Pseudomonas aeruginosa Bloodstream Infections in Patients with Cancer: Differences between Patients with Hematological Malignancies and Solid Tumors

Clinical Characteristics, Risk Factors and Prognosis of Carbapenem-Resistant Pseudomonas aeruginosa Bloodstream Infections in Cancer Patients: An 8-year Retrospective Study in a Tertiary Cancer Hospital

Purpose

To ascertain clinical characteristics, risk factors and prognosis of bloodstream infection (BSI) caused by carbapenem-resistant Pseudomonas aeruginosa (CRPA) among cancer patients with solid tumors (ST) and hematological malignancies (HM).

Methods

A retrospective study (January 2015 to December 2023) was performed on the health records of cancer patients with Pseudomonas aeruginosa (PA) BSI at a tertiary cancer hospital in China. Ninety-two CRPA BSI cases were randomly paired with contemporaneous carbapenem-sensitive Pseudomonas aeruginosa (CSPA) BSI cases at a ratio of 1:1. Multivariate logistic regression analysis was performed to identify risk factors associated with the development of CRPA BSI and Cox regression for mortality rates. Survival probability was evaluated using the Kaplan-Meier estimator. Between-group survival differences were analyzed using the Log rank test and Hazard ratios (HR) were calculated to quantify mortality risk disparities.

Results

A total of 361 cancer patients with PA BSI were included, 25.5% (92/361) of which were infected with CRPA. Among the 184 enrolled patients (48 with ST, 136 with HM), the independent risk factors for developing CRPA BSI were platelet counts and recent carbapenem use within 90 days in patients with ST. Presence of multidrug-resistant P. aeruginosa (MDRPA) and exposure to carbapenems within 90 days were the risk factors for developing CRPA BSI in patients with HM. The 30-day mortality of CRPA BSI was 37.5% and 35.3% in patients with ST and HM, respectively. Additionally, higher Pitt bacteremia score (PBS) was distinctly associated with increased 30-day mortality in cancer patients suffering from CRPA BSI (HR 1.672, 95% CI 1.309-2.135, p< 0.001).

Conclusion

The mortality rates of CRPA BSI are notably high in both patients with ST and HM. The risk factors for CRPA BSI and mortality may guide and optimize the management of CRPA BSI in cancer patients.

Effect of empiric antibiotics against Pseudomonas aeruginosa on mortality in hospitalized patients: a systematic review and meta-analysis

BACKGROUND

Empiric antibiotics active against Pseudomonas aeruginosa are recommended by professional societies for certain infections and are commonly prescribed for hospitalized patients. The effect of this practice on mortality is uncertain.

METHODS

A systematic literature search was conducted using Embase, Medline, PubMed, Web of Science, Cochrane, Scopus and Google Scholar from earliest entry through 9 October 2023. We included studies of patients hospitalized with P. aeruginosa infections that compared mortality rates depending on whether patients received active empiric antibiotics.

RESULTS

We found 27 studies of 12 522 patients that reported adjusted OR of active empiric antibiotics on mortality. The pooled adjusted OR was 0.40 (95% CI, 0.32-0.50), favouring active empiric antibiotics. In practice, the mortality effect of empiric antibiotics against P. aeruginosa depends on the prevalence of P. aeruginosa and baseline mortality. The estimated absolute mortality benefit was 0.02% (95% CI, 0.02-0.02) for soft tissue infections, 0.12% (95% CI, 0.10-0.13) for urinary tract infections and community-acquired pneumonia, 0.3% (0.25-0.34) for sepsis without shock, 1.1% (95% CI, 0.9-1.4) for septic shock and 2.4% (95% CI, 1.9-2.8) for nosocomial pneumonia.

CONCLUSIONS

The mortality effect for empiric antibiotics against P. aeruginosa depends crucially on the prevalence of P. aeruginosa and baseline mortality by type of infection. For soft tissue infections, urinary tract infections and community-acquired pneumonia, the mortality benefit is low. Meaningful benefit of empiric antibiotics against P. aeruginosa is limited to patients with approximately 30% mortality and 5% prevalence of P. aeruginosa, which is largely limited to patients in intensive care settings.

