Publications by authors named "Anne Purfield"

17 Publications

  • Page 1 of 1

Four-Month Rifapentine Regimens with or without Moxifloxacin for Tuberculosis.

N Engl J Med 2021 05;384(18):1705-1718

From the Medical University of South Carolina, Charleston (S.E.D.); the UCSF Center for Tuberculosis, University of California, San Francisco, San Francisco (P.N., P.P.J.P., R.M.S.); the Vietnam National Tuberculosis Program-University of California, San Francisco Research Collaboration Unit (P.N., P.P.J.P., H.T.T.P., N.V.N., T.H.P., R.M.S.) and the National Lung Hospital (N.V.N., T.H.P.) - both in Hanoi; the Centers for Disease Control and Prevention, Atlanta (E.V.K., K.B., S.V.G., A.E.P., N.A.S., E.S., A.V.); the University of Texas Health Science Center at San Antonio and the South Texas Veterans Health Care System, San Antonio (M.E., M.W.); the University of Zimbabwe College of Health Sciences, Harare (J.H., W.S.); Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland (J.L.J.); the Uganda-Case Western Reserve University Research Collaboration, Kampala (J.L.J., G.M.); TASK (M.L.), the University of Cape Town Lung Institute (K.N.), and the South African Tuberculosis Vaccine Initiative (J.S.), Cape Town, the Perinatal HIV Research Unit, University of the Witwatersrand (N.A.M., Z.W.), and the Wits Health Consortium (I.S.), Johannesburg - all in South Africa; Johns Hopkins University School of Medicine, Baltimore (K.E.D., N.A.M., R.E.C.), and the U.S. Public Health Service Commissioned Corps, Rockville (A.E.P.) - both in Maryland; the Haitian Group for the Study of Kaposi's Sarcoma and Opportunistic Infections (GHESKIO), Port-au-Prince (S.N., S.P.); and the University of Nebraska Medical Center, Omaha (S.S.).

Background: Rifapentine-based regimens have potent antimycobacterial activity that may allow for a shorter course in patients with drug-susceptible pulmonary tuberculosis.

Methods: In an open-label, phase 3, randomized, controlled trial involving persons with newly diagnosed pulmonary tuberculosis from 13 countries, we compared two 4-month rifapentine-based regimens with a standard 6-month regimen consisting of rifampin, isoniazid, pyrazinamide, and ethambutol (control) using a noninferiority margin of 6.6 percentage points. In one 4-month regimen, rifampin was replaced with rifapentine; in the other, rifampin was replaced with rifapentine and ethambutol with moxifloxacin. The primary efficacy outcome was survival free of tuberculosis at 12 months.

Results: Among 2516 participants who had undergone randomization, 2343 had a culture positive for that was not resistant to isoniazid, rifampin, or fluoroquinolones (microbiologically eligible population; 768 in the control group, 791 in the rifapentine-moxifloxacin group, and 784 in the rifapentine group), of whom 194 were coinfected with human immunodeficiency virus and 1703 had cavitation on chest radiography. A total of 2234 participants could be assessed for the primary outcome (assessable population; 726 in the control group, 756 in the rifapentine-moxifloxacin group, and 752 in the rifapentine group). Rifapentine with moxifloxacin was noninferior to the control in the microbiologically eligible population (15.5% vs. 14.6% had an unfavorable outcome; difference, 1.0 percentage point; 95% confidence interval [CI], -2.6 to 4.5) and in the assessable population (11.6% vs. 9.6%; difference, 2.0 percentage points; 95% CI, -1.1 to 5.1). Noninferiority was shown in the secondary and sensitivity analyses. Rifapentine without moxifloxacin was not shown to be noninferior to the control in either population (17.7% vs. 14.6% with an unfavorable outcome in the microbiologically eligible population; difference, 3.0 percentage points [95% CI, -0.6 to 6.6]; and 14.2% vs. 9.6% in the assessable population; difference, 4.4 percentage points [95% CI, 1.2 to 7.7]). Adverse events of grade 3 or higher occurred during the on-treatment period in 19.3% of participants in the control group, 18.8% in the rifapentine-moxifloxacin group, and 14.3% in the rifapentine group.

Conclusions: The efficacy of a 4-month rifapentine-based regimen containing moxifloxacin was noninferior to the standard 6-month regimen in the treatment of tuberculosis. (Funded by the Centers for Disease Control and Prevention and others; Study 31/A5349 ClinicalTrials.gov number, NCT02410772.).
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http://dx.doi.org/10.1056/NEJMoa2033400DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8282329PMC
May 2021

Central monitoring in a randomized, open-label, controlled phase 3 clinical trial for a treatment-shortening regimen for pulmonary tuberculosis.

