Publications by authors named "Audrey N Schuetz"

91 Publications

Phenotypic and genomic profiling of in Canada and the United States and recommendations for clinical result reporting.

J Clin Microbiol 2021 Mar 17. Epub 2021 Mar 17.

Public Health Ontario, 661 University Avenue, Toronto, ON, Canada

is a newly described species, formerly known as clonal complex 75 (CC75). Here we describe the largest collection of isolates in North America, highlighting identification challenges. We present phenotypic and genomic characteristics and provide recommendations for clinical reporting. Between 2017-2019, 22 isolates of were received at 2 large reference laboratories for identification. Identification with routine methods (biochemical, MALDI-TOF MS, 16S rRNA gene analysis) proved challenging to confidently distinguish these isolates from Whole genome sequencing analysis was employed to confirm identifications. Using several different sequence-based analyses, all clinical isolates under investigation were confirmed to be with clear differentiation from Seven of 22 isolates were recovered from sterile sites, 11 from non-sterile sites, and 4 from surveillance screens. While sequence types ST1223/ type XV, ST2198/ type XIV and ST2793/ type XId were identified amongst the Canadian isolates, the majority of isolates (73%) belonged to MLST ST2250/ type XId and exhibited a high degree of homology at the genomic level. Despite this similarity, 5 -types were identified among ST2250 isolates, demonstrating some diversity between strains. Several isolates carried , as well as other resistance and virulence determinants (e.g., PVL, TSST-1) commonly associated with Based on our findings, the growing body of literature on the potential severity of infections as well as possible confusion associated with reporting, including use of incorrect breakpoints for susceptibility results, we make recommendations for clinical laboratories regarding this organism.
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http://dx.doi.org/10.1128/JCM.02470-20DOI Listing
March 2021

Multidrug-resistant Pseudomonas aeruginosa in healthcare facilities in Port-au-Prince, Haiti.

J Glob Antimicrob Resist 2021 Mar 1;25:60-65. Epub 2021 Mar 1.

Center for Global Health, Weill Cornell Medicine, New York, NY, USA.

Objectives: Pseudomonas aeruginosa is a leading cause of opportunistic infections worldwide, particularly in healthcare settings, and frequently demonstrates resistance to commonly prescribed antimicrobials. Carbapenem resistance is prevalent worldwide, however there are currently limited data available from Haiti. The aim of this study was to characterise and document this phenotype in Port-au-Prince, Haiti, to further inform the need for appropriate infection control, empirical treatment guidelines and laboratory screening measures, both in Haiti and globally.

Methods: A total of 50 P. aeruginosa isolates were characterised by multilocus sequence typing (MLST) and antimicrobial susceptibility testing, of which 8 isolates were also subjected to whole-genome sequencing (WGS) to identify potential genetic correlations of phenotypic resistance.

Results: By MLST, 23 sequence types (STs) were identified, including 13 new STs. Nineteen isolates belonged to a single, previously characterised ST (ST654), all of which demonstrated a multidrug-resistant phenotype, including resistance to meropenem, imipenem and ceftazidime; two isolates were also resistant to colistin. WGS revealed the presence of genes encoding several previously characterised resistance determinants in ST654; notably ACC(6')-Ib3-cr and GES-7. Metallo-β-lactamase genes (bla) were also detected in three isolates.

Conclusion: These findings confirm that drug-resistant clones of P. aeruginosa are present in Haiti, supporting the need for appropriate screening and control measures and confirming that drug-resistant micro-organisms pose a global threat. Further investigations are required to guide appropriate antimicrobial prescribing in this region.
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http://dx.doi.org/10.1016/j.jgar.2021.02.016DOI Listing
March 2021

All You Need to Know and More about the Diagnosis and Management of Rare Mold Infections.

mBio 2021 02 23;12(1). Epub 2021 Feb 23.

University of Cologne, Faculty of Medicine, Cologne, Germany.

Invasive mold infections caused by molds other than spp. or Mucorales are emerging. The reported prevalences of infection due to these rare fungal pathogens vary among geographic regions, driven by differences in climatic conditions, susceptible hosts, and diagnostic capabilities. These rare molds-, , and species and others-are difficult to detect and often show intrinsic antifungal resistance. Now, international societies of medical mycology and microbiology have joined forces and created the "Global guideline for the diagnosis and management of rare mould infections: an initiative of the European Confederation of Medical Mycology in cooperation with the International Society for Human and Animal Mycology and the American Society for Microbiology" (published in Lancet Infect Dis, https://doi.org/10.1016/S1473-3099(20)30784-2), with the goal of improving the diagnosis, treatment, prevention, and survival of persons with rare mold infections. The guideline provides cutting-edge guidance for the correct utilization and application of established and new diagnostic and therapeutic options.
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http://dx.doi.org/10.1128/mBio.02920-20DOI Listing
February 2021

Correlation between hemolytic profile and phylotype of (formerly ) and orthopedic implant infection.