Risk factors and outcome of Pseudomonas aeruginosa bloodstream infections (PABSI) in hematological patients: a single center retrospective cohort study

PURPOSE

Bloodstream infections caused by Pseudomonas aeruginosa (PABSI) in hematological patients are associated with high morbidity and mortality. We investigated the epidemiology, risk factors, and outcomes of PABSI at our center.

METHODS

All adult hematological patients with PABSI between January 2013 and July 2023 were included. Demographic and clinical characteristics, antimicrobial susceptibilities, antibiotic therapy, fluoroquinolone-prophylaxis, source of infection, and 30-day outcome were recorded. Descriptive statistics, tests for difference, and logistic regression models were performed.

RESULTS

Fifty patients with PABSI were identified with a median age of 58.5 years (range 24-78). 37 patients (74%) had severe neutropenia, 20 (40%) received allogeneic HSCT, and 29 (58%) had acute leukemia. A total of 34 (68%) had received timely appropriate anti-pseudomonal antibiotic therapy. The most common presumed cause of PABSI was mucositis (n = 16, 32%), followed by pneumonia (8, 16%) and skin and soft tissue infections (n = 6, 12%). Empirical combination therapy was used in 16 (32%) patients, while targeted combination therapies were used in 27 (54%) patients. P. aeruginosa detection led to treatment change in 31 (62%) cases. The overall 30-day survival rate was 78% (n = 39). Carbapenem-resistance occurred in 34% (n = 17), and multidrug-resistance (MDR) in 20% (n = 10). Prior antibiotic exposure was associated with resistance. Appropriate antibiotic therapy was associated with survival, whereas antibiotic resistance and organ infection were associated with a fatal outcome.

CONCLUSION

Prior antibiotic exposure in hematological patients is associated with resistance in PABSI, which is a major risk factor for a fatal outcome. Antibiotic stewardship efforts should be intensified and fluoroquinolone prophylaxis needs to be reconsidered.

Sex-Disaggregated Analysis of Central Venous Catheter-Related Bloodstream Infections in Patients with Cancer

INTRODUCTION

Men are generally more susceptible to bacterial infections than women. Central venous catheters (CVCs), often used to administer systemic treatment in patients with cancer, are an important source of infection. However, little is known about sex-specific differences of CVC-related bloodstream infections (CRBSIs) in patients with cancer. This study aimed to compare CRBSIs in men versus women in a large cohort of patients with cancer.

METHODS

Data were derived from the SECRECY registry including nonselected patients with centrally inserted non-tunneled internal jugular or subclavian vein CVCs in 10 hematology and oncology sites in Germany. Only CRBSIs classified as definite CRBSI (dCRBSI) or probable CRBSI were included, and the combination of both was summarized as dpCRBSI. CVCs were matched 1:1 for underlying disease, anatomic site of CVC insertion, type of CVC dressing, antimicrobial coated CVC, complicated CVC insertion, and CVC in situ time by propensity score matching (PSM). Endpoints were CRBSI rates and incidences in CVCs inserted in men versus women.

RESULTS

A total of 5,075 CVCs registered from March 2013 to March 2024 were included in the analysis, of which 3,024 comprise the PSM cohort. A total of 1,512 (50.0%) CVCs were inserted in men. Underlying diseases mainly were hematological malignancies (96.4%). While there was no statistically significant difference between men and women in the dCRBSI rate (5.4% vs. 4.1%; p = 0.12) and the dCRBSI incidence (3.8 vs. 2.9/1,000 CVC days; p = 0.11), the rate of dpCRBSI (9.9% vs. 6.7%; p = 0.002) and the dpCRBSI incidence (7.0 vs. 4.7/1,000 CVC days; p = 0.002) were significantly higher in men versus women. The proportion of coagulase-negative staphylococci as causative agent of both dCRBSI and dpCRBSI was higher in men than in women (58.8% vs. 41.2%; p = 0.07 and 61.5% vs. 38.5%; p = 0.002, respectively). A multivariable regression revealed neutropenia as an independent risk factor for dCRBSI and male sex as risk factor for dCRBSI and dpCRBSI.

