Factors associated with mortality in bacteremic patients with hematologic malignancies

Bloodstream Infections Due to Multidrug-Resistant Gram-Negative Organisms in Hematopoietic Stem Cell Transplant Recipients: A Multicenter Case-Control Study in a High-Prevalence Area

BACKGROUND

Over the last decade, an alarming increase of multidrug-resistant Gram negative (MDR-GN) pathogens has been recorded at hematopoietic stem cell transplant (HSCT) centers, around the world. Infections caused by MDR-GN bacteria not only lead to treatment failure and longer hospital stays but also result in high morbidity and mortality rates.

OBJECTIVE

To examine the incidence, risk factors, and outcomes of MDR-GN bacteremia among (HSCT) recipients, in an area of high antimicrobial resistance.

STUDY DESIGN

Patients with bacteremia, from seven Greek HSCT centers were prospectively enrolled and followed up for 12 months. We compared patients with MDR-GN bacteremia to those with non-MDR-GN bacteremia, Gram-positive (GP) bacteremia and matched controls without bacteremia, in terms of demographics, clinical features, microbiology, and outcomes.

RESULTS

In a total of 523 HSCTs performed, we identified 142 episodes of bacteremia due to MDR-GN (38 patients), non-MDR-GN (37 patients), and GP pathogens (67 patients). The overall incidence of MDR-GN bacteremia was 1.4 / per 1000 patient-days (95% CI 1.0-1.9), ranging from 0.0-2.9/1000 patient-days across participating centers (P=0.01). When comparing patients with MDR-GN bacteremia to those with bacteremia caused by other organisms, in multivariate analysis, age and allogeneic HSCT were independent risk factors for MDR-GN bacteremia. The 12-month mortality rates were 34.5% in bacteremic patients, 60.5% for patients with MDR-GN, 32.4% with non-MDR-GN, and 20.9% with GP bacteremia (p<0.001). MDR-GN bacteremia, relapse of the underlying disease and GvHD were independent risk factors for death.

CONCLUSIONS

These findings highlight the importance of implementing rigorous infection control measures, in HSCT centers located in areas with high prevalence of antimicrobial resistance.

A Population-Based Study of Infectious Diseases Mortality Risk in Patients With Hematologic Malignancies 2000-2020

BACKGROUND

Patients with hematologic malignancies are at high risk of dying from infectious diseases. However, little attention has been paid to infectious diseases mortality (IDM) in these patients. The aim of our study is to determine the incidence and trends of IDM in patients with hematologic malignancies, identify risk factors associated with IDM, and compare the risk of IDM in patients with the general United States population.

METHODS

The data of patients with hematologic malignancies between 2000 and 2020 was retrieved from the Surveillance, Epidemiology, and End Results program. Standardized mortality ratios (SMRs) and IDM rates were calculated. A competing risk model was performed to identify potential risk factors of IDM.

RESULTS

Among 700,678 patients, 15,028 IDM were identified with an IDM rate of 401.31/100,000 person-years. Compared with the general population, the SMR of IDM was 3.34, and the elevated risk of IDM ran through the follow-up period. For all cancer subtypes, the IDM rates were highest in the first 2 months after diagnosis and gradually declined thereafter. For all patients, the early period of diagnosis, older age, male, non-Hispanic black, single or divorced/separated/widowed status, no chemotherapy, and no radiation were risk factors for IDM. For patients with Hodgkin lymphoma or non-Hodgkin lymphoma, advanced stage was also a risk factor for IDM.

CONCLUSION

Given the high risk of IDM in patients with hematologic malignancies, it is extremely important to identify patients at high risk of IDM and provide timely intervention to prevent early death from infections and improve prognosis.

Association between inappropriate empirical antimicrobial therapy and mortality in gram-negative bloodstream infections in patients with febrile neutropenia and hematological malignancy

BACKGROUND AND OBJECTIVE

Inappropriate initial antimicrobial therapy has been associated with high mortality in patients with gram-negative bacilli bloodstream infections during febrile neutropenia following chemotherapy for hematological malignancies. The aim of this study is to determine this association in our hospital.

METHODS

A single center, retrospective, cohort study of bloodstream infection due to gram-negative bacilli and febrile neutropenia was conducted. Clinical characteristics, microbiological etiology, antimicrobial resistance profile, empirical and targeted antibiotic therapy, intensive care unit admission, persistent bacteremia and mortality were analyzed.

RESULTS

Of the 171 episodes of bloodstream infection due to gram-negative bacilli, empirical antimicrobial therapy was inappropriate in 43 episodes (25.1 %). There was a significant difference in mortality at 7 and 30 days between patients who received appropriate versus inappropriate empirical treatment (4.6 % versus 13.9 %, p = 0.04; 15.6 % versus 32.5 %, p = 0.016). Inappropriate empirical treatment (RR, 2.97 [95 % CI, 1.01-8.74]), shock at the time of febrile neutropenia diagnosis (RR, 6.5 [95 % CI, 1.83-23.05]) carbapenem-resistant microorganism (RR, 3.73 [95 % CI, 1.14-12.24]) and persistent bacteremia (RR, 84.6 [95 % CI, 11.3-629.4]) were associated with an increased mortality at 7 and 30 days. In the multivariate analysis, shock (RR, 4.85 [95 % CI, 2.10-11.65]) was independently associated with increased 30-day mortality, but inappropriate empirical antimicrobial therapy was not an independent prognostic determinant (RR, 1.66 [0.53-4.82]).

CONCLUSION

Shock at the time of febrile neutropenia diagnosis contributes to mortality in patients with gram-negative bacilli bloodstream infection, in this scenario, appropriate empirical antimicrobial therapy should be encouraged.

Development and Validation of a Machine Learning Model for the Prediction of Bloodstream Infections in Patients with Hematological Malignancies and Febrile Neutropenia

Background/Objectives: The rise of multidrug-resistant (MDR) infections demands personalized antibiotic strategies for febrile neutropenia (FN) in hematological malignancies. This study investigates machine learning (ML) for identifying patient profiles with increased susceptibility to bloodstream infections (BSI) during FN onset, aiming to tailor treatment approaches. Methods: From January 2020 to June 2022, we used the unsupervised ML algorithm KAMILA to analyze data from hospitalized hematological malignancy patients. Eleven features categorized clinical phenotypes and determined BSI and multidrug-resistant Gram-negative bacilli (MDR-GNB) prevalences at FN onset. Model performance was evaluated with a validation cohort from July 2022 to March 2023. Results: Among 462 FN episodes analyzed in the development cohort, 116 (25.1%) had BSIs. KAMILA's stratification identified three risk clusters: Cluster 1 (low risk), Cluster 2 (intermediate risk), and Cluster 3 (high risk). Cluster 2 (28.4% of episodes) and Cluster 3 (43.7%) exhibited higher BSI rates of 26.7% and 37.6% and GNB BSI rates of 13.4% and 19.3%, respectively. Cluster 3 had a higher incidence of MDR-GNB BSIs, accounting for 75% of all MDR-GNB BSIs. Cluster 1 (27.9% of episodes) showed a lower BSI risk (<1%) with no GNB infections. Validation cohort results were similar: Cluster 3 had a BSI rate of 38.1%, including 78% of all MDR-GNB BSIs, while Cluster 1 had no GNB-related BSIs. Conclusions: Unsupervised ML-based risk stratification enhances evidence-driven decision-making for empiric antibiotic therapies at FN onset, crucial in an era of rising multi-drug resistance.

Etiology, Risk Factors, and Outcomes of Bacteremia in Patients With Hematologic Malignancies and Febrile Neutropenia in Uganda

Background

We determined the etiology, risk factors, and outcomes associated with bacteremia in patients with hematologic malignancies and febrile neutropenia (FN) at the Uganda Cancer Institute (UCI).

Methods

UCI adult and pediatric inpatients with hematologic malignancies and FN were prospectively enrolled and followed up to determine 30-day mortality. Blood drawn from participants with FN was cultured in the BACTEC 9120 blood culture system. Antimicrobial susceptibility testing was performed with the disk diffusion method on identified bacteria. Logistic regression and Cox proportional hazards regression were applied to estimate associations between participant characteristics and FN, bacteremia, and mortality.

Results

Of 495 participants, the majority (n = 306 [62%]) were male. Median age was 23 years (interquartile range, 11-42 years). Of the 132 participants who experienced FN, 43 (33%) had bacteremia. Participants with younger age (odds ratio [OR], 0.98; P = .05), severe neutropenia (OR, 2.9; P = .01), hypotension (OR, 2.46; P = .04), mucositis (OR, 2.77; P = .01), and receipt of chemotherapy (OR, 2.25; P = .03) were more likely to have bacteremia. Fifty (78%) bacteria isolated were gram negative. Escherichia coli (n = 25 [50%]) was predominant. Thirty-seven of 43 (86%) episodes were caused by multidrug-resistant (MDR) bacteria. Thirty-day overall survival for participants with bacteremia was significantly lower than that for participants with no bacteremia (P = .05). MDR bacteremia (hazard ratio, 1.84; P = .05) was associated with increased risk of death.

