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

Antimicrobial Stewardship Interventions to Combat Antibiotic Resistance: an Update on Targeted Strategies

PURPOSE OF REVIEW

Overutilization of antimicrobials is a known contributor to the development of antimicrobial resistance, which is a threat to global health. The goal of antimicrobial stewardship programs (ASPs) is to implement targeted interventions to reduce inappropriate antimicrobial prescribing and prevent development of antimicrobial resistance. We aim to review recently published literature focused on five categories of ASP interventions that have demonstrated success in optimizing appropriate antimicrobial use, improving patient outcomes, and fighting antimicrobial resistance.

RECENT FINDINGS

In the past year, ASP interventions in the published literature have focused on minimizing duration of antimicrobial therapy for infectious syndromes, implementing novel methods for performing prospective audit and feedback, utilizing microbiology laboratory or rapid diagnostic tests to expedite diagnosis, leveraging clinical decision support and electronic medical record tools, and performing penicillin allergy assessment. While the majority of studies assessing ASP interventions do not assess changes in antimicrobial resistance, outcomes demonstrating improved appropriate antibiotic use have been used as a surrogate. Successful ASPs should seek to implement and evaluate novel interventions targeting improvement in antimicrobial prescribing. Such interventions are of critical importance to prevent further growth of antimicrobial resistance.

Clinical Utility of Advanced Microbiology Testing Tools

Advanced microbiology technologies are rapidly changing our ability to diagnose infections, improve patient care, and enhance clinical workflow. These tools are increasing the breadth, depth, and speed of diagnostic data generated per patient, and testing is being moved closer to the patient through rapid diagnostic technologies, including point-of-care (POC) technologies.

Advanced microbiology technologies are rapidly changing our ability to diagnose infections, improve patient care, and enhance clinical workflow. These tools are increasing the breadth, depth, and speed of diagnostic data generated per patient, and testing is being moved closer to the patient through rapid diagnostic technologies, including point-of-care (POC) technologies. While select stakeholders have an appreciation of the value/importance of improvements in the microbial diagnostic field, there remains a disconnect between clinicians and some payers and hospital administrators in terms of understanding the potential clinical utility of these novel technologies. Therefore, a key challenge for the clinical microbiology community is to clearly articulate the value proposition of these technologies to encourage payers to cover and hospitals to adopt advanced microbiology tests. Specific guidance on how to define and demonstrate clinical utility would be valuable. Addressing this challenge will require alignment on this topic, not just by microbiologists but also by primary care and emergency room (ER) physicians, infectious disease specialists, pharmacists, hospital administrators, and government entities with an interest in public health. In this article, we discuss how to best conduct clinical studies to demonstrate and communicate clinical utility to payers and to set reasonable expectations for what diagnostic manufacturers should be required to demonstrate to support reimbursement from commercial payers and utilization by hospital systems.

Assessment of rapid direct E-test on positive blood culture for same-day antimicrobial susceptibility

INTRODUCTION

Early and appropriated antimicrobial therapy showed to positively impact on the clinical improvement of septic patients. The aim of this study was to evaluate E-test methodology to obtain rapid results of antimicrobial susceptibility, starting directly from blood culture bottles positive to Gram-negative monomicrobial flora.

MATERIALS AND METHODS

One hundred and five blood culture samples positive to Gram-negative rods at the microscopic examination were collected. Bacterial identification from early subculture on blood agar after 4 h incubation and rapid direct E-test from blood culture broth were performed on every sample. Antibiotics MIC were achieved after 5-6 h of incubation. Resulting MIC values were compared with those obtained with reference E-test from the overnight subculture. Categorical agreement (CA) and essential agreement (EA) were evaluated.

RESULTS

Comparison between rapid direct E-test and reference E-test showed CA ranging from 95.1 to 100 % and 88.2 to 100 % for Enterobacteriaceae (EB) and for non-fermenting Gram-negative bacilli, respectively. Rapid direct E-test showed an overall EA of 80.1 %, revealing different EA rates for the tested antibiotics. Among carbapenemase-producing EB, CA of 87.5 % and EA of 75.5 % for MP were achieved.

DISCUSSION

The same-day communication of the antimicrobial susceptibility represents an important challenge in the multidrug-resistance era. Despite not being able to anticipate actual MIC values, the rapid direct E-test may be useful to obtain preliminary AST results in 5-6 h, especially if used in association with phenotypic or genotypic tests to identify the main resistance mechanisms.

Challenges and research priorities to progress the impact of antimicrobial stewardship

Antimicrobial stewardship programmes have been playing an important role in patient care and hospital policies. These programmes are now recognised as formal strategies for curbing the upward trend in antibiotic resistance and for improving the appropriate antimicrobial and antifungal use. The role of such programs in the era of antimicrobial resistance presents several unique challenges and opportunities, most notably in the diagnostic and therapeutic setting. Controversies remain regarding the most effective interventions and the appropriate design to evaluate their impact. In this review, based on rounds of discussion, we explain the most important challenges faced by antibiotic stewardship and antifungal stewardship programmes. We also try to suggest areas for further research.

A nationwide survey on involvement of clinical microbiologists in antibiotic stewardship programmes in large French hospitals

Antibiotic stewardship programmes (ASP) are essential to tackle antibiotic resistance. Clinical microbiologists (CMs) play a key role in these programmes; however, few studies describe their actual involvement. Our objective was to explore CMs' involvement in French hospital ASP. In 2018, we conducted a survey among CMs working in large public French hospitals (600 acute care beds or more). The questionnaire focused on the following topics: microbiology department's characteristics, hospital ASP, and CMs' involvement in this programme, including their use of rapid diagnostic tests (RDT). Fifty/74 CMs answered (response rate 68%), with 68% working in a teaching hospital. CMs were leading the ASP in 6% of cases, and 57% of hospitals had a multidisciplinary antibiotic stewardship team. Most microbiology departments (92%) were using specific PCR, processed 24/7 in 74% of hospitals. More than half (58%) were using syndromic panel-based testing, 94% mass spectrometry, and 96% immunochromatographic/colorimetric RDT. Blood cultures were processed 24/7 in 44% of hospitals. CMs were involved in this. Finally, 42% of CMs wished to be more involved in their hospital's ASP, the most frequently reported barrier being lack of time (36%). CMs should be more involved in ASP. RDT are widely used, but not implemented in an optimal way.

