Integrating rapid diagnostics and antimicrobial stewardship improves outcomes in patients with antibiotic-resistant Gram-negative bacteremia

Day at the Races: Comparing BioFire FilmArray Blood Culture ID Panels to Verigene Blood Culture in Gram-negative Bloodstream Infections using DOOR-MAT Analysis

Three rapid diagnostic test panels (Verigene BC-GN, BioFire BCID, and BCID 2 [RUO]) were compared using the Desirability of Outcome Ranking Management of Antimicrobial Therapy (DOOR-MAT) to evaluate potential downstream antimicrobial prescribing decisions resulting from the panels’ different organism and resistance detection. BioFire BCID 2 (RUO) had the best mean DOOR-MAT scores.

Physician Responsiveness to Positive Blood Culture Results at the Minneapolis Veterans Affairs Hospital-Is Anyone Paying Attention?

Background

Patients presenting with suspected infections are typically placed on empiric broad-spectrum antibiotics. With mounting evidence supporting the efficacy of using the narrowest spectrum of antimicrobial therapy to cover the suspected pathogen, current guidelines recommend decreasing the breadth of coverage in response to culture results both in relation to microbe identification and antibiotic sensitivity.

Methods

A retrospective chart review of electronic health records at the Minneapolis Veterans Affairs Medical Center (VAMC) in Minnesota was performed for 208 positive blood cultures with antibiotic spectrum analysis from July 1, 2015 to June 30, 2016. The time of reporting for pathogen identification and subsequent pathogen susceptibilities were compared to the time at which any alterations to antibiotic coverage were made. The breadth of antibiotic coverage was recorded using a nonlinear spectrum score. The use of this score allowed for the reliable classification of antibiotic adjustments as either deescalation, escalation, or no change.

Results

The percentage of cases deescalated was higher in response to physician (house staff or attending physician) notification of pathogen susceptibility information when compared with a response to pathogen identification alone (33.2% vs 22.6%). Empiric antibiotics were not altered within 24 hours in response to pathogen identification in 70.7% of cases and were not altered within 24 hours in response to pathogen sensitivity determination in 58.6% of cases. However, when considering the time frame from when empiric antibiotics were started to 24 hours after notification of susceptibility information, 49.5% of cases were deescalated and 41.5% of cases had no net change in the antibiotic spectrum score. The magnitude of deescalations were notably larger than escalations. The mean (SD) time to deescalation of antibiotic coverage was shorter (P =.049) in response to pathogen identification at 8 (7.4) hours compared with sensitivity information at 10.4 (7) hours, but may not be clinically relevant.

Conclusion

Health care providers at the Minneapolis VAMC appear to be using positive blood culture results in a timely fashion consistent with best practices. Because empirically initiated antibiotics typically are broad in spectrum, the magnitude of deescalations were notably larger than escalations. Adherence to these standards may be a reflection of the infectious disease staff oversight of antibiotic administration. Furthermore, the systems outlined in this quality improvement study may be replicated at other VAMCs across the country by either in-house infectious disease staff or through remote monitoring of the electronic health record by other infectious disease experts at a more centralized VAMC. Widespread adoption throughout the Veterans Health Administration may result in improved antibiotic resistance profiles and better clinical outcomes for our nation's veterans.

Quality of care indicators in the MAnageMent of BlOOdstream infections caused by Enterobacteriaceae (MAMBOO-E study): state of the art and research agenda

OBJECTIVES

The impact on outcome of five interventions was reviewed in order to investigate the state of the art for management of Enterobacteriaceae bloodstream infection (E-BSI).

METHODS

We searched for randomised controlled trials (RCTs) and observational studies published from January 2008 to March 2019 in PubMed, EMBASE and Cochrane Library. Populations consisted of patients with E-BSI. Interventions were as follows: (i) performance of imaging to assess BSI source and/or complications; (ii) follow-up blood cultures (FU-BCs); (iii) use of loading dose followed by extended/continuous infusion (E/CI) of β-lactams; (iv) duration of treatment (short- versus long-term); and (v) infectious diseases (ID) consultation. Patients without intervention were considered as controls. The main outcome was 30-day mortality. RoB 2.0 and ROBINS-I tools were used for bias assessment.

RESULTS

No study was eligible for interventions i, iii and v. For FU-BCs, one observational study including 901 patients with E-BSI was considered. Intervention consisted of repeating BCs within 2-7 days after index BCs. All-cause 30-day mortality was 14.2% (35/247) in the intervention group versus 14.7% (96/654) in the control group. For short treatment duration, two RCTs and six observational studies were included comprising 4473 patients with E-BSI. All-cause mortality was similar in the short and long treatment groups (OR = 1.10, 95% CI 0.83-1.44).

CONCLUSION

Of the assessed interventions, only short treatment duration in non-immunocompromised patients with E-BSI is supported by current data. Studies investigating the use of systematic imaging, FU-BCs, E/CI β-lactams and ID consultation in patients with E-BSI are needed.

Role of Rapid Diagnostics in Diagnosis and Management of Patients With Sepsis

Delayed administration of active anti-infective therapy is associated with increased rates of adverse events, mortality, and costs among sepsis patients. Inherent limitations of conventional culture identification methods and the lengthy turnaround time of antimicrobial susceptibility testing are significant barriers to the timely delivery of life-saving therapy, particularly among antibiotic-resistant infections. Culture-independent diagnostic techniques that detect pathogens and antimicrobial resistance genes within clinical samples present a tremendous benefit to timely diagnosis and management of patients. Improved outcomes for rapid intervention with rapid diagnostics have been documented and include decreased mortality rates, decreased health care delivery costs, and faster delivery of appropriate therapeutics.

Rapid Antimicrobial Susceptibility Testing Methods for Blood Cultures and Their Clinical Impact

Antimicrobial susceptibility testing (AST) of bacteria isolated in blood cultures is critical for optimal management of patients with sepsis. This review describes new and emerging phenotypic and genotypic AST methods and summarizes the evidence that implementation of these methods can impact clinical outcomes of patients with bloodstream infections.

Laboratory medicine: The exemplar for value-based healthcare

Value-Based Healthcare (VBHC) aims to improve the overall quality, safety, and sustainability of healthcare while reducing delivery costs of more effective care. Despite advantages associated with VBHC transformation, the road to its adoption has been lengthy. Laboratory Medicine (LM) is in a prime position to lead the transition to VBHC because of its key role in diagnosis and treatment of patients. Laboratory medicine results inform/influence 50% to 70% of all clinical decisions. This article summarizes some issues associated with adoption of VBHC and related healthcare innovations and suggests potential approaches using LM-specific examples to help accelerate adoption. Laboratory medicine is both a useful model for VBHC implementation and facilitator for related innovation adoption by helping to target patient populations that would benefit most from specific interventions. The critical value of rapidly adopted diagnostic technologies used during the COVID-19 pandemic and economic recovery provide important insights about the need to embrace and accelerate VBHC implementation.

