The American Society for Microbiology collaboration with the CDC Laboratory Medicine Best Practices initiative for evidence-based laboratory medicine.

SUMMARYClinical medicine has embraced the use of evidence for patient treatment decisions; however, the evaluation strategy for evidence in laboratory medicine practices has lagged. It was not until the end of the 20th century that the Institute of Medicine (IOM), now the National Academy of Medicine, and the Centers for Disease Control and Prevention, Division of Laboratory Systems (CDC DLS), focused on laboratory tests and how testing processes can be designed to benefit patient care. In collaboration with CDC DLS, the American Society for Microbiology (ASM) used an evidence review method developed by the CDC DLS to develop a program for creating laboratory testing guidelines and practices.

Carbapenem-Resistant Acinetobacter baumannii in U.S. Hospitals: Diversification of Circulating Lineages and Antimicrobial Resistance.

Carbapenem-resistant Acinetobacter baumannii (CR) is a major cause of health care-associated infections. CR is typically multidrug resistant, and infection is difficult to treat. Despite the urgent threat that CR poses, few systematic studies of CR clinical and molecular epidemiology have been conducted.

Multicenter Evaluation of a Gradient Diffusion Method for Antimicrobial Susceptibility Testing of Helicobacter pylori.

Helicobacter pylori is an important human pathogen associated with peptic ulcer disease, dyspepsia, and gastric malignancy. Antimicrobial susceptibility testing (AST) is often requested for patients who fail eradication therapy. The Clinical and Laboratory Standards Institute (CLSI) reference method, agar dilution (AD), is not performed in most laboratories and maintaining organism viability during transit to a reference laboratory is difficult.

Multicenter evaluation of the VITEK MS matrix-assisted laser desorption/ionization-time of flight mass spectrometry system for identification of bacteria, including Brucella, and yeasts.

The use of matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry has proven to be rapid and accurate for the majority of clinical isolates. Some gaps remain concerning rare, emerging, or highly pathogenic species, showing the need to continuously expand the databases. In this multicenter study, we evaluated the accuracy of the VITEK MS v3.

The Implementation and Effect of Weekend Pharmacy-Driven Antimicrobial Stewardship Services at a Large Academic Medical Center.

Background: In September 2018, pharmacy antimicrobial stewardship (AMS) services were expanded to include weekends at this academic medical center. Activities performed by AMS pharmacists on the weekends include blood culture rapid diagnostic (RDT) review, antiretroviral therapy (ART) review, prospective audit and feedback (PAF) utilizing clinical decision support, vancomycin dosing, and operational support. The purpose of this study was to assess the operational and clinical impact of these expanded AMS services.

Real-time polymerase chain reaction (PCR) cycle threshold and infection outcomes.

Objective: Clostridioides difficile infection (CDI) causes significant morbidity and mortality; however, the diagnosis of CDI remains controversial. The primary aim of our study was to evaluate the association of polymerase chain reaction (PCR) cycle threshold (Ct) values with CDI disease severity, recurrence, and mortality among adult patients with CDI.

Design: Retrospective cohort study.

Assessment of the Accuracy of Using ICD-9 Diagnosis Codes to Identify Pneumonia Etiology in Patients Hospitalized With Pneumonia.

Importance: Administrative databases may offer efficient clinical data collection for studying epidemiology, outcomes, and temporal trends in health care delivery. However, such data have seldom been validated against microbiological laboratory results.

Objective: To assess the validity of International Classification of Diseases, Ninth Revision (ICD-9) organism-specific administrative codes for pneumonia using microbiological data (test results for blood or respiratory culture, urinary antigen, or polymerase chain reaction) as the criterion standard.

Multicenter evaluation of the RAPIDEC® CARBA NP assay for the detection of carbapenemase production in clinical isolates of Enterobacterales and Pseudomonas aeruginosa.

Carbapenem-resistant Gram-negative bacilli are a major public health problem. Accurate and rapid detection of carbapenemase-producing organisms can facilitate appropriate infection prevention measures. The objective was to evaluate the performance of the RAPIDEC® CARBA NP assay (RAPIDEC), a screening assay that utilizes a pH indicator to detect carbapenem hydrolysis within 2 h.

De-escalation of Empiric Antibiotics Following Negative Cultures in Hospitalized Patients With Pneumonia: Rates and Outcomes.

Background: For patients at risk for multidrug-resistant organisms, IDSA/ATS guidelines recommend empiric therapy against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas. Following negative cultures, the guidelines recommend antimicrobial de-escalation. We assessed antibiotic de-escalation practices across hospitals and their associations with outcomes in hospitalized patients with pneumonia with negative cultures.

Clostridium septicum-infected aortic aneurysm or graft is a deadly diagnosis.

Background: Clostridium septicum is an anaerobic, motile, spore-forming, toxin-producing gram-positive bacillus that can lead to rapidly progressive gas gangrene due to the release of alpha toxin. Aortic aneurysm secondary to C. septicum infection is a rare condition with 60 cases reported in the literature; however, we have recently treated several patients with the condition in our large tertiary care and aortic center.

Optimal Timing of Repeat Multiplex Molecular Testing for Respiratory Viruses.

