Fluoroquinolone Prophylaxis Research Articles

Incidence of infection in patients with acute myeloid leukemia receiving high-dose cytarabine consolidation.

Infection risk during high-dose cytarabine (HiDAC) consolidation following induction therapy for acute myeloid leukemia (AML) is not well understood complicating decisions regarding antimicrobial prophylaxis during this period. We performed a retrospective chart review of adult patients with AML undergoing HiDAC consolidation between June 2016 and November 2021 at our institution. The primary endpoint was microbiologically confirmed infection within 30 days of HiDAC administration. This study included 111 patients who received a total of 264 cycles of HiDAC therapy. 36% of patients undergoing HiDAC consolidation had at least 1 infection over the course of their consolidation therapy. Infection complicated 18% of HiDAC cycles. The majority of infections were bacterial (81%), primarily caused by gram-negative organisms. Fluoroquinolone prophylaxis was associated with a lower hazard of bacterial infection (HR 0.46, 95% CI 0.24, 0.88). However, 26% of bacterial infections broke through antibiotic therapy with multiple cases concerning for fluoroquinolone resistance. Viral and fungal infections were rare (14% and 3% of infections respectively).

Impact of discontinuing routine fluoroquinolone prophylaxis in neutropenic allogeneic haematopoietic stem cell transplant recipients: an observational study.

Uncertainty exists as to the role of fluoroquinolone (FQ) prophylaxis for patients undergoing allogeneic haematopoietic stem cell transplantation (HSCT) in the era of rising antibiotic resistance. We aimed to evaluate rates of bloodstream infections (BSI), resistance patterns and outcomes of patients after discontinuing routine FQ prophylaxis administration. All adult recipients of first HSCT from 2017 to 2020 were retrospectively included and classified according to time of HSCT as FQ group (HSCT January 2017-December 2018) or no FQ group (January 2019-December 2020). The primary outcome was Gram-negative (GN) BSI from day -7 to 30 days post-HSCT. The independent association between the study period and BSI was assessed using survival analysis, and adjusting for confounders. We included 254 patients, 130 (51%) and 124 (49%) in the FQ and no FQ groups, respectively. Compared to the FQ group, no FQ had significantly more GN BSI (21% versus 33%, P = 0.027) and the median time to first GN BSI was significantly shorter [4 (IQR 1-8) days versus 6 (1-10) days, P = 0.009]. Following adjustment, FQ prophylaxis remained associated with lower hazard for GN BSI (hazard ratio 0.57, 95% CI 0.34-0.93). Eighty-two GN BSI episodes had FQ susceptibility testing. More GN BSI episodes were FQ resistant in the FQ group (68.9% versus 41.6%, P = 0.021). No significant difference was found for 30-day mortality, time to first febrile neutropenia and time to first broad-spectrum antibiotics between the groups (P was not significant). FQ prophylaxis is associated with fewer GN BSI in the early post-HSCT period even in high FQ resistance settings, with FQ resistance rates reaching >60% following prophylaxis.

Fluoroquinolone Prophylaxis in Children With Cancer: A Pro/Con Discussion.

There are conflicting recommendations on whether to use or not to use fluoroquinolone prophylaxis in pediatric oncology patients. An international pediatric clinical practice guideline (CPG) recommends administering levofloxacin prophylaxis in patients with acute myeloblastic leukemia and relapsed acute lymphoblastic leukemia receiving intensive chemotherapy as this practice has been found to reduce episodes of fever and bacteremia. A separate European CPG does not recommend levofloxacin prophylaxis because of concerns for adverse effects, including potentiation of fluoroquinolone resistance and possible increased resistance to other classes of antibiotics. The nuance of the decision to give or not give prophylaxis is discussed in the context of published evidence defining the risks and benefits of levofloxacin prophylaxis for pediatric leukemia patients at high risk for bacterial infection. Knowledge gaps are also identified to guide further investigations to optimize the use of fluoroquinolone prophylaxis in pediatric patients receiving chemotherapy for cancer or undergoing a hematopoietic cell transplantation.

Ciprofloxacin prophylaxis during haematopoietic cell transplantation: a role for use in patients with germ cell tumours?