Shoulder Elbow 2020 Dec 9;12(6):390-398. Epub 2019 Aug 9.

Mayo Clinic, Rochester, USA.

Introduction: is a recognized culprit for implant-associated infections, but positive cultures do not always indicate clinically relevant infection. Studies have shown a correlation between the β-hemolytic phenotype of and its infectious capacity, but correlation with genetic phylotype has not been performed in literature. The purpose of this study is to evaluate β-hemolysis phenotype, genetic phylotype, and mid-term clinical outcomes of isolated from orthopedic surgical sites.

Methods: Fifty-four isolates previously obtained from surgical wounds of patients undergoing hip, knee, shoulder, or spine implant removal were re-cultured. There were 21 females and 33 males with an average age of 59 years (range, 18-84). Twenty-four were from clinically infected sites whereas 30 were considered contaminants. De novo β-hemolysis was analyzed and a retrospective chart review was performed to evaluate clinical outcomes at 7.1 years (range, 0.1-12.8).

Results: On agar with 5% rabbit blood, 46% of contaminant and 43% of infectious isolates were hemolytic. Type II phylotype was significantly more nonhemolytic regardless of infectious or contaminant status (p < 0.05). Type 1B correlated with a hemolytic-infectious phenotype and Type 1A with a hemolytic-contaminant phenotype but was not statistically significant.

Conclusion: The β-hemolytic profile of did not correlate with phylotype or clinically relevant orthopedic infection.
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http://dx.doi.org/10.1177/1758573219865884DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7689609PMC
December 2020

When Should Asymptomatic Persons Be Tested for COVID-19?

J Clin Microbiol 2020 12 17;59(1). Epub 2020 Dec 17.

Department of Pathology and Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA

On 24 August 2020, the Centers for Disease Control and Prevention (CDC) updated its website to highlight that asymptomatic individuals, even those with exposure to a COVID-19-positive contact, do not necessarily need to be tested unless they have medical conditions associated with increased risk of severe illness from COVID-19. The CDC subsequently updated its guidance on 19 September 2020 to support testing of asymptomatic persons, including close contacts of persons with documented SARS-CoV-2 infection. In this editorial, the American Society for Microbiology Clinical and Public Health Microbiology Committee's Subcommittee on Laboratory Practices comments on testing of asymptomatic individuals relative to current medical knowledge of the virus and mitigation measures. Specific points are provided concerning such testing when undertaking contact tracing and routine surveillance. Limitations to consider when testing asymptomatic persons are covered, including the need to prioritize testing of contacts of positive COVID-19 cases. We urge the CDC to consult with primary stakeholders of COVID-19 testing when making such impactful changes in testing guidance.
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http://dx.doi.org/10.1128/JCM.02563-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7771439PMC
December 2020

Application, Verification, and Implementation of SARS-CoV-2 Serologic Assays with Emergency Use Authorization.

J Clin Microbiol 2020 12 17;59(1). Epub 2020 Dec 17.

Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA

Interest continues to grow regarding the role of serologic assays for the detection of prior infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The U.S. Food and Drug Administration (FDA) has granted emergency use authorization (EUA) status to many SARS-CoV-2 serologic assays. In this document, expert recommendations from clinical microbiologist members of the American Society for Microbiology (ASM) concerning detailed verification strategies for SARS-CoV-2 serologic assays with FDA EUA are provided, as are insights into assay limitations and reporting considerations for laboratories. Assessments concerning single-antibody and multiantibody isotype detection assays, which may provide either differentiated or nondifferentiated (i.e., total antibody) antibody class results, are addressed. Additional considerations prior to assay implementation are also discussed, including biosafety, quality control, and proficiency testing strategies. As the landscape of SARS-CoV-2 serologic testing is rapidly changing, this document provides updated guidance for laboratorians on application of these assays.
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http://dx.doi.org/10.1128/JCM.02148-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7771455PMC
December 2020

Comparison of Agar Dilution to Broth Microdilution for Testing Activity of Cefiderocol against Gram-Negative Bacilli.

