Episodes Of Bloodstream Infection Research Articles

25 years of experience on the management of enterococcal infective endocarditis an observational study.

As they are effective and well tolerated, aminopenicillins are still the cornerstone for the treatment of enterococcal infections. Current treatment guidelines for infective endocarditis (IE) recommend combination treatments, which carry a higher risk of adverse effects and are based on limited in vitro and experimental data. The aim of this study was therefore to evaluate the treatments of enterococcal IE in real-life practice. A total of 4121 episodes of enterococcal bloodstream infections, occurring between 1994 and 2019, were screened for the evidence of IE. Baseline characteristics, risk factors for complicated infections and treatment information were assessed and analyzed using Cox regression analysis. Overall, 80 (3.9%) IE episodes were identified of which 78 were included in the final analysis. Treatment regimens in our cohort comprised aminopenicillin-monotherapy (n = 20), teicoplanin-monotherapy (n = 26), other monotherapies (OMT) (n = 8), as well as combinations of ampicillin plus daptomycin (n = 8), ampicillin plus gentamicin (n = 4) or other combinations (n = 9). Overall mortality at 28-days was low (9 of 75) and increased to (19 of 75) after 6-months. Frequency of moderate to severe valve regurgitation (p = 0.89), or signs of uncontrolled infection (p = 0.5) and vegetation size ≥ 10mm (p = 0.11) were similar in the treatment groups. None of the treatment groups was associated with increased hazard for IE-related mortality. This retrospective study complements previous evidence, demonstrating that monotherapy regimens may be a suitable and effective option for the treatment of IE and supports the need for a prospective evaluation of aminopenicillin-monotherapy for initial and subsequent therapy in these patients.

Impact of discontinuing routine fluoroquinolone prophylaxis in neutropenic allogeneic haematopoietic stem cell transplant recipients: an observational study.

Uncertainty exists as to the role of fluoroquinolone (FQ) prophylaxis for patients undergoing allogeneic haematopoietic stem cell transplantation (HSCT) in the era of rising antibiotic resistance. We aimed to evaluate rates of bloodstream infections (BSI), resistance patterns and outcomes of patients after discontinuing routine FQ prophylaxis administration. All adult recipients of first HSCT from 2017 to 2020 were retrospectively included and classified according to time of HSCT as FQ group (HSCT January 2017-December 2018) or no FQ group (January 2019-December 2020). The primary outcome was Gram-negative (GN) BSI from day -7 to 30 days post-HSCT. The independent association between the study period and BSI was assessed using survival analysis, and adjusting for confounders. We included 254 patients, 130 (51%) and 124 (49%) in the FQ and no FQ groups, respectively. Compared to the FQ group, no FQ had significantly more GN BSI (21% versus 33%, P = 0.027) and the median time to first GN BSI was significantly shorter [4 (IQR 1-8) days versus 6 (1-10) days, P = 0.009]. Following adjustment, FQ prophylaxis remained associated with lower hazard for GN BSI (hazard ratio 0.57, 95% CI 0.34-0.93). Eighty-two GN BSI episodes had FQ susceptibility testing. More GN BSI episodes were FQ resistant in the FQ group (68.9% versus 41.6%, P = 0.021). No significant difference was found for 30-day mortality, time to first febrile neutropenia and time to first broad-spectrum antibiotics between the groups (P was not significant). FQ prophylaxis is associated with fewer GN BSI in the early post-HSCT period even in high FQ resistance settings, with FQ resistance rates reaching >60% following prophylaxis.

Bloodstream infections in a Brazilian Pediatric Tertiary Oncology Hospital: 30-month analysis regarding the classification of the infection, distribution of microorganisms and their resistance profile

