Carey-Ann D Burnham

Washington University in St. Louis, San Luis, Missouri, United States

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Publications (86)394.31 Total impact

  • Emerging infectious diseases 06/2015; 21(6). DOI:10.3201/eid2106.141504 · 7.33 Impact Factor
  • Craig B Wilen, Allison R McMullen, Carey-Ann D Burnham
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    ABSTRACT: When mycobacteria are recovered in clinical specimens, timely species-level identification is required to establish the clinical significance of the isolate and facilitate optimization of antimicrobial therapy. Matrix assisted laser desorption-time of flight mass spectrometry (MALDI-TOF MS) has recently been reported to be a reliable and expedited method for identification of mycobacteria, although variable specimen preparation techniques and databases for analysis are reported across studies. Here we compared two MALDI-TOF MS instrumentation platforms and three databases: Bruker Biotyper Real Time Classification 3.1 (Biotyper), VITEK MS Plus Saramis Premium (Saramis), and VITEK MS v3.0. We evaluated two sample preparation techniques and demonstrate that extraction methods are not interchangeable across different platforms or databases. Once testing parameters were established, a panel of 157 mycobacteria isolates (including 16 Mycobacterium tuberculosis isolates) was evaluated, demonstrating that with the appropriate specimen preparation, all three methods provide reliable identification for most species. Using a score cutoff of ≥ 1.8, the Biotyper correctly identified 133 (84.7%) isolates with no misidentifications. Using a confidence value of ≥ 90%, Saramis correctly identified 134 (85.4%) isolates with one misidentification and VITEK MS v3.0 correctly identified 140 (89.2%) isolates with one misidentification. The accuracy was not significantly different across the three platforms (p=0.14). In addition we show that VITEK MS v3.0 requires modestly fewer repeat analyses compared to the Biotyper and Saramis methods (p=0.04) which may have implications for laboratory workflow. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
    Journal of clinical microbiology 05/2015; DOI:10.1128/JCM.00567-15 · 4.23 Impact Factor
  • The Journal of Infectious Diseases 05/2015; DOI:10.1093/infdis/jiv278 · 5.78 Impact Factor
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    ABSTRACT: Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has revolutionized the identification of clinical bacterial and yeast isolates. However, data describing the reproducibility of MALDI-TOF MS for microbial identification are scarce. In this study, we show that MALDI-TOF MS-based microbial identification is highly reproducible and can tolerate numerous variables, including differences in testing environments, instruments, operators, reagent lots, and sample positioning patterns. Finally, we reveal that samples of bacterial and yeast isolates prepared for MALDI-TOF MS identification can be repeatedly analyzed without compromising organism identification. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
    Journal of clinical microbiology 04/2015; DOI:10.1128/JCM.00187-15 · 4.23 Impact Factor
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    ABSTRACT: We report two cases of bacteremia with Actinobaculum schaalii, a rarely reported, anaerobic, Gram-positive bacterium. The first case was a patient with renal cancer who developed pyelonephritis after cryoablation, and the second was a patient who developed sepsis after a urogenital procedure. Bacteremia resolved after administration of empiric antibiotic therapy. Copyright © 2015. Published by Elsevier Ltd.
    Anaerobe 04/2015; 34. DOI:10.1016/j.anaerobe.2015.04.006 · 2.36 Impact Factor
  • Morgan A. Pence, Carey-Ann D. Burnham
    04/2015; DOI:10.1016/j.jgar.2015.03.004
  • Mark D. Gonzalez, Craig B. Wilen, Carey-Ann D. Burnham
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    ABSTRACT: Infections with chlorophyllic algae are uncommon. Invasive infection with Desmodesmus armatus developed in two patients independently after they each sustained a penetrating freshwater injury.
