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Nye MB, Harris AB, Pherson AJ, Cartwright CP. Prevalence of Mycoplasma genitalium infection in women with bacterial vaginosis. BMC Womens Health 2020; 20:62. [PMID: 32216785 PMCID: PMC7099815 DOI: 10.1186/s12905-020-00926-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/16/2020] [Indexed: 11/10/2022]
Abstract
Background Bacterial vaginosis (BV) is a common condition in reproductive-age women and is known to be positively associated with risk of acquisition of sexually transmitted infections (STI) such as chlamydia and gonorrhea. Mycoplasma genitalium is an emerging STI that has been linked to increased risk of pelvic inflammatory disease, adverse pregnancy outcomes and infertility. In the present study we sought to examine whether women diagnosed with symptomatic BV were at increased risk of having concurrent infection with Mycoplasma genitalium. Methods We used a novel PCR-based assay (ResistancePlus MG; SpeeDx Pty. Ltd., Sydney, Australia) to determine the prevalence of Mycoplasma genitalium infection and 23S rRNA macrolide-resistance mediating mutations (MRMM) in a cohort of 1532 women presenting with symptoms of vaginitis. Results M. genitalium was detected in 4.0% (62/1532) of samples with 37.1% (23/62) harboring MRMMs. The prevalence of M. genitalium infection in subjects with BV was significantly higher than in subjects with non-BV vaginitis (7.0% v 3.6%; OR = 1.97 (95% CI: 1.14–3.39). Conclusions Prevalence of M. genitalium infection is associated with BV in women with symptomatic vaginitis. Improved management of BV is needed as a component of STI prevention strategies.
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Affiliation(s)
- Melinda B Nye
- Center for Esoteric Testing, Laboratory Corporation of America® Holdings, Burlington, North Carolina, USA
| | - Ayla B Harris
- Center for Esoteric Testing, Laboratory Corporation of America® Holdings, Burlington, North Carolina, USA
| | - Amanda J Pherson
- Center for Esoteric Testing, Laboratory Corporation of America® Holdings, Burlington, North Carolina, USA
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2
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Ackerman SJ, Knight T, Wahl PM, Cartwright CP. Health care utilization and costs following amplified versus non-amplified molecular probe testing for symptomatic patients with suspected vulvovaginitis: a US commercial payer population. Clinicoecon Outcomes Res 2019; 11:179-189. [PMID: 30863131 PMCID: PMC6388970 DOI: 10.2147/ceor.s191831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Vulvovaginitis (VV) is a common reason women seek medical attention in the USA. Both the non-specific clinical presentation and risk of preterm labor or delivery necessitate accurate identification of the causative agents to guide appropriate therapy. The diagnostic accuracy of amplified molecular probe testing (AMP) has been shown to exceed that of non-amplified molecular probe (NAMP) by 20%–25%. Objective To evaluate the impact of diagnosis with AMP testing on health care utilization, direct costs, and health outcomes, compared with NAMP, for symptomatic patients with suspected VV from a commercial payer perspective. Methods Symptomatic women (aged 18–64 years) who underwent VV testing with AMP or NAMP from January 1, 2012–December 31, 2016 were identified using the Truven Health Analytics MarketScan Database; those with continuous medical and pharmacy benefit enrollment 6 months pre/post AMP or NAMP testing were included. Patients were propensity score (PS) matched and 6-month all-cause health care resource utilization, all-cause direct costs (2017 USD), risk of all-cause hospitalization, and risk of preterm labor or delivery were compared between cohorts. Results After PS match (N=46,810 per group, mean age 34.2 years), AMP had significantly (all P<0.0001) fewer mean hospital outpatient visits (AMP 0.9 vs NAMP 1.0), primary care physician office visits (AMP 1.1 vs NAMP 1.2), and prescription medications (AMP 7.3 vs NAMP 8.0), and a 21% reduction in risk of hospitalization (risk ratio [RR]=0.79, 95% CI= 0.75–0.83, P<0.0001). Total medical expenditures per patient were lower for AMP than NAMP (mean AMP $3,287 vs NAMP $3,555, P<0.0001). Among pregnant women (N=2,175 per group), AMP had a 12% reduction in risk of preterm labor or delivery (RR =0.88, 95% CI=0.77–0.99, P=0.041). Conclusion This real-world study offers evidence on the clinical utility for symptomatic patients with suspected VV diagnosed with AMP compared to NAMP – demonstrating an opportunity to improve the patient journey while delivering value-based care.
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Affiliation(s)
| | - Tyler Knight
- Covance Market Access Services Inc., Gaithersburg, MD, USA
| | - Peter M Wahl
- Covance Market Access Services Inc., Gaithersburg, MD, USA
| | - Charles P Cartwright
- Center for Esoteric Testing, Laboratory Corporation of America Holdings, Burlington, NC, USA
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3
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Cartwright CP, Pherson AJ, Harris AB, Clancey MS, Nye MB. Multicenter study establishing the clinical validity of a nucleic-acid amplification-based assay for the diagnosis of bacterial vaginosis. Diagn Microbiol Infect Dis 2018; 92:173-178. [PMID: 29937222 DOI: 10.1016/j.diagmicrobio.2018.05.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/17/2018] [Accepted: 05/24/2018] [Indexed: 11/25/2022]
Abstract
The present study sought to validate the clinical performance of a previously described PCR-based assay for the diagnosis of bacterial vaginosis (BV). A total of 1579 patients were enrolled in 5 locations; samples were classified as BV positive (n=538) or negative (n=1,041) based on an algorithm utilizing quantitative Gram-stain analysis of vaginal discharge and clinical evaluation (Amsel criteria); a next-generation sequencing (NGS) approach to determining diversity of vaginal microbiota was used to resolve discordant results between BV-PCR and Nugent/Amsel. BV-PCR demonstrated a sensitivity of 96.0% (483/503) and a specificity of 90.2% (885/981) when measured against the conventional test standard, with 95 samples (6.0%) being classified as indeterminate. After resolution of discordant results by NGS, including elimination of the PCR indeterminate category, the resolved sensitivity, specificity, and positive and negative predictive values of the BV-PCR assay were 98.7%, 95.9%, 92.9%, and 96.9%, respectively. The results of this study conclusively demonstrate that a relatively simple, 3-biomarker, molecular amplification construct can effectively diagnose BV in symptomatic women. Results generated using this assay were congruent with those obtained using conventional and molecular reference methods.
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Affiliation(s)
- Charles P Cartwright
- Center for Esoteric Testing, Laboratory Corporation of America® Holdings, Burlington, North, Carolina, USA.
