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Papers by Tracie Lloyd

Research paper thumbnail of Evaluation of the OSOM Trichomonas Rapid Test versus Wet Preparation Examination for Detection of Trichomonas vaginalis Vaginitis in Specimens from Women with a Low Prevalence of Infection

Journal of Clinical Microbiology, 2008

The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP)... more The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP) for the detection of Trichomonas vaginalis vaginitis in women with a low prevalence of infection. A total of 19/1,009 (2%) women had T. vaginalis infection. OSOM Trich had very good performance, with sensitivity, specificity, efficiency, positive predictive value, and negative predictive value of 94.7, 100, 99.9, 100, and 99.9%, respectively. The implementation of OSOM Trich would decrease labor costs.

Research paper thumbnail of Molecular diagnosis of vaginitis: comparing qPCR and microbiome profiling approaches to current microscopy scoring

Journal of Clinical Microbiology

INTRODUCTION: Vaginitis is often diagnosed by microscopy and limited to testing for bacterial vag... more INTRODUCTION: Vaginitis is often diagnosed by microscopy and limited to testing for bacterial vaginosis (BV), vulvovaginal candidiasis and trichomoniasis. Approximately 10% of vaginal swabs are negative, but designated ‘altered flora' by BV Nugent score, leaving clinicians unsure how to treat patients. Accurate and comprehensive vaginitis diagnostics are needed to direct treatment and reduce risks of recurrent or more severe infections. METHOD: Vaginal swabs were collected from 93 women (mean age: 23.53 yrs, range: 18 – 42 yrs) in a cross-sectional study. Microscopy results for BV and Candida were compared to two molecular approaches, (a) comprehensive qPCR assay including aerobic vaginitis (AV), Candida, STI and BV (Applied Biosystems) with an accompanying BV interpretive algorithm (Coriell Life Sciences) and (b) microbiome profiling of the 16S rRNA gene (Illumina). RESULTS: Microscopy + BV Nugent score had 76% overall agreement with the qPCR + BV interpretive algorithm method ...

Research paper thumbnail of Evaluation of Simplexa Group A Strep Direct Kit Compared to Hologic Group A Streptococcal Direct Assay for Detection of Group A Streptococcus in Throat Swabs

Journal of clinical microbiology, 2018

Diagnosis of bacterial pharyngitis is confirmed by detection of group A (GAS) in patient throat s... more Diagnosis of bacterial pharyngitis is confirmed by detection of group A (GAS) in patient throat samples. Testing of throat samples has historically relied on culture, but new molecular methods allow much faster test turnaround time (i.e., same day versus 48 to 72 h for culture). Our laboratory uses the Hologic GAS Direct (GASD) assay for screening more than 125,000 throat samples per year. Simplexa GAS Direct is a new real-time quantitative PCR (qPCR) assay that does not require initial DNA extraction. Performance of Simplexa qPCR was compared to GASD. A total of 289 throat swabs were collected from patients attending ambulatory clinics in Calgary, Alberta, Canada. A total of 60 (20.8%) of the samples were initially GAS positive by either method: 54 by both methods, 4 by Simplex qPCR alone, and 2 by GASD alone. An in-house PCR using a unique GAS primer set was used to resolve the 6 discrepant results. Overall, GASD compared to Simplexa qPCR had a sensitivity, specificity, positive p...

Research paper thumbnail of Evaluation of StrepB Select Chromagar and the Fast Track Diagnostics Group B Streptococcus (GBS) real-time polymerase chain reaction assay compared to routine culture for detection of GBS during antepartum screening

Journal of clinical microbiology, Jul 26, 2017

Life-threatening infection in neonates due to Group B Streptococcus (GBS) is preventable by scree... more Life-threatening infection in neonates due to Group B Streptococcus (GBS) is preventable by screening near-term pregnant women and treatment at delivery. 295 vaginal-rectal swabs were collected from women attending antepartum clinics in Calgary. GBS colonization was detected by the standard culture method (Strep B Carrot broth subbed to blood agar with a neomycin disk), and compared to recovery using Strep Group B Broth (Dalynn Biologicals) subbed to StrepB Select chromagar (CA) (Bio-Rad Laboratories), and the Fast Track Diagnostics GBS real-time PCR (qPCR) assay (Phoenix Airmid Biomedical Corp.) performed on broth-enriched samples using the Abbott m2000sp/m2000rt system. A total of 62/295 (21%) women were colonized with GBS; 58(19.7%) cases were detected by standard culture while CA and qPCR each found 61 (20.7%) cases. The qPCR vs. CA had similar performance with sensitivity, specificity, PPV and NPV of 98.4% vs. 98.4%, 99.6% vs. 99.6%%, 98.4% vs. 98.4% and 99.6% vs. 99.6% respect...