    New England Journal of Medicine 03/2015; 372(10):982-4. DOI:10.1056/NEJMc1401816 · 54.42 Impact Factor
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    ABSTRACT: The proliferation of genetically modified mouse models has exposed phenotypic variation between investigators and institutions that has been challenging to control1, 2, 3, 4, 5. In many cases, the microbiota is the presumed cause of the variation. Current solutions to account for phenotypic variability include littermate and maternal controls or defined microbial consortia in gnotobiotic mice6, 7. In conventionally raised mice, the microbiome is transmitted from the dam2, 8, 9. Here we show that microbially driven dichotomous faecal immunoglobulin-A (IgA) levels in wild-type mice within the same facility mimic the effects of chromosomal mutations. We observe in multiple facilities that vertically transmissible bacteria in IgA-low mice dominantly lower faecal IgA levels in IgA-high mice after co-housing or faecal transplantation. In response to injury, IgA-low mice show increased damage that is transferable by faecal transplantation and driven by faecal IgA differences. We find that bacteria from IgA-low mice degrade the secretory component of secretory IgA as well as IgA itself. These data indicate that phenotypic comparisons between mice must take into account the non-chromosomal hereditary variation between different breeders. We propose faecal IgA as one marker of microbial variability and conclude that co-housing and/or faecal transplantation enables analysis of progeny from different dams.
    Nature 02/2015; 521(7550). DOI:10.1038/nature14139 · 42.35 Impact Factor
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    ABSTRACT: We evaluated a variety of methods to recover S. aureus from inanimate surfaces. Two contact agar plates and three swab sampling methods were tested on porous and non-porous surfaces and bar soap. The cost and ease of use of each method was also evaluated. S. aureus was recovered using all methods on both porous and non-porous surfaces. S. aureus could not be detected on three of four brands of soap.
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    ABSTRACT: Excessive utilization of laboratory diagnostics leads to increased healthcare costs. We evaluated criteria to reduce unnecessary nucleic acid amplification testing (NAAT) for viral pathogens in the cerebrospinal fluid (CSF) of adults. This is a single-center split retrospective observational study with a screening cohort from 2008-2012 and validation cohort from 2013. Adults with an available result for herpes simplex virus (HSV-1/2), varicella-zoster virus (VZV), cytomegalovirus (CMV), or enterovirus (EV) NAAT in the CSF between 2008 and 2013 were included (n=10,917). During this study, 1.3% (n=140) of viral NAAT studies were positive. Acceptance criteria of >10 nucleated cells/μl in the CSF of immunocompetent subjects would have reduced HSV-1/2, VZV, CMV, and EV testing by 63%, 50%, 44%, and 51% respectively, from 2008-2012. When these criteria were applied to the 2013 validation data set, 54% of HSV-1/2, 57% of VZV, 35% of CMV, and 56% of EV tests would have been cancelled. No clinically significant positive tests would have been cancelled in 2013 with this approach. The introduction of a computerized order entry set was associated with increased test requests, suggesting computerized order sets may contribute to unnecessary testing. Acceptance criteria of >10 nucleated cells/μl in the CSF of immunocompetent adults for viral CSF NAAT tests would increase clinical specificity and preserve sensitivity, resulting in significant cost savings. Implementation of these acceptance criteria led to a 46% reduction in testing over a limited follow-up period. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
    Journal of Clinical Microbiology 01/2015; 53(3). DOI:10.1128/JCM.03161-14 · 4.23 Impact Factor
