scholarly journals What's in a Name? The Impact of Accurate Staphylococcus pseudintermedius Identification on Appropriate Antimicrobial Susceptibility Testing

2016 ◽  
Vol 54 (3) ◽  
pp. 516-517 ◽  
Author(s):  
Brandi M. Limbago
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Methicillin Resistance ◽  
Antimicrobial Susceptibility Testing ◽  
Robust Identification ◽  
Content Type ◽  
Staphylococcus Intermedius ◽  
Article Type ◽  
The Impact ◽  
Coagulase Positive Staphylococci

Bacteria in theStaphylococcus intermediusgroup, includingStaphylococcuspseudintermedius, often encodemecA-mediated methicillin resistance. Reliable detection of this phenotype for proper treatment and infection control decisions requires that these coagulase-positive staphylococci are accurately identified and specifically that they are not misidentified asS. aureus. As correct species level bacterial identification becomes more commonplace in clinical laboratories, one can expect to see changes in guidance for antimicrobial susceptibility testing and interpretation. The study by Wu et al. in this issue (M. T. Wu, C.-A. D. Burnham, L. F. Westblade, J. Dien Bard, S. D. Lawhon, M. A. Wallace, T. Stanley, E. Burd, J. Hindler, R. M. Humphries, J Clin Microbiol 54:535–542, 2016,http://dx.doi.org/10.1128/JCM.02864-15) highlights the impact of robust identification ofS. intermediusgroup organisms on the selection of appropriate antimicrobial susceptibility testing methods and interpretation.

scholarly journals Tailoring Antimicrobial Susceptibility Testing to Individual Species of Coagulase-Negative Staphylococci: Next Up, Staphylococcus epidermidis

2019 ◽  
Vol 57 (12) ◽  
Author(s):  
C. Paul Morris ◽  
Patricia J. Simner
Keyword(s):  
Antimicrobial Susceptibility ◽  
Staphylococcus Epidermidis ◽  
Susceptibility Testing ◽  
Methicillin Resistance ◽  
Antimicrobial Susceptibility Testing ◽  
Individual Species ◽  
Beta Lactam ◽  
Coagulase Negative Staphylococci ◽  
Content Type ◽  
Species Specific

ABSTRACT Accurate detection of methicillin resistance among staphylococci is vital for patient care. Methicillin resistance is most commonly mediated by acquisition of the mecA gene, which encodes an altered penicillin binding protein, PBP2a. Application of phenotypic methods to detect mecA-mediated beta-lactam resistance in staphylococci is becoming more complex as species-specific differences are identified among coagulase-negative staphylococci (CoNS). Previously, interpretative criteria and antimicrobial susceptibility testing (AST) methods specific to the CoNS group were used to evaluate Staphylococcus epidermidis. A manuscript by S. N. Naccache, K. Callan, C.-A. D. Burnham, M. A. Wallace, et al. (J Clin Microbiol 57:e00961-19, 2019, https://doi.org/10.1128/JCM.00961-19) details experiments revealing that S. epidermidis, the most common clinically isolated CoNS, requires tailored use of previously described methods and interpretive criteria to reliably identify the presence of mecA-mediated methicillin resistance.

scholarly journals Analysis of Whole-Genome Sequences for the Prediction of Penicillin Resistance and β-Lactamase Activity inBacillus anthracis

mSystems ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
A. S. Gargis ◽  
H. P. McLaughlin ◽  
A. B. Conley ◽  
C. Lascols ◽  
P. A. Michel ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Antimicrobial Susceptibility ◽  
Sigma Factor ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Penicillin Resistance ◽  
Whole Genome ◽  
Activity Levels ◽  
Content Type