Introduction. Fluoroquinolone prophylaxis during haematopoietic cell transplantation (HCT) can lead to antimicrobial resistance (AMR). Identifying the groups of patients that have the highest likelihood of benefiting from prophylactic antimicrobials is important for antimicrobial stewardship (AMS).Hypothesis. We aimed to identify groups of HCT recipients that have the highest likelihood of benefiting from prophylactic fluroquinolones.Methods. All admissions for HCT in a tertiary centre between January 2020 and December 2022 (N = 400) were retrospectively studied. Allogeneic HCT (allo-HCT) recipients had prophylaxis with ciprofloxacin during the chemotherapy-induced neutropenia, while autologous HCT (auto-HCT) recipients did not. Bacteraemias were recorded when non-contaminant bacterial pathogens were isolated in blood cultures.Results. Allo-HCT was performed for 43.3 % (173/400) of patients and auto-HCT was performed for 56.7 % (227/400). A bacteraemia was documented in 28.3 % (113/400) of cases. Allo-HCT recipients were more likely to have a Gram-positive bacteraemia (20.8%, 36/173, vs 10.1%, 23/227, P = 0.03), while a difference was not observed for Gram-negative bacteraemias (18.5%, 32/173 vs 18.1%, 41/227, P = 0.91). Among auto-HCT recipients not receiving ciprofloxacin prophylaxis, patients with germ cell tumours had the highest probability (P for trend 0.09) of recording any bacteraemia (43.5%, 10/23) followed by patients with lymphomas (32.5%, 13/40), other auto-HCT indications (22.2%, 2/9), multiple myeloma (22.1%, 29/131) and multiple sclerosis (12.5%, 3/24). The higher number of bacteraemias in patients with germ cell tumours was primarily driven by Gram-negative pathogens.Conclusions. Ciprofloxacin prophylaxis was associated with a reduced incidence of Gram-negative bacteraemias in allo-HCT recipients. Auto-HCT recipients due to germ cell tumours, not receiving ciprofloxacin prophylaxis, recorded the highest incidence of bacteraemias and represent a possible target group for this intervention.

The addition of doxycycline to fluoroquinolones for bacterial prophylaxis in autologous stem cell transplantation for multiple myeloma.

Bacterial prophylaxis with a fluoroquinolone (FQ) during autologous stem cell transplant (ASCT) is common, although not standardized among transplant centers. The addition of doxycycline (doxy) to FQ prophylaxis was previously linked to reduced neutropenic fever and bacteremia in multiple myeloma (MM) patients undergoing ASCT although several confounders were present. We compared the incidence of neutropenic fever and bacteremia between MM patients variably receiving prophylaxis with FQ alone and FQ-doxy during ASCT. Systematic retrospective chart review of MM patients who underwent ASCT between January 2016 and December 2021. The primary objective was to determine the effect of bacterial prophylaxis on neutropenic fever and bacteremia within 30 days of ASCT. Multivariable logistic regression for neutropenic fever and univariate logistic regression for bacteremia accounted for differences in subject characteristics between groups. Among 341 subjects, 121 received FQ and 220 received FQ-doxy for prophylaxis. Neutropenic fever developed in 67 (55.4%) and 87 (39.5%) subjects in the FQ and FQ-doxy groups, respectively (p=.005). Bacteremia was infrequent, with 5 (4.1%) and 5 (2.3%) cases developing in the FQ and FQ-doxy groups, respectively (p=.337). Among Gram-negative bacteremia events, 7/7 Escherichia coli strains were FQ-resistant, and 5/7 were ceftriaxone-resistant. The FQ-doxy prophylaxis group had fewer cases of neutropenic fever than the FQ group, however, there was no significant difference in bacteremia. High rates of antibiotic resistance were observed. An updated randomized controlled trial investigating appropriate prophylaxis for ASCT in the context of current oncology standards and changing antimicrobial resistance rates is warranted.

BK viral infection: A review of management and treatment.

BK viral infection remains to be a challenging post-transplant infection, which can result in kidney dysfunction. The mainstay approach to BK infection is reduction of immunosuppression. Alterations in immunosuppressive regimen with minimization of calcineurin inhibitors, use of mechanistic target of rapamycin inhibitors, and leflunomide have been attempted with variable outcomes. Over the past few years, investigators have explored potential therapeutic options for BK infection. Fluoroquinolone prophylaxis and treatment was found to have no benefit in kidney transplant recipients. The utility of cidofovir is limited by its nephrotoxicity. Intravenous immunoglobulin is becoming a popular option for treatment and prophylaxis for BK infection, as it increases the neutralizing antibody titers against the most common BK virus serotypes. Virus-specific T cell therapy is an emerging treatment option for BK viremia. In this review, we will explore management and therapeutic options for BK infection and recent evidence available in literature.