J Clin Microbiol 2020 Dec 17;59(1). Epub 2020 Dec 17.

Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA

Cefiderocol (CFDC) is a siderophore cephalosporin with activity against Gram-negative bacterial species that are resistant to carbapenems and other drugs. The MICs of CFDC were determined for 610 Gram-negative bacilli, including 302 multinational isolates with characterized mechanisms of beta-lactam resistance, 180 clinical isolates from the Mayo Clinic and Mayo Clinic Laboratories not characterized for specific resistance mechanisms, and 128 isolates with CFDC MICs of ≥8 μg/ml obtained from International Health Management Associates, Inc. (IHMA, Schaumburg, IL). Broth microdilution using standard cation-adjusted Mueller-Hinton broth (BMD) and iron-depleted cation-adjusted Mueller-Hinton broth (ID-BMD), and agar dilution (AD) using standard Mueller-Hinton agar were performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. MICs were interpreted according to the investigational CLSI, FDA, and EUCAST breakpoints, and results were compared. MICs inhibiting 50 and 90% of organisms (MIC and MIC, respectively), essential agreement (EA), categorical agreement (CA), and error of different types were determined. Results showed considerable discordance between AD and ID-BMD. CFDC showed low EA and CA rates and high error rates for AD in comparison to ID-BMD. Overall, this study does not support use of standard AD for determining CFDC MICs.
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http://dx.doi.org/10.1128/JCM.00966-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7771473PMC
December 2020

Imipenem-Relebactam Susceptibility Testing of Gram-Negative Bacilli by Agar Dilution, Disk Diffusion, and Gradient Strip Methods Compared with Broth Microdilution.

J Clin Microbiol 2020 09 22;58(10). Epub 2020 Sep 22.

Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA

This study aimed to determine whether agar dilution, research-use-only disk diffusion (Mast Group Ltd., Bootle Merseyside, UK), Etest (bioMérieux, Inc., Durham, NC), and MIC test strip (MTS) (Liofilchem, Inc., Waltham, MA) methods yield equivalent results to those of broth microdilution (BMD) for imipenem-relebactam susceptibility testing using a collection of 297 Gram-negative bacilli, including members of the order and , enriched for drug resistance. MIC and disk diameter results were interpreted using United States Food and Drug Administration breakpoints. Overall, 76.8% of the isolates tested were susceptible to imipenem-relebactam by BMD. MIC values for agar dilution, Etest, and MTS were not significantly different from that for BMD, although they tended to be 1 to 2 dilutions higher. Essential agreement was 95.6% for agar dilution, 90.6% for Etest, and 85.2% for MTS. Categorical agreement was 98.0% for agar dilution, 73.1% for disk diffusion, 96.3% for Etest, and 96.6% for MTS. In conclusion, agar dilution and Etest yielded comparable results to BMD for imipenem-relebactam.
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http://dx.doi.org/10.1128/JCM.00695-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7512178PMC
September 2020

Clinical utility of anaerobic culture of cerebrospinal fluid.

Anaerobe 2020 Aug 25;64:102246. Epub 2020 Jul 25.

Department of Laboratory Medicine and Pathology Division of Clinical Microbiology Mayo Clinic, Rochester, MN, USA. Electronic address:

Anaerobic meningitis is a rare serious clinical condition which mainly affects vulnerable populations and patients with predisposing factors such as head trauma, prior neurosurgical procedures or implantable medical devices such as ventriculoperitoneal shunts or ventricular drains. In this study we retrieved data from aerobic and anaerobic cultures of cerebrospinal (CSF) or ventricular fluid ordered over a 5 year period at our institution. A total of 8868 aerobic and 594 anaerobic cultures were performed from 2013 to 2017. 24/594 (4%) anaerobic cultures from 14 patients were positive for anaerobes. Only 3 of those patients were diagnosed clinically with anaerobic meningitis, each with predisposing factors, while anaerobes (Cutibacterium acnes and Clostridium perfringens) recovered from the remaining 21 patients were regarded as contaminants. 129/8868 (1.45%) aerobic CSF cultures were positive for anaerobes. 120/129 (93%) cultures recovered C. acnes while non-C. acnes anaerobes were recovered in the remaining 9 cultures and were deemed to be contaminants. In the majority of situations, recovery of C. acnes from CSF or ventricular fluid was regarded as contamination. Our cohort included 18 patients with a ventriculoperitoneal shunt or ventricular drain, 17 of whom had C. acnes recovered from either aerobic or anaerobic culture, and 10 were treated with targeted antibiotics and surgical replacement of the shunt or drain. Anaerobic culture of the CSF or ventricular fluid aided in identification of two patients with anaerobic meningitis and an additional two patients with shunt infection. Anaerobe culture of CSF is important in identification of anaerobic meningitis, as growth of anaerobes other than C. acnes is rare from aerobic CSF culture.
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http://dx.doi.org/10.1016/j.anaerobe.2020.102246DOI Listing
August 2020

Staphylococcus aureus whole genome sequence-based susceptibility and resistance prediction using a clinically amenable workflow.