CONCLUSION

In patients with hematological malignancies, men have a higher risk of CRBSI than women. This finding may be attributed to the high number of jugular vein-inserted CVCs, which in men may be associated with higher rates of skin colonization than in women. Special preventive measures such as earlier removal of CVCs in men may be studied in future.

INTRODUCTION

Men are generally more susceptible to bacterial infections than women. Central venous catheters (CVCs), often used to administer systemic treatment in patients with cancer, are an important source of infection. However, little is known about sex-specific differences of CVC-related bloodstream infections (CRBSIs) in patients with cancer. This study aimed to compare CRBSIs in men versus women in a large cohort of patients with cancer.

METHODS

Data were derived from the SECRECY registry including nonselected patients with centrally inserted non-tunneled internal jugular or subclavian vein CVCs in 10 hematology and oncology sites in Germany. Only CRBSIs classified as definite CRBSI (dCRBSI) or probable CRBSI were included, and the combination of both was summarized as dpCRBSI. CVCs were matched 1:1 for underlying disease, anatomic site of CVC insertion, type of CVC dressing, antimicrobial coated CVC, complicated CVC insertion, and CVC in situ time by propensity score matching (PSM). Endpoints were CRBSI rates and incidences in CVCs inserted in men versus women.

RESULTS

A total of 5,075 CVCs registered from March 2013 to March 2024 were included in the analysis, of which 3,024 comprise the PSM cohort. A total of 1,512 (50.0%) CVCs were inserted in men. Underlying diseases mainly were hematological malignancies (96.4%). While there was no statistically significant difference between men and women in the dCRBSI rate (5.4% vs. 4.1%; p = 0.12) and the dCRBSI incidence (3.8 vs. 2.9/1,000 CVC days; p = 0.11), the rate of dpCRBSI (9.9% vs. 6.7%; p = 0.002) and the dpCRBSI incidence (7.0 vs. 4.7/1,000 CVC days; p = 0.002) were significantly higher in men versus women. The proportion of coagulase-negative staphylococci as causative agent of both dCRBSI and dpCRBSI was higher in men than in women (58.8% vs. 41.2%; p = 0.07 and 61.5% vs. 38.5%; p = 0.002, respectively). A multivariable regression revealed neutropenia as an independent risk factor for dCRBSI and male sex as risk factor for dCRBSI and dpCRBSI.

CONCLUSION

In patients with hematological malignancies, men have a higher risk of CRBSI than women. This finding may be attributed to the high number of jugular vein-inserted CVCs, which in men may be associated with higher rates of skin colonization than in women. Special preventive measures such as earlier removal of CVCs in men may be studied in future.

Impact of adequate empirical combination therapy on mortality in septic shock due to Pseudomonas aeruginosa bloodstream infections: a multicentre retrospective cohort study

OBJECTIVES

To determine the association of adequate empirical combination therapy (AECT) with 30-day all-cause mortality in patients with septic shock due to Pseudomonas aeruginosa bloodstream infections (BSI).

METHODS

This multicentre, retrospective cohort study analysed data from 14 public hospitals in Italy, including all consecutive adult patients admitted during 2021-2022 with septic shock due to P. aeruginosa BSI. We compared the outcomes of patients receiving AECT to those on adequate empirical monotherapy (AEMT) using Cox regression analyses.

RESULTS

Of the 98 patients who received adequate empirical antibiotic treatment for septic shock due to P. aeruginosa BSI, 24 underwent AECT and 74 were given AEMT. AECT was associated with a lower 30-day all-cause mortality (25%, six out of 24) compared to AEMT (56.8%, 42 out of 74; P = 0.007). Multivariate Cox regression analysis indicated AECT as the only factor significantly associated with improved survival (aHR 0.30; 95% CI 0.12-0.71; P = 0.006). By contrast, the use of monotherapy or combination therapy in the definitive regimen did not influence mortality (aHR 0.73; 95% CI 0.25-2.14; P = 0.568).

