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

Acute myeloid leukemia and the infectious diseases consultant

Infectious complications following treatment of acute myeloid leukemia (AML) are important causes of morbidity and mortality. The spectrum and complexity of these infections is reflected by the severe net state of immunosuppression of AML patients, that is dynamic and continuously changing, the polypharmacy, including the widespread use of anti-infectives and the complex epidemiology of severe and frequently resistant pathogens afflicting these patients. Infectious diseases (ID) consultants having a critical mass of expertise and intimate knowledge of the intricacies of leukemia care, add considerable value in improving outcomes of patients with AML who develop infections. Furthermore, pharmaco-economic considerations such as length of stay, choice of cost-effective anti-infective program, infection control and antibiotic stewardship strategies create a delicate interplay of the ID consultant and the ecosystem of care of AML patients. This is an increasingly recognized area of cross collaboration and a productive direction for future collaborative practice models and research.

Pharmacist-driven antimicrobial stewardship in intensive care units in East China: A multicenter prospective cohort study

BACKGROUND

Antimicrobial stewardship programs, particularly pharmacist-driven programs, help reduce the unnecessary use of antimicrobial agents. The objective of this study was to assess the influence of pharmacist-driven antimicrobial stewardship on antimicrobial use, multidrug resistance, and patient outcomes in adult intensive care units in China.

METHOD

We conducted a multicenter prospective cohort study with a sample of 577 patients. A total of 353 patients were included under a pharmacist-driven antimicrobial stewardship program, whereas the remaining 224 patients served as controls. The primary outcome was all-cause hospital mortality.

RESULTS

The pharmacist-driven antimicrobial stewardship program had a lower hospital mortality rate compared with the nonpharmacist program (19.3% vs 29.0%; P = .007). Furthermore, logistic regression analysis indicated that the pharmacist-driven program independently predicted hospital mortality (odds ratio, 0.57; 95% confidence interval, 0.36-0.91; P = .017) after adjustment. Meanwhile, this strategy had a lower rate of multidrug resistance (23.8% vs 31.7%; P = .037). Moreover, the strategy optimized antimicrobial use, such as having a shorter duration of empirical antimicrobial therapy (2.7 days; interquartile range [IQR], 1.7-4.6 vs 3.0; IQR, 1.9-6.2; P = .002) and accumulated duration of antimicrobial treatment (4.0; IQR, 2.0-7.0 vs 5.0; IQR, 3.0-9.5; P = .030).

CONCLUSIONS

Pharmacist-driven antimicrobial stewardship in an intensive care unit decreased patient mortality and the emergence of multidrug resistance, and optimized antimicrobial agent use.

Clinical Impact and Provider Acceptability of Real-Time Antimicrobial Stewardship Decision Support for Rapid Diagnostics in Children With Positive Blood Culture Results

BACKGROUND

Rapid diagnostic technologies for infectious diseases have the potential to improve clinical outcomes, but guideline-recommended antimicrobial stewardship (AS) strategies are not currently optimized for rapid intervention. We evaluated the clinical impact and provider acceptability of implementing real-time AS decision support for children with positive blood culture results according to the FilmArray blood culture identification panel (BCID [BioFire Diagnostics]) at Children's Hospital Colorado.

METHODS

A pre-post quasi-experimental design was used to compare the outcomes of 100 postintervention children with positive blood culture results matched with 200 preintervention control children. Causative organisms in the preintervention group were identified using conventional microbiologic techniques and communicated to providers by a microbiology technologist. Postintervention organisms were identified by the BCID and communicated by an AS provider in real time with interpretation and antimicrobial recommendations. The primary outcome was time to optimal antimicrobial therapy (time from blood culture collection to start of predetermined pathogen-specific regimen or antimicrobial discontinuation for contaminants) compared by a log-rank test and Kaplan-Meier analysis. Provider acceptability of the intervention was assessed via E-mailed surveys.

RESULTS

The median time to optimal therapy decreased from 60.2 hours before intervention to 26.7 hours after intervention (P = .001). Among children with blood cultures that contained true pathogens, the time to effective antimicrobial therapy decreased from 6.9 to 3.4 hours (P = .03). Unnecessary antibiotic initiation for children with a culture that contained organisms considered to be contaminants decreased from 76% to 26% (P < .001). Providers reported a change in management as a result of BCID results in 73% of the cases and a mean overall satisfaction rating of 4.8 on a 5-point Likert scale.

CONCLUSIONS

Real-time AS decision support for rapid diagnostics is associated with improved antimicrobial use and high satisfaction ratings by providers.

Misinterpretation of Gram Stain from the Stationary Growth Phase of Positive Blood Cultures for Brucella and Acinetobacter Species

Introduction:

Acinetobacter baumannii and Brucella species are Gram-negative organisms that are vulnerable to misinterpretation as Gram-positive or Gram-variable in blood cultures.

Objective:

We assess the random errors in gram stain interpretation to reduce the likelihood of such errors and therefore patient harm.

Methodology:

Aerobic and anaerobic blood cultures from two patients in an acute care facility in Saudi Arabia were subjected to preliminary Gram-staining. In case 1, VITEK-2 Anaerobe Identification, repeat Gram staining from a blood agar plate, Remel BactiDrop™ Oxidase test, Urea Agar urease test and real-time PCR were used to confirm presence of Brucella and absence of Coryneform species. In case 2, repeat Gram- staining from the plate and the vials, VITEK-2 Gram-Negative Identification, real-time PCR and subculture on to Columbia agar, blood agar, and MacConkey agar were carried out to identify A. baumannii.

Results:

In case 1, initially pleomorphic Gram-positive bacteria were identified. Coryneform species were suspected. Tiny growth was observed after 24 h on blood agar plates, and good growth by 48 h. Presence of Brucella species was ultimately confirmed. In case 2, preliminary Gram-stain results suggested giant Gram-positive oval cocci. Further testing over 18-24 h identified A. baumannii.

Conclusions:

Oxidase test from the plate and urease test from the culture vial is recommended after apparent identification of pleomorphic Gram-positive bacilli from blood culture, once tiny growth is observed, to distinguish Brucella from Corynebacterium species. If giant Gram-positive oval cocci are indicated by preliminary Gram-staining, it is recommended that the Gram stain be repeated from the plate after 4-6 h, or culture should be tested in Triple Sugar Iron (TSI) medium and the Gram stain repeated after 2-4 h incubation.

Cumulative Effect of an Antimicrobial Stewardship and Rapid Diagnostic Testing Bundle on Early Streamlining of Antimicrobial Therapy in Gram-Negative Bloodstream Infections

The use of rapid diagnostic tests (RDTs) enhances antimicrobial stewardship program (ASP) interventions in optimization of antimicrobial therapy. This quasi-experimental cohort study evaluated the combined impact of an ASP/RDT bundle on the appropriateness of empirical antimicrobial therapy (EAT) and time to de-escalation of broad-spectrum antimicrobial agents (BSAA) in Gram-negative bloodstream infections (GNBSI). The ASP/RDT bundle consisted of system-wide GNBSI treatment guidelines, prospective stewardship monitoring, and sequential introduction of two RDTs, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and the FilmArray blood culture identification (BCID) panel. The preintervention period was January 2010 through December 2013, and the postintervention period followed from January 2014 through June 2015. The postintervention period was conducted in two phases; phase 1 followed the introduction of MALDI-TOF MS, and phase 2 followed the introduction of the FilmArray BCID panel. The interventions resulted in significantly improved appropriateness of EAT (95% versus 91%; P = 0.02). Significant reductions in median time to de-escalation from combination antimicrobial therapy (2.8 versus 1.5 days), antipseudomonal beta-lactams (4.0 versus 2.5 days), and carbapenems (4.0 versus 2.5 days) were observed in the postintervention compared to the preintervention period (P < 0.001 for all). The reduction in median time to de-escalation from combination therapy (1.0 versus 2.0 days; P = 0.03) and antipseudomonal beta-lactams (2.2 versus 2.7 days; P = 0.04) was further augmented during phase 2 compared to phase 1 of the postintervention period. Implementation of an antimicrobial stewardship program and RDT intervention bundle in a multihospital health care system is associated with improved appropriateness of EAT for GNBSI and decreased utilization of BSAA through early de-escalation.