Laboratory Automation in the Microbiology Laboratory: an Ongoing Journey, Not a Tale?

Clinical chemistry laboratories implemented fully automated devices decades before microbiologists started their subtle approaches to follow. Meanwhile several papers have been published about reduced time to reports, faster workflows, and increased sensitivity as results of lab automation. While the journey of automating microbiology workflows step by step was fascinating and beneficial, monetary aspects were uncommon in most publications. In this issue of the Journal of Clinical Microbiology, K. Culbreath, H. Piwonka, J. Korver, and M. Noorbakhsh (J Clin Microbiol 59:e01969-20, https://doi.org/10.1128/JCM.01969-20) calculate the benefits of total lab automation in terms of cost savings and lab efficiency in a "tale of four laboratories." The authors here provide facts and solid calculations about the benefits achieved in four different-sized labs after implementation of full laboratory automation.

Bibliometric analysis of peer-reviewed literature on antimicrobial stewardship from 1990 to 2019

BACKGROUND

The World Health Organization recommended the implementation of antimicrobial stewardship (AMS) in the clinical settings to minimize the development and spread of antimicrobial resistance (AMR). The current study aimed to assess global research activity on AMS as one measure for efforts dedicated to contain AMR.

METHOD

A bibliometric method was applied using Scopus. A validated search query was implemented. Bibliometric indicators and mapping were generated. The study period was from 1990 to 2019. The search query utilized the keywords "antimicrobial stewardship" or "antibiotic stewardship" in the titles or abstracts. In addition, documents with the term "restrict" or "restriction" if used with the terms "antimicrobial" or "antibiotic" were retrieved.

RESULTS

The search query returned 4402 documents. The keyword "antimicrobial stewardship" returned 2849 documents while the keyword "antibiotic stewardship" returned 1718 documents. The terms restrict/restriction and antimicrobial/antibiotics returned 209 documents. The number of publications and cumulative citations showed a steep and parallel increase in the last decade. The region of the Americas returned the most while the Eastern Mediterranean region returned the least. The United States (n = 1834, 41.7%) ranked first. Main research themes in the retrieved literature were the (1) impact of AMS on hospital length stay, (2) role of pharmacists, and (3) development of resistance of various pathogens. Clostridium difficile (n = 94) and Staphylococcus aureus (n = 76) were among the most frequently encountered author keywords. The Infection Control and Hospital Epidemiology journal ranked first (n = 245, 5.6%, h-index = 134) while documents published in the Clinical Infectious Diseases journal (h-index = 321) received the highest number of citations per document (70.7). At the institutional level, the US Centers for Disease Prevention and Control (n = 93, 2.1%) ranked first followed by the Imperial College London (n = 86, 2.0%). The main funding sponsors were the National Institute of Health. Pfizer, Merck, and Bayer pharmaceutical companies played a key role in funding AMS research. International research collaboration between developed (n = 3693, 83.9%) and developing countries (n = 759, 17.2%).

CONCLUSION

The fight against AMR is a global responsibility and implementation of AMS need to be carried out across the globe. International research collaboration between developing and developed countries should be encouraged.

Clinical and economical improvements after introducing rapid identification of bacteria and early antibiotic susceptibility testing in sepsis and bloodstream infections. Results of the PHENOMENON study

Background: Sepsis and bloodstream infections pose severe challenges in intensive care. Early reliable diagnosis is the key to successful therapy. The objective of the study presented here was to investigate the clinical and economical effects of the new Pheno^TM BC test, which allows bacteria identification (ID) and antimicrobial susceptibility testing (AST) in approximately 7 hours after a blood culture becomes positive (BC+). Methods: Historically controlled interventional study. Population: patients with BC+ and ICU admission. Inadequate initial antimicrobial therapy (IAT) is need of therapy change based on result. Prospectively the new test was used in addition. Primary endpoint: time-to-result in hours. Contribution margin (CM) i.e. revenue - costs was computed. All patients formed the intention-to-treat population (ITT). Patients with complete cost data formed the modified ITT group (mITT). CM results were calculated for mITT and PP. Further analyses: length-of-stay (LOS) and mortality. Results: 223 historical and 200 prospective patients were included. Time to result (ITT) was shortened by 51.1 hours (83 vs. 31.9; p<0.001). Overall savings (mITT) were 257,100 € (-301,264 € vs. -44,164 €). 143 of 181 (79%) patients had a test performed, 126 of 143 (88%) having a clinically useable result. 40 (32%) had IAT vs. 65 (29%) in the historic cohort. Median time to AST in PP was shortened by 61.7 hours (89.5 vs. 27.8; p<0.001). LOS was shortened 7 days (28 vs. 19; p=0.226) and mortality was 8% (40.5% vs. 32.5%; p=0.440) lower. Median CM +3,074.80 € per case (-2,350.50 € vs. +724.70 €; p=0.040). Conclusion: The new Pheno^TM ID+AST test leads to faster and clinically meaningful results and saves money by shortening LOS on the ICU.

A Narrative Review of Antimicrobial Stewardship Interventions within In-patient Settings and Resultant Patient Outcomes

The overuse of antibiotics has led to various healthcare problems such as the emergence of resistance in infectious microbes and mortality due to antibiotic resistant healthcare associated infections (HAIs). An antimicrobial stewardship (AMS) program is the set of interventions used worldwide to enhance the rational use of antibiotics especially for the hospitalized patients. This review aimed to describe the characteristics of the implemented AMS programs in various hospitals of the world mainly focusing on the interventions and patients outcomes. The literature about AMS program was searched through various databases such as PubMed, Google Scholar, Science Direct, Cochran Library, Ovid (Medline), Web of Science and Scopus. In this review the literature pertaining to the AMS programs for hospitalized patients is sorted on the basis of various interventions that are categorized as formulary restriction (pre-authorization), guideline development, clinical pathway development, educative interventions and prospective audit. Moreover a clear emphasis is laid on the patient outcomes obtained as a result of these interventions namely the infection control, drop in readmission rate, mortality control, resistance control and the control of an overall cost of antibiotic treatment obtained mainly by curbing the overuse of antibiotics within the hospital wards. AMS program is an efficient strategy of pharmacovigilance to rationalize the antimicrobial practice for hospitalized patients as it prevents the misuse of antibiotics, which ultimately retards the health threatening effects of various antibiotics.