Conclusions

Bacteremia was frequent in patients with hematologic cancer and FN and was associated with poor survival. MDR bacteria were the main cause of bacteremia and mortality. There is a need for robust infection control and antimicrobial stewardship programs in cancer centers in sub-Saharan Africa.

Genomic evidence of Escherichia coli gut population diversity translocation in leukemia patients

Escherichia coli, a commensal species of the human gut, is an opportunistic pathogen that can reach extra-intestinal compartments, including the bloodstream and the bladder, among others. In non-immunosuppressed patients, purifying or neutral evolution of E. coli populations has been reported in the gut. Conversely, it has been suggested that when migrating to extra-intestinal compartments, E. coli genomes undergo diversifying selection as supported by strong evidence for adaptation. The level of genomic polymorphism and the size of the populations translocating from gut to extra-intestinal compartments is largely unknown. To gain insights into the pathophysiology of these translocations, we investigated the level of polymorphism and the evolutionary forces acting on the genomes of 77 E. coli isolated from various compartments in three immunosuppressed patients. Each patient had a unique strain, which was a mutator in one case. In all instances, we observed that translocation encompasses much of the genomic diversity present in the gut. The same signature of selection, whether purifying or diversifying, and as anticipated, neutral for mutator isolates, was observed in both the gut and bloodstream. Additionally, we found a limited number of non-specific mutations among compartments for non-mutator isolates. In all cases, urine isolates were dominated by neutral selection. These findings indicate that substantial proportions of populations are undergoing translocation and that they present a complex compartment-specific pattern of selection at the patient level.IMPORTANCEIt has been suggested that intra and extra-intestinal compartments differentially constrain the evolution of E. coli strains. Whether host particular conditions, such as immunosuppression, could affect the strain evolutionary trajectories remains understudied. We found that, in immunosuppressed patients, large fractions of E. coli gut populations are translocating with variable modifications of the signature of selection for commensal and pathogenic isolates according to the compartment and/or the patient. Such multiple site sampling should be performed in large cohorts of patients to gain a better understanding of E. coli extra-intestinal diseases.

Risk factors and mortality of carbapenem-resistant Pseudomonas aeruginosa bloodstream infection in haematology department: A 10-year retrospective study

OBJECTIVES

This study aims to investigate the risk factors for carbapenem-resistant Pseudomonas aeruginosa bloodstream infection (CRPA-BSI) and identify predictors of outcomes among patients with P. aeruginosa bloodstream infection (PA-BSI).

METHODS

A retrospective cohort study was conducted on patients with PA-BSI at Henan Cancer Hospital from 2013 to 2022.

RESULTS

Among the 503 incidences analysed, 15.1% of them were CRPA strains. Age, ANC < 100/mmc, receiving antifungal prophylaxis, exposure to carbapenems within the previous 90 days to onset of BSI, and allogeneic HSCT (allo-HSCT) were associated with the development of CRPA-BSI. CRPA-BSI patients experienced significantly higher 28-day mortality rates compared to those with carbapenem-susceptible P. aeruginosa bloodstream infection. Multivariate logistic regression analysis identified age at BSI, active stage of haematological disease, procalcitonin levels, prior corticosteroid treatment, isolation of CRPA, and septic shock as independent predictors of 28-day mortality.

CONCLUSIONS

Risk factors for CRPA-BSI include age, ANC < 100/mmc, antifungal prophylaxis, exposure to carbapenems, and allo-HSCT. Additionally, age at BSI, active haematological disease, procalcitonin levels, prior corticosteroid treatment, CRPA isolation, and septic shock contribute to increased mortality rates among patients with PA-BSI.

Clinical Predictors of Bacteremia Outcome After Initial Empirical Antimicrobial Therapy in Patients with Hematological Malignancies: A Retrospective Analysis

Objective

We performed a retrospective analysis to investigate the clinical predictors of bacteremia outcome involving Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) after initial empirical antimicrobial therapy among hematological malignancy cases.

Methods

This retrospective study was conducted between April 2018 and April 2023. All bloodstream infections (BSIs) caused by E. coli and K. pneumoniae in hospitalized hematological malignancy (HM) patients were identified. Data on patient demographics, clinical characteristics, empirical antimicrobial treatment, outcomes and the antimicrobial susceptibility were collected from medical records. Multivariate analyses were utilized to assess the risk factors for all-cause mortality within 28 days and carbapenem resistance. Optimal cutoffs for continuous predictive variables were evaluated by receiver operating characteristic (ROC) curve analysis.

Results

Among 61 individuals diagnosed with bacteremia, 39 cases were caused by E. coli bacteremia, while the remaining 22 were identified as K. pneumoniae bacteremia. Out of these, there were 10 cases of carbapenem-resistant Enterobacteriaceae (CRE) and 12 cases resulted in all-cause mortality within 28 days. Analysis indicated that Pitt score was an independent risk factor for mortality and a cut-off of 2.5 was a reliable predictor with 83.3% sensitivity and 85.7% specificity, respectively. Impaired mental status and elevated body temperature exceeding 38.6°C as well as a procalcitonin (PCT) level over 8.24 ng/mL on the third day (d3) after antimicrobial treatment were identified as independent risk factors for predicting carbapenem resistance.

Conclusion

We found that Pitt score with a cut-off of 2.5 was a reliable predictor for mortality within 28 days in HM bacteremia cases. Impaired mental status and elevated temperature exceeding 38.6°C as well as a procalcitonin (PCT) level over 8.24 ng/mL on d3 after antimicrobial treatment were identified as predictive risk factors to carbapenem resistance.

Bloodstream infections in neutropenic and non-neutropenic patients with haematological malignancies: epidemiological trends and clinical outcomes in Queensland, Australia over the last 20 years

Knowledge of the epidemiology of bloodstream infection (BSI) in haematology patients is essential to guide patient management. We investigated the epidemiology of BSI in patients with haematological malignancies in Queensland over the last 20 years (2000-2019), including all episodes diagnosed by the state-wide microbiology service. We identified 7749 BSI in 5159 patients, 58% associated with neutropenia. Gram-negatives were the main causative pathogens (58.3%), more frequent in neutropenic than non-neutropenic patients (3308/5309, 62.3% vs 1932/3678, 52.5%, p < 0.001). Amongst 8987 isolates the most common were E. coli (15.4%) and Pseudomonas spp. (14.2%). Pseudomonas spp. (16.6% vs 10.7%, p < 0.001), Klebsiella spp. (11.6% vs 6.8%, p < 0.001), viridans-group streptococci (4.4% vs 1.2%, p < 0.001) and E. faecium (2.4% vs 0.9%, p < 0.001) were more common in neutropenic than non-neutropenic patients, while S. aureus was less common (5.9% vs 15.6%, p < 0.001). Several antimicrobial resistance rates increased over time and had higher prevalence in neutropenic than non-neutropenic patients, including ciprofloxacin-resistant E. coli (94/758, 12.4% vs 42/506, 8.3%, p = 0.021), trimethoprim-sulfamethoxazole-resistant E. coli (366/764, 47.9% vs 191/517, 36.9%, p < 0.001), penicillin-resistant streptococci (51/236, 21.6% vs 28/260, 10.8%, p < 0.001) and vancomycin-resistant enterococci (46/250, 18.4% vs 9/144, 6.3%, p < 0.001). Carbapenem-resistant Pseudomonas spp. (OR 7.32, 95%CI 2.78-19.32) and fungi, including yeasts and moulds (OR 3.33, 95%CI 2.02-5.48) were associated to the highest odds of 30-day case-fatality at a multivariable logistic regression analysis. Neutropenia was associated with survival (OR 0.66, 95%CI 0.55-0.78). Differences were observed in the BSI epidemiology according to neutropenic status, with an overall increase of resistance over time associated to adverse outcome.

Evaluation of antibiotic resistance, toxin-antitoxin systems, virulence factors, biofilm-forming strength and genetic linkage of Escherichia coli strains isolated from bloodstream infections of leukemia patients

BACKGROUND

One of the most common complications in patients with febrile neutropenia, lymphoma, leukemia, and multiple myeloma is a bloodstream infection (BSI).

OBJECTIVE

This study aimed to evaluate the antibiotic resistance patterns, virulence factors, biofilm-forming strength, and genetic linkage of Escherichia coli strains isolated from bloodstream infections (BSIs) of leukemia patients.

METHODS

The study conducted in Iran from June 2021 to December 2022, isolated 67 E. coli strains from leukemia patients' bloodstream infections in hospitals in two different areas. Several techniques including disk diffusion and broth microdilution were used to identify patterns of antibiotic resistance, microtiter plate assay to measure biofilm formation, and PCR to evaluate the prevalence of different genes such as virulence factors, toxin-antitoxin systems, resistance to β-lactams and fluoroquinolone antibiotics of E. coli strains. Additionally, the genetic linkage of the isolates was analyzed using the Enterobacterial Repeat Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) method.