Contemp Clin Trials 2021 05 10;104:106355. Epub 2021 Mar 10.

U.S. Centers for Disease Control & Prevention, Atlanta, GA, United States of America.

Introduction: With the growing use of online study management systems and rapid availability of data, timely data review and quality assessments are necessary to ensure proper clinical trial implementation. In this report we describe central monitoring used to ensure protocol compliance and accurate data reporting, implemented during a large phase 3 clinical trial.

Material And Methods: The Tuberculosis Trials Consortium (TBTC) Study 31/AIDS Clinical Trials Group (ACTG) study A5349 (S31) is an international, multi-site, randomized, open-label, controlled, non-inferiority phase 3 clinical trial comparing two 4-month regimens to a standard 6 month regimen for treatment of drug-susceptible tuberculosis (TB) among adolescents and adults with a sample size of 2500 participants.

Results: Central monitoring utilized primary study data in a five-tiered approach, including (1) real-time data checks & topic-specific intervention reports, (2) missing forms reports, (3) quality assurance metrics, (4) critical data reports and (5) protocol deviation identification, aimed to detect and resolve quality challenges. Over the course of the study, 240 data checks and reports were programed across the five tiers used.

Discussion: This use of primary study data to identify issues rapidly allowed the study sponsor to focus quality assurance and data cleaning activities on prioritized data, related to protocol compliance and accurate reporting of study results. Our approach enabled us to become more efficient and effective as we informed sites about deviations, resolved missing or inconsistent data, provided targeted guidance, and gained a deeper understanding of challenges experienced at clinical trial sites.

Trial Registration: This trial was registered with ClinicalTrials.gov (Identifier: NCT02410772) on April 8, 2015.
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http://dx.doi.org/10.1016/j.cct.2021.106355DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8180498PMC
May 2021

High-dose rifapentine with or without moxifloxacin for shortening treatment of pulmonary tuberculosis: Study protocol for TBTC study 31/ACTG A5349 phase 3 clinical trial.

Contemp Clin Trials 2020 03 22;90:105938. Epub 2020 Jan 22.

Audie L. Murphy Veterans Affairs Medical Center / University of Texas Health Science Center, San Antonio, TX, USA.

Introduction: Phase 2 clinical trials of tuberculosis treatment have shown that once-daily regimens in which rifampin is replaced by high dose rifapentine have potent antimicrobial activity that may be sufficient to shorten overall treatment duration. Herein we describe the design of an ongoing phase 3 clinical trial testing the hypothesis that once-daily regimens containing high dose rifapentine in combination with other anti-tuberculosis drugs administered for four months can achieve cure rates not worse than the conventional six-month treatment regimen.

Methods/design: S31/A5349 is a multicenter randomized controlled phase 3 non-inferiority trial that compares two four-month regimens with the standard six-month regimen for treating drug-susceptible pulmonary tuberculosis in HIV-negative and HIV-positive patients. Both of the four-month regimens contain high-dose rifapentine instead of rifampin, with ethambutol replaced by moxifloxacin in one regimen. All drugs are administered seven days per week, and under direct observation at least five days per week. The primary outcome is tuberculosis disease-free survival at twelve months after study treatment assignment. A total of 2500 participants will be randomized; this gives 90% power to show non-inferiority with a 6.6% margin of non-inferiority.

Discussion: This phase 3 trial formally tests the hypothesis that augmentation of rifamycin exposures can shorten tuberculosis treatment to four months. Trial design and standardized implementation optimize the likelihood of obtaining valid results. Results of this trial may have important implications for clinical management of tuberculosis at both individual and programmatic levels.

Trial Registration: NCT02410772. Registered 8 April 2015,https://www.clinicaltrials.gov/ct2/show/NCT02410772?term=02410772&rank=1.
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http://dx.doi.org/10.1016/j.cct.2020.105938DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307310PMC
March 2020

Estimated Prevalence of Cryptococcus Antigenemia (CrAg) among HIV-Infected Adults with Advanced Immunosuppression in Namibia Justifies Routine Screening and Preemptive Treatment.

PLoS One 2016 19;11(10):e0161830. Epub 2016 Oct 19.

Division of Global HIV/AIDS (DGHA), Centers for Disease Control and Prevention (CDC), Windhoek, Namibia.