Diagn Microbiol Infect Dis 2020 Jul 11;97(3):115060. Epub 2020 Apr 11.

Division of Clinical Microbiology, Mayo Clinic, Rochester, MN; Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, MN. Electronic address:

We used graphical user interface-based automated analytical tools from Next Gen Diagnostics (Mountain View, CA) and 1928 Diagnostics (Gothenburg, Sweden) to analyze whole genome sequence (WGS) data from 102 unique blood culture isolates of Staphylococcus aureus to predict antimicrobial susceptibly, with results compared to those of phenotypic susceptibility testing. Of 916 isolate/antibiotic combinations analyzed using the Next Gen Diagnostics tool, there were 9 discrepancies between WGS predictions and phenotypic susceptibility/resistance, including 8 for clindamycin and 1 for minocycline. Of 612 isolate/antibiotic combinations analyzed using the 1928 Diagnostics tool, there were 13 discrepancies between WGS predictions and phenotypic susceptibility/resistance, including 9 for clindamycin, 3 for trimethoprim-sulfamethoxazole, and 1 for rifampin. Trimethoprim-sulfamethoxazole was not assessed by Next Gen Diagnostics, and minocycline was not assessed by 1928 Diagnostics. There was complete concordance between phenotypic susceptibility/resistance and genotypic prediction of susceptibility/resistance using both analytical platforms for oxacillin, vancomycin, and mupirocin, as well as by the Next Gen Diagnostics analytical tool for levofloxacin (the 1928 Diagnostics tool did not assess levofloxacin). These results suggest that, from a performance standpoint, with some caveats, automatic bioinformatics tools may be acceptable to predict susceptibility and resistance to a panel of antibiotics for S. aureus.
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http://dx.doi.org/10.1016/j.diagmicrobio.2020.115060DOI Listing
July 2020

Randomized trial evaluating clinical impact of RAPid IDentification and Susceptibility testing for Gram Negative bacteremia (RAPIDS-GN).

Clin Infect Dis 2020 May 7. Epub 2020 May 7.

Mayo Clinic, Rochester, MN.

Background: Rapid blood culture diagnostics are costly and of unclearbenefit for patients with Gram-negative bacilli (GNB) bloodstream infections (BSIs). We conducted a multicenter, prospective, randomized controlled trial comparing outcomes of patients with GNB BSI who had blood culture testing with standard of care (SOC) culture and antimicrobial susceptibility testing (AST) versus rapid organism identification (ID) and phenotypic AST using the Accelerate Pheno™ System (RAPID).

Methods: Patients with positive blood cultures with Gram stains showing GNB were randomized to SOC testing with antimicrobial stewardship review (AS) or RAPID with AS, at two medical centers between 10/2017-10/2018. The primary outcome was time to first antibiotic modification within 72 hours of randomization.

Results: Of 500 randomized subjects, 448 were included (226 SOC, 222 RAPID). Mean (S.D.) hours to results was faster for RAPID than SOC for organism ID [2.7 (1.2) vs 11.7 (10.5), p < 0.001] and AST [13.5 (56) vs. 44.9 (12.1), p<0.001]. Median (IQR) hours to first antibiotic modification was faster in the RAPID vs. SOC arm for overall antibiotics [8.6 (2.6, 27.6) vs. 14.9 (3.3, 41.1), difference 6.3, p=0.02] and Gram-negative antibiotics [17.3 (4.9, 72) vs. 42.1 (10.1, 72), difference 24.8, p<0.001]. Median (IQR) hours to antibiotic escalation was faster in the RAPID vs. SOC arm for antimicrobial-resistant BSIs [18.4 (5.8, 72) vs. 61.7 (30.4, 72), difference 43.3, p=0.01]. There were no statistically significant differences between the arms in patient outcomes including mortality and length of stay.