A stepwise introduction of a successful antimicrobial stewardship program. Experience from a tertiary care university hospital in Western, Saudi Arabia

Objectives

To analyze and evaluate the safety and cost-effectiveness of a gradually-implemented antimicrobial stewardship programs (ASP) in a tertiary care center.

Methods

Prospective data were collected from an ASP that was gradually introduced between April 2012 and December 2013 in 6 hospital departments, over successive periods of 3 months each. A multidisciplinary team supervised antibiotic use and regulated pharmacy dispensations of a list of restricted antimicrobials (RAs). Indicators were prospectively monitored and included hospital mortality as the safety indicator; incidence of multi-drug resistance (MDR) infections as the effectiveness indicator, RA cost savings as the cost-effectiveness indicator and RA consumption indicated the process implementation.

Results

Between 2012 and 2014, dispensations of RAs decreased by 67% and prescriptions by 75%; no increase in mortality rate was observed. Microbiologically, there was a decreasing trend of incidence across all monitored infections, but this was only significant for Acinetobacter baumannii (p=0.007). Cost analysis showed a decrease in expenditure for RAs, with an average monthly saving of up to 326,020USD.

Conclusions

Stepwise implementation of ASPs is a safe and cost-effective strategy for improving antibiotic prescribing practice and to reduce multi-drug resistance.

The current treatment landscape: other fungal diseases (cryptococcosis, fusariosis and mucormycosis)

Compared with major invasive mycoses such as aspergillosis and candidiasis, the antifungal stewardship management strategies of other fungal diseases have different opportunities and considerations. Cryptococcosis, fusariosis and mucormycosis are globally prevalent invasive fungal diseases (IFDs), but are not currently included in antifungal prophylaxis guidelines for immunocompromised hosts. Since the implementation of biomarkers as part of diagnostic screening strategies, the concept of pre-emptive antifungal therapy has emerged for these IFDs. Management of cryptococcosis, the most common IFD worldwide, generally utilizes a pre-emptive or therapeutic strategy that does not involve prophylaxis or empirical antifungal treatment strategies. Antifungal stewardship outcomes for cryptococcosis may vary according to the availability of local resources. Invasive fusariosis, the second-most common form of non-Aspergillus mould infection among haematological malignancy patients, can be managed with pre-emptive (or diagnostic-driven) approaches based on the monitoring of serum galactomannan (GM) antigen in increased-risk populations. The success of antimicrobial stewardship programmes in decreasing the burden of invasive fusariosis in selected patient populations depends on the development and implementation of rapid diagnostic strategies for early and appropriate administration of therapy. Mucormycosis may emerge as a breakthrough IFD in haematology or solid organ transplant recipients receiving antifungals that lack activity against Mucorales. The concept of pre-emptive antifungal therapy has thus arisen for mucormycosis in the haematology setting because of the recent availability of circulating Mucorales DNA measurement. These examples demonstrate the challenges of implementing antifungal stewardship programmes in areas with limited resources, as well as in IFDs that are difficult to diagnose and treat.

Impact of Matrix-Assisted Laser Desorption and Ionization Time-of-Flight and Antimicrobial Stewardship Intervention on Treatment of Bloodstream Infections in Hospitalized Children

BACKGROUND.

Early definitive identification of infectious pathogens coupled with antimicrobial stewardship interventions allow for targeted and timely administration of antimicrobials. We investigated the combined impact of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technology and an antimicrobial stewardship program (ASP) in pediatric patients with blood stream infections (BSIs).

METHODS.

This is a single-center study comparing a control group of patients from October 2009 to July 2010 with BSIs to a cohort of patients postimplementation of MALDI-TOF and an ASP, from October 2013 to July 2014. Primary outcome was time to optimal therapy. Secondary outcomes included time to effective therapy, 30-day all-cause mortality, 30-day readmission rate, hospital length of stay, and intensive care admission.

RESULTS.

One hundred episodes of BSIs were identified in the preintervention period, and 121 episodes were identified in the postintervention period. Time from blood culture collection to organism identification was significantly reduced in the prospective cohort compared with historical controls (18.8 vs 43.7 hours, respectively). A total of 73 ASP interventions were made on the treatment of BSIs in the postintervention period. Combined use of MALDI-TOF and ASP significantly reduced time to optimal therapy (77.0 to 54.2 hours, P < .001). In the subgroup analysis of Gram-negative bacteremia, time to effective and optimal therapy were significantly reduced (2.0 vs 0.7 hours and 146.8 vs 48.0 hours, respectively). There were no significant differences in clinical outcomes.

CONCLUSIONS.

The combined use of MALDI-TOF and ASP allows early optimization of antimicrobial therapy in pediatric inpatients with BSIs.

Evaluation of the Sepsis Flow Chip assay for the diagnosis of blood infections

Background

Blood infections are serious complex conditions that generally require rapid diagnosis and treatment. The big challenge is to reduce the time necessary to make a diagnosis with current clinical microbiological methods so as to improve the treatment given to patients.

Methods

In this study, we assess for the first time the Sepsis Flow Chip assay, which is a novel diagnostic assay for simultaneous rapid-detection of the vast majority of bloodstream pathogens, including Gram-positive and Gram-negative bacteria and fungi, in the same assay, and for the detection of most common antibiotic resistance genes. The SFC assay is based on multiplex PCR and low density DNA arrays.

Results

Positive blood cultures from 202 consecutive bacteremia patients were analyzed by SFC assay and the results were compared with the results obtained by the gold standard methodology used in clinical microbiology diagnostic laboratories (EUCAST guidelines). SFC assay overall sensitivity and specificity for bacterial identification were 93.3% and 100% respectively and sensitivity and specificity for the identification of antibiotic genetic resistance determinants were 93.6% and 100% respectively.

Conclusions

This is the first evaluation of SFC assay in clinical samples. This new method appears to be very promising by combining the high number of distinct pathogens and genetic resistance determinants identified in a single assay. Further investigations should be done to evaluate the usefulness of this assay in combination with clinical multidisciplinary groups (stewardship), in order for the results to be applied appropriately to the management of patients`infectious processes.