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    ABSTRACT: Bloodstream infection with Staphylococcus aureus, including methicillin resistant S. aureus (MRSA), is a serious condition that carries a high mortality rate and is also associated with significant hospital costs. Rapid and accurate identification and differentiation of methicillin susceptible (MSSA) and resistant S. aureus directly from positive blood cultures has demonstrated benefit to both patient outcome and cost of care metrics. We compare the next generation Xpert MRSA/SA BC assay (Xpert) to the GeneOhm StaphSR assay (GeneOhm) for the identification and detection of S. aureus and methicillin resistance in prospectively collected blood culture broths containing Gram-positive cocci. All results were compared to routine bacterial culture as the gold standard. Across 8 collection and test sites, Xpert demonstrated a sensitivity of 99.6% (range 96.4%-100%) and specificity of 99.5% (range 98.0%-100%) for identification of S. aureus, and a sensitivity of 98.1% (range 87.5%-100%) and specificity of 99.6% (range 98.3%-100%) for identification of MRSA. In comparison, GeneOhm demonstrated a sensitivity of 99.2% (range 95.2%-100%) and specificity of 96.5% (range 89.2%-100%) for identification of S. aureus, and a sensitivity of 94.3% (range 87.5%-100%) and specificity of 97.8% (range 96.1%-100%) for identification of MRSA. Five of six cultures falsely reported as negative for MRSA by GeneOhm were correctly identified as positive by Xpert, while one culture falsely reported as negative for MRSA by Xpert was correctly reported as positive by GeneOhm. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
    Journal of Clinical Microbiology 12/2014; 53(3). DOI:10.1128/JCM.03108-14 · 4.23 Impact Factor
  • Morgan A Pence, Tiffany Hink, Carey-Ann D Burnham
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    ABSTRACT: We evaluated the performance characteristics of chromID CARBA and HardyCHROM Carbapenemase for detection of carbapenemase-producing Enterobacteriaceae (CPE). A CPE prevalence study was conducted using chromID CARBA; this demonstrated that in low prevalence settings, CPE screening agars may lack specificity and confirmation of putative isolates is necessary. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
    Journal of Clinical Microbiology 11/2014; 53(2). DOI:10.1128/JCM.03208-14 · 4.23 Impact Factor
  • Morgan A Pence, Carey-Ann D Burnham
    Journal of Clinical Microbiology 11/2014; 52(11):4121. DOI:10.1128/JCM.00854-13 · 4.23 Impact Factor
  • Morgan A Pence, Carey-Ann D Burnham
    Journal of Clinical Microbiology 11/2014; 52(11):3835. DOI:10.1128/JCM.00853-13 · 4.23 Impact Factor
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    ABSTRACT: Background: Clostridium difficile (C. difficile), vancomycin resistant Enterococcus (VRE) and methicillin resistant Staphylococcus aureus (MRSA) are multidrug resistant organisms (MDRO) and cause healthcare associated infections. Previous studies have demonstrated that these MDROs can be recovered from a variety of foods including meat and vegetables. The objective of this study was to determine if C. difficile, VRE and MRSA is present in the food of hospitalized patients. Methods: Patients admitted from May 9, 2011 to July 12, 2012 at Barnes-Jewish Hospital with no diarrhea were approached to participate. Stool/rectal swab specimens were collected on admission, weekly and discharge and cultured for C. difficile. Study subjects placed samples of food from each meal into provided sterile specimen cups. Following homogenization, all food was cultured for C. difficile. A random sampling of food was cultured for VRE and MRSA. Molecular typing was performed. Medical charts were reviewed to look for positive clinical cultures for the organism during the enrollment period. Results: 148 patients were enrolled and 910 food specimens were collected and cultured for C. difficile. 218 food specimens from 122 patients were cultured for VRE and MRSA. Two (0.2%) food samples were positive for C. difficile, two (0.9%) were positive for VRE and two (0.9%) were positive for MRSA. Types of food present based on organism were: C. difficile – vegetables, grains, and other; VRE – dairy, grain and other; MRSA – poultry, fruit, vegetable, grain, and other. The C. difficile strains typed as ribotype 001 and 027. Both MRSA strains were SCCmec type IV. None of the patients with food positive for C. difficile were colonized with C. difficile before or after the positive food specimen. None of the patients with food positive for MRSA had MRSA in a clinical culture during the admission. One patient with food positive for VRE had a positive clinical culture for VRE (VRE surveillance stool culture) 32 days after the positive food specimen. Conclusion: Recovery of MRDOs from hospital food specimens was rare. One patient with VRE recovered from food was found to have a positive VRE surveillance stool culture. Hospital food appears to be an uncommon source for acquisition of these MDROs.
