The Effect of Molecular Rapid Diagnostic Testing on Clinical Outcomes in Bloodstream Infections: A Systematic Review and Meta-analysis

The impact of optimizing microbial diagnosis processes on clinical and healthcare economic outcomes in hospitalized patients with bloodstream infections

PURPOSE

Bloodstream infections (BSIs) are associated with significant morbidity, mortality and costs, while prolonged blood culture (BC) diagnosis may delay the initiation of targeted therapy. This study evaluates the impact of an optimized microbiology laboratory process on turnaround times, antibiotic use, clinical outcomes and economics for hospitalized BSI patients.

METHODS

A pre-post study was conducted in a Chinese hospital in which BSI derived BC results before (Oct. 2020- Sep. 2021) and after (Oct. 2021- Sep. 2022) newly implemented microbiology diagnostics and workflow changes were analyzed. Turnaround times, antibiotic initiation, length of stay and in-hospital costs were compared.

RESULTS

From 213 included patients, 134 were pre-optimization (pre-op) and 79 were post-optimization (post-op) cases. The median time from blood sample collection (BSC) to pathogen identification (ID) decreased from 70.12 to 47.43 h post-op (P < 0.001). The median time from BSC to the first ID report related initiation of pathogen-directed antibiotic use decreased from 88.48 to 47.85 h post-op (P < 0.001). The average hospital stay decreased from 19.54 to 16.79 days and 30-day readmissions declined from 18.7 to 13.9%, while the mean total antimicrobial drug usage costs decreased by 3,889 CNY per patient (P = 0.022) after optimization.

CONCLUSIONS

Implementing new diagnostics technologies and optimizing laboratory workflows significantly reduced antimicrobial drug usage costs, shortened the time to ID results and improved the timeliness of appropriate antibiotic choices to treat BSIs. Investments in faster testing and process improvements were clearly beneficial for patient outcomes and healthcare economics.

Reduced mortality with antimicrobial stewardship guided by BioFire FilmArray Blood Culture Identification 2 panel in critically ill patients with bloodstream infection: a retrospective propensity score-matched study

OBJECTIVES

To investigate whether using the BioFire® FilmArray® Blood Culture Identification 2 panel (BCID2) leads to timely antimicrobial therapy and improves patient outcomes in critically ill patients with bloodstream infections (BSIs).

METHODS

This retrospective observational study included patients with BSIs admitted to the intensive care unit from July 1, 2021, to August 31, 2023. Patients were divided into groups receiving appropriate or inappropriate antimicrobial therapy. Those receiving inappropriate therapy underwent adjustments using standard-of-care (SOC) testing or BCID2. Propensity score matching (PSM) was performed on the original cohort (Model 1) and a time-window bias-adjusted cohort (Model 2). Clinical impact of BCID2-guided antimicrobial adjustment was analyzed in both models.

RESULTS

A total of 181 patients received inappropriate antimicrobial therapy, with 33 undergoing BCID2 testing and 148 undergoing SOC testing. Following PSM and time-window bias adjustment, 66 patients were analyzed in Model 1 and 46 patients in Model 2. BCID2 significantly reduced the median time to appropriate antimicrobial therapy (40.8 vs. 74.0 h in Model 1; 42.8 vs. 68.9 h in Model 2) and the day-28 mortality rate (27.8% vs. 77.1%, p < 0.001 in Model 1; 23.5% vs. 58.6%, p = 0.021 in Model 2). In multivariate regression analysis, BCID2-guided antimicrobial adjustment was an independent prognostic factor for day-28 mortality (adjusted odds ratio [aOR] 0.07 in Model 1 and aOR 0.12 in Model 2).

CONCLUSION

BCID2-guided antimicrobial stewardship was associated with a shorter time to appropriate antimicrobial therapy and reduced day-28 mortality in critically ill patients with BSIs receiving inappropriate antimicrobial therapy.

Rapid Diagnostic Tests and Antimicrobial Stewardship Programs for the Management of Bloodstream Infection: What Is Their Relative Contribution to Improving Clinical Outcomes? A Systematic Review and Network Meta-analysis

BACKGROUND

Evidence about the clinical impact of rapid diagnostic tests (RDTs) for the diagnosis of bloodstream infections is limited, and whether RDT are superior to conventional blood cultures (BCs) embedded within antimicrobial stewardship programs (ASPs) is unknown.

METHODS

We performed network meta-analyses using results from studies of patients with bloodstream infection with the aim of comparing the clinical impact of RDT (applied on positive BC broth or whole blood) to conventional BC, both assessed with and without ASP with respect to mortality, length of stay (LOS), and time to optimal therapy.

RESULTS

Eighty-eight papers were selected, including 25 682 patient encounters. There was an appreciable amount of statistical heterogeneity within each meta-analysis. The network meta-analyses showed a significant reduction in mortality associated with the use of RDT + ASP versus BC alone (odds ratio [OR], 0.72; 95% confidence interval [CI], .59-.87) and with the use of RDT + ASP versus BC + ASP (OR, 0.78; 95% CI, .63-.96). No benefit in survival was found associated with the use of RDT alone nor with BC + ASP compared to BC alone. A reduction in LOS was associated with RDT + ASP versus BC alone (OR, 0.91; 95% CI, .84-.98) whereas no difference in LOS was shown between any other groups. A reduced time to optimal therapy was shown when RDT + ASP was compared to BC alone (-29 hours; 95% CI, -35 to -23), BC + ASP (-18 hours; 95% CI, -27 to -10), and to RDT alone (-12 hours; 95% CI, -20 to -3).

CONCLUSIONS

The use of RDT + ASP may lead to a survival benefit even when introduced in settings already adopting effective ASP in association with conventional BC.

Clinical evaluation of droplet digital pcr for suspected ascites infection in patients with liver cirrhosis

BACKGROUND

Droplet digital PCR (ddPCR) is increasingly used in diagnosing clinical pathogens, but its effectiveness in cirrhosis patients with suspected ascites infection remains uncertain.

METHODS

The diagnostic performance of ddPCR was assessed in 305 ascites samples, utilizing culture and clinical composite standards. The quantitative value and potential clinical impact of ddPCR were further analyzed in patients with spontaneous bacterial peritonitis.

RESULTS

With culture standards, ddPCR demonstrated a sensitivity of 86.5% and specificity of 83.2% for bacterial or fungal detection. After adjustment of clinical composite criteria, specificity increased to 96.4%. Better diagnostic performance for all types of targeted pathogens, particularly fungi, was observed with ddPCR compared to culture, and more polymicrobial infections were detected (30.4% versus 5.7%, p < 0.001). Pathogen loads detected by ddPCR correlated with white blood cell count in ascites and blood, as well as polymorphonuclear cell (PMN) count in ascites, reflecting infection status rapidly. A positive clinical impact of 55.8% (43/77) was observed for ddPCR, which was more significant among patients with PMN count ≤ 250/mm3 in terms of medication adjustment and new diagnosis. ddPCR results for fungal detection were confirmed by clinical symptoms and other microbiological tests, which could guide antifungal therapy and reduce the risk of short-term mortality.

CONCLUSIONS

ddPCR, with appropriate panel design, has advantages in pathogen detection and clinical management of ascites infection, especially for patients with fungal and polymicrobial infections. Patients with atypical spontaneous bacterial peritonitis benefited more from ddPCR.

Multiplex microarray PCR Unyvero BCU system to accelerate relevant antimicrobial treatment in polymicrobial bloodstream infection

PURPOSE

To evaluate the performance of a rapid multiplex microarray-based method (Unyvero BCU system, BCU) to identify microorganisms and detect antimicrobial resistance directly from positive blood culture (BC) bottles with polymicrobial growth, and to assess relevance of information provided for timely guidance of polymicrobial bloodstream infection treatment.

METHODS

Accuracy, time-to-actionable results and potential impact of BCU on antimicrobial treatment were compared with those of standard of care during a prospective study for the sample analysis (November 2017-November 2018) and a retrospective study for the clinical data analysis and the time-to-result analysis. The study was complemented with an experimental study, based on spiked blood cultures to assess the ability of the method to detect antimicrobial resistance genes.

RESULTS

Sixty-five clinical polymicrobial BC samples (163 total microorganisms) and 30 simulated polymicrobial BC samples (60 strains) were included. BCU reported 84.6% samples as polymicrobial, correctly identified all the bacteria of the mix for 72.3% samples (47/65) and detected bacteria that were missed by the conventional culture for 13.8% samples. All identifications and antimicrobial resistances were accurately detected for 61.5% (40/65) samples. Limitations concerned the detection of anaerobes, enterococci and enterobacterial susceptibility to third generation cephalosporins. BCU results would have guided antimicrobial treatment for 50.8% of the cases (33/65) in a timely and relevant manner, had no impact for 27.7% (18/65) and been misleading for 18.5% (12/65).

CONCLUSIONS

Despite some limitations, the Unyvero BCU system is a rapid and reliable method for polymicrobial BC sample analysis.