Evaluation of the Accelerate Pheno System for Fast Identification and Antimicrobial Susceptibility Testing from Positive Blood Cultures in Bloodstream Infections Caused by Gram-Negative Pathogens

Bloodstream infections (BSI) are an important cause of morbidity and mortality. Increasing rates of antimicrobial-resistant pathogens limit treatment options, prompting an empirical use of broad-range antibiotics. Fast and reliable diagnostic tools are needed to provide adequate therapy in a timely manner and to enable a de-escalation of treatment. The Accelerate Pheno system (Accelerate Diagnostics, USA) is a fully automated test system that performs both identification and antimicrobial susceptibility testing (AST) directly from positive blood cultures within approximately 7 h. In total, 115 episodes of BSI with Gram-negative bacteria were included in our study and compared to conventional culture-based methods. The Accelerate Pheno system correctly identified 88.7% (102 of 115) of all BSI episodes and 97.1% (102 of 105) of isolates that are covered by the system's identification panel. The Accelerate Pheno system generated an AST result for 91.3% (95 of 104) samples in which the Accelerate Pheno system identified a Gram-negative pathogen. The overall category agreement between the Accelerate Pheno system and culture-based AST was 96.4%, the rates for minor discrepancies 1.4%, major discrepancies 2.3%, and very major discrepancies 1.0%. Of note, ceftriaxone, piperacillin-tazobactam, and carbapenem resistance was correctly detected in blood culture specimens with extended-spectrum beta-lactamase-producing Escherichia coli (n = 7) and multidrug-resistant Pseudomonas aeruginosa (n = 3) strains. The utilization of the Accelerate Pheno system reduced the time to result for identification by 27.49 h (P < 0.0001) and for AST by 40.39 h (P < 0.0001) compared to culture-based methods in our laboratory setting. In conclusion, the Accelerate Pheno system provided fast, reliable results while significantly improving turnaround time in blood culture diagnostics of Gram-negative BSI.

The Use of Bloodstream Infection Mortality to Measure the Impact of Antimicrobial Stewardship Interventions: Assessing the Evidence

This review sets out to evaluate the current evidence on the impact of inappropriate therapy on bloodstream infections (BSI) and associated mortality. Based on the premise that better prescribing practices should result in better patient outcomes, BSI mortality may be a useful metric to evaluate antimicrobial stewardship (AMS) interventions. A systematic search was performed in key medical databases to identify papers published in English between 2005 and 2015 that examined the association between inappropriate prescribing and BSI mortality in adult patients. Only studies that included BSIs caused by ESKAPE (Enterococcus faecium/faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) organisms were included. Study quality was assessed using the GRADE criteria and results combined using a narrative synthesis. We included 46 studies. Inappropriate prescribing was associated with an overall increase in mortality in BSI. In BSI caused by resistant gram positive organisms, such as methicillin resistant S. aureus, inappropriate therapy resulted in up to a 3-fold increase in mortality. In BSI caused by gram negative (GN) resistant organisms a much greater impact ranging from 3 to 25 fold increase in the risk of mortality was observed. While the overall quality of the studies is limited by design and the variation in the definition of appropriate prescribing, there appears to be some evidence to suggest that inappropriate prescribing leads to increased mortality in patients due to GN BSI. The highest impact of inappropriate prescribing was seen in patients with GN BSI, which may be a useful metric to monitor the impact of AMS interventions.

Advances in Rapid Identification and Susceptibility Testing of Bacteria in the Clinical Microbiology Laboratory: Implications for Patient Care and Antimicrobial Stewardship Programs

Early availability of information on bacterial pathogens and their antimicrobial susceptibility is of key importance for the management of infectious diseases patients. Currently, using traditional approaches, it usually takes at least 48 hours for identification and susceptibility testing of bacterial pathogens. Therefore, the slowness of diagnostic procedures drives prolongation of empiric, potentially inappropriate, antibacterial therapies. Over the last couple of years, the improvement of available techniques (e.g. for susceptibility testing, DNA amplification assays), and introduction of novel technologies (e.g. MALDI-TOF) has fundamentally changed approaches towards pathogen identification and characterization. Importantly, these techniques offer increased diagnostic resolution while at the same time shorten the time-to-result, and are thus of obvious importance for antimicrobial stewardship. In this review, we will discuss recent advances in medical microbiology with special emphasis on the impact of novel techniques on antimicrobial stewardship programs.

Effect of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) Alone versus MALDI-TOF MS Combined with Real-Time Antimicrobial Stewardship Interventions on Time to Optimal Antimicrobial Therapy in Patients with Positive Blood Cultures

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) decreases the time to organism identification and improves clinical and financial outcomes. The purpose of this study was to evaluate the impact of MALDI-TOF MS alone versus MALDI-TOF MS combined with real-time, pharmacist-driven, antimicrobial stewardship (AMS) intervention on patient outcomes. This single-center, pre-post, quasiexperimental study evaluated hospitalized patients with positive blood cultures identified via MALDI-TOF MS combined with prospective AMS intervention compared to a control cohort with MALDI-TOF MS identification without AMS intervention. AMS intervention included: real-time MALDI-TOF MS pharmacist notification and prospective AMS provider feedback. The primary outcome was the time to optimal therapy (TTOT). A total of 252 blood cultures, 126 in each group, were included in the final analysis. MALDI-TOF MS plus AMS intervention significantly reduced the overall TTOT (75.17 versus 43.06 h; P < 0.001), the Gram-positive contaminant TTOT (48.21 versus 11.75 h; P < 0.001), the Gram-negative infection (GNI) TTOT (71.83 versus 35.98 h; P < 0.001), and the overall hospital length of stay (LOS; 15.03 versus 9.02 days; P = 0.021). The TTOT for Gram-positive infection (GPI) was improved (64.04 versus 41.61 h; P = 0.082). For GPI, the hospital LOS (14.64 versus 10.31 days; P = 0.002) and length of antimicrobial therapy 24.30 versus 18.97 days; P = 0.018) were reduced. For GNI, the time to microbiologic clearance (51.13 versus 34.51 h; P < 0.001), the hospital LOS (15.40 versus 7.90 days; P = 0.027), and the intensive care unit LOS (5.55 versus 1.19 days; P = 0.035) were reduced. To achieve optimal outcomes, rapid identification with MALDI-TOF MS combined with real-time AMS intervention is more impactful than MALDI-TOF MS alone.

The Added Cost of Rapid Diagnostic Testing and Active Antimicrobial Stewardship: Is It Worth It?

Rapid diagnostic testing reduces the turnaround time for pathogen identification in the clinical microbiology laboratory, but the impact on patient care and hospital costs is a matter of speculation. Patel et al. (J. Clin. Microbiol. 55:60-67, 2017, https://doi.org/10.1128/JCM.01452-16) investigate the impact of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) in conjunction with active antimicrobial stewardship to determine if implementation is indeed worth the added costs.

Cost Analysis of Implementing Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Plus Real-Time Antimicrobial Stewardship Intervention for Bloodstream Infections

Studies evaluating rapid diagnostic testing plus stewardship intervention have consistently demonstrated improved clinical outcomes for patients with bloodstream infections. However, the cost of implementing new rapid diagnostic testing can be significant, and such testing usually does not generate additional revenue. There are minimal data evaluating the impact of adding matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for rapid organism identification and dedicating pharmacy stewardship personnel time on the total hospital costs. A cost analysis was performed utilizing patient data generated from the hospital cost accounting system and included additional costs of MALDI-TOF equipment, supplies and personnel, and dedicated pharmacist time for blood culture review and of making interventions to antimicrobial therapy. The cost analysis was performed from a hospital perspective for 3-month blocks before and after implementation of MALDI-TOF plus stewardship intervention. A total of 480 patients with bloodstream infections were included in the analysis: 247 in the preintervention group and 233 in the intervention group. Thirty-day mortality was significantly improved in the intervention group (12% versus 21%, P < 0.01), and the mean length of stay was reduced, although the difference was not statistically significant (13.0 ± 16.5 days versus 14.2 ± 16.7 days, P = 0.44). The total hospital cost per bloodstream infection was lower in the intervention group ($42,580 versus $45,019). Intensive care unit cost per bloodstream infection accounted for the largest share of the total costs in each group and was also lower in the intervention group ($10,833 versus $13,727). Implementing MALDI-TOF plus stewardship review and intervention decreased mortality for patients with bloodstream infections. Despite the additional costs of implementing MALDI-TOF and of dedicating pharmacy stewardship personnel time to interventions, the total hospital costs decreased by $2,439 per bloodstream infection, for an approximate annual cost savings of $2.34 million.