Abstract Background Infections are a major cause of morbidity and mortality in pediatric oncology patients during their treatment. Bloodstream infections are the main site of infection in these patients. Bacteremia in these patients can be secondary to a primary infectious focus, result from central line associated bloodstream infections (CLABSIs) or mucosal barrier injury laboratory-confirmed bloodstream infection (MBI-LCBI). Methods Descriptive study of bloodstream infections in pediatric patients undergoing oncological treatment and hematopoietic stem cell transplantation in a tertiary pediatric oncology hospital in Brazil from January 1st, 2021 to June 30th, 2023. Infections were classified according to the Centers for Disease Control and Prevention/ National Healthcare Safety Network (CDC/NHSN) criteria into CLABSIs, MBI-LCBIs and secondary bloodstream infections. Among the bloodstream infections that met CDC/NHSN criteria for CLABSI, were analyzed separately those who also met the criteria of catheter-related bloodstream infection (CRBSI) according to Infectious Diseases Society of America (IDSA). Results During this period were diagnosed 335 episodes of bloodstream infection (123 episodes in 2021, 150 in 2022 and 62 episodes in the first 6 months of 2023). There were 378 microorganisms isolated. These infections were classified into: 35% CLABSIs, 27% MBI-LCBIs, 23% CRBSIs, and 15% secondary bloodstream infections. Among the CLABSIs, the most common microorganisms were non-fermenting gram negative bacilli (NFGNB) 38%, enterobacteriaceae 35% and coagulase-negative staphylococcus (CoNS) 11%. Between CRBSIs, there were 31% enterobacteriaceae, 22% CoNS and 19% NFGNB. Among the MBI-LCBIs there were 66% enterobacteriaceae and 23% group viridans streptococci (VGS). Streptococcus pneumoniae (33%) was the most common microorganism in secondary infections followed by Staphylococcus aureus (17%). Assessing all infections together, the main enterobacteriaceae were Klebsiella spp. (40%) and only 50% of them were sensitive to cefepime while 10% were carbapenems resistant. Among NFGNB, 13% of Pseudomonas spp. and 5% of Acinetobacter spp. were carbapenems resistant. Between the gram-positive bacteria, 77% of the S. aureus were methicillin sensitive, the same percentage of the VGS were sensitive to cefepime. Conclusion Among bloodstream infections, there were a predominance of CLABSI followed by MBI-LCBIs. Antimicrobial resistance between gram-positive bacteria, is of little concern in our institution. In the case of gram-negative bacteria, resistance to cefepime is becoming worrying among enterobacteriaceae.

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

Background and objectiveInappropriate initial antimicrobial therapy has been associated with high mortality in patients with gram-negative bacilli bloodstream infections during febrile neutropenia following chemotherapy for hematological malignancies. The aim of this study is to determine this association in our hospital. MethodsA single center, retrospective, cohort study of bloodstream infection due to gram-negative bacilli and febrile neutropenia was conducted. Clinical characteristics, microbiological etiology, antimicrobial resistance profile, empirical and targeted antibiotic therapy, intensive care unit admission, persistent bacteremia and mortality were analyzed. ResultsOf the 171 episodes of bloodstream infection due to gram-negative bacilli, empirical antimicrobial therapy was inappropriate in 43 episodes (25.1 %). There was a significant difference in mortality at 7 and 30 days between patients who received appropriate versus inappropriate empirical treatment (4.6 % versus 13.9 %, p = 0.04; 15.6 % versus 32.5 %, p = 0.016). Inappropriate empirical treatment (RR, 2.97 [95 % CI, 1.01–8.74]), shock at the time of febrile neutropenia diagnosis (RR, 6.5 [95 % CI, 1.83–23.05]) carbapenem-resistant microorganism (RR, 3.73 [95 % CI, 1.14–12.24]) and persistent bacteremia (RR, 84.6 [95 % CI, 11.3–629.4]) were associated with an increased mortality at 7 and 30 days. In the multivariate analysis, shock (RR, 4.85 [95 % CI, 2.10–11.65]) and persistent bacteremia was independently associated with increased 30-day mortality, but inappropriate empirical antimicrobial therapy was not an independent prognostic determinant (RR, 1.66 [0.53–4.82]). ConclusionShock at the time of febrile neutropenia diagnosis contributes to mortality in patients with gram-negative bacilli bloodstream infection, in this scenario, appropriate empirical antimicrobial therapy should be encouraged.