ABSTRACTPenicillin (PEN) is a low-cost option for anthrax treatment, but naturally occurring resistance has been reported. β-Lactamase expression (bla1,bla2) inBacillus anthracisis regulated by a sigma factor (SigP) and its cognate anti-sigma factor (RsiP). Mutations leading to truncation of RsiP were previously described as a basis for PEN resistance. Here, we analyze whole-genome sequencing (WGS) data and compare the chromosomalsigP-bla1regions from 374B. anthracisstrains to determine the frequency of mutations, identify mutations associated with PEN resistance, and evaluate the usefulness of WGS for predicting PEN resistance. Few (3.5%) strains contained at least 1 of 11 different mutations insigP,rsiP, orbla1.Nine of these mutations have not been previously associated with PEN resistance. Four strains showed PEN resistance (PEN-R) by conventional broth microdilution, including 1 strain with a novel frameshift inrsiP. One strain that carries the samersiPframeshift mutation as that found previously in a PEN-R strain showed a PEN-susceptible (PEN-S) phenotype and exhibited decreasedbla1andbla2transcription. An unexpectedly small colony size, a reduced growth rate, and undetectable β-lactamase activity levels (culture supernatant and cell lysate) were observed in this PEN-S strain. Sequence analysis revealed mutations in genes associated with growth defects that may contribute to this phenotype. WhileB. anthracisrsiPmutations cannot be exclusively used to predict resistance, four of the five strains withrsiPmutations were PEN-R. Therefore, theB. anthracissigP-bla1region is a useful locus for WGS-based PEN resistance prediction, but phenotypic testing remains essential.IMPORTANCEDetermination of antimicrobial susceptibility ofB. anthracisis essential for the appropriate distribution of antimicrobial agents for postexposure prophylaxis (PEP) and treatment of anthrax. Analysis of WGS data allows for the rapid detection of mutations in antimicrobial resistance (AMR) genes in an isolate, but the presence of a mutation in an AMR gene does not always accurately predict resistance. As mutations in the anti-sigma factor RsiP have been previously associated with high-level penicillin resistance in a limited number of strains, we investigated WGS assemblies from 374 strains to determine the frequency of mutations and performed functional antimicrobial susceptibility testing. Of the five strains that contained mutations inrsiP, only four were PEN-R by functional antimicrobial susceptibility testing. We conclude that while sequence analysis of this region is useful for AMR prediction inB. anthracis, genetic analysis should not be used exclusively and phenotypic susceptibility testing remains essential.

Accelerate Pheno™ blood culture detection system: a literature review

2020 ◽  
Vol 15 (16) ◽  
pp. 1595-1605
Author(s):  
Elio Cenci ◽  
Riccardo Paggi ◽  
Giuseppe V De Socio ◽  
Silvia Bozza ◽  
Barbara Camilloni ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Detection System ◽  
Operating Time ◽  
Bloodstream Infections ◽  
Antimicrobial Susceptibility Testing ◽  
Automated System ◽  
Clinical Role ◽  
Stewardship Program ◽  
The Impact

Accelerate Pheno™ (ACC) is a fully automated system providing rapid identification of a panel of bacteria and yeasts, and antimicrobial susceptibility testing of common bacterial pathogens responsible for bloodstream infections and sepsis. Diagnostic accuracy for identification ranges from 87.9 to 100%, and antimicrobial susceptibility testing categorical agreement is higher than 91%. The present review includes peer-reviewed studies on ACC published to date. Both interventional and hypothetical studies evidenced the potential positive clinical role of ACC in the management and therapy of patients with bloodstream infections and sepsis, due to the important reduction in time to report, suggesting a crucial impact on the therapeutic management of these patients, provided the presence of a hospital antimicrobial stewardship program, a 24/7 laboratory operating time and a strict collaboration between clinical microbiologist and clinician. Further prospective multicenter studies are necessary to explore the impact of this system on mortality, length of stay and spread of multidrug-resistant organisms.

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

2020 ◽  
Vol 58 (9) ◽  
Author(s):  
Catherine Anne Hogan ◽  
Bertrand Ebunji ◽  
Nancy Watz ◽  
Kristopher Kapphahn ◽  
Joseph Rigdon ◽  
...  
Keyword(s):  
Experimental Study ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Oral Antibiotic ◽  
Gram Negative ◽  
Quasi Experimental ◽  
Multiple Variables ◽  
Secondary Outcomes ◽  
The Impact

ABSTRACT 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.

scholarly journals Pharmacist-Driven Implementation of Fast Identification and Antimicrobial Susceptibility Testing Improves Outcomes for Patients with Gram-Negative Bacteremia and Candidemia