| | - Amanda J Pherson
- Center for Esoteric Testing, Laboratory Corporation of America® Holdings, Burlington, North, Carolina, USA
| | - Ayla B Harris
- Center for Esoteric Testing, Laboratory Corporation of America® Holdings, Burlington, North, Carolina, USA
| | - Matthew S Clancey
- Center for Esoteric Testing, Laboratory Corporation of America® Holdings, Burlington, North, Carolina, USA
| | - Melinda B Nye
- Center for Esoteric Testing, Laboratory Corporation of America® Holdings, Burlington, North, Carolina, USA
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4
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Pérez-Losada M, Castel AD, Lewis B, Kharfen M, Cartwright CP, Huang B, Maxwell T, Greenberg AE, Crandall KA. Characterization of HIV diversity, phylodynamics and drug resistance in Washington, DC. PLoS One 2017; 12:e0185644. [PMID: 28961263 PMCID: PMC5621693 DOI: 10.1371/journal.pone.0185644] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 09/16/2017] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Washington DC has a high burden of HIV with a 2.0% HIV prevalence. The city is a national and international hub potentially containing a broad diversity of HIV variants; yet few sequences from DC are available on GenBank to assess the evolutionary history of HIV in the US capital. Towards this general goal, here we analyze extensive sequence data and investigate HIV diversity, phylodynamics, and drug resistant mutations (DRM) in DC. METHODS Molecular HIV-1 sequences were collected from participants infected through 2015 as part of the DC Cohort, a longitudinal observational study of HIV+ patients receiving care at 13 DC clinics. Sequences were paired with Cohort demographic, risk, and clinical data and analyzed using maximum likelihood, Bayesian and coalescent approaches of phylogenetic, network and population genetic inference. We analyzed 601 sequences from 223 participants for int (~864 bp) and 2,810 sequences from 1,659 participants for PR/RT (~1497 bp). RESULTS Ninety-nine and 94% of the int and PR/RT sequences, respectively, were identified as subtype B, with 14 non-B subtypes also detected. Phylodynamic analyses of US born infected individuals showed that HIV population size varied little over time with no significant decline in diversity. Phylogenetic analyses grouped 13.5% of the int sequences into 14 clusters of 2 or 3 sequences, and 39.0% of the PR/RT sequences into 203 clusters of 2-32 sequences. Network analyses grouped 3.6% of the int sequences into 4 clusters of 2 sequences, and 10.6% of the PR/RT sequences into 76 clusters of 2-7 sequences. All network clusters were detected in our phylogenetic analyses. Higher proportions of clustered sequences were found in zip codes where HIV prevalence is highest (r = 0.607; P<0.00001). We detected a high prevalence of DRM for both int (17.1%) and PR/RT (39.1%), but only 8 int and 12 PR/RT amino acids were identified as under adaptive selection. We observed a significant (P<0.0001) association between main risk factors (men who have sex with men and heterosexuals) and genotypes in the five well-supported clusters with sufficient sample size for testing. DISCUSSION Pairing molecular data with clinical and demographic data provided novel insights into HIV population dynamics in Washington, DC. Identification of populations and geographic locations where clustering occurs can inform and complement active surveillance efforts to interrupt HIV transmission.
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Affiliation(s)
- Marcos Pérez-Losada
- Computational Biology Institute, Milken Institute School of Public Health, The George Washington University, Ashburn, VA, United States of America
- CIBIO-InBIO, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal
- Milken Institute School of Public Health, Department of Epidemiology and Biostatistics, The George Washington University, Washington, DC, United States of America
| | - Amanda D. Castel
- Milken Institute School of Public Health, Department of Epidemiology and Biostatistics, The George Washington University, Washington, DC, United States of America
| | - Brittany Lewis
- Milken Institute School of Public Health, Department of Epidemiology and Biostatistics, The George Washington University, Washington, DC, United States of America
| | - Michael Kharfen
- District of Columbia Department of Health, Washington, DC, United States of America
| | | | - Bruce Huang
- Computational Biology Institute, Milken Institute School of Public Health, The George Washington University, Ashburn, VA, United States of America
| | - Taylor Maxwell
- Computational Biology Institute, Milken Institute School of Public Health, The George Washington University, Ashburn, VA, United States of America
| | - Alan E. Greenberg
- Milken Institute School of Public Health, Department of Epidemiology and Biostatistics, The George Washington University, Washington, DC, United States of America
| | - Keith A. Crandall
- Computational Biology Institute, Milken Institute School of Public Health, The George Washington University, Ashburn, VA, United States of America
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5
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Chan PA, Tashima K, Cartwright CP, Gillani FS, Mintz O, Zeller K, Kantor R. Short communication: Transmitted drug resistance and molecular epidemiology in antiretroviral naive HIV type 1-infected patients in Rhode Island. AIDS Res Hum Retroviruses 2011; 27:275-81. [PMID: 20954831 DOI: 10.1089/aid.2010.0198] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Transmission of HIV-1 drug resistance has important clinical and epidemiological consequences including earlier treatment failure and forward transmission of resistance strains in high-risk groups. To evaluate the prevalence and molecular epidemiology of transmitted drug resistance in Rhode Island, we collected genotypic, demographic, clinical, and laboratory data from treatment-naive individuals presenting to the largest outpatient HIV clinic in the state from January 2007 to November 2007. Sequences from 35 treatment-naive individuals were available, 83% of whom were men who had sex with men (MSM). All sequences were HIV-1 subtype B. Drug resistance mutations were identified in 7/35 [20%; 95% confidence interval (CI), 0.08-0.37] patients, six of whom had K103N. Two phylogenetic transmission clusters were found, involving 17% (6/35) of individuals, three in each cluster. We did not find an association between belonging to a cluster and age, gender, AIDS-defining illness, CD4 cell count, or viral load. Drug resistance mutations were more commonly observed in transmission clusters (p = 0.08). Individuals in one cluster all had K103N and were MSM who had attended local bathhouses. Individuals forming clusters were significantly more likely to have visited a bathhouse compared to nonclusters (p = 0.02). The prevalence of transmitted drug resistance in Rhode Island is high, further justifying genotypic testing on presentation to care and prior to treatment initiation. Molecular epidemiological analysis and association of resistance with phylogenetic networks using data obtained for clinical purposes may serve as useful tools for the prevention of drug resistance transmission and for contact tracing.
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Affiliation(s)
- Philip A. Chan
- Division of Infectious Disease, The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Karen Tashima
- Division of Infectious Disease, The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | | | - Fizza S. Gillani
- Division of Infectious Disease, The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Orli Mintz
- Division of Infectious Disease, The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Kimberly Zeller
- Division of Family Medicine, The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Rami Kantor
- Division of Infectious Disease, The Warren Alpert Medical School of Brown University, Providence, Rhode Island
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6
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Stauffer WM, Cartwright CP, Olson DA, Juni BA, Taylor CM, Bowers SH, Hanson KL, Rosenblatt JE, Boulware DR. Diagnostic performance of rapid diagnostic tests versus blood smears for malaria in US clinical practice. Clin Infect Dis 2009; 49:908-13. [PMID: 19686072 PMCID: PMC2912215 DOI: 10.1086/605436] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Approximately 4 million US travelers to developing countries are ill enough to seek health care, with 1500 malaria cases reported in the United States annually. The diagnosis of malaria is frequently delayed because of the time required to prepare malaria blood films and lack of technical expertise. An easy, reliable rapid diagnostic test (RDT) with high sensitivity and negative predictive value (NPV), particularly for Plasmodium falciparum, would be clinically useful. The objective of this study was to determine the diagnostic performance of a RDT approved by the US Food and Drug Administration compared with traditional thick and thin blood smears for malaria diagnosis. METHODS This prospective study tested 852 consecutive blood samples that underwent thick and thin smears and blinded malaria RDTs at 3 hospital laboratories during 2003-2006. Polymerase chain reaction verified positive test results and discordant results. RESULTS Malaria was noted in 95 (11%) of the 852 samples. The RDT had superior performance than the standard Giemsa thick blood smear (p = .003). The RDT's sensitivity for all malaria was 97% (92 of 95 samples), compared with 85% (81 of 95) for the blood smear, and the RDT had a superior NPV of 99.6%, compared with 98.2% for the blood smear (p = .001). The P. falciparum performance was excellent, with 100% rapid test sensitivity, compared with only 88% (65 of 74) by blood smear (p = .003). CONCLUSIONS This operational study demonstrates that the US Food and Drug Administration-approved RDT for malaria is superior to a single set of blood smears performed under routine US clinical laboratory conditions. The most valuable clinical role of the RDT is in the rapid diagnosis or the exclusion of P. falciparum malaria, which is particularly useful in outpatient settings when evaluating febrile travelers.
