Food Insecurity in the Elective Enhanced Recovery After Surgery Colorectal Surgical Population: Prevalence and Implications for Surgical Outcomes.

BACKGROUND: Food insecurity is defined as having limited or uncertain availability of nutritionally adequate food. Approximately 10.5% of U.S. households are food-insecure. Our study aimed to determine the prevalence and postoperative implications of food insecurity in a diverse group of colorectal surgery patients admitted to a hospital in an area with a higher-than-average median income. METHODS: The 6-question Household Food Security Survey was added to the colorectal surgery ERAS program preoperative paperwork. Patient demographics, comorbidities, operative parameters, length of stay, and postoperative outcomes were collected by review of electronic medical records. RESULTS: A total of 294 ERAS patients (88.8%) completed the survey over an 11-month period. Thirty-three patients (11.2%) were identified as food-insecure. Food-insecure patients were more likely to be non-white (P = .003), younger (P = .009), smokers (P = .004), chronic narcotic users (P < .001), unmarried (P = .007), and have more comorbidities (P = .004). The food-insecure population had more frequent postoperative ileus (P = .044). Hospital length of stay was significantly longer in food-insecure patients (8.6 days vs 5.4 days, P < .001). Food-insecure patients also had higher rates of >30-day mortality (P = .049). DISCUSSION: Food insecurity was found to occur in patients that lived in communities deemed both affluent and distressed. These patients had longer hospital stays and higher mortality. A food insecurity questionnaire can easily identify patients at risk. Further investigations to mitigate these complications are warranted.

Predictive factors of first-time failure on the American Board of Colorectal Surgery certifying and qualifying examinations.

Objective: To discover if first-attempt failure of the American Board of Colon and Rectal Surgery (ABCRS) board examination is associated with surgical training or personal demographic characteristics. Methods: Current colon and rectal surgery program directors in the United States were contacted via email. Deidentified records of trainees from 2011 to 2019 were requested. Analysis was performed to identify associations between individual risk factors and failure on the ABCRS board examination on the first attempt. Results: Seven programs contributed data, totaling 67 trainees. The overall first-time pass rate was 88% (n = 59). Several variables demonstrated potential for association, including Colon and Rectal Surgery In-Training Examination (CARSITE) percentile (74.5 vs 68.0, P = 0.09), number of major cases in colorectal residency (245.0 vs 219.2, P = 0.16), >5 publications during colorectal residency (75.0% vs 25.0%, P = 0.19), and first-time passage of the American Board of Surgery certifying examination (92.5% vs 7.5%, P = 0.18). Conclusion: The ABCRS board examination is a high-stakes test, and training program factors may be predictive of failure. Although several factors showed potential for association, none reached statistical significance. Our hope is that by increasing our data set, we will identify statistically significant associations that can potentially benefit future trainees in colon and rectal surgery.

Central Line-Associated Bloodstream Infection in Patients With Hematologic Malignancy Receiving Parenteral Nutrition.

PURPOSE: Parenteral nutrition (PN) has been shown to be a safe method of feeding in the intensive care unit with modern infection prevention practices, but similar analysis in the hematology-oncology setting is lacking. METHODS: A retrospective analysis of 1,617 patients with hematologic malignancies admitted and discharged from the Hospital of the University of Pennsylvania during 3,629 encounters from 2017 to 2019 was undertaken to evaluate the association of PN administration with risk of central line-associated bloodstream infection (CLABSI). Proportions of mucosal barrier injury (MBI)-CLABSI and non-MBI-CLABSI were also compared between groups. RESULTS: Risk of CLABSI was associated with cancer type and duration of neutropenia but not with PN administration (odds ratio, 1.015; 95% CI, 0.986 to 1.045; P = .305) in a multivariable analysis. MBI-CLABSI comprised 73% of CLABSI in patients exposed to and 70% in patients not exposed to PN, and there was no significant difference between groups (χ2 = 0.06, P = .800). CONCLUSION: PN was not associated with increased risk of CLABSI in a sample of patients with hematologic malignancy with central venous catheters when adjusting for cancer type, duration of neutropenia, and catheter days. The high proportion of MBI-CLABSI highlights the effect of gut permeability within this population.

Clostridioides difficile dynamic electronic order panel, an effective automated intervention to reduce inappropriate inpatient ordering.

