Gram-negative bloodstream infections and sepsis: risk factors, screening tools and surveillance

Blood neutrophil to lymphocyte ratio is associated with 90-day mortality and 60-day readmission in Gram negative bacteremia: a multi-center cohort study

INTRODUCTION

The Neutrophil-Lymphocyte Ratio (NLR) in blood has demonstrated its capability to predict bacteremia in emergency departments, and its association with mortality has been established in patients with sepsis in intensive care units. However, its potential concerning mortality and readmission in patients with Gram-negative bacteremia (GNB) is unexplored.

METHODS

This retrospective cohort study included patients with GNB between 2018 and 2022 from six hospitals in the Capital Region of Denmark. Patients who were immunosuppressed or had missing NLR values on the day of blood culture were excluded. Logistic regression models were used to analyze the association between NLR levels and 90-day all-cause mortality, while the logit link interpretation of the cumulative incidence function was used to assess the association between NLR levels and 60-day readmission. Associations were quantified as odds ratios (OR) with corresponding 95% confidence intervals (CI).

RESULTS

The study included 1763 patients with a median age was 76.8 years and 51.3% were female. The median NLR was 17.3 and 15.8% of patients had a quick sequential organ failure assessment score of two or three. Urinary tract infection (UTI) was the most frequent focus and Escherichia coli the most frequent pathogen. Statistically significant differences in median NLR were found by age group and pathogen, and for patients with or without hypertension, liver disease, chronic obstructive pulmonary disease, dementia, and alcohol abuse. 378 patients (21.4%) died before 90 days. 526 (29.8%) patients were readmitted to the hospital within 60 days. For each doubling of the NLR, the OR for all-cause 90-day mortality was 1.15 (95% CI, 1.04-1.27) and 1.12 (95% CI, 1.02-1.24) for 60-day readmission. Analysis of subgroups did not show statistically significant differences between groups in relation to the association between NLR and mortality. The discriminatory ability of NLR for mortality was limited and comparable to blood neutrophil or lymphocyte count, producing receiver operating characteristic curves with an area under the curve of 0.59 (95% CI, 0.56-0.63), 0.60 (95% CI, 0.56-0.65) and 0.53 (95% CI, 0.49-0.56), respectively.

CONCLUSION

Blood neutrophil-lymphocyte ratio was associated with 90-day all-cause mortality and 60-day readmission in patients with GNB. However, the ratio has limited ability in predicting mortality or readmission.

Emulating a Target Trial of Shorter Compared to Longer Course of Antibiotic Therapy for Gram-Negative Bacteremia

BACKGROUND

Despite the availability of antimicrobial therapies, gram-negative bacteremia remains a significant cause of morbidity and mortality on a global level. Recent randomized controlled trials support shorter antibiotic treatment duration for individuals with uncomplicated gram-negative bacteremia. The target trial framework using the cloning approach utilizes real-world data but eliminates the issue of immortal time bias seen in observational studies by emulating the analysis of randomized trials with full adherence.

METHOD

A hypothetical target trial allocating individuals with gram-negative bacteremia to either short antibiotic treatment duration (5-7 days) or longer antibiotic treatment duration (8-14 days) was specified and emulated using the cloning, censoring, and weighting approach. The primary outcome was 90-day all-cause mortality. Secondary outcome was a composite endpoint of clinical and microbiological relapse. The emulated trial included individuals from four hospitals in Copenhagen from 2018 through 2021.

RESULTS

In sum, 1040 individuals were included. The median age of the cohort was 76 years, the majority were male (54%), had community-acquired gram-negative bacteremia (86%), urinary tract infection as the source of the infection (78%), and Escherichia coli as the pathogen of the infection (73%). The adjusted 90-day risk difference in all-cause mortality was 1.3% (95% confidence interval [CI]: -.7, 3.3), and the risk ratio was 1.12 (95% CI: .89, 1.37). The adjusted 90-day risk difference in relapse was 0.7% (95% CI: -2.3, 3.8), and the risk ratio was 1.07 (95% CI: .71, 1.45).

CONCLUSIONS

We found comparative outcomes for shorter treatment duration compared to longer treatment duration in patients with gram-negative bacteremia.

Gram negative bacteria related urinary tract infections: spectrum of antimicrobial resistance over 9 years in a University tertiary referral Hospital

Objective

Overuse of antibiotics has led to an increase in antimicrobial resistance (AMR) worldwide, with a negative impact on the healthcare system and the patients. In this context, our study aims to assess the current AMR patterns of urinary tract infections (UTIs) associated to Gram-negative bacteria. Thus, we provide useful information for doctors dealing with prophylactic and therapeutic empiric therapies.