Determining whether and when multiplex nucleic acid amplification tests (NAATs) for respiratory viruses should be repeated is difficult. We analyzed 5 years of results for a multiplex NAAT targeting 14 respiratory viruses, to determine how often repeat tests were ordered and the time period in which results were likely to change. Results for NAATs performed on nasopharyngeal specimens and repeated within 90 days after initial testing were analyzed.

Prospective Evaluation of Molecular Assays for Diagnosis of Vaginitis.

Molecular tests to diagnose conditions involving the disruption of normal microbiota are difficult to optimize. Using Nugent-scored Gram stain (NS) as the reference standard, we evaluated the performance of 3 molecular assays for the diagnosis of bacterial vaginosis (BV) and examined the impact of an incremental increase in bacterial targets. The BD Affirm assay includes a DNA probe for , the Hologic transcription-mediated amplification (TMA) analyte-specific reagent (ASR) assay adds a second sp.

Pneumococcal Urinary Antigen Testing in United States Hospitals: A Missed Opportunity for Antimicrobial Stewardship.

Background: The Infectious Diseases Society of America recommends pneumococcal urinary antigen testing (UAT) when identifying pneumococcal infection would allow for antibiotic de-escalation. However, the frequencies of UAT and subsequent antibiotic de-escalation are unknown.

Methods: We conducted a retrospective cohort study of adult patients admitted with community-acquired or healthcare-associated pneumonia to 170 US hospitals in the Premier database from 2010 to 2015, to describe variation in UAT use, associations of UAT results with antibiotic de-escalation, and associations of de-escalation with outcomes.

In-Room Ultraviolet Air Filtration Units Reduce Airborne Particles During Total Joint Arthroplasty.

Reducing airborne bioburden in total joint arthroplasty (TJA) is of critical importance. The efficacy of crystalline ultraviolet-C (C-UVC) filtration in reducing bioburden in a dynamic operating room (OR) environment has not been evaluated. We assessed whether C-UVC filtration reduced (i) total particle counts (TPC); (ii) viable particle counts (VPC); and (iii) colony-forming units (CFUs).

The Pitt Bacteremia Score Predicts Mortality in Nonbacteremic Infections.

Background: Predicting mortality risk in patients is important in research settings. The Pitt bacteremia score (PBS) is commonly used as a predictor of early mortality risk in patients with bloodstream infections (BSIs). We determined whether the PBS predicts 14-day inpatient mortality in nonbacteremia carbapenem-resistant Enterobacteriaceae (CRE) infections.

A Laboratory Medicine Best Practices Systematic Review and Meta-analysis of Nucleic Acid Amplification Tests (NAATs) and Algorithms Including NAATs for the Diagnosis of () in Adults.

The evidence base for the optimal laboratory diagnosis of () in adults is currently unresolved due to the uncertain performance characteristics and various combinations of tests. This systematic review evaluates the diagnostic accuracy of laboratory testing algorithms that include nucleic acid amplification tests (NAATs) to detect the presence of The systematic review and meta-analysis included eligible studies (those that had PICO [population, intervention, comparison, outcome] elements) that assessed the diagnostic accuracy of NAAT alone or following glutamate dehydrogenase (GDH) enzyme immunoassays (EIAs) or GDH EIAs plus toxin EIAs (toxin). The diagnostic yield of NAAT for repeat testing after an initial negative result was also assessed.

Rapid Replacement of Acinetobacter baumannii Strains Accompanied by Changes in Lipooligosaccharide Loci and Resistance Gene Repertoire.

The population structure of health care-associated pathogens reflects patterns of diversification, selection, and dispersal over time. Empirical data detailing the long-term population dynamics of nosocomial pathogens provide information about how pathogens adapt in the face of exposure to diverse antimicrobial agents and other host and environmental pressures and can inform infection control priorities. Extensive sequencing of clinical isolates from one hospital spanning a decade and a second hospital in the Cleveland, OH, metropolitan area over a 3-year time period provided high-resolution genomic analysis of the metapopulation.

Targeting Multidrug-Resistant spp.: Sulbactam and the Diazabicyclooctenone β-Lactamase Inhibitor ETX2514 as a Novel Therapeutic Agent.

Multidrug-resistant (MDR) spp. poses a significant therapeutic challenge in part due to the presence of chromosomally encoded β-lactamases, including class C -derived cephalosporinases (ADC) and class D oxacillinases (OXA), as well as plasmid-mediated class A β-lactamases. Importantly, OXA-like β-lactamases represent a gap in the spectrum of inhibition by recently approved β-lactamase inhibitors such as avibactam and vaborbactam.

The Role of Trimethoprim/Sulfamethoxazole in the Treatment of Infections Caused by Carbapenem-Resistant .

In the Consortium on Resistance Against Carbapenems in and other (CRACKLE), trimethoprim-sulfamethoxazole (TMP-SMX) had a limited role in the treatment of less severe carbapenem-resistant (CRE) infections, especially urinary tract infections. Of tested CRE, only 29% were susceptible to TMP-SMX. Development of resistance further limits the use of TMP-SMX in CRE infections.

Routine Broad-Range Fungal Polymerase Chain Reaction With DNA Sequencing in Patients With Suspected Mycoses Does Not Add Value and Is Not Cost-Effective.

Context.—: New molecular diagnostic tests regularly become available, and they may be assumed to be superior to traditional diagnostic studies. The added cost of these studies should be considered in conjunction with the value provided for patient care.