Research paper thumbnail of Beyond B: HIV-1 viral load multi-assay comparison in a cohort of Canadian patients with diverse HIV subtype infections

Research paper thumbnail of Clinical and economic evaluation of BBL™ CHROMagar™ Salmonella (CHROMSal) versus subculture after selenite broth enrichment to CHROMSal and Hektoen enteric agars to detect enteric Salmonella in a large regional microbiology laboratory

Diagnostic Microbiology and Infectious Disease, Sep 30, 2010

Stool culture for enteric pathogens is one of the most labor-intensive clinical microbiology proc... more Stool culture for enteric pathogens is one of the most labor-intensive clinical microbiology procedures. Direct plating of stool to BBL™ CHROMagar™ Salmonella (CHROMSal) (BD Diagnostics, Sparks, MD) versus subculture after selenite broth enrichment (Sel) to CHROMSal (Sel-CHROMSal) and Hektoen enteric agar (Sel-Hek) (PML Microbiologicals, Eugene, OR) to detect Salmonella were compared. The number of colony picks and biochemical/serotyping tests per plate was recorded. A cost comparison was done. Fifty-one of 2999 (1.7%) stools yielded Salmonella sp., and 80% of isolates grew on CHROMSal by 24 h. CHROMSal demonstrated much less falsepositive growth compared to Sel-Hek (P b 0.0001), which reduced biochemical and serotyping tests by 85% and 20%, respectively. Sel-CHROMSal and CHROMSal versus Sel-Hek improved enteric Salmonella detection when compared to a true positive "gold standard" (i.e., recovery by any culture method) with a sensitivity, specificity, positive predictive value, and negative predictive value of 100% and 94.12%, 100% and 99.97%, 100% and 97.96%, and 100% and 99.90%, respectively. CHROMSal use would result in substantial cost and labor savings.

Research paper thumbnail of HIV-1 viral load multi-assay comparison of the RealTime HIV-1, COBAS TaqMan 48 v 1.0, Easy Q v1. 2 and Versant v3. 0 assays in a cohort of Canadian patients with …

Journal of Clinical …, 2010

... RealTime HIV-1, COBAS 3 TaqMan 48 v 1.0, Easy Q v1.2 and Versant v3.0 assays in a Cohort of C... more ... RealTime HIV-1, COBAS 3 TaqMan 48 v 1.0, Easy Q v1.2 and Versant v3.0 assays in a Cohort of Canadian 4 Patients with Diverse HIV Subtype Infections 5 6 Church, Deirdre1,3,4* , Gregson, Daniel1,3,4 , Tracie Lloyd1, Marina Klein5, Brenda 7 Beckthold2, Kevin Laupland1,4 ...

Research paper thumbnail of Utility of Gram Stain for the Microbiological Analysis of Burn Wound Surfaces

Surface swab cultures have attracted attention as a potential alternative to biopsy histology or ... more Surface swab cultures have attracted attention as a potential alternative to biopsy histology or quantitative culture methods for microbiological burn wound monitoring. To our knowledge, the utility of adding a Gram-stained slide in this context has not been evaluated previously. To determine the degree of correlation of Gram stain with culture for the microbiological analysis of burn wound surfaces. Prospective laboratory analysis. Urban health region/centralized diagnostic microbiology laboratory. Burn patients hospitalized in any Calgary Health Region burn center from November 2000 to September 2001. Gram stain plus culture of burn wound surface swab specimens obtained during routine dressing changes or based on clinical signs of infection. Degree of correlation (complete, high, partial, none), including weighted kappa statistic (kappa(w)), of Gram stain with culture based on quantitative microscopy and degree of culture growth. A total of 375 specimens from 50 burn patients were evaluated. Of these, 239 were negative by culture and Gram stain, 7 were positive by Gram stain only, 89 were positive by culture only, and 40 were positive by both methods. The degree of complete, high, partial, and no correlation of Gram stain with culture was 70.9% (266/375), 1.1% (4/375), 2.4% (9/375), and 25.6% (96/375), respectively. The degree of correlation for all 375 specimens, as expressed by the weighted kappa statistic, was found to be fair (kappa(w) = 0.32).Conclusion.-The Gram stain is not suitable for the microbiological analysis of burn wound surfaces.

Research paper thumbnail of Evaluation of StrepB Carrot Broth versus Lim Broth for Detection of Group B Streptococcus Colonization Status of Near-Term Pregnant Women

Journal of Clinical Microbiology, 2008

The performance of StrepB Carrot Broth (SCB) versus group B Lim broth (LIM) for detection of grou... more The performance of StrepB Carrot Broth (SCB) versus group B Lim broth (LIM) for detection of group B streptococcus (GBS) colonization status in near-term pregnant women (35 to 37 weeks of gestation) was evaluated. Dually collected vaginal/rectal swabs from 279 women enrolled from a single large maternity clinic were analyzed. Fifty (18%) women were colonized by GBS according to both methods. SCB had excellent diagnostic performance compared to LIM, with sensitivity, specificity, positive predictive value, and negative predictive value of 92%, 100%, 100%, and 98.3%, respectively. Improved diagnostic efficiency due to direct reporting of GBS cases based on an orange color change in the SCB decreased overall labor and material costs.