Accelerating Initiation of Adequate Antimicrobial Therapy Using Real-Time Decision Support and Microarray Testing

Introduction:

Bloodstream infections (BSI) represent a common cause of sepsis and mortality in children. Early and adequate empirical antimicrobial therapy is a critical component of successful treatment of BSI. Rapid PCR-based diagnostic technologies, such as nucleic acid microarrays, can decrease the time needed to identify pathogens and antimicrobial resistance and have the potential to ensure patients are started on adequate antibiotics as early as possible. However, without appropriate processes to support timely and targeted interpretation of these results, these advantages may not be realized in practice.

Methods:

Our Antimicrobial Stewardship Program (ASP) implemented a quality improvement initiative using the Institute for Healthcare Improvement’s Model for Improvement to decrease the time between a nucleic acid microarray result for Gram-positive bacteremia and the time a patient was placed on adequate antimicrobial therapy. The primary effective intervention was a near real-time notification system to the managing physicians of inadequate antimicrobial therapy via a call from the ASP team.

Results:

Following the intervention, the average time to adequate antimicrobial therapy in patients with Gram-positive BSI and inadequate coverage decreased from 38 hours with the nucleic acid microarray result alone to 4.7 hours when results were combined with an ASP clinical decision support intervention, an 87% reduction.

Conclusions:

The positive effects of rapid-detection technologies to improve patient care are enhanced when combined with clinical decision support tools that can target inadequate antimicrobial treatments in near real time.

Centralized Communication of Blood Culture Results Leveraging Antimicrobial Stewardship and Rapid Diagnostics

Objective

This study aimed to determine if integrating antimicrobial stewardship program (ASP) personnel with rapid diagnostic testing resulted in improved outcomes for patients with positive blood cultures.

Method

Beginning in 2016, Saint Luke’s Health System (SLHS) implemented a new process where all positive blood cultures were communicated to ASP personnel or SLHS pharmacy staff. Pharmacists then became responsible for interpreting results, assessing patient specific information, and subsequently relaying culture and treatment information to providers. This was a multisite, pre-post, quasi-experimental study (Pre: August to December 2014; Post: August to December 2016). Patients 18 years of age and older with a positive blood culture during admission were included (2014, n = 218; 2016, n = 286). Coprimary outcomes of time to optimal and appropriate therapy were determined from time of culture positivity via gram stain. Secondary outcomes focused on clinical, process, and fiscal endpoints. A pre-post intervention physician survey was conducted to assess the impact on antimicrobial decision making and perceived effect on patient outcomes.

Results

There was no difference in time to appropriate therapy groups (P = .079). Time to optimal therapy was 9.2 hours shorter in 2016 (P = .004). Provider surveys indicated the process improved communication among clinicians and facilitated a shared decision-making process with a perceived improvement in patient care.

Conclusions

An ASP-led blood culture communication process for patients with positive blood cultures was shown to improve time to optimal therapy, support physicians in their decision making on critical lab data, and improve the care for hospitalized patients.

Diagnosing and Managing Sepsis by Probing the Host Response to Infection: Advances, Opportunities, and Challenges

Sepsis is a major source of mortality and morbidity globally. Accurately diagnosing sepsis remains challenging due to the heterogeneous nature of the disease, and delays in diagnosis and intervention contribute to high mortality rates. Measuring the host response to infection enables more rapid diagnosis of sepsis than is possible through direct detection of the causative pathogen, and recent advances in host response diagnostics and prognostics hold promise for improving outcomes. The current review discusses recent advances in the technologies used to probe the host response to infection, particularly those based on transcriptomics. These are discussed in the context of contemporary approaches to diagnosing and prognosing sepsis, and recommendations are made for successful development and validation of host response technologies.

Hospital-onset adult invasive pneumococcal disease in Israel: Sicker patients, different pathogens

OBJECTIVES

Invasive pneumococcal disease (IPD) usually has its onset in the community (CO-IPD), but it can commence following hospitalization (HO-IPD). This study compared HO-IPD and CO-IPD cases during the implementation of the pneumococcal conjugate vaccine (PCV) program for children in Israel.

METHODS

This was a nationwide retrospective cohort study of adult (age >18 years) IPD patients covering the period from the implementation of the PCV7/13 program in 2009/2010 through 2015. HO-IPD and CO-IPD were defined as IPD with onset ≥4 and ≤2 days from admission, respectively. Patient characteristics, outcome measures, serotypes, and antimicrobial susceptibility were compared for the entire cohort, followed by a matched case-control analysis.

RESULTS

The study included 114 patients with HO-IPD and 2180 with CO-IPD. After matching HO-IPD to CO-IPD patients by age, sex, and comorbidities, the mortality rate and discharge to long-term care facility rate were significantly higher for HO-IPD patients than for CO-IPD patients (44.6% vs. 26.3% and 26.5% vs. 8.2%, respectively). HO-IPD isolates were less often covered by PCV13 (39.6% vs. 49.0%) and pneumococcal polysaccharide vaccine PPSV23 (56.6% vs. 71.3%) and more often resistant to penicillin (9.3% vs. 3.6%), ceftriaxone (3.8% vs. 0.75%), and levofloxacin (9.3% vs. 0.8%).

CONCLUSIONS

HO-IPD was associated with higher morbidity and mortality than CO-IPD and was more often caused by non-vaccine serotypes (primarily non-PCV13 types) and antibiotic-resistant strains.

