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

Shifting trends in bloodstream infection-causing microorganisms and their clinical impact in patients with haematologic malignancies in South Korea: A propensity score-matched study

BACKGROUND

This study aimed to identify recent trends in the epidemiology of bloodstream infection (BSI)-causing microorganisms among patients with haematologic malignancies (HMs) between 2011 and 2021, and to determine their impact on patient outcomes.

METHODS

This retrospective study included 6792 patients with HMs, of whom 1308 (19.3%) developed BSI within 1 y of diagnosis. The incidence of BSI-causing microorganisms was determined, and a propensity score-matched study was performed to identify risk factors for 28-d all-cause mortality in patients with HM.

RESULTS

A total of 6792 patients with HMs were enrolled. The cumulative incidence of BSI and neutropenia was significantly higher in the acute myeloid leukaemia and acute lymphoblastic leukaemia groups compared to other groups, and neutropenia and type of HMs were risk factors for the development of BSI. The annual incidence of coagulase-negative staphylococci (CoNS)-BSI decreased significantly (P < 0.001), whereas Klebsiella pneumoniae-BSI increased (P = 0.01). Carbapenem nonsusceptibility rates in K. pneumoniae isolates increased from 0.0% to 76.5% (P < 0.001). BSI caused by K. pneumoniae (adjusted odds ratio 2.17; 95% confidence interval 1.12-4.21) was associated with higher 28-d all-cause mortality compared to that caused by CoNS (adjusted odds ratio 0.86; 95% confidence interval 0.48-1.55).

CONCLUSION

The pathogenic spectrum of BSI-causing bacteria in patients with HMs gradually shifted from Gram-positive to Gram-negative, especially from CoNS to K. pneumoniae. Considering that K. pneumoniae-BSI had a significantly higher 28-d mortality rate than CoNS-BSI, this evolving trend could adversely impact the clinical outcomes of patients with HMs.

Hospital-acquired bloodstream infections in patients with cancer: current knowledge and future directions

Patients with cancer experience higher rates of preventable harm from hospital-acquired bloodstream infections (haBSIs) and central-line-associated bloodstream infections (CLABSIs) compared with the general hospital population. The prevention of haBSIs and CLABSIs in patients with cancer is an urgent priority, and requires standardized surveillance and reporting efforts. The application of haBSI and CLABSI definitions, classification systems and surveillance strategies for patients with cancer is complex, and there is wide variation in clinical practice. Existing systems were not designed explicitly for patients with cancer, and have different strengths and weaknesses in the cancer setting. For these reasons, epidemiological estimates of haBSIs and CLABSIs in patients with cancer also require careful interpretation. This complexity can be a barrier to identifying appropriate targets for intervention and reducing preventable harm. This review provides an overview of key concepts and challenges in haBSI surveillance and prevention specific to patients with cancer. In addition, this review summarizes the strengths and weaknesses of commonly used surveillance definitions and denominators in the setting of cancer care; existing surveillance practice; epidemiology of haBSIs and CLABSIs; prevention strategies; and current knowledge gaps. A global collaborative effort to harmonize the surveillance of hospital-acquired infections in patients with cancer would be invaluable to improve the accuracy and utility of existing data, advance efforts to prevent hospital-acquired infections, and improve patient safety.

Incidence of Invasive Infections Among Hemato-Oncology Patients with Significant Burden of Candida in Stool

Candidemia is a serious infection associated with increased mortality. It is unclear whether a high concentration of Candida in stool in patients with hematologic malignancies is associated with a higher risk for developing candidemia. In this observational historical study in patients hospitalized in hemato-oncology departments, we describe the association between gastrointestinal Candida colonization and the risk for candidemia and other severe outcomes. Data from 166 patients with heavy burden of Candida in stool were collected and compared to a control group of 309 patients with minimal or no Candida in stool, from 2005 to 2020. Severe immunosuppression and recent use of antibiotics were more common in heavily colonized patients. Outcomes of heavily colonized patients were worse as compared to the control group with statistical significance in 1-year mortality (53% vs. 37.5%, p = 0.001) and borderline statistical significance in candidemia rate (12.6% vs. 7.1%, p = 0.07). Risk factors for 1-year mortality were significant colonization of Candida in stool, older age and recent use of antibiotics. In conclusion, significant stool burden of Candida among hospitalized hemato-oncology patients may pose a risk for 1-year mortality and increased candidemia rate.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Background—Allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients are subject to major risks for bacterial bloodstream infections (BSIs), including emergent multidrug-resistant (MDR) organisms, which still represent the main cause of morbidity and mortality in transplanted patients. Methods: 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. Results: 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. Conclusions: 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.

