scholarly journals An epidemic CC1-MRSA-IV clone yields false negative test results in molecular MRSA identification assays: a note of caution

2020 ◽  
Author(s):  
Stefan Monecke ◽  
Elisabeth König ◽  
Megan R. Earls ◽  
Eva Leitner ◽  
Elke Müller ◽  
...  
Keyword(s):  
Western Europe ◽  
Integration Site ◽  
False Negative ◽  
Test Results ◽  
Beta Lactam ◽  
Coagulase Negative Staphylococci ◽  
Negative Test ◽  
Link Type ◽  
Junction Site ◽  
False Negative Test

ABSTRACTBackgroundA variety of rapid molecular PCR tests has been developed and commercialised that interrogate the junction site between the staphylococcal core genome, and the mobile genetic element (SCCmec) which harbours the gene responsible for methicillin-/beta-lactam-resistance.AimThe purpose of the present study was to investigate why a clinical MRSA isolate yielded false negative test results with widely used, commercial orfX/SCCmec junction site PCR tests.MethodsA collection of isolates that belonged to the same epidemic strain as the index isolate were investigated with commercial MRSA assays and all isolates were sequenced in order to explain this observation.ResultsIt was found that isolates of the epidemic “European CC1-MRSA-IV” clone, which likely originated in South-Eastern Europe and subsequently spread to Western Europe, generally exhibit this behaviour. The failure of the assays was attributable to a characteristic large insertion in the orfX/SCCmec integration site presumably targeted by such tests. In contrast to MW2 (GenBank BA000033.2, a CC1 “USA400” strain which also harbours SCCmec IVa), the European CC1 clone harbours an insertion of ca. 5,350 nucleotides adjacent to orfX. This sequence starts with a novel SCC terminal sequence alternate to dcs and encodes six different hypothetical proteins (E7MHX1, ydiL2, C5QAP8, A8YYX4, npd-SCC, H4AYD7; nucleotide positions 280,690–286,024 of GenBank RBVO000005.1). An SCCmec element with the same insertion was previously found in a Staphylococcus epidermidis isolate (GenBank MH188467.1) suggesting transfer between staphylococcal species.ConclusionIn order to ensure the reliability of molecular MRSA tests, it is vital to monitor the emergence of new SCCmec junction sites, not only in Staphylococcus aureus but also in coagulase-negative staphylococci.

scholarly journals An epidemic CC1-MRSA-IV clone yields false-negative test results in molecular MRSA identification assays: a note of caution, Austria, Germany, Ireland, 2020

2020 ◽  
Vol 25 (25) ◽  
Author(s):  
Stefan Monecke ◽  
Elisabeth König ◽  
Megan R Earls ◽  
Eva Leitner ◽  
Elke Müller ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Integration Site ◽  
False Negative ◽  
Test Results ◽  
Negative Test ◽  
Negative Results ◽  
False Negative Results ◽  
False Negative Test ◽  
Large Insertion

We investigated why a clinical meticillin-resistant Staphylococcus aureus (MRSA) isolate yielded false-negative results with some commercial PCR tests for MRSA detection. We found that an epidemic European CC1-MRSA-IV clone generally exhibits this behaviour. The failure of the assays was attributable to a large insertion in the orfX/SCCmec integration site. To ensure the reliability of molecular MRSA tests, it is vital to monitor emergence of new SCCmec types and junction sites.

Incidence and Recovery of Salmonellae and Other Bacteria from Commercially Processed Poultry Carcasses at Selected Pre- and Post-Evisceration Steps

1989 ◽  
Vol 52 (2) ◽  
pp. 88-91 ◽  
Author(s):  
H. S. LILLARD
Keyword(s):  
False Negative ◽  
Aerobic Bacteria ◽  
Processing Plant ◽  
Test Results ◽  
Negative Test ◽  
Commercial Plant ◽  
Sampling Points ◽  
Processing Line ◽  
False Negative Test ◽  
Progressive Sampling

This study was undertaken to determine whether bacteria are already attached to poultry skin when birds arrive at the processing plant. Multiple rinses were performed on breast skin and whole carcasses taken from five processing points in a commercial plant: Before scalding, after scalding, after picking, after the final washer, and from the exit end of the chiller. Aerobic bacteria and Enterobacteriaceae were recovered from carcasses in up to 40 consecutive whole carcass rinses with a difference of only about one log for Enterobacteriaceae, and 1 to 2 logs for aerobes from the first to the last rinse of carcasses taken from the beginning and the end of the processing line. Data from rinses prior to scalding indicated that bacteria were firmly attached to poultry carcasses when they first arrived in the plant. Not all bacteria were removed during processing; however, there were fewer aerobes and Enterobacteriaceae at progressive sampling points. Attached salmonellae were not always recovered in the first whole carcass rinse, but were sometimes recovered in 3rd, 5th, and 10th rinses. These data show that a single whole carcass rinse can result in false negative test results for salmonellae. Because of the small number of positive samples in this study, the probability of recovering salmonellae with a single whole carcass rinse could not be estimated accurately.

scholarly journals False-negative test results to non-agglutinating (incomplete) antibodies.