BACKGROUND: Ordering Clostridioides difficile diagnostics without appropriate clinical indications can result in inappropriate antibiotic prescribing and misdiagnosis of hospital onset C. difficile infection. Manual processes such as provider review of order appropriateness may detract from other infection control or antibiotic stewardship activities. METHODS: We developed an evidence-based clinical algorithm that defined appropriateness criteria for testing for C. difficile infection. We then implemented an electronic medical record-based order-entry tool that utilized discrete branches within the clinical algorithm including history of prior C. difficile test results, laxative or stool-softener administration, and documentation of unformed bowel movements. Testing guidance was then dynamically displayed with supporting patient data. We compared the rate of completed C. difficile tests after implementation of this intervention at 5 hospitals to a historic baseline in which a best-practice advisory was used. RESULTS: Using mixed-effects Poisson regression, we found that the intervention was associated with a reduction in the incidence rate of both C. difficile ordering (incidence rate ratio [IRR], 0.74; 95% confidence interval [CI], 0.63-0.88; P = .001) and C. difficile-positive tests (IRR, 0.83; 95% CI, 0.76-0.91; P < .001). On segmented regression analysis, we identified a sustained reduction in orders over time among academic hospitals and a new reduction in orders over time among community hospitals. CONCLUSIONS: An evidence-based dynamic order panel, integrated within the electronic medical record, was associated with a reduction in both C. difficile ordering and positive tests in comparison to a best practice advisory, although the impact varied between academic and community facilities.

Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) surface contamination in staff common areas and impact on healthcare worker infection: Prospective surveillance during the coronavirus disease 2019 (COVID-19) pandemic.

We prospectively surveyed SARS-CoV-2 RNA contamination in staff common areas within an acute-care hospital. An increasing prevalence of surface contamination was detected over time. Adjusting for patient census or community incidence of coronavirus disease 2019 (COVID-19), the proportion of contaminated surfaces did not predict healthcare worker COVID-19 infection on study units.

Perioperative Lidocaine Infusion Reduces Opioid Use in Enhanced Recovery After Surgery Patients Undergoing Laparoscopic Colectomy.

BACKGROUND: Enhanced Recovery After Surgery (ERAS) programs have become a mainstay of modern surgical care, and efforts to decrease postoperative opioid consumption have been increasingly employed. A previous study from our institution demonstrated that ERAS protocols decreased opioid use in the first 48 hours after surgery by 61%. In the present study, a lidocaine infusion was added for postoperative pain control. The aim was to analyze the differences in opioid requirements with and without this infusion in the first 48 hours after laparoscopic colectomy in ERAS patients. METHODS: Retrospective review of patients was conducted at an academically affiliated tertiary care hospital. The population included patients undergoing elective laparoscopic colon surgery enrolled in the ERAS program with the implementation of a lidocaine drip from June 2019 to October 2019, and compared to a previous patient cohort of ERAS patients evaluated without the lidocaine drip from September 2015 to May 2018. RESULTS: The primary endpoint was postoperative opioid use in the first 48 hours based on IV morphine milligram equivalents (MME). Secondary measures included type of surgery, age, BMI, prior abdominal surgery, and prior opioid use. Median MMEs were 6.0 in the lidocaine infusion group and 12.5 in the group without lidocaine, representing a 52% reduction (p < 0.001). DISCUSSION: This study demonstrates a significant reduction in post-op opioid use in ERAS patients who receive a lidocaine infusion after laparoscopic colectomy. Further studies should focus on measures to limit the treatment side effects in order to maximize the opioid-sparing benefits of this intervention.

Use of Glucocorticoids in Patients With Cancer: Potential Benefits, Harms, and Practical Considerations for Clinical Practice.

PURPOSE: Glucocorticoids are commonly used in patients with cancer for symptom relief or as part of their anticancer treatment. Despite their frequent use, indications and dosing regimens are not exclusively evidence-based and can come with a multitude of adverse effects, some of which can be life-threatening. The objective of this review is to update our current state of knowledge on the use of glucocorticoids in adult patients with cancer. METHODS AND MATERIALS: A comprehensive literature review (1949-2022) was conducted using search terms "glucocorticoids," "corticosteroids," and "cancer." Information was organized by main concepts including indications, potential benefits, and prevention and management of common side effects of glucocorticoid therapy, in addition to appropriate dosing and taper regimens. RESULTS: Glucocorticoids can be highly effective in improving outcomes and quality of life in patients with cancer. Their uses include management of disease manifestations, symptoms, and complications of cancer treatment. The lowest effective dose should be used and treatment duration should be minimized as clinically feasible. Side effects can be minimized by careful monitoring, continued assessment of benefits versus harms, and preventative measures for expected side effects. CONCLUSIONS: This review provides general principles and practical recommendations on the use of glucocorticoids in patients with cancer. Further prospective studies on the outcomes of patients on glucocorticoids may help guide practice.