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Affiliation(s)
- William M Stauffer
- Department of Medicine, Division of Infectious Diseases and International Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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7
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Camargo CA, Ginde AA, Clark S, Cartwright CP, Falsey AR, Niewoehner DE. Viral pathogens in acute exacerbations of chronic obstructive pulmonary disease. Intern Emerg Med 2008; 3:355-9. [PMID: 18825480 DOI: 10.1007/s11739-008-0197-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Accepted: 09/05/2008] [Indexed: 10/21/2022]
Abstract
The objective of this study is to determine the prevalence of respiratory syncytial virus (RSV) and other viral respiratory pathogens in emergency department (ED) patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD). COPD patients presenting to the ED with <10 days of AECOPD symptoms were eligible. We used PCR to test nasal swabs for common viral respiratory pathogens. We completed viral studies on 76 patients from two EDs. Patients had a mean age of 72 years, and were 68% male, 99% white, and 29% current smokers. Influenza vaccination was reported by 87%. Viruses were detected in 19 of 76 patients (25%). These included RSV A (2) and B (4); parainfluenza 1 (1), 2 (0), and 3 (2); influenza A (3) and B (0); rhinovirus (4); and human metapneumovirus (3). A putative viral etiology was identified in 25% of AECOPD presenting for emergency care, of which approximately one-third were RSV-related.
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Affiliation(s)
- Carlos A Camargo
- Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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8
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Chase PB, Hansen KL, Rothers J, Biros MH, Cartwright CP. Nucleic-acid amplification testing of urine vs. patient complaint-driven evaluation. J Emerg Med 2008; 38:572-7. [PMID: 18462909 DOI: 10.1016/j.jemermed.2007.10.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 07/12/2007] [Accepted: 10/30/2007] [Indexed: 10/22/2022]
Abstract
The present pilot study compared the ability of a conventional patient complaint-driven approach to that of nucleic-acid amplification testing (NAAT) of urine to identify those individuals among an adult, urban, Emergency Department (ED) population infected with Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Trichomonas vaginalis (TV). Urine for NAAT was collected for testing after individuals had completed a questionnaire and before being seen by a physician. A total of 614 subjects were enrolled, and complete physical examinations were performed on 348 (56.6%) individuals, with women being significantly more likely to receive such an evaluation (odds ratio [OR] 3.09; 95% confidence interval [CI] 1.96-4.86); p < 0.001). A total of 153 (24.9%) of the study cohort tested positive for a least one sexually transmitted disease (STD), and only a reported history of STD (OR 1.74; 95% CI (1.18-2.57); p = 0.005) and a history of a new sexual partner in the last 3 months (OR 1.79; 95% CI 1.13-2.82); p = 0.012) were predictive of a positive STD test. NAAT of urine samples on patients who did not receive a complete physical examination resulted in a 33% (51/153) increase in diagnostic yield in this cohort of ED attendees.
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Affiliation(s)
- Peter B Chase
- Department of Emergency Medicine, University of Arizona College of Medicine, Tucson, Arizona 85724-5057, USA
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9
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Marshall R, Chernesky M, Jang D, Hook EW, Cartwright CP, Howell-Adams B, Ho S, Welk J, Lai-Zhang J, Brashear J, Diedrich B, Otis K, Webb E, Robinson J, Yu H. Characteristics of the m2000 automated sample preparation and multiplex real-time PCR system for detection of Chlamydia trachomatis and Neisseria gonorrhoeae. J Clin Microbiol 2007; 45:747-51. [PMID: 17202273 PMCID: PMC1829145 DOI: 10.1128/jcm.01956-06] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We evaluated a new real-time PCR-based prototype assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae developed by Abbott Molecular Inc. This assay is designed to be performed on an Abbott m2000 real-time instrument system, which consists of an m2000sp instrument for sample preparation and an m2000rt instrument for real-time PCR amplification and detection. The limit of detection of this prototype assay was determined to be 20 copies of target DNA for both C. trachomatis and N. gonorrhoeae, using serially diluted linearized plasmids. No cross-reactivity could be detected when 55 nongonococcal Neisseria isolates and 3 non-C. trachomatis Chlamydia isolates were tested at 1 million genome equivalents per reaction. Concordance with the Roche Amplicor, BDProbeTec ET, and Gen-Probe APTIMA Combo 2 tests was assessed using unlinked/deidentified surplus clinical specimens previously analyzed with these tests. For C. trachomatis, concordance for positive results ranged from 93.7% to 100%, while concordance for negative results ranged from 98.2% to 100%. For N. gonorrhoeae, concordance for positive and negative results ranged from 91.4% to 100% and 99.3% to 100%, respectively. A workflow analysis of the prototype assay was conducted to obtain information on throughput under laboratory conditions. At 48 samples/run, the time to first result for both C. trachomatis and N. gonorrhoeae was 4.5 h. A total of 135 patient specimens could be analyzed in 8.9 h, with 75 min of hands-on time. This study demonstrated the technical and clinical feasibility of the new Abbott real-time PCR C. trachomatis/N. gonorrhoeae assay.
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Affiliation(s)
- R Marshall
- Abbott Molecular Inc., Des Plaines, IL 60018, USA
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10
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Stauffer WM, Newberry AM, Cartwright CP, Rosenblatt JE, Hanson KL, Sloan L, Tsukayama DT, Taylor C, Juni BA. Evaluation of malaria screening in newly arrived refugees to the United States by microscopy and rapid antigen capture enzyme assay. Pediatr Infect Dis J 2006; 25:948-50. [PMID: 17006296 DOI: 10.1097/01.inf.0000235747.28644.6f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Before an empiric malaria treatment program, >60% of Liberian refugees had malaria on arrival to Minnesota. We compared microscopy with rapid antigen testing for detecting asymptomatic parasitemia. Nine of 103 (8.7%) had malaria by polymerase chain reaction (blood smear and rapid testing had a sensitivity of 22%). The empiric treatment program has decreased the rate of imported asymptomatic malaria. Blood film and rapid antigen testing are poor screening tests.
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Affiliation(s)
- William M Stauffer
- Division of Infectious Disease and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
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Abstract
The past decade has seen a dramatic influx of African-born immigrants and refugees into Minnesota. The impact of this on Hennepin County Medical Center (HCMC), a public teaching hospital located in Minneapolis, has been considerable, especially in the management of HIV-infected persons given that approximately 30% of newly diagnosed individuals seen at HCMC in the past 3 years acquired the virus in Africa. An ongoing and permanent alteration in the demographics of HIV/AIDS in this part of the American midwest is clearly occurring, therefore, accompanied by considerable diversification of the viral makeup of the epidemic. The following article describes currently available data on the viral characteristics of the African-born HIV-infected population of Minnesota and highlights the potential impact of this expanding viral diversity on the ability of the clinical laboratory at HCMC to provide the virologic information necessary to manage effectively patients infected with the HIV virus.
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Affiliation(s)
- Charles P Cartwright
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, Minnesota 55415, USA.
