Impact of an Antimicrobial Stewardship Program-bundled initiative utilizing Accelerate Pheno™ system in the management of patients with aerobic Gram-negative bacilli bacteremia

Antibiotic stewardship bundle for uncomplicated gram-negative bacteremia at an academic health system: a quasi-experimental study

Objective

To evaluate whether an antimicrobial stewardship bundle (ASB) can safely empower frontline providers in the treatment of gram-negative bloodstream infections (GN-BSI).

Intervention and Method

From March 2021 to February 2022, we implemented an ASB intervention for GN-BSI in the electronic medical record (EMR) to guide clinicians at the point of care to optimize their own antibiotic decision-making. We conducted a before-and-after quasi-experimental pre-bundle (preBG) and post-bundle (postBG) study evaluating a composite of in-hospital mortality, infection-related readmission, GN-BSI recurrence, and bundle-related outcomes.

Setting

New York University Langone Health (NYULH), Tisch/Kimmel (T/K) and Brooklyn (BK) campuses, in New York City, New York.

Patients

Out of 1097 patients screened, the study included 225 adults aged ≥18 years (101 preBG vs 124 postBG) admitted with at least one positive blood culture with a monomicrobial gram-negative organism.

Results

There was no difference in the primary composite outcome (12.9% preBG vs. 7.3% postBG; P = 0.159) nor its individual components of in-hospital mortality, 30-day infection-related readmission, and GN-BSI recurrence. Vancomycin (VAN) discontinuation (DC) was done more frequently by the primary team in postBG (37.9% vs 66.7%; P < 0.001). In postBG, de-escalation done by the primary team increased by 8.8%, P = 0.310 and there was an 11.1% increase in the use of aminopenicillin-based antibiotics, P = 0.043.

Conclusions

GN-BSI bundle worked as a nudge-based strategy to guide providers in VAN DC and increased de-escalation to aminopenicillin-based antibiotics without negatively impacting patient outcomes.

Getting rapid diagnostic test data into the appropriate hands by leveraging pharmacy staff and a clinical surveillance platform: a case study from a US community hospital

OBJECTIVES

To outline the procedural implementation and optimization of rapid diagnostic test (RDT) results for bloodstream infections (BSIs) and to evaluate the combination of RDTs with real-time antimicrobial stewardship team (AST) support plus clinical surveillance platform (CSP) software on time to appropriate therapy in BSIs at a single health system.

METHODS

Blood culture reporting and communication were reported for four time periods: (i) a pre-BCID [BioFire® FilmArray® Blood Culture Identification (BCID) Panel] implementation period that consisted of literature review and blood culture notification procedure revision; (ii) a BCID implementation period that consisted of BCID implementation, real-time results notification via CSP, and creation of a treatment algorithm; (iii) a post-BCID implementation period; and (iv) a BCID2 implementation period. Time to appropriate therapy metrics was reported for the BCID2 time period.

RESULTS

The mean time from BCID2 result to administration of effective antibiotics was 1.2 h (range 0-7.9 h) and time to optimal therapy was 7.6 h (range 0-113.8 h) during the BCID2 Panel implementation period. When comparing time to optimal antibiotic administration among patients growing ceftriaxone-resistant Enterobacterales, the BCID2 Panel group (mean 2.8 h) was significantly faster than the post-BCID Panel group (17.7 h; P = 0.0041).

CONCLUSIONS

Challenges exist in communicating results to the appropriate personnel on the healthcare team who have the knowledge to act on these data and prescribe targeted therapy against the pathogen(s) identified. In this report, we outline the procedures for telephonic communication and CSP support that were implemented at our health system to distribute RDT data to individuals capable of assessing results, enabling timely optimization of antimicrobial therapy.