Selective antibiotic susceptibility reporting and broad-spectrum intravenous antibiotic use: A multicentre ecological study

Recent estimates of inpatient antibiotic use in the USA suggest that broad-spectrum antibiotic use has increased significantly. The objective of this study was to assess the impact of a selective antibiotic susceptibility reporting intervention on broad-spectrum intravenous (i.v.) antibiotic use in seven hospitals of a health system in New Jersey. This was a retrospective pre- and post-intervention ecological study. Standardised selective antibiotic susceptibility reporting rules were developed and implemented between January 2016 and June 2017. The 8 months before and after each individual hospital's implementation constituted the pre- and post-intervention study periods. The primary outcome was the rate of broad-spectrum i.v. antibiotic use for hospital-onset/multidrug-resistant infections (broad MDR). Secondary outcome measures were the use rates of non-glycopeptide anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) agents, carbapenems, non-carbapenem antipseudomonal β-lactams, third-generation cephalosporins, first/second-generation cephalosporins, fluoroquinolones and narrow-spectrum penicillins. Antibiotic use data were collected as inpatient i.v. antibiotic days of therapy per 1000 patient days (DOT/1000-PD). Interrupted time series analysis with segmented regression was used to compare outcomes. There was no significant change in the use of broad MDR agents (slope change, +0.54 DOT/1000-PD per month, 95% confidence interval -1.78 to 2.87) or other antibiotic classes. Whilst the implementation of selective antibiotic susceptibility reporting across seven hospitals had no impact on overall broad-spectrum i.v. antibiotic use, further study is needed to determine the long-term impact of this intervention.

Rapid Susceptibility Testing Methods

With emerging antimicrobial resistance, rapid antimicrobial susceptibility testing (AST) is needed to provide early definitive therapeutic guidance to optimize patient outcome. Genotypic methods are fast, but can identify only a subset of known resistance elements. Phenotypic methods determine clinically predictive minimal inhibitory concentrations and include very sensitive optical and biophysical methods to detect changes in replication or physiology of pathogens in response to antibiotics. For the potential of rapid AST to be fully realized, results must be linked with robust decision support solutions that will implement therapeutic changes in real time.

Precision Pharmacotherapy: Integrating Pharmacogenomics into Clinical Pharmacy Practice

Precision pharmacotherapy encompasses the use of therapeutic drug monitoring; evaluation of liver and renal function, genomics, and environmental and lifestyle exposures; and analysis of other unique patient or disease characteristics to guide drug selection and dosing. This paper articulates real-world clinical applications of precision pharmacotherapy, focusing exclusively on the emerging field of clinical pharmacogenomics. This field is evolving rapidly, and clinical pharmacists now play an invaluable role in the clinical implementation, education, and research applications of pharmacogenomics. This paper provides an overview of the evolution of pharmacogenomics in clinical pharmacy practice, together with recommendations on how the American College of Clinical Pharmacy (ACCP) can support the advancement of clinical pharmacogenomics implementation, education, and research. Commonalities among successful clinical pharmacogenomics implementation and education programs are identified, with recommendations for how ACCP can leverage and advance these common themes. Opportunities are also provided to support the research needed to move the practice and application of pharmacogenomics forward.

Effect of antimicrobial stewardship with rapid MALDI-TOF identification and Vitek 2 antimicrobial susceptibility testing on hospitalization outcome

We sought to evaluate time for bacterial culture and initiation of appropriate therapy for patients, from 2017 (without rapid diagnostic test (RDT) and Antimicrobial Stewardship Program (ASP)) and 2018 (with RDT and ASP). Time to identification (ID) was significantly faster in 2018 (2018 24.9 ± 14.4, 2017 33.8 ± 17 h, P = 0.001). Time to antimicrobial susceptibility test (AST) results was significantly faster for patients in 2018 compared to 2017 (18.2 ± 14 h compared to 28.5 ± 14.9 h, P < 0.001). Length of hospital stay for enrolled patients was significantly shorter in 2018 compared to 2017 (2018 10.7 ± 11.1 days and 2017 15.5 ± 18.1 days, P = 0.05). Length of antimicrobial therapy for enrolled patients was significantly shorter for 2018 (2018 6.7 ± 3.8 d vs. 2017 8.8 ± 7.8 d, P = 0.036). These results demonstrate MALDI-TOF/Vitek 2 leads to an average 21.5 h faster ID and AST results that can be acted upon by ASP for antimicrobial recommendations.

Approche syndromique multiplexe en réanimation

Le développement récent des nouveaux tests de diagnostic rapide par PCR multiplexe à visée syndromique, capables de détecter plusieurs dizaines de pathogènes en quelques heures, a entraîné un changement de paradigme en microbiologie et en pratique clinique. Plusieurs d’entre eux, comme les panels pour détecter les germes en cause dans les bactériémies, les infections respiratoires hautes ou basses et les méningoencéphalites, sont déjà disponibles et peuvent apporter une aide dans le diagnostic des infections chez les patients de réanimation. Bien que ces nouvelles techniques présentent des avantages évidents pour le dénombrement de micro-organismes et parfois pour la détection simultanée de gènes de résistance, pour les délais d’exécution et de rendus de résultats, elles présentent cependant certains défis, comme l’évaluation de leurs performances réelles, leur coût très élevé, le choix des stratégies d’utilisation et l’interprétation clinicobiologique des résultats. Dans cet article, nous avons passé en revue les différents tests qui peuvent ou pourront aider les réanimateurs dans leur pratique quotidienne, relevé leurs limites et leur impact bénéfique potentiel sur le soin des patients.

Comparing Patient Risk Factor-, Sequence Type-, and Resistance Locus Identification-Based Approaches for Predicting Antibiotic Resistance in Escherichia coli Bloodstream Infections