RESULTS

The results showed that higher frequency of BSI caused by E. coli in man than female patients, and patients with acute leukemia had a higher frequency of BSI. Ampicillin and Amoxicillin-clavulanic acid showed the highest resistance, while Imipenem was identified as a suitable antibiotic for treating BSIs by E. coli. Multidrug-resistant (MDR) phenotypes were present in 22% of the isolates, while 53% of the isolates were ESBL-producing with the blaCTX-M gene as the most frequent β-lactamase gene. The fluoroquinolone resistance genes qnrB and qnrS were present in 50% and 28% of the isolates, respectively. More than 80% of the isolates showed the ability to form biofilms. The traT gene was more frequent than other virulence genes. The toxin-antitoxin system genes (mazF, ccdAB, and relB) showed a comparable frequency. The genetic diversity was detected in E. coli isolates.

CONCLUSION

Our results demonstrate that highly diverse, resistant and pathogenic E. coli clones are circulating among leukemia patients in Iranian hospitals. More attention should be paid to the treatment and management of E. coli bloodstream infections in patients with leukemia.

All-Cause Mortality and Its Predictors in Haemato-Oncology Patients with Febrile Neutropenia

Febrile neutropenia (FN) is one of the most important life-threatening complications in haemato-oncology. Our objective was to report all-cause mortality rates in patients ill with a hematological malignancy (HM) hospitalized with a first FN episode and to identify predictors for mortality. We conducted a historical retrospective cohort study of consecutive patients with an HM, >18 years of age, admitted between January 2012 and August 2018 for a first episode of FN. Data on all-cause mortality 12 months after admission for FN were obtained. The Kaplan-Meier curve was used to describe mortality during the follow-up period. Univariate and multivariable analyses identified predictors for 1,3 and 12-month mortality. One hundred and fifty-eight patients (mean age 69.5, 49.4% males) were included. Overall, 54 patients died (15.8%, 25.9%, and 34.1% died after 1, 3, and 12 months, respectively). Lower serum albumin, higher serum gamma-glutamyl transferase (GGT), lower estimated glomerular filtration rate (eGFR), older age, higher temperature, and lower absolute lymphocyte count at admission were independent predictors of all-cause mortality after 12 months. Further studies are needed to confirm our results and identify therapeutic strategies to improve survival.

Molecular and Clinical Data of Antimicrobial Resistance in Microorganisms Producing Bacteremia in a Multicentric Cohort of Patients with Cancer in a Latin American Country

Patients with cancer have a higher risk of severe bacterial infections. This study aims to determine the frequency, susceptibility profiles, and resistance genes of bacterial species involved in bacteremia, as well as risk factors associated with mortality in cancer patients in Colombia. In this prospective multicenter cohort study of adult patients with cancer and bacteremia, susceptibility testing was performed and selected resistance genes were identified. A multivariate regression analysis was carried out for the identification of risk factors for mortality. In 195 patients, 206 microorganisms were isolated. Gram-negative bacteria were more frequently found, in 142 cases (68.9%): 67 Escherichia coli (32.5%), 36 Klebsiella pneumoniae (17.4%), and 21 Pseudomonas aeruginosa (10.1%), and 18 other Gram-negative isolates (8.7%). Staphylococcus aureus represented 12.4% (n = 25). Among the isolates, resistance to at least one antibiotic was identified in 63% of them. Genes coding for extended-spectrum beta-lactamases and carbapenemases, blaCTX-M and blaKPC, respectively, were commonly found. Mortality rate was 25.6% and it was lower in those with adequate empirical antibiotic treatment (22.0% vs. 45.2%, OR: 0.26, 95% CI: 0.1-0.63, in the multivariate model). In Colombia, in patients with cancer and bacteremia, bacteria have a high resistance profile to beta-lactams, with a high incidence of extended-spectrum beta-lactamases and carbapenemases. Adequate empirical treatment diminishes mortality, and empirical selection of treatment in this environment of high resistance is of key importance.

Better Outcome of Off-Label High-Dose Ceftazidime in Hemato-Oncological Patients with Infections Caused by Extensively Drug-Resistant Pseudomonas Aeruginosa

Background

P. aeruginosa sepsis in immunocompromised patients is a serious complication of cancer treatment, especially in the case of an Extensively Drug Resistant (XDR) pathogen. The aim of the study is to evaluate the efficacy of high-dose ceftazidime in the treatment of XDR P. aeruginosa infection and to compare it with the conventionally treated cohort in hemato-oncological patients.

Methods

We identified 27 patients with XDR P. aeruginosa infection during the 2008-2018 period, 16 patients served as a conventionally treated cohort with an antipseudomonal beta-lactam antibiotic in standard dose (cohort A), and 11 patients were treated with high-dose ceftazidime (cohort B). Most of the patients were neutropenic and under active treatment for their cancer in both cohorts.

Results

Mortality and related mortality were statistically significantly better for cohort B than cohort A; it was 18.2% and 9.1% for cohort B and 68.8% and 68.8% for cohort A, respectively. More patients in cohort A needed mechanical ventilation and renal replacement therapy, 75% and 50% for cohort A and 27.3% and 9.9% for cohort B, respectively. It corresponded well with the worst sequential organ failure score (SOFA) in cohort A compared to cohort B, 16 versus 7, respectively. Reversible neurotoxicity was seen only in two patients in cohort B.

Conclusion

Ceftazidime in high doses is a very potent antibiotic (ATB) for treating XDR P. aeruginosa infections in neutropenic cancer with acceptable toxicity.

Factors Associated with Gram-Negative Bacteremia and Mortality in Neutropenic Patients with Hematologic Malignancies in a High-Resistance Setting

Objective

Patients with hematological malignancies (HMs) have a substantial incidence of febrile neutropenic episodes. Gram-negative bacteremia (GNB) is still the major cause of these episodes. We evaluated the factors associated with GNB and mortality of bacteremic patients with HMs in a high-resistance setting.

Materials and Methods

We conducted a prospective cohort study from March 2018 to June 2019 with 66 bacteremic and 132 non-bacteremic patients. Regression analyses were used to identify factors associated with GNB and 30-day mortality.

Results

The mean age was 53.83±15.21 years, and 129 (65.2%) of the patients were male. In multivariable analysis, factors independently associated with GNB were male gender, duration of hospitalization and neutropenia before the febrile neutropenic episode, leukemias and allogeneic transplant recipients, radiotherapy, receiving glucocorticosteroids, colonization with resistant microorganisms. All-cause mortality and 30-day mortality were 47.0% and 30.3% in cases of GNB, compared to non-bacteremic controls 25.0% and 10.6%, respectively. Sepsis, duration of hospitalization before the febrile neutropenic episode, carbapenem-resistant GNB, and inappropriate empirical antibiotic treatment was found as factors associated with 30-day mortality. Prior antibiotic exposure particularly beta-lactamase inhibitor combinations and carbapenems during the past 30 days was more frequent in the bacteremic group. An increasing trend was observed in multidrug-resistant (MDR) bacteria (p=0.03) and carbapenem-resistant Enterobacterales (p=0.02) over the years.

Conclusion

By considering the risk factors associated with GNB and 30-day mortality that we detected in our study among neutropenic patients, a personalized approach for the management of febrile neutropenic patients can be designed by means of an effective antimicrobial stewardship program including the appropriate use of broad-spectrum antibiotics.

Effectiveness of antimicrobial stewardship programmes based on rapid antibiotic susceptibility testing of haematologic patients having high-risk factors for bacteraemia related mortality: A post-hoc analysis of an RCT

OBJECTIVES

A randomised controlled trial showed that rapid phenotypic antibiotic susceptibility testing (AST) with antimicrobial stewardship programmes (ASP) increases the proportion of haematologic patients with bacteraemia receiving optimal targeted therapy within 72 hrs of blood culture collection. The present post-hoc analysis aimed to evaluate the effects of rapid phenotypic AST intervention in haematologic patients at high risk of a poor outcome from bacteraemia.

METHODS

Haematologic patients with bacteraemia (n = 116) were assigned randomly to a conventional AST group or a rapid AST group. The two outcome measures were the proportion of patients receiving optimal targeted therapy at 72 hrs post-blood culture collection and the time to optimal targeted therapy; subgroup analysis was conducted based on baseline demographics (age, sex) and prognostic (Charlson comorbidity index, haematologic treatment intensity, Pitt bacteraemia score, appropriateness of empirical antibiotic therapy and multidrug-resistant organism) indicators. The interaction effect between the intervention and subgroup factors was examined using regression model analysis.

RESULTS

Age, sex, Charlson comorbidity index, haematologic treatment intensity, Pitt bacteraemia score and appropriateness of empirical antibiotic therapy had no significant interaction effects on the proportion of patients receiving optimal targeted therapy (P = 0.129-0.826). However, infection by a multidrug-resistant organism did have a significant interaction effect (P = 0.042). Regarding time to optimal targeted therapy, there were no significant interaction effects between the intervention and subgroup factors (P = 0.156-0.848).

