Carbapenem-resistant Klebsiella pneumoniae colonization and infection is associated with lower overall survival in a cohort of haematopoietic stem-cell transplantation patients: mechanism of resistance and virulence by whole-genome sequencing

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.

Colonization by Extended-Spectrum β-Lactamase-Producing Enterobacterales and Bacteremia in Hematopoietic Stem Cell Transplant Recipients

BACKGROUND

Assessing the risk of multidrug-resistant colonization and infections is pivotal for optimizing empirical therapy in hematopoietic stem cell transplants (HSCTs). Limited data exist on extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) colonization in this population. This study aimed to assess whether ESBL-E colonization constitutes a risk factor for ESBL-E bloodstream infection (BSI) and to evaluate ESBL-E colonization in HSCT recipients.

METHODS

A retrospective analysis of ESBL-E colonization and BSI in HSCT patients was conducted from August 2019 to June 2022. Weekly swabs were collected and cultured on chromogenic selective media, with PCR identifying the β-lactamase genes. Pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS) assessed the colonizing strains' similarities.

RESULTS

Of 222 evaluated HSCT patients, 59.45% were colonized by ESBL-E, with 48.4% at admission. The predominant β-lactamase genes were blaTEM (52%) and blaSHV (20%). PFGE analysis did not reveal predominant clusters in 26 E. coli and 15 K. pneumoniae strains. WGS identified ST16 and ST11 as the predominant sequence types among K. pneumoniae. Thirty-three patients developed thirty-five Enterobacterales-BSIs, with nine being third-generation cephalosporin-resistant. No association was found between ESBL-E colonization and ESBL-BSI (p = 0.087).

CONCLUSIONS

Although the patients presented a high colonization rate of ESBL-E upon admission, no association between colonization and infection were found. Thus, it seems that ESBL screening is not a useful strategy to assess risk factors and guide therapy for ESBL-BSI in HSCT-patients.

A clinical predictive model for pre-transplantation Klebsiella pneumoniae colonization and relevance for clinical outcomes in patients receiving allogeneic hematopoietic stem cell transplantation

The purpose of this study is to establish a clinical prediction model to discriminate patients at high risk of Klebsiella pneumoniae (KP) colonization before allogeneic hematopoietic stem cell transplantation (allo-HSCT) and evaluate the impact of KP colonization on clinical outcomes after allo-HSCT. We retrospectively collected data from 2,157 consecutive patients receiving allo-HSCT between January 2018 and March 2022. KP colonization was defined as a positive test for KP from a pharyngeal or anal swab before allo-HSCT. Logistic regression was used to build a clinical prediction model. Cox regression analyses were performed to explore the effect of KP colonization on clinical outcomes. Among all the inpatients, 166 patients had KP colonization and 581 with no positive pathogenic finding before transplantation. Seven candidate predictors were entered into the final prediction model. The prediction model had an area under the curve of 0.775 (95% CI 0.723-0.828) in the derivation cohort and 0.846 (95% CI: 0.790-0.902) in the validation cohort. Statistically significantly different incidence rates were observed among patient groups with clinically predicted low, medium, and high risk for KP infection (P < 0.001). The presence of KP colonization delayed platelet engraftment (P < 0.001) and patients with KP colonization were more likely to develop KP bloodstream infections within 100 days after allo-HSCT (P < 0.0001). Patients with KP colonization had higher non-relapse mortality (P = 0.032), worse progression-free survival (P = 0.0027), and worse overall survival within 100 days after allo-HSCT (P = 0.013). Our findings suggest that increased awareness of risks associated with pre-transplantation bacterial colonization is warranted.IMPORTANCESeveral studies have identified that Klebsiella pneumoniae (KP) is among the most common and deadly pathogens for patients in hospital intensive care units and those receiving transplantation. However, there are currently no studies that evaluate the impact of KP colonization to patients undergoing allogeneic hematopoietic stem cell transplantation. Our results confirm that pre-existing KP colonization is relatively common in a hematology transplant ward setting and negatively affects post-transplantation prognosis. Our clinical prediction model for KP colonization can support early intervention in patients at high risk to avoid subsequent bloodstream infections and improve survival outcomes. Altogether, our data suggest that increased awareness of risks associated with pre-transplantation bacterial colonization is warranted. Future studies are needed to confirm these findings and to test early intervention strategies for patients at risk of complications from KP infection.