Background: Cryptococcal meningitis is common and associated with high mortality among HIV infected persons. The World Health Organization recommends that routine Cryptococcal antigen (CrAg) screening in ART-naïve adults with a CD4+ count <100 cells/μL followed by pre-emptive antifungal therapy for CrAg-positive patients be considered where CrAg prevalence is ≥3%. The prevalence of CrAg among HIV adults in Namibia is unknown. We estimated CrAg prevalence among HIV-infected adults receiving care in Namibia for the purpose of informing routine screening strategies.

Methods: The study design was cross-sectional. De-identified plasma specimens collected for routine CD4+ testing from HIV-infected adults enrolled in HIV care at 181 public health facilities from November 2013 to January 2014 were identified at the national reference laboratory. Remnant plasma from specimens with CD4+ counts <200 cells/μL were sampled and tested for CrAg using the IMMY® Lateral Flow Assay. CrAg prevalence was estimated and assessed for associations with age, sex, and CD4+ count.

Results: A total of 825 specimens were tested for CrAg. The median (IQR) age of patients from whom specimens were collected was 38 (32-46) years, 45.9% were female and 62.9% of the specimens had CD4 <100 cells/μL. CrAg prevalence was 3.3% overall and 3.9% and 2.3% among samples with CD4+ counts of CD4+<100 cells/μL and 100-200 cells/μL, respectively. CrAg positivity was significantly higher among patients with CD4+ cells/μL < 50 (7.2%, P = 0.001) relative to those with CD4 cells/μL 50-200 (2.2%).

Conclusion: This is the first study to estimate CrAg prevalence among HIV-infected patients in Namibia. CrAg prevalence of ≥3.0% among patients with CD4+<100 cells/μL justifies routine CrAg screening and preemptive treatment among HIV-infected in Namibia in line with WHO recommendations. Patients with CD4+<100 cells/μL have a significantly greater risk for CrAg positivity. Revised guidelines for ART in Namibia now recommend routine screening for CrAg.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0161830PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5070823PMC
June 2017

Awareness and Environmental Exposures Related to Coccidioidomycosis Among Inmates at Two California Prisons, 2013.

J Correct Health Care 2016 Apr;22(2):157-63

California Correctional Health Care Services, Public Health Branch, Elk Grove, CA, USA.

Coccidioidomycosis (Valley fever) is a major cause of illness in inmates in some California prisons. This article discusses an investigation conducted at two prisons to describe potential environmental exposures. The study did not identify modifiable risk factors; limiting the type or duration of outdoor activity in these prisons may not decrease coccidioidomycosis morbidity.
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http://dx.doi.org/10.1177/1078345816635577DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5661866PMC
April 2016

Notes from the Field: Ebola Virus Disease Response Activities During a Mass Displacement Event After Flooding--Freetown, Sierra Leone, September-November, 2015.

MMWR Morb Mortal Wkly Rep 2016 Feb 26;65(7):188-9. Epub 2016 Feb 26.

Since the start of the Ebola virus disease (Ebola) outbreak in West Africa, Sierra Leone has reported 8,706 confirmed Ebola cases and 3,956 deaths. During September 15-16, 2015, heavy rains flooded the capital, Freetown, resulting in eight deaths, home and property destruction, and thousands of persons in need of assistance. By September 27, approximately 13,000 flood-affected persons registered for flood relief services from the government. On September 17, two stadiums in Freetown were opened to provide shelter and assistance to flood-affected residents; a total of approximately 3,000 persons stayed overnight in both stadiums (Sierra Leone Ministry of Health and Sanitation, personal communication, September 2015). On the same day the stadiums were opened to flood-affected persons, the Ministry of Health and Sanitation (MoHS) and Western Area Ebola Response Center (WAERC) staff members from CDC, the World Health Organization (WHO), and the African Union evaluated the layout, logistics, and services at both stadiums and identified an immediate need to establish Ebola response activities. The patient in the last Ebola case in the Western Area, which includes Freetown, had died 37 days earlier, on August 11; however, transmission elsewhere in Sierra Leone was ongoing, and movement of persons throughout the country was common.
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http://dx.doi.org/10.15585/mmwr.mm6507a4DOI Listing
February 2016

Cardiothoracic surgical site phaeohyphomycosis caused by Bipolaris mould, multiple US states, 2008-2013: a clinical description.

Med Mycol 2016 Mar 24;54(3):318-21. Epub 2015 Dec 24.

Division of Foodborne, Waterborne and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.