Conclusion: Rapid organism ID and phenotypic AST led to faster changes in antibiotic therapy for Gram-negative BSIs. (Funded by the U.S. NIH UM1AI104681; ClinicalTrials.gov number, NCT03218397.).
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http://dx.doi.org/10.1093/cid/ciaa528DOI Listing
May 2020

Breakthrough Bloodstream Infections Caused by Echinocandin-Resistant : An Emerging Threat to Immunocompromised Patients with Hematological Malignancies.

J Fungi (Basel) 2020 01 31;6(1). Epub 2020 Jan 31.

Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA.

Background: is a virulent fungal pathogen for which echinocandins are the primary therapy. Emergence of resistance to echinocandins of carries potentially ominous therapeutic implications.

Methods: We describe herein two patients with breakthrough fungemia during echinocandin therapy, characterize their molecular mechanism of resistance, and systematically review 13 previously reported cases of echinocandin-resistant bloodstream infections (BSIs) and other diseases.

Results: Among these 15 patients with echinocandin-resistant infections, the median age was 61 years (ages 28-84 years) and 13 (86%) were immunocompromised. Thirteen (86%) of all patients had a history of pervious or concurrent exposure to echinocandins. Isolates of from 11 cases, including the two index cases, underwent DNA sequencing of the gene for mutations known to confer echinocandin resistance. The amino acid substitution Ser654Pro was shown in four cases, while other mutations encoded Ser80S/Pro, Phe641Leu, Phe641Ser, Ser80S/Pro substitutions. These mutational events were not associated with collateral increases in minimum inhibitory concentrations to antifungal triazoles and amphotericin B. Overall mortality in patients with echinocandin-resistant infections was 40%. Among those six patients who died, two received monotherapy with voriconazole, one was treated with fluconazole, one remained on caspofungin, and two were switched to liposomal amphotericin B. Nine patients (60%) survived after being treated with an antifungal agent other than an echinocandin.

Conclusions: Emergence of resistance to echinocandins by occurs during antifungal therapy, is associated with high mortality, is mediated by a diverse range of mutations, retains in vitro susceptibility to triazoles and amphotericin B, and constitutes an emerging threat to patients with hematological malignancies.
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http://dx.doi.org/10.3390/jof6010020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7151208PMC
January 2020

Evaluation of the NG-Test MCR-1 Lateral Flow Assay and EDTA-Colistin Broth Disk Elution Methods To Detect Plasmid-Mediated Colistin Resistance among Gram-Negative Bacterial Isolates.

J Clin Microbiol 2020 03 25;58(4). Epub 2020 Mar 25.

Division of Medical Microbiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Plasmid-mediated colistin resistance (PMCR) is a global public health concern, given its ease of transmissibility. The purpose of this study was to evaluate two methods for the detection of PMCR from bacterial colonies: (i) the NG-Test MCR-1 lateral flow immunoassay (LFA; NG Biotech, Guipry, France) and (ii) the EDTA-colistin broth disk elution (EDTA-CBDE) screening test method. These methods were evaluated using a cohort of contemporary, clinical Gram-negative bacillus isolates from 3 U.S. academic medical centers (126 isolates of the , 50 isolates, and 50 species isolates; 1 isolate was positive) and 12 -positive CDC-FDA Antibiotic Resistance (AR) Isolate Bank isolates for which reference broth microdilution colistin susceptibility results were available. Eleven (4.6%) isolates were strongly positive by the MCR-1 LFA, with an additional 8 (3.4%) isolates yielding faintly positive results. The positive percent agreement (PPA) and negative percent agreement (NPA) for MCR-1 detection were 100% and 96.1%, respectively. Upon repeat testing, only a single false-positive MCR-2 producer remained, as the isolates with initially faintly positive results were negative. The EDTA-CBDE screening method had an overall PPA and NPA of 100% and 94.3%, respectively. The NPA for the EDTA-CBDE method was slightly lower at 94.2% with , whereas it was 96.0% with The MCR-1 LFA and EDTA-CBDE methods are both accurate and user-friendly methods for the detection of PMCR. Despite the rarity of PMCR among clinical isolates in the United States, these methods are valuable tools that may be implemented in public health and clinical microbiology laboratories to further discern the mechanism of resistance among colistin-resistant Gram-negative isolates and to detect PMCR for infection prevention and control purposes.
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http://dx.doi.org/10.1128/JCM.01823-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098752PMC
March 2020

A Case of () Infection With Multiple Life Stages Identified on Endoscopic Small Bowel Biopsies.