Panels and Syndromic Testing in Clinical Microbiology

Syndromic panels have allowed clinical microbiology laboratories to rapidly identify bacteria, viruses, fungi, and parasites and are now fully integrated into the standard testing practices of many clinical laboratories. To maximize the benefit of syndromic testing, laboratories must implement strict measures to ensure that syndromic panels are being used responsibly. This article discusses commercially available syndromic panels, the benefits and limitations of testing, and how diagnostic and laboratory stewardship can be used to optimize testing and improve patient care while keeping costs at a minimum.

Comparison of Accelerate PhenoTest BC Kit and MALDI-TOF MS/VITEK 2 System for the rapid identification and antimicrobial susceptibility testing of gram-negative bacilli causing bloodstream infections

BACKGROUND

Our laboratory uses matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI) and the VITEK 2 system (DV2) directly from positive blood cultures (BC) for organism identification (ID) and antimicrobial susceptibility testing (AST). Our objective was to compare direct MALDI-DV2 with a commercial BC ID-AST platform, the Accelerate Pheno system (AXDX), in the ID-AST of clinical and seeded BC positive for gram-negative bacilli (GNB).

METHODS

BC positive for GNB were collected over a 3-mo period and tested using AXDX and direct MALDI-DV2 and compared with conventional methods. A subset of sterile BC were seeded with multi-drug-resistant GNB.

RESULTS

Twenty-nine clinical samples and 35 seeded samples were analyzed. Direct MALDI had a higher ID failure rate (31.0%) than AXDX (3.4%; p < 0.001). Time to ID-AST was 1.5-6.9 h, 5.8-16.5 h, and 21.6-33.0 h for AXDX, direct MALDI-DV2, and conventional methods, respectively (p < 0.001). For clinical samples, AXDX and DV2 had essential agreement (EA) or categorical agreement (CA) of more than 96%. For seeded samples, AXDX had EA, CA, VME, ME, and minor error (mE) of 93.2%, 89.0%, 2.2%, 0%, and 9.2%, respectively. AXDX had a large number of non-reports (6.1%) stemming from meropenem testing. DV2 had EA, CA, VME, ME, and mE of 97.5%, 94.7%, 1.3%, 0%, and 4.1%, respectively.

CONCLUSIONS

Direct MALDI-DV2 and AXDX both had high agreement for clinical samples, but direct MALDI-DV2 had higher agreement when challenged with MDR GNB.

Advances in rapid diagnostics for bloodstream infections

Septicemia from bloodstream infections (BSI) is the second largest cause of inpatient mortality and the single most expensive condition for US hospitals to manage. There has been an explosive development of commercial diagnostic systems to accelerate the identification and antimicrobial susceptibility testing (AST) of causative pathogens. Despite adoption of advanced technologies like matrix-assisted laser desorption imaging-time-of-flight mass spectrometry and multiplex polymerase chain reaction for rapid identification, clinical impact has been variable, in part due to the persistent need for conventional AST as well as prescriber understanding of these rapidly evolving platforms. Newer technologies are expanding on rapid detection of genotypic determinants of resistance, but only recently has rapid phenotypic AST been available. Yet, improved outcomes with rapid diagnostic platforms are still most evident in conjunction with active antimicrobial stewardship. This review will outline key advancements in rapid diagnostics for BSI and the role of antimicrobial stewardship in this new era.

Impact of Rapid Antimicrobial Susceptibility Testing in Gram-Negative Rod Bacteremia: a Quasi-experimental Study

Clinical justification for rapid antimicrobial susceptibility testing (AST) in Gram-negative rod (GNR) bacteremia is compelling; however, evidence supporting its value is sparse. We investigated the impact of rapid AST on clinical and antimicrobial stewardship outcomes in real-world practice. We performed a before-and-after quasi-experimental study from February 2018 to July 2019 at a tertiary hospital of the 24-h/day, 7-day/week implementation of the direct Vitek 2 AST method from positive blood culture broth for GNR bacteremia with electronic isolate-specific de-escalation comments and daytime antibiotic stewardship program (ASP) intervention. The primary outcome was time to appropriate antibiotic escalation or de-escalation, and secondary outcomes included time to oral antibiotic stepdown, hospital length of stay (LOS), all-cause 30-day mortality, 7-day incidence of acute kidney injury (AKI), and 30-day incidence of Clostridioides difficile infection (CDI). A total of 671 GNR isolates were included from 643 adult patients. Among patients for whom antibiotic change occurred after rapid AST result, rapid AST was associated with a trend in decreased time to escalation or de-escalation (hazard ratio, 1.22; 95% confidence interval [CI], 0.99 to 1.51; P = 0.06), with median times of 52.3 versus 42.2 h. Secondary outcomes were similar in both groups and include median time to oral antibiotic stepdown, LOS, all-cause mortality, and incidence of AKI and CDI. Rapid AST led to improved stewardship measures but did not impact clinical patient outcomes. These results highlight that multiple variables in addition to the timing of the AST result contribute to clinical outcome and that further intervention may be required to clinically justify rapid AST implementation.

Rapid isolation of rare targets from large fluid volumes

Rapidly isolating rare targets from larger, clinically relevant fluid volumes remains an unresolved problem in biomedicine and diagnosis. Here, we describe how 3D particle sorting can enrich targets at ultralow concentrations over 100-fold within minutes not possible with conventional approaches. Current clinical devices based on biochemical extraction and microfluidic solutions typically require high concentrations and/or can only process sub-milliliter volumes in time. In a proof-of-concept application, we isolated bacteria from whole blood as demanded for rapid sepsis diagnosis where minimal numbers of bacteria need to be found in a 1–10 mL blood sample. After sample encapsulation in droplets and target enrichment with the 3D particle sorter within a few minutes, downstream analyses were able to identify bacteria and test for antibiotic susceptibility, information which is critical for successful treatment of bloodstream infections.

Optical microscopy reveals the dynamic nature of B. pseudomallei morphology during β-lactam antimicrobial susceptibility testing

Background

In Gram-negative species, β-lactam antibiotics target penicillin binding proteins (PBPs) resulting in morphological alterations of bacterial cells. Observations of antibiotic-induced cell morphology changes can rapidly and accurately differentiate drug susceptible from resistant bacterial strains; however, resistant cells do not always remain unchanged. Burkholderia pseudomallei is a Gram-negative, biothreat pathogen and the causative agent of melioidosis, an often fatal infectious disease for humans.