Research paper thumbnail of Evaluation of the OSOM Trichomonas Rapid Test versus Wet Preparation Examination for Detection of Trichomonas vaginalis Vaginitis in Specimens from Women with a Low Prevalence of Infection

Journal of Clinical Microbiology, 2008

The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP)... more The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP) for the detection of Trichomonas vaginalis vaginitis in women with a low prevalence of infection. A total of 19/1,009 (2%) women had T. vaginalis infection. OSOM Trich had very good performance, with sensitivity, specificity, efficiency, positive predictive value, and negative predictive value of 94.7, 100, 99.9, 100, and 99.9%, respectively. The implementation of OSOM Trich would decrease labor costs.

Research paper thumbnail of Utility of Gram Stain for the Microbiological Analysis of Burn Wound Surfaces

Archives of pathology & laboratory medicine

Surface swab cultures have attracted attention as a potential alternative to biopsy histology or ... more Surface swab cultures have attracted attention as a potential alternative to biopsy histology or quantitative culture methods for microbiological burn wound monitoring. To our knowledge, the utility of adding a Gram-stained slide in this context has not been evaluated previously. To determine the degree of correlation of Gram stain with culture for the microbiological analysis of burn wound surfaces. Prospective laboratory analysis. Urban health region/centralized diagnostic microbiology laboratory. Burn patients hospitalized in any Calgary Health Region burn center from November 2000 to September 2001. Gram stain plus culture of burn wound surface swab specimens obtained during routine dressing changes or based on clinical signs of infection. Degree of correlation (complete, high, partial, none), including weighted kappa statistic (kappa(w)), of Gram stain with culture based on quantitative microscopy and degree of culture growth. A total of 375 specimens from 50 burn patients were evaluated. Of these, 239 were negative by culture and Gram stain, 7 were positive by Gram stain only, 89 were positive by culture only, and 40 were positive by both methods. The degree of complete, high, partial, and no correlation of Gram stain with culture was 70.9% (266/375), 1.1% (4/375), 2.4% (9/375), and 25.6% (96/375), respectively. The degree of correlation for all 375 specimens, as expressed by the weighted kappa statistic, was found to be fair (kappa(w) = 0.32).Conclusion.-The Gram stain is not suitable for the microbiological analysis of burn wound surfaces.

Research paper thumbnail of Antimicrobial susceptibility and combination testing of invasive Stenotrophomonas maltophilia isolates

Scandinavian Journal of Infectious Diseases, 2013

Treatment of invasive Stenotrophomonas maltophilia infections is difficult due to this organism&a... more Treatment of invasive Stenotrophomonas maltophilia infections is difficult due to this organism's inherent multidrug resistance and increasing resistance to trimethoprim-sulfamethoxazole via acquisition of the sul genes. In vitro antibiotic susceptibility testing was performed using a customized broth microdilution panel. Combination testing for tigecycline with anti-Stenotrophomonas agents (i.e. colistin, ticarcillin-clavulanate, ceftazidime, and levofloxacin) was done using the cross Etest method. Genotyping was done using automated repetitive PCR. A total of 90 patients with invasive S. maltophilia infections included: (79%) adults, and 21% children or infants [6/12 (50%) cases occurred in infants aged ≤ 1 year.]. S. maltophilia isolates were recovered from blood (69%), lower respiratory (21%) or other sites (CSF, peritoneal fluid) (11%). Seventeen percent of the isolates were SXT-R, and also demonstrated multi-drug resistant to two or more antibiotic classes. Minocycline, tigecycline and colistin had the best in vitro activities. The combination testing of tigecycline and colistin gave the best results; 12 isolates were tested and synergy occurred in 3 isolates while an additional 7 isolates showed additive results. We recommend further evaluation with killing assays and clinical studies to evaluate the effectiveness of tigecycline and colistin combination for invasive S. maltophilia infections.

Research paper thumbnail of Comparison of the RSV Respi-Strip with Direct Fluorescent-Antigen Detection for Diagnosis of Respiratory Syncytial Virus Infection in Pediatric Patients

Journal of Clinical Microbiology, 2005

The RSV Respi-Strip was compared to the SimulFluor respiratory screen for detecting respiratory s... more The RSV Respi-Strip was compared to the SimulFluor respiratory screen for detecting respiratory syncytial virus in nasopharyngeal aspirates from pediatric patients. Of samples tested, 115/239 (49%) were positive by direct fluorescent-antigen detection. The sensitivity and specificity of the RSV Respi-Strip were 92% (95% confidence interval [CI], 86% to 96%) and 98% (95% CI, 94% to 100%), respectively, with a diagnostic efficiency of 95%.

Research paper thumbnail of Evaluation of StrepB Carrot Broth versus Lim Broth for Detection of Group B Streptococcus Colonization Status of Near-Term Pregnant Women

Journal of Clinical Microbiology, 2008

The performance of StrepB Carrot Broth (SCB) versus group B Lim broth (LIM) for detection of grou... more The performance of StrepB Carrot Broth (SCB) versus group B Lim broth (LIM) for detection of group B streptococcus (GBS) colonization status in near-term pregnant women (35 to 37 weeks of gestation) was evaluated. Dually collected vaginal/rectal swabs from 279 women enrolled from a single large maternity clinic were analyzed. Fifty (18%) women were colonized by GBS according to both methods. SCB had excellent diagnostic performance compared to LIM, with sensitivity, specificity, positive predictive value, and negative predictive value of 92%, 100%, 100%, and 98.3%, respectively. Improved diagnostic efficiency due to direct reporting of GBS cases based on an orange color change in the SCB decreased overall labor and material costs.