Carbapenem resistance in Enterobacterales: Predicting clinical outcomes in bloodstream infections

PurposeCarbapenem-resistant Enterobacterales (CRE) are a global concern due to their high mortality rates and limited therapeutics. CRE-caused bloodstream infections (BSIs) are challenging to manage, especially in healthcare settings. This study aimed to investigate the predictors of mortality in BSI patients caused by CRE. MethodsA single center prospective study to examine the characteristics of BSI caused by CRE in a large academic hospital over 15 months. The main outcomes were microbiological characteristics and clinical outcomes of patients at 28 days based on a step-wise regression analysis. ResultsA total of 76 episodes of BSI due to CRE were included. The study found that the most common type of carbapenemase was OXA-48 (69.7 %, n = 53), followed by the co-existence of OXA-48 and MBL (26.3 %, n = 20), with Klebsiella pneumoniae being the most common (90 %, n = 69). Patients with OXA-48-BSI were more likely to have a urinary source of infection, while patients with MBL-BSI were more likely to have a non-urinary source of infection. All cases (100 %) had medical devices. Around 30.3 % of patients received effective empirical treatment, while 61.8 % received adequate therapy at 48 h. The overall mortality rate was 42.1 % (n = 32), and the main predictors of mortality in this study were the presence of sepsis and inadequate initial therapy, while age >65 predicted mortality in the linear regression but not the stepwise regression model. ConclusionCRE-BSIs are a serious health threat. The study highlights the need for preventive strategies focused on high-risk patients and proper device management to reduce BSI.

Multi-chamber parenteral nutrition (PN) bags are safe and cost-effective in replacing compounded PN regimens in hospitalised patients

Background & AimsThere is varied international practice in the use of ready-made multi-chamber bags (MCBs) and compounded parenteral nutrition (PN). Recent national aseptic pharmacy capacity limitations have restricted compounded PN production so we aimed to explore outcomes associated with the increased use of MCB vs compounded regimens during a period of change in PN supplies. MethodsThis was a point prevalence study conducted over two time periods, Period 1: 01.01.2022 – 31.03.2022 and Period 2: 01.10.2022 – 31.12.2022. Data were collected on PN regimen, outcomes, cost and aseptic time required to prepare PN bags. Results263 patients were included: 132 in Period 1 and 131 in Period 2. Overall, 2263 PN bags were utilised; 1179 in Period 1 and 1084 in Period 2. In Period 1, of all utilised bags, 138 (11.7%) were compounded PN, 356 (30.2%) supplemented MCBs and 685 (58.1%) manipulated MCBs whereas in Period 2, 0 were compounded PN, 546 (50.3%) supplemented MCBs and 538 (49.6%) manipulated MCBs. There were no significant differences in the proportion of patients with deranged blood tests between the study periods. In both periods there were only two episodes of catheter-related blood stream infection. The total cost saved in Period 2 compared to Period 1 was £20,684 and total aseptic staff time saved was 191 hours. ConclusionWider use of in-hospital MCB PN regimens could lead to a reduction in the need for compounded PN produced by aseptic pharmacy facilities, saving costs while maintaining good patient outcomes.

Early Antibiotic De-escalation in Patients With Severe Infections Due to Bloodstream Infection by Enterobacterales: A Post Hoc Analysis of a Prospective Multicentre Cohort

Data about antibiotic de-escalation in sepsis associated with the bloodstream and caused by Enterobacterales are scarce. The objectives of this study are to identify factors associated with early de-escalation and to analyse the impact of de-escalation on mortality in patients with Enterobacterales bloodstream infection (BSI) with a Sequential Organ Failure Assessment (SOFA) score ≥ 2. A prospective, multicentre cohort study was performed including episodes of BSI due to Enterobacterales and a SOFA score ≥ 2 who were receiving an active antipseudomonal β-lactam; the isolate should be susceptible to at least 1 narrower-spectrum antibiotic. Variables associated with de-escalation were identified using logistic binary regression. The association of de-escalation with 30-day mortality was investigated. Confounding was controlled by calculating a propensity score used as covariate, as matching variable, and for inverse probability treatment weighting. Of the 582 patients included, de-escalation was performed in 311 (53.4%). Neutropenia (adjusted odds ratio [aOR] = 0.37; 95% confidence interval [95% CI] = 0.18-0.75), central venous catheter (aOR = 0.52; 95% CI = 0.32-0.83), and extended-spectrum β-lactamase (ESBL)-producing isolate (aOR = 0.28; 95% CI = 0.17-0.48) were negatively associated with de-escalation, and urinary tract source was positively associated (aOR = 2.27; 95% CI = 1.56-3.33). The 30-day mortality was 6.8% (21 patients) in de-escalated patients and 14.4% (39) in not de-escalated patients (relative risk, 0.63; 95% CI = 0.44-0.89). In multivariate analysis including the propensity score, de-escalation was not associated with mortality (AOR = 0.98; 95% CI = 0.39-2.47) and was protective in the case of urinary or biliary tract source (AOR = 0.31, 95% CI = 0.09-1.06). Matched and inverse probability treatment weighting analysis showed similar results. These results suggest that early de-escalation from antipseudomonal β-lactams is safe in patients with Enterobacterales bacteremia and SOFA ≥ 2.