    IDWeek 2014 Meeting of the Infectious Diseases Society of America; 10/2014
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    ABSTRACT: Background: Negative routine cultures often occur with prosthetic joint infections (PJI) despite overt signs of infection. 16s rRNA gene polymerase chain reaction (PCR) has been proposed as a diagnostic tool to help identify causative organisms among those with culture negative PJI. Methods: Joint fluid, tissue or bone was collected from patients with PJI who were admitted to Barnes-Jewish Hospital between 9/15/2012 and 4/15/2013. PJI was defined per IDSA guidelines. Patients were considered to be culture negative or positive based on the results of routine microbiological cultures after 48 hours of incubation. DNA was extracted from samples using the MoBio Bacteremia Kit. Full length amplification of the 16S rRNA gene was performed, and PCR products were visualized using agarose gel electrophoresis. If a PCR product was present, it was sequenced and compared to GenBank and RDP to assign an organism identification per CLSI standards. Control samples were performed with each run. Results: We collected 54 samples from 42 unique patients with culture-negative PJI including 28 (51.9%) hip, 18 (33.3%) knee, 7 (13.0%) shoulder, and 1 (1.9%) ankle samples. Sample types included tissue (31, 57.4%), fluid (13, 24.1%), and bone (10, 18.5%). Staphylococcus aureus-specific PCR was negative in all patients with culture negative PJI. 16s rRNA gene PCR was also negative in all patients with culture negative PJI. Samples were collected from 35 patients with culture positive PJI including 18 (51.4%) hip and 17 (48.6%) knee samples. Sample types included 25 (71.4%) tissue, 8 (22.9%) fluid, and 2 (5.7%) bone. S. aureus was isolated in 21 routine cultures. S. aureus-specific PCR correctly identified 12 (57.1%) of samples with S. aureus and incorrectly identified 1 sample. 16s rRNA gene PCR correctly identified 3 samples with S. aureus and 2 samples with Streptococcus spp. Two polymicrobial cultures were identified as mixed; 4 monomicrobial cultures were identified as mixed. Among those with positive cultures for S. aureus, PCR was more likely to be positive from tissue samples than all other tissue types (p=.03). Conclusion: 16s rRNA gene PCR proved to be unreliable diagnostic tool among patients with culture positive or negative PJI. Conclusion: 16s rRNA gene PCR proved to be an unreliable diagnostic tool for patients with culture positive and negative PJI.
    IDWeek 2014 Meeting of the Infectious Diseases Society of America; 10/2014
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    ABSTRACT: Background: Rifampin is widely utilized in treatment of prosthetic joint infections (PJI) with retained hardware caused by Staphylococcal species. However, there is little data regarding clinical outcomes. Methods: We conducted a retrospective cohort study of patients with coagulase-negative Staphylococcus (CoNS), methicillin-sensitive (MSSA), and -resistant Staphylococcus aureus(MRSA) PJI who were treated with adjunctive rifampin therapy after admission to a large tertiary care hospital from July 2005 to June 2010. The epidemiology, clinical outcomes, and risk factors for failure were examined. Treatment success was defined as no further readmissions for PJI within 1 year of the index hospitalization. Results: A total of 237 patients with MRSA (56), MSSA (69), or CoNS (112) PJI were identified during the study period. Sixty-eight patients (29%) were discharged with rifampin combination therapy. Amongst patients treated with rifampin, MSSA was isolated in 30% and MRSA isolated in 25%. Partial exchange and debridement and implant retention (DAIR) was completed in 63% of all patients. Vancomycin was the most commonly prescribed IV antibiotic (48, 71%), followed by oxacillin (9, 13%). Concurrent therapy with daptomycin (2, 2.9%) or ceftriaxone (4, 5.9%) was rarely used. Antibiotic duration averaged 51 days (range 30-106, ± 14.6). Abnormal laboratories were common (53, 78%); however, only 18 (26.5%) required a change in antibiotic therapy. The most common side effect necessitating change was rash (9, 13.2%). Significant drug-drug interactions (1) and liver toxicity (2) were rare. Three patients (4%) were lost to follow up. Complications of antibiotic use caused 9% of all readmissions and 25% of the cohort was readmitted for infection (16, 25%). Rifampin use was not associated with decreased readmission for infection (MSSA, p=0.4; MRSA p=0.5; CoNS, p=0.7). Conclusion: Rifampin has been utilized as adjunctive treatment of staphylococcal PJI in cases of retained hardware. Although well tolerated in the study population, rifampin did not reduce the risk for PJI-related readmission compared to those who did not receive rifampin.