Research paper thumbnail of Evaluation of the OSOM Trichomonas Rapid Test versus Wet Preparation Examination for Detection of Trichomonas vaginalis Vaginitis in Specimens from Women with a Low Prevalence of Infection

Journal of Clinical Microbiology, 2008

The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP)... more The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP) for the detection of Trichomonas vaginalis vaginitis in women with a low prevalence of infection. A total of 19/1,009 (2%) women had T. vaginalis infection. OSOM Trich had very good performance, with sensitivity, specificity, efficiency, positive predictive value, and negative predictive value of 94.7, 100, 99.9, 100, and 99.9%, respectively. The implementation of OSOM Trich would decrease labor costs.

Research paper thumbnail of Laboratory Detection of Enterobacteriaceae That Produce Carbapenemases

Journal of Clinical Microbiology, 2012

A study was designed to evaluate the modified Hodge test (MHT), Mastdiscs ID inhibitor combinatio... more A study was designed to evaluate the modified Hodge test (MHT), Mastdiscs ID inhibitor combination disks (MDI), Rosco Diagnostica Neo-Sensitabs (RDS), metallo-␤-lactamase (MBL) Etest, and in-house multiplex PCR for the detection of well-characterized carbapenemase-producing Enterobacteriaceae. One hundred forty-two nonrepeat clinical isolates of carbapenemase-producing Enterobacteriaceae (including Klebsiella spp., Escherichia coli, Citrobacter freundii, and Enterobacter spp.) obtained from the SMART worldwide surveillance program during 2008 to 2009 were included. These included 49 KPC-, 27 NDM-, 19 VIM-, 14 OXA-48-like enzyme-, and 5 IMP-producing isolates and 28 carbapenem-resistant, carbapenemase-negative isolates.

Research paper thumbnail of Identification by 16S rRNA Gene Sequencing of Negativicoccus succinicivorans Recovered from the Blood of a Patient with Hemochromatosis and Pancreatitis

Journal of Clinical Microbiology, 2011

We describe a case of Negativicoccus succinicivorans bacteremia in an adult man with hemochromato... more We describe a case of Negativicoccus succinicivorans bacteremia in an adult man with hemochromatosis and acute pancreatitis. Conventional phenotypic tests and commercial identification systems failed to definitively identify the tiny anaerobic Gram-negative coccus isolated from two sets of blood cultures. The bacterium was identified by 16S rRNA gene sequencing and analysis using the SmartGene Integrated Database Network System software. This is the first published report of the recovery of this organism from a patient with invasive infection.

Research paper thumbnail of P181 Comparison of SmartGene IDNS Software vs. GeneBank for interpretation of partial 16S rRNA gene sequences for bacterial pathogen identification in a clinical laboratory

International Journal of Antimicrobial Agents, 2009

Research paper thumbnail of O66 Comparison of automated repetitive-sequence based PCR and spa-typing using RIDOM™ StaphType database interpretation vs. pulsed-field gel electrophoresis (PFGE) for the molecular typing of methicillin-resistant Staphylococcus aureus (MRSA)

International Journal of Antimicrobial Agents, 2009

Research paper thumbnail of Comparison of the RealTime HIV-1, COBAS TaqMan 48 v1.0, Easy Q v1.2, and Versant v3.0 assays for determination of HIV-1 viral loads in a cohort of Canadian patients with diverse HIV subtype infections

Journal of clinical microbiology, 2011

HIV clinics in Canada provide care to an increasing number of patients born outside of Canada wit... more HIV clinics in Canada provide care to an increasing number of patients born outside of Canada with HIV-1 non-B subtype infections. Because the Easy Q HIV-1 v1.2 assay (EQ; bioMérieux) failed to detect some non-B subtype infections, a multiassay HIV-1 viral load (VL) study was conducted with patients with diverse HIV subtype infections. Patients were enrolled from the Southern Alberta HIV Clinic (SAC), Calgary, Alberta, Canada (n = 349) and the McGill HIV Clinic (MHC), Montreal, Quebec, Canada (n = 20) and had four or five tubes of blood drawn for testing by EQ and three other commercial HIV VL assays: (i) the Versant 3.0 HIV-1 test, with the Versant 440 instrument (branched DNA [bDNA]; Siemens), (ii) the RealTime HIV-1 test, with the m2000rt instrument (m2000rt; Abbott Molecular Diagnostics), and (iii) the COBAS AmpliPrep TaqMan HIV-1 48 test (CAP-CTM; Roche Molecular Diagnostics). Blood was processed according to the individual manufacturer's requirements and stored frozen at ...