Results

Here, we identified β-lactam targets in B. pseudomallei by in silico analysis. Ten genes encoding putative PBPs, including PBP-1, PBP-2, PBP-3 and PBP-6, were detected in the genomes of susceptible and resistant strains. Real-time, live-cell imaging of B. pseudomallei strains demonstrated dynamic morphological changes in broth containing clinically relevant β-lactam antibiotics. At sub-inhibitory concentrations of ceftazidime (CAZ), amoxicillin-clavulanic acid (AMC), and imipenem (IPM), filamentation, varying in length and proportion, was an initial response of the multidrug-resistant strain Bp1651 in exponential phase. However, a dominant morphotype reemerged during stationary phase that resembled cells unexposed to antibiotics. Similar morphology dynamics were observed for AMC-resistant strains, MSHR1655 and 724644, when exposed to sub-inhibitory concentrations of AMC. For all B. pseudomallei strains evaluated, increased exposure time and exposure to increased concentrations of AMC at and above minimal inhibitory concentrations (MICs) in broth resulted in cell morphology shifts from filaments to spheroplasts and/or cell lysis. B. pseudomallei morphology changes were more consistent in IPM. Spheroplast formation followed by cell lysis was observed for all strains in broth containing IPM at concentrations greater than or equal to MICs, however, the time to cell lysis was variable. B. pseudomallei cell lengths were strain-, drug- and drug concentration-dependent.

Conclusions

Both resistant and susceptible B. pseudomallei strains exhibited filamentation during early exposure to AMC and CAZ at concentrations used to interpret susceptibility (based on CLSI guidelines). While developing a rapid β-lactam antimicrobial susceptibility test based on cell-shape alone requires more extensive analyses, optical microscopy detected B. pseudomallei growth attributes that lend insight into antibiotic response and antibacterial mechanisms of action.

Multicenter evaluation of a syndromic rapid multiplex PCR test for early adaptation of antimicrobial therapy in adult patients with pneumonia

Background

Improving timeliness of pathogen identification is crucial to allow early adaptation of antibiotic therapy and improve prognosis in patients with pneumonia. We evaluated the relevance of a new syndromic rapid multiplex PCR test (rm-PCR) on respiratory samples to guide empirical antimicrobial therapy in adult patients with community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), and ventilator-acquired pneumonia (VAP).

Methods

This retrospective multicenter study was conducted in four French university hospitals. Respiratory samples were obtained from patients with clinical and radiological signs of pneumonia and simultaneously tested using conventional microbiological methods and the rm-PCR. A committee composed of an intensivist, a microbiologist, and an infectious diseases specialist retrospectively assessed all medical files and agreed on the most appropriate antimicrobial therapy for each pneumonia episode, according to the results of rm-PCR and blinded to the culture results. The rm-PCR-guided antimicrobial regimen was compared to the empirical treatment routinely administered to the patient in standard care.

Results

We included 159 pneumonia episodes. Most patients were hospitalized in intensive care units (n = 129, 81%), and episodes were HAP (n = 68, 43%), CAP (n = 54, 34%), and VAP (n = 37, 23%). Conventional culture isolated ≥ 1 microorganism(s) at significant level in 95 (60%) patients. The syndromic rm-PCR detected at least one bacteria in 132 (83%) episodes. Based on the results of the rm-PCR, the multidisciplinary committee proposed a modification of the empirical therapy in 123 (77%) pneumonia episodes. The modification was a de-escalation in 63 (40%), an escalation in 35 (22%), and undetermined in 25 (16%) patients. In microbiologically documented episodes (n = 95), the rm-PCR increased appropriateness of the empirical therapy to 83 (87%), as compared to 73 (77%) in routine care.

Conclusions

Use of a syndromic rm-PCR test has the potential to reduce unnecessary antimicrobial exposure and increase the appropriateness of empirical antibiotic therapy in adult patients with pneumonia.

Clinical Impact of Accelerate PhenoTM Rapid Blood Culture Detection System in Bacteremic Patients

BACKGROUND

Accelerate Pheno blood culture detection system (AXDX) provides identification (ID) and antimicrobial susceptibility testing (AST) results within 8h of blood culture growth. Limited data exists regarding its clinical impact. Other rapid platforms coupled with antimicrobial stewardship program (ASP) real-time notification (RTN) have shown improved length of stay (LOS) in bacteremia.

METHODS

A single-center, quasi-experimental study of adult bacteremic inpatients before/after AXDX implementation was conducted comparing clinical outcomes from 1 historical and 2 intervention cohorts (AXDX and AXDX+RTN). Primary outcome was LOS.

RESULTS

Of 830 bacteremic episodes, 188 (77%) of 245 historical and 308 (155 AXDX, 153 AXDX+RTN; 65%) of 585 intervention episodes were included. Median LOS was shorter with AXDX (6.3d) and AXDX+RTN (6.7d) compared to historical (8.1d; P=0.001). Achievement of optimal therapy (AOT) was more frequent (93.6% and 95.4%) and median time to optimal therapy (TTOT) was faster (1.3d and 1.4d) in AXDX and AXDX+RTN compared to historical (84.6%, P≤0.001 and 2.4d; P≤0.001) respectively. Median antimicrobial days of therapy (DOT) was shorter in both intervention arms compared to historical (6d each vs 7d; P=0.011). Median LOS benefit was most pronounced in patients with coagulase negative Staphylococcus bacteremia (5.5d and 4.5d vs 7.2d; P=0.003) in AXDX, AXDX+RTN, and historical cohorts respectively.

CONCLUSIONS

LOS, AOT, TTOT, and total DOT significantly improved after AXDX implementation. Addition of RTN did not show further improvement over AXDX and an already active ASP. These results suggest AXDX can be integrated into healthcare systems with an active ASP even without the resources to include RTN.

Trends, Epidemiology, and Management of Multi-Drug Resistant Gram-Negative Bacterial Infections in the Hospitalized Setting

The increasing prevalence of antibiotic resistance is a threat to human health, particularly within vulnerable populations in the hospital and acute care settings. This leads to increasing healthcare costs, morbidity, and mortality. Bacteria rapidly evolve novel mechanisms of resistance and methods of antimicrobial evasion. Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii have all been identified as pathogens with particularly high rates of resistance to antibiotics, resulting in a reducing pool of available treatments for these organisms. Effectively combating this issue requires both preventative and reactive measures. Reducing the spread of resistant pathogens, as well as reducing the rate of evolution of resistance is complex. Such a task requires a more judicious use of antibiotics through a better understanding of infection epidemiology, resistance patterns, and guidelines for treatment. These goals can best be achieved through the implementation of antimicrobial stewardship programs and the development and introduction of new drugs capable of eradicating multi-drug resistant Gram-negative pathogens (MDR GNB). The purpose of this article is to review current trends in MDR Gram-negative bacterial infections in the hospitalized setting, as well as current guidelines for management. Finally, new and emerging antimicrobials, as well as future considerations for combating antibiotic resistance on a global scale are discussed.