Int J Surg Pathol 2020 Dec 26;28(8):884-886. Epub 2020 Jan 26.

Mayo Clinic, Rochester, MN, USA.

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http://dx.doi.org/10.1177/1066896920901589DOI Listing
December 2020

Response to 'Comments on the published systematic review and meta-analysis on the increasing antibiotic resistance in Clostridioides difficile' by Kouhsari et al.

Anaerobe 2020 02 20;61:102148. Epub 2020 Jan 20.

Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, 55905, USA. Electronic address:

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http://dx.doi.org/10.1016/j.anaerobe.2020.102148DOI Listing
February 2020

A Laboratory's Guide to the Universe of Broad-Range Polymerase Chain Reactions.

Authors:
Audrey N Schuetz

Clin Infect Dis 2020 Sep;71(6):1558-1560

Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA.

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http://dx.doi.org/10.1093/cid/ciz1246DOI Listing
September 2020

Answer to January 2020 Photo Quiz.

J Clin Microbiol 2019 12 23;58(1). Epub 2019 Dec 23.

Department of Laboratory Medicine and Pathology, Division of Clinical Microbiology, Mayo Clinic, Rochester, Minnesota, USA

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http://dx.doi.org/10.1128/JCM.01612-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6935914PMC
December 2019

Photo Quiz: Rapidly Progressive Pneumonia in a Resident of the U.S. Midwest.

J Clin Microbiol 2019 12 23;58(1). Epub 2019 Dec 23.

Department of Laboratory Medicine and Pathology, Division of Clinical Microbiology, Mayo Clinic, Rochester, Minnesota, USA

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http://dx.doi.org/10.1128/JCM.01611-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6935918PMC
December 2019

Closing the Brief Case: Rat Bite Fever from a Kiss.

J Clin Microbiol 2019 12 23;58(1). Epub 2019 Dec 23.

Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA

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http://dx.doi.org/10.1128/JCM.00678-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6935919PMC
December 2019

The Brief Case: Rat Bite Fever from a Kiss.

J Clin Microbiol 2019 12 23;58(1). Epub 2019 Dec 23.

Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA

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http://dx.doi.org/10.1128/JCM.00677-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6935932PMC
December 2019

The Nesting Doll of Cutibacterium acnes Clonality.

Authors:
Audrey N Schuetz

J Clin Microbiol 2020 01 28;58(2). Epub 2020 Jan 28.

Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA

In this issue of the , R. E. Bumgarner, D. Harrison, and J. E. Hsu (J Clin Microbiol 58:e00121-19, 2020, https://doi.org/10.1128/JCM.00121-19) address in a retrospective analysis that clonality of isolates from deep tissue specimens obtained from patients during revision shoulder arthroplasty cannot be assumed. Given that multiple subtypes of isolates are present on and around the skin pilosebaceous follicles, the finding of multiple subtypes in deep tissues around a single patient's infected joint is not entirely surprising. However, the authors also challenge laboratorians to consider whether further assessment of isolates from the same joint should be performed and, if so, what testing should be undertaken.
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http://dx.doi.org/10.1128/JCM.01638-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6989077PMC
January 2020

Evaluation of Calcium-Enhanced Media for Colistin Susceptibility Testing by Gradient Agar Diffusion and Broth Microdilution.

J Clin Microbiol 2020 01 28;58(2). Epub 2020 Jan 28.

Accelerate Diagnostics, Tucson, Arizona, USA.

Despite the increasing reliance on polymyxin antibiotics (polymyxin B and colistin) for treatment of multidrug-resistant Gram-negative infections, many clinical laboratories are unable to perform susceptibility testing due to the lack of accurate and reliable methods. Although gradient agar diffusion is commonly performed for other antimicrobials, its use for polymyxins is discouraged due to poor performance characteristics. Performing gradient agar diffusion with calcium enhancement of susceptibility testing media has been shown to improve the identification of polymyxin-resistant isolates with plasmid-mediated resistance (). We therefore sought to evaluate the broad clinical applicability of this approach for colistin susceptibility testing by assessing a large and diverse collection of resistant and susceptible patient isolates collected from multiple U.S. medical centers. Among 217 isolates, the overall categorical and essential agreement for calcium-enhanced gradient agar diffusion were 73.7% and 65.5%, respectively, compared to the results for reference broth microdilution. Performance varied significantly by organism group, with agreement being highest for and lowest for Nevertheless, even for , there was a high rate of very major errors (9.2%). Performance was similarly poor for calcium-enhanced broth microdilution. While calcium enhancement did allow for more accurate categorization of -resistant isolates, there were unacceptably high rates of errors for both susceptible and non--resistant isolates, raising serious doubts about the suitability of these calcium-enhanced methods for routine colistin susceptibility testing in clinical laboratories.
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http://dx.doi.org/10.1128/JCM.01522-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6989058PMC
January 2020

Multicenter Study Demonstrates Standardization Requirements for Mold Identification by MALDI-TOF MS.