Bipolaris mould surgical site infections (SSIs) are exceedingly rare. We describe 21 cases of Bipolaris SSIs in pediatric and adult cardiothoracic surgery patients at ten hospitals in Texas, Arkansas, and Florida during 2008-2013. Median case-patient age was 55 years (range: 3 days-82 years), and 19 (90%) were male. Ten (48%) had coronary artery bypass or valve surgery, and seven (33%) had heart transplantation. Fifteen (71%) had more than one cardiothoracic procedure (median: 3, range: 1-11). Thirteen (62%) case-patients (all 5 pediatric patients, and 8 (50%) of 16 adult patients) had delayed sternal closure (chest closed >1 day [median = 8 days; range: 2-22] following the initial cardiothoracic procedure). Thirteen (62%) had mediastinitis. Median time from initial surgery to positive Bipolaris culture was 20 days (range: 6-497). Sixteen (76%) case-patients died.
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http://dx.doi.org/10.1093/mmy/myv101DOI Listing
March 2016

Development of a Multilocus Sequence Typing System for Medically Relevant Bipolaris Species.

J Clin Microbiol 2015 Oct 22;53(10):3239-46. Epub 2015 Jul 22.

Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Multilocus sequence typing (MLST) is the gold standard genotyping technique for many microorganisms. This classification approach satisfies the requirements for a high-resolution, standardized, and archivable taxonomic system. Here, we describe the development of a novel MLST system to assist with the investigation of an unusual cluster of surgical site infections caused by Bipolaris spp. in postoperative cardiothoracic surgery (POCS) patients during January 2008 to December 2013 in the southeastern United States. We also used the same MLST system to perform a retrospective analysis on isolates from a 2012 Bipolaris endophthalmitis outbreak caused by a contaminated product. This MLST system showed high intraspecies discriminatory power for Bipolaris spicifera, B. hawaiiensis, and B. australiensis. Based on the relatedness of the isolates, the MLST data supported the hypothesis that infections in the POCS cluster were from different environmental sources while confirming that the endophthalmitis outbreak resulted from a point source, which was a contaminated medication.
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http://dx.doi.org/10.1128/JCM.01546-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4572541PMC
October 2015

Fungal infections associated with contaminated methylprednisolone injections.

N Engl J Med 2013 Oct 19;369(17):1598-609. Epub 2012 Dec 19.

From the Epidemic Intelligence Service, Scientific Education and Professional Development Program Office (R.M.S., S.G., A.P.), Division of Foodborne, Waterborne, and Environmental Diseases (R.M.S., A.P., A.A.C., K.B., J.R.H., M.E.B., B.J.P.), Division of Healthcare Quality Promotion (M.K.S., M.W., J.J., J.T.W.), and Division of High-Consequence Pathogens and Pathology (D.B.), Centers for Disease Control and Prevention, Atlanta; the Tennessee Department of Health, Nashville (M.A.K., A.D.W.); the Michigan Department of Community Health, Bureau of Epidemiology, Lansing (J. Finks, J. Fiedler); the Indiana State Department of Health, Indianapolis (J.D., C.F.); the Virginia Department of Health, Richmond (E.F., L.G.); the Maryland Department of Health and Mental Hygiene, Baltimore (A.C.); the New Jersey Department of Health, Trenton (B.C.); the Florida Department of Health, Tallahassee (A.R.); and the North Carolina Division of Public Health, Raleigh (S.G.).

Background: Fungal infections are rare complications of injections for treatment of chronic pain. In September 2012, we initiated an investigation into fungal infections associated with injections of preservative-free methylprednisolone acetate that was purchased from a single compounding pharmacy.

Methods: Three lots of methylprednisolone acetate were recalled by the pharmacy; examination of unopened vials later revealed fungus. Notification of all persons potentially exposed to implicated methylprednisolone acetate was conducted by federal, state, and local public health officials and by staff at clinical facilities that administered the drug. We collected clinical data on standardized case-report forms, and we tested for the presence of fungi in isolates and specimens by examining cultures and performing polymerase-chain-reaction assays and histopathological and immunohistochemical testing.

Results: By October 19, 2012, more than 99% of 13,534 potentially exposed persons had been contacted. As of July 1, 2013, there were 749 reported cases of infection in 20 states, with 61 deaths (8%). Laboratory evidence of Exserohilum rostratum was present in specimens from 153 case patients (20%). Additional data were available for 728 case patients (97%); 229 of these patients (31%) had meningitis with no other documented infection. Case patients had received a median of 1 injection (range, 1 to 6) of implicated methylprednisolone acetate. The median age of the patients was 64 years (range, 15 to 97), and the median incubation period (the number of days from the last injection to the date of the first diagnosis) was 47 days (range, 0 to 249); 40 patients (5%) had a stroke.