Early Diagnosis of Sepsis: The Role of Biomarkers and Rapid Microbiological Tests

Sepsis is a medical emergency resulting from a dysregulated response to an infection, causing preventable deaths and a high burden of morbidity. Protocolized and accurate interventions in sepsis are time-critical. Therefore, earlier recognition of cases allows for preventive interventions, early treatment, and improved outcomes. Clinical diagnosis of sepsis by clinical scores cannot be considered an early diagnosis, given that underlying molecular pathophysiological mechanisms have been activated in the preceding hour or days. There is a lack of a widely available tool enhancing preclinical diagnosis of sepsis. Sophisticated technologies for sepsis prediction have several limitations, including high costs. Novel technologies for fast molecular and microbiological diagnosis are focusing on bedside point-of-care combined testing to reach most settings where sepsis represents a challenge.

eHealth and mHealth in Antimicrobial Stewardship to Reduce Mortality in Empirical Antimicrobial Therapy and a Systematic Review with a Meta-Analysis of Adequate Therapy

The urgent requirement for swift diagnostic methods in pathogen identification and antimicrobial susceptibility testing is emphasized by rising bacterial resistance and limited treatment options, which are particularly critical in sepsis management. The shift from traditional phenotype-based methods to rapid molecular and mass spectrometry techniques has significantly reduced result turnaround times, enhancing patient outcomes. In this systematic review with meta-analysis, the aspects of correct empirical antimicrobial therapy are evaluated to determine their impact on mortality. We performed a systematic review and meta-analysis on EMBASE, the Cochrane Library, Web of Science, and MEDLINE. Studies evaluating mortality associated with empirical adequate and inadequate therapy in different sites of infection were included. Outcomes included clinical cures in microbiologically evaluable patients. Among the sites of infection, the most studied were bloodstream infections (n = 9), followed by respiratory tract infections (n = 5), intra-abdominal infections (n = 5), and urinary tract infections (evaluated by 3 studies). Inadequate therapy was associated with an increase in mortality between 11 and 68%. Technologies to speed up pathogen identification are extremely necessary to reduce mortality.

Impact of a Bundle of Interventions on Quality-of-Care Indicators for Staphylococcus aureus Bacteraemia: A Single-Centre, Quasi-Experimental, Before-After Study

Staphylococcus aureus bacteraemia (SAB) is a life-threatening bloodstream infection. Improved adherence to quality-of-care indicators (QCIs) can significantly enhance patient outcomes. This quasi-experimental study evaluated the impact of a bundle of interventions on QCI adherence in adult patients with SAB. Additionally, a molecular rapid diagnostic test (mRDT) for S. aureus and methicillin resistance was introduced during weekdays. We compared pre-intervention (January-December 2022) and post-intervention (May 2023-April 2024) data on QCI adherence and time to appropriate treatment. A total of 56 and 40 SAB episodes were included in the pre- and post-intervention periods, respectively. Full QCI adherence significantly increased from 28.6% to 67.5% in the post-intervention period (p < 0.001). The mRDT diagnosed SAB in eight cases (26.6%), but the time to achieve appropriate target therapy did not improve in the post-intervention period (54 h (IQR 30-74) vs. 72 h (IQR 51-83), p = 0.131). The thirty-day mortality rate was comparable between the two periods (17.9% vs. 12.5%, p = 0.476). This study demonstrates that a bundle of interventions can substantially improve adherence to SAB management QCIs.

Treatment of multidrug-resistant Gram-negative bloodstream infections in critically ill patients: an update

PURPOSE OF REVIEW

This review describes the latest information in the management of bloodstream infections caused by multidrug-resistant Gram-negative bacilli (MDRGNB) in critically ill patients.

RECENT FINDINGS

The prevalence of bloodstream infections due to MDRGNB is high, and they pose a significant risk in critically ill patients. Recently, novel antimicrobial agents, including new β-lactam/β-lactamase inhibitor combinations and cefiderocol, have been introduced for treating these infections. Concurrently, updated guidelines have been issued to aid in treatment decisions. Prompt diagnosis and identification of resistance patterns are crucial for initiating effective antibiotic therapy. Current studies, especially with observational design, and with limited sample sizes and patients with bacteremia, suggest that the use of these new antibiotics is associated with improved outcomes in critically ill patients with MDRGNB bloodstream infections.

SUMMARY

For critically ill patients with bloodstream infections caused by MDRGNB, the use of newly developed antibiotics is recommended based on limited observational evidence. Further randomized clinical trials are necessary to determine the most effective antimicrobial therapies among the available options.

Opportunities to Enhance Diagnostic Testing and Antimicrobial Stewardship: A Qualitative Multinational Survey of Healthcare Professionals

INTRODUCTION

Antimicrobial resistance (AMR) is a global public health challenge. Global efforts to decrease AMR through antimicrobial stewardship (AMS) initiatives include education and optimising the use of diagnostic technologies and antibiotics. Despite this, economic and societal challenges hinder AMS efforts. The objective of this study was to obtain insights from healthcare professionals (HCPs) on current challenges and identify opportunities for optimising diagnostic test utilisation and AMS efforts.

METHODS

Three hundred HCPs from six countries (representing varied gross national incomes per capita, healthcare system structure, and AMR rates) were surveyed between November 2022 through January 2023. A targeted literature review and expert interviews were conducted to inform survey development. Descriptive statistics were used to summarise survey responses.

RESULTS

These findings suggest that the greatest challenges to diagnostic test utilisation were economic in nature; many HCPs reported that AMS initiatives were lacking investment (32.3%) and resourcing (40.3%). High resistance rates were considered the greatest barriers to appropriate antimicrobial use (52.0%). Most HCPs found local and national guidelines to be very useful (≥ 51.0%), but areas for improvement were noted. The importance of AMS initiatives was confirmed; diagnostic practices were acknowledged to have a positive impact on decreasing AMR (70.3%) and improving patient outcomes (81.0%).

CONCLUSION

AMS initiatives, including diagnostic technology utilisation, are pivotal to decreasing AMR rates. Interpretation of these survey results suggests that while HCPs consider diagnostic practices to be important in AMS efforts, several barriers to successful implementation still exist including patient/institutional costs, turnaround time of test results, resourcing, AMR burden, and education. While some barriers differ by country, these survey results highlight areas of opportunities in all countries for improved use of diagnostic technologies and broader AMS efforts, as perceived by HCPs. Greater investment, resourcing, education, and updated guidelines offer opportunities to further strengthen global AMS efforts.

Performance of ePlex® blood culture identification panels in clinical isolates and characterization of antimicrobial stewardship opportunities

We assessed the performance of GenMark's ePlex® Blood Culture Identification (BCID) Panels for overall agreement of organism identification and resistance mechanism detection with standard microbiologic methods. This study included patients with a positive blood culture from May 2020 to January 2021. The primary outcomes were to assess concordance of ePlex® organism identification with standard identification methods and concordance of ePlex® genotypic resistance mechanism detection with standard phenotypic susceptibility testing. Secondary outcomes included panel specific performance and characterization of antimicrobial stewardship opportunities. The overall identification concordance rate in 1276 positive blood cultures was 98.1%. The overall concordance for the presence of resistance markers was 98.2% and concordance for the absence of resistance markers was 100%. A majority of ePlex® results (69.5%) represented opportunities for potential antimicrobial stewardship intervention. High concordance rates between the ePlex® BCID panels and standard identification and susceptibility methods enable utilization of results to guide rapid antimicrobial optimization.

Proteomic assay for rapid characterisation of Staphylococcus aureus antimicrobial resistance mechanisms directly from blood cultures

PURPOSE

Staphylococcus aureus is one of the most common pathogens causing bloodstream infection. A rapid characterisation of resistance to methicillin and, occasionally, to aminoglycosides for particular indications, is therefore crucial to quickly adapt the treatment and improve the clinical outcomes of septic patients. Among analytical technologies, targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) has emerged as a promising tool to detect resistance mechanisms in clinical samples.

METHODS

A rapid proteomic method was developed to detect and quantify the most clinically relevant antimicrobial resistance effectors in S. aureus in the context of sepsis: PBP2a, PBP2c, APH(3')-III, ANT(4')-I, and AAC(6')-APH(2''), directly from positive blood cultures and in less than 70 min including a 30-min cefoxitin-induction step. The method was tested on spiked blood culture bottles inoculated with 124 S.aureus, accounting for the known genomic diversity of SCCmec types and the genetic background of the strains.

RESULTS

This method provided 99% agreement for PBP2a (n = 98/99 strains) detection. Agreement was 100% for PBP2c (n = 5/5), APH(3')-III (n = 16/16), and ANT(4')-I (n = 20/20), and 94% for AAC(6')-APH(2'') (n = 16/17). Across the entire strain collection, 100% negative agreement was reported for each of the 5 resistance proteins. Additionally, relative quantification of ANT(4')-I expression allowed to discriminate kanamycin-susceptible and -resistant strains, in all strains harbouring the ant(4')-Ia gene.

CONCLUSION

The LC-MS/MS method presented herein demonstrates its ability to provide a reliable determination of S. aureus resistance mechanisms, directly from positive blood cultures and in a short turnaround time, as required in clinical laboratories.