Understanding the Impact of Interventions to Prevent Antimicrobial Resistant Infections in the Long-Term Care Facility: A Review and Practical Guide to Mathematical Modeling

OBJECTIVES (1) To systematically search for all dynamic mathematical models of infectious disease transmission in long-term care facilities (LTCFs); (2) to critically evaluate models of interventions against antimicrobial resistance (AMR) in this setting; and (3) to develop a checklist for hospital epidemiologists and policy makers by which to distinguish good quality models of AMR in LTCFs. METHODS The CINAHL, EMBASE, Global Health, MEDLINE, and Scopus databases were systematically searched for studies of dynamic mathematical models set in LTCFs. Models of interventions targeting methicillin-resistant Staphylococcus aureus in LTCFs were critically assessed. Using this analysis, we developed a checklist for good quality mathematical models of AMR in LTCFs. RESULTS AND DISCUSSION Overall, 18 papers described mathematical models that characterized the spread of infectious diseases in LTCFs, but no models of AMR in gram-negative bacteria in this setting were described. Future models of AMR in LTCFs require a more robust methodology (ie, formal model fitting to data and validation), greater transparency regarding model assumptions, setting-specific data, realistic and current setting-specific parameters, and inclusion of movement dynamics between LTCFs and hospitals. CONCLUSIONS Mathematical models of AMR in gram-negative bacteria in the LTCF setting, where these bacteria are increasingly becoming prevalent, are needed to help guide infection prevention and control. Improvements are required to develop outputs of sufficient quality to help guide interventions and policy in the future. We suggest a checklist of criteria to be used as a practical guide to determine whether a model is robust enough to test policy. Infect Control Hosp Epidemiol 2017;38:216-225.

What are the critical steps in processing blood cultures? A prospective audit evaluating current practice of reporting blood cultures in a centralised laboratory serving secondary care hospitals

AIMS

To assess current procedures of processing positive blood cultures against national standards with an aim to evaluate its clinical impact and to determine the utility of currently available rapid identification and susceptibility tests in processing of blood cultures.

METHODS

Blood cultures from three secondary care hospitals, processed at a centralised laboratory, were prospectively audited. Data regarding processing times, communication with prescribers, changes to patient management and mortality within 30 days of a significant blood culture were collected in a preplanned pro forma for a 4-week period.

RESULTS

Of 2206 blood cultures, 211 positive blood cultures flagged positive. Sixty-nine (3.1%) of all cultures were considered to be contaminated. Fifty per cent of blood cultures that flagged positive had a Gram stain reported within 2 hours. Two (0.99%) patients with a significant bacteraemia had escalation of antimicrobial treatment at the point of reporting the Gram stain that was subsequently deemed necessary once sensitivity results were known. Most common intervention was de-escalation of therapy for Gram-positive organisms at the point of availability of pathogen identification (25.6% in Gram positive vs 10% in Gram negative; p=0.012). For Gram-negative organisms, the most common intervention was de-escalation of therapy at the point of availability of sensitivity results (43% in Gram negatives vs 17.9% in Gram positive; p=0.0097). Overall mortality within 30 days of a positive blood culture was 10.9% (23/211). Antibiotic resistance may have contributed to mortality in four of these patients (three Gram negative and one Gram positive).

CONCLUSION

Gram stain result had the least impact on antibiotic treatment interventions (escalation or de-escalation). Tests that improve identification time for Gram-positive pathogens and sensitivity time for Gram-negative pathogens had the greatest impact in making significant changes to antimicrobial treatment.

A Retrospective Study of the Impact of Rapid Diagnostic Testing on Time to Pathogen Identification and Antibiotic Use for Children with Positive Blood Cultures

Introduction

Rapid identification of bloodstream pathogens provides crucial information that can improve the choice of antimicrobial therapy for children. Previous impact studies have primarily focused on adults. Our objective was to evaluate the impact of rapid testing in a children’s hospital on time to organism identification and antibiotic use in the setting of an established antimicrobial stewardship program.

Methods

We conducted a retrospective study over three consecutive time periods (spanning January 2013–August 2015) as our hospital sequentially introduced two rapid testing methods for positive blood cultures. An antimicrobial stewardship program was active throughout the study. In the baseline period, no rapid diagnostic methods were routinely utilized. In the second period (PNAFISH), a fluorescent in situ hybridization test was implemented for gram-positive organisms and in the third a rapid multiplex PCR (rmPCR) test was employed. For children with positive blood cultures, time to organism identification use and duration of select antimicrobial therapies were compared between periods.

Results

Positive blood cultures were analyzed. Median overall time to organism identification was 23, 11, and 0 h in the baseline, PNAFISH, and rmPCR periods, respectively (p < 0.001 for both PNAFISH and rmPCR vs. baseline). For gram-negative organisms, only rmPCR performed significantly faster than baseline (p < 0.001). The duration of vancomycin use for coagulase-negative staphylococci was shorter in both the PNAFISH and rmPCR periods (mean 31 h in the baseline period, 12 and 14 h in the PNAFISH and rmPCR periods, respectively). For MSSA bacteremia, use of vancomycin was significantly decreased only in the rmPCR period (32% of patients vs. 64 and 72% in the baseline and PNAFISH periods; mean duration of 9 h vs. 30 and 26 h). There was no difference in use or duration of broad-spectrum gram-negative therapy across the three time periods.

Conclusion

Rapid diagnostic testing for children with positive blood cultures results in faster time to identification and can influence antibiotic prescribing in the setting of active antimicrobial stewardship particularly for gram-positive pathogens.

Funding

Merck.

The challenges of multi-drug-resistance in hepatology

Antimicrobial resistance has become a major global public health security problem that needs coordinated approaches at regional, national and international levels. Antibiotic overuse and the failure of control measures to prevent the spread of resistant bacteria in the healthcare environment have led to an alarming increase in the number of infections caused by resistant bacteria, organisms that resist many (multi-drug and extensively drug-resistant strains), if not all (pan-drug-resistant bacteria) currently available antibiotics. While Gram-positive cocci resistance (methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci) shows a heterogeneous geographical distribution, extended-spectrum β-lactamase-producing Enterobacteriaceae and carbapenem-resistant Enterobacteriaceae have become pandemic worldwide and endemic in some parts of the world, respectively. Moreover, currently available therapeutic options for resistant bacteria are very limited, with very few new agents in development. Antimicrobial resistance is especially relevant in decompensated cirrhosis. Firstly, cirrhotic patients are highly susceptible to develop infections caused by resistant bacteria as risk factors of multiresistance concentrate in this population (mainly repeated hospitalizations and antibiotic exposure). Secondly, inappropriate empirical antibiotic schedules easily translate into increased morbidity (acute kidney injury, acute-on-chronic liver failure, septic shock) and hospital mortality in advanced cirrhosis. Therefore, hepatologists must face nowadays a complex clinical scenario that requires new empirical antibiotic strategies that may further spread resistance. Global, regional and local preventive measures should therefore be implemented to combat antimicrobial resistance in cirrhosis including the restriction of antibiotic prophylaxis to high-risk populations, investigation on non-antibiotic prophylaxis, stewardship programs on adequate antibiotic prescription and on increasing awareness of the problem among health professionals, and well-defined early de-escalation policies based on rapid microbiological diagnostic tests. Other infection control practices such as hand hygiene and barrier precautions are also important. Clinical impact and cost-effectiveness of epidemiological surveillance programs (periodic rectal and nasal swabs) should also be explored.

