Antimicrobial Stewardship in Cancer Patients: The Time is Now

Prospective External Validation of the Esbenshade Vanderbilt Models Accurately Predicts Bloodstream Infection Risk in Febrile Non-Neutropenic Children With Cancer

PURPOSE

The optimal management of fever without severe neutropenia (absolute neutrophil count [ANC] ≥500/µL) in pediatric patients with cancer is undefined. The previously proposed Esbenshade Vanderbilt (EsVan) models accurately predict bacterial bloodstream infections (BSIs) in this population and provide risk stratification to aid management, but have lacked prospective external validation.

MATERIALS AND METHODS

Episodes of fever with a central venous catheter and ANC ≥500/µL occurring in pediatric patients with cancer were prospectively collected from 18 academic medical centers. Variables included in the EsVan models and 7-day clinical outcomes were collected. Five versions of the EsVan models were applied to the data with calculation of C-statistics for both overall BSI rate and high-risk organism BSI (gram-negative and Staphylococcus aureus BSI), as well as model calibration.

RESULTS

In 2,565 evaluable episodes, the BSI rate was 4.7% (N = 120). Complications for the whole cohort were rare, with 1.1% (N = 27) needing intensive care unit (ICU) care by 7 days, and the all-cause mortality rate was 0.2% (N = 5), with only one potential infection-related death. C-statistics ranged from 0.775 to 0.789 for predicting overall BSI, with improved accuracy in predicting high-risk organism BSI (C-statistic 0.800-0.819). Initial empiric antibiotics were withheld in 14.9% of episodes, with no deaths or ICU admissions attributable to not receiving empiric antibiotics.

CONCLUSION

The EsVan models, especially EsVan2b, perform very well prospectively across multiple academic medical centers and accurately stratify risk of BSI in episodes of non-neutropenic fever in pediatric patients with cancer. Implementation of routine screening with risk-stratified management for non-neutropenic fever in pediatric patients with cancer could safely reduce unnecessary antibiotic use.

An Overview of Selected Bacterial Infections in Cancer, Their Virulence Factors, and Some Aspects of Infection Management

In cancer development and its clinical course, bacteria can be involved in etiology and secondary infection. Regarding etiology, various epidemiological studies have revealed that Helicobacter pylori can directly impact gastric carcinogenesis. The Helicobacter pylori-associated virulence factor cytotoxin-associated gene A perhaps plays an important role through different mechanisms such as aberrant DNA methylation, activation of nuclear factor kappa B, and modulation of the Wnt/β-catenin signaling pathway. Many other bacteria, including Salmonella and Pseudomonas, can also affect Wnt/β-catenin signaling. Although Helicobacter pylori is involved in both gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma, its role in the latter disease is more complicated. Among other bacterial species, Chlamydia is linked with a diverse range of diseases including cancers of different sites. The cellular organizations of Chlamydia are highly complex. Interestingly, Escherichia coli is believed to be associated with colon cancer development. Microorganisms such as Escherichia coli and Pseudomonas aeruginosa are frequently isolated from secondary infections in cancer patients. In these patients, the common sites of infection are the respiratory, gastrointestinal, and urinary tracts. There is an alarming rise in infections with multidrug-resistant bacteria and the scarcity of suitable antimicrobial agents adversely influences prognosis. Therefore, effective implementation of antimicrobial stewardship strategies is important in cancer patients.