Rapid diagnostic tests for antibiotic resistance that identify the presence or absence of antibiotic resistance genes/loci are increasingly being developed. However, these approaches usually neglect other sources of predictive information which could be identified over shorter time periods, including patient epidemiologic risk factors for antibiotic resistance and markers of lineage. Using a data set of 414 Escherichia coli isolates recovered from separate episodes of bacteremia at a single academic institution in Toronto, Ontario, Canada, between 2010 and 2015, we compared the potential predictive ability of three approaches (epidemiologic risk factor-, pathogen sequence type [ST]-, and resistance gene identification-based approaches) for classifying phenotypic resistance to three antibiotics representing classes of broad-spectrum antimicrobial therapy (ceftriaxone [a 3rd-generation cephalosporin], ciprofloxacin [a fluoroquinolone], and gentamicin [an aminoglycoside]). We used logistic regression models to generate model receiver operating characteristic (ROC) curves. Predictive discrimination was measured using apparent and corrected (bootstrapped) areas under the curves (AUCs). Epidemiologic risk factor-based models based on two simple risk factors (prior antibiotic exposure and recent prior susceptibility of Gram-negative bacteria) provided a modest predictive discrimination, with AUCs ranging from 0.65 to 0.74. Sequence type-based models demonstrated strong discrimination (AUCs, 0.83 to 0.94) across all three antibiotic classes. The addition of epidemiologic risk factors to sequence type significantly improved the ability to predict resistance for all antibiotics (P < 0.05). Resistance gene identification-based approaches provided the highest degree of discrimination (AUCs, 0.88 to 0.99), with no statistically significant benefit being achieved by adding the patient epidemiologic predictors. In summary, sequence type or other lineage-based approaches could produce an excellent discrimination of antibiotic resistance and may be improved by incorporating readily available patient epidemiologic predictors but are less discriminatory than identification of the presence of known resistance loci.

Evaluation of rapid polymerase chain reaction-based organism identification of gram-positive cocci for patients with a single positive blood culture

For patients with a single-positive blood culture growing gram-positive cocci, organism identification can provide supportive information for differentiating contamination from infection. We investigated the effect of a rapid blood culture identification panel (BCID) on vancomycin-prescribing patterns and patient outcomes for single positive blood culture (PBC) growing gram-positive cocci. Adult patients with single-positive blood culture growing gram-positive cocci with conventional organism identification (pre-BCID) were compared with organism identification by BCID (post-BCID). Antimicrobial Stewardship Program (ASP) review of PBC was performed in both study groups. Vancomycin prescribing patterns were studied. Secondary endpoints were the incidence of nephrotoxicity, length of stay (LOS), readmission rate, mortality, and hospital costs. A total of 188 patients (86 pre-BCID, 102 post-BCID) were included. Organism identification was known 21 h sooner in the post-BCID group (P < 0.001). Coagulase-negative staphylococci were the most commonly isolated organisms (73%). In patients where vancomycin was deemed unnecessary (n = 133), vancomycin use (51% pre-BCID vs 36% post-BCID; P = 0.09) and time from culture positivity to vancomycin discontinuation (1.5 vs. 1.7 days; P = 0.92) did not differ between groups. We found no differences in the development of nephrotoxicity, LOS, readmission, mortality, or hospital costs. Earlier identification of single positive blood culture growing gram-positive cocci did not significantly influence prescribing patterns of vancomycin. However, baseline antimicrobial stewardship review of single positive blood culture growing gram-positive cocci may have lessened the opportunity for detectable differences. Larger studies, accounting for the impact of ASP intervention, should be performed to determine the value of each individual component.

Antibiotic stewardship in the intensive care unit: Challenges and opportunities

Infections due to antibiotic-resistant organisms are increasing in prevalence and represent a major public health threat. Antibiotic overuse is a major driver of this epidemic, and antibiotic stewardship an important means of limiting antibiotic resistance. The intensive care unit (ICU) setting presents an intersection of opportunities and challenges for effective antibiotic stewardship, but limited data inform optimal stewardship interventions in this setting. In this review, we present unique considerations for stewardship interventions the ICU setting and summarize available data evaluating the impact of prospective audit and feedback, diagnostic test stewardship, rapid molecular diagnostic tests, and procalcitonin-guided algorithms for antibiotic discontinuation. The existing knowledge gaps ripe for future research are emphasized.

A Systematic Review and Meta-analysis of Antibiotic Treatment Duration for Bacteremia Due to Enterobacteriaceae

The duration of antibiotic therapy for bacteremia due to Enterobacteriaceae is not well defined. We sought to evaluate the clinical outcomes with shorter- versus longer-course treatment. We performed a systematic search of the PubMed and EMBASE databases through May 2018. Studies presenting comparative outcomes between patients receiving antibiotic treatment for ≤10 days ("short-course") and those treated for >10 days ("long-course") were considered eligible. Four retrospective cohort studies and one randomized controlled trial comprising 2,865 patients met the inclusion criteria. The short- and long-course antibiotic treatments did not differ in 30-day all-cause mortality (1,374 patients; risk ratio [RR] = 0.99; 95% confidence interval [CI], 0.69 to 1.43), 90-day all-cause mortality (1,750 patients; RR = 1.16; 95% CI, 0.81 to 1.66), clinical cure (1,080 patients; RR = 1.02; 95% CI, 0.96 to 1.08), or relapse at 90 days (1,750 patients; RR = 1.08; 95% CI, 0.69 to 1.67). In patients with bacteremia due to Enterobacteriaceae, the short- and long-course antibiotic treatments did not differ significantly in terms of clinical outcomes. Further well-designed studies are needed before treatment for 10 days or less is adopted in clinical practice.

Detection of vancomycin-resistant Enterococcus faecium hospital-adapted lineages in municipal wastewater treatment plants indicates widespread distribution and release into the environment

Vancomycin-resistant Enterococcus faecium (VREfm) is a leading cause of healthcare-associated infection. Reservoirs of VREfm are largely assumed to be nosocomial although there is a paucity of data on alternative sources. Here, we describe an integrated epidemiological and genomic analysis of E. faecium associated with bloodstream infection and isolated from wastewater. Treated and untreated wastewater from 20 municipal treatment plants in the East of England, United Kingdom was obtained and cultured to isolate E. faecium, ampicillin-resistant E. faecium (AREfm), and VREfm. VREfm was isolated from all 20 treatment plants and was released into the environment by 17/20 plants, the exceptions using terminal ultraviolet light disinfection. Median log₁₀ counts of AREfm and VREfm in untreated wastewater from 10 plants in direct receipt of hospital sewage were significantly higher than 10 plants that were not. We sequenced and compared the genomes of 423 isolates from wastewater with 187 isolates associated with bloodstream infection at five hospitals in the East of England. Among 481 E. faecium isolates belonging to the hospital-adapted clade, we observed genetic intermixing between wastewater and bloodstream infection, with highly related isolates shared between a major teaching hospital in the East of England and 9/20 plants. We detected 28 antibiotic resistance genes in the hospital-adapted clade, of which 23 were represented in bloodstream, hospital sewage, and municipal wastewater isolates. We conclude that our findings are consistent with widespread distribution of hospital-adapted VREfm beyond acute healthcare settings with extensive release of VREfm into the environment in the East of England.