Outcome of Corynebacterial Bloodstream Infection in Patients With Cardiac Implantable Electronic Devices: A Brief Report and Systematic Review.

Cardiac implantable electronic device infection in the context of corynebacterial bloodstream infection (BSI) remains poorly understood. From 2012 to 2023 at Mayo Clinic, 4 of 12 patients with corynebacterial BSI had cardiac implantable electronic device infection: 1 patient was diagnosed during a relapsing BSI episode. Undefined source, persistent BSI, and the presence of a prosthetic cardiac valve were common characteristics.

Epidemiology of biliary tract-associated bloodstream infections and adequacy of empiric therapy: an Australian population-based study

PurposeAlthough the biliary tract is a common source of invasive infections, the epidemiology of cholangitis- and cholecystitis-associated bloodstream infection (BSI) is not well defined. The objective of this study was to determine the incidence, clinical determinants, microbiology of biliary tract-associated BSI, and predicted adequacy of common empiric therapy regimens.MethodsAll biliary tract-associated BSI in Queensland during 2000–2019 were identified using state-wide data sources. Predicted adequacy of empiric antimicrobial therapy was determined according to microbiological susceptibility data.ResultsThere were 3,698 episodes of biliary tract-associated BSI occurred in 3,433 patients of which 2,147 (58.1%) episodes were due to cholangitis and 1,551 (41.9%) cholecystitis, for age- and sex-standardized incidence rates of 2.7, and 2.0 per 100,000 population, respectively. An increasing incidence of biliary tract-associated BSI was observed over the study that was attributable to an increase in cholangitis cases. There was a significant increased risk for biliary tract-associated BSI observed with advancing age and male sex. Patients with cholangitis were older, more likely to have healthcare associated infection, and have more comorbidities most notably liver disease and malignancies as compared to patients with cholecystitis. The distribution of infecting pathogens was significantly different with polymicrobial aetiologies more commonly observed with cholangitis (18.4% vs. 10.5%; p < 0.001). The combination of ampicillin/gentamicin/metronidazole was predicted to have the overall highest adequacy (96.1%), whereas amoxicillin/clavulanate had the lowest (77.0%). Amoxicillin/clavulanate (75.2% vs. 79.4%, p:0.03) and ceftriaxone/metronidazole (83.4% vs. 89.6%; p < 0.001) showed significantly inferior predicted adequacy for cholangitis as compared to cholecystitis.ConclusionsBloodstream infections related to cholecystitis and cholangitis exhibit different epidemiology, microbiology, and requirements for empiric therapy.

Case validation of bloodstream infections with an antibiotic-resistant organism

Background: Bloodstream infections (BSIs) are an important cause of morbidity and mortality in severely ill patients, contributing to increased length of hospital stay and higher cost of care. Alberta Health Services Infection Prevention and Control (IPC) conducts inpatient surveillance of new episodes of BSIs with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) or carbapenemase-producing organisms (CPO) in 112 acute care facilities. A case-finding process was undertaken to verify the accuracy of BSI data entry. Methods: All positive MRSA, VRE or CPO blood cultures in 2021 were linked to the Inpatient Discharge Abstract Database (DAD) and the National Ambulatory Care Reporting System (NACRS) to identify new cases during acute care admissions. The results were then compared to surveillance records captured by infection control professionals (ICPs). Cases with unmatched culture date and/or encounter date and cases not identified by ICPs were screened by the study team with final decision made by ICPs. Results were analyzed by ARO and by % increase in number of surveillance records. Results: The laboratory linkage identified 286 new cases. Comparing to surveillance records (n = 248) captured by ICPs, 137 (57.3%) had matching collection dates and encounter dates, 85 (35.6%) had close matches on collection dates and encounter dates, 17 (7.1%) records had either matching collection dates or encounter dates, and 1 (0.4%) record did not have any matches on dates. There were 46 records identified in the laboratory data that were not in the surveillance system and 8 records that were in the surveillance system but not matched to the laboratory data. After review, 22 Surveillance records had data entry errors (1 CPO BSI, 20 MRSA BSI, and 1 VRE BSI), and there were 14 BSI records found to be missing (13 MRSA BSI, 1 VRE BSI). This represents a 6% increase in MRSA BSI and a 3% increase in VRE BSI identified in 2021 and no increase in CPO BSI. Conclusions: A laboratory validation to determine if BSIs with an ARO were missed during routine IPC surveillance identified a small proportion of missed bloodstream infections. The most common reason for the miss was admission through the emergency department with multiple blood cultures collected during a single admission. These results will be shared with the Infection Control program to facilitate correct BSI capture.