Research paper thumbnail of Evaluation of the OSOM Trichomonas Rapid Test versus Wet Preparation Examination for Detection of Trichomonas vaginalis Vaginitis in Specimens from Women with a Low Prevalence of Infection

Journal of Clinical Microbiology, 2008

The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP)... more The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP) for the detection of Trichomonas vaginalis vaginitis in women with a low prevalence of infection. A total of 19/1,009 (2%) women had T. vaginalis infection. OSOM Trich had very good performance, with sensitivity, specificity, efficiency, positive predictive value, and negative predictive value of 94.7, 100, 99.9, 100, and 99.9%, respectively. The implementation of OSOM Trich would decrease labor costs.

Research paper thumbnail of Molecular diagnosis of vaginitis: comparing qPCR and microbiome profiling approaches to current microscopy scoring

Journal of Clinical Microbiology

INTRODUCTION: Vaginitis is often diagnosed by microscopy and limited to testing for bacterial vag... more INTRODUCTION: Vaginitis is often diagnosed by microscopy and limited to testing for bacterial vaginosis (BV), vulvovaginal candidiasis and trichomoniasis. Approximately 10% of vaginal swabs are negative, but designated ‘altered flora' by BV Nugent score, leaving clinicians unsure how to treat patients. Accurate and comprehensive vaginitis diagnostics are needed to direct treatment and reduce risks of recurrent or more severe infections. METHOD: Vaginal swabs were collected from 93 women (mean age: 23.53 yrs, range: 18 – 42 yrs) in a cross-sectional study. Microscopy results for BV and Candida were compared to two molecular approaches, (a) comprehensive qPCR assay including aerobic vaginitis (AV), Candida, STI and BV (Applied Biosystems) with an accompanying BV interpretive algorithm (Coriell Life Sciences) and (b) microbiome profiling of the 16S rRNA gene (Illumina). RESULTS: Microscopy + BV Nugent score had 76% overall agreement with the qPCR + BV interpretive algorithm method ...

Research paper thumbnail of Evaluation of Simplexa Group A Strep Direct Kit Compared to Hologic Group A Streptococcal Direct Assay for Detection of Group A Streptococcus in Throat Swabs

Journal of clinical microbiology, 2018

Diagnosis of bacterial pharyngitis is confirmed by detection of group A (GAS) in patient throat s... more Diagnosis of bacterial pharyngitis is confirmed by detection of group A (GAS) in patient throat samples. Testing of throat samples has historically relied on culture, but new molecular methods allow much faster test turnaround time (i.e., same day versus 48 to 72 h for culture). Our laboratory uses the Hologic GAS Direct (GASD) assay for screening more than 125,000 throat samples per year. Simplexa GAS Direct is a new real-time quantitative PCR (qPCR) assay that does not require initial DNA extraction. Performance of Simplexa qPCR was compared to GASD. A total of 289 throat swabs were collected from patients attending ambulatory clinics in Calgary, Alberta, Canada. A total of 60 (20.8%) of the samples were initially GAS positive by either method: 54 by both methods, 4 by Simplex qPCR alone, and 2 by GASD alone. An in-house PCR using a unique GAS primer set was used to resolve the 6 discrepant results. Overall, GASD compared to Simplexa qPCR had a sensitivity, specificity, positive p...

Research paper thumbnail of Evaluation of StrepB Select Chromagar and the Fast Track Diagnostics Group B Streptococcus (GBS) real-time polymerase chain reaction assay compared to routine culture for detection of GBS during antepartum screening

Journal of clinical microbiology, Jul 26, 2017

Life-threatening infection in neonates due to Group B Streptococcus (GBS) is preventable by scree... more Life-threatening infection in neonates due to Group B Streptococcus (GBS) is preventable by screening near-term pregnant women and treatment at delivery. 295 vaginal-rectal swabs were collected from women attending antepartum clinics in Calgary. GBS colonization was detected by the standard culture method (Strep B Carrot broth subbed to blood agar with a neomycin disk), and compared to recovery using Strep Group B Broth (Dalynn Biologicals) subbed to StrepB Select chromagar (CA) (Bio-Rad Laboratories), and the Fast Track Diagnostics GBS real-time PCR (qPCR) assay (Phoenix Airmid Biomedical Corp.) performed on broth-enriched samples using the Abbott m2000sp/m2000rt system. A total of 62/295 (21%) women were colonized with GBS; 58(19.7%) cases were detected by standard culture while CA and qPCR each found 61 (20.7%) cases. The qPCR vs. CA had similar performance with sensitivity, specificity, PPV and NPV of 98.4% vs. 98.4%, 99.6% vs. 99.6%%, 98.4% vs. 98.4% and 99.6% vs. 99.6% respect...