Prevalence of bloodstream infection pathogens in hemato-oncological patients and predictors of carbapenem-resistant gram-negative bacterial infections during febrile neutropenia

BACKGROUND

Carbapenem-Resistant Gram-Negative (CRGN) Bloodstream Infections (BSI) represent a therapeutic challenge, especially in the context of Febrile Neutropenia (FN) in cancer patients.

METHODS

We characterized pathogens causing BSI in patients aged ≥18 years who had undergone systemic chemotherapy for solid or hematological cancers between 2012 and 2021 in Porto Alegre, Brazil. Predictors of CRGN were evaluated through a case-control analysis. Each case was matched to two controls from whom CRGN were not isolated and had the same sex and year of inclusion in the study.

RESULTS

From 6094 blood cultures evaluated, 1512 (24.8%) showed positive results. Gram-negative bacteria accounted for 537 (35.5%) of the isolated bacteria, of which 93 (17.3%) were carbapenem-resistant. From 105 patients included in the case-control analysis, all cases had baseline hematological malignancies (60% acute myeloid leukemia). Variables related to CRGN BSI in Cox regression analysis were the first chemotherapy session (p<0.01), chemotherapy performed in the hospital setting (p = 0.03), intensive care unit admission (p<0.01), and CRGN isolation in the previous year (p<0.01). Patients with CRGN BSI received 75% less empirical active antibiotics and had 27.2% higher 30-day mortality rates than controls.

CONCLUSIONS

A CRGN risk-guided approach should be considered for empirical antibiotic therapy in patients with FN.

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

BACKGROUND

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.

AIM

A retrospective case-control study was conducted to investigate the association between DTR-PA infection and clinical interventions, patient movement, antimicrobial use and comorbidities.

METHODS

Cases were patients colonized or infected with the outbreak strain of DTR-PA who had been admitted to hospital prior to their positive specimen. Exposures were extracted from medical records, and cases were compared with controls using conditional logistic regression. Environmental and microbiological investigations were also conducted.

FINDINGS

Seventeen cases and 51 controls were included. The final model included age [>65 years, adjusted OR (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 use of ciprofloxacin (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.

CONCLUSION

This study found that the use of fluoroquinolones is 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.

Utility of plasma cell-free DNA next-generation sequencing for diagnosis of infectious diseases in patients with hematological disorders

BACKGROUND

Plasma cell-free DNA Next-Generation Sequencing has been used as a non-invasive and comprehensive method for the etiological diagnosis of infectious diseases. However, only a handful of studies have described the real-world utility of this technique in patients with hematological disorders, a cohort of patients that are distinctive due to neutropenia and weakened immune functions.

METHODS

We retrospectively analyzed the results of plasma cell-free DNA sequencing performed on 184 and 163 specimens collected from hematological patients suspected of infections with (Group I) or without (Group II) neutropenia, respectively. The diagnostic performance and the clinical impact of plasma sequencing were comparatively evaluated to conventional microbiological tests and a composite reference standard (conventional tests combined with the clinical assessment).

RESULTS

The overall positive detection rate of plasma cell-free DNA sequencing was significantly higher than that of conventional microbiological tests (72.6% vs.31.4%, P < 0.001). The positive rate of conventional microbiological tests in Group I was lower than that in Group II (25.5% vs. 38.0%, P = 0.012). Combining plasma sequencing with conventional tests yielded a positive detection rate of 75.0% and 74.8% for these two groups, respectively. Using the composite reference standard, the sensitivity and specificity of plasma sequencing were 89.1% and 65.1%, respectively. The proportions of the positive impact of cell-free DNA sequencing results in the Group I were higher than in the Group II in terms of both diagnosis and treatment (diagnosis: 54.3% vs. 40.5%, P = 0.013; treatment: 45.7% vs.30.7%, P = 0.004). A total of 73 patients (21.0%) benefited from plasma sequencing through adjustment of the antibiotic regimen.