Evaluating the impact of rapid antimicrobial susceptibility testing for bloodstream infections: a review of actionability, antibiotic use and patient outcome metrics

Antimicrobial susceptibility testing (AST) is a core function of the clinical microbiology laboratory and is critical to the management of patients with bloodstream infections (BSIs) to facilitate optimal antibiotic therapy selection. Recent technological advances have resulted in several rapid methods for determining susceptibility direct from positive blood culture that can provide turnaround times in under 8 h, which is considerably shorter than conventional culture-based methods. As diagnostic results do not directly produce a medical intervention, actionability is a primary determinant of the effect these technologies have on antibiotic use and ultimately patient outcomes. Randomized controlled trials and observational studies consistently show that rapid AST significantly reduces time to results and improves antimicrobial therapy for patients with BSI across various methods, patient populations and organisms. To date, the clinical impact of rapid AST has been demonstrated in some observational studies, but randomized controlled trials have not been sufficiently powered to validate many of these findings. This article reviews various metrics that have been described in the literature to measure the impact of rapid AST on actionability, antibiotic exposure and patient outcomes, as well as highlighting how implementation and workflow processes can affect these metrics.

Combination of a Rapid Diagnostic Assay and Antimicrobial Stewardship Intervention for Gram-Negative Bacteremia

Background

Traditional blood cultures for gram-negative bacteremia can take up to 72 hours or more to return results, prolonging the duration of empiric broad-spectrum intravenous antibiotics. The Accelerate Pheno system provides rapid identification and susceptibilities for blood cultures in gram-negative bacteremia. Current data on its clinical utility are mixed overall, so the system requires further research.

Methods

A multicenter, retrospective quasi-experimental study was conducted comparing the Accelerate Pheno rapid diagnostic system with antimicrobial stewardship intervention and traditional blood cultures alone.

Results

A total of 264 patients with blood cultures with gram-negative bacteria growth were included in the final analysis (102 pre-intervention, 162 post-intervention). The antimicrobial stewardship team made 364 recommendations in 152/162 (93.8%) patients in the post group. Duration of intravenous therapy was shorter (P < .001) for the post-intervention group (median, 4.0 days) compared with the pre-intervention group (median, 7.5 days). Hospital length of stay was also shorter (P < .001) for the post-intervention group (median, 5.1 days) compared with the pre-intervention group (median, 7.0 days). Readmission rates within 30 days were reduced (P = .042) post-intervention (13.0%) compared with pre-intervention (22.6%). In the post-intervention group, a larger proportion of patients were transitioned to oral therapy at any point (126/162, 77.8%) compared with pre-intervention (62/102, 60.8%; P < .001).

Conclusions

These results suggest that the Accelerate Pheno system, with active review and intervention by a multidisciplinary antimicrobial stewardship team, is a useful tool in improving both patient-centric and antimicrobial stewardship outcomes.

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.

Antimicrobial Multidrug Resistance: Clinical Implications for Infection Management in Critically Ill Patients

The increasing incidence of antimicrobial resistance (AMR) worldwide represents a serious threat in the management of sepsis. Due to resistance to the most common antimicrobials prescribed, multidrug-resistant (MDR) pathogens have been associated with delays in adequate antimicrobial therapy leading to significant increases in mortality, along with prolonged hospital length of stay (LOS) and increases in healthcare costs. In response to MDR infections and the delay of microbiological results, broad-spectrum antibiotics are frequently used in empirical antimicrobial therapy. This can contribute to the overuse and misuse of antibiotics, further promoting the development of resistance. Multiple measures have been suggested to combat AMR. This review will focus on describing the epidemiology and trends concerning MDR pathogens. Additionally, it will explore the crucial aspects of identifying patients susceptible to MDR infections and optimizing antimicrobial drug dosing, which are both pivotal considerations in the fight against AMR. Expert commentary: The increasing AMR in ICUs worldwide makes the empirical antibiotic therapy challenging in septic patients. An AMR surveillance program together with improvements in MDR identification based on patient risk stratification and molecular rapid diagnostic tools may further help tailoring antimicrobial therapies and avoid unnecessary broad-spectrum antibiotics. Continuous infusions of antibiotics, therapeutic drug monitoring (TDM)-based dosing regimens and combination therapy may contribute to optimizing antimicrobial therapy and limiting the emergence of resistance.

Clinical impact of the accelerate PhenoTest® BC system on patients with gram-negative bacteremia and high risk of antimicrobial resistance: a prospective before-after implementation study

BACKGROUND

The Accelerate PhenoTest® BC system (AXDX) is a novel assay for rapid bacterial identification and antimicrobial susceptibility (AST). We report an evaluation of its impact on treatment of patients with Gram-negative bacteremia (GNB) with a high risk of antimicrobial resistance (AMR).