Materials and methods

We retrospectively analysed more than 650,000 urine cultures collected in the Microbiology Department of a referral University Hospital of Southern England from January 2014 to December 2022.

Results

AMR spectra for 164,059 Gram-negative associated (UTIs) were analysed. The lowest percentage of resistance was found for Amikacin (2.30%), Gentamicin (5.89%) and Co-Amoxiclav (10.49%). Over a 9-year time, there was no significant change in resistance to Amikacin (2.04% in 2014 compared to 2.18% in 2022; p = 0.602) and to Fosfomycin (11.50% in 2014 versus 16.65% in 2022; p = 0.577). Overall, the trend of AMR significantly rose for Cefalexin (17.96-18.42%; p < 0.0001), Co-amoxiclav (9.46-12.69%; p < 0.0001), Nitrofurantoin (10.20-14.18%; p < 0.0001) and Piperacillin/Tazobactam (14.52-18.96%; p < 0.0001). Gram-negative resistance spectrum towards Ciprofloxacin (11.83-9.01%; p < 0.0001), Gentamicin (6.29-5.26%; p < 0.0001), Pivmecillinam (26.88-11.02%; p < 0.0001), Trimethoprim (36.72-29.23%; p < 0.0001) and Ampicillin/Amoxicillin (65.20-57.99%; p < 0.0001) significantly decreased.

Conclusion

Despite the application of national and international guidelines for prophylaxis and treatment of UTIs, the spectrum of resistance for the most common antibiotics is still changing. Clinicians in primary and secondary care must keep that in mind when prescribing antibiotics for suspected UTI and sepsis associated with Gram-negative infections Up-to-date therapeutic strategies can help implement treatment of UTI, reducing selection of multi-resistant pathogens and providing more accurate care for patients. Future studies will be required to help clinicians and keep the guidelines updated.

Predictive value of risk factors for prognosis of patients with sepsis in intensive care unit

Sepsis has emerged as a major global public health concern due to its elevated mortality and high cost of care. This study aimed to evaluate the risk factors associated with the mortality of sepsis patients in the Intensive Care Unit (ICU), and to intervene in the early stages of sepsis in order to improve patient outcomes and reduce mortality. From January 1st, 2021 to December 31st, 2021, Longhua Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Huashan Hospital Affiliated to Fudan University, and The Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine were designated as sentinel hospitals, and sepsis patients in their respective ICU and Emergency ICU were selected as research subjects, and divided into survivors and non-survivors according to their discharge outcomes. The mortality risk of sepsis patients was subsequently analyzed by logistic regression. A total of 176 patients with sepsis were included, of which 130 (73.9%) were survivors and 46 (26.1%) were non-survivors. Factors identified as having an impact on death among sepsis patients included female [Odds Ratio (OR) = 5.135, 95% confidence interval (CI): 1.709, 15.427, P = .004)], cardiovascular disease (OR = 6.272, 95% CI: 1.828, 21.518, P = .004), cerebrovascular disease (OR = 3.133, 95% CI: 1.093, 8.981, P = .034), pulmonary infections (OR = 6.700, 95% CI: 1.744, 25.748, P = .006), use of vasopressors (OR = 34.085, 95% CI: 10.452, 111.155, P < .001), WBC < 3.5 × 109/L (OR = 9.752, 95% CI: 1.386, 68.620, P = .022), ALT < 7 U/L (OR = 7.672, 95% CI: 1.263, 46.594, P = .027), ALT > 40 U/L (OR = 3.343, 95% CI: 1.097, 10.185, P = .034). Gender, cardiovascular disease, cerebrovascular disease, pulmonary infections, the use of vasopressors, WBC, and ALT are important factors in evaluating the prognostic outcome of sepsis patients in the ICU. This suggests that medical professionals should recognize them expeditiously and implement aggressive treatment tactics to diminish the mortality rate and improve outcomes.

Risk Factors for a Hospital-Acquired Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infection: A Five-Year Retrospective Study

Purpose

This study aimed to describe trends in Klebsiella pneumoniae (KP) resistance in bloodstream infections (BSI) and to identify risk factors for a hospital-acquired carbapenem-resistant Klebsiella pneumoniae (CRKP) BSI and 28-day mortality from a hospital-acquired KP BSI.