2020 ◽  
Vol 64 (9) ◽  
Author(s):  
Sahil Sheth ◽  
Michael Miller ◽  
Angela Beth Prouse ◽  
Scott Baker
Keyword(s):  
Targeted Therapy ◽  
Antibiotic Therapy ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Gram Negative ◽  
Fast Identification ◽  
Intensity Score ◽  
Gram Negative Bacteremia ◽  
The Impact

ABSTRACT Bloodstream infections (BSI) are associated with increased morbidity and mortality, especially when caused by Gram-negative or fungal pathogens. The objective of this study was to assess the impact of fast identification-antimicrobial susceptibility testing (ID/AST) with the Accelerate Pheno system (AXDX) from May 2018 to December 2018 on antibiotic therapy and patient outcomes. A pre-post quasiexperimental study of 200 patients (100 pre-AXDX implementation and 100 post-AXDX implementation) was conducted. The primary endpoints measured were time to first antibiotic intervention, time to most targeted antibiotic therapy, and 14-day hospital mortality. Secondary endpoints included hospital and intensive care unit (ICU) length of stay (LOS), antibiotic intensity score at 96 h, and 30-day readmission rates. Of 100 patients with Gram-negative bacteremia or candidemia in each cohort, 84 in the preimplementation group and 89 in the AXDX group met all inclusion criteria. The AXDX group had a decreased time to first antibiotic intervention (26.3 versus 8.0, P = 0.003), hours to most targeted therapy (14.4 versus 9, P = 0.03), hospital LOS (6 versus 8, P = 0.002), and average antibiotic intensity score at 96 h (16 versus 12, P = 0.002). Both groups had a comparable 14-day mortality (0% versus 3.6%, P = 0.11). In this analysis of patients with Gram-negative bacteremia or candidemia, fast ID/AST implementation was associated with decreased hospital LOS, decreased use of broad-spectrum antibiotics, shortened time to targeted therapy, and an improved utilization of antibiotics within the first 96 h of therapy.

scholarly journals 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

2017 ◽  
Vol 55 (7) ◽  
pp. 2116-2126 ◽  
Author(s):  
Matthias Marschal ◽  
Johanna Bachmaier ◽  
Ingo Autenrieth ◽  
Philipp Oberhettinger ◽  
Matthias Willmann ◽  
...  
Keyword(s):  
Blood Culture ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Bloodstream Infections ◽  
Test System ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Diagnostic Tools ◽  
Gram Negative ◽  
Content Type

ABSTRACT 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.

scholarly journals Rapid Antimicrobial Susceptibility Testing Using Forward Laser Light Scatter Technology

2016 ◽  
Vol 54 (11) ◽  
pp. 2701-2706 ◽  
Author(s):  
Randall T. Hayden ◽  
Lani K. Clinton ◽  
Carolyn Hewitt ◽  
Terri Koyamatsu ◽  
Yilun Sun ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Clinical Decision Making ◽  
Susceptibility Testing ◽  
Laser Light ◽  
Accurate Determination ◽  
Antimicrobial Susceptibility Testing ◽  
Limiting Factor ◽  
Light Scatter ◽  
Content Type

The delayed reporting of antimicrobial susceptibility testing remains a limiting factor in clinical decision-making in the treatment of bacterial infection. This study evaluates the use of forward laser light scatter (FLLS) to measure bacterial growth for the early determination of antimicrobial susceptibility. Three isolates each (two clinical isolates and one reference strain) ofStaphylococcus aureus,Escherichia coli, andPseudomonas aeruginosawere tested in triplicate using two commercial antimicrobial testing systems, the Vitek2 and the MicroScan MIC panel, to challenge the BacterioScan FLLS. The BacterioScan FLLS showed a high degree of categorical concordance with the commercial methods. Pairwise comparison with each commercial system serving as a reference standard showed 88.9% agreement with MicroScan (two minor errors) and 72.2% agreement with Vitek (five minor errors). FLLS using the BacterioScan system shows promise as a novel method for the rapid and accurate determination of antimicrobial susceptibility.

scholarly journals Real Life Clinical Impact of Antimicrobial Stewardship Actions on the Blood Culture Workflow from a Microbiology Laboratory