CONCLUSIONS

Rapid phenotypic AST intervention may accelerate early optimal targeted antimicrobial treatment of haematologic patients, even those in high-risk subgroups with bacteraemia.

Risk of infections and mortality in Danish patients with cancer diagnosed with bone metastases: a population-based cohort study

OBJECTIVES

Risk of infections in patients with solid cancers and bone metastases (BM) and the subsequent impact on prognosis is unclear. We examined the risk of infections among patients with cancer diagnosed with BM and the subsequent impact of infections on mortality.

DESIGN

Population-based cohort study.

SETTING

Danish medical databases holding information on all hospital contacts in Denmark.

PARTICIPANTS

Adult patients with solid cancers and BM between 1 January 1994 and 30 November 2013.

OUTCOME MEASURES

In the risk analyses, the outcome was time to hospitalisation for common severe infections, pneumonia, sepsis and urinary tract infections. In the mortality analysis, we used Cox regression to compute HRs of death, modelling infection as time-varying exposure, stratifying for primary cancer type and adjusting for age, sex and comorbidities.

RESULTS

Among 23 336 patients with cancer and BM, cumulative incidences of common severe infections were 4.6%, 14.0% and 20.0% during 1 month, 1 year and 10 years follow-up. The highest incidence was observed for pneumonia, followed by urinary tract infections and sepsis. Infection was a strong predictor of 1 month mortality (adjusted HR: 2.1 (95% CI 1.8 to 2.3)) and HRs increased after 1 and 10 years: 2.4 (95% CI 2.3 to 2.6) and 2.4 (95% CI 2.4 to 2.6). Sepsis and pneumonia were the strongest predictors of death. Results were consistent across cancer types.

CONCLUSION

Patients with cancer and BM were at high risk of infections, which was associated with a more than twofold increased risk of death for up to 10 years of follow-up. The findings underscore the importance of preventing infections in patients with cancer and BM.

The Impact of Bacterial Biofilms on End-Organ Disease and Mortality in Patients with Hematologic Malignancies Developing a Bloodstream Infection

Bacterial bloodstream infection (BSI) represents a significant complication in hematologic patients. However, factors leading to BSI and progression to end-organ disease and death are understood only partially. The study analyzes host and microbial risk factors and assesses their impact on BSI development and mortality. A total of 96 patients with hematological malignancies and BSI were included in the study. Host-associated risk factors and all causes of mortality were analyzed by multivariable logistic regression at 30 days after BSI onset of the first neutropenic episode. The multidrug-resistant profile and biofilm production of bacterial isolates from primary BSI were included in the analysis. Median age was 60 years. The underlying diagnoses were acute leukemia (55%), lymphoma (31%), and myeloma (14%). A total of 96 bacterial isolates were isolated from BSIs. Escherichia coli was the most common isolate (29.2%). Multidrug-resistant bacteria caused 10.4% of bacteremia episodes. Weak biofilm producers (WBPs) were significantly (P < 0.0001) more abundant (72.2%) than strong biofilm producers (SBPs) (27.8%). Specifically, SBPs were 7.1% for E. coli, 93.7% for P. aeruginosa, 50% for K. pneumoniae, and 3.8% for coagulase-negative staphylococci. Mortality at day 30 was 8.3%, and all deaths were attributable to Gram-negative bacteria. About 22% of all BSIs were catheter-related BSIs (CRBSIs) and mostly caused by Gram-positive bacteria (79.0%). However, CRBSIs were not correlated with biofilm production levels (P = 0.75) and did not significantly impact the mortality rate (P = 0.62). Conversely, SBP bacteria were an independent risk factor (P = 0.018) for developing an end-organ disease. In addition, multivariate analysis indicated that SBPs (P = 0.013) and multidrug-resistant bacteria (P = 0.006) were independent risk factors associated with 30-day mortality. SBP and multidrug-resistant (MDR) bacteria caused a limited fraction of BSI in these patients. However, when present, SBPs raise the risk of end-organ disease and, together with an MDR phenotype, can independently and significantly concur at increasing the risk of death. IMPORTANCE Bacterial bloodstream infection (BSI) is a significant complication in hematologic patients and is associated with high mortality rates. Despite improvements in BSI management, factors leading to sepsis are understood only partially. This study analyzes the contribution of bacterial biofilm on BSI development and mortality in patients with hematological malignancies (HMs). In this work, weak biofilm producers (WBPs) were significantly more abundant than strong biofilm producers (SBPs). However, when present, SBP bacteria raised the risk of end-organ disease in HM patients developing a BSI. Besides, SBPs, together with a multidrug-resistant (MDR) phenotype, independently and significantly concur at increasing the risk of death in HM patients. The characterization of microbial biofilms may provide key information for the diagnosis and therapeutic management of BSI and may help develop novel strategies to either eradicate or control harmful microbial biofilms.

Healthcare-associated blood stream infections in hematological patients in Finland during the years 2006-2016

OBJECTIVES

The aim was to identify the clinical characteristics, outcome, and antimicrobial susceptibility of healthcare-associated bloodstream infections (BSIs) in hematological patients.

METHODS

This retrospectively collected laboratory-based surveillance data include 3404 healthcare-associated BSIs in 2296 patients with a hematological malignancy in hospitals participating in the Finnish Hospital Infection Program from January 1, 2006, to December 31, 2016.

RESULTS

The most common underlying diseases were acute myelogenous leukemia (35%) and non-Hodgkin lymphoma (22%). Gram-positive organisms accounted for 60%-46% and gram-negative organisms for 24%-36% of BSIs in 2006-2016. The most common causative organism was coagulase-negative staphylococci (CoNS) (n = 731). The 7- and 28-day case fatality rates were 5.2% and 11.4%, respectively, and was highest in BSIs caused by Candida species (10.8% and 30.8%). The median age of patients increased from 59 years in 2006-2008 to 62 years in 2015-2016 (P < .01). Five percent of S aureus isolates were resistant to methicillin and five percent of Pseudomonas aeruginosa isolates were multidrug-resistant. Four percent of Klebsiella and seven percent of E coli isolates were resistant to ceftazidime.

CONCLUSIONS

The proportion of gram-positive bacteria decreased and gram-negative bacteria increased over time. The case fatality rate was low and the median age of patients increased during the study.

Bacteremia in critically ill immunocompromised patients with acute hypoxic respiratory failure: A post-hoc analysis of a prospective multicenter multinational cohort

PURPOSE

The characteristics and impact of bacteremia have not been widely investigated in immunocompromised patients with acute respiratory failure (ARF).

METHODS

We performed a secondary analysis of a prospective cohort of immunocompromised patients with ARF (EFRAIM study). After exclusion of blood cultures positive for coagulase negative Staphylococci, we compared patients with (n = 236) and without (n = 1127) bacteremia.

RESULTS

The incidence of bacteremia was 17%. Bacterial pneumonia and extra-pulmonary ARDS were the main causes of ARF in bacteremic patients. Bacteremia involved gram negative rods (48%), gram positive cocci (40%) or were polymicrobial (10%). Bacteremic patients had more hematological malignancy, higher SOFA scores and increased organ support within 7 days. Bacteremia was associated with higher crude ICU mortality (40% versus 32%, p = 0.02), but neither hospital (49% versus 44%, p = 0.17) nor 90-day mortality (60% versus 56%, p = 0.25) were different from non-bacteremic patients. After propensity score matching based on baseline characteristics, the difference in ICU mortality lost statistical significance (p = 0.06), including in a sensitivity analysis restricted to patients with pneumonia.

CONCLUSIONS

We analyzed a large population of immunocompromised patients with ARF and an incidence of bacteremia of 17%. We could not demonstrate an impact of bacteremia on mortality after adjusting for baseline characteristics.

D-index as a marker of bloodstream infections in patients with allogeneic hematopoietic stem cell transplantation

BACKGROUND

Neutropenia is a risk factor for development of infections; however, the direct effect of neutropenia on development of bloodstream infection (BSI) is not known. D-index, which is area between the neutrophil time curve and a neutrophil count of 0.5 × 10⁹ /L, incorporates the combined effect of severity and duration of neutropenia. We aimed to evaluate whether D-index can be used as a marker for BSI in patients with allogeneic stem cell transplantation.

METHOD

We conducted a retrospective cohort study of patients undergoing allogeneic stem cell transplantation between January 1, 2005, and September 30, 2015. The primary outcome measure was the development of BSI within 30 days of transplantation.

RESULTS

A total of 714 patients were included in the study of whom 101 developed BSI. Patients with BSI had a significantly higher median D-index value compared with patients who did not have BSI (4990 vs. 3570, P < .001). As a marker, the performance of the D-index was similar to that of the duration of profound neutropenia (P = .18) and significantly better than the total duration of neutropenia (P = .001).

CONCLUSION

The D-index performed better than the total duration of neutropenia as a marker for BSI in patients with allogeneic stem cell transplantation. There was no difference between D-index and, a more easily calculable indicator, duration of profound neutropenia.