1982 ◽  
Vol 58 (4) ◽  
pp. 275-276
Author(s):  
E de Klerk ◽  
C A Sharp ◽  
C Geffen ◽  
R Anderson
Keyword(s):  
False Negative ◽  
Test Results ◽  
Negative Test ◽  
False Negative Test

Risk factors for false positive and for false negative test results in screening with fecal occult blood testing

2013 ◽  
Vol 133 (10) ◽  
pp. 2408-2414 ◽  
Author(s):  
Inge Stegeman ◽  
Thomas R. de Wijkerslooth ◽  
Esther M. Stoop ◽  
Monique van Leerdam ◽  
M. van Ballegooijen ◽  
...  
Keyword(s):  
Risk Factors ◽  
False Positive ◽  
False Negative ◽  
Occult Blood ◽  
Fecal Occult Blood Testing ◽  
Fecal Occult Blood ◽  
Test Results ◽  
Negative Test ◽  
Fecal Occult ◽  
False Negative Test

scholarly journals Informed choice on Pap smear still limited by lack of knowledge on the meaning of false-positive or false-negative test results

2011 ◽  
Vol 85 (2) ◽  
pp. 214-218 ◽  
Author(s):  
Ida J. Korfage ◽  
Marjolein van Ballegooijen ◽  
Brendy Wauben ◽  
J. Dik F. Habbema ◽  
Marie-Louise Essink-Bot
Keyword(s):  
False Positive ◽  
Pap Smear ◽  
False Negative ◽  
Informed Choice ◽  
Test Results ◽  
Negative Test ◽  
False Negative Test ◽  
Lack Of Knowledge

RE: “PROBABILITY OF INTRODUCING DISEASES BECAUSE OF FALSE NEGATIVE TEST RESULTS”

1991 ◽  
Vol 133 (3) ◽  
pp. 321-321 ◽  
Author(s):  
Margaret A. Thorburn ◽  
John J. McDermott ◽  
S. Wayne Martin
Keyword(s):  
False Negative ◽  
Test Results ◽  
Negative Test ◽  
False Negative Test

scholarly journals COVID-19 Testing: Challenges, Limitations and Suggestions for Improvement

2020 ◽  
Author(s):  
Emily Hu
Keyword(s):  
False Negative ◽  
Diagnostic Methods ◽  
Test Results ◽  
Successful Management ◽  
Negative Test ◽  
Reliable Methods ◽  
False Negative Test

Reliable methods to confirm the diagnosis of COVID-19 are essential to the successful management and containment of the virus. Current diagnostic options are limited in type, supply, and reliability. This article explores the controversial unreliability of existing diagnostic methods and maintains that more reliable diagnostic methods, combinations, and sequencing are necessary to effectively assist in reducing the occurrence of discharge of the patient on false negative test results. This reduction would in effect reduce transmission of the disease.

scholarly journals Qualitative Variation among Commercial Immunoassays for Detection of Measles-Specific IgG

2020 ◽  
Vol 58 (6) ◽  
Author(s):  
Donald R. Latner ◽  
Sun B. Sowers ◽  
Kiana Anthony ◽  
Heather Colley ◽  
Christine Badeau ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Measles Virus ◽  
False Negative ◽  
Test Results ◽  
Serum Samples ◽  
Gold Standard Method ◽  
Negative Test ◽  
Specific Igg ◽  
False Negative Test

ABSTRACT Measurement of measles virus-specific IgG is used to assess presumptive evidence of immunity among immunocompetent individuals with uncertain immune or vaccination status. False-negative test results may lead to unnecessary quarantine and exclusion from activities such as employment, education, and travel or result in unnecessary revaccination. In contrast, false-positive results may fail to identify susceptible individuals and promote spread of disease by those who are exposed and unprotected. To better understand the performance characteristics of tests to detect measles IgG, we compared five widely used, commercially available measles IgG test platforms using a set of 223 well-characterized serum samples. Measles virus neutralizing antibodies were also measured by in vitro plaque reduction neutralization, the gold standard method, and compared to IgG test results. Discrepant results were observed for samples in the low-positive ranges of the most sensitive tests, but there was good agreement across platforms for IgG-negative sera and for samples with intermediate to high levels of IgG. False-negative test results occurred in approximately 11% of sera, which had low levels of neutralizing antibody.

Sign in / Sign up

Export Citation Format

Share Document