Predictors and outcomes of multi-drug–resistant gram-negative bacteremia in patients with cancer: A retrospective cohort study at a tertiary cancer center in Oman

ObjectivesThis study aimed to delineate the characteristics and outcomes of gram-negative bacteremia (GNB) in oncology patients; analyze the risk factors for multi-drug–resistant (MDR) GNB; and assess its impact on the recurrence of bloodstream infection (BSI), hospital stay, and 30-day mortality. MethodsData, including demographics, clinical features, common cancers, and microbiologic findings, were collected retrospectively from electronic medical records of patients admitted with solid tumors and BSI episodes between January and December 2022. Fisher's exact tests were used to determine the effect of MDR-GNB on 30-day mortality and BSI recurrence. The Wilcoxon rank-sum test assessed the differences in the length of hospital stay. Logistic regression models identified the risk factors for MDR-GNB. ResultsAmong 1074 patients, 77 episodes of GNB bacteremia occurred in 59 individuals (47% male, median age 57.4 years). Of these, 37 (48%) were MDR-GNB. Carbapenem resistance was noted in 9.1% of GNB episodes. Previous antibiotic use was significantly associated with MDR-GNB (odds ratio 7.82; 95% confidence interval 2.52-24). MDR-GNB was linked to longer hospital stays (median 23 vs 10.5 days, P = 0.003) and higher recurrence rates than non-MDR-GNB (35.13% vs 5.0%, P <0.001). However, 30-day mortality did not significantly differ between the groups (35.14% vs 32.5%, P = 0.81). ConclusionPrevious antibiotic use predicted MDR-GNB in patients with solid tumor. MDR-GNB bacteremia increased the length of hospital stay and risk of recurrence compared with non-MDR-GNB bacteremia.

Impact of an antimicrobial stewardship programme on antibiotic utilization and resistance burden in patients with acute leukaemia: an 11-year longitudinal cohort study using interrupted time-series analysis.

Antimicrobial resistance (AMR), driven by inappropriate and overuse of antibiotics, poses a significant threat, especially to patients with acute leukaemia. To evaluate the impact of antimicrobial stewardship programmes (ASPs) on antibiotic use and analyse temporal changes in bloodstream infections (BSI) caused by AMR organisms. We performed a retrospective, interventional, longitudinal cohort study spanning an 11-year period. ASPs included optimizing antibiotic use, enhancing tracking and reporting systems and delineating leadership and accountability. A segmented regression model of interrupted time series was used to evaluate the trend of antibiotic consumption and BSI with AMR organisms after the interventions. A total of 3296 BSI episodes with 454 419 days of therapy (DOT) from 7754 patients were obtained. ASPs were significantly associated with an immediate reduction [-70.03 DOT/1000 patient-days (PD), P = 0.036] and a decreasing trend (-11.65 DOT/1000 PD per quarter, P < 0.001) in overall antibiotic use. The increasing incidence of BSI with AMR before ASP intervention was notably curbed and revealed a decreasing trend (slope change: -0.06 BSI/1000 PD per quarter, P = 0.002). The decreasing trend was more significant for Enterobacterales: ciprofloxacin-resistant and ESBL-producing isolates showed a slope change of -0.06 BSI/1000 PD and -0.08 BSI/1000 PD per quarter, respectively (all P < 0.05). However, Pseudomonas aeruginosa BSI increased. Multidimensional ASPs effectively reduced both the immediate and trends in overall antibiotic usage even in patients with acute leukaemia. Additionally, there was a notable decrease in the incidence of BSI caused by AMR organisms, particularly among Enterobacterales.

Monitoring and Outcomes of Central Line-Associated Bloodstream Infections in a Tertiary Care Intensive Care Unit.