The Hypothetical Impact of Accelerate Pheno on Time to Effective Therapy and Time to Definitive Therapy for Bloodstream Infections Due to Drug-Resistant Gram-Negative Bacilli

Strategies are needed to improve time to optimal therapy in patients with bloodstream infections (BSI) due to resistant Gram-negative (GN) pathogens. Accelerate Pheno (ACC) can provide antimicrobial susceptibility results within 7 h of a positive culture and may more rapidly optimize therapy. The primary objective of this study was to evaluate the hypothetical impact of ACC on time to effective therapy (TTET) and time to definitive therapy (TTDT) among patients with BSI due to resistant GN pathogens. ACC was performed on resistant GN BSI isolates, and results were not available to clinicians in real time. A potential benefit of having ACC on TTET or TTDT was determined if modifications to antimicrobial regimens could have been made sooner with ACC. Comparisons on the impact of ACC in the presence or absence of testing by the Verigene Gram-negative blood culture test (Verigene GN-BC) were performed. Sixty-one patients with resistant GN BSI were evaluated. The median actual TTET and TTDT in the cohort were 25.9 h (interquartile range [IQR], 18.5, 42.1) and 47.6 h (IQR, 24.9, 79.6), respectively. Almost half of the patients had potential improvement in TTET and/or TTDT with ACC. In patients who would have had a benefit the median potential decreases in TTET and TTDT were 16.6 h (IQR, 5.5 to 30.6) and 29.8 h (IQR, 13.6 to 43), respectively. The largest potential improvements were seen in patients for whom Verigene results were not available. In conclusion, among patients with resistant GN BSI in a setting where other rapid diagnostic technologies are utilized, ACC results could have further improved TTET and TTDT.

Advancing Infectious Diseases Diagnostic Testing and Applications to Antimicrobial Therapy in the ICU

Treatment of suspected infections in critically ill patients requires the timely initiation of appropriate antimicrobials and rapid de-escalation of unnecessary broad-spectrum coverage. New advances in rapid diagnostic tests can now offer earlier detection of pathogen and potential resistance mechanisms within hours of initial culture growth. These technologies, combined with pharmacist antimicrobial stewardship efforts, may result in shorten time to adequate coverage or earlier de-escalation of unnecessary broad spectrum antimicrobials, which could improve patient outcomes and lower overall treatment cost. Furthermore, de-escalation of antimicrobials may lead to decreased emergence of resistant organisms and adverse events associated with antimicrobials. Clinical pharmacists should be aware of new rapid diagnostic tests, including their application, clinical evidence, and limitations, in order to implement the most appropriate clinical treatment strategy when patients have positive cultures. This review will focus on commercially available rapid diagnostic tests for infections that are routinely encountered by critically ill patients, including gram-positive and gram-negative bacterial blood stream infections, Candida, and Clostridioides difficile.

Ceftobiprole activity when tested against contemporary bacteria causing bloodstream infections in the United States (2016-2017)

Ceftobiprole medocaril, the prodrug of ceftobiprole, is an advanced-generation cephalosporin that is approved in many European and non-European countries for the treatment of adults with hospital-acquired pneumonia (excluding ventilator-associated pneumonia) and community-acquired pneumonia and is currently being evaluated in a global phase 3 clinical trial of patients with Staphylococcus aureus bacteremia. This study investigated the in vitro activity of ceftobiprole and comparators against a total of 5466 gram-positive and -negative isolates from bloodstream infections (BSIs) that were collected in the United States during 2016 and 2017 as part of the SENTRY Antimicrobial Surveillance Program. Ceftobiprole was highly active (isolates were >99% susceptible) against S. aureus (including methicillin-resistant S. aureus), coagulase-negative staphylococci, Enterococcus faecalis, streptococci, and non-extended-spectrum β-lactamase (non-ESBL) phenotype Enterobacteriaceae. As expected, lower activities were observed against Enterococcus faecium, ESBL-phenotype Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii. These results support further clinical evaluation of ceftobiprole for the treatment of BSIs caused by susceptible organisms.

Rationalizing antimicrobial therapy in the ICU: a narrative review

The massive consumption of antibiotics in the ICU is responsible for substantial ecological side effects that promote the dissemination of multidrug-resistant bacteria (MDRB) in this environment. Strikingly, up to half of ICU patients receiving empirical antibiotic therapy have no definitively confirmed infection, while de-escalation and shortened treatment duration are insufficiently considered in those with documented sepsis, highlighting the potential benefit of implementing antibiotic stewardship programs (ASP) and other quality improvement initiatives. The objective of this narrative review is to summarize the available evidence, emerging options, and unsolved controversies for the optimization of antibiotic therapy in the ICU. Published data notably support the need for better identification of patients at risk of MDRB infection, more accurate diagnostic tools enabling a rule-in/rule-out approach for bacterial sepsis, an individualized reasoning for the selection of single-drug or combination empirical regimen, the use of adequate dosing and administration schemes to ensure the attainment of pharmacokinetics/pharmacodynamics targets, concomitant source control when appropriate, and a systematic reappraisal of initial therapy in an attempt to minimize collateral damage on commensal ecosystems through de-escalation and treatment-shortening whenever conceivable. This narrative review also aims at compiling arguments for the elaboration of actionable ASP in the ICU, including improved patient outcomes and a reduction in antibiotic-related selection pressure that may help to control the dissemination of MDRB in this healthcare setting.

Rapid antimicrobial susceptibility testing by VITEK®2 directly from blood cultures in patients with Gram-negative rod bacteremia

OBJECTIVE

Optimizing therapy for bacteremia is currently limited by the 1-2-day turnaround time required for antimicrobial susceptibility testing (AST). Here, we assess a rapid AST method with VITEK®2 (bioMérieux, France) directly from positive blood cultures.