CONCLUSIONS

AECT may be associated with reduced mortality compared to monotherapy in septic shock patients due to P. aeruginosa BSI. However, the administration of definitive adequate monotherapy or combination therapy yields similar outcomes, suggesting that once susceptibility is documented, switching to a single active in vitro drug is safe and feasible. Further studies are recommended to validate these findings.

Clinical characteristics and outcomes of persistent bacteremia in patients with head and neck cancer in a tertiary care hospital

Introduction

Compared to other cancers, research on bloodstream infection in head and neck cancer is scarce, lacking comparative studies on persistent versus transient bacteremia outcomes.

Methods

This retrospective survey examined patients with head and neck cancer undergoing blood culture at our center from June 2009 to May 2023. Blood culture-positive cases suspected of infection were divided into persistent bacteremia and transient bacteremia groups. We investigated their clinical, epidemiological, and microbiological features, including risk factors for persistent bacteremia and mortality. The primary outcome was 90-day mortality.

Results

In this 97-patient cohort, 14 (14%) cases were assigned to the persistent bacteremia group. Catheter-related bloodstream infections were the leading cause of infection in both groups, consistently contributing to a high proportion of overall bloodstream infections. The mortality rate was generally higher in the persistent bacteremia group than in the transient bacteremia group (odds ratio [OR], 2.6; 95% confidence interval [CI], 0.6-11.1), particularly in the non-clearance subgroup (OR, 9; 95% CI, 0.5-155.2). Pyogenic spondylitis was a key risk factor for persistent bacteremia, while hypoalbuminemia increased mortality.

Conclusion

In patients with bacteremia and head and neck cancer, persistent bacteremia was associated with higher mortality than was transient bacteremia. Adittionally, bacteremia clearance in persistent bacteremia is thus crucial for prognostic improvement.

Pathogenic spectrum and drug resistance of bloodstream infection in patients with acute myeloid leukaemia: a single centre retrospective study

Background

Bloodstream infection (BSI) represent a prevalent complication in haematological malignancies (HMs). Typically, Patients with BSI usually undergo empirical treatment pending pathogen identification. The timely and effective management of BSIs significantly influences patient prognosis. However, pathogen distribution in BSIs exhibits regional variation. In this study, we investigated the clinical characteristics, pathogen spectrum, drug resistance, risk factors of short-term prognosis and long-term prognostic factors of acute myeloid leukemia (AML) patients with BSI at Zhejiang Provincal People's Hospital.

Methods

From 2019 to 2021, a total of 56 AML patients with BSI were treated in the Department of Haematology at Zhejiang Province People's Hospital. Data regarding pathogen spectrum and drug resistance were collected for analysis. The patients were stratified into non-survivor cohort and survivor cohort within 30 days after BSI, and the predictors of 30-days mortality were identified through both univariate and multivariate Logistic regression analyses. Furthermore, Kaplan-Meier survival analysis and Cox regression analysis were employed to ascertain the risk factors associated with poor prognosis in AML patients complicated by BSI.

Results

A total of 70 strains of pathogenic bacteria were isolated from 56 AML patients with BSI. Gram-negative bacteria constituted the predominant pathogens (71.4%), with Klebsiella pneumoniae being the most prevalent (22.9%). Gram-positive bacteria and fungi accounted for 22.9% and 5.7%, respectively. Univariate and multivariate analyses revealed significant differences in total protein, albumin levels, and the presence of septic shock between the non-survivor cohort and the survior cohort 30 days post-BSI. COX regression analysis showed that agranulocytosis duration exceeding 20 days (HR:3.854; 95% CI: 1.451-10.242) and septic shock (HR:3.788; 95% CI: 1.729-8.299) were independent risk factors for poor prognosis in AML patients complicated by BSI. Notably, the mortality rate within 30 days after Stenotrophomonas maltophilia infection was up to 71.4%.

Conclusions

In this study, Gram-negative bacteria, predominantly Klebsiella pneumoniae, constituted the primary pathogens among AML patients with BSIs. Serum albumin levels and the presence of septic shock emerged as independent risk factors for mortality within 30 days among AML patients with BSI. In terms of long-term prognosis, extended agranulocytosis duration exceeding 20 days and septic shock were associated with elevated mortality rates in AML patients with BSI. Additionally, in our centre, Stenotrophomonas maltophilia infection was found to be associated with a poor prognosis. Early intervention for Stenotrophomonas maltophilia infection in our centre could potentially improve patient outcomes.