Research paper thumbnail of Beyond B: HIV-1 viral load multi-assay comparison in a cohort of Canadian patients with diverse HIV subtype infections

Research paper thumbnail of Clinical and economic evaluation of BBL™ CHROMagar™ Salmonella (CHROMSal) versus subculture after selenite broth enrichment to CHROMSal and Hektoen enteric agars to detect enteric Salmonella in a large regional microbiology laboratory

Diagnostic Microbiology and Infectious Disease, Sep 30, 2010

Stool culture for enteric pathogens is one of the most labor-intensive clinical microbiology proc... more Stool culture for enteric pathogens is one of the most labor-intensive clinical microbiology procedures. Direct plating of stool to BBL™ CHROMagar™ Salmonella (CHROMSal) (BD Diagnostics, Sparks, MD) versus subculture after selenite broth enrichment (Sel) to CHROMSal (Sel-CHROMSal) and Hektoen enteric agar (Sel-Hek) (PML Microbiologicals, Eugene, OR) to detect Salmonella were compared. The number of colony picks and biochemical/serotyping tests per plate was recorded. A cost comparison was done. Fifty-one of 2999 (1.7%) stools yielded Salmonella sp., and 80% of isolates grew on CHROMSal by 24 h. CHROMSal demonstrated much less falsepositive growth compared to Sel-Hek (P b 0.0001), which reduced biochemical and serotyping tests by 85% and 20%, respectively. Sel-CHROMSal and CHROMSal versus Sel-Hek improved enteric Salmonella detection when compared to a true positive "gold standard" (i.e., recovery by any culture method) with a sensitivity, specificity, positive predictive value, and negative predictive value of 100% and 94.12%, 100% and 99.97%, 100% and 97.96%, and 100% and 99.90%, respectively. CHROMSal use would result in substantial cost and labor savings.

Research paper thumbnail of HIV-1 viral load multi-assay comparison of the RealTime HIV-1, COBAS TaqMan 48 v 1.0, Easy Q v1. 2 and Versant v3. 0 assays in a cohort of Canadian patients with …

Journal of Clinical …, 2010

... RealTime HIV-1, COBAS 3 TaqMan 48 v 1.0, Easy Q v1.2 and Versant v3.0 assays in a Cohort of C... more ... RealTime HIV-1, COBAS 3 TaqMan 48 v 1.0, Easy Q v1.2 and Versant v3.0 assays in a Cohort of Canadian 4 Patients with Diverse HIV Subtype Infections 5 6 Church, Deirdre1,3,4* , Gregson, Daniel1,3,4 , Tracie Lloyd1, Marina Klein5, Brenda 7 Beckthold2, Kevin Laupland1,4 ...

Research paper thumbnail of Utility of Gram Stain for the Microbiological Analysis of Burn Wound Surfaces

Surface swab cultures have attracted attention as a potential alternative to biopsy histology or ... more Surface swab cultures have attracted attention as a potential alternative to biopsy histology or quantitative culture methods for microbiological burn wound monitoring. To our knowledge, the utility of adding a Gram-stained slide in this context has not been evaluated previously. To determine the degree of correlation of Gram stain with culture for the microbiological analysis of burn wound surfaces. Prospective laboratory analysis. Urban health region/centralized diagnostic microbiology laboratory. Burn patients hospitalized in any Calgary Health Region burn center from November 2000 to September 2001. Gram stain plus culture of burn wound surface swab specimens obtained during routine dressing changes or based on clinical signs of infection. Degree of correlation (complete, high, partial, none), including weighted kappa statistic (kappa(w)), of Gram stain with culture based on quantitative microscopy and degree of culture growth. A total of 375 specimens from 50 burn patients were evaluated. Of these, 239 were negative by culture and Gram stain, 7 were positive by Gram stain only, 89 were positive by culture only, and 40 were positive by both methods. The degree of complete, high, partial, and no correlation of Gram stain with culture was 70.9% (266/375), 1.1% (4/375), 2.4% (9/375), and 25.6% (96/375), respectively. The degree of correlation for all 375 specimens, as expressed by the weighted kappa statistic, was found to be fair (kappa(w) = 0.32).Conclusion.-The Gram stain is not suitable for the microbiological analysis of burn wound surfaces.

Research paper thumbnail of Evaluation of StrepB Carrot Broth versus Lim Broth for Detection of Group B Streptococcus Colonization Status of Near-Term Pregnant Women

Journal of Clinical Microbiology, 2008

The performance of StrepB Carrot Broth (SCB) versus group B Lim broth (LIM) for detection of grou... more The performance of StrepB Carrot Broth (SCB) versus group B Lim broth (LIM) for detection of group B streptococcus (GBS) colonization status in near-term pregnant women (35 to 37 weeks of gestation) was evaluated. Dually collected vaginal/rectal swabs from 279 women enrolled from a single large maternity clinic were analyzed. Fifty (18%) women were colonized by GBS according to both methods. SCB had excellent diagnostic performance compared to LIM, with sensitivity, specificity, positive predictive value, and negative predictive value of 92%, 100%, 100%, and 98.3%, respectively. Improved diagnostic efficiency due to direct reporting of GBS cases based on an orange color change in the SCB decreased overall labor and material costs.