METHODS

Patient-derived positive blood cultures with Gram-negative rods identified as Enterobacteriaceae and Pseudomonas aeruginosa were prospectively tested, and other blood culture bottles were spiked with carbapenem-resistant Enterobacteriaceae (CRE). Positive cultures were subjected to red blood cell lysis and centrifugation, and setup on VITEK®2.

RESULTS

A total of 109 patient blood cultures and 52 spiked blood cultures were tested. Overall, essential agreement was 97.7% [95% confidence interval (CI) 96.4-99.0], and categorical agreement was 96.8% (95% CI 95.0-98.6). Mean turnaround time from setup to susceptibility results for Enterobacteriaceae in the clinical cultures was 9.0 (±1.3) h.

CONCLUSIONS

Direct susceptibility testing of blood cultures by VITEK®2 for Enterobacteriaceae is an accurate, practical, and inexpensive diagnostic strategy for rapid automated AST.

Predictors of Time to Effective and Optimal Antimicrobial Therapy in Patients With Positive Blood Cultures Identified via Molecular Rapid Diagnostic Testing

Antimicrobial stewardship (AMS) programs integrated with rapid diagnostic tests optimize patient outcomes and reduce time to effective therapy (TTET) and time to optimal therapy (TTOT). This study identifies predictors of TTET and TTOT among patients with positive blood cultures and identifies limitations to current TTOT definitions and outcomes.

Susceptibility Provision Enhances Effective De-escalation (SPEED): utilizing rapid phenotypic susceptibility testing in Gram-negative bloodstream infections and its potential clinical impact

Objectives

We evaluated the performance and time to result for pathogen identification (ID) and antimicrobial susceptibility testing (AST) of the Accelerate Pheno™ system (AXDX) compared with standard of care (SOC) methods. We also assessed the hypothetical improvement in antibiotic utilization if AXDX had been implemented.

Methods

Clinical samples from patients with monomicrobial Gram-negative bacteraemia were tested and compared between AXDX and the SOC methods of the VERIGENE® and Bruker MALDI Biotyper® systems for ID and the VITEK® 2 system for AST. Additionally, charts were reviewed to calculate theoretical times to antibiotic de-escalation, escalation and active and optimal therapy.

Results

ID mean time was 21 h for MALDI-TOF MS, 4.4 h for VERIGENE® and 3.7 h for AXDX. AST mean time was 35 h for VITEK® 2 and 9.0 h for AXDX. For ID, positive percentage agreement was 95.9% and negative percentage agreement was 99.9%. For AST, essential agreement was 94.5% and categorical agreement was 93.5%. If AXDX results had been available to inform patient care, 25% of patients could have been put on active therapy sooner, while 78% of patients who had therapy optimized during hospitalization could have had therapy optimized sooner. Additionally, AXDX could have reduced time to de-escalation (16 versus 31 h) and escalation (19 versus 31 h) compared with SOC.

Conclusions

By providing fast and reliable ID and AST results, AXDX has the potential to improve antimicrobial utilization and enhance antimicrobial stewardship.

Impact of infectious diseases consultation on the outcome of patients with bacteraemia

Bacteraemia or bloodstream infections (BSI) are associated with much morbidity and mortality. Management of patients with bacteraemia is complex, and the increase in immunosuppressed patients and multidrug-resistant organisms poses additional challenges. The objective of this review is to assess the available published information about the impact of different aspects of management on the outcome of patients with BSI, and, specifically, the importance of infectious diseases specialists (IDS) consultation. The impact of management by IDS on different aspects, including interpretation of newer rapid techniques, early evaluation and treatment, and follow up, are reviewed. Overall, the available data suggest that IDS intervention improves the management and outcome of patients with BSI, either through consultation or structured unsolicited interventions in the context of multidisciplinary bacteraemia programmes.

Comparison of Pharmacist-Directed Management of Multiplex PCR Blood Culture Results with Conventional Microbiology Methods on Effective and Optimal Therapy within a Community Hospital

Multiplex PCR combined with a pharmacist-driven reporting protocol was compared to the standard of care within a community hospital to evaluate initial changes after notification of a positive blood culture. The intervention group demonstrated decreased times to changes in antimicrobial therapy (P = 0.0081), increased changes to optimal antimicrobial therapy (P = 0.013), and decreased vancomycin use for coagulase-negative staphylococcus contaminants (P < 0.01) with multiplex PCR implementation and pharmacist intervention.

Validation of a novel molecular diagnostic panel for pediatric musculoskeletal infections: Integration of the Cepheid Xpert MRSA/SA SSTI and laboratory-developed real-time PCR assays for clindamycin resistance genes and Kingella kingae detection

BACKGROUND

Pathogen detection in pediatric patients with musculoskeletal infections relies on conventional bacterial culture, which is slow and can delay antimicrobial optimization. The ability to rapidly identify causative agents and antimicrobial resistance genes in these infections may improve clinical care.

METHODS

Convenience specimens from bone and joint samples submitted for culture to Children's Hospital Colorado (CHCO) from June 2012 to October 2016 were evaluated using a "Musculoskeletal Diagnostic Panel" (MDP) consisting of the Xpert MRSA/SA SSTI real-time PCR (qPCR, Cepheid) and laboratory-developed qPCRs for Kingella kingae detection and erm genes A, B, and C which confer clindamycin resistance. Results from the MDP were compared to culture and antimicrobial susceptibility testing (AST) results.

RESULTS

A total of 184 source specimens from 125 patients were tested. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the Xpert MRSA/SA SSTI compared to culture and AST results were 85%, 98%, 93%, and 95% respectively for MSSA and 82%, 100%, 100%, and 99% for MRSA. Compared to phenotypic clindamycin resistance in S. aureus isolates, the erm A, B, and C gene PCRs collectively demonstrated a sensitivity, specificity, PPV, and NPV of 80%, 96%, 67%, and 98%. In comparison to clinical truth, Kingella PCR had a sensitivity, specificity, PPV, and NPV of 100%, 99.5%, 100%, and 100%.

