scholarly journals False-negative results using Neisseria gonorrhoeae porA pseudogene PCR - a clinical gonococcal isolate with an N. meningitidis porA sequence, Australia, March 2011

2011 ◽  
Vol 16 (21) ◽  
Author(s):  
D M Whiley ◽  
A Limnios ◽  
N J Moon ◽  
N Gehrig ◽  
N Goire ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Sequence Variation ◽  
False Negative ◽  
False Negative Result ◽  
Gonorrhoeae Strain ◽  
Negative Results ◽  
First Case ◽  
False Negative Results

The gonococcal porA pseudogene is a popular target for in-house Neisseria gonorrhoeae PCR methods. With this study we present two novel findings: the first case of an N. gonorrhoeae porA pseudogene PCR false-negative result caused by sequence variation, and in the same organism, the first description of a clinical N. gonorrhoeae strain harbouring an N. meningitidis porA sequence.

scholarly journals Clinical Neisseria gonorrhoeae isolate with a N. meningitidis porA gene and no prolyliminopeptidase activity, Sweden, 2011 – danger of false-negative genetic and culture diagnostic results

2012 ◽  
Vol 17 (9) ◽  
Author(s):  
D Golparian ◽  
E Johansson ◽  
M Unemo
Keyword(s):  
Neisseria Gonorrhoeae ◽  
False Negative ◽  
Gonorrhoeae Strain ◽  
Negative Results ◽  
False Negative Results ◽  
Gonorrhoeae Isolate

We describe a Neisseria gonorrhoeae strain, found in Sweden in 2011, that harbours a N. meningitidis porA gene causing false-negative results in PCRs targeting the gonococcal porA pseudogene. Furthermore, the strain had no prolyliminopeptidase (PIP) activity that many commercial biochemical kits for species verification in culture rely on. Enhanced awareness of the spread of such strains and screening for them can be crucial.

scholarly journals Most but not all laboratories can detect the recently emerged Neisseria gonorrhoeae porA mutants – results from the QCMD 2013 N. gonorrhoeae external quality assessment programme

2014 ◽  
Vol 19 (8) ◽  
Author(s):  
D Luijt ◽  
C Di Lorenzo ◽  
A M van Loon ◽  
M Unemo
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Quality Assessment ◽  
External Quality Assessment ◽  
False Negative ◽  
Molecular Diagnostic ◽  
External Quality ◽  
Diagnostic Assays ◽  
Assessment Programme ◽  
Negative Results ◽  
False Negative Results

We describe the results of the Quality Control for Molecular Diagnostics 2013 Neisseria gonorrhoeae external quality assessment programme that included an N. gonorrhoeae strain harbouring an N. meningitidis porA gene which causes false-negative results in molecular diagnostic assays targeting the gonococcal porA pseudogene. Enhanced awareness of the international transmission of such gonococcal strains is needed to avoid false-negative results in both in-house and commercial molecular diagnostic assays used in laboratories worldwide, but particularly in Europe.

Prevalence of porA pseudogene deletion among Neisseria gonorrhoeae isolates referred to the UK’s Gonococcal Resistance to Antimicrobials Surveillance Program

Sexual Health ◽  
2017 ◽  
Vol 14 (4) ◽  
pp. 392 ◽  
Author(s):  
Martina Toby ◽  
Pamela Saunders ◽  
Michelle Cole ◽  
Vlad Grigorjev ◽  
Sarah Alexander ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
False Negative ◽  
Public Health Problem ◽  
Surveillance Program ◽  
Major Public Health Problem ◽  
Negative Results ◽  
False Negative Results ◽  
Confirmatory Tests ◽  
Polymerase Chain ◽  
Low Prevalence

porA pseudogene-negative Neisseria gonorrhoeae isolates produce false-negative results when examined by polymerase chain reaction (PCR) with porA pseudogene targets. In the present study, 533 representative gonococcal isolates received in 2011 via the Gonococcal Resistance to Antimicrobials Surveillance Program were examined to determine the prevalence of porA-negative isolates. Less than 0.4% (2/533) of isolates were found to be reproducibly negative with the porA real-time PCR but were confirmed as N. gonorrhoeae with molecular, biochemical and immunological confirmatory tests. Sequencing revealed both isolates contained the Neisseria meningitidis porA gene. Low prevalence indicates that although these isolates do not present a major public health problem, microbiologists should remain vigilant.

scholarly journals Rapid diagnostic test negative Plasmodium falciparum malaria in a traveller returning from Ethiopia

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Stefan Schlabe ◽  
Ingrid Reiter-Owona ◽  
Tamara Nordmann ◽  
Ramona Dolscheid-Pommerich ◽  
Egbert Tannich ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Falciparum Malaria ◽  
False Negative ◽  
Plasmodium Falciparum Malaria ◽  
Negative Results ◽  
First Case ◽  
False Negative Results ◽  
Genes Encoding ◽  
Life Threatening ◽  
And Control