In vitro investigation of relationship between quorum-sensing system genes, biofilm forming ability, and drug resistance in clinical isolates of Pseudomonas aeruginosa

BACKGROUND

Pseudomonas aeruginosa is an opportunistic pathogen in the health-care systems and one of the primary causative agents with high mortality in hospitalized patients, particularly immunocompromised. The limitation of effective antibiotic administration in multidrug-resistant and extensively drug-resistant P. aeruginosa isolates leads to the development of nosocomial infections and health problems. Quorum sensing system contributes to biofilm formation, expression of bacterial virulence factors, and development of drug resistance, causing prolonged patient infections. Therefore, due to the significance of the quorum sensing system in increasing the pathogenicity of P. aeruginosa, the primary objective of our study was to investigate the frequency of quorum sensing genes, as well as the biofilm formation and antibiotic resistance pattern among P. aeruginosa strains.

METHODS

A total of 120 P. aeruginosa isolates were collected from different clinical specimens. The disk diffusion method was applied to detect the antibiotic resistance pattern of P. aeruginosa strains. Also, the microtiter plate method was carried out to evaluate the biofilm-forming ability of isolates. Finally, the frequency of rhlI, rhlR, lasI, and lasR genes was examined by the polymerase chain reaction method.

RESULTS

In total, 88.3% P. aeruginosa isolates were found to be multidrug-resistant, of which 30.1% had extensively drug-resistant pattern. The highest and lowest resistance rates were found against ceftazidime (75.0%) and ciprofloxacin (46.6%), respectively. Also, 95.8% of isolates were able to produce biofilm, of which 42.5%, 33.3%, and 20.0% had strong, moderate, and weak biofilm patterns, respectively. The frequency of quorum sensing genes among all examined strains was as follows: rhlI (81.6%), rhlR (90.8%), lasI (89.1%), and lasR (78.3%). The most common type of quorum sensing genes among multidrug-resistant isolates were related to rhlR and lasI genes with 94.3%. Furthermore, rhlI, rhlR, and lasI genes were positive for all extensively drug-resistant isolates. However, the lasR gene had the lowest frequency among both multidrug-resistant (83.0%) and extensively drug-resistant (90.6%) isolates. Moreover, rhlR (94.7%) and lasR (81.7%) genes had the highest and lowest prevalence among biofilm-forming isolates, respectively.

CONCLUSION

Our findings disclosed the significantly high prevalence of drug resistance among P. aeruginosa isolates. Also, the quorum sensing system had a significant correlation with biofilm formation and drug resistance, indicating the essential role of this system in the emergence of nosocomial infections caused by P. aeruginosa.

Is Short-Course Antibiotic Therapy Suitable for Pseudomonas aeruginosa Bloodstream Infections in Onco-hematology Patients With Febrile Neutropenia? Results of a Multi-institutional Analysis

BACKGROUND

Several studies have suggested that short-course antibiotic therapy was effective in Pseudomonas aeruginosa (PA) bloodstream infections (BSI) in immunocompetent patients. But similar studies in patients with hematological malignancies were rare.

METHODS

This cohort study included onco-hematology patients at 2 hematology centers in China. Inverse probability of treatment weighting was used to balance the confounding factors. Multivariate regression model was used to evaluate the effect of short-course antibiotic therapy on clinical outcomes.

RESULTS

In total, 434 patients met eligibility criteria (short-course, 7-11 days, n = 229; prolonged, 12-21 days, n = 205). In the weighted cohort, the univariate and multivariate analysis indicated that short course antibiotic therapy had similar outcomes to the prolonged course. The recurrent PA infection at any site or mortality within 30 days of completing therapy occurred in 8 (3.9%) patients in the short-course group and in 10 (4.9%) in the prolonged-course group (P = .979). The recurrent infection within 90 days occurred in 20 (9.8%) patients in the short-course group and in 13 (6.3%) patients in the prolonged-course group (P = .139), and the recurrent fever within 7 days occurred in 17 (8.3%) patients in the short-course group and in 15 (7.4%) in the prolonged-course group (P = .957). On average, patients who received short-course antibiotic therapy spent 3.3 fewer days in the hospital (P < .001).