Fluoroquinolone-Resistant Enterobacteriaceae Prevalence for Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation (aHSCT) in the Treatment of Multiple Myeloma (MM)

Background: Fluoroquinolones (FQL) are commonly used in antimicrobial prophylaxis in immunocompromised cancer patients (pts) during prolonged neutropenia. A possibly high and increasing proportion of pts harboring FQL-resistant Enterobacteriaceae (FRE) challenges the assumption that prophylaxis with FQLs is still of benefit in preventing sepsis. Previous studies reported that colonization of FRE in allogeneic transplant patients may be an infection risk factor (cf. Satlin et al. Clin Infect Dis 202;73:1257-65). This prospective study aims to determine the prevalence of FRE in defined pt populations in two metropolitan areas treated with dose-intense melphalan with autologous peripheral blood stem cell (PBSC) transplantation, and to determine the possible clinical effects of FRE in the host microbiome on transplant outcomes. Methods: Pts eligible for this prospective, ongoing study have a diagnosis of MM and are undergoing autologous PBSC transplantation after conditioning with dose-intense melphalan 200 mg/m 2 at Hackensack University Medical Center (HUMC) and MedStar Georgetown University Hospital (MGUH). Peri-rectal swabs are scheduled before chemotherapy mobilization of PBSC given with FQL prophylaxis, before transplant admission with initiation of antimicrobial prophylaxis, at time of hospital discharge, and 3 months after aHSCT. Prophylaxis is discontinued with fever or hospital discharge. Blood cultures are obtained at time of fever (>38 °C) with adjustments in antibiotics per standard of care. A central catheter is placed for venous access in all patients throughout their transplant course. Pts are discharged after achieving neutrophil (ANC) engraftment and control of conditioning regimen toxicities. Bacterial cultures from perirectal swabs (fresh or frozen for shipping) were purified on CHROMagar™ Orientation Plates and grown in the presence of ≥5 ug/ml ciprofloxacin to select for quinolone-resistant organisms. Results: To date, 39 pts are evaluable (Table 1). PBSC were mobilized using filgrastim/plerixafor (G-Moz) or cyclophosphamide/etoposide/dexamethasone (CDE) followed by filgrastim with levofloxacin prophylaxis. The quantity of CD34+ cells infused is in Table 1. All pts achieved ANC engraftment at a median of 10.8 days (range 9-14) and were hospitalized for a median of 13 days (range 11-24). 37/39 pts collected swabs before transplant admission (and swabs were obtained at discharge for the other 2 pts). 13/37 (35%) admission swabs demonstrated FRE colonization (Table 2). 6/33 swabs at time of discharge were positive for FRE including for 4 pts negative for FRE on transplant admission with a total of 17/39 pts (44%) showing FRE colonization at some point during the transplant admission. Samples collected at 3 months after transplantation for 24 pts reaching that timepoint showed FRE colonization for 4 pts including 2 pts not previously testing positive at time of transplantation. 27/107 samples tested positive for FRE and 21/39 pts (54%) had at least one FRE positive culture. Seven pts (20%) developed neutropenic fever but no pt experienced a blood-stream infection (BSI). One pt developed Clostridium difficile colitis during the period of neutropenia. One pt tested positive for MRSA colonization at admission but did not develop fever or BSI. One pt was readmitted after initial hospital discharge for evaluation of fever without a source of infection determined. Ten pts (5 FRE colonized during transplant course) were given prednisone for persistent diarrhea attributed to engraftment syndrome (cf: Spitzer TR. Bone Marrow Transplant 2001;27:893-8) commencing at a median of 10 (range, 8-13) days after aHSCT and not associated with CDE mobilization or detection of FRE. Nineteen other patients, 8 of whom tested positive for FRE, did not receive corticosteroids for management of regimen-related toxicities (an additional 7 pts received preplanned corticosteroids starting at day +8). No center effect is yet evident. Conclusions: FRE are detected in a high proportion of pts undergoing aHSCT in the treatment of MM. However, FQL prophylaxis is not associated with FRE BSI in this ongoing study. FRE colonization is not predictive of delayed engraftment or prolonged hospitalization, and does not appear predictive of non-infectious diarrhea.

Global impact of antibacterial resistance in patients with hematologic malignancies and hematopoietic cell transplant recipients.