New Developments in Clinical Bacteriology Laboratories

There are a number of changes underway in modern clinical bacteriology laboratories. Panel-based molecular diagnostics are now available for numerous applications, including, but not limited to, detection of bacteria and select antibacterial resistance markers in positive blood culture bottles, detection of acute gastroenteritis pathogens in stool, and detection of selected causes of acute meningitis and encephalitis in the cerebrospinal fluid. Today, rapid point-of-care nucleic acid amplification tests are bringing the accuracy of sophisticated molecular diagnostics closer to patients. A proteomic technology, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, is enabling rapid, accurate, and cost-effective identification of bacteria, as well as fungi, recovered in cultures. Laboratory automation, common in chemistry laboratories, is now available for clinical bacteriology laboratories. Finally, there are several technologies under development, such as rapid phenotypic antimicrobial susceptibility testing, whole-genome sequencing, and metagenomic analysis for the detection of bacteria in clinical specimens. It is helpful for clinicians to be aware of the pace of new development in their bacteriology laboratory to enable appropriate test ordering, to enable test interpretation, and to work with their laboratories and antimicrobial stewardship programs to ensure that new technology is implemented to optimally improve patient care.

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

BACKGROUND

 Previous reports on molecular rapid diagnostic testing (mRDT) do not consistently demonstrate improved clinical outcomes in bloodstream infections (BSIs). This meta-analysis seeks to evaluate the impact of mRDT in improving clinical outcomes in BSIs.

METHODS

 We searched PubMed, CINAHL, Web of Science, and EMBASE through May 2016 for BSI studies comparing clinical outcomes between mRDT and conventional microbiology methods.

RESULTS

 Thirty-one studies were included with 5920 patients. The mortality risk was significantly lower with mRDT than with conventional microbiology methods (odds ratio [OR], 0.66; 95% confidence interval [CI], .54-.80), yielding a number needed to treat of 20. The mortality risk was slightly lower with mRDT in studies with antimicrobial stewardship programs (ASPs) (OR, 0.64; 95% CI, .51-.79), and non-ASP studies failed to demonstrate a significant decrease in mortality risk (0.72; .46-1.12). Significant decreases in mortality risk were observed with both gram-positive (OR, 0.73; 95% CI, .55-.97) and gram-negative organisms (0.51; .33-.78) but not yeast (0.90; .49-1.67). Time to effective therapy decreased by a weighted mean difference of -5.03 hours (95% CI, -8.60 to -1.45 hours), and length of stay decreased by -2.48 days (-3.90 to -1.06 days).

CONCLUSIONS

 For BSIs, mRDT was associated with significant decreases in mortality risk in the presence of a ASP, but not in its absence. mRDT also decreased the time to effective therapy and the length of stay. mRDT should be considered as part of the standard of care in patients with BSIs.

Antimicrobial susceptibility testing of Gram-positive and -negative bacterial isolates directly from spiked blood culture media with Raman spectroscopy

Patients suffering from bacterial bloodstream infections have an increased risk of developing systematic inflammatory response syndrome (SIRS), which can result in rapid deterioration of the patients' health. Diagnostic methods for bacterial identification and antimicrobial susceptibility tests are time-consuming. The aim of this study was to investigate whether Raman spectroscopy would be able to rapidly provide an antimicrobial susceptibility profile from bacteria isolated directly from positive blood cultures. First, bacterial strains (n = 133) were inoculated in tryptic soy broth and incubated in the presence or absence of antibiotics for 5 h. Antimicrobial susceptibility profiles were analyzed by Raman spectroscopy. Subsequently, a selection of strains was isolated from blood cultures and analyzed similarly. VITEK®2 technology and broth dilution were used as the reference methods. Raman spectra from 67 antibiotic-susceptible strains showed discriminatory spectra in the absence or at low concentrations of antibiotics as compared to high antibiotic concentrations. For 66 antibiotic-resistant strains, no antimicrobial effect was observed on the bacterial Raman spectra. Full concordance with VITEK®2 data and broth dilution was obtained for the antibiotic-susceptible strains, 68 % and 98 %, respectively, for the resistant strains. Discriminative antimicrobial susceptibility testing (AST) profiles were obtained for all bacterial strains isolated from blood cultures, resulting in full concordance with the VITEK®2 data. It can be concluded that Raman spectroscopy is able to detect the antimicrobial susceptibility of bacterial species isolated from a positive blood culture bottle within 5 h. Although Raman spectroscopy is cheap and rapid, further optimization is required, to fulfill a great promise for future AST profiling technology development.

Individualized Approaches Are Needed for Optimized Blood Cultures

Many strategies and technologies are available to improve blood culture (BC)-based diagnostics. The ideal approach to BCs varies between healthcare institutions. Institutions need to examine clinical needs and practices in order to optimize BC-based diagnostics for their site. Before laboratories consider offering rapid matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS) or expensive rapid panel-based molecular BC diagnostics, they should optimize preanalytical, analytical, and postanalytical processes and procedures surrounding BC systems. Several factors need to be considered, including local resistance rates, antibiotic prescribing patterns, patient- and provider-types, laboratory staffing, and personnel available to liaise with clinicians to optimize antibiotic use. While there is much excitement surrounding new high-technology diagnostics, cost-neutral benefits can be realized by optimizing existing strategies and using available tools in creative ways. Rapid BC diagnostics should be implemented in a manner that optimizes impact. Strategies to optimize these BC diagnostics in individual laboratories are presented here.

The Confounding Role of Antimicrobial Stewardship Programs in Understanding the Impact of Technology on Patient Care

Numerous studies have demonstrated the benefit of the combination of antimicrobial stewardship program (ASP) intervention and rapid diagnostic testing (RDT). However, few studies have attempted to study the incremental benefit of ASP and RDT, making it difficult to understand the true benefits of each intervention. This issue is discussed in the context of an article by S. H. McVane and F. S. Nolte (J Clin Microbiol 54:2476-2484, 2016, http://dx.doi.org/doi:10.1128/JCM.00996-16), with suggestions about how the findings of this study can be applied to other areas of clinical microbiology.