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12
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Hirigoyen DL, Cartwright CP. Use of sequence data generated in the Bayer Tru Gene genotyping assay to recognize and characterize non-subtype-b human immunodeficiency virus type 1 strains. J Clin Microbiol 2005; 43:5263-71. [PMID: 16207993 PMCID: PMC1248470 DOI: 10.1128/jcm.43.10.5263-5271.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Revised: 07/05/2005] [Accepted: 07/11/2005] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) protease (PR) and reverse transcriptase (RT) gene sequences obtained during antiretroviral resistance testing with a commercial genotyping assay (Tru Gene; Bayer Corp.) were analyzed to assess the utility of these data for detecting and characterizing non-subtype-B HIV-1 strains. A total of 125 viral sequences obtained from patients believed to have acquired their HIV-1 infection in Africa were analyzed, of which 121 were determined to belong to non-B subtypes. Utilizing Tru Gene sequence data alone, 92 (76%) of these viruses could be subtyped by conventional phylogenetic analysis. The addition of supplemental RT sequence data enabled a further 28 (23.1%) viruses to be classified, while one (0.9%) sample could not be classified conclusively. Two internet-accessible databases that generate HIV-1 subtypes from PR and RT sequences (HIV-SEQ and Geno 2 Pheno) were also evaluated, and both achieved 88% concordance (106/120) with phylogenetic analysis. Non-subtype-B and B-subtype HIV-1 sequences could be readily discriminated by tallying silent polymorphisms listed on the Tru Gene research report. The mean number of silent polymorphisms in the non-B HIV-1 sequences identified in this study was 58.3 (95% confidence interval [CI], 41.1 to 75.5), compared with 20.7 (95% CI, 9.9 to 31.5) for the four subtype B viruses in the study cohort and 118 case-matched B-subtype controls. Sequence data generated in the Tru Gene HIV-1 genotyping assay could, therefore, provide a ready means of tracking the prevalence and identity of non-B subtypes in HIV-1-infected populations undergoing routine antiretroviral resistance testing.
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Affiliation(s)
- Diane L Hirigoyen
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415, USA
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13
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Skeate RC, Wahi MM, Hanson KL, Cartwright CP. A Study of Results Generated Using the Abbott LCx-GC Assay Fails to Reveal a Performance-Based Rationale for the 2002 Level 1 Recall. Am J Clin Pathol 2005. [DOI: 10.1309/1ld8lu7yffw75wqa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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14
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Skeate RC, Wahi MM, Hanson KL, Cartwright CP. A study of results generated using the Abbott LCx-GC assay fails to reveal a performance-based rationale for the 2002 level 1 recall. Am J Clin Pathol 2005; 123:809-16. [PMID: 15899770 DOI: 10.1309/1ld8-lu7y-ffw7-5wqa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2022] Open
Abstract
To establish the effect of a quality control failure on the performance of the LCx-GC nucleic-acid amplification assay for Neisseria gonorrhoeae (Abbott Laboratories, Abbott Park, IL) in the field, we conducted a retrospective analysis comparing the clinical and analytic performance of the recalled lots with those not implicated in the recall. Our analysis revealed no statistically significant differences between recalled lots (n = 8,686 tests) and nonrecalled lots (n = 8,699 tests) with respect to multiple parameters of assay performance, including frequency distribution of patient results (P = .575), prevalence of indeterminate results (P = .245), mean positive control signals (P = .26), and within-run calibrator precision (P = .68). The LCx-GC system's lack of an electronic data storage and retrieval capability prevented assessment of the impact of the quality control failure on the clinical performance of recalled lots, such as the one described herein, from being conducted in real time.
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Affiliation(s)
- Robert C Skeate
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, USA
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15
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Rauen NC, Wesenberg EM, Cartwright CP. Comparison of selective and nonselective enrichment broth media for the detection of vaginal and anorectal colonization with group B streptococcus. Diagn Microbiol Infect Dis 2005; 51:9-12. [PMID: 15629223 DOI: 10.1016/j.diagmicrobio.2004.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Accepted: 08/23/2004] [Indexed: 11/18/2022]
Abstract
The use of a selective enrichment broth medium has been widely recommended to optimize the recovery of group B streptococci (GBS) from genital and anorectal samples. Because selective antibiotic-containing versions of broth media are significantly more expensive than their nonselective parent formulations, we sought to examine whether the use of the nonselective Todd-Hewitt broth (THB) could accomplish comparable recovery of GBS to the recommended, selective version of this medium (Lim broth). During the study, vaginal and anorectal swab samples submitted to our laboratory for GBS culture were all inoculated onto Columbia colistin-nalidixic acid agar (CNA) and into either THB or Lim broth (alternated on a weekly basis). During the 45-week study period, 1200 samples (600 in each study arm) were evaluated. GBS were recovered from 164 samples (27.3%) in the Lim arm of the study, of which 60 (36.7%) were positive only on subculture of broths. In the THB study arm, 161 samples (26.8%) yielded GBS, of which 58 (36.0%) were positive only in broths. This study conclusively demonstrates that a nonselective enrichment broth media provides comparable sensitivity to the recommended selective broth for detection of GBS colonization during pregnancy.
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Affiliation(s)
- Nancy C Rauen
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415, USA
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16
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Affiliation(s)
- Michael Thrall
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis 55455, USA.
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17
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Stelow EB, Pambuccian SE, Bardales RH, Cartwright CP, Reif CJ, Stanley MW. Loa loa presenting in a ThinPrep Pap test: case report and review of parasites in cervicovaginal cytology specimens. Diagn Cytopathol 2003; 29:167-71. [PMID: 12951687 DOI: 10.1002/dc.10347] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Parasites other than Trichomonas vaginalis may occasionally present in Pap tests obtained during gynecologic examination. We present a case of Loa loa found on a Pap test from an apparently healthy 19-yr-old woman who had immigrated to the US at the age of 15 from Cameroon. We discuss the cytologic features from this case and then briefly review Loa loa and the presence of parasites in Pap tests and other cervicovaginal specimens.
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Affiliation(s)
- Edward B Stelow
- Department of Pathology, Hennepin County Medical Center, Minneapolis, Minnesota 55415, USA.
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18
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Abstract
The ability of a fluconazole-containing agar screen assay to accurately detect isolates of Candida glabrata resistant to the azole antifungal agent fluconazole was evaluated on a collection of 100 clinical isolates of this organism. Results were correlated with the MIC of fluconazole for these isolates and compared with the results of a previously published disk diffusion-based fluconazole resistance screening test. Agar screen assay results were in categorical agreement with MIC-based determinations for 97% (97/100) of the isolates tested. This correlation was higher than that obtained with the disk diffusion technique, which categorized only 87% (87/100) of isolates correctly, and suggests that the agar screening approach can effectively expedite fluconazole susceptibility testing of C. glabrata isolates.
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Affiliation(s)
- Susan M Nelson
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, Minnesota 55415, USA>
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19
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Baker CA, Cartwright CP, Williams DN, Nelson SM, Peterson PK. Early detection of central nervous system tuberculosis with the gen-probe nucleic Acid amplification assay: utility in an inner city hospital. Clin Infect Dis 2002; 35:339-42. [PMID: 12115103 DOI: 10.1086/341494] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2002] [Revised: 03/19/2002] [Indexed: 11/03/2022] Open
Abstract
Central nervous system tuberculosis is a serious clinical problem, the treatment of which is sometimes hampered by delayed diagnosis. We investigated the utility of the Gen-Probe nucleic acid amplification assay for the rapid diagnosis of tuberculous meningitis and as a noninvasive method of identifying intracranial tuberculoma.
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Affiliation(s)
- Cristina A Baker
- Department of Medicine, Hennepin County Medical Center, Minneapolis, MN, 55415, USA.
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20
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Abstract
The promise of the rapidly developing field of pharmacogenetics is that genetically determined propensities of individual patients to respond favorably or adversely to a given pharmacologic agent will be able to be determined prior to administration of that drug. The realization of that promise, however, is predicated on a number of developments in the capabilities of diagnostic laboratories. These developments include the introduction of automated technologies for efficiently and accurately detecting, quantifying and decoding specific nucleic acid sequences and the concomitant availability of information technology-based applications for rapidly analyzing, interpreting and then communicating complex genetic data to healthcare providers. This article will review currently available and developmental molecular diagnostic technology and in addition, describe the current status and speculate on the future of pharmacogenetic testing in the clinical laboratory.