Patients with hematologic malignancies and hematopoietic cell transplant (HCT) recipients are at high risk of developing bacterial infections. These patients may suffer severe consequences from these infections if they do not receive immediate effective therapies, and thus are uniquely threatened by antimicrobial-resistant bacteria. Here, we outline how the emergence of specific resistant bacteria threatens the effectiveness of established approaches to prevent and treat infections in this population. The emergence of fluoroquinolone resistance among Enterobacterales and viridans group streptococci may decrease the effectiveness of fluoroquinolone prophylaxis during neutropenia. The emergence of Enterobacterales that produce extended-spectrum β-lactamases or carbapenemases and of increasingly resistant Pseudomonas aeruginosa may result in neutropenic patients experiencing delayed time to active antibacterial therapy, and consequently worse clinical outcomes. The ability to select targeted antibacterial therapies after the availability of susceptibility data may be limited in patients infected with metallo-β-lactamase-producing Enterobacterales and difficult-to-treat P. aeruginosa. Vancomycin-resistant enterococci and Stenotrophomonas maltophilia can cause breakthrough infections in patients already being treated with broad-spectrum β-lactam antibiotics. Resistance can also limit the ability to provide oral stepdown antibacterial therapy for patients who could otherwise be discharged from hospitalization. We also outline strategies that have the potential to mitigate the negative impact of antimicrobial resistance, including interventions based on active screening for colonization with resistant bacteria and the use of novel rapid diagnostic assays. Additional research is needed to better understand how these strategies can be leveraged to combat the emerging crisis of antimicrobial resistance in patients with hematologic malignancies and HCT recipients.

Antimicrobial Prophylaxis in Lymphoma by Chemotherapy Regimen

Treatment of lymphomas involves a wide variety of chemotherapy, immunotherapy, and targeted-agents tailored to disease biology and patient characteristics. Each of these regimens carry their own risk of opportunistic infections in an immunocompromised population. In addition to the treatment associated immunosuppression, lymphoma itself is immunosuppressive. Lymphoma associated immunosuppression is secondary to increased production of abnormal lymphocytes resulting in decreased production of normally functioning lymphocytes. Additionally, lymphoma cells induce both humoral and cellular immunosuppression through effects on numerous cytokines, T-cells, myeloid-derived suppressor cells, and macrophages. Clinical trials, patient co-morbidities, and institutional preferences all play a role in determining the preferred antimicrobial prophylaxis. While there is a paucity of data on systematic reviews and guidelines for standardized chemotherapy regimens in lymphoma patients, the efficacy and recommendations for antimicrobial prophylaxis in specific chemotherapy regimens for lymphoma has not been fully reviewed. According to the National Comprehensive Cancer Network, lymphoma is generally regarded as an ‘intermediate risk’ cancer with regards to overall infection risk. This results in discordance between research data and clinical practice. This is reiterated in the SIGNIFICANT trial which reported that while guidelines previously advised against fluoroquinolone prophylaxis in lymphoma and solid cancers, a survey of 3,600 physicians revealed that 45% routinely used fluoroquinolone prophylaxis despite these recommendations. This review article analyzes numerous research studies with summarization of findings and antimicrobial prophylaxis recommendations based on specific lymphoma chemotherapy regimens. With regards to each specific chemotherapy regimen assessed, indications for antibacterial, anti-viral, anti-fungal, and Pneumocystis jiroveci pneumonia (PJP) prophylaxis were determined for each regimen. The degree of immunosuppression and the necessary prophylaxis varies across different regimens and lymphoma subgroups; and thus, an individualized approach is necessary to optimize the supportive care during lymphoma treatment.

Priorities and Progress in Gram-negative Bacterial Infection Research by the Antibacterial Resistance Leadership Group.

Addressing the treatment and prevention of antibacterial-resistant gram-negative bacterial infections is a priority area of the Antibacterial Resistance Leadership Group (ARLG). The ARLG has conducted a series of observational studies to define the clinical and molecular global epidemiology of carbapenem-resistant and ceftriaxone-resistant Enterobacterales, carbapenem-resistant Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii, with the goal of optimizing the design and execution of interventional studies. One ongoing ARLG study aims to better understand the impact of fluoroquinolone-resistant gram-negative gut bacteria in neutropenic patients, which threatens to undermine the effectiveness of fluoroquinolone prophylaxis in these vulnerable patients. The ARLG has conducted pharmacokinetic studies to inform the optimal dosing of antibiotics that are important in the treatment of drug-resistant gram-negative bacteria, including oral fosfomycin, intravenous minocycline, and a combination of intravenous ceftazidime-avibactam and aztreonam. In addition, randomized clinical trials have assessed the safety and efficacy of step-down oral fosfomycin for complicated urinary tract infections and single-dose intravenous phage therapy for adult patients with cystic fibrosis who are chronically colonized with P. aeruginosa in their respiratory tract. Thus, the focus of investigation in the ARLG has evolved from improving understanding of drug-resistant gram-negative bacterial infections to positively affecting clinical care for affected patients through a combination of interventional pharmacokinetic and clinical studies, a focus that will be maintained moving forward.