Fluoroquinolone treatment as a protective factor for 10-day mortality in Streptococcus pneumoniae bacteremia in cancer patients

To evaluate the prognostic factors in adult cancer patients with pneumococcal bacteremia, describe episode features and the phenotypic characteristics of the isolated strains. We evaluated the episodes in patients admitted to a cancer hospital between 2009 and 2015. The outcomes were defined as 48 h mortality and mortality within 10 days after the episode. The variables evaluated were: age, sex, ethnicity, ECOG, Karnofsky score, SOFA, cancer type, metastasis, chemotherapy, radiotherapy, neutropenia, previous antibiotic therapy, community or healthcare-acquired infection, comorbidities, smoking, pneumococcal vaccination, infection site, presence of fever, polymicrobial infection, antimicrobial susceptibility, serotype and treatment. 165 episodes were detected in 161 patients. The mean age was 61.3 years; solid tumors were the most prevalent (75%). 48 h and 10-day mortality were 21% (34/161) and 43% (70/161) respectively. The 48 h mortality- associated risk factors were SOFA and polymicrobial bacteremia; 10-day mortality-associated risk factors were fever, neutropenia, ECOG 3/4, SOFA and fluoroquinolones as a protective factor. Pneumococcal bacteremia presented high mortality in cancer patients, with prognosis related to intrinsic host factors and infection episodes features. Fluoroquinolone treatment, a protective factor in 10-day mortality, has potential use for IPDs and severe community-acquired pneumonia in cancer patients.

Association of Acute Kidney Injury With Subsequent Sepsis in Critically Ill Children

OBJECTIVES

Acute kidney injury is a major cause of morbidity and mortality in critically ill children. A growing body of evidence has shown that acute kidney injury affects immune function, yet little is known about the association between acute kidney injury and subsequent infection in pediatric patients. Our objective was to examine the association of non-septic acute kidney injury with the development of subsequent sepsis in critically ill children.

DESIGN

A single-center retrospective cohort study.

SETTING

The pediatric and cardiac ICUs at a tertiary pediatric care center.

PATIENTS

All patients 0-18 years old without a history of chronic kidney disease, who did not have sepsis prior to or within the initial 48 hours of ICU admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We analyzed data for 5,538 children (median age, 5.3 yr; 58.2% male), and identified 255 (4.6%) with stage 2 or 3 acute kidney injury. Suspected sepsis occurred in 46 children (18%) with stage 2 or 3 acute kidney injury compared to 286 children (5.4%) with stage 1 or no acute kidney injury. On adjusted analysis, children with stage 2 or 3 acute kidney injury had 2.05 times greater odds of developing sepsis compared to those with stage 1 or no acute kidney injury (95% CI, 1.39-3.03; p < 0.001). Looking at acute kidney injury severity, children with stage 2 and 3 acute kidney injury had a 1.79-fold (95% CI, 1.15-2.79; p = 0.01) and 3.24-fold (95% CI, 1.55-6.80; p = 0.002) increased odds of developing suspected sepsis, respectively.

CONCLUSIONS

Acute kidney injury is associated with an increased risk for subsequent infection in critically ill children. These results further support the concept of acute kidney injury as a clinically relevant immunocompromised state.

Epidemiology, Risk Factors, and Clinical Outcomes of Bloodstream Infection due to Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae in Hematologic Malignancy: A Retrospective Study from Central South China

Objective: To determine the epidemiology, risk factors, and prognosis of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae bloodstream infections (BSIs) among hematology malignancy (HM) patients in China. Method: From January 2010 to June 2018, we retrospectively collected and analyzed the 449 HM patients with E. coli or K. pneumoniae BSIs from three leading hospitals in Hunan Province, China. Results: Two hundred four (45.4%) patients harbored ESBL-producing bacteremia. The proportion of ESBL-producing bacteremia increased significantly with the growth of the year, with a ratio of 34.47% in 2010-2014 to 54.7% in 2015-2018. Comparing with non-ESBL groups in HM patients, central venous catheter (odds ratio [OR] 1.717, p = 0.009), previous antibiotic exposure (OR 1.559, p = 0.035), and E. coli (OR 2.561, p ≤ 0.001) among ESBL groups were independent risk factors. No significant differences in 30-day mortality were tested in patients with BSI caused by ESBL-producing or non-ESBL-producing E. coli and K. pneumoniae (17.1% vs. 16.7%; p = 0. 893). The proportion of carbapenem used within 72 hours after the onset of bacteremia in two groups was high, which was routinely used as "last-resort drugs" in Gram-negative bacterial infections. Risk factors associated with 30-day mortality in HM patients with E. coli or K. pneumoniae bacteremia were myelodysplastic syndrome, incomplete remission of the disease, Multinational Association of Supportive Care in Cancer score <21, Pitt bacteremia score ≥4, Charlson comorbidity score >3, catheter insertion, use of vasopressors, and inappropriate antibiotics within 72 hours of BSI onset. Conclusions: The results of this study may provide some references for the whole process management of HM patients with BSIs.

Clinical Characteristics and Risk Factors for Bloodstream Infection Due to Carbapenem-Resistant Klebsiella pneumoniae in Patients with Hematologic Malignancies

Purpose

The aim was to examine the clinical characteristics and risk factors for bloodstream infection (BSI) due to carbapenem-resistant Klebsiella pneumoniae (CRKP) in patients with hematologic malignancies.

Materials and Methods

A single-centre, retrospective case–control study representing 734 patients with hematologic malignancies between January 1, 2017, and December 31, 2018, was conducted. Demographic and clinical data were collected from the hospital electronic medical records system.

Results

Among the 734 patients with hematologic malignancies, 3% (22/734) of the patients developed CRKP BSI during their hospitalization. Overall 28-day all-cause mortality reached 77.3% (17/22). Patients with Pitt bacteremia score (PBS) >4, pneumonia and septic shock were more frequent in the non-survivors versus the survivors. Compared with the non-survivors in antimicrobial treatment, combination therapy of tigecycline and polymyxin B was more common in the survivors. The independent risk factors associated with CRKP BSI were CRKP rectal colonization (OR, 11.067; CI=4.43–27.644; P<0.001; 3 points), severe neutropenia (OR, 4.095; CI=0.876–19.141; P=0.073; 1 point) and invasive mechanical ventilation (IMV) within the previous 30 days to onset of BSI (OR, 18.444; CI=1.787–190.343; P=0.014; 4 points). The total risk score of ≥5 indicated that the probability of CRKP BSI occurrence was above 48%.

Conclusion

CRKP BSI in patients with hematologic malignancies is associated with high mortality. The risk factor-based prediction model might help clinicians to start prompt effective anti-infective therapy in patients with suspicion of CRKP BSI and improve outcomes.

Risk factors for and clinical outcomes of carbapenem non-susceptible gram negative bacilli bacteremia in patients with acute myelogenous leukemia

BACKGROUND

Carbapenem is frequently used when gram negative bacilli (GNB) bacteremia is detected especially in neutropenic patients. Consequently, appropriate treatment could be delayed in GNB bacteremia cases involving organisms which are not susceptible to carbapenem (carba-NS), resulting in a poor clinical outcomes. Here, we explored risk factors for carba-NS GNB bacteremia and its clinical outcomes in patients with acute myelogenous leukemia (AML) that underwent chemotherapy.

METHODS

We reviewed all GNB bacteremia cases that occurred during induction or consolidation chemotherapy, over a 15-year period, in a tertiary-care hospital.

RESULTS

Among 489 GNB bacteremia cases from 324 patients, 45 (9.2%) were carba-NS and 444 (90.8%) were carbapenem susceptible GNB. Independent risk factors for carba-NS GNB bacteremia were: carbapenem use at bacteremia onset (adjusted odds ratio [aOR]: 91.2; 95% confidence interval [95%CI]: 29.3-284.1; P < 0.001); isolation of carbapenem-resistant Acinetobacter baumannii (aOR: 19.4, 95%CI: 3.4-112.5; P = 0.001) in the prior year; and days from chemotherapy to GNB bacteremia (aOR: 1.1 per day, 95%CI: 1.1-1.2; P < 0.001). Carba-NS bacteremia was independently associated with in-hospital mortality (aOR: 6.6, 95%CI: 3.0-14.8; P < 0.001).

CONSLUSION

Carba-NS organisms should be considered for antibiotic selection in AML patients having these risk factors.

Ceftazidime/Avibactam and Ceftolozane/Tazobactam for Multidrug-Resistant Gram Negatives in Patients with Hematological Malignancies: Current Experiences

Patients suffering from hematological malignancies are at high risk for severe infections, including in particular bloodstream infections, which represent one of the most frequent life-threatening complications for these patients, with reported mortality rates reaching 40%. Furthermore, a worrisome increase in antimicrobial resistance of Gram-negative bacteria (e.g., cephalosporin- and/or carbapenem-resistant Enterobacteriaceae and multidrug-resistant (MDR) Pseudomonas aeruginosa) involved in severe infectious complications among patients with hematological malignancies has been reported during the last years. The two novel combination of cephalosporins and β-lactamase inhibitors, ceftolozane/tazobactam and ceftazidime/avibactam, were recently approved for treatment of complicated intra-abdominal and urinary tract infections and nosocomial pneumonia and display activity against several MDR Gram-negative strains. Although not specifically approved for neutropenic and/or cancer patients, these drugs are used in this setting due to increasing rates of infections caused by MDR Gram-negative bacteria. The aim of this review is to describe the actual evidence from scientific literature about the "real-life" use of these two novel drugs in patients with hematological malignancies and infections caused by MDR Gram-negative bacteria.