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Affiliation(s)
- C P Cartwright
- Clinical Laboratories, MC #812, Hennepin County Medical Center, 701 Park Ave., Minneapolis, MN 55415, USA.
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21
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Hanson KL, Cartwright CP. Evaluation of an automated liquid-handling system (Tecan Genesis RSP 100) in the Abbott LCx assay for Chlamydia trachomatis. J Clin Microbiol 2001; 39:1975-7. [PMID: 11326027 PMCID: PMC88062 DOI: 10.1128/jcm.39.5.1975-1977.2001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The present study investigated the feasibility of automating the specimen-pipetting component of sample preparation in the LCx Chlamydia assay (LCx-CT assay; Abbott Laboratories, Chicago, Ill.) by using a commercially available liquid-handling system (Tecan Genesis RSP100; Tecan Inc., Research Triangle Park, N.C.). The Tecan instrument proved to be comparable in both precision and accuracy to a manual multipipettor (Eppendorf model 4850; Eppendorf Scientific, Westbury, N.Y.). The Tecan instrument was extensively checked for evidence of specimen-to-specimen transfer, and no level of contamination sufficient to generate a signal above the background in the LCx-CT assay was detected. Finally, pipetting speed was significantly improved by using the Tecan instrument. A mean time of 2.5 min was required to pipette a complete LCx-CT assay carousel (20 samples and 4 controls) with the Tecan instrument, whereas 8.4 min was required to pipette a comparable number of samples manually (P < 0.001).
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Affiliation(s)
- K L Hanson
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, 701 Park Ave., Minneapolis, MN 55415, USA
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22
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Hanson KL, Cartwright CP. Use of an enzyme immunoassay does not eliminate the need to analyze multiple stool specimens for sensitive detection of Giardia lamblia. J Clin Microbiol 2001; 39:474-7. [PMID: 11158092 PMCID: PMC87761 DOI: 10.1128/jcm.39.2.474-477.2001] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2000] [Accepted: 11/05/2000] [Indexed: 12/17/2022] Open
Abstract
The relative sensitivities of a commercially available enzyme immunoassay (EIA) (ProSpecT Giardia; Alexon-Trend Inc., Ramsey, Minn.) and conventional ovum-and-parasite (O&P) examination for the detection of Giardia lamblia in preserved stool specimens were determined. Paired stool samples collected independently within a 7-day period from 103 patients were analyzed by both methods. A total of 54 specimens from 30 patients (18 asymptomatically infected with G. lamblia and 12 with symptoms consistent with intestinal giardiasis) were determined to be positive for G. lamblia, of which 48 (88.9%) were positive by microscopy and 52 (96.3%) were positive by EIA. Both specimens submitted were positive for G. lamblia by O&P examination for 66.7% (20 of 30) of the positive patients; for 26.7% (8 of 30) a single specimen was positive by O&P examination, and for 6.7% (2 of 30) of those determined to be infected with G. lamblia, both samples were negative by microscopy. The sensitivity of conventional O&P examination was somewhat higher in symptomatically infected individuals, with 75% (9 of 12) of patients in this category having G. lamblia detected in both samples, compared with 61% (11 of 18) of asymptomatic patients. A total of 24 positive patients (80%) had G. lamblia antigen detected by EIA in both submitted samples, 4 positive patients (13.3%) had one specimen positive by EIA, and the EIA was negative in both specimens from 2 infected individuals (6.5%), the sensitivity of EIA was substantially equivalent in asymptomatic and symptomatic individuals (77 versus 83% of patients with positive results on both specimens). Although the sensitivity of EIA for the detection of G. lamblia on a single stool specimen was somewhat higher than that of conventional O&P examination in symptomatic patients (83 versus 75%), in asymptomatic patients (77 versus 61%), and overall (80 versus 67%), examination of two specimens by either EIA or microscopy was necessary to achieve a diagnostic sensitivity of greater than 90%.
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Affiliation(s)
- K L Hanson
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, Minnesota 55415, USA
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23
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Fedorko DP, Williams EC, Nelson NA, Mazyck TD, Hanson KL, Cartwright CP. Performance of para-Pak Ultra ECOFIX compared with Para-Pak Ultra formalin/mercuric chloride-based polyvinyl alcohol for concentration and permanent stained smears of stool parasites. Diagn Microbiol Infect Dis 2000; 37:37-9. [PMID: 10794938 DOI: 10.1016/s0732-8893(00)00121-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
ECOFIX is a mercury and formalin-free fecal preservative that can be used for concentration of stool specimens and preparation of permanently-stained slides. In this study, the standard two-vial ParaPak Ultra system was compared with ECOFIX Ultra for the detection of intestinal parasites. A total of 261 specimens in 92 sets (77 with 3 specimens, 15 with 2 specimens) were collected in ECOFIX, formalin, and low viscosity polyvinyl alcohol (LV-PVA). Concentrations were performed from ECOFIX using Hemo-De and saline and from formalin using ethyl acetate and formalin. To prepare permanently-stained smears, ECOSTAIN (a modification of Wheatley's trichrome stain) was used on ECOFIX material and Wheatley's trichrome stain was used on specimens preserved in PVA. A total of 157 protozoa and helminths were detected; 132 (84.1%) were recovered in formalin/PVA and 129 (82.2%) in ECOFIX. In permanently-stained smears, 139 protozoa were observed, 116 (83.5%) in PVA-preserved material and 117 (84.2%) in ECOFIX. Fecal concentration yielded 111 parasites (103 protozoa and 8 helminths), of which 98 (88.3%) were detected in formalin-fixed stool and 48 (43.2%) in ECOFIX. Significantly fewer ECOFIX-preserved concentrates were positive for Blastocystis hominis (35 versus 15, p-value <0.001) and Endolimax nana (19 versus 2, p-value <0.001). In conclusion, use of the ECOFIX Ultra collection device in combination with ECOSTAIN resulted in largely comparable recovery of enteric parasites to the conventional two-vial ParaPak Ultra system when both sedimentation-concentration and permanently stained smears were performed, and 2-3 specimens per patient were evaluated.
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Affiliation(s)
- D P Fedorko
- Microbiology Service, Clinical Pathology Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
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24
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Conville PS, Fischer SH, Cartwright CP, Witebsky FG. Identification of nocardia species by restriction endonuclease analysis of an amplified portion of the 16S rRNA gene. J Clin Microbiol 2000; 38:158-64. [PMID: 10618080 PMCID: PMC86045 DOI: 10.1128/jcm.38.1.158-164.2000] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Identification of clinical isolates of Nocardia to the species level is important for defining the spectrum of disease produced by each species and for predicting antimicrobial susceptibility. We evaluated the usefulness of PCR amplification of a portion of the Nocardia 16S rRNA gene and subsequent restriction endonuclease analysis (REA) for species identification. Unique restriction fragment length polymorphism (RFLP) patterns were found for Nocardia sp. type strains (except for the N. asteroides type strain) and representative isolates of the drug pattern types of Nocardia asteroides (except for N. asteroides drug pattern type IV, which gave inconsistent amplification). A variant RFLP pattern for Nocardia nova was also observed. Twenty-eight clinical isolates were evaluated both by traditional biochemical identification and by amplification and REA of portions of the 16S rRNA gene and the 65-kDa heat shock protein (HSP) gene. There was complete agreement among the three methods on identification of 24 of these isolates. One isolate gave a 16S rRNA RFLP pattern consistent with the biochemical identification but was not identifiable by its HSP gene RFLP patterns. Three isolates gave 16S rRNA RFLP patterns which were inconsistent with the identification obtained by both biochemical tests and HSP gene RFLP; sequence analysis suggested that two of these isolates may belong to undefined species. The PCR and REA technique described appears useful both for the identification of clinical isolates of Nocardia and for the detection of new or unusual species.