CONCLUSIONS

The diagnostic yield of conventional microbiological tests was low in patients with neutropenia. Combining conventional tests with plasma cell-free DNA sequencing significantly improved the detection rate for pathogens and optimized antibiotic treatment. Our findings on the clinical impact warrant confirmation through larger, multicenter, randomized controlled trials. Moreover, the cost-effectiveness of this testing strategy remains unknown and requires further exploration.

Pharmacokinetics of Vancomycin among Patients with Chemotherapy-Associated Febrile Neutropenia: Which Would Be the Best Dosing to Obtain Appropriate Exposure?

Previous research has determined that the required doses for treating febrile neutropenia with vancomycin are higher than the doses used conventionally. These recommendations have been made considering pharmacotherapeutic goals based on minimum concentration (Cmin) between 15–20 mg/L. This study was developed to evaluate dose recommendations based on the achievement of a target consisting of ratio of area under the curve over minimum inhibitory concentration (AUC24h/MIC) ≥400 in this population of individuals. This study was conducted in a referral hospital for cancer treatment, study participants received vancomycin doses of 1g every 12 h in 2-4-h infusions. Vancomycin was described by a two-compartment pharmacokinetic model with clearance dependent on the estimated glomerular filtration rate. Simulations were performed taking into account a reduced version of the model to establish the influence of controllable and non-controllable variables on the probability of achieving several PK-PD targets. A dose of 2.5g/day in patients with estimated glomerular filtration rate (eGFR) between 80 and 122mL/min/1.73m2 was adequate to achieve the pharmacotherapeutic target. A discrepancy was found between AUC-based and Cmin-based PK/PD indices, the former being affected by the dose and creatinine clearance while the latter highly influenced by the interval between doses.

Treatment of severe multi-drug resistant Pseudomonas aeruginosa infections

Pseudomonas aeruginosa is the microorganism most frequently involved in the main ICU-acquired infections, with special importance in ventilator associated pneumonia. Its importance lies, in addition to its high incidence in critically ill patients, in the severity of the infections it causes and in the difficulty of its antimicrobial treatment, directly related to the high percentage of resistance to antibiotics classically considered first-line. New active antibiotics have recently been developed against Pseudomonas aeruginosa, even against multi-drug resistant strains. This review analyzes both the differential characteristics of Pseudomonas aeruginosa infections and the new therapeutic options, focusing on multi-drug resistant Pseudomonas aeruginosa.

Novel Pseudomonas aeruginosa Strains Co-Harbouring bla NDM-1 Metallo β-Lactamase and mcr-1 Isolated from Immunocompromised Paediatric Patients

Background

The rising resistance to carbapenems in Gram-negative bacteria worldwide poses a major clinical and public health risk. This study aimed to characterise carbapenem- and colistin-resistance genes, bla NDM-1 and mcr-1 located on IncX4 plasmid in MDR Pseudomonas aeruginosa, isolated from paediatric patients undergoing chemotherapy as a result of leukaemia.

Methods

In this study, six carbapenem-resistant strains of P. aeruginosa were isolated from two paediatric patients under chemotherapy treatment (1.8 years old female and 2.1 years male) from the Shenzhen Hospital, China, in the year 2019. Isolates were screened for conventional antibiotics such as tobramycin, cefepime, imipenem, and ciprofloxacin in additional colistin by using the broth dilution method. Furthermore, resistance determinants: mcr-1, bla NDM-1, bla KPC-1, and bla GES were screened using PCR and sequencing followed by multi-locus sequence typing. The horizontal gene transfer and location of mcr-1 and bla NDM-1 were determined by a liquid mating assay. In addition, Incompatibility type (Inc), PCR-based replicon type, and subgroup (MOB) of plasmid were studied.

Results

The screening for conventional antibiotics isolates showed 100% resistance to all the tested antibiotics except tobramycin. All isolates harboured carbapenemase encoding bla NDM-1, of which three also had mcr-1 located on a single IncX4 transferable plasmid. MLST typing revealed that four strains had a novel (new) STs type, while two belonged to ST1966.