Evaluation of antibiotic appropriateness at an outpatient oncology centre

Current evidence supporting antimicrobial stewardship programs focused largely in inpatient setting. With the shift in cancer management from inpatient to ambulatory setting, it is crucial to examine the prevalence and predictors of inappropriate antibiotics prescribing. This is a retrospective cross-sectional study conducted at the National Cancer Centre Singapore (NCCS). Patients at least 21 years, with an active or past cancer diagnosis and prescribed with at least one oral antibiotic by a NCCS physician from 1st July to 30th September 2019 were included. Antibiotic appropriateness was assessed using institutional antibiotic guidelines or published clinical practice guidelines. For cases where antibiotics appropriateness cannot be ascertained using these guidelines, an independent three-member expert panel was consulted. A total of 815 patients were screened; 411 (59.4% females) were included with mean age of 62.4 years. The top three cancer diagnoses were breast (26.5%), lung (15.6%) and head and neck (13.6%). More than half (58.6%) received appropriate antibiotic choice. Of which, 235 (97.5%), 238 (98.8%) and 194 (80.5%) received appropriate dose, frequency and duration respectively. The presence of non-oncologic immunosuppressive comorbidities (OR 4.890, 95% CI 1.556-15.369, p-value = 0.007), antibiotic allergy (OR 2.352, 95% CI 1.178-4.698, p-value = 0.015) and skin and soft tissue infections (OR 2.004, 95% CI 1.276-3.146, p-value = 0.003) were associated with a higher incidence of inappropriate antibiotic choice. This study highlighted that inappropriate antibiotic prescribing is prevalent in the ambulatory oncology setting. Predicators identified can aid in the design of targeted strategies to optimise antibiotic use in ambulatory oncology patients.

Challenges and Opportunities in Antimicrobial Stewardship among Hematopoietic Stem Cell Transplant and Oncology Patients

Antimicrobial stewardship programs play a critical role in optimizing the use of antimicrobials against pathogens in the era of growing multi-drug resistance. However, implementation of antimicrobial stewardship programs among the hematopoietic stem cell transplant and oncology populations has posed challenges due to multiple risk factors in the host populations and the infections that affect them. The consideration of underlying immunosuppression and a higher risk for poor outcomes have shaped therapeutic decisions for these patients. In this multidisciplinary perspective piece, we provide a summary of the current landscape of antimicrobial stewardship, unique challenges, and opportunities for unmet needs in these patient populations.

Monitoring and Modulating Diet and Gut Microbes to Enhance Response and Reduce Toxicity to Cancer Treatment

The gut microbiome comprises a diverse array of microbial species that have been shown to dynamically modulate host immunity both locally and systemically, as well as contribute to tumorigenesis. In this review, we discuss the scientific evidence on the role that gut microbes and diet play in response and toxicity to cancer treatment. We highlight studies across multiple cancer cohorts that have shown an association between particular gut microbiome signatures and an improved response to immune checkpoint blockade, chemotherapy, and adoptive cell therapies, as well as the role of particular microbes in driving treatment-related toxicity and how the microbiome can be modulated through strategies, such as fecal transplant. We also summarize the current literature that implicate high fiber and ketogenic diets in improved response rates to immunotherapy and chemotherapy, respectively. Finally, we discuss the relevance of these findings in the context of patient care, advocate for a holistic approach to cancer treatment, and comment on the next frontier of targeted gut and tumor microbiome modulation through novel therapeutics, dietary intervention, and precision-medicine approaches.

Cancer is chronic but antimicrobial stewardship is iconic: A retrospective cohort of optimal antibiotic use in ambulatory oncology clinics

Objective

To evaluate antibiotic prescribing in ambulatory oncology clinics and to identify opportunities to improve antibiotic use.

Methods

Retrospective cohort of adult patients who received care at 4 ambulatory oncology clinics from May 2021 to December 2021. Patients were included if they actively followed with a hematologist-oncologist for a cancer diagnosis and received an antibiotic prescription for uncomplicated upper respiratory tract infection (URTI), lower respiratory tract infection (LRTI), urinary tract infection (UTI), or acute bacterial skin-skin structure infection (ABSSSI) at an oncology clinic. The primary outcome was receipt of optimal antibiotic therapy, defined as a composite of drug, dose, and duration according to local and national guidelines. Patient characteristics were described and compared; predictors of optimal antibiotic use were identified using multivariable logistic regression.