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Affiliation(s)
- P S Conville
- Microbiology Service, Clinical Pathology Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland, USA.
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25
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Cartwright CP. Synthetic Viral Particles Promise To Be Valuable in the Standardization of Molecular Diagnostic Assays for Hepatitis C Virus. Clin Chem 1999. [DOI: 10.1093/clinchem/45.12.2057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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26
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Cartwright CP. Synthetic viral particles promise to be valuable in the standardization of molecular diagnostic assays for hepatitis C virus. Clin Chem 1999; 45:2057-9. [PMID: 10585336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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27
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Abstract
A retrospective analysis of the results of 2,704 ova and parasite (O & P) examinations performed on stool specimens collected from 1,374 patients between October 1996 and September 1997 was performed to evaluate the utility of performing O & P examinations on multiple, independently collected stool specimens in a high-prevalence setting. A total of 995 specimens (36.8%) examined during the study contained parasites; 546 (20.2%) contained pathogenic organisms. The positivity rate (54.5%) for the patients from whom three specimens were examined was significantly higher than for the patients from whom either two specimens (33.3%) or a single specimen (19.8%) was submitted for examination. For the group of patients from whom at least 3 specimens were submitted for O & P examination, 373 independent opportunities for diagnosing infection with intestinal parasites could be analyzed. The first stool specimen collected proved to be adequate in only 75.9% (283 of 373) of evaluated cases; however, examination of two specimens increased the sensitivity of O & P detection to 92% (343 of 373). The third specimen collected provided additional information on only 30 of 373 occasions (8%). These data indicate that in populations with a high prevalence of intestinal parasitic infections, two independently collected stool specimens should be subjected to O & P examination to ensure adequate diagnostic sensitivity.
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Affiliation(s)
- C P Cartwright
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, Minnesota 55415, USA.
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28
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Abstract
Three different methodologies, reduction of litmus milk (LM) and acidification of arabinose (ARA), acidification of methyl-alpha-D-glucopyranoside (MGP), and rapid motility (RM), for differentiating isolates of Enterococcus casseliflavus and Enterococcus gallinarum (intrinsically vancomycin-resistant enterococci [IVRE]) from Enterococcus faecalis and Enterococcus faecium were evaluated. All 33 isolates of E. faecalis tested reduced LM within 4 h and were negative in all other tests, while the 53 isolates of E. faecium were ARA positive only. In contrast, 45 of 46 (98%) IVRE isolates examined (26 E. casseliflavus and 20 E. gallinarum isolates) acidified MGP, 41 of 46 (89%) were LM and ARA positive, and 45 of 46 (98%) were RM positive. Acidification of MGP was therefore the single most useful test for differentiating IVRE from vancomycin-resistant E. faecium and E. faecalis; however, a combination of LM-ARA and RM testing enabled the correct designation of organisms without the need for overnight incubation.
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Affiliation(s)
- K L Hanson
- Microbiology Department, Clinical Laboratories, Hennepin County Medical Center, Minneapolis, Minnesota 55415, USA
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29
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Nelson SM, Cartwright CP. Comparison of algorithms for selective use of nucleic-acid probes for identification of Mycobacterium tuberculosis from BACTEC 12B bottles. Diagn Microbiol Infect Dis 1998; 31:537-41. [PMID: 9764392 DOI: 10.1016/s0732-8893(98)00049-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
We retrospectively compared the sensitivity of two approaches, a time-to-detection algorithm and the presence of serpentine cords of acid-fast bacilli, for discriminating between BACTEC 12B cultures containing either Mycobacterium tuberculosis complex (MTB) or Mycobacterium avium complex (MAC). From January 1996 through March 1997 a total of 217 of 2089 respiratory specimens received in our laboratory were positive in the BACTEC 12B radiometric culture system for either MTB (120 specimens) or MAC (97 specimens). Use of a previously published time-to-positivity algorithm would have resulted in the correct use of the MTB probe on 109 of 120 cultures (91% sensitivity), and the MAC probe on 52 of 97 cultures (54% sensitivity). The presence of serpentine cords was detected in 58 of 120 cultures containing MTB (48%), and in 3 of 97 (3%) cultures containing MAC. Using a combination of time to positivity and cord formation to determine initial probe selection would have resulted in first use of the MTB probe in 116 of 120 (97%) instances in which MTB was present in the culture. In only 49 of 97 (51%) cultures, however, from which MAC was recovered would the correct probe have been selected. These results indicate that limiting the initial use of the MTB probe to those cultures that are either identified by the time-to-detection algorithm or demonstrate serpentine cords on acid-fast smear would eliminate a considerable amount of unnecessary probe use without compromising the efficiency of identification of isolates of MTB.
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Affiliation(s)
- S M Nelson
- Microbiology Department, Hennepin County Medical Center, Minneapolis, Minnesota, USA
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30
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Askari S, Cartwright CP. The Changing Epidemiology of Bacterial Meningitis: Implications for the Clinical Laboratory. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s0196-4399(01)80050-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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31
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Abstract
To objectively assess the value of examining multiple sputum specimens in maximizing the sensitivity of detection of Mycobacterium tuberculosis, we retrospectively reviewed the acid-fast bacillus smear and culture results of patients diagnosed with culture-proven pulmonary tuberculosis (TB) at Hennepin County Medical Center between 1986 and 1996. Two hundred and forty six persons were diagnosed with pulmonary TB in the time period analyzed. In 93% of these cases (229 of 246) the laboratory diagnosis was made by detection of M. tuberculosis in sputum specimens; however, only 52% (120 of 229) of these patients had at least three sputum specimens submitted to the laboratory at the time of diagnosis. Of the patients from whom at least three specimens were collected, 47% (56 of 120) had at least one smear-positive specimen; the third or later specimen submitted was the first smear-positive specimen for 13% (7 of 56) of these persons but was the first culture-positive specimen for only 7% (4 of 56). Of the 64 patients with smear-negative specimens, for only 5% (3 of 64) was the third or subsequent specimen submitted the first from which M. tuberculosis was recovered. This data indicates that, in our institution, the overwhelming majority of culture-proven pulmonary TB cases are diagnosed from the first or second sputum specimen submitted to the laboratory and that only rarely is a third specimen of diagnostic value.
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Affiliation(s)
- S M Nelson
- Microbiology Department, Hennepin County Medical Center, Minneapolis, Minnesota 55415, USA
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32
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Collier MC, Stock F, DeGirolami PC, Samore MH, Cartwright CP. Comparison of PCR-based approaches to molecular epidemiologic analysis of Clostridium difficile. J Clin Microbiol 1996; 34:1153-7. [PMID: 8727893 PMCID: PMC228972 DOI: 10.1128/jcm.34.5.1153-1157.1996] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Representative isolates of the 10 serogroups of Clostridium difficile and 39 clinical isolates (30 toxigenic and 9 nontoxigenic), including 5 isolates from a confirmed nosocomial outbreak, were analyzed by using two previously described arbitrary-primer PCR (AP-PCR) molecular typing methodologies (AP-PG05 and AP-ARB11) and PCR ribotyping. The two AP-PCR methods investigated gave comparable results; AP-PG05 and AP-ARB11 identified 8 and 7 groups among the serogroup isolates and classified the clinical isolates into 21 and 20 distinct groups, respectively. PCR ribotyping also identified 8 unique groups among the serogroup isolates but classified the clinical isolates into 23 groups. In addition, when results obtained by the PCR methods were compared with typing data generated by pulsed-field gel electrophoresis (PFGE), PCR ribotyping and PFGE were found to be in agreement for 83% (29 of 35) of isolates typeable by both techniques while AP-PG05 was in agreement with PFGE for 60% (20 of 33) and AP-ARB11 was in agreement with PFGE for only 44% (17 of 36). These results indicate that PCR ribotyping is a more discriminatory approach than AP-PCR for typing C. difficile and, furthermore, that this technique generates results that are in higher concordance with those obtained by using an established method for differentiating isolates of this organism on a molecular level than are results generated by using AP-PCR.