Time Is of the Essence: Achieving Prompt and Effective Antimicrobial Therapy of Bloodstream Infection With Advanced Hospital Information Systems

The early administration of appropriate antibiotic therapy is crucial for the survival of patients with bacteremia. Current research focuses on improving analytical times through technology, whereas there have been very few efforts to improve postanalytical times even though they represent 40% of the time between blood taking and appropriate treatment administration. One of the clues is the efficiency and appropriateness of the result communication system. Here, we review all delays in the entire process with the aim of improving time to appropriate treatment administration. We discuss causes for long times to adjust treatment once microbiological results are released. We argue that the pervasive health information system in this organization serves as both a bottleneck and a rigid framework. Finally, we explore how next-generation hospital information systems should be designed to effectively assist the doctors in treating patients with bacteremia.

Management of intra-abdominal infections: recommendations by the Italian council for the optimization of antimicrobial use

Intra-abdominal infections (IAIs) are common surgical emergencies and are an important cause of morbidity and mortality in hospital settings, particularly if poorly managed. The cornerstones of effective IAIs management include early diagnosis, adequate source control, appropriate antimicrobial therapy, and early physiologic stabilization using intravenous fluids and vasopressor agents in critically ill patients. Adequate empiric antimicrobial therapy in patients with IAIs is of paramount importance because inappropriate antimicrobial therapy is associated with poor outcomes. Optimizing antimicrobial prescriptions improves treatment effectiveness, increases patients' safety, and minimizes the risk of opportunistic infections (such as Clostridioides difficile) and antimicrobial resistance selection. The growing emergence of multi-drug resistant organisms has caused an impending crisis with alarming implications, especially regarding Gram-negative bacteria. The Multidisciplinary and Intersociety Italian Council for the Optimization of Antimicrobial Use promoted a consensus conference on the antimicrobial management of IAIs, including emergency medicine specialists, radiologists, surgeons, intensivists, infectious disease specialists, clinical pharmacologists, hospital pharmacists, microbiologists and public health specialists. Relevant clinical questions were constructed by the Organizational Committee in order to investigate the topic. The expert panel produced recommendation statements based on the best scientific evidence from PubMed and EMBASE Library and experts' opinions. The statements were planned and graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) hierarchy of evidence. On November 10, 2023, the experts met in Mestre (Italy) to debate the statements. After the approval of the statements, the expert panel met via email and virtual meetings to prepare and revise the definitive document. This document represents the executive summary of the consensus conference and comprises three sections. The first section focuses on the general principles of diagnosis and treatment of IAIs. The second section provides twenty-three evidence-based recommendations for the antimicrobial therapy of IAIs. The third section presents eight clinical diagnostic-therapeutic pathways for the most common IAIs. The document has been endorsed by the Italian Society of Surgery.

Clinical evaluation of droplet digital PCR in the early identification of suspected sepsis patients in the emergency department: a prospective observational study

Background

Rapid and accurate diagnosis of the causative agents is essential for clinical management of bloodstream infections (BSIs) that might induce sepsis/septic shock. A considerable number of suspected sepsis patients initially enter the health-care system through an emergency department (ED), hence it is vital to establish an early strategy to recognize sepsis and initiate prompt care in ED. This study aimed to evaluate the diagnostic performance and clinical value of droplet digital PCR (ddPCR) assay in suspected sepsis patients in the ED.

Methods

This was a prospective single-centered observational study including patients admitted to the ED from 25 October 2022 to 3 June 2023 with suspected BSIs screened by Modified Shapiro Score (MSS) score. The comparison between ddPCR and blood culture (BC) was performed to evaluate the diagnostic performance of ddPCR for BSIs. Meanwhile, correlative analysis between ddPCR and the inflammatory and prognostic-related biomarkers were conducted to explore the relevance. Further, the health economic evaluation of the ddPCR was analyzed.

Results

258 samples from 228 patients, with BC and ddPCR performed simultaneously, were included in this study. We found that ddPCR results were positive in 48.13% (103 of 214) of episodes, with identification of 132 pathogens. In contrast, BC only detected 18 positives, 88.89% of which were identified by ddPCR. When considering culture-proven BSIs, ddPCR shows an overall sensitivity of 88.89% and specificity of 55.61%, the optimal diagnostic power for quantifying BSI through ddPCR is achieved with a copy cutoff of 155.5. We further found that ddPCR exhibited a high accuracy especially in liver abscess patients. Among all the identified virus by ddPCR, EBV has a substantially higher positive rate with a link to immunosuppression. Moreover, the copies of pathogens in ddPCR were positively correlated with various markers of inflammation, coagulation, immunity as well as prognosis. With high sensitivity and specificity, ddPCR facilitates precision antimicrobial stewardship and reduces health care costs.

Conclusions

The multiplexed ddPCR delivers precise and quantitative load data on the causal pathogen, offers the ability to monitor the patient's condition and may serve as early warning of sepsis in time-urgent clinical situations as ED.

Importance

Early detection and effective administration of antibiotics are essential to improve clinical outcomes for those with life-threatening infection in the emergency department. ddPCR, an emerging tool for rapid and sensitive pathogen identification used as a precise bedside test, has developed to address the current challenges of BSI diagnosis and precise treatment. It characterizes sensitivity, specificity, reproducibility, and absolute quantifications without a standard curve. ddPCR can detect causative pathogens and related resistance genes in patients with suspected BSIs within a span of three hours. In addition, it can identify polymicrobial BSIs and dynamically monitor changes in pathogenic microorganisms in the blood and can be used to evaluate antibiotic efficacy and survival prognosis. Moreover, the copies of pathogens in ddPCR were positively correlated with various markers of inflammation, coagulation, immunity. With high sensitivity and specificity, ddPCR facilitates precision antimicrobial stewardship and reduces health care costs.

Clinical impact and cost-consequence analysis of ePlex® blood culture identification panels for the rapid diagnosis of bloodstream infections: a single-center randomized controlled trial

To assess clinical impact and perform cost-consequence analysis of the broadest multiplex PCR panels available for the rapid diagnosis of bloodstream infections (BSI). Single-center, randomized controlled trial conducted from June 2019 to February 2021 at a French University hospital with an institutional antimicrobial stewardship program. Primary endpoint was the percentage of patients with optimized antimicrobial treatment 12 h after transmission of positivity and Gram stain results from the first positive BC. This percentage was significantly higher in the multiplex PCR (mPCR) group (90/105 = 85.7% %, CI95% [77.5 ; 91.8] vs. 68/107 = 63.6%, CI95% [53.7 ; 72.6]; p < 10- 3) at interim analysis, resulting in the early termination of the study after the inclusion of 309 patients. For patients not optimized at baseline, the median time to obtain an optimized therapy was much shorter in the mPCR group than in the control group (6.9 h, IQR [2.9; 17.8] vs. 26.4 h, IQR [3.4; 47.5]; p = 0.001). Early optimization of antibiotic therapy resulted in a non-statistically significant decrease in mortality from 12.4 to 8.8% (p = 0.306), with a trend towards a shorter median length of stay (18 vs. 20 days; p = 0.064) and a non-significant reduction in the average cost per patient of €3,065 (p = 0.15). mPCR identified all the bacteria present in 88% of the samples. Despite its higher laboratory cost, the use of multiplex PCR for BSI diagnosis leads to early-optimised therapy, seems cost-effective and could reduce mortality and length of stay. Their impact could probably be improved if implemented 24/7.

The Molecular Mouse System: A New Useful Tool for Guiding Antimicrobial Therapy in Critically Ill Septic Patients

Bloodstream infections (BSI) caused by multidrug-resistant (MDR) bacteria, pose a major threat for patients, especially for those who are immunosuppressed. Rapid pathogen detection and characterization from positive blood cultures are crucial in the management of patients with BSI to enable an adequate and timely antimicrobial therapy. This study aimed to investigate the potential role of the Molecular Mouse system, a new CE IVD molecular test designed to rapidly detect the causative agents of bacteremia and their resistance determinants, in the management of the therapy in critically ill patients. Agreement between the results of the Molecular Mouse and the conventional routine method was also considered. Overall, 100 positive blood cultures were collected from septic critically ill patients from May 2023 to January 2024 and analyzed with Molecular Mouse and routine protocols. The new instrument consistently agreed with the routine protocols in the case of monomicrobial blood cultures, while some discrepancies were obtained in the polymicrobial samples. Antimicrobial resistance genes were detected in 35 samples, with vanA and CTX-M-1/9 groups being the most frequently detected targets. Therapy was adjusted in 42 critically ill patients confirming the importance of new rapid molecular tests in the management of positive blood cultures, to adjust empirical therapy and use new antibiotics accurately.

Rapid Direct Identification of Microbial Pathogens and Antimicrobial Resistance Genes in Positive Blood Cultures Using a Fully Automated Multiplex PCR Assay

This study assessed the performance of the BioFire Blood Culture Identification 2 (BCID2) panel in identifying microorganisms and antimicrobial resistance (AMR) profiles in positive blood cultures (BCs) and its influence on turnaround time (TAT) compared with conventional culture methods. We obtained 117 positive BCs, of these, 102 (87.2%) were correctly identified using BCID2. The discordance was due to off-panel pathogens detected by culture (n = 13), and additional pathogens identified by BCID2 (n = 2). On-panel pathogen concordance between the conventional culture and BCID2 methods was 98.1% (102/104). The conventional method detected 19 carbapenemase-producing organisms, 14 extended-spectrum beta-lactamase-producing Enterobacterales, 18 methicillin-resistant Staphylococcus spp., and four vancomycin-resistant Enterococcus faecium. BCID2 correctly predicted 53 (96.4%) of 55 phenotypic resistance patterns by detecting AMR genes. The TAT for BCID2 was significantly lower than that for the conventional method. BCID2 rapidly identifies pathogens and AMR genes in positive BCs.