Research paper thumbnail of Evaluation of the OSOM Trichomonas Rapid Test versus Wet Preparation Examination for Detection of Trichomonas vaginalis Vaginitis in Specimens from Women with a Low Prevalence of Infection

Journal of Clinical Microbiology, 2008

The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP)... more The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP) for the detection of Trichomonas vaginalis vaginitis in women with a low prevalence of infection. A total of 19/1,009 (2%) women had T. vaginalis infection. OSOM Trich had very good performance, with sensitivity, specificity, efficiency, positive predictive value, and negative predictive value of 94.7, 100, 99.9, 100, and 99.9%, respectively. The implementation of OSOM Trich would decrease labor costs.

Research paper thumbnail of Utility of Gram Stain for the Microbiological Analysis of Burn Wound Surfaces

Archives of pathology & laboratory medicine

Surface swab cultures have attracted attention as a potential alternative to biopsy histology or ... more Surface swab cultures have attracted attention as a potential alternative to biopsy histology or quantitative culture methods for microbiological burn wound monitoring. To our knowledge, the utility of adding a Gram-stained slide in this context has not been evaluated previously. To determine the degree of correlation of Gram stain with culture for the microbiological analysis of burn wound surfaces. Prospective laboratory analysis. Urban health region/centralized diagnostic microbiology laboratory. Burn patients hospitalized in any Calgary Health Region burn center from November 2000 to September 2001. Gram stain plus culture of burn wound surface swab specimens obtained during routine dressing changes or based on clinical signs of infection. Degree of correlation (complete, high, partial, none), including weighted kappa statistic (kappa(w)), of Gram stain with culture based on quantitative microscopy and degree of culture growth. A total of 375 specimens from 50 burn patients were evaluated. Of these, 239 were negative by culture and Gram stain, 7 were positive by Gram stain only, 89 were positive by culture only, and 40 were positive by both methods. The degree of complete, high, partial, and no correlation of Gram stain with culture was 70.9% (266/375), 1.1% (4/375), 2.4% (9/375), and 25.6% (96/375), respectively. The degree of correlation for all 375 specimens, as expressed by the weighted kappa statistic, was found to be fair (kappa(w) = 0.32).Conclusion.-The Gram stain is not suitable for the microbiological analysis of burn wound surfaces.

Research paper thumbnail of Antimicrobial susceptibility and combination testing of invasive Stenotrophomonas maltophilia isolates

Scandinavian Journal of Infectious Diseases, 2013

Treatment of invasive Stenotrophomonas maltophilia infections is difficult due to this organism&a... more Treatment of invasive Stenotrophomonas maltophilia infections is difficult due to this organism's inherent multidrug resistance and increasing resistance to trimethoprim-sulfamethoxazole via acquisition of the sul genes. In vitro antibiotic susceptibility testing was performed using a customized broth microdilution panel. Combination testing for tigecycline with anti-Stenotrophomonas agents (i.e. colistin, ticarcillin-clavulanate, ceftazidime, and levofloxacin) was done using the cross Etest method. Genotyping was done using automated repetitive PCR. A total of 90 patients with invasive S. maltophilia infections included: (79%) adults, and 21% children or infants [6/12 (50%) cases occurred in infants aged ≤ 1 year.]. S. maltophilia isolates were recovered from blood (69%), lower respiratory (21%) or other sites (CSF, peritoneal fluid) (11%). Seventeen percent of the isolates were SXT-R, and also demonstrated multi-drug resistant to two or more antibiotic classes. Minocycline, tigecycline and colistin had the best in vitro activities. The combination testing of tigecycline and colistin gave the best results; 12 isolates were tested and synergy occurred in 3 isolates while an additional 7 isolates showed additive results. We recommend further evaluation with killing assays and clinical studies to evaluate the effectiveness of tigecycline and colistin combination for invasive S. maltophilia infections.

Research paper thumbnail of Comparison of the RSV Respi-Strip with Direct Fluorescent-Antigen Detection for Diagnosis of Respiratory Syncytial Virus Infection in Pediatric Patients

Journal of Clinical Microbiology, 2005

The RSV Respi-Strip was compared to the SimulFluor respiratory screen for detecting respiratory s... more The RSV Respi-Strip was compared to the SimulFluor respiratory screen for detecting respiratory syncytial virus in nasopharyngeal aspirates from pediatric patients. Of samples tested, 115/239 (49%) were positive by direct fluorescent-antigen detection. The sensitivity and specificity of the RSV Respi-Strip were 92% (95% confidence interval [CI], 86% to 96%) and 98% (95% CI, 94% to 100%), respectively, with a diagnostic efficiency of 95%.

Research paper thumbnail of Evaluation of StrepB Carrot Broth versus Lim Broth for Detection of Group B Streptococcus Colonization Status of Near-Term Pregnant Women

Journal of Clinical Microbiology, 2008

The performance of StrepB Carrot Broth (SCB) versus group B Lim broth (LIM) for detection of grou... more The performance of StrepB Carrot Broth (SCB) versus group B Lim broth (LIM) for detection of group B streptococcus (GBS) colonization status in near-term pregnant women (35 to 37 weeks of gestation) was evaluated. Dually collected vaginal/rectal swabs from 279 women enrolled from a single large maternity clinic were analyzed. Fifty (18%) women were colonized by GBS according to both methods. SCB had excellent diagnostic performance compared to LIM, with sensitivity, specificity, positive predictive value, and negative predictive value of 92%, 100%, 100%, and 98.3%, respectively. Improved diagnostic efficiency due to direct reporting of GBS cases based on an orange color change in the SCB decreased overall labor and material costs.