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Affiliation(s)
- M C Collier
- Clinical Pathology Department Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland
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33
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34
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Cartwright CP, Stock F, Fahle GA, Gill VJ. Comparison of pigment production and motility tests with PCR for reliable identification of intrinsically vancomycin-resistant enterococci. J Clin Microbiol 1995; 33:1931-3. [PMID: 7665675 PMCID: PMC228304 DOI: 10.1128/jcm.33.7.1931-1933.1995] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Forty-eight clinical isolates identified as either Enterococcus faecium or Enterococcus faecalis with the MicroScan system (Dade International, MicroScan Inc., West Sacramento, Calif.) were further characterized by two supplementary biochemical tests (pigment production and motility). Twenty isolates (42%), all initially identified as E. faecium, were motile. Of these 20, 8 isolates (17%) produced yellow pigment and were identified as Enterococcus casseliflavus and the remaining 12 (25%) were nonpigmented and were identified as Enterococcus gallinarum. Identical identification results were obtained when PCR amplification of regions of the vanC gene was used as a technique for differentiating these organisms. The results of this study indicate that motility and pigment production tests together with commercial test systems are sufficient for reliable identifications of E. faecium, E. casseliflavus, and E. gallinarum.
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Affiliation(s)
- C P Cartwright
- Clinical Pathology Department, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA
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35
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Abstract
We report the development of a PCR-based assay for the detection of microsporidia in clinical specimens. A single primer pair complementary to conserved sequences of the small-subunit rRNA enabled amplification of DNA from the four major microsporidian pathogens of humans: Encephalitozoon cuniculi, Encephalitozoon hellem, Enterocytozoon bieneusi, and Septata intestinalis. The extraction method allowed PCR amplification of E. bieneusi and S. intestinalis DNA from sodium hypochlorite-treated stool specimens. Differentiation of the microsporidian gastrointestinal pathogens E. bieneusi and S. intestinalis could be accomplished by restriction endonuclease digestion of PCR products using PstI and HaeIII.
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Affiliation(s)
- D P Fedorko
- Clinical Pathology Department, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA
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36
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Cartwright CP, Stock F, Beekmann SE, Williams EC, Gill VJ. PCR amplification of rRNA intergenic spacer regions as a method for epidemiologic typing of Clostridium difficile. J Clin Microbiol 1995; 33:184-7. [PMID: 7699038 PMCID: PMC227904 DOI: 10.1128/jcm.33.1.184-187.1995] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
From January to March 1993, a suspected outbreak of antibiotic-associated diarrhea occurred on a pediatric oncology ward of the Clinical Center Hospital at the National Institutes of Health. Isolates of Clostridium difficile obtained from six patients implicated in this outbreak were typed by both PCR amplification of rRNA intergenic spacer regions (PCR ribotyping) and restriction endonuclease analysis of genomic DNA. Comparable results were obtained with both methods; five of the six patients were infected with the same strain of C. difficile. Subsequent analysis of 102 C. difficile isolates obtained from symptomatic patients throughout the Clinical Center revealed the existence of 41 distinct and reproducible PCR ribotypes. These data suggest that PCR ribotyping provides a discriminatory, reproducible, and simple alternative to conventional molecular approaches for typing strains of C. difficile.
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Affiliation(s)
- C P Cartwright
- Microbiology Service, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892
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37
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Abstract
We report the development of a simplified PCR-based assay for the detection of Pneumocystis carinii DNA in clinical specimens. The adoption of a rapid DNA extraction procedure and the introduction of a type of enzyme-linked immunosorbent assay for PCR product detection enabled this procedure to be carried out in a single working day in a clinical microbiology laboratory. The PCR assay was prospectively compared with an immunofluorescent-antibody (FA) staining method for the detection of P. carinii in induced sputum and bronchoalveolar lavage (BAL) specimens. The results of the study showed that, for induced sputum specimens, FA staining had a sensitivity of 78% (32 of 41 specimens) and a specificity of 100% (166 of 166 specimens); PCR was 100% (41 of 41 specimens) sensitive and 98% (162 of 166 specimens) specific. For BAL specimens, FA staining was 100% sensitive (21 of 21 specimens) and 100% specific (133 of 133 specimens), and PCR had a sensitivity of 100% (21 of 21 specimens) and a specificity of 99% (132 of 133 specimens). These results strongly suggest that use of our PCR-based assay could effect clinically useful improvements in the sensitivity of induced sputum specimens for the detection of P. carinii.
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Affiliation(s)
- C P Cartwright
- Clinical Pathology Department, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892
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38
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Abstract
An enrichment broth developed in our laboratory, fastidious broth (FB), was compared with two commercially available broth media, supplemented thioglycolate broth and enriched eugonic broth. FB supported the growth of a number of organisms that were not cultivatable in either of the other two media, including Corynebacterium jeikeium, Haemophilus influenzae, Neisseria gonorrhoeae, and Streptococcus pneumoniae. In addition, for several organisms that were able to grow in all three broths, including Neisseria meningitidis, Nocardia asteroides, and Actinomyces spp., both the time of incubation and the starting inoculum necessary to enable detection of growth were decreased significantly by using FB.
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Affiliation(s)
- C P Cartwright
- Clinical Pathology Department, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892
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39
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Abstract
K1 preprotoxin is the 316 residue precursor of the K1 killer toxin secreted by the yeast Saccharomyces cerevisiae. The SP beta la reporter consists of the mature, secreted form of beta-lactamase (beta la) fused to S and P, two fragments of preprotoxin. S is the N-terminal 34 residues, including the secretion signal. P, a 67 residue 'processing' segment with three sites for N-glycosylation, terminates in a Lys Arg site for cleavage by the Kex2 protease. Expression of SP beta 1a in yeast results in efficient secretion, processing by signal peptidase and glycosylation in the endoplasmic reticulum, producing pro beta la. Kex2 cleavage of pro beta la in the lumen of a late Golgi compartment releases beta la, which accumulates stably in culture media buffered at pH 5.8-7. The half-life of secretion is 11 min at 30 degrees C; 10-12% of the total activity in exponential-phase cells is intracellular, mostly in the form of pro beta la, indicating that transit from the endoplasmic reticulum to the Golgi is rate limiting. We have used SP beta la expression in single- and multi-copy vectors to compare the PGK, GAL1, GAL10, PHO5 and CUP1 promoters under varying nutritional conditions. In exponential-phase cells, secretion of beta la over a 40-fold range and up to several micrograms/ml was proportional to transcript level, demonstrating that SP beta la can be employed as a convenient secreted reporter of promoter function in yeast.