Prognostic value of poly-microorganisms detected by droplet digital PCR and pathogen load kinetics in sepsis patients: a multi-center prospective cohort study

This study aimed to investigate the prognostic value of a novel droplet digital polymerase chain reaction (DDPCR) assay in sepsis patients. In this prospective cohort study, univariable and multivariable Cox regressions were used to assess risk factors for 28-day mortality. We also monitored pathogen load together with clinical indicators in a subgroup of the cohort. A total of 107 sepsis patients with positive baseline DDPCR results were included. Detection of poly-microorganisms [adjusted hazard ratio (HR) = 3.19; 95% confidence interval (CI) = 1.34-7.62; P = 0.009], high Charlson Comorbidity Index (CCI) score (adjusted HR = 1.14; 95% CI = 1.01-1.29; P = 0.041), and Sequential Organ Failure Assessment (SOFA) score (adjusted HR = 1.18; 95% CI = 1.05-1.32; P = 0.005) at baseline were independent risk factors for 28-day mortality while initial pathogen load was not associated (adjusted HR = 1.17; 95% CI = 0.82-1.66; P = 0.385). Among 63 patients with serial DDPCR results, an increase in pathogen load at days 6-8 compared to baseline was a risk factor for 28-day mortality (P = 0.008). Also, pathogen load kinetics were significantly different between day-28 survivors and nonsurvivors (P = 0.022), with a decline overtime only in survivors and an increase from days 3 and 4 to days 6-8 in nonsurvivors. Using DDPCR technique, we found that poly-microorganisms detected and increased pathogen load a week after sepsis diagnosis were associated with poor prognosis.IMPORTANCEThis prospective study was initiated to explore the prognostic implications of a novel multiplex PCR assay in sepsis. Notably, our study was the largest cohort of sepsis with droplet digital polymerase chain reaction pathogen monitoring to date, allowing for a comprehensive evaluation of the prognostic significance of both pathogen species and load. We found that detection of poly-microorganisms was an independent risk factors for 28-day mortality. Also, pathogen load increase 1 week after sepsis diagnosis was a risk factor for 28-day mortality, and differential pathogen load kinetics were identified between day-28 survivors and nonsurvivors. Overall, this study demonstrated that pathogen species and load were highly correlated with sepsis prognosis. Patients exhibiting conditions mentioned above face a more adverse prognosis, suggesting the potential need for an escalation of antimicrobial therapy.Registered at ClinicalTrials.gov (NCT05190861).

The importance of pharmacist engagement in diagnostic stewardship

Diagnostic stewardship is increasingly recognized as a powerful tool to improve patient safety. Given the close relationship between diagnostic testing and antimicrobial misuse, antimicrobial stewardship (AMS) pharmacists should be key members of the diagnostic team. Pharmacists practicing in AMS already frequently engage with clinicians to improve the diagnostic process and have many skills needed for the implementation of diagnostic stewardship initiatives. As diagnostic stewardship becomes more broadly used, all infectious disease clinicians, including pharmacists, must collaborate to optimize patient care.

Breaking Boundaries in Pneumonia Diagnostics: Transitioning from Tradition to Molecular Frontiers with Multiplex PCR

The advent of rapid molecular microbiology testing has revolutionized infectious disease diagnostics and is now impacting pneumonia diagnosis and management. Molecular platforms offer highly multiplexed assays for diverse viral and bacterial detection, alongside antimicrobial resistance markers, providing the potential to significantly shape patient care. Despite the superiority in sensitivity and speed, debates continue regarding the clinical role of multiplex molecular testing, notably in comparison to standard methods and distinguishing colonization from infection. Recent guidelines endorse molecular pneumonia panels for enhanced sensitivity and rapidity, but implementation requires addressing methodological differences and ensuring clinical relevance. Diagnostic stewardship should be leveraged to optimize pneumonia testing, emphasizing pre- and post-analytical strategies. Collaboration between clinical microbiologists and bedside providers is essential in developing implementation strategies to maximize the clinical utility of multiplex molecular diagnostics in pneumonia. This narrative review explores these multifaceted issues, examining the current evidence on the clinical performance of multiplex molecular assays in pneumonia, and reflects on lessons learned from previous microbiological advances. Additionally, given the complexity of pneumonia and the sensitivity of molecular diagnostics, diagnostic stewardship is discussed within the context of current literature, including implementation strategies that consider pre-analytical and post-analytical modifications to optimize the clinical utility of advanced technologies like multiplex PCR.

Clinical impacts of the rapid diagnostic method on positive blood cultures

OBJECTIVE

This study aimed to evaluate the impact of short-term incubation (STI) protocol on clinical outcomes of bloodstream infection (BSI) patients.

METHODS

A total of 1363 positive blood culture records from January 2019 to December 2021 were included. The main clinical outcomes included pathogen identification turnaround time (TAT), antimicrobial susceptibility testing (AST) TAT, and length of total hospital stay.

RESULTS

The TAT of pathogen identification and AST significantly decreased after implementing the STI protocol (2.2 vs 1.4 days and 3.4 vs 2.5 days, respectively, with P < .001 for both). Moreover, for patients with Gram-negative bacteria (GNB)-infected BSIs, the length of total hospital stay decreased from 31.9 days to 27.1 days, indicating that these patients could be discharged 5 days earlier after implementing the STI protocol (P < .01).

CONCLUSION

The protocol led to a significant reduction in TAT and improved clinical outcomes, particularly for GNB organisms. The findings suggest that the STI protocol can improve patient outcomes and hospital resource utilization in the management of BSIs.

The impact of the BIOFIRE® Blood Culture Identification 2 Panel on antimicrobial treatment of children with suspected systemic inflammatory response syndrome and sepsis

This study aimed to assess the therapeutic effects of implementing the BioFire® Blood Culture Identification 2 (BCID2) Panel (bioMérieux, Marcy l'Etoile, France) in the clinical practice of children with sepsis. This retrospective cross-sectional study included children from 15 days of age to 18 years old with sepsis and of whom the BCID2 Panel was studied from the positive blood culture. If the antimicrobial treatment was changed according to the results of BCID2 Panel, it was recorded and re-grouped as targeted antimicrobial therapy, de-escalation of the antimicrobial treatment and shifting to another antimicrobial drug if any antimicrobial resistance was detected. Seven-days and thirty-days mortality rate was recorded. Thirty-two patients with 36 septic episodes with positive BCID2 Panel results were included. The median age was 10 months 15 days (ranging from 15 days to 16.5 years). The mean difference between having positive results by the BCID2 Panel and conventional culture methods was 82.2 ± 45.4 h (ranging from 12.3 to 207 h). Effect of the BCID2 Panel on the antimicrobial treatment was detected in 69.4% of the episodes (n = 25). Glycopeptides were ceased at 6 patients, piperacillin/tazobactam was ceased at 6 patients, and cefotaxime was ceased at one patient and de-escalation was achieved in 13 episodes which formed the 36.1% of the initial antimicrobial treatment.   Conclusion: The BCID2 Panel had an important impact on the patients care and optimization according to the principles of antimicrobial stewardship. The BCID2 Panel may be one of the key items for rapid and accurate diagnosis in children with sepsis. Blood culture is still the mainstay for especially detection of antimicrobial drug resistance, while BCID2 tests had several advantages such as speed and diagnostic accuracy as good as blood culture. What is Known: • The BioFire® Blood Culture Identification 2 (BCID2) Panel (bioMérieux, Marcy l'Etoile, France) is a well-validated assay that allows for the simultaneous identification of 43 nucleic acid targets associated with bloodstream infections within about 1 h. What is New: • BCID2 Panel had a direct impact on the patient's treatment decision at the 69.4% of the sepsis episodes. • The clinicians received the microbiological results 82.2 h earlier with BCID2 panel compared to blood culture methods with antimicrobial resistance and de-escalation of the antimicrobial drugs was achieved at 13 episodes which formed the 36.1% of the initial treatment.

Rapid determination of antimicrobial susceptibility of Gram-negative bacteria from clinical blood cultures using a scattered light-integrated collection device

Background. A bloodstream infection (BSI) presents a complex and serious health problem, a problem that is being exacerbated by increasing antimicrobial resistance (AMR).Gap Statement. The current turnaround times (TATs) for most antimicrobial susceptibility testing (AST) methods offer results retrospective of treatment decisions, and this limits the impact AST can have on antibiotic prescribing and patient care. Progress must be made towards rapid BSI diagnosis and AST to improve antimicrobial stewardship and reduce preventable deaths from BSIs. To support the successful implementation of rapid AST (rAST) in hospital settings, a rAST method that is affordable, is sustainable and offers comprehensive AMR detection is needed.Aim. To evaluate a scattered light-integrated collection (SLIC) device against standard of care (SOC) to determine whether SLIC could accelerate the current TATs with actionable, accurate rAST results for Gram-negative BSIs.Methods. Positive blood cultures from a tertiary referral hospital were studied prospectively. Flagged positive Gram-negative blood cultures were confirmed by Gram staining and analysed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, Vitek 2, disc diffusion (ceftriaxone susceptibility only) and an SLIC device. Susceptibility to a panel of five antibiotics, as defined by European Committee on Antimicrobial Susceptibility Testing breakpoints, was examined using SLIC.Results. A total of 505 bacterial-antimicrobial combinations were analysed. A categorical agreement of 95.5 % (482/505) was achieved between SLIC and SOC. The 23 discrepancies that occurred were further investigated by the broth microdilution method, with 10 AST results in agreement with SLIC and 13 in agreement with SOC. The mean time for AST was 10.53±0.46 h and 1.94±0.02 h for Vitek 2 and SLIC, respectively. SLIC saved 23.96±1.47 h from positive blood culture to AST result.Conclusion. SLIC has the capacity to provide accurate AST 1 day earlier from flagged positive blood cultures than SOC. This significant time saving could accelerate time to optimal antimicrobial therapy, improving antimicrobial stewardship and management of BSIs.