METHODS

A prospective single-center evaluation before and after implementation of AXDX in addition to standard-of-care (SOC) microbiology and antimicrobial stewardship program (ASP). Patients with GNB reported during laboratory working hours and prespecified risk factors for AMR were included. The primary outcome was an ASP-oriented beneficial antimicrobial change, defined as either an escalation of an inappropriate empiric treatment or de-escalation of a broad-spectrum treatment of a susceptible organism. Main secondary outcomes were time to an appropriate treatment, antimicrobial treatment duration, length of stay (LOS) and mortality.

RESULTS

Included were 46 and 57 patients in the pre- and post-intervention periods, respectively. The median time to an AST-oriented beneficial change was 29.2 h vs. 49.6 h, respectively (p < 0.0001). There were no significant differences in the time to appropriate treatment, LOS or mortality. Antimicrobial treatment duration was longer during the intervention period (10 vs. 8 days, p = 0.007). AXDX failed to correctly identify pathogens in all 6 cases of polymicrobial bacteremia. In two cases patient care was potentially compromised due to inappropriate de-escalation.

CONCLUSIONS

AXDX implementation resulted in a 20.4-hour shorter time to an ASP-oriented beneficial antimicrobial change. This should be weighed against the higher costs, the lack of other proven clinical benefits and the potential harm from mis-identification of polymicrobial bacteremias.

Mortality due to Multidrug-Resistant Gram-Negative Bacteremia in an Endemic Region: No Better than a Toss of a Coin

The incidence of multidrug-resistant (MDR) bloodstream infections (BSIs) is associated with high morbidity and mortality. Little evidence exists regarding the epidemiology of BSIs and the use of appropriate empirical antimicrobial therapy in endemic regions. Novel diagnostic tests (RDTs) may facilitate and improve patient management. Data were assessed from patients with MDR Gram-negative bacteremia at a university tertiary hospital over a 12-month period. In total, 157 episodes of MDR Gram-negative BSI were included in the study. The overall mortality rate was 50.3%. Rapid molecular diagnostic tests were used in 94% of BSI episodes. In univariate analysis, age (OR 1.05 (95% CI 1.03, 1.08) p < 0.001), Charlson Comorbidity Index (OR 1.51 (95% CI 1.25, 1.83) p < 0.001), procalcitonin ≥ 1(OR 3.67 (CI 95% 1.73, 7.79) p < 0.001), and monotherapy with tigecycline (OR 3.64 (95% CI 1.13, 11.73) p = 0.030) were the only factors associated with increased overall mortality. Surprisingly, time to appropriate antimicrobial treatment had no impact on mortality. MDR pathogen isolation, other than Klebsiella pneumoniae and Acinetobacter baumanii, was associated with decreased mortality (OR 0.35 (95% CI 0.16, 0.79) p = 0.011). In multivariate analysis, the only significant factor for mortality was procalcitonin ≥ 1 (OR 2.84 (95% CI 1.13, 7.11) p = 0.025). In conclusion, in an endemic area, mortality rates in MDR BSI remain notable. High procalcitonin was the only variable that predicted death. The use of rapid diagnostics did not improve mortality rate.

Rapid Diagnostic Test Value and Implementation in Antimicrobial Stewardship Across Low-to-Middle and High-Income Countries: A Mixed-Methods Review

Despite technological advancements in infectious disease rapid diagnostic tests (RDTs) and use to direct therapy at the per-patient level, RDT utilisation in antimicrobial stewardship programmes (ASPs) is variable across low-to-middle income and high-income countries. Key insights from a panel of seven infectious disease experts from Colombia, Japan, Nigeria, Thailand, the UK, and the USA, combined with evidence from a literature review, were used to assess the value of RDTs in ASPs. From this, a value framework is proposed which aims to define the benefits of RDT use in ASPs, separate from per-patient benefits. Expert insights highlight that, to realise the value of RDTs within ASPs, effective implementation is key; actionable advice for choosing an RDT is proposed. Experts advocate the inclusion of RDTs in the World Health Organization Model List of essential in vitro diagnostics and in iterative development of national action plans.