Fluoroquinolone prophylaxis in patients with neutropenia at high risk of serious infections: Exploring pros and cons.

The use of fluoroquinolones to prevent infections in neutropenic patients with cancer or undergoing hematopoietic stem cell transplantation (HSCT) is a controversial issue, with international guidelines providing conflicting recommendations. Although potential benefits are clear, concerns revolve around efficacy, potential harms, and antimicrobial resistance (AMR) implications. Fluoroquinolone prophylaxis reduces neutropenic fever (NF) bloodstream infections and other serious bacterial infections, based on evidence from systematic reviews, randomized controlled trials, and observational studies in adults and children. Fluoroquinolone prophylaxis may also reduce infection-related morbidity and healthcare costs; however, evidence is conflicting. Adverse effects of fluoroquinolones are well recognized in the general population; however, studies in the cancer cohort where it is used for a defined period of neutropenia have not reflected this. The largest concern for routine use of fluoroquinolone prophylaxis remains AMR, as many, but not all, observational studies have found that fluoroquinolone prophylaxis might increase the risk of AMR, and some studies have suggested negative impacts on patient outcomes as a result. The debate surrounding fluoroquinolone prophylaxis calls for individualized risk assessment based on patient characteristics and local AMR patterns, and prophylaxis should be restricted to patients at the highest risk of serious infection during the highest risk periods to ensure that the risk-benefit analysis is in favor of individual and community benefit. More research is needed to address important unanswered questions about fluoroquinolone prophylaxis in neutropenic patients with cancer or receiving HSCT.

Nonrestrictive diet does not increase infections during post-HSCT neutropenia: data from a multicenter randomized trial

AbstractInfections are a major cause of morbidity and mortality during neutropenia after hematopoietic stem cell transplantation (HSCT). The use of a low-microbial protective diet (PD) in the peritransplantation period is a standard of care, although its efficacy has never been tested prospectively. We conducted a multicenter, randomized, noninferiority trial, enrolling all consecutive adult patients undergoing high-dose induction chemotherapy or HSCT with the objective to compare nonrestrictive diet (NRD) vs PD. Overall, 222 patients were enrolled, randomly assigned, and analyzed. One hundred seventy-five subjects (79%) received autologous HSCT (auto-HSCT), 41 (18%) received allogeneic HSCT (allo-HSCT), and 6 (3%) patients received high-dose induction chemotherapy. There was no significant difference in terms of incidence of grade ≥2 infections and death during neutropenia in the 2 arms. In multivariable analysis, only multiple myeloma diagnosis, fluoroquinolone prophylaxis, and the absence of mucositis were associated with a lower incidence of grade ≥2 infections. We did not report any significant variation in terms of hospitalization length, incidence of mucositis and gastrointestinal infections, body weight, and serum albumin variations in the 2 arms. In allo-HSCT recipients, the incidence of acute graft-versus-host disease grade ≥3 was similar. NRD was associated with higher patient-reported satisfaction. In conclusion, NRD is not inferior to a traditional PD during neutropenia after HSCT, and our results demonstrated that implementing a restrictive diet unnecessary burdens patients' quality of life. The clinical trial was registered prospectively in the clinical trial registry of the Istituto Nazionale dei Tumori of Milan as INT54/16.

Antibiotic practice and stewardship in the management of neutropenic fever: A survey of US institutions