Contribution of specific pathogens to bloodstream infection mortality in neutropenic patients with hematologic malignancies: Results from a multicentric surveillance cohort study

Bloodstream infection (BSI) remains a serious complication in patients with hematologic malignancies and neutropenia. The risk factors for mortality after BSI and the contributions of BSI pathogens to mortality remain incompletely understood. We evaluated first BSI among adult neutropenic patients undergoing high-dose chemotherapy for hematologic malignancies in the setting of (a) an early disease stage of autologous (auto-HSCT) or allogeneic (allo-HSCT) hematopoietic stem cell transplantation or (b) for acute leukemia. Risk factors for intensive care admission and all-cause mortality were analyzed by multivariable logistic regression 7 and 30 days after onset of the first BSI in the first neutropenic episode. Between 2002 and 2015, 9080 patients met the study inclusion criteria, and 1424 (16%) developed BSIs, most of them during the first week of neutropenia. Mortality during neutropenia within 7 days and 30 days after BSI onset was 2.5% and 5.1%, respectively, and differed considerably between BSI pathogens. Both 7-day and 30-day mortalities were highest for Pseudomonas aeruginosa BSI (16.7% and 26.7%, respectively) and lowest for BSI due to coagulase-negative Staphylococcus spp. (CoNS) and Streptococcus spp. BSI pathogens were independently associated with 7-day mortality included P aeruginosa, Klebsiella spp., Enterobacter spp., Serratia spp., and enterococci. Only gram-negative BSI and candidemia were associated with admission to intensive care within 7 days after BSI onset. BSI caused by P aeruginosa continues to carry a particularly poor prognosis in neutropenic patients. The unexpected association between enterococcal BSI and increased mortality needs further study.

Bloodstream infections caused by Escherichia coli in onco-haematological patients: Risk factors and mortality in an Italian prospective survey

Bloodstream infections (BSIs) remain life-threatening complications in the clinical course of patients with haematological malignancies (HM) and Escherichia coli represent one of the most frequent cause of such infections. In this study, we aimed to describe risk factors for resistance to third generation cephalosporins and prognostic factors, including the impact of third generation cephalosporins resistance, in patients with HM and BSIs caused by E. coli. Three hundred forty-two cases of E. coli BSIs were collected during the study period (from January 2016 to December 2017). The percentage of resistance to third generation cephalosporins was 25.7%. In multivariate analysis, the variables recent endoscopic procedures, culture-positive surveillance rectal swabs for multidrug-resistant bacteria, antibiotic prophylaxis with fluoroquinolones, and prolonged neutropenia were independently associated with bloodstream infections caused by a third generation cephalosporins resistant E. coli. The overall 30-day mortality rate was 7.1%. Cox regression revealed that significant predictors of mortality were acute hepatic failure, septic shock, male sex, refractory/relapsed HM, and third generation cephalosporins resistance by E. coli isolate. In conclusion, resistance to third generation cephalosporins adversely affected the outcomes of bloodstream infections caused by E. coli in our cohort of HM patients. We also found a significant correlation between prophylaxis with fluoroquinolones and resistance to third generation cephalosporins by E. coli isolates.

Predictors of multidrug-resistant Pseudomonas aeruginosa in neutropenic patients with bloodstream infection

OBJECTIVES

To assess risk factors for multidrug-resistant Pseudomonas aeruginosa (MDR-PA) infection in neutropenic patients.

METHODS

Single-centre retrospective analysis of consecutive bloodstream infection (BSI) episodes (2004-2017, Barcelona). Two multivariate regression models were used at BSI diagnosis and P. aeruginosa detection. Significant predictors were used to establish rules for stratifying patients according to MDR-PA BSI risk.

RESULTS

Of 661 Gram-negative BSI episodes, 190 (28.7%) were caused by P. aeruginosa (70 MDR-PA). Independent factors associated with MDR-PA among Gram-negative organisms were haematological malignancy (OR 3.30; 95% CI 1.15-9.50), pulmonary source of infection (OR 7.85; 95% CI 3.32-18.56), nosocomial-acquired BSI (OR 3.52; 95% CI 1.74-7.09), previous antipseudomonal cephalosporin (OR 13.66; 95% CI 6.64-28.10) and piperacillin/tazobactam (OR 2.42; 95% CI 1.04-5.63), and BSI occurring during ceftriaxone (OR 4.27; 95% CI 1.15-15.83). Once P. aeruginosa was identified as the BSI aetiological pathogen, nosocomial acquisition (OR 7.13; 95% CI 2.87-17.67), haematological malignancy (OR 3.44; 95% CI 1.07-10.98), previous antipseudomonal cephalosporin (OR 3.82; 95% CI 1.42-10.22) and quinolones (OR 3.97; 95% CI 1.37-11.48), corticosteroids (OR 2.92; 95% CI 1.15-7.40), and BSI occurring during quinolone (OR 4.88; 95% CI 1.58-15.05) and β-lactam other than ertapenem (OR 4.51; 95% CI 1.45-14.04) were independently associated with MDR-PA. Per regression coefficients, 1 point was assigned to each parameter, except for nosocomial-acquired BSI (3 points). In the second analysis, a score >3 points identified 60 (86.3%) out of 70 individuals with MDR-PA BSI and discarded 100 (84.2%) out of 120 with non-MDR-PA BSI.

CONCLUSIONS

A simple score based on demographic and clinical factors allows stratification of individuals with bacteraemia according to their risk of MDR-PA BSI, and may help facilitate the use of rapid MDR-detection tools and improve early antibiotic appropriateness.

A review of the role of immune cells in acute kidney injury

Acute kidney injury (AKI) is a systemic disease occurring commonly in patients who are critically ill. Etiologies of AKI can be septic or aseptic (nephrotoxic, or ischemia-reperfusion injury). Recent evidence reveals that innate and adaptive immune responses are involved in mediating damage to renal tubular cells and in recovery from AKI. Dendritic cells, monocytes/macrophages, neutrophils, T lymphocytes, and B lymphocytes all contribute to kidney injury. Conversely, M2 macrophages and regulatory T cells are essential in suppressing inflammation, tissue remodeling and repair following kidney injury. AKI itself confers an increased risk for developing infection owing to increased production and decreased clearance of cytokines, in addition to dysfunction of immune cells themselves. Neutrophils are the predominant cell type rendered dysfunctional by AKI. In this review, we describe the bi-directional interplay between the immune system and AKI and summarize recent developments in this field of research.

Risk factors for mortality in patients with acute leukemia and bloodstream infections in the era of multiresistance

Objectives

We assess the epidemiology and risk factors for mortality of bloodstream infection (BSI) in patients with acute leukemia (AL).

Methods

Prospectively collected data of a cohort study from July 2004 to February 2016. Multivariate analyses were performed.

Results

589 episodes of BSI were documented in 357 AL patients, 55% caused by gram-positive bacteria (coagulase-negative staphylococci 35.7%, Enterococcus spp 10.8%) and 43.5% by gram-negative bacteria (E. coli 21%, PA 12%). We identified 110 (18.7%) multidrug-resistant (MDR) microorganisms, especially MDR-Pseudomonas aeruginosa (7%) and extended-spectrum beta-lactamase producing Enterobacteriaceae (7%). The 30-day mortality was 14.8%. Age (OR 3.1; 95% CI 1.7–5.7); chronic lung disease (4.8; 1.1–21.8); fatal prognosis according to McCabe index (13.9; 6.4–30.3); shock (3.8; 1.9–7.7); pulmonary infection (3.6; 1.3–9.9); and MDR-PA infections with inappropriate treatment (12.8; 4.1–40.5) were related to mortality. MDR-PA BSI was associated to prior antipseudomonal cephalosporin use (9.31; 4.38–19.79); current use of betalactams (2.01; 1.01–4.3); shock (2.63; 1.03–6.7) and pulmonary source of infection (9.6; 3.4–27.21).

Conclusions

MDR organisms were commonly isolated in BSI in AL. Inappropriate empiric antibiotic treatment for MDR-PA is the primary factor related to mortality that can be changed. New treatment strategies to improve the coverage of MDR-PA BSI should be considered in those patients with risk factors for this infection.