Background Central line-associated bloodstream infections (CLABSIs) are significant healthcare-associated infections that increase morbidity, mortality, and healthcare costs. This study aims to analyze the frequency, microbiology, risk factors, and outcomes of CLABSI in an adult intensive care unit. Methods We conducted a hospital-based, prospective surveillance study in the critical care unit of a tertiary care hospital. We included patients with a central line (CL) from admission until discharge or line removal. Data collection focused on patient demographics, comorbidities, CL insertion site, and CLABSI rates. The incidence of CLABSI was calculated per 1,000 CL-days, and statistical analysis was performed using the Chi-square test. Results Of the 169 patients enrolled, 123 episodes of bloodstream infections were recorded, 56 (45.5%) of which were CLABSIs. The organisms most frequently isolated were Klebsiella pneumoniae (n = 14; 24.6%), Enterobacter cloacae complex (n = 11; 19.3%), Klebsiella species (n = 7; 12.28%), and Acinetobacter baumannii (n = 7; 12.28%). The overall CLABSI rate was 24.70 per 1,000 CL-days. No significant association was found between CLABSI and patient age, gender, or the site of CL insertion. However, a significant relationship was observed between CLABSI and the presence of comorbid conditions (p = 0.001). The study also noted a high rate of antibiotic resistance among the isolated pathogens. Conclusions Our results emphasize the need for stringent infection control measures and suggest that comorbid conditions significantly increase the risk of CLABSI. Addressing antibiotic resistance and implementing effective prevention strategies are essential for reducing the burden of CLABSIs.

Examining pancreatic stone protein response in ICU-acquired bloodstream infections: a matched event analysis.

Pancreatic stone protein (PSP) exhibits potential as a plasma biomarker for infection diagnosis and risk stratification in critically ill patients, but its significance in nosocomial infection and intensive care unit (ICU)-acquired bloodstream infection (BSI) remains unclear. This study explores the temporal responses of PSP in ICU-acquired BSI caused by different pathogens. From a large cohort of ICU patients, we selected episodes of ICU-acquired BSI caused by Gram-negative rods (GNRs), enterococci, or Candida species. Events were matched on length of ICU stay at infection onset, Severe Organ Failure Assessment (SOFA) score, presence of immune deficiency, and use of renal replacement therapy. PSP concentrations were measured at infection onset (T0) and at 24, 48 and 72h prior to infection onset as defined by the first occurrence of a positive blood culture. Absolute and trend differences in PSP levels between pathogen groups were analysed using one-way analysis of variance. Sensitivity analyses were performed in events with a new or worsening systematic inflammatory response based on C-reactive protein, white cell count and fever. We analysed 30 BSI cases per pathogen group. Median (IQR) BSI onset was on day 9 (6-12). Overall, PSP levels were high (381 (237-539) ng/ml), with 18% of values exceeding the assay's measurement range. Across all 90 BSI cases, there was no clear trend over time (median change 34 (- 75-189) ng/ml from T-72 to T0). PSP concentrations at infection onset were 406 (229-497), 350 (223-608), and 480 (327-965) ng/ml, for GNR, enterococci, and Candida species, respectively (p = 0.32). At every time point, absolute PSP levels and trends did not differ significantly between pathogens. PSP values at T0 correlated with SOFA scores. Eighteen (20%) of 90 BSI events did not exhibit a systemic inflammatory response, primarily in Candida species. No clear change in PSP concentration before BSI onset or between-group differences were found in sensitivity analyses of 72 cases. Against a background of overall (very) high plasma PSP levels in critically ill patients, we did not find clear temporal patterns or any pathogen-specific differences in PSP response in the days preceding onset of ICU-acquired BSI.

Risk of death in Klebsiella pneumoniae bloodstream infections is associated with specific phylogenetic lineages