SARS-CoV-2 RNA persists on surfaces following terminal disinfection of COVID-19 hospital isolation rooms.

We evaluated the effect of terminal cleaning on SARS-CoV-2 RNA contamination of COVID-19 isolation rooms in an acute care hospital. SARS-CoV-2 RNA was detected on 32.1% of room surfaces after cleaning; the odds of contamination increased with month. The prevalence of elevated high-touch surface contamination was lower in terminally cleaned rooms than patient-occupied rooms.

Stopping Hospital Infections With Environmental Services (SHINE): A Cluster-randomized Trial of Intensive Monitoring Methods for Terminal Room Cleaning on Rates of Multidrug-resistant Organisms in the Intensive Care Unit.

BACKGROUND: Multidrug-resistant organisms (MDROs) frequently contaminate hospital environments. We performed a multicenter, cluster-randomized, crossover trial of 2 methods for monitoring of terminal cleaning effectiveness. METHODS: Six intensive care units (ICUs) at 3 medical centers received both interventions sequentially, in randomized order. Ten surfaces were surveyed each in 5 rooms weekly, after terminal cleaning, with adenosine triphosphate (ATP) monitoring or an ultraviolet fluorescent marker (UV/F). Results were delivered to environmental services staff in real time with failing surfaces recleaned. We measured monthly rates of MDRO infection or colonization, including methicillin-resistant Staphylococcus aureus, Clostridioides difficile, vancomycin-resistant Enterococcus, and MDR gram-negative bacilli (MDR-GNB) during a 12-month baseline period and sequential 6-month intervention periods, separated by a 2-month washout. Primary analysis compared only the randomized intervention periods, whereas secondary analysis included the baseline. RESULTS: The ATP method was associated with a reduction in incidence rate of MDRO infection or colonization compared with the UV/F period (incidence rate ratio [IRR] 0.876; 95% confidence interval [CI], 0.807-0.951; P = .002). Including the baseline period, the ATP method was associated with reduced infection with MDROs (IRR 0.924; 95% CI, 0.855-0.998; P = .04), and MDR-GNB infection or colonization (IRR 0.856; 95% CI, 0.825-0.887; P < .001). The UV/F intervention was not associated with a statistically significant impact on these outcomes. Room turnaround time increased by a median of 1 minute with the ATP intervention and 4.5 minutes with UV/F compared with baseline. CONCLUSIONS: Intensive monitoring of ICU terminal room cleaning with an ATP modality is associated with a reduction of MDRO infection and colonization.

Certain Rooms in Intensive Care Units May Harbor Risk for Clostridioides difficile Infection.

Abstract Background: Clostridioides difficile infection (CDI) is a common and sometimes life-threatening illness. Patient-, care-, and room hygiene-specific factors are known to impact CDI genesis, but care provider training and room topography have not been explored. We sought to determine if care in specific intensive care unit (ICU) rooms asymmetrically harbored CDI cases. Patients and Methods: Surgical intensive care unit (SICU) patients developing CDI (July 2009 to June 2018) were identified and separated by service (green/gold). Each service cared for their respective 12 rooms, otherwise differing only in resident team composition (July 2009 to August 2017: green, anesthesia; gold, surgery; August 2017 to June 2018: mixed for both). Fixed/mobile room features and provider traffic in three room zones (far/middle/near in relation to the toilet) were compared between high-/low-incidence rooms using observation via telecritical care video cameras. Results: Seventy-four new CDI cases occurred in 7,834 consecutive SICU admissions. In period one, green CDI cases were almost double gold cases (39 vs. 21; p = 0.02) but were similar in period two in which trainee service allocation intermixed. High-incidence rooms had closer toilet-to-intravenous pole proximity than low-incidence rooms (7.7 + 1.8 feet vs. 3.9 + 1.5 feet; p = 0.02). High-incidence rooms consistently housed mobile objects (patient bed, table-on-wheels) farther away from the toilet. Although physician time spent in each zone was similar, nurses spending more than 15 minutes in-room more frequently stayed in the far/middle zones in high-incidence rooms. Conclusions: Distinct SICU room features relative to toilet location and bedside clinician behaviors interact to alter patient CDI acquisition risk. This suggests that CDI risk occurs as a structural aspect of ICU care, offering the potential to reduce patient risk through deliberate room redesign.