Diagnostic Accuracy of MALDI-TOF Mass Spectrometry for the Direct Identification of Clinical Pathogens from Urine

Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) has become one of the most popular methods for the rapid and cost-effective detection of clinical pathogenic microorganisms. This study aimed to evaluate and compare the diagnostic performance of MALDI-TOF MS with that of conventional approaches for the direct identification of pathogens from urine samples. A systematic review was conducted based on a literature search of relevant databases. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and area under the summary receiver operating characteristic (SROC) curve of the combined studies were estimated. Nine studies with a total of 3920 subjects were considered eligible and included in the meta-analysis. The pooled sensitivity was 0.85 (95% CI 0.79-0.90), and the pooled specificity was 0.93 (95% CI 0.82-0.97). The PLR and NLR were 11.51 (95% CI 4.53-29.26) and 0.16 (95% CI 0.11-0.24), respectively. The area under the SROC curve was 0.93 (95% CI 0.91-0.95). Sensitivity analysis showed that the results of this meta-analysis were stable. MALDI-TOF MS could directly identify microorganisms from urine samples with high sensitivity and specificity.

Calculated parenteral initial treatment of bacterial infections: Economic aspects of antibiotic treatment

This is the seventeenth chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. This chapter analyses economic aspects of antiinfective therapy. Any treatment decision is also a cost decision. In this chapter the authors particularly analyse whether or not there is evidence that certain clinically effective strategies as Antimicrobial Stewardship programs (AMS), guideline adherent initial therapy, early diagnostics, De-escalation, sequence therapy or therapeutic drug monitoring also have benficial economic effects. These can be direct savings or shortening of length of stay to free resources.

Use of Rapid Diagnostics To Manage Pediatric Bloodstream Infections? You Bet Your ASP!

Rapid diagnostic testing (RDT) can facilitate earlier optimization of the treatment of bloodstream infections, particularly in conjunction with an effective antimicrobial stewardship program (ASP). However, the effective implementation and workflow of RDTs are still a matter of debate, particularly in a pediatric setting. In this issue of the Journal of Clinical Microbiology, L. J. Juttukonda, S. Katz, J. Gillon, J. Schmitz, and R. Banerjee (J Clin Microbiol 58:e01400-19, 2020, https://doi.org/10.1128/JCM.01400-19) investigate the impact of a multiplex, molecular RDT on changes to antimicrobial therapy in an academic children's hospital. These data reveal several factors that clinical laboratories should consider prior to the implementation of RDTs for positive blood cultures.

Impact of a Rapid Blood Culture Diagnostic Test in a Children's Hospital Depends on Gram-Positive versus Gram-Negative Organism and Day versus Night Shift

Rapid diagnostic tests (RDTs) for bloodstream infections (BSIs) decrease the time to organism identification and resistance detection. RDTs are associated with early deescalation of therapy for Gram-positive BSIs. However, it is less clear how RDTs influence antibiotic management for Gram-negative BSIs and whether RDT results are acted on during off-hours. We performed a single-center, retrospective review of children with BSI and Verigene (VG) testing at a children's hospital. Of the 301 positive cultures included in the study (196 Gram-positive, 44 Gram-negative, 32 polymicrobial, and 29 non-VG targets), the VG result had potential to impact antibiotic selection in 171 cases; among these, antibiotic changes occurred in 119 (70%) cases. For Gram-negative cultures, the Verigene result correlated with unnecessary antibiotic escalation and exposure to broader-spectrum antibiotics than needed. In contrast, for Gram-positive cultures, the VG results correlated with appropriate antibiotic selection. VG results permitted early deescalation for methicillin-susceptible Staphylococcus aureus (MSSA) (19/24 [79%]) and avoidance of antibiotics for skin contaminants (30/85 [35%]). Antibiotic changes occurred more quickly during the day than at night (4.6 versus 11.7 h, respectively; P < 0.05), and antibiotic escalations occurred more quickly than did deescalations (4.1 versus 10.1 h, P < 0.01). In a pediatric institution with a low prevalence of Gram-negative resistance, the VG RDT facilitated antibiotic optimization for Gram-positive BSIs but led to unnecessary escalation of antibiotics for Gram-negative BSIs. The time to action was slower for RDT results reported at night than during the day. Laboratories should consider these factors when implementing blood culture RDTs.

Consolidation of Clinical Microbiology Laboratories and Introduction of Transformative Technologies

Clinical microbiology is experiencing revolutionary advances in the deployment of molecular, genome sequencing-based, and mass spectrometry-driven detection, identification, and characterization assays. Laboratory automation and the linkage of information systems for big(ger) data management, including artificial intelligence (AI) approaches, also are being introduced. The initial optimism associated with these developments has now entered a more reality-driven phase of reflection on the significant challenges, complexities, and health care benefits posed by these innovations. With this in mind, the ongoing process of clinical laboratory consolidation, covering large geographical regions, represents an opportunity for the efficient and cost-effective introduction of new laboratory technologies and improvements in translational research and development. This will further define and generate the mandatory infrastructure used in validation and implementation of newer high-throughput diagnostic approaches. Effective, structured access to large numbers of well-documented biobanked biological materials from networked laboratories will release countless opportunities for clinical and scientific infectious disease research and will generate positive health care impacts. We describe why consolidation of clinical microbiology laboratories will generate quality benefits for many, if not most, aspects of the services separate institutions already provided individually. We also define the important role of innovative and large-scale diagnostic platforms. Such platforms lend themselves particularly well to computational (AI)-driven genomics and bioinformatics applications. These and other diagnostic innovations will allow for better infectious disease detection, surveillance, and prevention with novel translational research and optimized (diagnostic) product and service development opportunities as key results.