Patients and Methods

We recorded the results of antimicrobial susceptibility testing of 396 KP-positive blood cultures from January 2016 to December 2020. A total of 277 patients with a KP BSI were included in this study, of which 171 had a hospital-acquired infection and 84 had a hospital-acquired CRKP BSI. Multivariate logistic regression analysis was used to identify risk factors for a hospital-acquired CRKP BSI and 28-day mortality from a hospital-acquired KP BSI.

Results

The proportion of hospital-acquired infections among KP BSI patients increased from 53.1% in 2016 to 72.8% in 2020. The detection rate of CRKP among KP BSI patients increased from 18.8% in 2016 to 37.7% in 2020. Multivariate logistic regression showed that β-lactam/β-lactamase inhibitor combinations (BLBLIs) exposure (P  = 0.022, OR 2.863), carbapenems exposure (P  = 0.007, OR 3.831) and solid organ transplantation (P   <0.001, OR 19.454) were independent risk factors for a hospital-acquired CRKP BSI. Risk factors for a 28-day mortality from hospital-acquired KP BSI were CRKP BSI (P  =0.009, OR 5.562), septic shock (P  =0.002, OR 4.862), mechanical ventilation>96 hours (P =0.020, OR 8.765), and platelet counts <100×10⁹/L (P  =0.003, OR 4.464).

Conclusion

The incidence of hospital-acquired KP BSI continues to rise and the proportion of CRKP BSI is also increasing. We believe that the use of the BLBLIs needs to be carefully evaluated in hospital-acquired infection. Hospital-acquired KP BSI Patients with CRKP BSI, septic shock, mechanical ventilation and deficiency of platelets are more likely to have a poor prognosis.

Divergent Sepsis Pathophysiology in Older Adults

Significance: Both incidence and mortality rates of sepsis significantly increase with advanced age, and the majority of sepsis patients are late middle-aged or older. With the proportion of older adults rapidly increasing in developed countries, age-dependent sepsis vulnerability is an urgent medical issue. Due to an increasing life expectancy, postsepsis complications and health care costs are expected to increase as well. Recent Advances: Older patients suffer from higher sepsis incidence and mortality rates, likely resulting from frequent comorbidities, increased coagulation, dysgylcemia, and altered immune responses. Critical Issues: Despite a large number of ongoing clinical and basic research studies, there is currently no effective therapeutic strategy targeting older patients with severe sepsis. The disparity between clinical and basic studies is a problem, and this is largely due to the use of animal models lacking clinical relevance. Although the majority of sepsis cases occur in older adults, most laboratory animals used for sepsis research are very young. Further, despite the wide use of combination fluid and antibiotic treatment in intensive care unit (ICU) patients, most animal research does not include such treatment. Future Directions: Because sepsis is a systemic disease with multiple organ dysfunction, combined therapy approaches, not those targeting single pathways or single organs, are essential. As for preclinical research, it is critical to confirm new findings using aged animal models with clinically relevant ICU-like medical treatments. Antioxid. Redox Signal. 35, 1358-1375.

Risk factors for nosocomial bloodstream infections in COVID-19 affected patients: protocol for a case-control study

BACKGROUND

Nosocomial bloodstream infection (nBSI) is an important clinical concern among COVID-19 hospitalised patients. It can cause sepsis and septic shock leading to high morbidity, mortality, and the emergence of antibiotic resistance. The aim of this case-control study is to identify the risk factors associated with the nBSI development in COVID-19 hospitalised patients and its incidence.

METHODS AND ANALYSIS

A retrospective case-control study will be performed. Cases will include nBSI episodes of adult patients (≥18 years) admitted to Hospital Universitari Germans Trias i Pujol, Barcelona, Spain, from April to December 2020 with a diagnosis of SARS-CoV-2 pneumonia. Patients transferred from other hospitals will be excluded. Controls will include hospitalisation episodes of COVID-19 patients without nBSI. We will recruit a minimum of 74 nBSI episodes (cases) and 74 controls (according to sample size calculation). We will collect data on sociodemographics, clinical status at admission, hospital admission, in-hospital mortality, and exposure data (use of antivirals, glucocorticoids or immunomodulatory agents, length of hospitalisation, and use of medical devices such as intravenous catheters). A bivariate and a subsequent multivariate regression analysis will be performed to assess the independent effect of the associated risk factors after adjusting for confounders. The nBSI incidence rate will be estimated according to the number of nBSI episodes in admitted COVID-19 patients among the total person-month of follow-up.

ETHICS AND DISSEMINATION

The protocol of this study was approved by the Ethical Committee for Drug Investigation of the Hospital Universitari Germans Trias i Pujol. The results of this case-control study will be published in a peer reviewed journal.