Febrile events in acute lymphoblastic leukemia: a prospective observational multicentric SEIFEM study (SEIFEM-2012/B ALL)

The purpose of the present study is to estimate the current incidence of febrile events (FEs) and infectious episodes in acute lymphoblastic leukemia (ALL) and evaluate the outcome. We analyzed data on all FEs in a cohort of patients affected by ALL admitted to 20 Italian hematologic centers during 21 months of observation from April 1, 2012 to December 31, 2013. Data about treatment phase, steroids, neutropenia, type and site of infection, and outcome of infection were collected. The population comprehended 271 ALL adult patients. Median age was 46 years old (range 19-75), M/F 1.1:1. We collected 179 FEs occurring during 395 different phases of treatment in 127 patients (45.3% incidence): remission induction treatment 53.1%, consolidation/maintenance 35.7%, treatment for a first or second relapse 44.3%, and refractory disease 85.7%. The incidence of FUO (fever of unknown origin) was 55/395 (13.9%). In the remaining cases, bacteria caused 92 FEs (23.2%), fungi 17 (4.3%), viruses 5 (1%). Mixed infections occurred in 10 cases mainly fungal+bacterial (9/10 cases). Neutropenia was mostly present at onset of FE (89.9% of FEs). Mortality rate was 11.7% (21/179) while 16 deaths occurred with evidence of infection (8.9%). Age > 60 years, neutropenia, poor performance status, steroids, refractory disease, and mixed infections significantly correlated with infection-related mortality. A statistically significant association with mortality was observed also for pulmonary localization and bacteremia. Our study describes the real-life epidemiological scenario of infections in ALL and identifies a subset of patients who are at higher risk for infection-related mortality.

[Clinical and bacteriological analysis of lymphoid tissue neoplasms patients with bacteria bloodstream infections]

Objective: To investigate the clinical status of lymphoid tissue neoplasms patients with bacteria bloodstream infections, bacteriology and drug susceptibility results, and provide the basis for rational clinical anti-infection option. Methods: A retrospectively analysis of clinical data and bacterial susceptibility test results of patients with bacteria bloodstream infections from September 2010 to December 2014 was conducted. Results: A total of 134 cases including 107 patients with bloodstream infections were enrolled. 84 cases were male, 50 cases were female, the median age was 31 (12-71) years old. 112 cases were agranulocytosis, and 106 cases were severe agranulocytosis (ANC<0.1×10(9)/L) . 27 cases underwent hematopoietic stem cell transplantation, 100 cases received chemotherapy[33 cases with VD (I) CP±L (vincristine+daunorubicin/idarubicin + cyclophosphamide + prednison±asparaginasum) induction chemotherapy, 41 cases with intensive chemotherapy of Hyper-CVAD/MA or MA (mitoxantrone+cytarabine) , 26 cases with other chemotherapy regimens], and 7 cases were infected without chemotherapy. 10 patients discharged from hospital owing to treatment abandoning, 120 cases were cured through anti-infective therapy, 2 patients died of bacteria bloodstream infections, 1 patient died of sudden cardiac, and 1 patient died of GVHD after allogenic hematopoietic stem cell transplantation. A total of 144 strains were isolated, including 108 strains (75.0%) of Gram-negative bacteria and 36 strains (25.0%) of Gram-positive cocci. The susceptibility of Gram-negative bacteria to the carbapenems was 98.00%, and the adjustment treatment rate of carbapenems was 3.0%. The susceptibility of Gram-negative bacteria to the other antibiotics was 60.30%, and the adjustment treatment rate was 90.5%. The susceptibility of Grampositive cocci to the carbapenems was 49.3%, and to glycopeptides and linezolid was 100.0%. Comparing all patients'empirical use of antimicrobial agents with the drugs susceptibility results of blood cultures, 80.1% of the patients'initial drug selection was sensitive. Conclusion: The lymphoid neoplasms patients experienced bacteria bloodstream infections most often after receiving the chemotherapy regimens of treating acute lymphoblastic leukemia. The majority type of bacteria was Gram-negative bacteria. Drug susceptibility test showed that susceptibility of Gram-negative bacteria to the carbapenems was the highest, and the treatment adjustment rate was obviously lower. The susceptibility of Gram-positive cocci to glycopeptides and linezolid was high, and which could be applied to the patients with Gram-positive cocci sepsis on basis of susceptibility results in general.

Reversal of Acute Kidney Injury-Induced Neutrophil Dysfunction: A Critical Role for Resistin

OBJECTIVES

To assess the reversibility of acute kidney injury-induced neutrophil dysfunction and to identify involved mechanisms.

DESIGN

Controlled laboratory experiment and prospective observational clinical study.

SETTING

University laboratory and hospital.

SUBJECTS

C57BL/6 wild-type mice.

PATIENTS

Patients with septic shock with or without acute kidney injury.

INTERVENTIONS

Murine acute kidney injury was induced by intraperitoneal injections of folic acid (nephrotoxic acute kidney injury) or by IM injections of glycerol (rhabdomyolysis-induced acute kidney injury). After 24 hours, we incubated isolated neutrophils for 3 hours in normal mouse serum or minimum essential medium buffer. We further studied the effects of plasma samples from 13 patients with septic shock (with or without severe acute kidney injury) on neutrophilic-differentiated NB4 cells.

MEASUREMENTS AND MAIN RESULTS

Experimental acute kidney injury significantly inhibited neutrophil migration and intracellular actin polymerization. Plasma levels of resistin, a proinflammatory cytokine and uremic toxin, were significantly elevated during both forms of acute kidney injury. Incubation in serum or minimum essential medium buffer restored normal neutrophil function. Resistin by itself was able to induce acute kidney injury-like neutrophil dysfunction in vitro. Plasma resistin was significantly higher in patients with septic shock with acute kidney injury compared with patients with septic shock alone. Compared with plasma from patients with septic shock, plasma from patients with septic shock and acute kidney injury inhibited neutrophilic-differentiated NB4 cell migration. Even after 4 days of renal replacement therapy, plasma from patients with septic shock plus acute kidney injury still showed elevated resistin levels and inhibited neutrophilic-differentiated NB4 cell migration. Resistin inhibited neutrophilic-differentiated NB4 cell migration and intracellular actin polymerization at concentrations seen during acute kidney injury, but not at normal physiologic concentrations.

CONCLUSIONS

Acute kidney injury-induced neutrophil dysfunction is reversible in vitro. However, standard renal replacement therapy does not correct this defect in patients with septic shock and acute kidney injury. Resistin is greatly elevated during acute kidney injury, even with ongoing renal replacement therapy, and is sufficient to cause acute kidney injury-like neutrophil dysfunction by itself.

Antimicrobial resistance patterns, clinical features, and risk factors for septic shock and death of nosocomial E coli bacteremia in adult patients with hematological disease: A monocenter retrospective study in China

The aim of this retrospective analysis was to evaluate the antimicrobial resistance, clinical features, and risk factors for septic shock and death of nosocomial E coli bacteremia in adult patients in a single hematological center in China. A retrospective case-control study of 157 adult hematological patients with 168 episodes of E coli bacteremia was initiated from April 2012 to July 2015. Antimicrobial susceptibility as well as antimicrobial co-resistance rates were analyzed. Clinical features and outcomes were also studied. In addition, risk factors for septic shock and death were investigated. Among the 553 positive blood isolates during the study period, the prevalence of E coli was 33.3% and ESBL production strains represented 61.9% of those examined. In all the E coli strains isolated, 85.6% were multidrug-resistance (MDR), 2.4% were extensive drug resistance (XDR), and 6.0% were resistant to carbapenems. More MDR phenotype was noted in ESBL-EC strains (98.6% vs 62.8%, P<.001) and isolates from neutropenic patients (98.6% vs 62.8%, P < .001). In the antimicrobial susceptibility test, carbapenems and amikacin exhibited not only higher in vitro activity against E coli (94.0% and 92.0%, respectively), but lower co-resistance rates to other antibiotics. Carbapenem resistant strains retained full sensitivity to tigecycline and 60% to amikacin. Piperacillin/tazobatam was the third sensitive drug to both ESBL-EC (77.1%) and non-ESBL-EC (86.0%). In our series, 81.6% episodes received appropriate initial antibiotic treatment and no significant decrease in it was found in bacteremia due to ESBL E coli and patients with neutropenia, septic shock. Septic shock was noted in 15.5% patients and the overall 30-day mortality rate was 21.7%. Multivariate analysis revealed that induction chemotherapy (OR 2.126; 95% CI 1.624-11.332; P = .003) and polymicrobial infection (OR 3.628; 95% CI 1.065-21.219; P = .041) were risk factors for septic shock, whereas male (OR 2.223; 95% CI 1.132-12.022; P < .01) and septic shock (OR 52.359; 95% CI 19.951-292.690; P = .030) were risk factors for death.In the hematology department, ESBL-producing and MDR are widely prevalent in E coli bacteremia which is still a major life-threatening problem, especially for patients with septic shock. For empirical antimicrobial therapy, combination based on aminoglycoside, especially amikacin, will be helpful to increase the antimicrobial coverage against ESBL-EC while combining tigecycline with aminoglycoside should be considered for seriously carbapenem-resistant infectious patients.