Abstract Background Plasmodium falciparum strains with mutations/deletions of the genes encoding the histidine-rich proteins 2/3 (pfhrp2/3) have emerged during the last 10 years leading to false-negative results in HRP2-based rapid diagnostic tests (RDTs). This can lead to unrecognized infections in individuals and to setbacks in malaria control in endemic countries where RDTs are the backbone of malaria diagnostics and control. Case description Here the detection of a pfhrp2/3-negative P. falciparum infection acquired in Ethiopia by a 63-year old female traveller is presented. After onset of symptoms during travel, she was first tested negative for malaria, most probably by RDT, at a local hospital in Harar, Ethiopia. Falciparum malaria was finally diagnosed microscopically upon her return to Germany, over 4 weeks after infection. At a parasite density of approximately 5387 parasites/µl, two different high-quality RDTs: Palutop + 4 OPTIMA, NADALRMalaria PF/pan Ag 4 Species, did not respond at their respective P. falciparum test lines. pfhrp2/3 deletion was confirmed by multiplex-PCR. The patient recovered after a complete course of atovaquone and proguanil. According to the travel route, malaria was acquired most likely in the Awash region, Central Ethiopia. This is the first case of imported P. falciparum with confirmed pfhrp2/3 deletion from Ethiopia. Conclusion HRP2-negative P. falciparum strains may not be recognized by the presently available HRP2-based RDTs. When malaria is suspected, confirmation by microscopy and/or qPCR is necessary in order to detect falciparum malaria, which requires immediate treatment. This case of imported P. falciparum, non-reactive to HRP2-based RDT, possibly underlines the necessity for standardized, nationwide investigations in Ethiopia and should alert clinicians from non-endemic countries to the possibility of false-negative RDT results which may increase in returning travellers with potentially life-threatening infections.

scholarly journals Interpretation of Negative Molecular Test Results in Patients With Suspected or Confirmed Ebola Virus Disease: Report of Two Cases

2015 ◽  
Vol 2 (4) ◽  
Author(s):  
Jeffrey K. Edwards ◽  
Christian Kleine ◽  
Vincent Munster ◽  
Ruggero Giuliani ◽  
Moses Massaquoi ◽  
...  
Keyword(s):  
Ebola Virus ◽  
Virus Disease ◽  
False Negative ◽  
Ebola Virus Disease ◽  
Test Results ◽  
Qrt Pcr ◽  
Negative Results ◽  
First Case ◽  
False Negative Results ◽  
Late Stages

Abstract Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) is the most sensitive quantitative diagnostic assay for detection of Ebola virus in multiple body fluids. Despite the strengths of this assay, we present 2 cases of Ebola virus disease (EVD) and highlight the potential for false-negative results during the early and late stages of EVD. The first case emphasizes the low negative-predictive value of qRT-PCR during incubation and the early febrile stage of EVD, and the second case emphasizes the potential for false-negative results during recovery and late neurologic complications of EVD. Careful interpretation of test results are needed to guide difficult admission and discharge decisions in suspected or confirmed EVD.

scholarly journals PANDAA intentionally violates conventional qPCR design to enable durable, mismatch-agnostic detection of highly polymorphic pathogens

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Iain J. MacLeod ◽  
Christopher F. Rowley ◽  
M. Essex
Keyword(s):  
Sequence Variation ◽  
False Negative ◽  
Site Directed Mutagenesis ◽  
Resistance Mutations ◽  
Emerging Pathogens ◽  
Degenerate Primers ◽  
Negative Results ◽  
False Negative Results ◽  
Mutation Assay ◽  
The Impact

AbstractSensitive and reproducible diagnostics are fundamental to containing the spread of existing and emerging pathogens. Despite the reliance of clinical virology on qPCR, technical challenges persist that compromise their reliability for sustainable epidemic containment as sequence instability in probe-binding regions produces false-negative results. We systematically violated canonical qPCR design principles to develop a Pan-Degenerate Amplification and Adaptation (PANDAA), a point mutation assay that mitigates the impact of sequence variation on probe-based qPCR performance. Using HIV-1 as a model system, we optimized and validated PANDAA to detect HIV drug resistance mutations (DRMs). Ultra-degenerate primers with 3’ termini overlapping the probe-binding site adapt the target through site-directed mutagenesis during qPCR to replace DRM-proximal sequence variation. PANDAA-quantified DRMs present at frequency ≥5% (2 h from nucleic acid to result) with a sensitivity and specificity of 96.9% and 97.5%, respectively. PANDAA is an innovative advancement with applicability to any pathogen where target-proximal genetic variability hinders diagnostic development.

scholarly journals Multitarget PCR Assay for Direct Detection of Penicillinase-Producing Neisseria gonorrhoeae for Enhanced Surveillance of Gonococcal Antimicrobial Resistance

2015 ◽  
Vol 53 (8) ◽  
pp. 2706-2708 ◽  
Author(s):  
Cameron Buckley ◽  
Ella Trembizki ◽  
Robert W. Baird ◽  
Marcus Chen ◽  
Basil Donovan ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Neisseria Gonorrhoeae ◽  
Direct Detection ◽  
False Negative ◽  
Clinical Samples ◽  
Pcr Assay ◽  
Content Type ◽  
Negative Results ◽  
False Negative Results ◽  
Sequence Variations

A multitarget PCR was developed for the direct detection of penicillinase-producing Neisseria gonorrhoeae (PPNG). The assay was validated by testing 342 PPNG isolates and 415 clinical samples. The method is suitable for routine detection of PPNG strains. Its multitarget approach reduces the potential for false-negative results caused by sequence variations.

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