Klebsiella pneumoniae species complex (KpSC) bloodstream infections (BSIs) are associated with considerable morbidity and mortality, particularly in elderly and multimorbid patients. Multidrug-resistant (MDR) strains have been associated with poorer outcome. However, the clinical impact of KpSC phylogenetic lineages on BSI outcome is unclear. In an 18-month nationwide Norwegian prospective study of KpSC BSI episodes in adults, we used whole-genome sequencing to describe the molecular epidemiology of KpSC, and multivariable Cox regression analysis including clinical data to determine adjusted hazard ratios (aHR) for death associated with specific genomic lineages. We included 1078 BSI episodes and 1082 bacterial isolates from 1055 patients. The overall 30-day case-fatality rate (CFR) was 12.5%. Median patient age was 73.4, 61.7% of patients were male. Median Charlson comorbidity score was 3. Klebsiella pneumoniae sensu stricto (Kp) (79.3%, n=858/1082) and K. variicola (15.7%, n=170/1082) were the dominating phylogroups. Global MDR-associated Kp clonal groups (CGs) were prevalent (25.0%, n=270/1082) but 78.9% (n=213/270) were not MDR, and 53.7% (n=145/270) were community acquired. The major findings were increased risk for death within 30 days in monomicrobial BSIs caused by K. variicola (CFR 16.9%, n=21; aHR 1.86, CI 1.10-3.17, p=0.02), and global MDR-associated Kp CGs (CFR 17.0%, n=36; aHR 1.52, CI 0.98-2.38, p=0.06) compared to Kp CGs not associated with MDR (CFR 10.1%, n=46). Bacterial traits, beyond antimicrobial resistance, have a major impact on the clinical outcome of KpSC BSIs. The global spread of MDR-associated Kp CGs is driven by other mechanisms than antibiotic selection alone. Further insights into virulence determinants, and their association with phylogenetic lineages are needed to better understand the epidemiology of KpSC infection and clinical outcome.

Proteus species bloodstream infections: Comparative epidemiology of three species

BackgroundAlthough Proteus species are occasional causes of serious infections, their epidemiology has not been well defined. The objective was to describe the overall and species-specific occurrence and determinants of Proteus species bloodstream infection (BSI) in a large Australian population. MethodsAll Queensland residents with Proteus species BSI identified within the publicly funded healthcare system between 2000 and 2019 were included. ResultsA total of 2,143 incident episodes of Proteus species BSI were identified among 2,079 Queensland residents. The prevalence of comorbid illness differed with higher Charlson comorbidity scores observed with P. penneri and P. vulgaris, and higher prevalence of liver disease with P. penneri, higher comorbid cancer with P. vulgaris, and lower diabetes and renal disease prevalence with P. mirabilis BSIs. ConclusionThis study provides novel information on the epidemiology of Proteus species BSI.

Cardiac implantable electronic devices and bloodstream infections: management and outcomes.

Bloodstream infection (BSI) of any cause may lead to device infection in cardiac implantable electronic device (CIED) patients. Aiming for a better understanding of the diagnostic approach, treatment, and outcome, patients with an implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy and defibrillator (CRT-D) hospitalized with BSI were investigated. This is a single-centre, retrospective, cohort analysis including consecutive ICD/CRT-D patients implanted between 2012 and 2021. These patients were screened against a list of all hospitalized patients having positive blood cultures consistent with diagnosed infection in any department of a local public hospital. The total cohort consisted of 515 patients. Over a median follow-up of 59 months (interquartile range 31-87 months), there were 47 BSI episodes in 36 patients. The majority of patients with BSI (92%) was admitted to non-cardiology units, and in 25 episodes (53%), no cardiac imaging was performed. Nearly all patients (85%) were treated with short-term antibiotics, whereas chronic antibiotic suppression therapy (n = 4) and system extraction (n = 3) were less frequent. Patients with BSI had a nearly seven-fold higher rate (hazard ratio 6.7, 95% confidence interval 3.9-11.2; P < .001) of all-cause mortality. Diagnostic workup of defibrillator patients with BSI admitted to a non-cardiology unit is often insufficient to characterize lead-related endocarditis. The high mortality rate in these patients with BSI may relate to underdiagnosis and consequently late/absence of system removal. Efforts to increase an interdisciplinary approach and greater use of cardiac imaging are necessary for timely diagnosis and adequate treatment.

Early assessment of blood culture negativity as a potential support tool for antimicrobial stewardship