Conclusions: Analysis of data from a large, multistate outbreak of fungal infections showed substantial morbidity and mortality. The infections were associated with injection of a contaminated glucocorticoid medication from a single compounding pharmacy. Rapid public health actions included prompt recall of the implicated product, notification of exposed persons, and early outreach to clinicians.
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http://dx.doi.org/10.1056/NEJMoa1213978DOI Listing
October 2013

The diamidine DB75 targets the nucleus of Plasmodium falciparum.

Malar J 2009 May 14;8:104. Epub 2009 May 14.

Department of Microbiology and Immunology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA.

Background: DB289, [2,5-bis(4-amidinophenyl)furan bis-O-methylamidoxime], is a broad spectrum anti-parasitic compound which has been shown to be effective against malaria in recent clinical trials. DB75, [2,5-bis(4-amidinophenyl)furan], is the active metabolite of this drug. The objective of this study was to determine the mechanism of action of DB75 in Plasmodium falciparum.

Methods: Live parasites were observed by confocal microscopy after treatment with organelle specific dyes and DB75, an inherently fluorescent compound. Parasites were exposed to DB75 and assessed for growth and morphological changes over time using blood smears and light microscopy. Also, to determine if DB75 affects gene transcription, real time PCR was used to monitor transcript levels over time for six developmentally expressed genes, including trophozoite antigen R45-like (PFD1175w), lactate dehydrogenase (PF13_0141), DNA primase (PFI0530c), isocitrate dehydrogenase (PF13_0242), merozoite surface protein-1 (PFI1475w), and merozoite surface protein-7 (PF13_0197).

Results: The results show that DB75 localizes in the parasite nucleus but not in other organelles. Once rings are exposed, parasites mature to the trophozoite stage and stall. No stage-dependent or gene-specific inhibition of transcription was seen. However, DB75 delayed peak transcription of trophozoite-stage genes.

Conclusion: Taken together, DB75 appears to concentrate in the nucleus and delay parasite maturation.
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http://dx.doi.org/10.1186/1475-2875-8-104DOI Listing
May 2009

Interactions of DB75, a novel antimalarial agent, with other antimalarial drugs in vitro.

Antimicrob Agents Chemother 2008 Jun 24;52(6):2253-5. Epub 2008 Mar 24.

Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina 27599-7435, USA.

Pafuramidine is a novel orally active antimalarial. To identify a combination partner, we measured the in vitro antimalarial activities of the active metabolite, DB75, with amodiaquine, artemisinin, atovaquone, azithromycin, chloroquine, clindamycin, mefloquine, piperaquine, pyronaridine, tafenoquine, and tetracycline. None of the drugs tested demonstrated antagonistic or synergistic activity in combination with pafuramidine.
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http://dx.doi.org/10.1128/AAC.01536-07DOI Listing
June 2008

Mutations associated with sulfadoxine-pyrimethamine and chlorproguanil resistance in Plasmodium falciparum isolates from Blantyre, Malawi.

Antimicrob Agents Chemother 2005 Sep;49(9):3919-21

Department of Epidemiology, University of North Carolina School of Public Health, Chapel Hill, NC 27599-7435, USA.

We conducted a prevalence study of mutations in Plasmodium falciparum that are associated with antifolate resistance in Blantyre, Malawi. The dihydrofolate reductase 164-Leu mutation, which confers resistance to both pyrimethamine and chlorproguanil, was found in 4.7% of the samples. Previously unreported mutations in dihydropteroate synthase were also found.
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http://dx.doi.org/10.1128/AAC.49.9.3919-3921.2005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1195417PMC
September 2005

pfmdr1 genotyping and in vivo mefloquine resistance on the Thai-Myanmar border.

Am J Trop Med Hyg 2005 May;72(5):586-92

University of North Carolina School of Public Health, Department of Epidemiology, Chapel Hill, North Carolina 27599-7435, USA.