A decade of clinical microbiology: top 10 advances in 10 years: what every infection preventionist and antimicrobial steward should know

The past 10 years have brought paradigm-shifting changes to clinical microbiology. This paper explores the top 10 transformative innovations across the diagnostic spectrum, including not only state of the art technologies but also preanalytic and post-analytic advances. Clinical decision support tools have reshaped testing practices, curbing unnecessary tests. Innovations like broad-range polymerase chain reaction and metagenomic sequencing, whole genome sequencing, multiplex molecular panels, rapid phenotypic susceptibility testing, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry have all expanded our diagnostic armamentarium. Rapid home-based testing has made diagnostic testing more accessible than ever. Enhancements to clinician-laboratory interfaces allow for automated stewardship interventions and education. Laboratory restructuring and consolidation efforts are reshaping the field of microbiology, presenting both opportunities and challenges for the future of clinical microbiology laboratories. Here, we review key innovations of the last decade.

Comparison of three rapid diagnostic tests for bloodstream infections using Benefit-risk Evaluation Framework (BED-FRAME)

Rapid diagnostic tests (RDTs) for bloodstream infections have the potential to reduce time to appropriate antimicrobial therapy and improve patient outcomes. Previously, an in-house, lipid-based, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) method, Fast Lipid Analysis Technique (FLAT MS), has shown promise as a rapid pathogen identification method. In this study, FLAT MS for direct from blood culture identification was evaluated and compared to FDA-cleared identification methods using the Benefit-risk Evaluation Framework (BED-FRAME) analysis. FLAT MS was evaluated and compared to Bruker Sepsityper and bioMérieux BioFire FilmArray BCID2 using results from a previous study. For this study, 301 positive blood cultures were collected from the University of Maryland Medical Center. The RDTs were compared by their sensitivities, time-to-results, hands-on time, and BED-FRAME analysis. The overall sensitivity of all platforms compared to culture results from monomicrobial-positive blood cultures was 88.3%. However, the three RDTs differed in their accuracy for identifying Gram-positive bacteria, Gram-negative bacteria, and yeast. Time-to-results for FLAT MS, Sepsityper, and BioFire BCID2 were all approximately one hour. Hands-on times for FLAT MS, Sepsityper, and BioFire BCID2 were 10 (±1.3), 40 (±2.8), and 5 (±0.25) minutes, respectively. BED-FRAME demonstrated that each RDT had utility at different pathogen prevalence and relative importance. BED-FRAME is a useful tool that can used to determine which RDT is best for a healthcare center.

Optimized Antibiotic Management of Critically Ill Patients with Severe Pneumonia Following Multiplex Polymerase Chain Reaction Testing: A Prospective Clinical Exploratory Trial

Molecular diagnostic testing is assumed to enable fast respiratory pathogen identification and contribute to improved pneumonia management. We set up a prospective clinical trial at a tertiary hospital intensive care unit including adult patients suspected of severe pneumonia from whom a lower respiratory tract sample could be obtained. During control periods (CPs), routine testing was performed, and during intervention periods (IPs), this testing was completed with the FilmArray Pneumonia Panel plus test (FA-PNEU) executed 24/7. The main objective was to measure the impact of FA-PNEU results in terms of reduced time to targeted antimicrobial treatment administration. Over a 10-month period, analysis was performed on 35 CP and 50 IP patients. The median time to targeted antimicrobial treatment administration was reduced to 4.3 h in IPs compared to 26.4 h in CPs, with 54% of IP patients having FA-PNEU results that led to a treatment modification, of which all but one were targeted. Modifications included 10 (37%) de-escalations, 7 (25.9%) escalations, 3 (11.1%) regimen switches, and 7 (25.9%) complete antimicrobial discontinuations. FA-PNEU results were available with a 42.3 h gain compared to routine identification. This prospective study confirmed retrospective data demonstrating the benefit of FA-PNEU testing in severe pneumonia management of critically ill patients through improved antimicrobial use.

Implementation of a pharmacy-driven rapid bacteremia response program

PURPOSE

This report describes a comprehensive pharmacy-driven rapid bacteremia response program.

SUMMARY

This novel program positioned the pharmacy department at a large, community health system to receive and respond to critical microbiologic diagnostic testing results, 24/7/365. The program empowered pharmacists to provide centralized, comprehensive care including assessing blood culture Gram stain results, adjusting antibiotic therapy per protocol, ordering repeat blood cultures, analyzing and interpreting rapid molecular diagnostic test results, placing orders for contact isolation, and communicating antibiotic recommendations to the treatment team. In the first year after program implementation, 2,282 blood culture Gram stains and 2,046 rapid diagnostic test results were called in to the pharmacy department. The program reduced the median time to effective therapy in patients who did not already have active antimicrobial orders from over 10 hours to less than 1 hour. Based on the Gram stain results, antibiotics were started per protocol in 34.2% of patients. Based on the rapid molecular diagnostic test results, adjustments were made to antibiotic regimens in 55.7% of cases after discussion with a provider. Of these adjustments, 39.9% were for escalation of antibiotics and 37.7% were for de-escalation of antibiotics.

CONCLUSION

By expanding the scope of pharmacy practice, barriers to optimizing clinical care were overcome.

Molecular antimicrobial susceptibility testing in sepsis

Rapidly detecting and identifying pathogens is crucial for appropriate antimicrobial therapy in patients with sepsis. Conventional diagnostic methods have been a great asset to medicine, though they are time consuming and labor intensive. This work will enable healthcare professionals to understand the bacterial community better and enhance their diagnostic capacity by using novel molecular methods that make obtaining quicker, more precise results possible. The authors discuss and critically assess the merits and drawbacks of molecular testing and the added value of these tests, including the shift turnaround time, the implication for clinicians' decisions, gaps in knowledge, future research directions and novel insights or innovations. The field of antimicrobial molecular testing has seen several novel insights and innovations to improve the diagnosis and management of infectious diseases.

Clinical and Microbiological Impact of Implementing a Decision Support Algorithm through Microbiologic Rapid Diagnosis in Critically Ill Patients: An Epidemiological Retrospective Pre-/Post-Intervention Study

BACKGROUND

Data on the benefits of rapid microbiological testing on antimicrobial consumption (AC) and antimicrobial resistance patterns (ARPs) are scarce. We evaluated the impact of a protocol based on rapid techniques on AC and ARP in intensive care (ICU) patients.

METHODS

A retrospective pre- (2018) and post-intervention (2019-2021) study was conducted in ICU patients. A rapid diagnostic algorithm was applied starting in 2019 in patients with a lower respiratory tract infection. The incidence of nosocomial infections, ARPs, and AC as DDDs (defined daily doses) were monitored.

RESULTS

A total of 3635 patients were included: 987 in the pre-intervention group and 2648 in the post-intervention group. The median age was 60 years, the sample was 64% male, and the average APACHE II and SOFA scores were 19 points and 3 points. The overall ICU mortality was 17.2% without any differences between the groups. An increase in the number of infections was observed in the post-intervention group (44.5% vs. 17.9%, p < 0.01), especially due to an increase in the incidence of ventilator-associated pneumonia (44.6% vs. 25%, p < 0.001). AC decreased from 128.7 DDD in 2018 to 66.0 DDD in 2021 (rate ratio = 0.51). An increase in Pseudomonas aeruginosa susceptibility of 23% for Piperacillin/tazobactam and 31% for Meropenem was observed.

CONCLUSION

The implementation of an algorithm based on rapid microbiological diagnostic techniques allowed for a significant reduction in AC and ARPs without affecting the prognosis of critically ill patients.

Assessment of the impact of centralized bioMérieux BACT/ALERT® VIRTUO® blood culture system (VIRTUO) implementation on outcomes in patients with gram-negative bacteremia

BACKGROUND

We evaluated pre- and postimplementation of Virtuo on outcome in patients with gram-negative bacteremia using a quasiexperimental time-in-motion design.

METHODS

Becton Dickinson BACTEC™ 9000 series (Bactec) (2018) and Virtuo system (2020) were utilized in a decentralized and centralized process, respectively. Data collected in August-December in 2018 and 2020 were analyzed with SPSS (ver 28).

RESULTS

For 185 patients in each time period, patient age, gender, length of hospitalization were not different. However, blood culture (BC) volume was significantly lower in 2020 (7.1 ± 2.6 mL) compared to 2018 (8.9 ± 1.9 mL). Time from BC draw and time from pathogen identification (ID) to treatment change were both significantly faster in 2020 (52.9 ± 38.3 hours; 15.1 ± 27.4 hours), compared to 2018 (65.0 ± 46.3 hours; 23.8 ± 33.8), respectively.