Background: Neutropenic fever management decisions are complex and result in prolonged duration of broad-spectrum antibiotics. Strategies for antibiotic stewardship in this context have been studied, including de-escalation of antibiotics prior to resolution of neutropenia, with unclear implementation. Here, we present the first survey study to describe real-world neutropenic fever management practices in US healthcare institutions, with particular emphasis on de-escalation strategies after initiation of broad-spectrum antibiotics. Methods: Using REDCap, we conducted a survey of US healthcare institutions through the SHEA Research Network (SRN). Questions pertained to antimicrobial prophylaxis and supportive care in the management of oncology patients and neutropenic fever management (including specific antimicrobial choices and clinical scenarios). Hematologic malignancy hospitalization (2020) and bone-marrow transplantation (2016–2020) volumes were obtained from CMS and Health Resources & Services Administration databases, respectively. Results: Overall, 23 complete responses were recorded (response rate, 35.4%). Collectively, these entities account for ~11.0% of hematologic malignancy hospitalizations and 13.3% bone marrow transplantations nationwide. Of 23 facilities, 19 had institutional guidelines for neutropenic fever management and 18 had institutional guidelines for prophylaxis, with similar definitions for neutropenic fever. Firstline treatment universally utilized antipseudomonal broad-spectrum IV antibiotics (20 of 23 use cephalosporin, 3 of 23 use penicillin agent, and no respondents use carbapenem). Fluoroquinolone prophylaxis was common for leukemia induction patients (18 of 23) but was mixed for bone-marrow transplantation (10 of 23). We observed significant heterogeneity in treatment decisions. For stable neutropenic fever patients with no clinical source of infection identified, 13 of 23 respondents continued IV antibiotics until ANC (absolute neutrophil count) recovery. The remainder had criteria for de-escalation back to prophylaxis prior to this (eg, a fever-free period). Respondents were more willing to de-escalate prior to ANC recovery in patients with identified clinical sources (14 of 23 de-escalations in patients with pneumonia) or microbiological sources (15 of 23 de-escalations in patients with bacteremia) after dedicated treatment courses. In free-text responses, several respondents described opportunities for more systemic de-escalation for antimicrobial stewardship in these scenarios. Conclusions: Our results illustrate the real-world management of neutropenic fever in US hospitals, including initiation of therapy, prophylaxis, and treatment duration. We found significant heterogeneity in de-escalation of empiric antibiotics relative to ANC recovery, highlighting a need for more robust evidence for and adoption of this practice.Disclosures: None

Impact of fluoroquinolone administration and gut mucosal colonization on the risk of pre-engraftment bloodstream infections after allogeneic hematopoietic cell transplantation

Fluoroquinolones (FQ) has been used after allogeneic hematopoietic stem cell transplantation (allo-HCT) for decades. This study on 284 allo-HCT recipients aimed to analyze the impact of FQ on pre-engraftment BSI. A total of 154 patients were colonized with resistant gram-negative bacteria, and 130 patients were not. Colonized patients did not receive FQ (n = 147) except 7 who received FQ as sequential therapy; 98 non-colonized patients received FQ, whereas 32 did not. Gram-negative (p < 0.0001), and ESBL-E BSI (p < 0.0001) were higher in colonized patients receiving FQ. No difference was found in gram-positive BSI (p = 0.452). In multivariate analysis colonized patients with (p < 0.0001) or without FQ (p = 0.007), omission of FQ in non-colonized patients (p = 0.038), and active disease (p = 0.042) were associated with gram-negative BSI, whereas mismatched unrelated donor transplantations - with gram-positive BSI (p = 0.009). Colonized patients with FQ have a higher risk of gram-negative BSI. In non-colonized patients, FQ prophylaxis is effective approach significantly reducing gram-negative BSI risk.

Bloodstream infections due to Gram-negative bacteria in patients with hematologic malignancies: updated epidemiology and risk factors for multidrug-resistant strains in an Italian perspective survey

Bloodstream infections (BSI) caused by Gram-negative bacteria (GNB) in patients with hematological malignancies (HM) have been associated with high mortality rates, particularly with infections caused by antibiotic-resistant strains.A multicenter cohort study including all consecutive episodes of GNB BSI in HM patients was conducted to update the epidemiology and antibiotic resistance patterns (compared to our previous survey conducted between 2009 and 2012) and investigate risk factors for GNB BSI due to multidrug-resistant (MDR) isolates.A total of 834 GNB were recovered in 811 BSI episodes from January 2016 to December 2018. Compared to the previous survey, there was a significant reduction in use of fluoroquinolone prophylaxis and a significant recovery in susceptibility rates to ciprofloxacin among Pseudomonas aeruginosa, Escherichia coli and Enterobacter cloacae isolates. In addition, there was a shift to a significantly increased susceptibility of P. aeruginosa isolates to ceftazidime, meropenem, and gentamicin. A total of 256/834 (30.7%) isolates were MDR. In multivariable analysis, MDR bacteria culture-positive surveillance rectal swabs, previous therapy with aminoglycosides and carbapenems, fluoroquinolone prophylaxis, and time at risk were independently associated with MDR GNB BSI.In conclusion, despite the persistence of a high prevalence of MDR GNB, there was a shift to a reduced use of fluoroquinolone prophylaxis and increased rates of susceptibility to fluoroquinolones in almost all isolates and to almost all antibiotics tested among P. aeruginosa isolates, compared to our previous survey. Fluoroquinolone prophylaxis and previous rectal colonization by MDR bacteria were independent risk factors for MDR GNB BSI in the present study.