Antimicrobial Resistance in the Intensive Care Unit

Bacterial infections are a frequent cause of hospitalization, and nosocomial infections are an increasingly common condition, particularly within the acute/critical care setting. Infection control practices and new antimicrobial development have primarily focused on gram-positive bacteria; however, in recent years, the incidence of infections caused by gram-negative bacteria has risen considerably in intensive care units. Infections caused by multidrug-resistant (MDR) gram-negative organisms are associated with high morbidity and mortality, with significant direct and indirect costs resulting from prolonged hospitalizations due to antibiotic treatment failures. Of particular concern is the increasing prevalence of antimicrobial resistance to β-lactam antibiotics (including carbapenems) among Pseudomonas aeruginosa and Acinetobacter baumannii and, recently, among pathogens of the Enterobacteriaceae family. Treatment options for infections caused by these pathogens are limited. Antimicrobial stewardship programs focus on optimizing the appropriate use of currently available antimicrobial agents with the goals of improving outcomes for patients with infections caused by MDR gram-negative organisms, slowing the progression of antimicrobial resistance, and reducing hospital costs. Newly approved treatment options are available, such as β-lactam/β-lactamase inhibitor combinations, which significantly extend the armamentarium against MDR gram-negative bacteria.

Direct identification and susceptibility testing of positive blood cultures using high speed cold centrifugation and Vitek II system

Compared to routine isolated colony-based methods, direct testing of bacterial pellets from positive blood cultures reduces turnaround time for reporting of antibiotic susceptibility. The aim of this study was to compare the accuracy, and precision, of a rapid method for direct identification and susceptibility testing of blood cultures with the routine method used in our laboratory, using Vitek 2. A total of 60 isolates were evaluated using the candidate and the routine method. The candidate method had 100% accuracy for the identification of Gram negative bacteria, Staphylococcus and Enterococcus, 50% for Streptococcus and 33.3% for Corynebacterium species. Susceptibility testing of Gram negative isolates yielded 98-100% essential agreement. For Staphylococcus and Enterococcus isolates, essential agreement was 100% for 17 antibiotics except for moxifloxacin. Direct testing of blood culture samples with Vitek 2 produced reliable identification and susceptibility results 18-24h sooner for aerobic/anaerobic facultative Gram-negative bacteria and Gram-positive Staphylococcus and Enterococcus strains.

Assessment of Time to Clinical Response in Patients with Sepsis Treated Before and After Implementation of a Matrix-Assisted Laser Desorption Ionization Time-of-Flight Blood Culture Identification Algorithm

OBJECTIVE To evaluate time to clinical response before and after implementation of rapid blood culture identification technologies. DESIGN Before-and-after trial. SETTING Large, tertiary, urban, academic health-sciences center. PATIENTS Patients >18 years old with sepsis and concurrent bacteremia or fungemia were included in the study; patients who were pregnant, had polymicrobial septicemia, or were transferred from an outside hospital were excluded. INTERVENTION Prior to the intervention, polymerase chain reaction was used to identify Staphylococcus species from positive blood cultures, and traditional laboratory techniques were used to identify non-staphylococcal species. After the intervention, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) assay and FilmArray were also used to identify additional species. During both periods, the antimicrobial stewardship team provided prospective audit and feedback for all patients on antibiotics. RESULTS A total of 219 patients were enrolled in the study: 115 patients prior to the intervention and 104 after the intervention. The median time to clinical response was statistically significantly shorter in the postintervention group than in the preintervention group (2 days vs 4 days, respectively; P=.002). By Cox regression, the implementation of MALDI-TOF and FilmArray was associated with shorter time to clinical response (hazard ratio [HR], 1.360; 95% confidence interval [CI], 1.018-1.816). After controlling for potential confounders, the study group was not independently associated with clinical response (adjusted HR, 1.279; 95% CI, 0.955-1.713). Mortality was numerically, but not statistically significantly, lower in the postintervention group than in the preintervention group (7.6% vs 11.4%; P=.342). CONCLUSIONS In the setting of an existing antimicrobial stewardship program, implementation of MALDI-TOF and FilmArray was associated with improved time to clinical response. Further research is needed to fully describe the effect of antimicrobial stewardship programs on time to clinical response. Infect Control Hosp Epidemiol 2016;37:916-923.

Prevention and Control of Antimicrobial Resistant Healthcare-Associated Infections: The Microbiology Laboratory Rocks!

In Europe, each year, more than four milion patients acquire a healthcare-associated infection (HAI) and almost 40 thousand die as a direct consequence of it. Regardless of many stategies to prevent and control HAIs, they remain an important cause of morbidity and mortality worldwide with a significant economic impact: a recent estimate places it at the ten billion dollars/year. The control of HAIs requires a prompt and efficient identification of the etiological agent and a rapid communication with the clinician. The Microbiology Laboratory has a significant role in the prevention and control of these infections and is a key element of any Infection Control Program. The work of the Microbiology Laboratory covers microbial isolation and identification, determination of antimicrobial susceptibility patterns, epidemiological surveillance and outbreak detection, education, and report of quality assured results. In this paper we address the role and importance of the Microbiology Laboratory in the prevention and control of HAI and in Antibiotic Stewardship Programs and how it can be leveraged when combined with the use of information systems. Additionally, we critically review some challenges that the Microbiology Laboratory has to deal with, including the selection of analytic methods and the proper use of communication channels with other healthcare services.

Clinical and laboratory considerations for the rapid detection of carbapenem-resistant Enterobacteriaceae

Carbapenem resistance among the Enterobacteriaceae has become a significant clinical and public health dilemma. Rapid administration of effective antimicrobials and implementation of supplemental infection control practices is required to both improve patient outcomes and limit the spread of these highly resistant organisms. However, carbapenem-resistant Enterobacteriaceae (CRE)-infected patients are predominantly identified by routine culture methods, which take days to perform. Rapid genomic and phenotypic methods are currently available to accelerate the identification of carbapenemase-producing CRE. Effective use of these technologies is reliant on close collaboration between clinical microbiology, infection prevention, antimicrobial stewardship and infectious diseases specialists. This review discusses the performance characteristics of these technologies to date, and describes strategies for their optimal implementation.

Rapid Identification of Microorganisms by FilmArray Blood Culture Identification Panel Improves Clinical Management in Children

BACKGROUND

Blood cultures are a common investigation for children admitted to hospital. In routine practice, it takes at least 24 hours to identify an organism as a contaminant or clinically significant. FilmArray Blood Culture Identification Panel (FA-BCIP) is a multiplex polymerase chain reaction that can detect 24 pathogens within 1 hour. We assessed whether results from FA-BCIP lead to changes in clinical management in a tertiary referral paediatric hospital.

METHODS

We prospectively studied children having blood cultures taken at our tertiary children's hospital. Blood cultures were monitored and organisms identified using standard methods. FA-BCIP was performed when growth was initially detected in first positive blood cultures per episode, between January 1 and June 30, 2014. Assessment of whether the FA-BCIP result altered clinical management was made, specifically focused on antimicrobial stewardship and length of stay.

RESULTS

FA-BCIP was done on 117 positive blood cultures; 74 (63%) grew clinically significant organisms, 43 (37%) grew contaminants. FA-BCIP results were judged to alter clinical management in 63 of the 117 episodes (54%). Antimicrobials were started/altered in 23 (19%) episodes and de-escalated/withheld/stopped in 29 (25%) episodes. Ten children were discharged from hospital earlier, which saved a cumulative total of 14 bed days.

CONCLUSIONS

Rapid identification of microorganisms in pediatric blood cultures by FA-BCIP, led to changes in clinical management for half of the episodes. This improved antimicrobial stewardship and allowed early discharge from hospital for 10% of children. Future studies should focus on how best to use this technology in a cost-effective manner.