Molecular markers have been proposed as a method of monitoring malaria drug resistance and could potentially be used to prolong the life span of antimalarial drugs. Single nucleotide polymorphisms (SNPs) in the Plasmodium falciparum gene pfmdr1 and increased gene copy number have been associated with in vitro drug resistance but have not been well studied in vivo. In a prospective cohort study of malaria patients receiving mefloquine treatment on the Thai-Myanmar border, there was no significant association between either pfmdr1 SNPs or in vitro drug sensitivity and mefloquine resistance in vivo. Increased pfmdr1 gene copy number was significantly associated with recrudescence (relative risk 2.30, 95% CI 1.27-4.15). pfmdr1 gene copy number may be a useful surveillance tool for mefloquine-resistant falciparum malaria in Thailand.
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May 2005

Prevalence of pfcrt mutations in Congolese and Malawian Plasmodium falciparum isolates as determined by a new Taqman assay.

Acta Trop 2005 Jan;93(1):97-106

Department of Microbiology and Immunology, University of North Carolina School of Medicine, CB 7290, Chapel Hill, NC 27599, USA.

A real-time PCR assay was developed to detect the K76T point mutation in the Plasmodium falciparum putative chloroquine resistance transporter gene. The assay was used with malaria positive clinical isolates from Rutshuru in the eastern part of the Democratic Republic of the Congo (DRC) and from Malawi. The K76T mutation was found in 52/56 (93%) clinical isolates from the DRC, where chloroquine resistance is high, but in none of the 12 isolates tested from Malawi where chloroquine is now rarely used. Sixteen percent of specimens from the DRC had detectable levels of both wild-type and mutant alleles. The real-time PCR results were compared to results from a nested allele-specific PCR assay and from direct DNA sequencing. Using allele-specific PCR as the reference method, the new assay is 100% sensitive and specific towards the mutant allele. In addition to its low per-test cost, the new assay is fast, easily automated, sensitive and well-suited to large-scale epidemiological studies.
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http://dx.doi.org/10.1016/j.actatropica.2004.09.010DOI Listing
January 2005

A new method for detection of pfmdr1 mutations in Plasmodium falciparum DNA using real-time PCR.

Malar J 2004 May 7;3. Epub 2004 May 7.

Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC, USA.

Background: Surveillance for drug-resistant Plasmodium falciparum should be a component of malaria control programmes. Real-time PCR methods for the detection of parasite single-nucleotide polymorphisms (SNPs) and gene amplification could be useful survellance tools.

Methods: A real-time PCR assay has been developed that identifies single nucleotide polymorphisms (SNPs) at amino acids 86, 184, 1034 and 1042 in the P. falciparum multi-drug resistant (pfmdr 1) gene that may be associated with anti-malarial drug resistance.

Results: This assay has a sensitivity and specificity of 94% and 100% when compared to traditional PCR methods for genotyping. Only 54 of 68 (79%) paired pre- and post-culture DNA samples were concordant at all four loci.

Conclusion: Real-time PCR is a sensitive and specific method to detect SNP's in pfmdr 1. Genotypes of parasites after in vitro culture may not reflect that seen in vivo.
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http://dx.doi.org/10.1186/1475-2875-3-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC420476PMC
May 2004

Resistance to antimalarials in Southeast Asia and genetic polymorphisms in pfmdr1.

Antimicrob Agents Chemother 2003 Aug;47(8):2418-23

Department of Epidemiology, University of North Carolina School of Public Health, Chapel Hill, North Carolina, USA.

Resistance to antimalarial drugs is a public health problem worldwide. Molecular markers for drug-resistant malaria, such as pfcrt and pfmdr1 polymorphisms, could serve as useful surveillance tools. To evaluate this possibility, sequence polymorphisms in pfcrt (position 76) and pfmdr1 (positions 86, 184, 1034, 1042, and 1246) and in vitro drug sensitivities were measured for 65 Plasmodium falciparum isolates from Thailand, Myanmar, Vietnam, and Bangladesh. The pfcrt Thr76 polymorphism was present in 97% of samples, consistent with observations that chloroquine resistance is well established in this region. Polymorphisms in pfmdr1 clustered into four specific patterns: the wild type (category I), a Tyr86 polymorphism only (category II), a Phe184 polymorphism only (category III), and Phe184 in combination with Cys1034 and/or Asp1042 (category IV). Isolates in categories I and III were more sensitive to chloroquine and more resistant to mefloquine, artesunate, and artemisinin than isolates in categories II and IV (P /=3. The isolates in all 8 samples fell into categories I and III and were significantly more resistant to mefloquine, quinine, artemisinin, and artesunate and more sensitive to chloroquine than the isolates in the 57 samples with <3 copies of the gene (P
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC166057PMC
http://dx.doi.org/10.1128/AAC.47.8.2418-2423.2003DOI Listing
August 2003
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