Carbapenem-resistant Klebsiella pneumoniae bloodstream infections in haematological malignances and hematopoietic stem cell transplantation: Clinical impact of combination therapy in a 10-year Brazilian cohort

Bacterial bloodstream infections (BSI) are a common threat among patients with haematological malignancies (HM) and hematopoietic stem cell transplant recipients (HSCT). The purpose of this research was to describe clinical and microbiological aspects of BSI caused by carbapenem-resistant Klebsiella pneumoniae (CRKp) and assess risk factors associated with 30-day mortality in a 10-year cohort of haematological patients. A total of 65 CRKp-BSI episodes occurring in HM patients and HSCT recipients and CRKp-BSI between January 2010 and December 2019 were retrospectively studied. Acute leukemias were the most frequently observed underlying disease (87.7%) and 18 patients (27.7%) received HSCT. Mucosal barrier injury in the gastrointestinal tract was the primary cause of bacteremia (86.1%). Also, 14 individuals (21.6%) had an Invasive Fungal Disease (IFD) throughout the episode. Regarding treatment, in 31 patients (47.7%) empirical therapy was deemed appropriate, whereas 33 (50.8%) patients received a combination therapy. Microbiological data revealed that the majority of isolates (53-58%) had the Polymyxin B co-resistance phenotype, while amikacin resistance was less common (16 samples, or 24.7%). The mortality rates at 14 and 30 days were 32.3% and 36.9%, respectively. In a multivariate Cox regression analysis, prompt appropriate antibiotic administration within three days was associated with a better outcome (Adjusted Hazard Ratio [aHR]: 0.33; 95% Confidence Interval [CI]: 0.14-0.76; p = 0.01), whereas hypotension at presentation (aHR: 3.88; 95% CI: 1.40-10.74; p = 0.01) and concurrent IFD (aHR: 2.97; 95% CI: 1.20-7.37; p = 0.02) were independently associated with death within 30 days. Additionally, a favorable correlation between combination therapy and overall survival was found (aHR: 0.18; 95%CI: 0.06-0.56; p = 0.002). In conclusion, 30-day mortality CRKp-BSI was elevated and most of the isolates were polymyxin B resistant. Early appropriate antimicrobial treatment and the use of combination therapy were linked to a better outcome.

Colonization by multidrug-resistant bacteria in hematological patients undergoing hematopoietic stem cell transplantation and clinical outcomes: A single-center retrospective cohort study

BACKGROUND

Bloodstream infections are a leading cause of death in patients who undergo hematopoietic stem cell transplantation (HSCT) and are more severe when caused by multidrug-resistant (MDR) bacteria. This study proposed to investigate if colonization by MDR bacteria negatively affects the clinical outcomes in hematological patients after HSCT, as well as to evaluate possible risk factors for death due to bacteremia by the same colonizing agent.

METHODS

A single-center retrospective cohort study was conducted with 405 hematological patients submitted to a single HSCT procedure between 2015 and 2021. Patients were classified as colonized (n = 132) or noncolonized (n = 273) based on the surveillance cultures from D-30 to D+30 of transplantation, and their relevant clinical and laboratory data were collected until D+100.

RESULTS

Colonization by MDR bacteria increased blood culture positivity by all micro-organisms and also specifically by MDR bacteria, with a more pronounced effect when caused by carbapenemase-producing Klebsiella pneumoniae. Patients colonized with carbapenem-resistant K. pneumoniae had increased overall mortality (HR = 4.07, 95% CI 1.85-8.91, P = .0005) and had prolonged hospital length of stay in the context of autologous transplantation. Risk factors for death due to bacteremia by the same colonizing agent were neutropenia, colonization by carbapenem-resistant K. pneumoniae and use of high-dose total body irradiation in conditioning.

CONCLUSION

Hematological patients colonized by MDR bacteria presented a higher incidence of bloodstream infections, and colonization by carbapenemase-producing K. pneumoniae was associated with reduced overall survival.

Epidemiology, Drug Resistance, and Risk Factors for Mortality Among Hematopoietic Stem Cell Transplantation Recipients with Hospital-Acquired Klebsiella pneumoniae Infections: A Single-Center Retrospective Study from China

Objective

Infection is the most common complication and cause of death after hematopoietic stem cell transplantation (HSCT). Our study aims to investigate the clinical characteristics and risk factors for death of Klebsiella pneumoniae infections in HSCT recipients, so as to provide evidence for guiding antibiotic use and improving prognosis in the future.

Methods

The epidemiology, clinical manifestations and drug resistance rate with K. pneumoniae infections among HSCT recipients between January 1, 2012 and September 30, 2021 were retrospectively reviewed. Logistic regression model and Cox regression model were respectively used to determine the risk factors for carbapenem-resistant Klebsiella pneumoniae (CRKP) acquisition and death.

Results

Fifty-nine HSCT recipients suffered from K. pneumoniae infections, with a mortality rate of 42.4%. The most common site was lung, followed by blood stream. The resistance rate of K. pneumoniae to various clinically common antibiotics was high, especially CRKP, which was only sensitive to amikacin and tigecycline. Independent risk factor for CPKP acquisition was a previous infection within 3 months before transplantation (OR=10.981, 95% CI 1.474–81.809, P=0.019). Independent risk factors for mortality included interval from diagnosis to transplantation > 180 days (HR=3.963, 95% CI 1.25–12.561, P=0.019), engraftment period > 20 days (HR=8.015, 95% CI 2.355–27.279, P=0.001), non-use of anti-CMV immunoglobulin/rituximab after transplantation (HR=10.720, 95% CI 2.390–48.089, P=0.002), and PCT > 5 μg/L (HR=5.906, 95% CI 1.623–21.500, P=0.007).

Conclusion

K. pneumoniae infection has become a serious threat for HSCT recipients, which reminds us to pay enough attention and actively seek new strategies.