Clinical Impact of Laboratory Implementation of Verigene BC-GN Microarray-Based Assay for Detection of Gram-Negative Bacteria in Positive Blood Cultures

Gram-negative bacteremia is highly fatal, and hospitalizations due to sepsis have been increasing worldwide. Molecular tests that supplement Gram stain results from positive blood cultures provide specific organism information to potentially guide therapy, but more clinical data on their real-world impact are still needed. We retrospectively reviewed cases of Gram-negative bacteremia in hospitalized patients over a 6-month period before (n = 98) and over a 6-month period after (n = 97) the implementation of a microarray-based early identification and resistance marker detection system (Verigene BC-GN; Nanosphere) while antimicrobial stewardship practices remained constant. Patient demographics, time to organism identification, time to effective antimicrobial therapy, and other key clinical parameters were compared. The two groups did not differ statistically with regard to comorbid conditions, sources of bacteremia, or numbers of intensive care unit (ICU) admissions, active use of immunosuppressive therapy, neutropenia, or bacteremia due to multidrug-resistant organisms. The BC-GN panel yielded an identification in 87% of Gram-negative cultures and was accurate in 95/97 (98%) of the cases compared to results using conventional culture. Organism identifications were achieved more quickly post-microarray implementation (mean, 10.9 h versus 37.9 h; P < 0.001). Length of ICU stay, 30-day mortality, and mortality associated with multidrug-resistant organisms were significantly lower in the postintervention group (P < 0.05). More rapid implementation of effective therapy was statistically significant for postintervention cases of extended-spectrum beta-lactamase-producing organisms (P = 0.049) but not overall (P = 0.12). The Verigene BC-GN assay is a valuable addition for the early identification of Gram-negative organisms that cause bloodstream infections and can significantly impact patient care, particularly when resistance markers are detected.

Daily Review of Antimicrobial Use Facilitates the Early Optimization of Antimicrobial Therapy and Improves Clinical Outcomes of Patients with Bloodstream Infections

Insufficient information is available to confirm the beneficial effects of implementing an antimicrobial stewardship program in reducing mortality of patients with bloodstream infections. A single institutional cohort study was conducted to evaluate clinical outcomes after implementation of a daily review of antimicrobials used to treat patients with bloodstream infections. Subjects were allocated to groups receiving either intervention or nonintervention. After implementation of an antimicrobial stewardship program, the day from the onset of infection required to administer effective intravenous antimicrobial treatment was significantly shortened (p=0.022), and the rate of de-escalation was significantly elevated (p<0.001) compared with the nonintervention group. Further, the rate of 30-d death associated with bloodstream infection was siginificantly reduced from 11.4 to 5.4% (p=0.030) compared with the nonintervention group. The incidence of adverse events was significantly lower in the intervention group than in the nonintervention group (7.7 vs. 28.0%, p<0.001). Our present findings suggest that daily review of the use of antimicrobials was highly effective for optimizing early antimicrobial therapy and improved clinical outcomes of patients with bloodstream infections.

Controversies in Antimicrobial Stewardship: Focus on New Rapid Diagnostic Technologies and Antimicrobials

Antimicrobial stewardship programs (ASPs) are challenged with ensuring appropriate antimicrobial use while minimizing expenditures. ASPs have consistently demonstrated improved patient outcomes and significant cost reductions but are continually required to justify the costs of their existence and interventions due to the silo mentality often adopted by hospital administrators. As new technologies and antimicrobials emerge, ASPs are in a constant tug-of-war between providing optimal clinical outcomes and ensuring cost containment. Additionally, robust data on cost-effectiveness of new rapid diagnostic technologies and antimicrobials with subsequent ASP interventions to provide justification are lacking. As the implementation of an ASP will soon be mandatory for acute care hospitals in the United States, ASPs must find ways to justify novel interventions to align themselves with healthcare administrators. This review provides a framework for the justification of implementing a rapid diagnostic test or adding a new antimicrobial to formulary with ASP intervention, reviews approaches to demonstrating cost-effectiveness, and proposes methods for which ASPs may reduce healthcare expenditures via alternative tactics.

Integrating Rapid Diagnostics and Antimicrobial Stewardship in Two Community Hospitals Improved Process Measures and Antibiotic Adjustment Time

OBJECTIVE To assess the impact of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry for rapid pathogen identification directly from early-positive blood cultures coupled with an antimicrobial stewardship program (ASP) in two community hospitals. Process measures and outcomes prior and after implementation of MALDI-TOF/ASP were evaluated. DESIGN Multicenter retrospective study. SETTING Two community hospitals in a system setting, Houston Methodist (HM) Sugar Land Hospital (235 beds) or HM Willowbrook Hospital (241 beds). PATIENTS Patients ≥ 18 years of age with culture-proven Gram-negative bacteremia. INTERVENTION Blood cultures from both hospitals were sent to and processed at our central microbiology laboratory. Clinical pharmacists at respective hospitals were notified of pathogen ID and susceptibility results. RESULTS We evaluated 572 patients for possible inclusion. After pre-defined exclusion criteria, 151 patients were included in the pre-intervention group and 242 were included in the intervention group. After MALDI-TOF/ASP implementation, the mean identification time after culture positivity was significantly reduced from 32 hours (±16 hours) to 6.5 hours (±5.4 hours) (P<.001); mean time to susceptibility results was significantly reduced from 48 (±22) hours to 23 (±14) hours (P<.001); and time to therapy adjustment was significantly reduced from 75 (±59) hours to 30 (±30) hours (P<.001). Mean hospital costs per patient were $3,411 less in the intervention group compared with the pre-intervention group ($18,645 vs $15,234; P=.04). CONCLUSION This study is the first to analyze the impact of MALDI-TOF coupled with an ASP in a community hospital setting. Time to results significantly differed with the use of MALDI-TOF, and time to appropriate therapy was significantly improved with the addition of ASP.

Direct blood culturing on solid medium outperforms an automated continuously monitored broth-based blood culture system in terms of time to identification and susceptibility testing

Pathogen identification and antimicrobial susceptibility testing (AST) should be available as soon as possible for patients with bloodstream infections. We investigated whether a lysis-centrifugation (LC) blood culture (BC) method, combined with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) identification and Vitek 2 AST, provides a time advantage in comparison with the currently used automated broth-based BC system. Seven bacterial reference strains were added each to 10 mL human blood in final concentrations of 100, 10 and 1 CFU/mL. Inoculated blood was added to the Isolator 10 tube and centrifuged at 3000 g for 30 min, then 1.5 mL sediment was distributed onto five 150-mm agar plates. Growth was observed hourly and microcolonies were subjected to MALDI-TOF MS and Vitek 2 as soon as possible. For comparison, seeded blood was introduced into an aerobic BC bottle and incubated in the BACTEC 9240 automated BC system. For all species/concentration combinations except one, successful identification and Vitek 2 inoculation were achieved even before growth detection by BACTEC. The fastest identification and inoculation for AST were achieved with Escherichia coli in concentrations of 100 CFU/mL and 10 CFU/mL (after 7 h each, while BACTEC flagged respective samples positive after 9.5 h and 10 h). Use of the LC-BC method allows skipping of incubation in automated BC systems and, used in combination with rapid diagnostics from microcolonies, provides a considerable advantage in time to result. This suggests that the usefulness of direct BC on solid medium should be re-evaluated in the era of rapid microbiology.