Conclusion

This study identified for the first time colistin- and carbapenem-resistant MDR P. aeruginosa in paediatric patients with leukaemia in Shenzhen, China. It highlights the need for continuous surveillance in high-risk clones of MDR P. aeruginosa. Prudent use of antibiotics based on local antimicrobial susceptibility and clinical characteristics can help in reducing mortality in immunocompromised patients.

Bring it on: Top five antimicrobial stewardship challenges in transplant infectious diseases and practical strategies to address them

Antimicrobial therapies are essential tools for transplant recipients who are at high risk for infectious complications. However, judicious use of antimicrobials is critical to preventing the development of antimicrobial resistance. Treatment of multidrug-resistant organisms is challenging and potentially leads to therapies with higher toxicities, intravenous access, and intensive drug monitoring for interactions. Antimicrobial stewardship programs are crucial in the prevention of antimicrobial resistance, though balancing these strategies with the need for early and frequent antibiotic therapy in these immunocompromised patients can be challenging. In this review, we summarize 5 frequently encountered transplant infectious disease stewardship challenges, and we suggest strategies to improve practices for each clinical syndrome. These 5 challenging areas are: asymptomatic bacteriuria in kidney transplant recipients, febrile neutropenia in hematopoietic stem cell transplantation, antifungal prophylaxis in liver and lung transplantation, treatment of left-ventricular assist device infections, and Clostridioides difficile infection in solid-organ and hematopoietic stem-cell transplant recipients. Common themes contributing to these challenges include limited data specific to transplant patients, shortcomings in diagnostic testing, and uncertainties in pharmacotherapy.

Emergence of non-susceptibility during persistent Pseudomonas aeruginosa bacteraemia in haematopoietic cell transplant recipients and haematological malignancy patients

Background

Systematic studies pertaining to the emergence of resistance during therapy of Pseudomonas aeruginosa bloodstream infections (BSIs) in haematopoietic cell transplant (HCT) recipients and haematological malignancy (HM) patients are lacking.

Objectives

To determine how frequently non-susceptibility emerges during therapy of P. aeruginosa BSIs and to compare these findings with non-HCT/HM patients.

Patients and methods

P. aeruginosa BSIs that occurred at our institution between 1 July 2012 and 31 October 2019 in HCT/HM patients and non-HCT/HM patients were identified. Episodes in which bacteraemia persisted while on appropriate therapy (‘persistent BSI’) were evaluated for emergence of non-susceptibility during therapy.

Results

In total, 96 BSI episodes among 86 HCT/HM patients were analysed. Eight persistent BSI episodes (8.3%) occurred in eight patients (9.3%). Repeat susceptibility testing was performed in seven (87.5%) of these episodes. Non-susceptibility to the treatment agent emerged in five (71.4%) episodes and to any antipseudomonal agent in seven (100%) episodes. The 21 day mortality rate associated with persistent BSI was 87.5% (seven of eight), and it was 80% (four of five) among persistent BSI episodes in which non-susceptibility to the treatment agent emerged on therapy. Non-susceptibility to any antipseudomonal agent during persistent BSI emerged significantly more frequently in HCT/HM patients compared with non-HCT/HM patients.

Conclusions

Non-susceptibility emerges frequently during persistent P. aeruginosa BSIs in HCT/HM patients, and this is associated with a high mortality rate. Our findings have implications for the management of persistent P. aeruginosa BSIs in these patients. Larger studies are needed to confirm and expand on our findings.

Multidrug-resistant, gram-negative infections in high-risk haematologic patients: an update on epidemiology, diagnosis and treatment

PURPOSE OF REVIEW

Multidrug-resistant Gram-negative bacilli (MDR-GNB) infections are a significant cause of morbidity and mortality in high-risk hematologic patients. Early diagnosis and management of antibiotic treatment in these patients is a challenge for physicians. This review focuses on the latest literature reports that concern the epidemiology, diagnosis and treatment of MDR-GNB infections in this population.

RECENT FINDINGS

High-risk haematological patients have several risk factors that make them particularly susceptible to MDR-GNB infections. Few studies have examined the implementation of rapid diagnostic methods for multidrug resistance, and their impact on management in this population. Inappropriate empiric antibiotic treatment in these patients has been described frequently and is associated with poor outcomes.