Essential role of laboratory physicians in transformation of laboratory practice and management to a value-based patient-centric model

The laboratory is a vital part of the continuum of patient care. In fact, there are few programs in the healthcare system that do not rely on ready access and availability of complex diagnostic laboratory services. The existing transactional model of laboratory "medical practice" will not be able to meet the needs of the healthcare system as it rapidly shifts toward value-based care and precision medicine, which demands that practice be based on total system indicators, clinical effectiveness, and patient outcomes. Laboratory "value" will no longer be focused primarily on internal testing quality and efficiencies but rather on the relative cost of diagnostic testing compared to direct improvement in clinical and system outcomes. The medical laboratory as a "business" focused on operational efficiency and cost-controls must transform to become an essential clinical service that is a tightly integrated equal partner in direct patient care. We would argue that this paradigm shift would not be necessary if laboratory services had remained a "patient-centric" medical practice throughout the last few decades. This review is focused on the essential role of laboratory physicians in transforming laboratory practice and management to a value-based patient-centric model. Value-based practice is necessary not only to meet the challenges of the new precision medicine world order but also to bring about sustainable healthcare service delivery.

Use of oral third generation cephalosporins and quinolones and occurrence of antibiotic-resistant strains in the neurogenic bladder (NB) outpatient setting: a retrospective chart audit

STUDY DESIGN

A retrospective chart audit.

OBJECTIVES

Neurogenic bladder (NB), a risk factor for urinary tract infection, has not been comprehensively studied in terms of antimicrobial stewardship. In this study, we studied the relationship between the use of oral third generation cephalosporins and quinolones, and the occurrence of antibiotic-resistant strains.

SETTING

Hyogo Prefectural Central Rehabilitation Hospital, Hyogo, Japan.

METHODS

We retrospectively investigated antibiotic-resistant bacteria and the amount of antibiotics prescribed in outpatients with NB caused by spinal cord injury between 2012 and 2017. We intervened in urological departments whose physicians often prescribed third generation cephalosporins and fluoroquinolone, and analyzed the number of prescriptions and the amount of Cefdinir (CFDN) and Levofloxacin (LVFX), and studied changes of ratios in antibiotic-resistant strains such as extended-spectrum β-lactamases (ESBLs) and quinolone-resistant Escherichia coli and Klebsiella pneumoniae.

RESULTS

The number of CFDN prescriptions per year significantly decreased from 463 cases to 130 cases over 6 years (p = 0.012). The number of LVFX prescriptions per year decreased from 640 cases to 171 cases (p = 0.025). The incidence rate of ESBL-producing K. pneumoniae decreased from 25% to 7% of total K. pneumoniae (p < 0.001). The incidence of LVFX-resistant E. coli and K. pneumoniae significantly decreased in 2017 compared with 2012 (p = 0.03 and p = 0.016, respectively).

CONCLUSIONS

Antimicrobial stewardship interventions decreased the use of CFDN and LVFX for outpatients with NB. Our findings suggested that the reduction in the use of third generation cephalosporins and quinolones correlates with observed decrease in the occurrence of antibiotic-resistant, ESBL-producing, and quinolone-resistant bacteria.

Antimicrobial Therapy and Antimicrobial Stewardship in Sepsis

Since sepsis was first defined, sepsis management has remained challenging. To improve mortality rates for sepsis and septic shock, an accurate diagnosis and prompt administration of appropriate antibiotics are essential. The goals of antimicrobial stewardship are to achieve optimal clinical outcomes and to ensure cost-effectiveness and minimal unintended consequences, such as toxic effects and development of resistant pathogens. A combination of inadequate diagnostic criteria for sepsis and time pressure to provide broad-spectrum antimicrobial therapy remains an obstacle for antimicrobial stewardship. Efforts such as selection of appropriate empirical antibiotics and de-escalation or determination of whether or not to stop antibiotics may help to improve a patient's clinical prognosis as well as the successful implementation of antimicrobial stewardship.

Impact of an Antimicrobial Stewardship Bundle for Uncomplicated Gram-Negative Bacteremia

BACKGROUND

Recent studies in gram-negative bacteremia (GNB) suggest that intravenous (IV) to oral (PO) switch and short treatment durations yield similar clinical outcomes and fewer adverse events. Antimicrobial stewardship program (ASP) bundled initiatives have been associated with improved clinical outcomes for bloodstream infections.

METHODS

This single-center retrospective cohort evaluation included inpatient adults from 11/2014-10/2015 and 10/2017-9/2018 with GNB. The pre-ASP period was before the establishment of an ASP program. In the post period, the ASP promoted IV-to-PO switches, avoidance of repeat blood cultures, and short treatment durations for patients with uncomplicated GNB. The primary outcome was duration of antibiotic therapy. Secondary outcomes included process measures associated with the bundle and clinical outcomes.

RESULTS

One hundred thirty-seven patients met criteria for inclusion, with 51 patients in the pre group and 86 patients in the post group. Background characteristics were similar between groups. The median duration of therapy (interquartile range) was 14 (10-16) days in the pre group and 10 days (7-14) in the post group (P < .001). The median day of IV-to-PO switch was day 5 (4-6) in the pre group vs day 4 (3-5) in the post group (P = .046). The average total hospital cost per case decreased by 27% in the post group (P = .19). Mortality rates and bacteremia recurrence were not significantly different between groups.

CONCLUSIONS

An ASP bundle for uncomplicated GNB was associated with reduced durations of therapy and earlier PO switch. These findings highlight the synergistic role of ASPs in optimizing antibiotic use and promoting patient safety.

Accurate Detection of the Four Most Prevalent Carbapenemases in E. coli and K. pneumoniae by High-Resolution Mass Spectrometry

Background

At present, phenotypic growth inhibition techniques are used in routine diagnostic microbiology to determine antimicrobial resistance of bacteria. Molecular techniques such as PCR are often used for confirmation but are indirect as they detect particular resistance genes. A direct technique would be able to detect the proteins of the resistance mechanism itself. In the present study targeted high resolution mass spectrometry assay was developed for the simultaneous detection of KPC, OXA-48-like, NDM, and VIM carbapenemases.

Methods

Carbapenemase specific target peptides were defined by comparing available sequences in GenBank. Selected peptide sequences were validated using 62 Klebsiella pneumoniae and Escherichia coli isolates containing: 16 KPC, 21 OXA-48-like, 16 NDM, 13 VIM genes, and 21 carbapenemase negative isolates.

Results

For each carbapenemase, two candidate peptides were validated. Method validation was performed in a blinded manner for all 83 isolates. All carbapenemases were detected. The majority was detected by both target peptides. All target peptides were 100% specific in the tested isolates and no peptide carry-over was detected.

Conclusion

The applied targeted bottom-up mass spectrometry technique is able to accurately detect the four most prevalent carbapenemases in a single analysis.