Can the American College of Surgeons National Surgical Quality Improvement Program Risk Calculator Predict Outcomes for Urgent Colectomies?

BACKGROUND: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) Risk Calculator (RC) predicts postoperative outcomes using 19 risk factors, including operative acuity. Acuity is defined by the calculator as emergent or elective only. The objective of this study is to evaluate the RC's accuracy in urgent (nonelective/nonemergent) cases. METHODS: This is a retrospective review of the NSQIP data for patients who underwent urgent colectomies at a single tertiary care center over a 4-year period. Each urgent case was entered into the RC as both elective and emergent, and predicted outcomes were compared to actual postoperative outcomes. Receiver operating characteristic (ROC) curves were used when sufficient statistical power was present and the area under the curve (AUC) was calculated. RESULTS: A total of 301 urgent colectomy patients were evaluated, representing 19% of all colectomies performed at our institution during the study period. Of the 15 possible postoperative outcomes, the RC showed high predictive value only for mortality (AUC elective .8467; emergent .8451) and discharge to a nursing/rehabilitation facility (AUC elective .8089; emergent .8105). The RC showed no predictive value for 6 outcomes and the remainder lacked statistical power to draw conclusions. DISCUSSION: While the calculator predicted mortality and discharge to a nursing/rehabilitation facility, it did not accurately predict complications for urgent colectomies. Future versions of the calculator should focus on improving the predictive value by including urgent cases as a separate category.

Coronavirus disease 2019 (COVID-19) research agenda for healthcare epidemiology.

This SHEA white paper identifies knowledge gaps and challenges in healthcare epidemiology research related to coronavirus disease 2019 (COVID-19) with a focus on core principles of healthcare epidemiology. These gaps, revealed during the worst phases of the COVID-19 pandemic, are described in 10 sections: epidemiology, outbreak investigation, surveillance, isolation precaution practices, personal protective equipment (PPE), environmental contamination and disinfection, drug and supply shortages, antimicrobial stewardship, healthcare personnel (HCP) occupational safety, and return to work policies. Each section highlights three critical healthcare epidemiology research questions with detailed description provided in supplementary materials. This research agenda calls for translational studies from laboratory-based basic science research to well-designed, large-scale studies and health outcomes research. Research gaps and challenges related to nursing homes and social disparities are included. Collaborations across various disciplines, expertise and across diverse geographic locations will be critical.

Healthcare microenvironments define multidrug-resistant organism persistence.

BACKGROUND: Multidrug-resistant organisms (MDROs) colonizing the healthcare environment have been shown to contribute to risk for healthcare-associated infections (HAIs), with adverse effects on patient morbidity and mortality. We sought to determine how bacterial contamination and persistent MDRO colonization of the healthcare environment are related to the position of patients and wastewater sites. METHODS: We performed a prospective cohort study, enrolling 51 hospital rooms at the time of admitting a patient with an eligible MDRO in the prior 30 days. We performed systematic sampling and MDRO culture of rooms, as well as 16S rRNA sequencing to define the environmental microbiome in a subset of samples. RESULTS: The probability of detecting resistant gram-negative organisms, including Enterobacterales, Acinetobacter spp, and Pseudomonas spp, increased with distance from the patient. In contrast, Clostridioides difficile and methicillin-resistant Staphylococcus aureus were more likely to be detected close to the patient. Resistant Pseudomonas spp and S. aureus were enriched in these hot spots despite broad deposition of 16S rRNA gene sequences assigned to the same genera, suggesting modifiable factors that permit the persistence of these MDROs. CONCLUSIONS: MDRO hot spots can be defined by distance from the patient and from wastewater reservoirs. Evaluating how MDROs are enriched relative to bacterial DNA deposition helps to identify healthcare micro-environments and suggests how targeted environmental cleaning or design approaches could prevent MDRO persistence and reduce infection risk.

Spatial and temporal effects on severe acute respiratory coronavirus virus 2 (SARS-CoV-2) contamination of the healthcare environment.