CONCLUSIONS

Replacement of decentralized Bactec with centralized Virtuo, resulted in significant improvement in management of patients gram-negative bacteremia.

Rapid antimicrobial resistance detection methods for bloodstream infection in solid organ transplantation: Proposed clinical guidance, unmet needs, and future directions

Recent advances in antimicrobial resistance detection have spurred the development of multiple assays that can accurately detect the presence of bacterial resistance from positive blood cultures, resulting in faster institution of effective antimicrobial therapy. Despite these advances, there are limited data regarding the use of these assays in solid organ transplant (SOT) recipients and there is little guidance on how to select, implement, and interpret them in clinical practice. We describe a practical approach to the implementation and interpretation of these assays in SOT recipients using the best available data and expert opinion. These findings were part of a consensus conference sponsored by the American Society of Transplantation held on December 7, 2021 and represent the collaboration between experts in transplant infectious diseases, pharmacy, antimicrobial and diagnostic stewardship, and clinical microbiology. Areas of unmet need and recommendations for future investigation are also presented.

Clinical Impact of Rapid Bacterial Microbiological Identification with the MALDI-TOF MS

Rapid microbiological reports to clinicians are related to improved clinical outcomes. We conducted a 3-year quasi-experimental design, specifically a pretest-posttest single group design in a university medical center, to evaluate the clinical impact of rapid microbiological identification information using MALDI-TOF MS on optimizing antibiotic prescription. A total of 363 consecutive hospitalized patients with bacterial infections were evaluated comparing a historical control group (CG) (n = 183), in which the microbiological information (bacterial identification and antibiotic susceptibility) was reported jointly to the clinician between 18:00 h and 22:00 h of the same day and a prospective intervention group (IG) (n = 180); the bacterial identification information was informed to the clinician as soon as it was available between 12:00 h and 14:00 h and the antibiotic susceptibility between 18:00 h and 22:00 h). We observed, in favor of IG, a statistically significant decrease in the information time (11.44 h CG vs. 4.48 h IG (p < 0.01)) from the detection of bacterial growth in the culture medium to the communication of identification. Consequently, the therapeutic optimization was improved by introducing new antibiotics in the 10-24 h time window (p = 0.05) and conversion to oral route (p = 0.01). Additionally, we observed a non-statistically significant decrease in inpatient mortality (global, p = 0.15; infection-related, p = 0.21) without impact on hospital length of stay. In conclusion, the rapid communication of microbiological identification to clinicians reduced reporting time and was associated with early optimization of antibiotic prescribing without worsening clinical outcomes.

Key considerations, target product profiles, and research gaps in the application of infrared spectroscopy and artificial intelligence for malaria surveillance and diagnosis

Studies on the applications of infrared (IR) spectroscopy and machine learning (ML) in public health have increased greatly in recent years. These technologies show enormous potential for measuring key parameters of malaria, a disease that still causes about 250 million cases and 620,000 deaths, annually. Multiple studies have demonstrated that the combination of IR spectroscopy and machine learning (ML) can yield accurate predictions of epidemiologically relevant parameters of malaria in both laboratory and field surveys. Proven applications now include determining the age, species, and blood-feeding histories of mosquito vectors as well as detecting malaria parasite infections in both humans and mosquitoes. As the World Health Organization encourages malaria-endemic countries to improve their surveillance-response strategies, it is crucial to consider whether IR and ML techniques are likely to meet the relevant feasibility and cost-effectiveness requirements-and how best they can be deployed. This paper reviews current applications of IR spectroscopy and ML approaches for investigating malaria indicators in both field surveys and laboratory settings, and identifies key research gaps relevant to these applications. Additionally, the article suggests initial target product profiles (TPPs) that should be considered when developing or testing these technologies for use in low-income settings.

Stewardship-Guided T2Candida Testing Shortens Time to Antifungal Treatment and Reduces Antifungal Usage Among Medical Intensive Care Unit Patients With Septic Shock

Background

Diagnosis of invasive candidiasis (IC) is limited by insensitivity and slow turnaround of cultures. Our objectives were to define the performance of T2Candida, a nonculture test, under guidance of a diagnostic stewardship program, and evaluate impact on time to antifungal initiation and antifungal utilization.

Methods

This was a retrospective study of adult medical intensive care unit (MICU) patients with septic shock for whom T2Candida testing was performed from March 2017 to March 2020. Patients with positive T2Candida results during this period were compared to MICU patients who did not undergo T2Candida testing but had septic shock and blood cultures positive for Candida from January 2016 through March 2020.

Results

Overall, 155 T2Candida tests from 143 patients were included. Nine percent of T2Candida tests were positive compared to 4.5% of blood cultures. Sensitivity, specificity, positive predictive value, and negative predictive value of T2Candida for proven and probable IC were 78%, 95%, 50%, and 99%, respectively. Patients who tested positive for T2Candida (n = 14) were diagnosed earlier and initiated on antifungal therapy sooner than patients with IC (n = 14) diagnosed by blood culture alone (median, 5.6 vs 60 hours; P < .0001). Median antifungal days of therapy/1000 patient-days were 23.3/month preimplementation and 15/month postimplementation (P  = .007). Following a negative T2Candida result, empiric antifungals were either not administered in 58% or discontinued within 72 hours in 96% of patients.

Conclusions

Diagnostic stewardship guided T2Candida testing resulted in reduced time to IC diagnosis, faster initiation of antifungal therapy, and lower antifungal usage among MICU patients with septic shock.

Identification of microorganisms by a rapid PCR panel from positive blood cultures leads to faster optimal antimicrobial therapy - a before-after study

BACKGROUND

The BioFire® FilmArray® Blood Culture Identification Panel 1 (BF-FA-BCIP) detects microorganisms with high accuracy in positive blood cultures (BC) - a key step in the management of patients with suspected bacteraemia. We aimed to compare the time to optimal antimicrobial therapy (OAT) for the BF-FA-BCIP vs. standard culture-based identification.

METHODS

In this retrospective single-centre study with a before-after design, 386 positive BC cases with identification by BF-FA-BCIP were compared to 414 controls with culture-based identification. The primary endpoint was the time from BC sampling to OAT. Secondary endpoints were time to effective therapy, length of stay, (re-)admission to ICU, in-hospital and 30-day mortality. Outcomes were assessed using Cox proportional hazard models and logistic regressions.

RESULTS

Baseline characteristics of included adult inpatients were comparable. Main sources of bacteraemia were urinary tract and intra-abdominal infection (19.2% vs. 22.0% and 16.8% vs. 15.7%, for cases and controls, respectively). Median (95%CI) time to OAT was 25.5 (21.0-31.2) hours with BF-FA-BCIP compared to 45.7 (37.7-51.4) hours with culture-based identification. We observed no significant difference for secondary outcomes.

CONCLUSIONS

Rapid microorganism identification by BF-FA-BCIP was associated with a median 20-h earlier initiation of OAT in patients with positive BC. No impact on length of stay and mortality was noted.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT04156633, registered on November 5, 2019.

Procalcitonin and Risk Prediction for Diagnosing Bacteremia in Hospitalized Patients: A Retrospective, National Observational Study

Bacteremia is associated with significant morbidity and mortality. Timely, appropriate therapy may improve clinical outcomes, and therefore, determining which patients benefit from more comprehensive diagnostic strategies (i.e., direct specimen testing) could be of value. We performed an assessment of procalcitonin (PCT) and clinical characteristics in the discrimination of bacteremic hospitalizations. We analyzed 71,105 encounters and 14,846 visits of patients with bacteremia alongside 56,259 without an admission. The area under the receiver-operating characteristic (AUROC) curve for the prediction of bacteremia via procalcitonin was 0.782 (95% CI 0.779-0.787). The prediction modeling of clinical factors with or without PCT resulted in a similar performance to PCT alone. However, the clinically predicted risk of bacteremia stratified by PCT thresholds allowed the targeting of high-incidence bacteremia groups (e.g., ≥50% positivity). The combined use of PCT and clinical characteristics could be useful in diagnostic stewardship by targeting further advanced diagnostic testing in patients with a high predicted probability of bacteremia.

The Interventions and Challenges of Antimicrobial Stewardship in the Emergency Department

Over the last decades, we have witnessed a constant increase in infections caused by multi-drug-resistant strains in emergency departments. Despite the demonstrated effectiveness of antimicrobial stewardship programs in antibiotic consumption and minimizing multi-drug-resistant bacterium development, the characteristics of emergency departments pose a challenge to their implementation. The inclusion of rapid diagnostic tests, tracking microbiological results upon discharge, conducting audits with feedback, and implementing multimodal educational interventions have proven to be effective tools for optimizing antibiotic use in these units. Nevertheless, future multicenter studies are essential to determine the best way to proceed and measure outcomes in this scenario.

Short incubation of disc diffusion for Streptococcus pneumoniae and Haemophilus influenzae to reduce time to susceptibility report

BACKGROUND

Rapidly instituted antimicrobial therapy is important in severe infections, and reduced time to the antimicrobial susceptibility testing (AST) report is thus of importance. Disc diffusion (DD) is a cheap, rapidly adaptable, flexible and comprehensive method for phenotypic AST. Previous studies have shown that early reading of inhibition zones for non-fastidious species is possible.