Front Microbiol 2019 20;10:2098. Epub 2019 Sep 20.

Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States.

Objectives: Rapid and accurate mold identification is critical for guiding therapy for mold infections. MALDI-TOF MS has been widely adopted for bacterial and yeast identification; however, few clinical laboratories have applied this technology for routine mold identification due to limited database availability and lack of standardized processes. Here, we evaluated the versatility of the NIH Mold Database in a multicenter evaluation.

Methods: The NIH Mold Database was evaluated by eight US academic centers using a solid media extraction method and a challenge set of 80 clinical mold isolates. Multiple instrument parameters important for spectra optimization were evaluated, leading to the development of two specialized acquisition programs (NIH method and the Alternate-B method).

Results: A wide range in performance (33-77%) was initially observed across the eight centers when routine spectral acquisition parameters were applied. Use of the NIH or the Alternate-B specialized acquisition programs, which are different than those used routinely for bacterial and yeast spectral acquisition (MBT_AutoX), in combination with optimized instrument maintenance, improved performance, illustrating that acquisition parameters may be one of the key limiting variable in achieving successful performance.

Conclusion: Successful mold identification using the NIH Database for MALDI-TOF MS on Biotyper systems was demonstrated across multiple institutions for the first time following identification of critical program parameters combined with instrument optimization. This significantly advances our potential to implement MALDI-TOF MS for mold identification across many institutions. Because instrument variability is inevitable, development of an instrument performance standard specific for mold spectral acquisition is suggested to improve reproducibility across instruments.
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http://dx.doi.org/10.3389/fmicb.2019.02098DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6764242PMC
September 2019

Multicenter Evaluation of Colistin Broth Disk Elution and Colistin Agar Test: a Report from the Clinical and Laboratory Standards Institute.

J Clin Microbiol 2019 11 23;57(11). Epub 2019 Oct 23.

Division of Medical Microbiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.

Susceptibility testing of the polymyxins (colistin and polymyxin B) is challenging for clinical laboratories. The Clinical and Laboratory Standards Institute (CLSI) Antimicrobial Susceptibility Testing Subcommittee evaluated two methods to enable accurate testing of these agents. These methods were a colistin broth disk elution (CBDE) and a colistin agar test (CAT), the latter of which was evaluated using two inoculum volumes, 1 μl (CAT-1) and 10 μl (CAT-10). The methods were evaluated using a collection of 270 isolates of , 122 isolates, and 106 spp. isolates. Overall, 94.4% of CBDE results were in essential agreement and 97.9% in categorical agreement (CA) with reference broth microdilution MICs. Nine very major errors (VME; 3.2%) and 3 major errors (ME; 0.9%) were observed. With the CBDE, 98.6% CA was observed for (2.5% VME, 0% ME), 99.3% CA was observed for (0% VME, 0.7% ME), and 93.1% CA was observed for spp. (5.6% VME, 3.3% ME). Overall, CA was 94.9% with 6.8% VME using CAT-1 and improved to 98.3% with 3.9% VME using CAT-10. No ME were observed using either CAT-1 or CAT-10. Using the CAT-1/CAT-10, the CA observed was 99.4%/99.7% for (1%/0.5% VME), 98.7%/100% for (8.3%/0% VME), and 88.5%/92.3% for spp. (21.4%/14.3% VME). Based on these data, the CLSI antimicrobial susceptibility testing (AST) subcommittee endorsed the CBDE and CAT-10 methods for colistin testing of and .
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http://dx.doi.org/10.1128/JCM.01269-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6813006PMC
November 2019

Increasing antibiotic resistance in Clostridioides difficile: A systematic review and meta-analysis.

Anaerobe 2019 Aug 19;58:35-46. Epub 2019 Jul 19.

Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, 55905, USA. Electronic address:

Background: Decreases in clinical response of Clostridioides difficile to antibiotics used for its treatment have raised concerns regarding antibiotic resistance. We conducted a systematic review and meta-analysis to study the resistance rates of C. difficile to various antibiotics over time.