CONCLUSIONS

In the study, short-course therapy was non-inferior to prolonged-course therapy in terms of clinical outcomes. However, due to its biases and limitations, further prospective randomized controlled trials are needed to generalize our findings.

High Rate of Inappropriate Antibiotics in Patients with Hematologic Malignancies and Pseudomonas aeruginosa Bacteremia following International Guideline Recommendations

Optimal coverage of Pseudomonas aeruginosa is challenging in febrile neutropenic patients due to a progressive increase in antibiotic resistance worldwide. We aimed to detail current rates of resistance to antibiotics recommended by international guidelines for P. aeruginosa isolated from bloodstream infections (BSI) in patients with hematologic malignancies. Secondarily, we aimed to describe how many patients received inappropriate empirical antibiotic treatment (IEAT) and its impact on mortality. We conducted a retrospective, multicenter cohort study of the last 20 BSI episodes caused by P. aeruginosa in patients with hematologic malignancies from across 14 university hospitals in Spain. Of the 280 patients with hematologic malignancies and BSI caused by P. aeruginosa, 101 (36%) had strains resistant to at least one of the β-lactam antibiotics recommended in international guidelines, namely, cefepime, piperacillin-tazobactam, and meropenem. Additionally, 21.1% and 11.4% of the strains met criteria for MDR and XDR P. aeruginosa, respectively. Even if international guidelines were followed in most cases, 47 (16.8%) patients received IEAT and 66 (23.6%) received inappropriate β-lactam empirical antibiotic treatment. Thirty-day mortality was 27.1%. In the multivariate analysis, pulmonary source (OR 2.22, 95% CI 1.14 to 4.34) and IEAT (OR 2.67, 95% CI 1.37 to 5.23) were factors independently associated with increased mortality. We concluded that P. aeruginosa-causing BSI in patients with hematologic malignancies is commonly resistant to antibiotics recommended in international guidelines, which is associated with frequent IEAT and higher mortality. New therapeutic strategies are needed. IMPORTANCE Bloodstream infection (BSI) caused by P. aeruginosa is related with an elevated morbidity and mortality in neutropenic patients. For this reason, optimal antipseudomonal coverage has been the basis of all historical recommendations in the empirical treatment of febrile neutropenia. However, in recent years the emergence of multiple types of antibiotic resistances has posed a challenge in treating infections caused by this microorganism. In our study we postulated that P. aeruginosa-causing BSI in patients with hematologic malignancies is commonly resistant to antibiotics recommended in international guidelines. This observation is associated with frequent IEAT and increased mortality. Consequently, there is a need for a new therapeutic strategy.

Microbiology and Clinical Outcome of Bloodstream Infections in Patients After Hematopoietic Stem Cell Transplantation

Purpose

Patients after hematopoietic stem cell transplantation (HSCT) are often followed by bloodstream infections (BSIs). BSI is an important cause of non-relapse mortality (NRM) in HSCT patients.

Methods

We conducted a retrospective cohort study of patients (aged >14 years) who underwent HSCT at our hospital from 2017 to 2021. Population characteristics, BSI microbiology, resistance to common antibiotics, and 30-day all-cause mortality were analyzed.