Results

In total, 200 patients were included in this study: 72 (36%) received optimal antibiotics and 128 (64%) received suboptimal antibiotics. The proportions of patients receiving optimal therapy by indication were ABSSSI (52%), UTI (35%), URTI (27%), and LRTI (15%). The most common suboptimal prescribing components were dose (54%), selection (53%) and duration (23%). After adjusting for female sex and LRTI, ABSSSI (adjusted odds ratio, 2.28; 95% confidence interval, 1.19-4.37) was associated with optimal antibiotic therapy. Antibiotic-associated adverse drug events occurred in 7 patients; 6 occurred patients who received prolonged durations and 1 occurred in a patient who received an optimal duration (P = .057).

Conclusions

Suboptimal antibiotic prescribing in ambulatory oncology clinics is common and mostly driven by antibiotic selection and dosing. Duration of therapy may also be an area for improvement as national oncology guidelines have not adopted short-course therapy.

A contemporary review of Clostridioides difficile infections in patients with haematologic diseases

Clostridioides (Clostridium) difficile (C. difficile) infection is one of the most common causes of increased morbidity and mortality. Approximately 500 000 C. difficile infections (CDIs) occur each year in the United States, and they result in more than 29 000 deaths. Patients with haematologic diseases are at a higher risk for this infection due to frequent hospitalization and exposure to treatment-associated risk factors. Whilst several currently available antimicrobial agents offer resolution, recurrence of infection remains a major concern. Recent advancement in deciphering C. difficile virulence mechanisms and identification of its allies in contributing to the infection has led to the development of alternative treatment strategies. Here, we will provide a contemporary discussion of how major risk factors in haematologic diseases, such as immunosuppression, chemoradiation, use of antibiotic, proton pump inhibitor and opioid, and deficiency in butyrate and antimicrobial peptides contribute to C. difficile infection. Next, we will highlight different approaches to control and mitigate this infection such as antibiotic stewardship and faecal microbiota transplantation. Finally, we will explore several emerging treatments such as use of pre- and probiotics, immunotherapy and microbiome-sparing agents.

Inpatient Antibiotic Stewardship Interventions in the Adult Oncology and Hematopoietic Stem Cell Transplant Population: A Review of the Literature

Objective: To review the use of antibiotic stewardship interventions in the adult oncology and hematopoietic cell transplantation (HCT) populations. Data Sources: A literature search of PubMed was performed from inception to October 31, 2019. The general search terms used were oncology, cancer, hematologic malignancy, antimicrobial stewardship, antibiotic stewardship, febrile neutropenia, neutropenic fever, de-escalation, discontinuation, prophylaxis, practice guidelines, clinical pathway, rapid diagnostics, Filmarray, Verigene, MALDI-TOF, antibiotic allergy, and antimicrobial resistance. Study Selection and Data Extraction: Relevant English-language studies describing interventions supported by the Infectious Diseases Society of America guidelines on "Implementing an Antibiotic Stewardship Program" were included. Data Synthesis: Antibiotic stewardship publications in the oncology population have increased in recent years. Studies have described the impact of stewardship interventions, including preauthorization, prospective audit and feedback, implementation of clinical pathways, de-escalation of empirical antibiotics for febrile neutropenia (FN) prior to neutrophil recovery, allergy assessments, and use of rapid diagnostic testing. Many of these interventions have been shown to decrease antibiotic use without increased negative consequences, such as affecting length of stay or mortality. Relevance to Patient Care and Clinical Practice: This review synthesizes available evidence for implementing antibiotic stewardship interventions, particularly de-escalation of antibiotics for FN and implementation of clinical pathways for FN and sepsis, in oncology patients and HCT recipients. Summary tables highlight studies and specific research needs for clinicians. Conclusions: Immunocompromised populations, including oncology patients, have often been excluded from stewardship studies. Antibiotic stewardship is effective in reducing antibiotic consumption and improving outcomes in this patient population, although more quality data are needed.