BACKGROUND: The spatial and temporal extent of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) environmental contamination has not been precisely defined. We sought to elucidate contamination of different surface types and how contamination changes over time. METHODS: We sampled surfaces longitudinally within COVID-19 patient rooms, performed quantitative RT-PCR for the detection of SARS-CoV-2 RNA, and modeled distance, time, and severity of illness on the probability of detecting SARS-CoV-2 using a mixed-effects binomial model. RESULTS: The probability of detecting SARS-CoV-2 RNA in a patient room did not vary with distance. However, we found that surface type predicted probability of detection, with floors and high-touch surfaces having the highest probability of detection: floors (odds ratio [OR], 67.8; 95% credible interval [CrI], 36.3-131) and high-touch elevated surfaces (OR, 7.39; 95% CrI, 4.31-13.1). Increased surface contamination was observed in room where patients required high-flow oxygen, positive airway pressure, or mechanical ventilation (OR, 1.6; 95% CrI, 1.03-2.53). The probability of elevated surface contamination decayed with prolonged hospitalization, but the probability of floor detection increased with the duration of the local pandemic wave. CONCLUSIONS: Distance from a patient's bed did not predict SARS-CoV-2 RNA deposition in patient rooms, but surface type, severity of illness, and time from local pandemic wave predicted surface deposition.

Quantifying the Impact of Nasopharyngeal Specimen Quality on Severe Acute Respiratory Syndrome Coronavirus 2 Test Performance.

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse-transcription polymerase chain reaction (RT-PCR) cycle threshold (Ct) has been used to estimate quantitative viral load, with the goal of targeting isolation precautions for individuals with coronavirus disease 2019 (COVID-19) and guiding public health interventions. However, variability in specimen quality can alter the Ct values obtained from SARS-CoV-2 clinical assays. We sought to define how variable nasopharyngeal (NP) swab quality impacts clinical SARS-CoV-2 test sensitivity. METHODS: We performed amplification of a human gene target (ß-actin) in parallel with a clinical RT-PCR targeting the SARS-CoV-2 ORF1ab gene for 1282 NP specimens collected from patients with clinical concern for COVID-19. We evaluated the relationship between NP specimen quality, characterized by late Ct values for the human gene target ß-actin Ct, and the probability of SARS-CoV-2 detection via logistic regression, as well as the linear relationship between SARS-CoV-2 and ß-actin Ct. RESULTS: Low-quality NP swabs are less likely to detect SARS-CoV-2 (odds ratio, 0.607 [95% credible interval {CrI}, .487-.753]). We observed a positive linear relationship between SARS-CoV-2 and ß-actin Ct values (slope, 0.181 [95% CrI, .097-.264]), consistent with a reduction in detection of 0.181 cycles for each additional cycle of the ß-actin target. COVID-19 disease severity was not associated with ß-actin Ct values. CONCLUSIONS: Variability in NP specimen quality significantly impacts the performance of clinical SARS-CoV-2 assays, and caution should be taken when interpreting quantitative SARS-CoV-2 Ct results. If unrecognized, low-quality NP specimens, which are characterized by a low level of amplifiable human DNA target, may limit the successful application of SARS-CoV-2 Ct values to direct infection control and public health interventions.

Opioid Requirements in Laparoscopic Colectomies: Do Enhanced Recovery After Surgery Protocols Make a Difference?

BACKGROUND: With the growing opioid epidemic and recent focus on the quantity of opioids prescribed at discharge after surgery, enhanced recovery pathways provide another tool to counteract this epidemic. The aim of this current study is to analyze the differences in opioid requirements and pain scores in the immediate postoperative period for patients who underwent laparoscopic colectomies before and after the implementation of enhanced recovery after surgery (ERAS) protocols. MATERIALS AND METHODS: This study is a retrospective review of patients and was conducted at an academically affiliated tertiary care hospital. In patients undergoing elective laparoscopic colectomies before December 1, 2013-July 31, 2015 and after September 1, 2015-May 31, 2018, the implementation of enhanced recovery pathways was included. The primary end point was opioid consumption from the end of surgery until 48 hours after surgery. Secondary end points included pain scores, surgery length of time, and hospital length of stay after surgery. RESULTS: A total of 242 patients (122 pre- and 120 postimplementation) were analyzed. Patient characteristics were similar between groups. Pain scores were higher in the preimplementation patients for postoperative day (POD) 0 scores (P = .019). There was a decrease in the morphine milligram equivalents (MME) on POD 0-2 for the postimplementation patients. This decrease resulted in a 61% reduction in opioid requirements after implementation of ERAS protocols (32 vs. 12.5 MME, P < .0001). DISCUSSION: Enhanced recovery after surgery protocols can reduce opioid requirements after elective laparoscopic colectomies without negatively affecting pain scores.