ObjectiveTo assess whether 48-h negative blood culture (BC) bottles are still negative at the classic 120-h incubation endpoint and whether 48 h might be the time to make antimicrobial therapy decisions. MethodsData from the first collected bottles from bloodstream infection (BSI) episodes of single patients were retrospectively analyzed. Probabilities of bottles being negative at the classic endpoint were calculated from 0 to 120 h of incubation. ResultsAmong BC-negative episodes (4018/4901 [82.0%]), most (2097/4018 (52.2%) occurred in medicine patients. At 48 h, probability was 100.0% (95% CI, 99.9–100.0) for all 4018 patients. Of these, 1244 (31.0%) patients remained on antibiotics until 120 h. Excluding 401 (32.2%) patients who received antibiotics for another (non-bloodstream) infection, 843 (67.8%) of 1244 patients could have merited early (48-h) discontinuation of antibiotics. Stopping treatment in these patients would have led to saving 5201 days of access (943 [18.1%] days), watch (3624 [69.7%] days), or reserve (634 [12.2%]) AWaRe groups’ antibiotics, which correspond to 65.6% (5201/7928) of days of administered antibiotics in all 1244 patients. ConclusionAs an early indicator of BC negativity, the 48-h endpoint could reliably support antimicrobial stewardship, but the clinical judgment remains imperative especially when BSI is highly suspected.

Bloodstream infections: trends and evolution of incidence and etiology in a 12-year period (2010–2021)

Introduction The epidemiological evolution of bloodstream infections (BSIs) in the last decade is not clearly defined. Our aim was to analyze the changes in the workload in our institution and to describe the evolution of the incidence and etiology of BSIs in a 12-year period, including the COVID-19 pandemic. Methods All blood cultures received in the laboratory of a tertiary general hospital between 2010 and 2021 were analyzed. Bloodstream infection episodes refer to each episode of bacteremia or fungemia in each patient. Incidence rates per 1000 admissions and per 100,000 population were calculated. Results No significant changes in the incidence of BSI episodes/1000 admissions were observed (mean, 31.1), while estimated population-based incidences showed declining trends (mean, 182.8/100,000 inhabitants). There was a slight increase in BSI episodes per 1000 admissions caused by Gram-negatives (mean, 16.6/1000 admissions) and E. coli was the most frequent pathogen (mean, 8.5/1000 admissions). There was no significant rise in episodes caused by ESBL- and carbapenemase-producing E. coli or K. pneumoniae, with a decline in those caused by methicillin-resistant S. aureus. A spike in BSI episodes, fungal BSIs and catheter-related infections was detected in 2020, during the COVID-19 outbreak. Conclusions No clear increase in the incidence of BSI episodes was detected in our center over this period. Gram-negatives are the most frequent etiology, with no clear rise in antimicrobial resistance phenotypes. The COVID-19 pandemic accounted for a small increase in BSI episodes in 2020, probably related to the increase of catheter-related infections.

Factors associated with foreign body infection in methicillin-resistant Staphylococcus aureus bacteremia.

We aimed to compare patient characteristics, MRSA sequence types, and biofilm production of MRSA strains that did and did not cause a foreign body infection in patients with MRSA bloodstream infections (BSI). All adult patients with MRSA BSI hospitalized in two hospitals were identified by clinical microbiology laboratory surveillance. Only patients who had at least one implanted foreign body during the episode of BSI were included. In July 2018 - March 2022, of 423 patients identified with MRSA BSI, 118 (28%) had ≥1 foreign body. Among them, 51 (43%) had one or more foreign body infections. In multivariable analysis, factors associated with foreign body infection were history of MRSA infection in the last year (OR=4.7 [1.4-15.5], p=0.012) community-associated BSI (OR=68.1 [4.2-1114.3], p=0.003); surgical site infection as source of infection (OR=11.8 [2-70.4], p=0.007); presence of more than one foreign body (OR=3.4 [1.1-10.7], p=0.033); interval between foreign body implantation and infection <18 months (OR=3.3 [1.1-10], p=0.031); and positive blood culture ≥48h (OR=16.7 [4.3-65.7], p<0.001). The most prevalent sequence type was ST8 (39%), followed by ST5 (29%), and ST105 (20%) with no significant difference between patients with or without foreign body infection. Only 39% of MRSA isolates formed a moderate/strong biofilm. No significant difference was observed between patients with foreign body infection and those without foreign body infection. In multivariable analysis, subjects infected with a MRSA isolate producing moderate/strong in vitro biofilm were more likely to have a history of MRSA infection in the last year (OR=3.41 [1.23-9.43]), interval between foreign body implantation and MRSA BSI <18 months (OR=3.1 [1.05-9.2]) and ST8 (OR=10.64 [2-57.3]). Most factors associated with foreign body infection in MRSA BSI were also characteristic of persistent infections. Biofilm-forming isolates were not associated with a higher risk of foreign-body infection but appeared to be associated with MRSA genetic lineage, especially ST8.