Impact of the multiplex polymerase chain reaction in culture-positive samples on appropriate antibiotic use in patients with staphylococcal bacteremia

Rapid identification of the microorganisms in patients with bacteremia may be useful in clinical practice. We evaluated the impact of the multiplex polymerase chain reaction (PCR) on appropriate antibiotic use for patients with gram-positive cocci cluster (GPCC) bacteremia. We divided the GPCC bacteremia cases into a pre-PCR group (2010-2011) and a post-PCR group (2012-2013). A total 664 cases were included in the pre-PCR group; and 570, in the post-PCR group. In methicillin-susceptible Staphylococcus aureus (MSSA) cases, optimal antibiotics were administered earlier in the post-PCR group (77.4h versus 42.6h, P=0.035). Although the proportions of glycopeptide exposure did not differ (54.7% versus 56.7%, P=0.799), the duration of exposure decreased (69.6h versus 30.7h, P=0.004). In methicillin-resistant S. aureus cases, the time to optimal antibiotics administration did not differ (45.4h versus 43.7h, P=0.275). Multiplex PCR test significantly improved the early initiation of optimal antibiotics in MSSA bacteremia and reduced the unnecessary glycopeptide exposure.

Optimized Use of the MALDI BioTyper System and the FilmArray BCID Panel for Direct Identification of Microbial Pathogens from Positive Blood Cultures

Despite the current reliance on blood cultures (BCs), the diagnosis of bloodstream infections (BSIs) can be sped up using new technologies performed directly on positive BC bottles. Two methods (the MALDI BioTyper system and FilmArray blood culture identification [BCID] panel) are potentially applicable. In this study, we performed a large-scale clinical evaluation (1,585 microorganisms from 1,394 BSI episodes) on the combined use of the MALDI BioTyper and FilmArray BCID panel compared to a reference (culture-based) method. As a result, the causative organisms of 97.7% (1,362/1,394) of the BSIs were correctly identified by our MALDI BioTyper and FilmArray BCID-based algorithm. Specifically, 65 (5.3%) out of 1,223 monomicrobial BCs that provided incorrect or invalid identifications with the MALDI BioTyper were accurately detected by the FilmArray BCID panel; additionally, 153 (89.5%) out of 171 polymicrobial BCs achieved complete identification with the FilmArray BCID panel. Conversely, full use of the MALDI BioTyper would have resulted in the identification of only 1 causative organism in 97/171 (56.7%) of the polymicrobial cultures. By applying our diagnostic algorithm, the median time to identification was shortened (19.5 h versus 41.7 h with the reference method; P < 0.001), and the minimized use of the FilmArray BCID panel led to a significant cost savings. Twenty-six out of 31 microorganisms that could not be identified were species/genera not designed to be detected with the FilmArray BCID panel, indicating that subculture was not dispensable for a few of our BSI episodes. In summary, the fast and effective testing of BC bottles is realistically adoptable in the clinical microbiology laboratory workflow, although the usefulness of this testing for the management of BSIs remains to be established.

ID Learning Unit-Diagnostics Update: Current Laboratory Methods for Rapid Pathogen Identification in Patients With Bloodstream Infections

Diagnostic assays that rapidly identify bloodstream pathogens have the potential to improve patient outcomes and antibiotic stewardship efforts. Current tests are based on the detection of nucleic acids that are specific to a targeted pathogen or based on organism identification using mass spectrometry. Most rapid assays require a positive blood culture as their sample input and expedite pathogen identification by 24–72 hours. For those assays that also report detection of drug resistance markers, information on antimicrobial resistance is expedited by 48–96 hours. This learning unit reviews the basic principles of rapid microorganism identification assays for bloodstream infections with the aim of assisting clinicians in the interpretation and optimal utilization of test results.

[Infectious diseases as a clinical specialty in Germany and Europe]

Clinical infectious diseases have only slowly been established as a medical specialty in Germany. The density of infectious diseases (ID) specialists and the number of ID divisions in general hospitals is still limited when compared with the situation in many other European countries, and there is also a lack of hospital-based medical microbiologists and infection control doctors for many reasons. Often, there is a lack of understanding of the roles and the performance of ID specialists versus microbiologists. Experience in other countries shows that ID specialists are important as clinical experts at the bedside, can help ascertain healthcare quality and patient safety, and are perfectly suited for undertaking strategic tasks in the field of cost-effective antimicrobial therapy algorithms and antibiotic stewardship (ABS) in hospitals. ID specialists are responsible for infection control in several countries, can improve the utility of diagnostic microbiology and are key partners in translational research. We estimate that more than 1,000 additional ID specialists are needed in this country, and believe that specially trained ABS experts can take over parts of their responsibilities and tasks in smaller hospitals. More capacity and flexibility in postgraduate training in infectious diseases, antibiotic stewardship and infection control in Germany will be critical to address the problem of antimicrobial resistance. (As supplied by publisher).

Impact of rapid identification of Acinetobacter Baumannii via matrix-assisted laser desorption ionization time-of-flight mass spectrometry combined with antimicrobial stewardship in patients with pneumonia and/or bacteremia

We evaluated the clinical and economic outcomes of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) with stewardship intervention in patients with Acinetobacter baumannii (AB) pneumonia and/or bacteremia. 66 patients were included in the pre-intervention group and 53 in the intervention group. The combination of AB identification via MALDI-TOF MS and ID PharmD intervention significantly reduced the median time to effective therapy compared to conventional identification without intervention [77.7 (95% CI: 73.1-84.8) to 36.6 (95% CI: 25.9-50.9) hours (P < 0.0001)]. Rapid organism identification along with ID PharmD intervention was also associated with a 19% increase in clinical cure (15% versus 34%, P = 0.016) and a decreased length of stay during antibiotic therapy (13 [8-18] versus 11 [7-15] days, P = 0.021). No difference in 14-day mortality was observed (20% versus 25%, P = 0.526). Median costs during infection were approximately $6500 less in the intervention group ($49,402 [35,307-86,566] versus $42,872 [26,966-74,506]; P = 0.243). AB identification via MALDI-TOF MS combined with stewardship intervention allows for timely, effective antimicrobial therapy and is associated with increased clinical cure.

Considerations About Antimicrobial Stewardship in Settings with Epidemic Extended-Spectrum β-Lactamase-Producing or Carbapenem-Resistant Enterobacteriaceae

Infections caused by gram-negative bacteria (GNB) resistant to multiple classes of antibiotics are increasing in many hospitals. Extended-spectrum β-lactamase (ESBL)-producing and carbapenem-resistant Enterobacteriaceae in particular are now endemic in many parts of the world and represent a serious public health threat. In this era, antimicrobial stewardship programs are essential as targeted and responsible use of antibiotics improves patient outcomes and hopefully limits the selective pressure that drives the further emergence of resistance. However, some stewardship strategies aimed at promoting carbapenem-sparing regimens remain controversial and are difficult to implement when resistance rates to non-carbapenem antibiotics are increasing. Coordinated efforts between stewardship programs and infection control are essential for reversing conditions that favor the emergence and dissemination of multidrug-resistant GNB within the hospital and identifying extra-institutional "feeder reservoirs" of resistant strains such as long-term care facilities, where colonization is common despite limited numbers of serious infections. In settings where ESBL resistance is endemic, the cost-effectiveness of expanded infection control efforts and antimicrobial stewardship is still unknown. Once a patient has been colonized, selective oral or digestive decontamination may be considered, but evidence supporting its effectiveness is limited in patients who are already colonized or in centers with high rates of resistance. Moreover, temporary success at decolonization may be associated with a higher risk of relapse with strains that are resistant to the decolonizing antibiotics.