Rapid antimicrobial susceptibility testing on positive blood cultures through an innovative light scattering technology: performances and turnaround time evaluation

BACKGROUND

A bacteremia diagnosis with speeded-up identification and antimicrobial susceptibility testing (AST) is mandatory to adjust empirical broad-spectrum antibiotherapy and avoid the emergence of multi-resistant bacteria. Alfred 60AST (Alifax, Polverara, PD, Italy) is an innovative automated system based on light scattering measurements allowing direct AST from positive blood cultures with rapid results. In this study we aimed to evaluate the system's performances and turnaround time (TAT) compared to routine AST.

METHODS

The study was conducted during 2 non-consecutive 3-month periods at the microbiology laboratory of the Cliniques universitaires Saint-Luc. All blood cultures detected positive in the 0 AM-10 AM time frame with a pure Gram-positive cocci or Gram-negative bacilli stain were included for Alfred 60AST testing. Two customized EUCAST antibiotic panels were set up composed of 1) a "Gram-negative" panel including cefuroxime, ceftazidime Enterobacteriaceae, piperacillin-tazobactam Enterobacteriaceae, ciprofloxacine, and ceftazidime Pseudomonas 2) a "Gram-positive" panel including cefoxitin Staphylococcus aureus, cefoxitin coagulase-negative (CNS) Staphylococci and ampicillin Enterococci. Categorical agreement (CA), very major errors (VME), major errors (ME), minor errors (mE) and TAT to Alfred 60AST results were calculated in comparison with AST results obtained from direct testing on positive blood cultures with the Phoenix system (Becton Dickinson, Franklin Lakes, NJ, USA).

RESULTS

Five hundred seventy and one hundred nine antibiotics were evaluated on respectively 166 Gram-negative bacilli and 109 Gram-positive cocci included in the studied population. During the first study period regarding Gram-negative strains a CA of 89.5% was obtained with a high rate of VME (19 and 15.4% respectively) for cefuroxime and piperacillin-tazobactam Enterobacteriaceae. Considering this, Alifax reviewed these antibiotics' formulations improving Gram-negative bacilli total CA to 92.2% with no VME during the second study period. For Gram-positive cocci, total CA was 88.1% with 2.3% VME, 13.8% ME (mainly cefoxitin CNS) and 12% mE rates both study periods combined. Median TAT to AST results was 5 h with Alfred versus 12 h34 with Phoenix.

CONCLUSION

The Alfred 60AST system shows correct yet improvable microbiological performances and a major TAT reduction compared to direct automated AST testing. Clinical studies measuring the impact of the approach on antibiotic management of patients with bacteremia are recommended.

Antimicrobial Stewardship Review of Automated Candidemia Alerts Using the Epic Stewardship Module Improves Bundle-of-Care Adherence

Background

Antimicrobial stewardship interventions utilizing real-time alerting through the electronic medical record enable timely implementation of the bundle of care (BOC) for patients with severe infections, such as candidemia. Automated alerting for candidemia using the Epic stewardship module has been in place since July 2015 at our medical center. We sought to assess the impact of these alerts.

Methods

All adult inpatients with candidemia between April 1, 2011, and March 31, 2012 (pre-intervention), and June 30, 2016, and July 1, 2017 (post-intervention), were evaluated for BOC adherence. We also evaluated the impact on timeliness to initiate targeted therapy, length of stay (LOS), and 30-day mortality.

Results

Eighty-four patients were included, 42 in the pre- and 42 in the post-intervention group. Adherence to BOC was significantly improved, from 48% (pre-intervention) to 83% (post-intervention; P = .001). The median time to initiation of therapy was 4.8 hours vs 3.3 hours (P = .58), the median LOS was 24 and 18 days (P = .28), and 30-day mortality was 19% and 26% (P = .60) in the pre- and post-intervention groups, respectively.

Conclusions

Antimicrobial stewardship program review of automated alerts identifying patients with candidemia resulted in significantly improved BOC adherence and was associated with a 1.5-hour reduction in time to initiation of antifungal therapy. No significant change was observed with 30-day mortality or LOS.

Strategies for increasing diagnostic yield of community-onset bacteraemia within the emergency department: A retrospective study

Bloodstream infections (BSI) are associated with high mortality. Therefore, reliable methods of detection are of paramount importance. Efficient strategies to improve diagnostic yield of bacteraemia within the emergency department (ED) are needed. We conducted a retrospective analysis of all ED encounters in a high-volume, city-centre university hospital within Germany during a five-year study period from October 2013 to September 2018. A time-series analysis was conducted for all ED encounters in which blood cultures (BCs) were collected. BC detection rates and diagnostic yield of community-onset bacteraemia were compared during the study period (which included 45 months prior to the start of a new diagnostic Antibiotic Stewardship (ABS) bundle and 15 months following its implementation). BCs were obtained from 5,191 out of 66,879 ED admissions (7.8%). Bacteraemia was detected in 1,013 encounters (19.5% of encounters where BCs were obtained). The overall yield of true bacteraemia (defined as yielding clinically relevant pathogens) was 14.4%. The new ABS-related diagnostic protocol resulted in an increased number of hospitalised patients with BCs collected in the ED (18% compared to 12.3%) and a significant increase in patients with two or more BC sets taken (59% compared to 25.4%), which resulted in an improved detection rate of true bacteraemia (2.5% versus 1.8% of hospital admissions) without any decrease in diagnostic yield. This simultaneous increase in BC rates without degradation of yield was a valuable finding that indicated success of this strategy. Thus, implementation of the new diagnostic ABS bundle within the ED, which included the presence of a skilled infectious disease (ID) team focused on obtaining BCs, appeared to be a valuable tool for the accurate and timely detection of community-onset bacteraemia.

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.

The implementation of rapid microbial identification via MALDI-ToF reduces mortality in gram-negative but not gram-positive bacteremia

Our goals were to study the effect of rapid microbial identification (RMI) of positive blood culture on patient's outcome and to identify specific microbiological characteristics related to clinical benefit of RMI. This was a retrospective-cohort study of hospitalized, adult patients with bacteremia. The outcome of patients with bacteremia episodes was compared before vs. after the initiation of RMI. RMI was done by matrix-assisted laser desorption/ionization time-of-flight testing of microcolonies. The study included 1460 and 2710 cases in the pre- and post-intervention periods, respectively. There were similar rates of gram-negative, gram-positive, anaerobes, and polymicrobial infections, but higher rate of contaminants in the intervention period (39.9 vs. 43.7%, p = 0.019). The median time-to-identification decreased from 47.5 to 21.3 h (p < 0.001). Post-intervention, the median LOS declined from 10.83 to 9.79 days (p = 0.016), the rate of ICU transfer declined from 13.8 to 11.6% (p = 0.054), and the mortality rate declined from 20.9 to 18.3% (p = 0.047). The improvement in outcome variables remained statistically significant in multivariate analysis when performed for all episodes and non-contaminants but not for contaminants. The mortality declined in gram-negative bacteremia (20% vs. 15.5%, p = 0.005 in multivariate analysis) but not in gram-positive bacteremia (18.1% vs. 18.5%). RMI reduces mortality from gram-negative but not gram-positive bacteremia.