Cost-Effectiveness of Targeted Prophylaxis among Allogenic Stem Cell Transplant Recipients

Bloodstream infections (BSI) are life-threatening complications for onco-hematologic patients. Fluoroquinolones prophylaxis (FQP) was recommended for patients with neutropenia. Later, it was correlated with increased resistance rates among this population and its role became debated. While the role of FQ prophylaxis is still being studied, its cost-effectiveness is also unknown. The objective of this study was to evaluate the costs and effects associated with two alternative strategies (FQP vs. no prophylaxis) for patients with hematological malignancies undergoing allogenic stem cell transplant (HSCT). A decision-tree model was built integrating retrospectively collected data from a single transplant center, part of a tertiary teaching hospital in Northern Italy. Probabilities, costs and effects were considered in the assessment of the two alternative strategies. Probabilities of colonization, BSIs, extended-spectrum beta lactamase (ESBL) and Klebsiella pneumoniae carbapenemase (KPC) BSIs and mortality associated with infection, as well as median duration of length of stay (LOS) were calculated based on data collected between 2013 and 2021. The center applied the strategy of FQP between 2013 and 2016, and of no prophylaxis between 2016 and 2021. Data on 326 patients were collected during the considered time period. Overall, the rates of colonization, BSI, KPC/ESBL BSI, and mortality were 6.8% (95% confidence interval (CI) 2.7-13.5), 42% (9.9-81.4) and 20.72 (16.67-25.26), respectively. A mean bed-day cost of 132€ was estimated. Considering no prophylaxis vs. prophylaxis, the difference in costs ranged between additional 33.61 and 80.59€ per patient, whereas the difference in effects ranged between 0.11 and 0.03 life-years (LYs) lost (around 40 and 11 days). Given the small differences in terms of costs and effects between the two strategies, no prophylaxis seems an appropriate choice. Furthermore, this analysis did not consider the broader effect on hospital ecology of multiple doses of FQP, which could provide further support for the strategy of no prophylaxis. Our results suggest that the necessity for FQP in onco-hematologic setting should be determined based on local antibiotic resistance patterns.

Risk of bloodstream infections in allogeneic hematopoietic cell transplant recipients according to gut mucosal colonization and fluoroquinolone implementation during neutropenia

Background . Higher rate of gram-negative bloodstream infections (BSI) have been recently documented from transplantation centers providing fluoroquinolone (FQ) prophylaxis. Aim . To define the incidence of BSI during neutropenia according to gut mucosal colonization with resistant gramnegative bacteria and FQ administration. Materials and methods . Of 284 allogeneic hematopoietic cell transplant recipients included in the study, 154 (54.2 %) were identified as colonized with resistant gram-negative bacteria, and 130 (45.8 %) patients as non-colonized. Resistant gram-negative bacteria included Enterobacterales with extended spectrum beta-lactamase production, carbapenem-resistant Enterobacterales, Stenotrophomonas maltophilia , and carbapenem-resistant strains of Pseudomonas aeruginosa . Colonized patients did not receive FQ prophylaxis (n = 147) except 7 patients who received FQ as sequential therapy due to residual inflammatory lung lesions. Among non-colonized patients 98 received FQ prophylaxis, whereas 32 did not. Results . Probability of gram-negative BSI (71.4 %; p &lt;0.0001), and extended spectrum beta-lactamase-producing Enterobacterales BSI (57.1 %; p &lt;0.0001) was significantly higher in colonized patients receiving FQ. No significant difference was found in probability of gram-positive BSI (p = 0.452). In multivariate analysis colonized patients with (hazard ratio (HR) 35.32; 95 % confidence interval (CI) 9.15–136.44; p &lt;0.0001) or without FQ (HR 3.44; 95 % CI 1.15–10.31; p = 0.007), omission of FQ in non-colonized patients (HR 4.03; 95 % CI 1.08–15.00; p = 0.038), and active disease before allogeneic hematopoietic cell transplantation (HR 2.17; 95 % CI 1.03–4.63; p = 0.042) were associated with higher risk of gram-negative BSI, whereas mismatched unrelated donor transplantations were associated with higher gram-positive BSI risk (HR 3.84; 95 % CI 1.63–9.08; p = 0,009). Conclusion . Colonization with multiresistant gram-negative bacteria is a predictor of gram-negative BSI, including multiresistant pathogens, especially when FQ are prescribed during neutropenia, while in non-colonized patients FQ prophylaxis is an effective approach significantly reducing gram-negative BSI.

Bacterial Bloodstream Infections after Allogeneic Hematopoietic Stem Cell Transplantation: Etiology, Risk Factors and Outcome in a Single-Center Study.