SUMMARY

Knowledge of the local epidemiology of MDR-GNB is a basic requirement to guide empiric antibiotic treatments in each centre. New diagnosic tests might help in faster identification of MDR-GNB infections. Appropriate empiric antibiotic treatment is crucial for improving patients' prognosis. Important strategies to reduce inadequate antibiotic treatment include better risk stratification for MDR-GNB infection and the introduction of new, more broad-spectrum antibiotic therapies.

How representative is a point-of-care randomized trial? Clinical outcomes of patients excluded from a point-of-care randomized controlled trial evaluating antibiotic duration for Gram-negative bacteraemia: a multicentre prospective observational cohort study

OBJECTIVES

Patients included in randomized controlled trials (RCT) are poorly representative of the general population. We compared outcomes of patients excluded from the PIRATE trial, a point-of-care RCT evaluating antibiotic durations for Gram-negative bacteraemia, with those of enrolled patients.

METHODS

A prospective observational cohort study, 'EPCO' (Excluded Patients' Clinical Outcomes) included patients excluded from the PIRATE trial. As in PIRATE, whose patients were randomized to 7-day, 14-day, or C-reactive-protein (CRP)-guided antibiotic durations, EPCO's primary outcome was occurrence of clinical success at 30 days. We also compared baseline characteristics, outcome rates and treatment-effect estimates.

RESULTS

In all, 405 patients were included in EPCO and compared with the 503 PIRATE patients. Reasons for exclusion were mainly medical (317/405; 78%), the most frequent being complicated infection. Excluded patients had more co-morbidities (Charlson median 3 versus 1, p < 0.001). Bacteraemia was more often health-care-associated (26% versus 9%, p < 0.001). The 30-day success rate was significantly lower among EPCO patients (299/396; 76% versus 469/493; 95%, p < 0.001), but the success rate was not significantly different for those excluded for non-medical reasons (68/75; 91%, p 0.09). There was no significant difference in failure rates of EPCO patients according to their treatment duration (difference 7 days versus 14 days: p 0.75; 7 days versus CRP-correspondent: p 1.00; 14 days versus CRP-correspondent: p 1.00).

CONCLUSION

Although point-of-care-randomized trials are more inclusive and representative than traditional RCTs, they are still likely to select patients with lower failure risk. Shorter antibiotic durations were not associated with failure in either included or excluded patients, supporting the generalizability of the PIRATE trial's findings.

Understanding and Managing Sepsis in Patients With Cancer in the Era of Antimicrobial Resistance

Sepsis is a frequent complication in immunosuppressed cancer patients and hematopoietic stem cell transplant recipients that is associated with high morbidity and mortality rates. The worldwide emergence of antimicrobial resistance is of special concern in this population because any delay in starting adequate empirical antibiotic therapy can lead to poor outcomes. In this review, we aim to address: (1) the mechanisms involved in the development of sepsis and septic shock in these patients; (2) the risk factors associated with a worse prognosis; (3) the impact of adequate initial empirical antibiotic therapy given the current era of widespread antimicrobial resistance; and (4) the optimal management of sepsis, including adequate and early source control of infection, optimized antibiotic use based on the pharmacokinetic and pharmacodynamics changes in these patients, and the role of the new available antibiotics.

Nursing Care of Oncology Patients with Sepsis

OBJECTIVES

This article aims to update nurses on the incidence, diagnosis, and treatment of neutropenic sepsis and septic shock.

DATA SOURCES

A search of electronic databases, including PubMed and CINAHL, and e-books was performed, as was a search of clinically focused and point-of-care resources from the National Cancer Institute and UpToDate until December 2020.

CONCLUSION

Neutropenic sepsis and septic shock are oncological emergencies and can be fatal for patients undergoing anticancer treatment. Prompt and targeted treatment based on clinical signs is necessary to minimize further sequela, including morbidity and mortality.

IMPLICATIONS FOR NURSING PRACTICE

The oncology nurse must possess an understanding of the risk factors, presenting signs, and initial management of a neutropenic fever, sepsis, and septic shock. Early identification and initiation of treatments in patients in sepsis and septic shock will allow the oncology nurse to intervene with speed, skill, and confidence while working within the multidisciplinary team to provide the best outcome based on current evidence.