Usefulness of EUCAST rapid antibiotic susceptibility breakpoints and screening cut-off values directly from blood cultures for the inference of β-lactam resistance mechanisms in Enterobacterales

Background

Reducing the turnaround time for reporting antimicrobial susceptibility testing (AST) results is important for adjusting empirical treatments and may impact clinical outcomes of septic patients, particularly in settings with high antimicrobial resistance. Disc diffusion could be useful for inferring β-lactam resistance mechanisms.

Objectives

To evaluate the usefulness of EUCAST rapid AST (RAST) disc diffusion breakpoints for the screening of resistance mechanisms (sRAST) and interpretive reading of resistance phenotypes to infer ESBL and carbapenemases production in Enterobacterales.

Methods

Blood cultures were artificially spiked with Enterobacterales clinical isolates with well-characterized β-lactam resistance mechanisms (n = 93), WT phenotypes (n = 26) and ATCC strains (n = 8). AST was performed by disc diffusion directly from blood cultures and inhibition zones were manually measured at 4, 6 and 8 h. To infer the presence of resistance mechanisms, EUCAST RAST breakpoints and screening cut-off values (sRAST) combined with the double-disc synergy test (DDS) for ESBLs or aztreonam susceptibility for carbapenemases detection were used.

Results

DDS together with sRAST detected all ESBL producers as early as at 4 h incubation. Cefotaxime was the antibiotic with the highest discriminatory power. The suspicion of carbapenemase production by sRAST at 8 h was possible in 73% of Klebsiella pneumoniae and in 100% of Escherichia coli carbapenemase-producing isolates. Phenotypic analysis improves the detection of some low hydrolytic carbapenemases (OXA-48 or KPC-3 mutants).

Conclusions

Early detection of β-lactam resistance mechanisms directly from positive blood cultures was possible using sRAST together with the interpretive reading of antibiotic resistance phenotypes. Some carbapenemase types such as OXA-48 might be difficult to infer. Screening-positive isolates should be confirmed using an alternative technique.

Impact of phenotypic rapid diagnostic assay on duration of empiric antibiotics for gram-negative bacteremia

Objective

Rapid diagnostic tests (RDTs) are increasingly being implemented as antimicrobial stewardship tools to facilitate antibiotic modification and reduce complications related to their overutilization. We measured the clinical impact of a phenotypic RDT with antimicrobial stewardship (AMS) in the setting of gram-negative bacteremia.

Setting and participants

In this single-center retrospective cohort study, we evaluated adult patients with gram-negative bacteremia who received at least 72 hours of an antibiotic.

Methods

The primary outcome was the duration of empiric antibiotic therapy for gram-negative bacteremia. Secondary outcomes included time-to-directed therapy, proportion of modifications, hospital length of stay (LOS), and subsequent infection with a multidrug-resistant organism (MDRO) or C. difficile infection (CDI).

Results

The duration of empiric antibiotics decreased in the RDT+AMS group (4 days vs 2 days; P < .01). Time to directed therapy decreased from 75.0 to 27.9 hours (P < .01).

Conclusions

The clinical outcomes of LOS, MDRO, and CDI were reduced. The phenotypic RDT demonstrated an improvement in stewardship measures and clinical outcomes.

Evaluation of the Performance and Clinical Impact of a Rapid Phenotypic Susceptibility Testing Method Directly from Positive Blood Culture at a Pediatric Hospital

Bloodstream infection poses a significant medical emergency that necessitates timely administration of appropriate antibiotics. Standard laboratory workup for antimicrobial susceptibility testing (AST) involves subculture of organisms from positive blood bottles followed by testing using broth microdilution; however, this process can take several days. The Accelerate Pheno Blood Culture panel (Pheno) provides rapid phenotypic testing of selected Gram-negative organisms directly from positive blood cultures. This has the potential to shorten the AST process to several hours and impact time to antimicrobial optimization and subsequent clinical outcomes; however, these metrics have not been assessed in pediatric populations. We retrospectively compared two patient cohorts with blood cultures positive for on-panel Gram-negative organisms: 82 cases tested by conventional AST methods, and 80 cases postintervention at our pediatric hospital. Susceptibility testing from the Pheno yielded 91.5% categorical agreement with a broth microdilution-based reference method with 7.4% minor error, 1.1% major error, and 0.1% very major error rates. The median time from blood culture positivity to AST decreased from 20.0 h to 9.7 h (P < 0.001), leading to an overall decrease in time from blood culture positivity to change in therapy from 36.0 h to 25.0 h (P < 0.001). There was no observed change in length of stay or 30-day mortality. Median duration on meropenem decreased from 64.8 h to 31.6 h (P = 0.04). We conclude the Pheno had accurate performance and that implementation allowed for faster AST reporting, improved time to optimal therapy, and decreased duration on meropenem in children.