Results

Of 3054 patients, 169 (5.5%) had BSIs after HSCT. Male, not in complete remission at transplantation and longer duration of neutropenia were risk factors for the development of BSI after HSCT. These BSIs were Gram-negative bacterial (n=123, 69.49%), Gram-positive bacterial (n=27, 15.25%), fungal (n=11, 6.36%), and polymicrobial (n=16, 9.25%). Among the Gram-negative bacteria, the proportions of isolates resistant to ceftazidime, cefepime, and piperacillin-tazobactam were similar (72.93%, 74.80%, and 77.42%, respectively). The overall drug resistance rates of amikacin and imipenem were 16.13% and 43.90%, respectively. Staphylococcus isolates were methicillin-resistant. In Enterococcus isolates, the penicillin resistance rate was 84.62%. Eleven isolates of Candida tropicalis were resistant to fluconazole and were sensitive to amphotericin B and flucytosine. The 30-day all-cause mortality rate of the 169 patients with BSIs was 8.88%. The 30-day all-cause mortality of patients with Gram-negative bacterial BSIs was 7.32%, 25.00% for polymicrobial BSIs, and 36.36% for fungal BSIs. The 30-day all-cause mortality of patients with fungal BSIs was significantly higher than that of patients with Gram-negative (P=0.0023) and Gram-positive bacteria (P=0.0023). Fungal BSI and non-Hodgkin's lymphoma (NHL) were associated with higher 30-day mortality.

Conclusion

Our study reveals the microbiological characteristics and 30-day all-cause mortality in patients with bloodstream infections after HSCT. Our data provides strong support for empirical antimicrobial therapy and infection prevention strategies for patients with BSIs after HSCT.

Clinical characteristics of bloodstream infections in adult patients with solid tumours and a nomogram for mortality prediction: a 5-year case-controlled retrospective study in a tertiary-level hospital

Background

Bloodstream infections (BSIs) are one of the leading causes of death in cancer patients. Nevertheless, the risk factors of BSIs in solid tumors have rarely been ascertained adequately.

Methods

We conducted a single-center case-controlled retrospective study from 2017 to 2021 among adults with solid tumors in a tertiary-level hospital. The BSIs and control group were matched by the propensity score matching method. We found independent risk factors of occurrence and death of BSIs using univariate and multivariate regression analysis. Additionally, a nomogram was constructed to predict the risk of mortality in BSIs.

Results

Of 602 patients with solid tumors in the study period, 186 had BSIs and 416 had non-BSIs. The incidence of BSIs was 2.0/1,000 admissions (206/102,704), and the 30-day mortality rate was 18.8% (35/186). Compared to the control group, the BSIs had longer hospital stays (24.5 days vs. 20.0 days), and higher frequency complicating with organ failure (10.5% vs. 2.4%), nephropathy (19.6% vs. 3.8%), comorbidities≥3 (35.5% vs. 20.0%), and liver-biliary-pancreatic infections (15.6% vs. 5.3%) (all P<0.001). Among the 186 patients with BSIs, 35 died within 30 days after BSIs. Gram-negative bacteria were the most frequent microorganisms (124/192, 64.6%). Liver cancer, organ failure, a high level of lactate dehydrogenase and septic shock were the independent hazardous factors for death of BSIs. What's more, a nomogram was constructed to predict the 30-day survival rate of BSIs, which was proved to have good accuracy (AUC: 0.854; 95% confidence interval: 0.785~0923) and consistency.

Conclusion

Being aware of the risk factors of BSIs redounds to take preventive measures to reduce the incidence and death of BSIs.

Microbiology and prognostic prediction model of bloodstream infection in patients with hematological malignancies

Background

In recent years, with the continuous development of treatments for hematological malignancies (HMs), the remission and survival rates of patients with HMs have been significantly improved. However, because of severe immunosuppression and long-term recurrent neutropenia during treatment, the incidence and mortality of bloodstream infection (BSI) were all high in patients with HMs. Therefore, we analyzed pathogens' distribution and drug-resistance patterns and developed a nomogram for predicting 30-day mortality in patients with BSIs among HMs.

Methods

In this retrospective study, 362 patients with positive blood cultures in HMs were included from June 2015 to June 2020 at West China Hospital of Sichuan University. They were randomly divided into the training cohort (n = 253) and the validation cohort (n = 109) by 7:3. A nomogram for predicting 30-day mortality after BSIs in patients with HMs was established based on the results of univariate and multivariate logistic regression. C-index, calibration plots, and decision curve analysis were used to evaluate the nomogram.