OBJECTIVES

To evaluate zone reading after short incubation of DD in Haemophilus influenzae (n = 73) and Streptococcus pneumoniae (n = 112).

METHODS

The readability was evaluated and susceptibility interpretation (SIR) was performed, using the EUCAST 18 ± 2 h incubation breakpoint table (version 12.0), after 6 and 8 h of incubation. Categorical agreement (CA) and error rates were calculated using standard DD and broth microdilution as reference.

RESULTS

The proportion of readable zones in H. influenzae was 19% (6 h) and 89% (8 h). The CA was 98% after 8 h. The corresponding readability in S. pneumoniae was 63%/98% and CA was 95%/97% after 6 and 8 h, respectively. Early reading of the screening discs (benzylpenicillin 1 unit in H. influenzae and oxacillin 1 µg in S. pneumoniae) correctly identified 18/22 of the H. influenzae isolates and all the readable S. pneumoniae isolates with reduced β-lactam susceptibility. For non-β-lactam agents, very major errors were most common for quinolones in S. pneumoniae. Introduction of areas of technical uncertainty (ATUs) reduced the error rate to ≤1.1%.

CONCLUSIONS

We conclude that shortened incubation is feasible for H. influenzae and S. pneumoniae. To reduce the risk of false categorization a buffer zone (i.e. ATU) near the breakpoints must be used.

Evaluation of the feasibility of EUCAST RAST using antimicrobial disks available in Japan

BACKGROUND

In November 2018, the European Committee for Antimicrobial Susceptibility Testing (EUCAST) established rapid antimicrobial susceptibility testing (RAST), which could be performed directly on positive blood culture samples. Although concentrations of antimicrobial agents in several antimicrobial disks available in Japan are different from those recommended by the EUCAST, the feasibility of EUCAST RAST using antimicrobial disks available in Japan remains to be evaluated.

METHODS

Blood culture bottles spiked with 127 clinical isolates (65 Escherichia coli and 62 Klebsiella pneumoniae) were tested by RAST for cefotaxime (CTX), ceftazidime (CAZ), meropenem, and ciprofloxacin using antimicrobial disks available in Japan, and compared with a reference AST method using automated AST instrument (VITEK®2).

RESULTS

The overall category agreement (CA) for RAST using antimicrobial disks available in Japan was 96.3%, 96.8%, and 95.6% after 4, 6, and 8 h of incubations, respectively. However, the CAZ RAST for E. coli showed major error of 8.2% (8 h incubation) for the Sensi disk, 14.3% (6 h incubation), and 24.5% (8 h incubation) for the KB disk. The CTX RAST for K. pneumoniae showed 25% (4 h incubation) and 31.3% (4 h incubation) of very major error for the Sensi and KB disks, respectively.

CONCLUSIONS

The EUCAST RAST results for E. coli and K. pneumoniae using antimicrobial disks available in Japan suggest their usefulness, although modified RAST breakpoints are required for several antimicrobial agents.

[Optimization in the detection of bacteremia: Integrated use of FilmArray (BCID2) and MALDI-TOF]

The usefulness of the combined use of MALDI-TOF MS from a subculture with 3-5h of incubation and the BCID2 panel (FilmArray) for the identification of microorganisms from positive blood cultures and its importance in the adjustment of antimicrobial therapy was analyzed. Overall identification with BCID2 was 90.4% (142/157) and with Maldi-TOF MS 83.4% (131/157) (p=0.0858); in 23 polymicrobial episodes (47 strains), the BCID2 panel identified 45 (95.7%) and MALDI-TOF MS 24 (51.1%) (p<0.0000). BCID2 detected the presence of the resistance genes mecA/C (n=16), blaKPC (n=8); blaCTX-M (n=17), blaNDM (n=8), blaOXA-48 (n=1), and vanA/B (n=2). The median time to report a result was 2.0h for BCID2 and 4.0h for MALDI-TOF MS (p<0.0000). Of 124 episodes analyzed, the rapid result of BCID2 led to 82.3% (102/124) therapeutic changes.

Potential impact of real-time processing and rapid susceptibility testing of blood samples in Gram-negative bloodstream infections in intensive care patients

INTRODUCTION

Timely and appropriate therapy is critical in patients with Gram-negative bloodstream infections (GNBSI). Most bacteriology laboratories process blood specimen in the daytime, during laboratory operating hours, and use conventional culture for antimicrobial susceptibility testing (AST). We simulated the potential impact of real-time processing and rapid AST (7 hours) on early adaptation of the antibiotic regimen in intensive care unit (ICU) patients with GNBSI.

METHODS

All GNBSI episodes occurring in the ICUs of 2 hospitals in Paris were included. Data were collected. For each episode of bacteremia, we simulated the impact of three strategies: (1) Real-time processing coupled with conventional techniques (Gram stain and standard AST); (2) Standard processing coupled with rapid AST; and (3) Real-time processing coupled with rapid AST.

RESULTS

We included 109 episodes in 98 patients. Forty-two patients (48%) died during ICU stay. AST results led to a change of the antibiotic regimen in 66 (61%) episodes, mainly de-escalation (54/109, 55%). In standard care, median time from sample collection to definitive AST result was 65.9 hours (±26.7). The three strategies would have reduced time-to-result by 9.2 hours (±7.1), 30.8 hours (±19.7) and 40.0 hours (±20.6) respectively. Compared to standard care, strategies 1, 2 and 3 would have avoided 20, 69 and 90 patient-days of broad-spectrum antibiotics respectively.

CONCLUSION

In addition to real-time processing of blood samples, rapid AST would be the most effective strategy to shorten time-to-result in critical patients with GNBSI.

Incidence, microbiological and immunological characteristics of ventilator-associated pneumonia assessed by bronchoalveolar lavage and endotracheal aspirate in a prospective cohort of COVID-19 patients: CoV-AP study

BACKGROUND

No univocal recommendation exists for microbiological diagnosis of ventilator-associated pneumonia (VAP). Sampling of either proximal or distal respiratory tract likely impacts on the broad range of VAP incidence between cohorts. Immune biomarkers to rule-in/rule-out VAP diagnosis, although promising, have not yet been validated. COVID-19-induced ARDS made VAP recognition even more challenging, often leading to overdiagnosis and overtreatment. We evaluated the impact of different respiratory samples and laboratory techniques on VAP incidence and microbiological findings in COVID-19 patients.

METHODS

Prospective single-centre cohort study conducted among COVID-19 mechanically ventilated patients in Policlinico Hospital (Milan, Italy) from January 2021 to May 2022. Microbiological confirmation of suspected VAP (sVAP) was based on concomitant endotracheal aspirates (ETA) and bronchoalveolar lavage (BAL). Conventional and fast microbiology (FILMARRAY® Pneumonia Panel plus, BALFAPPP) as well as immunological markers (immune cells and inflammatory cytokines) was analysed.

RESULTS

Seventy-nine patients were included. Exposure to antibiotics and steroid therapy before ICU admission occurred in 51/79 (64.6%) and 60/79 (65.9%) patients, respectively. Median duration of MV at VAP suspicion was 6 (5-9) days. Incidence rate of microbiologically confirmed VAP was 33.1 (95% CI 22.1-44.0) and 20.1 (95% CI 12.5-27.7) according to ETA and BAL, respectively. Concordance between ETA and BAL was observed in 35/49 (71.4%) cases, concordance between BALFAPPP and BAL in 39/49 (79.6%) cases. With BAL as reference standard, ETA showed 88.9% (95% CI 70.8-97.7) sensitivity and 50.0% (95% CI 28.2-71.8) specificity (Cohen's Kappa 0.40, 95% CI 0.16-0.65). BALFAPPP showed 95.0% (95% CI 75.1-99.9) sensitivity and 69% (95% CI 49.2-84.7) specificity (Cohen's Kappa 0.60, 95% CI 0.39-0.81). BAL IL-1β differed significantly between VAP (135 (IQR 11-450) pg/ml) and no-VAP (10 (IQR 2.9-105) pg/ml) patients (P = 0.03).

CONCLUSIONS

In COVID-19 ICU patients, differences in microbial sampling at VAP suspicion could lead to high variability in VAP incidence and microbiological findings. Concordance between ETA and BAL was mainly limited by over 20% of ETA positive and BAL negative samples, while BALFAPPP showed high sensitivity but limited specificity when evaluating in-panel targets only. These factors should be considered when comparing results of cohorts with different sampling. BAL IL-1β showed potential in discriminating microbiologically confirmed VAP.

CLINICAL TRIAL REGISTRATION

NCT04766983, registered on February 23, 2021.

Information Delay of Significant Bloodstream Isolates and Patient Mortality: A Retrospective Analysis of 6225 Adult Patients With Bloodstream Infections

BACKGROUND

Our aim in this study was to evaluate the clinical and prognostic impact of communicating microbiological information in real time for adult patients with bloodstream infections (BSIs).

METHODS

We retrospectively reviewed 6225 clinical episodes of bacteremia in a teaching hospital from January 2013 to December 2019. Bacteremia-associated mortality was compared when blood culture results were relayed to the infectious diseases specialist (IDS) in real time and periods when results were relayed the following morning. The impact of information availability using mortality at 30 days was used as the main outcome of the study.