Research paper thumbnail of Evaluation of the OSOM Trichomonas Rapid Test versus Wet Preparation Examination for Detection of Trichomonas vaginalis Vaginitis in Specimens from Women with a Low Prevalence of Infection

Journal of Clinical Microbiology, 2008

The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP)... more The OSOM Trichomonas rapid test (OSOM Trich) was compared to the wet preparation examination (WP) for the detection of Trichomonas vaginalis vaginitis in women with a low prevalence of infection. A total of 19/1,009 (2%) women had T. vaginalis infection. OSOM Trich had very good performance, with sensitivity, specificity, efficiency, positive predictive value, and negative predictive value of 94.7, 100, 99.9, 100, and 99.9%, respectively. The implementation of OSOM Trich would decrease labor costs.

Research paper thumbnail of Laboratory Detection of Enterobacteriaceae That Produce Carbapenemases

Journal of Clinical Microbiology, 2012

A study was designed to evaluate the modified Hodge test (MHT), Mastdiscs ID inhibitor combinatio... more A study was designed to evaluate the modified Hodge test (MHT), Mastdiscs ID inhibitor combination disks (MDI), Rosco Diagnostica Neo-Sensitabs (RDS), metallo-␤-lactamase (MBL) Etest, and in-house multiplex PCR for the detection of well-characterized carbapenemase-producing Enterobacteriaceae. One hundred forty-two nonrepeat clinical isolates of carbapenemase-producing Enterobacteriaceae (including Klebsiella spp., Escherichia coli, Citrobacter freundii, and Enterobacter spp.) obtained from the SMART worldwide surveillance program during 2008 to 2009 were included. These included 49 KPC-, 27 NDM-, 19 VIM-, 14 OXA-48-like enzyme-, and 5 IMP-producing isolates and 28 carbapenem-resistant, carbapenemase-negative isolates.

Research paper thumbnail of Identification by 16S rRNA Gene Sequencing of Negativicoccus succinicivorans Recovered from the Blood of a Patient with Hemochromatosis and Pancreatitis

Journal of Clinical Microbiology, 2011

We describe a case of Negativicoccus succinicivorans bacteremia in an adult man with hemochromato... more We describe a case of Negativicoccus succinicivorans bacteremia in an adult man with hemochromatosis and acute pancreatitis. Conventional phenotypic tests and commercial identification systems failed to definitively identify the tiny anaerobic Gram-negative coccus isolated from two sets of blood cultures. The bacterium was identified by 16S rRNA gene sequencing and analysis using the SmartGene Integrated Database Network System software. This is the first published report of the recovery of this organism from a patient with invasive infection.

Research paper thumbnail of P181 Comparison of SmartGene IDNS Software vs. GeneBank for interpretation of partial 16S rRNA gene sequences for bacterial pathogen identification in a clinical laboratory

International Journal of Antimicrobial Agents, 2009

Research paper thumbnail of O66 Comparison of automated repetitive-sequence based PCR and spa-typing using RIDOM™ StaphType database interpretation vs. pulsed-field gel electrophoresis (PFGE) for the molecular typing of methicillin-resistant Staphylococcus aureus (MRSA)

International Journal of Antimicrobial Agents, 2009

Research paper thumbnail of Comparison of the RealTime HIV-1, COBAS TaqMan 48 v1.0, Easy Q v1.2, and Versant v3.0 assays for determination of HIV-1 viral loads in a cohort of Canadian patients with diverse HIV subtype infections

Journal of clinical microbiology, 2011

HIV clinics in Canada provide care to an increasing number of patients born outside of Canada wit... more HIV clinics in Canada provide care to an increasing number of patients born outside of Canada with HIV-1 non-B subtype infections. Because the Easy Q HIV-1 v1.2 assay (EQ; bioMérieux) failed to detect some non-B subtype infections, a multiassay HIV-1 viral load (VL) study was conducted with patients with diverse HIV subtype infections. Patients were enrolled from the Southern Alberta HIV Clinic (SAC), Calgary, Alberta, Canada (n = 349) and the McGill HIV Clinic (MHC), Montreal, Quebec, Canada (n = 20) and had four or five tubes of blood drawn for testing by EQ and three other commercial HIV VL assays: (i) the Versant 3.0 HIV-1 test, with the Versant 440 instrument (branched DNA [bDNA]; Siemens), (ii) the RealTime HIV-1 test, with the m2000rt instrument (m2000rt; Abbott Molecular Diagnostics), and (iii) the COBAS AmpliPrep TaqMan HIV-1 48 test (CAP-CTM; Roche Molecular Diagnostics). Blood was processed according to the individual manufacturer's requirements and stored frozen at ...