Risk Factors and Outcomes of Antibiotic-resistant Pseudomonas aeruginosa Bloodstream Infection in Adult Patients With Acute Leukemia

BACKGROUND

Pseudomonas aeruginosa (PA) bloodstream infection (BSI) is a common complication in patients with acute leukemia (AL), and the prevalence of antibiotic-resistant strains poses a serious problem. However, there is limited information regarding antibiotic resistance, clinical characteristics, and outcomes of PA BSI in AL patients. This study explored characteristics associated with the clinical outcomes of AL patients with PA BSI and analyzed factors associated with BSI caused by multidrug-resistant (MDR) or carbapenem-resistant strains.

METHODS

This single-center retrospective study enrolled hospitalized AL patients who developed PA BSI during January 2014-December 2019. The Kaplan-Meier method was used to plot survival curves. Multivariate logistic regression analyses were also performed.

RESULTS

Of 293 eligible patients with PA BSI, 55 (18.8%) received inappropriate empirical antibiotic therapy within 48 hours of BSI onset, whereas up to 65.8% MDR-PA BSI patients received inappropriate empirical treatment. The 30-day mortality rate was 8.5% for all patients. However, the 30-day mortality rates were 28.9% and 5.5% in MDR-PA BSI and non-MDR-PA BSI patients, respectively (P < .001). On multivariate analysis, previous use of quinolones (odds ratio [OR], 5.851 [95% confidence interval {CI}, 2.638-12.975]) and piperacillin/tazobactam (OR, 2.837 [95% CI, 1.151-6.994]) were independently associated with MDR-PA BSI; and MDR-PA BSI (OR, 7.196 [95% CI, 2.773-18.668]), perianal infection (OR, 4.079 [95% CI, 1.401-11.879]), pulmonary infection (OR, 3.028 [95% CI, 1.231-7.446]), and age ≥55 years (OR, 2.871 [95% CI, 1.057-7.799]) were independent risk factors for 30-day mortality.

CONCLUSIONS

MDR increases mortality risk in PA BSI patients, and previous antibiotic exposure is important in MDR-PA BSI development. Rational antibiotic use based on local antimicrobial susceptibility and clinical characteristics can help reduce antibiotic resistance and mortality.

[Epidemiological analysis of pathogens causing bloodstream infections in department of hematology in Guangdong Province]

Objective: To evaluate the epidemiology of bacterial bloodstream infections in patients submitted to hematologic wards in southern China. Methods: A total of 50 teaching hospitals were involved based on the China Antimicrobial Resistance Surveillance System. The data of clinical isolates from blood samples were collected from January 1, 2019, to December 31, 2019. Antimicrobial susceptibility testing was conducted by the Kirby-Bauer automated systems, and the results were interpreted using the CLSI criteria. Results: The data of 1,618 strains isolated from hematologic wards in 2019 were analyzed, of which gram-negative bacilli and gram-positive cocci accounted for 71.8% and 28.2%, respectively. Of those, the five major species were most often isolated, including Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, coagulase-negative staphylococcus, and Streptococcus viridans. The prevalence rates of methicillin-resistant strains in Staphylococcus aureus and coagulase-negative staphylococcus were 19.7% and 80.6%, respectively. No gram-positive cocci were resistant to vancomycin, linezolid, and teicoplanin, and none of the enterococci were resistant to linezolid. The resistance rate of S. viridans to penicillin G was 6.9%, and those to ceftriaxone and cefotaxime were more than 25%. The resistance rate of E. coli and K. pneumoniae in Enterobacteriaceae was higher in children than that in adults. The resistance rate of K. pneumoniae to meropenem was 14.1%. The resistant rate of Enterobacter cloacae to carbapenem was more than 25%. P. aeruginosa was more sensitive to more antibiotics than 80%, but the resistance rate to meropenem in children was higher than that in adults (11.8% vs. 6.5%). The proportion of gram-positive cocci in the ICU and respiratory departments was higher than that in the hematology department. The detection rates of carbapenem-resistant E. coli and K. pneumoniae in the respiratory department were the lowest with 0.3% and 3.7%, respectively, while those of CRPA and CRAB in the hematology department were the lowest with 8.3% and 25.8%, respectively. The detection rate of all carbapenem-resistant organisms in the ICU was the highest among the three departments. Conclusion: The etiology and drug resistance of bacteria from blood samples in the hematology department are different from those in the ICU and respiratory departments. The proportions of K. pneumoniae, P. aeruginosa, E. cloacae, and S. viridans dominating in the department of Hematology were significantly higher than those in the ICU and respiratory departments in Guangdong region.