We performed an observational, retrospective, single-center study on patients undergoing allo-HSCT between 2004 and 2020 at the Stem Cell Transplant Unit in Turin to assess the incidence, etiology, and outcomes of BSIs and to explore any risk factors for bacteriaemia. We observed a total of 178 bacterial BSIs in our cohort of 563 patients, resulting in a cumulative incidence of 19.4%, 23.8%, and 28.7% at 30, 100, and 365 days, respectively. Among isolated bacteria, 50.6% were Gram positive (GPB), 41.6% were Gram negative (GNB), and 7.9% were polymicrobial infections. Moreover, BSI occurrence significantly influenced 1-year overall survival. High and very high Disease Risk Index (DRI), an haploidentical donor, and antibacterial prophylaxis were found as results as independent risk factors for bacterial BSI occurrence in multivariate analysis. In our experience, GNB have overwhelmed GPB, and fluoroquinolone prophylaxis has contributed to the emergence of MDR pathogens. Local resistance patterns and patients' characteristics should therefore be considered for better management of bacteremia in patients receiving an allogeneic HSCT.

Role of fluoroquinolone prophylaxis in allogeneic hematopoietic cell transplantation in regions with a high prevalence of fluoroquinolone resistance.

The role of fluoroquinolone (FQ) prophylaxis in preventing gram-negative bacilli (GNB) bacteremia, graft-versus-host disease (GVHD), and overall survival (OS) after allogeneic hematopoietic cell transplantation (allo-HCT) is debatable and may differ in settings with low and high prevalences of FQ resistance. In this study, we aimed to answer this question in regions with high FQ resistance. This single-center retrospective study included all consecutive allo-HCT recipients aged ≥12 years from 2012 to 2021. Allo-HCT recipients until 2016 were administered FQ prophylaxis (levofloxacin). After 2016, the institutional protocol was modified to no antibiotic prophylaxis. Data were retrieved from patient records for disease and transplant characteristics, the incidence of GNB bacteremia, duration of parenteral antibiotics, hospitalization duration, acute GVHD, and OS. A total of 135 allo-HCT recipients (43 in the FQ-prophylaxis cohort and 92 in the no-antibiotic prophylaxis cohort) were analyzed in this study. The two cohorts were matched for age (median, 26 vs. 24.5 years; p = 0.8). The no-antibiotic prophylaxis cohort had a higher proportion of malignant diagnoses (80% vs. 58%, p = 0.01), haploidentical transplants (46% vs. 14%, p = 0.004), and posttransplant cyclophosphamide exposure (46% vs. 14%, p = 0.003) than did the FQ cohort. Despite this, the incidence of GNB bacteremia was not significantly different between the two cohorts (37% vs. 34%, p = 0.6). There were no differences in parenteral antibiotic use or hospitalization duration, as well as the incidence of acute GVHD (53% vs. 53%, p = 0.3). The 1-year OS was similar between the two cohorts (66% vs. 67%, p = 0.6). This study shows that FQ prophylaxis did not affect the incidence of GNB bacteremia, parenteral antibiotic use, hospitalization duration, acute GVHD, and OS post-allo-HCT.

A protracted outbreak of difficult-to-treat resistant Pseudomonas aeruginosa in a haematology unit: a matched case–control study demonstrating increased risk with use of fluoroquinolone

Between September 2016 and November 2020, 17 cases of difficult-to-treat resistant Pseudomonas aeruginosa (DTR-PA) were reported in haematology patients at a tertiary referral hospital in the North of England. A retrospective case-control study was conducted to investigate the association between DTR-PA infection and clinical interventions, patient movement, antimicrobial use and co-morbidities. Cases were patients colonised or infected with the outbreak strain of DTR-PA who had been admitted to hospital prior to their positive specimen. A retrospective matched case-control study was performed. Exposures were extracted from medical records and cases were compared to controls using conditional logistic regression. Environmental and microbiological investigations were also conducted. 17 cases and 51 controls were included. The final model included age (>65,aOR 6.85,p=0.232), sex (aOR 0.60,p=0.688), admission under the transplant team (aOR 14.27,p=0.43) and ciprofloxacin use (aOR 102.13,p=0.030). Investigations did not indicate case-to-case transmission or a point source, although a common environmental source was highly likely. This study demonstrates fluoroquinolone use as an independent risk factor for DTR-PA in haematology patients. Antimicrobial stewardship and review of fluoroquinolone prophylaxis should be considered as part of PA outbreak investigations in addition to standard infection control interventions.