New Microbiological Techniques in the Diagnosis of Bloodstream Infections

BACKGROUND

When a bloodstream infection is suspected, the preliminary and definitive results of culture-based microbiological testing arrive too late to have any influence on the initial choice of empirical antibiotic treatment.

METHODS

This review is based on pertinent publications retrieved by a selective search of the literature and on the authors' clinical and scientific experience.

RESULTS

A number of technical advances now enable more rapid microbiological diagnosis of bloodstream infections. DNA- based techniques for the direct detection of pathogenic organisms in whole blood have not yet become established in routine use because of various limitations. On the other hand, matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has become available for routine use in clinical laboratories and has markedly shortened the time to diagnosis after blood samples that have been cultured in automated blood-culture systems turn positive. Further developments of this technique now enable it to be used directly for blood cultures that have been flagged positive, as well as for subcultures that have been incubated for only a short time on a solid nutrient medium. The microbial biomass of the subculture can also be used in parallel for more rapid susceptibility testing with conventional methods, or, in future, with MALDI-TOF MS.

CONCLUSION

The potential of all of these new techniques will only be realizable in practice if they are optimally embedded in the diagnostic process and if sufficient attention is paid to pre-analytical issues, particularly storage and transport times.

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.

The Role of Antibiotic Stewardship in Promoting Appropriate Antibiotic Use

Antibiotics are one of the most significant medical discoveries in human history. The widespread use of antibiotics has resulted in the emergence of antibiotic-resistant pathogens. This fact, coupled with the paucity of new antibiotic developments, has spurred efforts to combat antibiotic resistance. One of the most critical components of these efforts is antibiotic stewardship, a multidisciplinary endeavor, employing a collection of interventions in a variety of health care settings with the aim of promoting appropriate utilization of antibiotics. This article describes antibiotic stewardship programs and key practices used to minimize the development and spread of antibiotic-resistant pathogens including the optimization of antibiotic pharmacokinetics and pharmacodynamics, the application of rapid diagnostic tools, and the use of computerized provider order entry tools.

Direct antimicrobial susceptibility testing of positive blood cultures: a comparison of the Accelerate Pheno™ and VITEK® 2 systems

OBJECTIVES

To compare the performance and time-to-result (TTR) for antimicrobial susceptibility testing (AST) of positive blood cultures (PBC) using the Accelerate Pheno™ system (AXDX) and both a direct VITEK® 2 card inoculation workflow (DV2) and traditional FDA-approved VITEK® 2 workflow using subcultured isolates (V2).

METHODS

Patient samples with monomicrobial Gram-negative rod bacteremia were tested on AXDX and DV2 in tandem and compared to V2 AST results. Categorical agreement (CA) errors were adjudicated using broth microdilution. Instrumentation times and AST TTR were compared.

RESULTS

AXDX and DV2 had a CA of 93.4% and 97.4%, respectively, compared to V2. Postadjudication, AXDX, DV2, and V2 had CA of 94.7%, 95.7%, and 96.5%, respectively. Instrument run times were 6.6 h, 9.4 h, and 9.2 h, and AST TTR were 8.9 h, 12.9 h and 35.5 h, respectively.

CONCLUSIONS

AXDX and DV2 ASTs are fast and reliable, which may have significant antimicrobial stewardship implications.

Derivation and validation of a simple score to predict the presence of bacteria requiring carbapenem treatment in ICU-acquired bloodstream infection and pneumonia: CarbaSCORE

Background

The recommendations of learned societies mention risk factors for the presence of multidrug resistant bacteria in hospital-acquired infections, but they do not propose a scoring system to guide empiric antibiotic therapy. Our study was aimed at developing a simple score for predicting "the presence of bacteria requiring carbapenem treatment" in ICU-acquired bloodstream infection and pneumonia.

Methods

Between December 2011 and January 2015, we conducted a retrospective study using a prospectively collected French database of nosocomial infections in the polyvalent intensive care unit of a French university hospital. All patients with ICU-acquired bloodstream infection or pneumonia were included in the study. Bivariate and multivariate analyses were performed to develop the CarbaSCORE, and this score was internally validated.

Results

In total, 338 patients were analyzed, including 27 patients requiring carbapenem treatment. The CarbaSCORE was composed of four criteria: "presence of bloodstream infection" (as opposed to pneumonia) scored 2 points, "chronic hemodialysis" scored 4 points, "travel abroad in the last 6 months" scored 5 points, and "MDR-colonization or prior use of a β-lactam of class ≥ 3" scored 6 points. Internal validation by bootstrapping showed an area under the receiver operating characteristic curve of 0.81 [0.73-0.89]. Sensitivity was 96% at the 6-point threshold and specificity was 91% at the 9-point threshold.

Conclusions

The CarbaSCORE is a simple and efficient score for predicting the presence of bacteria requiring carbapenem treatment. Further studies are needed to test this score before it can be used in practice.

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.

Preliminary readings of antimicrobial susceptibility panels: A simple, fast and inexpensive way to detect bacterial resistance and enhance antibiotic treatment of bloodstream infections

Increasing incidence of resistant bacteria needs faster identification (ID) and antibiotic susceptibility testing (AST) in order to improve antimicrobial treatment of severe infections. We propose a preliminary reading of the AST MicroScan® panels coupled with mass spectrometry ID. A total of 157 bacterial clinical isolates were processed for routine ID and AST (in 22 cases, ID and AST were performed directly from positive blood culture bottles). For gram-negatives, data from the initial and final readings were recorded and compared [89.9% category agreement (CA), 6.9% very major errors (VME)]. In adition all the 32 ESBL producers were detected at 5.3-8.6 hours. For Staphylococcus aureus, all the 16 MRSA isolates were detected at 4.5 to 7.5 hours. Thus, we find our preliminary readings approach as a simple, inexpensive and reliable way to detect and identify the most prevalent resistant bacteria in our institution on the same day that ID/AST is performed.