiation places the patient at a higher risk of infection through a myelosuppressive effect. High clinical suspicion and early use of antimicrobials play a major role in decreasing any associated morbidity and mortality. This has led to a widespread use of antimicrobials in cancer patients. Antimicrobial use, however, does not come without its perils. Dysbiosis caused by antimicrobial use affects responses to chemotherapeutic agents and is prognostic in the development and severity of certain cancer treatment-related complications such as graft-versus-host disease and Clostridioides difficile infections. Studies have also demonstrated that an intact gut microbiota is essential in the anticancer immune response. Antimicrobial use can therefore modulate responses and outcomes with immunotherapy targeting immune checkpoints. In this review, we highlight the perils associated with antimicrobial use during cancer therapy and the importance of a more judicious approach. We discuss the nature of the pathologic changes in the gut microbiota resulting from antimicrobial use. We explore the effect these changes have on responses and outcomes to different cancer treatment modalities including chemotherapy and immunotherapy, as well as potential adverse clinical consequences in the setting of stem cell transplant.

Analysis of Vancomycin-Resistant Enterococci in Hemato-Oncological Patients

Enterococci are important bacterial pathogens, and their significance is even greater in the case of vancomycin-resistant enterococci (VRE). The study analyzed the presence of VRE in the gastrointestinal tract (GIT) of hemato-oncological patients. Active screening using selective agars yielded VRE for phenotypic and genotypic analyses. Isolated strains were identified with MALDI-TOF MS, (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry) their susceptibility to antibiotics was tested, and resistance genes (vanA, vanB, vanC-1, vanC2-C3) and genes encoding virulence factors (asa1, gelE, cylA, esp, hyl) were detected. Pulsed-field gel electrophoresis was used to assess the relationship of the isolated strains. Over a period of three years, 103 VanA-type VRE were identified in 1405 hemato-oncological patients. The most frequently detected virulence factor was extracellular surface protein (84%), followed by hyaluronidase (40%). Unique restriction profiles were observed in 33% of strains; clonality was detected in 67% of isolates. The study found that 7% of hemato-oncological patients carried VRE in their GIT. In all cases, the species identified was Enterococcus faecium. No clone persisted for the entire 3-year study period. However, genetically different clusters were observed for shorter periods of time, no longer than eight months, with identical VRE spreading among patients.

Vancomycin-resistant enterococci infection and predisposing factors for infection and mortality in patients with acute leukaemia and febrile neutropenia

BACKGROUND

Vancomycin-resistant enterococcus (VRE) is an infectious agent that can increase morbidity and mortality, especially in patients with neutropenia in haematology departments. We analysed VRE infections and mortality rates among VRE colonized patients with acute leukaemia, defined predisposing risk factors for infection and mortality, and investigated the influence of daptomycin or linezolid treatment on mortality.

PATIENTS-METHODS

We included 200 VRE colonized adult acute leukaemia patients with febrile neutropenia between January 2010 and January 2016. Data were collected from electronic files.

RESULTS

There were 179 patients in the colonized group, and 21 patients in the infected group. Enterococcus faecium (van A) was isolated from all patients. The infection rate was 10.5 %, and the types of infections noted were as follows: bloodstream (n = 14; 66.7 %), skin and soft tissue (n = 3; 14.3 %), urinary (n = 2; 9.5 %), and others (9.5 %). In the multivariate logistic regression analysis, exposure to invasive procedures, coinfection status, and >15 days of VRE positivity were independent risk factors for VRE infections. In hospital mortality rates were 57.1 % in the infected group, and 9.5 % in the colonized group (p < 0.001). Older age, female gender, absolute neutropenia, and coinfection status were statistically significant predictor of survival.

CONCLUSION

Vancomycin-resistant enterococcus infections are associated with high morbidity and mortality in haematology patients with neutropenia. Clinicians should be aware of predisposing risk factors for VRE infection to avoid unfavourable outcomes. We believe that larger studies are necessary regarding the influence of treatment with daptomycin and linezolid.

Microbiota-based approaches to mitigate infectious complications of intensive chemotherapy in patients with acute leukemia

Despite advances in antimicrobial treatments, infection remains a common complication of intensive chemotherapy in patients with acute leukemia. It has become progressively apparent that the current antimicrobial focus has shortcomings that result from disruption of the commensal microbial communities of the gut. These effects, collectively known as dysbiosis, have been increasingly associated worldwide with growing complications such as Clostridioides difficile infection, systemic infections, and antibiotic resistance. A revision of the current practice is overdue. Several innovative concepts have been proposed and tested in animal models and humans, with the overarching goal of preventing damage to the microbiota and facilitating its recovery. In this review, we discuss these approaches, examine critical knowledge gaps, and explore how they may be filled in future research.

The local hospital milieu and healthcare-associated vancomycin-resistant enterococcus acquisition

BACKGROUND

Vancomycin-resistant enterococcus (VRE) causes 4% of all healthcare-associated infections in the USA. The process by which the local hospital milieu contributes to VRE acquisition is not fully understood.

AIM

To determine the importance of specific factors within the local hospital environment for healthcare-associated VRE acquisition.

METHODS

This retrospective cohort study included patients admitted to six intensive care units at an academic medical centre from January 2012 to December 2016 with negative rectal VRE cultures on admission. VRE acquisition was defined as a positive surveillance swab performed at any time after the initial negative swab during the index hospitalization. The exposures of interest were VRE colonization pressure, VRE importation pressure, and use of vancomycin. Multivariable Cox proportional hazards modelling was performed, with patients followed until VRE acquisition, death, or for up to 30 days.

FINDINGS

Of 8485 patients who were initially VRE negative, 161 patients acquired VRE. On univariate analysis, patients with VRE acquisition were more likely to have received vancomycin, to have had a neighbouring patient who received vancomycin, to have high VRE importation pressure, or to have high VRE colonization pressure. On multivariable analysis, only high VRE colonization pressure was an independent predictor of VRE acquisition (adjusted hazard ratio: 1.79; 95% confidence interval: 1.19-2.70).

CONCLUSION

VRE colonization pressure was the most important risk factor for healthcare-associated VRE acquisition, regardless of VRE importation pressure. Interventions seeking to reduce VRE acquisition should focus on minimizing transmission between patients with known VRE and the local hospital environment.