Bloodstream infections caused by Klebsiella pneumoniae in onco-hematological patients: clinical impact of carbapenem resistance in a multicentre prospective survey

The aim of this study was to identify risk factors for mortality in patients suffering from hematological malignancies (HMs) with bloodstream infections (BSIs) caused by Klebsiella pneumoniae (KP). We conducted a prospective cohort study on KP BSI in 13 Italian hematological units participating in the HEMABIS registry-SEIFEM group. The outcome measured was death within 21 days of BSI onset. Survivor and non-survivor subgroups were compared and Cox regression analysis was conducted to identify independent predictors of mortality. A total of 278 episodes of KP BSI were included in the study between January 2010 and June 2014. We found that 161 (57.9%) KP isolates were carbapenem resistant (CRKP). The overall 21-day mortality rate was 36.3%. It was significantly higher for patients with CRKP BSI (84/161, 52.2%) than for those with BSI caused by carbapenem susceptible KP (CSKP) (17/117, 14.5%; P < 0.001). Septic shock (HR 3.86), acute respiratory failure (HR 2.32), inadequate initial antimicrobial therapy (HR 1.87) and carbapenem resistance by KP isolates (HR 1.85) were independently associated with mortality. A subanalysis was conducted in only 149 patients with CRKP BSI who had received ≥48 hr of adequate antibiotic therapy, and combination therapy was independently associated with survival (HR 0.32). Our study shows that in recent years carbapenem resistance has dramatically increased in HM patients with KP BSI in Italy and is associated with a worse outcome. The optimal management of such infections and the definition of new empirical/targeted antimicrobial strategies in HM patients can still be considered unmet clinical needs. Am. J. Hematol. 91:1076-1081, 2016. © 2016 Wiley Periodicals, Inc.

Multidrug-resistant bacteria in hematology patients: emerging threats

Multidrug-resistant (MDR) bacteria, particularly Gram negatives, such as Enterobacteriaceae resistant to third-generation cephalosporins or carbapenems and MDR Pseudomonas aeruginosa, are increasingly frequent in hematology patients. The prevalence of different resistant species varies significantly between centers. Thus, the knowledge of local epidemiology is mandatory for deciding the most appr-opriate management protocols. In the era of increasing antibiotic resistance, empirical therapy of febrile neutropenia should be individualized. A de-escalation approach is recommended in case of severe clinical presentation in patients who are at high risk for infection with a resistant strain. Targeted therapy of an MDR Gram negative usually calls for a combination treatment, although no large randomized trials exist in this setting. Infection control measures are the cornerstone of limiting the spread of MDR pathogens in hematology units.

Bloodstream infections in patients with solid tumors

Little information is currently available regarding bloodstream infection (BSI) in patients with solid tumors who, for a variety of reasons, are particularly predisposed to develop this condition. In this review we focus on the incidence, epidemiology, clinical features, etiology, antimicrobial resistance, and outcomes of BSI of adult cancer patients with solid tumors. Most episodes of BSI occur in non-neutropenic patients, in whom the site of primary or metastatic tumor often serves as the portal of entry. The urinary tract and the abdomen are the most frequent sources of infection, and cholangitis is the most common recurrent source of BSI. Gram-negative bacilli are becoming the leading cause of BSI in patients with solid tumors, and the rate of multidrug resistance is increasingly being recognized. The case-fatality rate in patients with solid tumors and BSI is high, especially among those with comorbidities, advanced neoplasms, corticosteroid therapy, and shock at presentation.

Short-term Effects of Acute Kidney Injury

Acute kidney injury (AKI) is associated with significant short-term morbidity and mortality, which cannot solely be explained by loss of organ function. Renal replacement therapy allows rapid correction of most acute changes associated with AKI, indicating that additional pathogenetic factors play a major role in AKI. Evidence suggests that reduced renal cytokine clearance as well as increased cytokine production by the acutely injured kidney contribute to a systemic inflammation state, which results in significant effects on other organs. AKI seems to compromise the function of the innate immune system. AKI is an acute systemic disease with serious distant organ effects.

New Insight on Epidemiology and Management of Bacterial Bloodstream Infection in Patients with Hematological Malignancies

Bloodstream infections (BSI) are a significant cause of morbidity and mortality in onco-hematologic patients. The Gram-negative bacteria were the main responsible for the febrile neutropenia in the sixties; their impact declined due to the use of fluoroquinolone prophylaxis. This situation was followed by the gradual emergence of Gram-positive bacteria also following the increased use of intravascular devices and the introduction of new chemotherapeutic strategies. In the last decade, the Gram-negative etiology is raising again because of the emergence of resistant strains that make questionable the usefulness of current strategies for prophylaxis and empirical treatment. Gram-negative BSI attributable mortality is relevant, and the appropriate empirical treatment significantly improves the prognosis; on the other hand the adequate delayed treatment of Gram-positive BSI does not seem to have a high impact on survival. The clinician has to be aware of the epidemiology of his institution and colonizations of his patients to choose the most appropriate empiric therapy. In a setting of high endemicity of multidrug-resistant infections also the choice of targeted therapy can be a challenge, often requiring strategies based on off-label prescriptions and low grade evidence.

In this review, we summarize the current evidence for the best targeted therapies for difficult to treat bacteria BSIs and future perspectives in this topic. We also provide a flow chart for a rational approach to the empirical treatment of febrile neutropenia in a multidrug resistant, high prevalence setting.

Epidemiology and emerging resistance in bacterial bloodstream infections in patients with hematologic malignancies

BACKGROUND

The objective of this study was determine the frequency of bloodstream infections (BSIs) and the causative bacteria and their resistance patterns in patients with hematological malignancies (HMs) in a large tertiary care university hospital in Turkey over a 5-year period.

METHODS

A total of 2098 patients with HMs with 3703 neutropenic episodes were included. Patients were classified as high-risk (n = 843) and low-risk (n = 1255) groups and evaluated for frequency of BSIs, causative bacteria, and their resistance patterns.

RESULTS

The frequency of BSIs was 14.5%. The frequency of gram-negative BSIs in high-risk and low-risk groups was 10.7% and 5.4% (p < 0.001), respectively. The frequency of gram-positive BSIs in high-risk and low-risk groups was 7.0% and 3.9% (p < 0.001), respectively. Gram-negative bacteria predominated (52.6%), with Escherichia coli (17.3%) and Klebsiella spp. (11.0%) as the most frequent organisms. Coagulase-negative staphylococci (10.4%) and Corynebacterium spp. (6.3%) were the most common gram-positive bacteria (35.8%). The rate of extended-spectrum beta-lactamase (ESBL) production was 45% for E. coli and 58% for Klebsiella spp. Quinolone resistance was 58% for E. coli and 11% for Klebsiella spp.. The overall frequency of ceftazidime resistance in Pseudomonas aeruginosa was 28%, and 87% of Acinetobacter spp. were multidrug-resistant. Of Staphylococcus aureus isolates, 24.8% were resistant to methicillin.

CONCLUSION

The dominating causes of BSIs in patients with HMs in our hospital are resistant gram-negative bacteria, which has made empirical antimicrobial choice a highly challenging issue in this patient population.

Factors influencing mortality in neutropenic patients with haematologic malignancies or solid tumours with bloodstream infection

The purpose of this study was to identify factors influencing mortality in neutropenic patients with haematologic malignancies or solid tumours with bloodstream infection (BSI). All episodes of BSI occurring in adult neutropenic patients with haematologic malignancies or solid tumours were prospectively recorded from January 2006 to December 2013. We analysed the factors influencing mortality in both groups of patients. We documented 602 consecutive episodes of BSI; 510 occurred in patients with haematologic malignancies and 92 in patients with solid tumours. The overall case-fatality rates were 12% and 36%, respectively. Independent risk factors associated with a higher case-fatality rate in patients with haematologic malignancies were: intensive care unit admission (odds ratio (OR), 15.2; 95% confidence interval (CI), 5.4-42.7), advanced neoplasm (OR, 8.7; 95% CI, 2.9-25.7), corticosteroid therapy (OR, 7.0; 95% CI, 3-16.4), multidrug-resistant Gram-negative BSI (OR, 3.8; 95% CI, 1.2-11.8) and a Multinational Association for Supportive Care in Cancer risk score of <21 (OR, 3.1; 95% CI, 1.3-7.4). By contrast, coagulase-negative staphylococci BSI (OR, 0.04; 95% CI, 0.004-0.5) and empirical antibiotic combination therapy (OR, 0.1; 95% CI, 0.05-0.3) were found to be protective. Independent risk factors for overall case-fatality rate in patients with solid tumours were: shock at presentation (OR, 14.3; 95% CI, 3.2-63.8), corticosteroid therapy (OR, 10; 95% CI, 2.3-44) and advanced neoplasm (OR, 7.8; 95% CI, 1.4-41.4). Prognostic factors identified in this study may help to detect those patients at higher risk of death in each group. Medical intervention addressing some of these factors might improve the outcome of BSI in neutropenic patients with haematologic malignancies or solid tumours.