Impact of a laboratory developed phenotypic rapid susceptibility test directly from positive blood cultures on time to narrowest effective therapy in patients with Gram-negative bacteremia: a prospective randomized trial

Background

Antimicrobial susceptibility testing (AST) is often needed prior to antimicrobial optimization for patients with gram-negative bloodstream infections (GN-BSIs). Rapid AST (rAST) in combination with antimicrobial stewardship (AS) may decrease time to administration of narrower antibiotics.

Methods

This was a prospective, nonblinded, randomized trial evaluating the impact of a phenotypic rAST method vs conventional AST (cAST) in hospitalized patients with GN-BSI and source control. The primary outcome was time to narrowest effective therapy.

Results

Two hundred seventy-four patients were randomized and 205 underwent analysis (97 cAST, 108 rAST). Median (interquartile range [IQR]) time to susceptibility results was 23 hours shorter in the rAST group (cAST: 62 [59–67] hours vs rAST: 39 [IQR, 35–46] hours; P < .001). Median (IQR) time to narrowest effective therapy was similar between groups (cAST: 73 [44–138] hours vs rAST: 64 [42–92] hours; P = .10). Median (IQR) time to narrowest effective therapy was significantly shorter in a prespecified subgroup of patients not initially on narrowest therapy and during AS working hours (cAST: 93 [56–154] hours vs rAST: 62 [43–164] hours; P = .004). Significant decreases were observed in median (IQR) time to oral therapy (cAST: 126 [76–209] hours vs rAST: 91 [66–154] hours; P = .02) and median (IQR) length of hospital stay (cAST: 7 [4–13] days vs rAST: 5 [4–8] days; P = .04).

Conclusions

In patients with GN-BSI, rAST did not significantly decrease time to narrowest effective therapy but did decrease time to oral antibiotics and length of hospital stay. Rapid AST using existing microbiology platforms has potential to optimize patient outcomes.

Impact of Rapid Susceptibility Testing System on the Management of Gram-Negative Bacteremia in a Network of Community Hospitals

BACKGROUND

Rapid initiation of optimal antimicrobial therapy is crucial for the management of Gram-negative (GN) bacteremia. We aimed to evaluate the impact of Accelerate PhenoTM (AxDx) system on change in therapy and length of stay among patients with GN bacteremia.

METHODS

We conducted a retrospective cohort study of adult patients hospitalized who had at least 1 blood culture with presence of Enterobacterales. We compared clinical outcomes among patients who had their blood cultures processed through standard methods alone vs AxDx.

RESULTS

We identified 255 bacteremia episodes among 243 unique patients. In the AxDx group, 31.1% of patients had deescalation of antibiotics within 48 h from blood culture collection compared to 20.0% of patients in the control group (P = 0.09). We found no impact of AxDx on the odds of deescalation at 48 h from blood culture collection [odds ratio (OR) 1.80 (95% CI 0.91-3.56), P = 0.09] or Gram stain report [OR 1.61 (95% CI 0.86-3.01), P = 0.14]. Escalation in therapy at 48 h from blood culture collection occurred in 16.8% and 16.9% of patients in the AxDx and control groups, respectively (P = 0.99). There was no impact on the odds of escalation at 48 h from blood culture collection [OR 0.99 (95% CI 0.47-2.11), P = 0.99] or Gram stain report [OR 1.26 (95% CI 0.57-2.80), P = 0.57]. No differences were seen in length of stay and mortality between the 2 groups.

CONCLUSIONS

The impact of rapid identification and susceptibility technologies may differ according to the setting in which they are implemented.