Results

Among 362 patients with BSIs in HMs, the most common HM was acute myeloid leukemia (48.1%), and the most common pathogen of BSI was gram-negative bacteria (70.4%). The final nomogram included the septic shock, relapsed/refractory HM, albumin <30g/l, platelets <30×10⁹/l before BSI, and inappropriate empiric antibiotic treatment. In the training and validation cohorts, the C-indexes (0.870 and 0.825) and the calibration plots indicated that the nomogram had a good performance. The decision curves in both cohorts showed that the nomogram model for predicting 30-day mortality after BSI was more beneficial than all patients with BSIs or none with BSIs.

Conclusion

In our study, gram-negative bacterial BSIs were predominant in patients with HMs. We developed and validated a nomogram with good predictive ability to help clinicians evaluate the prognosis of patients.

Short Course of Antibiotic Therapy for Gram-Negative Bacilli Bacteremia in Patients with Cancer and Hematopoietic Stem Cell Transplantation: Less Is Possible

Data about short courses of antibiotic therapy for Gram-negative bacilli (GNB) bacteremia in immunosuppressed patients are limited. This is a prospective observational study performed on adult patients with cancer and hematopoietic stem cell transplant (HSCT) who developed GNB bacteremia and received appropriate empirical antibiotic therapy (EAT), had a clinical response within 7 days and survived 48 h after the end of therapy. They received antibiotic therapy in the range of 7-15 days and were divided into short course, with a median of 7 days (SC), or long course, with a median of 14 days (LC). Seventy-four patients were included (SC: 36 and LC: 38). No differences were observed in baseline characteristics or in the presence of neutropenia: 58.3% vs. 60.5% (p = 0.84). Clinical presentation and microbiological characteristics were similar in SC and LC, respectively: clinical source of bacteremia 72.2% vs. 76.3% (p = 0.68); shock 2.8% vs. 10.5% (p = 0.35) and multidrug-resistant GNB 27.8% vs. 21.1% (p = 0.50). Overall, mortality was 2.8% vs. 7.9% (p = 0.61), and bacteremia relapse was 2.8% vs. 0 (p = 0.30). The length of hospitalization since bacteremia was 7 days (interquartile range (IQR), 6-15) for SC and 12 days (IQR, 7-19) (p = 0.021) for LC. In the case of patients with cancer or HSCT and GNB bacteremia who receive appropriate EAT with clinical response, 7 days of antibiotic therapy might be adequate.

Bacterial Infections and Cancer: Exploring This Association And Its Implications for Cancer Patients

Bacterial infections are common in the etiology of human diseases owing to the ubiquity of bacteria. Such infections promote the development of periodontal disease, bacterial pneumonia, typhoid, acute gastroenteritis, and diarrhea in susceptible hosts. These diseases may be resolved using antibiotics/antimicrobial therapy in some hosts. However, other hosts may be unable to eliminate the bacteria, allowing them to persist for long durations and significantly increasing the carrier's risk of developing cancer over time. Indeed, infectious pathogens are modifiable cancer risk factors, and through this comprehensive review, we highlight the complex relationship between bacterial infections and the development of several cancer types. For this review, searches were performed on the PubMed, Embase, and Web of Science databases encompassing the entirety of 2022. Based on our investigation, we found several critical associations, of which some are causative: Porphyromonas gingivalis and Fusobacterium nucleatum are associated with periodontal disease, Salmonella spp., Clostridium perfringens, Escherichia coli, Campylobacter spp., and Shigella are associated with gastroenteritis. Helicobacter pylori infection is implicated in the etiology of gastric cancer, and persistent Chlamydia infections present a risk factor for the development of cervical carcinoma, especially in patients with the human papillomavirus (HPV) coinfection. Salmonella typhi infections are linked with gallbladder cancer, and Chlamydia pneumoniae infection is implicated in lung cancer, etc. This knowledge helps identify the adaptation strategies used by bacteria to evade antibiotic/antimicrobial therapy. The article also sheds light on the role of antibiotics in cancer treatment, the consequences of their use, and strategies for limiting antibiotic resistance. Finally, the dual role of bacteria in cancer development as well as in cancer therapy is briefly discussed, as this is an area that may help to facilitate the development of novel microbe-based therapeutics as a means of securing improved outcomes.