Microbiology of Bloodstream Infections in Children After Hematopoietic Stem Cell Transplantation: A Single-Center Experience Over Two Decades (1997-2017)

Background

Bloodstream infections (BSIs) occur frequently after hematopoietic stem cell transplantation (HSCT). We examined the microbiology of BSI in pediatric HSCT recipients over a 2-decade period at our institution to inform empirical antimicrobial prescribing and infection prevention strategies.

Methods

We conducted a retrospective cohort study of children (<18 years) who underwent HSCT at Duke University between 1997 and 2015. We used recurrent-event gap-time Cox proportional hazards models to determine the hazards of all-cause and cause-specific BSI according to HSCT year. We compared the median time to BSI by causative organism type and evaluated for temporal trends in the prevalence of antibiotic resistance among causative organisms.

Results

A total of 865 BSI occurred in 1311 children, including 412 (48%) Gram-positive bacterial, 196 (23%) Gram-negative bacterial, 56 (6%) fungal, 23 (3%) mycobacterial, and 178 (21%) polymicrobial BSI. The hazard of all BSIs did not change substantially over time during the study period, but the hazard of fungal BSIs declined over time during the study period (P = .04). Most fungal BSIs (82%) occurred in the first 100 days after HSCT, whereas mycobacterial BSIs occurred later after HSCT than BSIs caused by other organisms (P < .0001). The prevalence of vancomycin resistance among BSIs caused by Enterococcus faecium increased during the study period (P = .0007). The risk of 2-year mortality in children was increased with BSI (P = .02), Gram-negative bacterial BSI (P = .02), and fungal BSI (P < .0001).

Conclusions

Despite expanded practices for BSI prevention over the past several decades, the incidence of BSI remains high in pediatric HSCT recipients at our institution. Additional strategies are urgently needed to effectively prevent BSIs in this high-risk population.

Clinical Predictive Model of Multidrug Resistance in Neutropenic Cancer Patients with Bloodstream Infection Due to Pseudomonas aeruginosa

We aimed to assess the rate and predictive factors of bloodstream infection (BSI) due to multidrug-resistant (MDR) Pseudomonas aeruginosa in neutropenic cancer patients. We performed a multicenter, retrospective cohort study including oncohematological neutropenic patients with BSI due to P. aeruginosa conducted across 34 centers in 12 countries from January 2006 to May 2018. A mixed logistic regression model was used to estimate a model to predict the multidrug resistance of the causative pathogens. Of a total of 1,217 episodes of BSI due to P. aeruginosa, 309 episodes (25.4%) were caused by MDR strains. The rate of multidrug resistance increased significantly over the study period (P = 0.033). Predictors of MDR P. aeruginosa BSI were prior therapy with piperacillin-tazobactam (odds ratio [OR], 3.48; 95% confidence interval [CI], 2.29 to 5.30), prior antipseudomonal carbapenem use (OR, 2.53; 95% CI, 1.65 to 3.87), fluoroquinolone prophylaxis (OR, 2.99; 95% CI, 1.92 to 4.64), underlying hematological disease (OR, 2.09; 95% CI, 1.26 to 3.44), and the presence of a urinary catheter (OR, 2.54; 95% CI, 1.65 to 3.91), whereas older age (OR, 0.98; 95% CI, 0.97 to 0.99) was found to be protective. Our prediction model achieves good discrimination and calibration, thereby identifying neutropenic patients at higher risk of BSI due to MDR P. aeruginosa The application of this model using a web-based calculator may be a simple strategy to identify high-risk patients who may benefit from the early administration of broad-spectrum antibiotic coverage against MDR strains according to the local susceptibility patterns, thus avoiding the use of broad-spectrum antibiotics in patients at a low risk of resistance development.