CONCLUSIONS

This novel MDP offers a rapid, sensitive, and specific option for pathogen detection in pediatric patients with musculoskeletal infections.

Laboratory Automation in Clinical Microbiology

Laboratory automation is currently the main organizational challenge for microbiologists. Automating classic workflows is a strenuous process for the laboratory personnel and a huge and long-lasting financial investment. The investments are rewarded through increases in quality and shortened time to report. However, the benefits for an individual laboratory can only be estimated after the implementation and depending on the classic workflows currently performed. The two main components of automation are hardware and workflow. This review focusses on the workflow aspects of automation and describes some of the main developments during recent years. Additionally, it tries to define some terms which are related to automation and specifies some developments which would further improve automated systems.

Impact of short-incubation MALDI-TOF MS on empiric antibiotic therapy in bloodstream infections caused by Pseudomonas aeruginosa, Enterococcus spp. and AmpC-producing Enterobacteriaceae

The impact of the short-incubation matrix-assisted laser desorption ionization time-of-flight (si-MALDI-TOF) mass spectrometry technique was evaluated in the treatment of bloodstream infections (BSIs) caused by Pseudomonas aeruginosa, Enterococcus spp., and Amp-C producing Enterobacteriaceae. A total of 124 bacteremia episodes were divided into 2 groups: i) si-MALDI-TOF group (n = 69) and ii) control group (n = 55). Identification by si-MALDI-TOF resulted in 12.8% increase in cases receiving appropriate antibiotic treatment within 48 h from blood culture draw. The importance of the rapid identification was emphasized in BSIs caused by enterococci (n = 62), where si-MALDI-TOF led to appropriate antibiotic treatment in 87.9% of cases (versus control group 65.5%, P = 0.036). Implementation of si-MALDI-TOF technology for microbial identification was associated with increased proportion of patients receiving effective antibiotic treatment within 48 h from blood culture draw. The effect was most significant in BSIs caused by enterococcal species and in a subgroup of immunosuppressed patients.

Comparison of the Fully Automated FilmArray BCID Assay to a 4-Hour Culture Test Coupled to Mass Spectrometry for Day 0 Identification of Microorganisms in Positive Blood Cultures

Rapid bacterial identification of positive blood culture is important for adapting the antimicrobial therapy in patients with blood stream infection. The aim of this study was to evaluate the performance of the multiplex FilmArray Blood Culture Identification (BCID) assay by comparison to an in-house protocol based on MALDI-TOF MS identification of microcolonies after a 4-hour culture, for identifying on the same day the microorganisms present in positive blood culture bottles. One hundred and fifty-three positive bottles from 123 patients were tested prospectively by the 3 techniques of bacterial identification: 11 bottles yielding negative results by the 3 tests were considered false positive (7.2%). The reference MALDI-TOF MS technique identified 134 monomicrobial (87.6%) and 8 double infections (5.2%), which resulted in a total of 150 microorganisms. Globally, 137 (91.3%) of these 150 pathogens were correctly identified by the fully automated multiplex FilmArray BCID system at the species or genus level on day of growth detection, versus 117 (78.8%) by MALDI-TOF MS identification on nascent microcolonies after a 4-hour culture (P < 0.01). By combining the two approaches, 140 (93.5%) of the positive bottles were identified successfully at day 0. These results confirm the excellent sensitivity of the FilmArray BCID assay, notably in case of multimicrobial infection. Due to the limited number of targets included into the test, it must be coupled to another identification strategy, as that presented in this study relying on MALDI-TOF MS identification of microcolonies obtained after a very short culture period.

Interplay between Rapid Diagnostic Tests and Antimicrobial Stewardship Programs among Patients with Bloodstream and Other Severe Infections

BACKGROUND

Antimicrobial stewardship programs (ASPs) aim to provide optimal antimicrobial therapy to patients quickly to improve the likelihood of overcoming infection while reducing the risk of adverse effects. Rapid diagnostic tests (RDTs) for infectious diseases have become an integral tool for ASPs to achieve these aims.

CONTENT

This review explored the demonstrated clinical value of longer-standing technologies and implications of newer RDTs from an antimicrobial stewardship perspective. Based on available literature, the focus was on the use of RDTs in bloodstream infections (BSIs), particularly those that perform organism identification and genotypic resistance detection, phenotypic susceptibility testing, and direct specimen testing. Clinical implications of rapid testing among respiratory, central nervous system, and gastrointestinal infections are also reviewed.

SUMMARY

Coupling RDTs with ASPs facilitates the appropriate and timely use of test results, translating into improved patient outcomes through optimization of antimicrobial use. These benefits are best demonstrated in the use of RDT in BSIs. Rapid phenotypic susceptibility testing offers the potential for early pharmacokinetic/pharmacodynamic optimization, and direct specimen testing on blood may allow ASPs to initiate appropriate therapy and/or tailor empiric therapy even sooner than other RDTs. RDTs for respiratory, central nervous system, and gastrointestinal illnesses have also shown significant promise, although more outcome studies are needed to evaluate their full impact.

Pathologic Difference between Sepsis and Bloodstream Infections

BACKGROUND

Sepsis, defined as life-threatening organ failure caused by a dysregulated host response to infection, is a major cause of morbidity and mortality in hospitalized patients. Understanding the features that distinguish sepsis from bloodstream infections (and other types of infection) can help clinicians appropriately and efficiently target their diagnostic workup and therapeutic interventions, especially early in the disease course.

CONTENT

In this review, sepsis and bloodstream infections are both defined, with a focus on recent changes in the sepsis definition. The molecular and cellular pathways involved in sepsis pathogenesis are described, including cytokines, the coagulation cascade, apoptosis, and mitochondrial dysfunction. Laboratory tests that have been evaluated for their utility in sepsis diagnosis are discussed.