    IDWeek 2014 Meeting of the Infectious Diseases Society of America; 10/2014
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    ABSTRACT: Background: Methicillin-resistant Staphylococcus aureus (MRSA) infection is an important cause of ventilator-associated pneumonia. As a result, empiric therapy often includes anti-staphylococcal agents. Our objective was to evaluate the GeneXpert MRSA/SA SSTI Assay (Cepheid, Sunnyvale, CA) for use in lower respiratory tract (LRT) specimens for rapid MRSA detection as a tool in antimicrobial stewardship efforts. Methods: For the validation of the assay, we included laboratory-derived (“spiked”) bronchoalveolar lavage (BAL) specimens with known quantities of MRSA (SCCmec II and IV; 102 - 105 CFU/mL) and 30 banked LRT samples. For the clinical phase, we determined if LRT samples submitted to the microbiology lab met criteria for suspected pneumonia and were collected from ventilated patients. Comparator standard-of care culture results and antibiotic utilization information were collected. Antibiotic days for vancomycin and linezolid were calculated. Results: The limit of detection for MRSA in the spiked BAL samples was 103 CFU/ml. The assay correctly detected MRSA in 9/9 frozen samples and excluded MRSA in 21/21 samples with other organisms (sensitivity 100%, specificity 100%). We screened 310 LRT specimens; 100 met study criteria. Ten samples tested positive for MRSA with rapid PCR, while 6 were positive in routine cultures. Rapid PCR correctly detected 5/6 positive and 89/94 negative MRSA specimens for a sensitivity of 83.3% (95% CI: 36.1-97.2%) and specificity of 94.7% (95% CI: 88-98.2%) with a negative predictive value of 98.9% (95% CI: 93.9-99.8%). A total of 748 vancomycin and 305 linezolid antibiotic days were associated with the enrolled specimens. Vancomycin and linezolid utilization would decrease by 68.4% and 83%, respectively, if they were discontinued 1 day after negative rapid PCR results. Conclusion: A rapid MRSA PCR test performed well against the gold standard in respiratory samples from ventilated patients with suspected pneumonia. Its implementation has the potential of reducing empiric vancomycin and linezolid utilization.
    IDWeek 2014 Meeting of the Infectious Diseases Society of America; 10/2014
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    ABSTRACT: Clostridium difficile infections (CDI) are a growing concern in North America, because of their increasing incidence and severity. Using integrated approaches, we correlated pathogen genotypes and host clinical characteristics for 46 C. difficile infections in a tertiary care medical center, during a six-month interval from January to June 2010. Multi-locus sequence typing (MLST) demonstrated 21 known and two novel sequence types (STs), suggesting that the institution's C. difficile strains are genetically diverse. ST1 (which corresponds to pulsed-field gel electrophoresis strain type NAP1/ribotype 027), was the most prevalent (32.6%), 43.5% of the isolates were binary toxin gene positive, of which 75% were ST1. All strains were ciprofloxacin resistant and metronidazole susceptible, and 8.3% and 13.0% of the isolates were resistant to clindamycin and tetracycline, respectively. The corresponding resistance loci, including potential novel mutations, were identified from the whole genome sequencing (WGS) of the resistant strains. Core genome SNPs determining the phylogenetic relatedness of the 46 strains recapitulated MLST types, and provided greater inter-strain differentiation. Disease severity was greatest in patients infected with ST-1 and/or binary gene positive strains, but genome-wide SNP analysis failed to provide additional associations with CDI severity within the same STs. We conclude MLST and core genome SNP typing result in the same phylogenetic grouping of the 46 C. difficile strains collected in a single hospital. WGS also has the capacity to differentiate those strains within STs, and allows the strains comparison at individual gene level and at whole genome level.
    Journal of Clinical Microbiology 10/2014; DOI:10.1128/JCM.02115-14 · 4.23 Impact Factor

Publication Stats

479 Citations
394.31 Total Impact Points


  • 2010–2015
    • Washington University in St. Louis
      • • Department of Pathology and Immunology
      • • Department of Pediatrics
      San Luis, Missouri, United States
  • 2005–2011
    • University of Alberta
      • Department of Laboratory Medicine and Pathology
      Edmonton, Alberta, Canada