RESULTS

The initial analysis (all microorganisms included) did not show an association of mortality and information delay to the IDS (odds ratio [OR], 1.18; 95% confidence interval [CI], .99-1.42). However, information delay of BSIs caused by fast-growing microorganisms such as Enterobacterales was associated with a significant increase in the odds of death at 30 days both in the univariate (OR, 1.76; 95% CI, 1.30-2.38) and multivariate analysis (OR, 2.22; 95% CI, 1.50-3.30). Similar results were found with mortality at 14 days and 7 days in the univariate (OR, 1.54; 95% CI, 1.08-2.20 and OR, 1.56; 95% CI, 1.03-2.37, respectively) and the multivariate analysis (OR, 2.05; 95% CI, 1.27-3.32 and OR, 1.92; 95% CI, 1.09-3.40, respectively).

CONCLUSIONS

Information delivered in real time has prognostic relevance and is likely to improve survival of patients with documented BSIs. Future studies should address the prognostic impact of adequate resource allocation (microbiologist/IDS with 24/7 coverage) in BSIs.

Improving the Efficiency of Antimicrobial Stewardship Action in Acute Care Facilities

Inpatient antimicrobial stewardship (AS) programs are quality improvement programs tasked with improving antibiotic practices by augmenting frontline providers' antibiotic prescription. Prospective audit and feedback (PAF) and preauthorization (PRA) are essential activities in the hospital that can be resource intensive for AS teams. Improving efficiency in AS activities is needed when there are limited resources or when programs are looking to expand tasks beyond PAF and PRA, such as broad education or guideline development. Guidance on the creation and maintenance of alerts for the purpose of PAF reviews, modifications of antibiotic restrictions for PRA polices, and overall initiative prioritization strategies are reviewed. In addition, daily prioritization tools, such as the tiered approach, scoring systems, and regression modeling, are available for stewards to prioritize their daily workflow. Using these tools and guidance, AS programs can be productive and impactful in the face of resource limitation or competing priorities in the hospital.

Epidemiology, Resistance Profiles, and Outcomes of Bloodstream Infections in Community-Onset Sepsis in the United States

OBJECTIVES

To describe frequency of positive blood cultures, patterns of pathogens' characteristics and their resistance profile in patients with blood cultures drawn due to a presumed diagnosis of community-onset sepsis, and to examine the association between blood culture-positive pathogens and hospital mortality.

DESIGN

Retrospective cohort study.

SETTING

Two hundred one U.S. hospitals from 2016 to 2020 using the Premier Healthcare Database.

SUBJECTS

Adult patients presenting with community-onset sepsis who had blood cultures collected within 2 days of hospital admission. We defined sepsis using the U.S. Centers for Disease Control Adult Sepsis Event Surveillance criteria.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We identified 147,061 patients with community-onset sepsis. The number of blood culture-positive sepsis episodes was 21,167 (14%) and the number of nonblood culture-positive sepsis episodes was 20,326 (14%). Among patients with blood culture-positive sepsis, Gram-negative rods were isolated in 55% of patients, Gram-positive cocci were isolated in 47%. Of those, methicillin-resistant Staphylococcus aureus (MRSA) was 11%, ceftriaxone-resistant Enterobacterales /extended-spectrum β-lactamase was 7%, and carbapenem-resistant Enterobacterales was 1.3%. The crude in-hospital mortality was 17% for culture-negative sepsis, 13% for nonblood culture-positive sepsis, and 17% for blood culture-positive sepsis. In multilevel logistic regression models, compared with culture-negative sepsis, blood culture-positive sepsis (adjusted odds ratio [aOR], 0.89; 95% CI, 0.85-0.94) and nonblood culture-positive sepsis (aOR, 0.82; 95% CI, 0.78-0.87) were associated with lower odds of in-hospital mortality. Acinetobacter species, Pseudomonas aeruginosa , methicillin-sensitive Staphylococcus aureus , and MRSA were associated with higher in-hospital mortality, whereas Escherichia coli , Klebsiella species, Proteus species, and Streptococcus species were associated with lower in-hospital mortality.

CONCLUSIONS

In patients hospitalized with community-onset sepsis, the prevalence of blood culture-positive sepsis was 14%. Among positive blood culture sepsis resistant organisms were infrequent. Compared with culture-negative sepsis, blood culture-positive sepsis and nonblood culture-positive sepsis were associated with lower in-hospital mortality.

Understanding and Implementing Diagnostic Stewardship: A Guide for Resident Physicians in the Era of Antimicrobial Resistance

Antimicrobial resistance (AMR) poses a significant global health challenge, exacerbated by the COVID-19 pandemic. Antimicrobial stewardship programs (ASPs) are crucial in managing this crisis, with diagnostic stewardship (DS) emerging as a key component. DS refers to the appropriate use of diagnostic tests to optimize patient outcomes, improve antimicrobial use, and combat multi-drug-resistant (MDR) organisms. Despite its potential, understanding and application of DS remain ambiguous in multiple respects, which, however, do not directly implicate the implementation of such initiatives. DS is particularly important for resident physicians who are often at the forefront of patient care and can significantly influence future AMR strategies. This review provides a comprehensive overview of DS, discussing its importance, potential challenges, and future directions. It emphasizes the need for resident physicians to understand DS principles and integrate them into their clinical practice from the beginning of their careers. The review also highlights the role of various stakeholders in implementing DS and the importance of continuous education and training. Ultimately, DS is not just a clinical tool but a philosophy of care, essential for a more responsive, humane, and effective healthcare system.

Bloodstream Infections: Comparison of Diagnostic Methods and Therapeutic Consequences between a Hospital in a Resource-Limited Setting and Two French Hospitals

In recent years, the diagnosis of bloodstream infections has been complemented by rapid microbiological methods, unattainable to most clinical laboratories in resource-limited settings. We evaluated the impact of their shortage on antibiotic therapy adequacy. We conducted a prospective multicenter cohort study including 150 adult Gram-negative bacilli bacteremia episodes, evenly distributed across three university hospitals: one in Lebanon, a resource-limited setting, and two in France, a resource-rich setting. Previous colonization by multidrug-resistant organisms (MDRO) was significantly more prevalent among the Lebanese than the French group of patients (16/50 vs. 5/100; p < 0.01). Bloodstream infections by carbapenemase-producing Enterobacterales and other MDRO were higher among the Lebanese than the French group of patients (25/50 vs. 12/100; p < 0.01). For the French group, rapid identification of species and mechanisms of resistance significantly shortened turnaround time for definitive laboratory diagnosis and increased antibiotic therapy adequacy. No statistically significant differences were noted in targeted antibiotic therapy between the two groups. This study suggests that, in settings where bacterial resistance is prevalent, rapid microbiological methods have not provided any additional value. The clinical and economic impact of rapid microbiological methods will likely depend on local CPE, VRE, and other MDRO epidemiology and are areas for future research.

From bottle to bedside: Implementation considerations and antimicrobial stewardship considerations for bloodstream infection rapid diagnostic testing

Antimicrobial stewardship (AMS) programs have been quick to adopt novel molecular rapid diagnostic technologies (mRDTs) for bloodstream infections (BSIs) to improve antimicrobial management. As such, most of the literature demonstrating the clinical and economic benefits of mRDTs for BSI is in the presence of active AMS intervention. Leveraging mRDTs to improve antimicrobial therapy for BSI is increasingly integral to AMS program activities. This narrative review discusses available and future mRDTs, the relationship between the clinical microbiology laboratory and AMS programs, and practical considerations for optimizing the use of these tools within a health system. Antimicrobial stewardship programs must work closely with their clinical microbiology laboratories to ensure that mRDTs are used to their fullest benefit while remaining cognizant of their limitations. As more mRDT instruments and panels become available and AMS programs continue to expand, future efforts must consider the expansion beyond traditional settings of large academic medical centers and how combinations of tools can further improve patient care.

Microbiological Assessment of the FilmArray Blood Culture Identification 2 Panel: Potential Impact in Critically Ill Patients

Rapid pathogen detection and characterization from positive blood cultures are crucial in the management of patients with bloodstream infections (BSI) and in achieving their improved outcomes. In this context, the FilmArray Blood Culture Identification (BCID2) panel is an FDA approved molecular test, which can quickly identify different species and resistance determinants, thus making an impact in antimicrobial practice. In this study, we analyzed 136 positive blood cultures collected from septic critically ill patients from April 2021 to March 2023 by using the FilmArray BCID2 panel, and results obtained by fast molecular analysis were compared to those obtained by routine protocols. Overall, the BCID2 panel showed a strong concordance with conventional methods, particularly in the case of monomicrobial samples, whereas some discrepancies were found in 10/32 polymicrobial samples. Of note, this technique allowed us to identify a significant number of yeasts (37/94 samples) and to unravel the presence of several resistance markers, including both Gram-positive and Gram-negative organisms. These findings strongly support the potential use of the BCID2 panel as an adjunct to the conventional microbiology methods for the management of critically ill septic patients, thus accelerating blood pathogen and resistance genes identification, focusing antibiotic therapy, and avoiding inappropriate and excessive use of drugs.