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1511
Author(s):  
Jose Maria López-Pintor ◽  
Javier Sánchez-López ◽  
Carolina Navarro-San Francisco ◽  
Ana Maria Sánchez-Díaz ◽  
Elena Loza ◽  
...  
Keyword(s):  
Blood Culture ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Intervention Group ◽  
Real Life ◽  
Antimicrobial Susceptibility Testing ◽  
Control Group ◽  
Correct Treatment ◽  
Significant Difference ◽  
The Impact

Background: Accelerating the diagnosis of bacteremia is one of the biggest challenges in clinical microbiology departments. The fast establishment of a correct treatment is determinant on bacteremic patients’ outcomes. Our objective was to evaluate the impact of antimicrobial therapy and clinical outcomes of a rapid blood culture workflow protocol in positive blood cultures with Gram-negative bacilli (GNB). Methods: A quasi-experimental before–after study was performed with two groups: (i) control group (conventional work-protocol) and (ii) intervention group (rapid workflow-protocol: rapid identification by Matrix-Assisted Laser Desorption/Ionization-Time-Of-Flight (MALDI-TOF) and antimicrobial susceptibility testing (AST) from bacterial pellet without overnight incubation). Patients were divided into different categories according to the type of intervention over treatment. Outcomes were compared between both groups. Results: A total of 313 patients with GNB-bacteremia were included: 125 patients in the control group and 188 in the intervention. The time from positive blood culture to intervention on antibiotic treatment decreased from 2.0 days in the control group to 1.0 in the intervention group (p < 0.001). On the maintenance of correct empirical treatment, the control group reported 2.0 median days until the clinical decision, while in the intervention group was 1.0 (p < 0.001). In the case of treatment de-escalation, a significant difference between both groups (4.0 vs. 2.0, p < 0.001) was found. A decreasing trend on the change from inappropriate treatments to appropriate ones was observed: 3.5 vs. 1.5; p = 0.12. No significant differences were found between both groups on 7-days mortality or on readmissions in the first 30-days. Conclusions: Routine implementation of a rapid workflow protocol anticipates the report of antimicrobial susceptibility testing results in patients with GNB-bacteremia, decreasing the time to effective and optimal antibiotic therapy.

scholarly journals On the Consequences of Poorly Defined Breakpoints for Rifampin Susceptibility Testing of Mycobacterium tuberculosis Complex

2021 ◽  
Vol 59 (4) ◽  
Author(s):  
Claudio U. Köser ◽  
Sophia B. Georghiou ◽  
Thomas Schön ◽  
Max Salfinger
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
World Health ◽  
The European Union ◽  
Reference Standard ◽  
Resistance Mutations ◽  
Content Type ◽  
Indicator Tube

ABSTRACT In a recent report of a systematic review of critical concentrations (CCs), the World Health Organization (WHO) lowered the rifampin (RIF) CC for antimicrobial susceptibility testing (AST) of the Mycobacterium tuberculosis complex using Middlebrook 7H10 medium and the Bactec Mycobacterial Growth Indicator Tube (MGIT) 960 system from 1 to 0.5 μg/ml. The previous RIF CC for 7H10 had been in use for over half a century. Because it had served as the de facto reference standard, it contributed to the endorsement of inappropriately high CCs for other AST methods, including the U.S. Food and Drug Administration (FDA)-approved MGIT system. Moreover, this resulted in confusion about the interpretation of seven borderline resistance mutations in rpoB (i.e., L430P, D435Y, H445L, H445N, H445S, L452P, and I491F). In this issue of the Journal of Clinical Microbiology, Shea et al. (J Clin Microbiol 59:e01885-20, 2021, https://doi.org/10.1128/JCM.01885-20) provide evidence that the CC endorsed by the Clinical and Laboratory Standards Institute for the Sensititre MYCOTB system, which is not FDA approved but is CE-IVD marked in the European Union, is likely also too high. These findings underscore the importance of calibrating AST methods against a rigorously defined reference standard, as recently proposed by the European Committee on Antimicrobial Susceptibility Testing, as well as the value of routine next-generation sequencing for investigating discordant AST results.

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