Impact of Nasopharyngeal Specimen Quality on SARS-CoV-2 Test Sensitivity.

BACKGROUND: The SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR) cycle of threshold (Ct) has been used to estimate quantitative viral load, with the goal of targeting isolation precautions for individuals with COVID-19 and guiding public health interventions. However, variability in specimen quality can alter the Ct values obtained from SARS-CoV-2 clinical assays. We sought to define how variable nasopharyngeal (NP) swab quality impacts clinical SARS-CoV-2 test sensitivity. METHODS: We performed amplification of a human gene target (ß-actin) in parallel with a clinical RT-PCR targeting the SARS-CoV-2 ORF1ab gene for 1311 NP specimens collected from patients with clinical concern for COVID-19. We evaluated the relationship between NP specimen quality, characterized by high Ct values for the human gene target ß-actin Ct, and the probability of SARS-CoV-2 detection via logistic regression, as well as the linear relationship between SARS-CoV-2 and ß-actin Ct. RESULTS: Low quality NP swabs are less likely to detect SARS-CoV-2 (odds ratio 0.654, 95%CI 0.523 to 0.802). We observed a positive linear relationship between SARS-CoV-2 and ß-actin Ct values (slope 0.169, 95%CI 0.092 to 0.247). COVID-19 disease severity was not associated with ß-actin Ct values. CONCLUSIONS: Variability in NP specimen quality accounts for significant differences in the sensitivity of clinical SARS-CoV-2 assays. If unrecognized, low quality NP specimens, which are characterized by a low level of amplifiable human DNA target, may limit the application of SARS-CoV-2 Ct values to direct infection control and public health interventions.

Policies and practices of SHEA Research Network hospitals during the COVID-19 pandemic.

To understand hospital policies and practices as the COVID-19 pandemic accelerated, the Society for Healthcare Epidemiology of America (SHEA) conducted a survey through the SHEA Research Network (SRN). The survey assessed policies and practices around the optimization of personal protection equipment (PPE), testing, healthcare personnel policies, visitors of COVID-19 patients in relation to procedures, and types of patients. Overall, 69 individual healthcare facilities responded in the United States and internationally, for a 73% response rate.

Guideline implementation is effective at reducing proton pump inhibitor use in hematology-oncology units: A multidisciplinary intervention for reducing Clostridioides difficile risk.

We implemented a guideline for appropriate acid suppressant use in hematology-oncology patients. This intervention resulted in a sustained reduction in proton pump inhibitor (PPI) use without an increase in rates of gastrointestinal bleeding. Practice guidelines are effective in reducing PPI use, which is associated with risk of Clostridioides difficile infection.

Impact of Levofloxacin for the Prophylaxis of Bloodstream Infection on the Gut Microbiome in Patients With Hematologic Malignancy.

BACKGROUND: We evaluated the differential impact of levofloxacin administered for the prophylaxis of bloodstream infections compared with broad-spectrum beta-lactam (BSBL) antibiotics used for the treatment of neutropenic fever on the gut microbiome in patients with hematologic malignancy. METHODS: Stool specimens were collected from patients admitted for chemotherapy or stem cell transplant in the setting of the evaluation of diarrhea from February 2017 until November 2017. Microbiome characteristics were compared among those exposed to levofloxacin prophylaxis vs those who received BSBL antibiotics. RESULTS: Sixty patients were included, most with acute myeloid leukemia (42%) or multiple myeloma (37%). The gut microbiome of patients with BSBL exposure had significantly reduced Shannon's alpha diversity compared with those without (median [interquartile range {IQR}], 3.28 [1.73 to 3.71] vs 3.73 [3.14 to 4.31]; P = .01). However, those with levofloxacin exposure had increased alpha diversity compared with those without (median [IQR], 3.83 [3.32 to 4.36] vs 3.32 [2.35 to 4.02]; P = .03). Levofloxacin exposure was also associated with a trend toward lower risk of dominance of non-Bacteroidetes genera compared with those without levofloxacin exposure (3 [14%] vs 15 [38%]; P = .051). CONCLUSIONS: The impact of antibiotics on the gut microbiome varies by class, and levofloxacin may disrupt the gut microbiome less than BSBLs in this patient population.