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Affiliation(s)
- C P Cartwright
- University of Massachusetts Medical School, Department of Molecular Genetics and Microbiology, Worcester 01655
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40
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Abstract
Corynebacterium jeikeium causes systemic infections, particularly in immunocompromised hosts. A minitube assay has been developed for the presumptive identification of C. jeikeium. With our rapid sucrose-urea test and conventional biochemical tests, sixty isolates of gram-positive, catalase-positive bacilli were identified in our laboratory. Results indicated that our assay has a sensitivity of 100% and a specificity of 90%.
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Affiliation(s)
- C P Cartwright
- Clinical Pathology Department, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892
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41
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Ziegler W, Slayman CL, Cartwright CP. Reconstitution of a plasma-membrane H(+)-ATPase into bilayer lipid membrane. Gen Physiol Biophys 1993; 12:429-43. [PMID: 8181690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The plasma membrane H(+)-ATPase of Neurospora has been reconstituted into planar lipid bilayer membranes by means of the vesicle-fusion technique described by Finkelstein and his collaborators (Zimmerberg et al., 1980; Cohen et al., 1980, 1984; Akabas et al., 1984). Enzyme was first transferred from isolated plasma membrane fragments into asolectin vesicles by a detergent-dialysis procedure (Perlin et al., 1984). After H(+)-pumping activity had been checked by quenching of acridine orange fluorescence, the vesicles were fused into performed bilayers. Critical features of the fusion process include (i) attachment of the vesicles to the bilayer in the presence of divalent cations (Mg++), and (ii) rapid osmotic swelling, which was enhanced by prior sonication or freeze-thawing of the vesicles, and/or by inclusions of physiologic channels. Enough proton pumps could be thus incorporated into bilayers to achieve ATP-driven, vanadate-sensitive currents of 0.04-0.4 pA. Aqueous solutions of low ionic strength were used to suppress conductance fluctuations due to the channels, and when that precaution was taken, we could demonstrate the proton pump the work against membrane potentials of at least 50 mV.
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Affiliation(s)
- W Ziegler
- Department of Biophysics and Chemical Physics, Comenius University, Bratislava, Slovakia
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42
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Abstract
The alpha and beta components of the secreted K1 killer toxin of Saccharomyces cerevisiae are derived from residues 45-147 and 234-316, respectively, of the 316 residue preprotoxin (ppTox). The beta N-terminus is produced by Kex2 cleavage after Lys Arg233; when beta la (the mature sequence of beta-lactamase) is fused at this site and the fusion is expressed from the PGK promoter in pDT17, a multicopy plasmid, unexpectedly modest levels of beta la secretion resulted. Over-expression of Kex2 failed to increase beta la secretion while a kex2-null mutation reduced secretion by 98%. beta la secretion in a Kex+ strain was not enhanced by inactivation of the alpha toxin component or by deletion of most of its central hydrophobic segments. However SP-beta la, produced by deletion of ppTox residues 35-176, expressed 10-fold higher beta la activity and the precursor was now secreted with similar efficiency in a kex2-null strain. Fusions of beta la to ppTox at Ala34 or Ala46 also led to efficient secretion in both KEX2 and kex2-null strains. Since these beta la fusions differ only in segments well downstream of the signal peptide and all had similar transcript levels, the efficiency of beta la secretion is apparently determined by the efficiency with which these fusions are translocated to the Golgi compartment where Kex2 is active. Efficiency is high for the shorter fusions, but is 10% or less for the longer fusions; even this fraction is apparently diverted to the vacuole if not cleaved by Kex2. SP-beta la was the most efficient construct tested; secreted beta la reached 4% of total cell protein, modestly exceeding levels produced by fusion to the MF alpha 1-encoded prepro alpha-factor, suggesting potential for the production of foreign proteins in yeast.
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Affiliation(s)
- C P Cartwright
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester 01655
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43
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Abstract
The K1 killer toxin of Saccharomyces cerevisiae consists of 103- and 83-residue alpha and beta components whose derivation, from a 316-residue precursor preprotoxin, requires processing at the alpha N-terminus (after ProArg-44), the alpha C-terminus (after ArgArg-149) and at the beta N-terminus (after LysArg-233). These processing events occur after translocation to the Golgi and have been investigated using beta-lactamase fusions. Signal peptidase cleavage of the precursor, predicted to occur after Ala-26, was confirmed by N-terminal sequence analysis of Ala-34 and Ile-52 fusions. Cleavage at all of the other predicted processing sites, including ProArg-44, is dependent on activity of the Kex2 protease. A fourth Kex2-dependent cleavage occurs at LysArg-188. Implications for the specificity of Kex2 cleavage and preprotoxin processing are discussed.
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Affiliation(s)
- Y S Zhu
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester 01655
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44
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Abstract
Gene fusions were constructed between Ste2, the receptor for the Saccharomyces cerevisiae alpha-factor, and beta la, the secreted form of beta-lactamase encoded by the bla gene of pBR322. The Ste2 and beta la components were linked by a processing fragment (P) from the yeast killer preprotoxin containing a C-terminal lysine-arginine site for cleavage by the Golgi-associated Kex2 protease. Ste2 is predicted to have a rhodopsinlike topology, with an external N terminus and seven transmembrane segments. Fusions to three of the four Ste2 domains predicted to be external resulted in beta la secretion from yeast cells. A fusion at a site just preceding the first transmembrane segment was an exception; the product was cell associated, indicating that the first 44 residues of Ste2 are insufficient to direct secretion of beta la; translocation of this domain presumably requires the downstream transmembrane segment. Expression of fusions located in two domains predicted to be cytoplasmic failed to result in beta la secretion. Following insertion of the preprotoxin signal peptide (S) between the Ste2 and P components of these cytoplasmic fusions, secretion of beta la activity occurred, which is consistent with inversion of the orientation of the beta la reporter. Conversely, insertion of S between Ste2 and P in an external fusion sharply reduced beta la secretion. Complementary information about both cytoplasmic and external domains of Ste2 was therefore provided, and most aspects of the predicted topology were confirmed. The steady-state levels of beta la detected were low, presumably because of efficient degradation of the fusions in the secretory pathway; levels, however, were easily detectable. This method should be valuable in the analysis of in vivo topologies of both homologous and foreign plasma membrane proteins expressed in yeast cells.
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Affiliation(s)
- C P Cartwright
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical Center, Worcester 01655
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Cartwright CP, Veazey FJ, Rose AH. Effect of ethanol on activity of the plasma-membrane ATPase in, and accumulation of glycine by, Saccharomyces cerevisiae. J Gen Microbiol 1987; 133:857-65. [PMID: 2958598 DOI: 10.1099/00221287-133-4-857] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The pH optimum of the ATPase activity in plasma membranes from Saccharomyces cerevisiae NCYC 431 from 8 h cultures was around 6.5 and that in membranes from organisms from 16 h cultures near 6.0. The Km[ATP] of the enzyme was virtually unaffected by the age of the culture from which organisms were harvested, although the Vmax of the enzyme in membranes from organisms from 8 h cultures was higher than that for organisms from 16 h cultures. Ethanol non-competitively inhibited ATPase activity in membranes, although the inhibition constant for the enzyme from organisms from 8 h cultures was lower than that from organisms from 16 h cultures. Glycine accumulation by the general amino acid permease was non-competitively inhibited by ethanol. Inhibition constants were virtually the same for glycine uptake by deenergized organisms from 8 h and 16 h cultures, but under energized conditions the value was greater for organisms from 16 h rather than 8 h cultures. The data indicate that inhibition of plasma-membrane ATPase activity by ethanol could account, at least in part, for inhibition of glycine accumulation by ethanol.
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Affiliation(s)
- C P Cartwright
- Zymology Laboratory, School of Biological Sciences, University of Bath, Avon, UK
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