Methods: We systematically searched MEDLINE, Embase, and Web of Science from inception through 03/31/2017 for observational studies assessing antibiotic resistance rates in C. difficile. Weighted summary estimates were calculated using inverse variance heterogeneity models [MetaXL software (v. 5.3)]. A priori subgroup analyses were done (by study year, continent, susceptibility testing method, origin of isolates); ribotype 027 strains were analyzed separately.

Results: From 1982 to 2017, 60 studies (8336 isolates) were analyzed. Fifty-three studies reported vancomycin resistance; weighted pooled resistance (WPR), 2.1% (95% CI, 0%-5.1%; I = 95%). Fifty-five studies reported metronidazole resistance; WPR, 1.9% (95% CI, 0.5%-3.6%; I = 89%). Compared to the period before 2012, vancomycin resistance increased by 3.6% (95% CI, 2.9%-4.2%; P < 0.001) after 2012, and metronidazole resistance decreased by 0.8% (95% CI, 0.1%-1.5%; P = 0.02). No isolates were resistant to fidaxomicin.

Conclusion: Resistance of C. difficile to vancomycin is increasing, with a smaller, declining resistance to metronidazole; there is significant heterogeneity between studies. Ongoing monitoring of resistance to commonly used antibiotics is required.
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http://dx.doi.org/10.1016/j.anaerobe.2019.102072DOI Listing
August 2019

Effect of Direct Electrical Current on Bones Infected with .

JBMR Plus 2019 May 31;3(5):e10119. Epub 2019 Jan 31.

Division of Clinical Microbiology Department of Laboratory Medicine and Pathology Mayo Clinic Rochester MN USA.

We are developing electrical approaches to treat biofilm-associated orthopedic foreign-body infection. Although we have previously shown that such approaches have antibiofilm activity, the effects on bone have not been assessed. Herein, low-amperage 200 μA fixed direct current (DC) was compared with no current, in a rat femoral foreign-body infection model. In the infected group, a platinum implant seeded with biofilm (10 CFU/cm), plus 50 μL of a 10 CFU suspension of bacteria, were placed in the femoral medullary cavity of 71 rats. One week later, rats were assigned to one of four groups: infected with no current or DC, or uninfected with no current or DC. After 2 weeks, bones were removed and subjected to histopathology, micro-computed tomography (μCT), and strength testing. Histopathology showed no inflammation or bony changes/remodeling in the uninfected no current group, and some osteoid formation in the DC group; bones from the infected no current group had evidence of inflammation without bony changes/remodeling; along with inflammation, there was moderate osteoid present in the DC group. μCT showed more cortical bone volume and density, trabecular thickness, and cancellous bone volume in the DC group compared with the no current group, for both uninfected and infected bones ( < 0.05). There was no difference in torsional strength or stiffness between the no current versus DC groups, for both infected and uninfected bones ( > 0.05). © 2018 The Authors. Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.
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http://dx.doi.org/10.1002/jbm4.10119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6524671PMC
May 2019

Factitial Panniculitis Associated With Cosmetic Filler.

Mayo Clin Proc 2019 05;94(5):914-915

Departments of Dermatology, and Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.

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http://dx.doi.org/10.1016/j.mayocp.2019.01.025DOI Listing
May 2019

Small intestinal microbial dysbiosis underlies symptoms associated with functional gastrointestinal disorders.

Nat Commun 2019 05 1;10(1):2012. Epub 2019 May 1.

Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, 55902, USA.

Small intestinal bacterial overgrowth (SIBO) has been implicated in symptoms associated with functional gastrointestinal disorders (FGIDs), though mechanisms remain poorly defined and treatment involves non-specific antibiotics. Here we show that SIBO based on duodenal aspirate culture reflects an overgrowth of anaerobes, does not correspond with patient symptoms, and may be a result of dietary preferences. Small intestinal microbial composition, on the other hand, is significantly altered in symptomatic patients and does not correspond with aspirate culture results. In a pilot interventional study we found that switching from a high fiber diet to a low fiber, high simple sugar diet triggered FGID-related symptoms and decreased small intestinal microbial diversity while increasing small intestinal permeability. Our findings demonstrate that characterizing small intestinal microbiomes in patients with gastrointestinal symptoms may allow a more targeted antibacterial or a diet-based approach to treatment.
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http://dx.doi.org/10.1038/s41467-019-09964-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6494866PMC
May 2019