SUMMARY

Sepsis is defined not only by the presence of an infection, but also by organ dysfunction from a dysregulated host response to that infection. Numerous pathways, including proinflammatory and antiinflammatory cytokines, the coagulation cascade, apoptosis, and mitochondrial dysfunction, help determine if a bloodstream infection (or any other infection) progresses to sepsis. Many biomarkers, including C-reactive protein, procalcitonin, and lactic acid have been evaluated for use in sepsis diagnosis, although none are routinely recommended for that purpose in current clinical practice. While some laboratory tests can help distinguish the 2, the presence of organ dysfunction is what separates sepsis from routine infections.

Cost of managing meningitis and encephalitis among infants and children in the United States

A retrospective cohort study design was used to assess the use and costs of diagnostic tests, medication, and total hospitalization costs for pediatric patients with suspected meningitis/encephalitis who received a lumbar puncture (LP) procedure. Related costs were calculated by timing of LP performed and infectious etiology for infants (<1 year) and children (1-17 years). A total of 3030 infants and 3635 children with suspected ME diagnosed between 2011 and 2014 were included in the study. The mean hospitalization cost for infants and children was $12,759 and $11,119, respectively, with medication and laboratory test costs of $834 and $1771 for infants and $825 and $855 for children, respectively. Total visit cost increased with delayed LP procedure, ICU stay, and if the etiology was viral (other than enterovirus or arbovirus) or bacterial. Higher diagnostic and treatment costs were associated with delayed LP procedure, etiologic agent, and ICU stay.

Impact of a Multiplex PCR Assay for Bloodstream Infections With and Without Antimicrobial Stewardship Intervention at a Cancer Hospital

Implementation of Biofire FilmArray Blood Culture Identification Multiplex PCR panel (BCID) at a cancer hospital was associated with reduced time to appropriate antimicrobial therapy. Additional reductions were not observed when BCID was coupled with antimicrobial stewardship intervention.

Validation of an Antimicrobial Stewardship-Driven Verigene Blood-Culture Gram-Negative Treatment Algorithm to Improve Appropriateness of Antibiotics

Rapid diagnostic testing (RDT) allows for early adjustment of antibiotic therapy. This study examined the potential impact of a stewardship-driven antibiotic treatment algorithm, incorporating RDT into the management of Gram-negative bacteremia. The proposed algorithm would have resulted in 88.4% of cases receiving appropriate antibiotic therapy versus 78.1% by standard of care (P = .014).

Current and Future Opportunities for Rapid Diagnostics in Antimicrobial Stewardship

Rapid diagnostic testing has improved clinical care of patients with infectious syndromes when combined with antimicrobial stewardship. The authors review the current data on antimicrobial stewardship and rapid diagnostic testing in bloodstream, respiratory tract, and gastrointestinal tract infections. Evidence for the potential benefit of rapid tests in bloodstream infections seems strong, respiratory tract infections mixed, and gastrointestinal tract infections still evolving. The authors also review future directions in rapid diagnostic testing and suggest areas of focus for antimicrobial stewardship efforts.

Rapid diagnostics for bloodstream infections: A primer for infection preventionists

Accurate and rapid antimicrobial susceptibility testing with pathogen identification in bloodstream infections is critical to life results for early sepsis intervention. Advancements in rapid diagnostics have shortened the time to results from days to hours and have had positive effects on clinical outcomes and on efforts to combat antimicrobial resistance when paired with robust antimicrobial stewardship programs. This article provides infection preventionists with a working knowledge of available rapid diagnostics for bloodstream infections.

Management and outcome of bloodstream infections: a prospective survey in 121 French hospitals (SPA-BACT survey)

Background

Bloodstream infections (BSIs) are severe infections that can be community or hospital acquired. Effects of time to appropriate treatment and impact of antimicrobial management team are discussed in terms of outcome of BSI. We sought to evaluate the impact of initial BSI management on short-term mortality.

Patients and methods

A prospective, multicenter survey was conducted in 121 French hospitals. Participants declaring BSI during a 1-month period were included consecutively. Data on patient comorbidities, illness severity, BSI management, and resistance profile of bacterial strains were collected. Predictors of 10-day mortality were identified by multivariate regression for overall BSI, health care-related and hospital-acquired BSI.

Results

We included 1,952 BSIs. More than a third of them were hospital acquired (39%). Multidrug resistance was identified in 10% of cases, mainly in health care-related BSI. Empirical therapy and targeted therapy were appropriate for 61% and 94% of cases, respectively. Increased 10-day mortality was associated with severe sepsis, septic shock, increasing age, and any focus other than the urinary tract. Decreased mortality was associated with receiving at least one active antibiotic within the first 48 hours. Intervention of antimicrobial management team during the acute phase of BSI was associated with a decreased mortality at day 10 in the overall population and in health care-related BSI.

Conclusion

Optimizing BSI management by increasing rapidity of appropriate treatment initiation may decrease short-term mortality, even in countries with low rate of multidrug-resistant organisms. Early intervention of antimicrobial management team is crucial in terms of mortality.

Unsolicited consultation by infectious diseases specialist improves outcomes in patients with bloodstream infection: A prospective cohort study

INTRODUCTION

The objective of this study was to evaluate the impact of an intervention based on unsolicited consultations by an infectious diseases specialist (IDS) on the adequacy of antimicrobial treatment and mortality in patients with BSI.

METHODS

A prospective cohort study was performed in a 410-bed hospital. An intervention based on unsolicited consultation by an IDS for patients with BSI was performed only on days when an IDS was available. Outcomes were the percentage of days on optimal antimicrobial treatment (PDOAT) and mortality. Analyses were performed by linear regression and multivariate logistic regression.

RESULTS

Of 400 episodes of BSI included, 292 received the intervention. The median (interquartile range) PDOAT among those with and without the intervention was 93 (6-100) and 0 (0-53), respectively. The intervention was independently associated with a higher PDOAT (r = 0.5; p < 0.001) but not with mortality. The IDS recommendations were followed in full in 183 episodes, and not in 109. Mortality was 10.4% and 27.6%, respectively. Adherence to recommendations was associated with lower mortality (adjusted OR = 0.3; 95% CI: 0.1-0.5).

CONCLUSIONS

An intervention based on unsolicited IDS consultation for BSI episodes was associated with improved use of antibiotics and, when the recommendations were fully followed, with lower mortality.