Neisseria gonorrhoeae: evaluation of some methods used for carbohydrate utilization

1978 ◽  
Vol 24 (2) ◽  
pp. 177-181 ◽  
Author(s):  
Rosa Shtibel ◽  
S. Toma
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Acid Production ◽  
Carbohydrate Utilization ◽  
Neisseria Species ◽  
Negative Results

A total of 989 Neisseria gonorrhoeae cultures were examined for acid production from dextrose in seven different carbohydrate media. Four of these media were found to be quite accurate for this purpose. Some pitfalls in the preparation and usage of cystine trypticase agar carbohydrate media are discussed. The term 'fermentation' of carbohydrates by Neisseria species is inaccurate and responsible for some N. gonorrhoeae false-dextrose-negative results.

Exploring 'best practice' for nucleic acid detection of Neisseria gonorrhoeae

Sexual Health ◽  
2008 ◽  
Vol 5 (1) ◽  
pp. 17 ◽  
Author(s):  
David M. Whiley ◽  
Suzanne M. Garland ◽  
Geoffrey Harnett ◽  
Gary Lum ◽  
David W. Smith ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Neisseria Gonorrhoeae ◽  
Best Practice ◽  
Current Knowledge ◽  
False Negative ◽  
High Sensitivity ◽  
Nucleic Acid Detection ◽  
Predictive Values ◽  
Neisseria Species ◽  
Negative Results

Nucleic acid detection tests (NADT) have considerable benefits for the detection of Neisseria gonorrhoeae (GC), including high sensitivity across a range of specimen types and use under widely differing settings and conditions. However, sexual health practitioners and others who use data generated by NADT for GC should be aware of some important limitations of these tests. False-positive results caused by cross reaction with commensal Neisseria species have been observed in many assays, and have lead to unacceptably low positive-predictive values in some patient populations. Further, false-negative results can be caused by GC sequence variation, with some gonococci lacking certain NADT target sequences. This review examines the issues associated with gonococcal NADT and considers best practice for use of these assays based on current knowledge. We emphasise the need for supplementary testing and extensive assay validation, and suggest appropriate strategies for these requirements irrespective of the setting in which they are used. Further, we highlight the need to maintain culture-based testing for certain specimen sites as well as for antimicrobial resistance surveillance.

Rapid micro-carbohydrate test for confirmation of Neisseria gonorrhoeae

1978 ◽  
Vol 8 (6) ◽  
pp. 643-647
Author(s):  
D C Yong ◽  
A Prytula
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Small Volume ◽  
Clinical Isolates ◽  
Carbohydrate Utilization ◽  
Neisseria Species ◽  
Combined Use ◽  
Glass Tubes

A rapid carbohydrate utilization procedure for the confirmation of Neisseria gonorrhoeae and identification of other Neisseria species has been developed. This method utilizes both preformed enzymes, introduced in a heavy inoculum, and enzymes formed by the microorganisms as a result of growth in a small volume of super-enriched medium. Expected carbohydrate reactions were produced by 383 clinical isolates of neisseriae and were clearly visible within 4 h of incubation. The combined use of disposable glass tubes (6 by 50 mm) and microamounts of media (0.05 ml) make this method not only rapid, but also low in cost.

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.

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.

Comparison of three methods for identification of pathogenic Neisseria species

1979 ◽  
Vol 9 (5) ◽  
pp. 598-600
Author(s):  
P C Appelbaum ◽  
R B Lawrence
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Neisseria Meningitidis ◽  
Incubation Period ◽  
Fluorescent Antibody ◽  
Neisseria Species ◽  
Neisseria Lactamica ◽  
Sugar Degradation ◽  
Agar Method ◽  
Neisseria Sicca

A radiometric procedure was compared with the Minitek and Cystine Trypticase Agar sugar degradation methods for identification of 113 Neisseria species (58 Neisseria meningitidis, 51 Neisseria gonorrhoeae, 2 Neisseria lactamica, 2 Neisseria sicca). Identification of meningococci and gonococci was confirmed by agglutination and fluorescent antibody techniques, respectively. The Minitek method identified 97% of meningococci, 92% of gonococci, and 100% of other Neisseria after 4 h of incubation. The radiometric (Bactec) procedure identified 100% of gonococci and 100% of miscellaneous Neisseria after 3 h, but problems were encountered with meningococci: 45% of the later strains yielded index values for fructose between 20 and 28 (recommended negative cut-off point, less than 20), with strongly positive (greater than 100) glucose and maltose and negative o-nitrophenyl-beta-D-galactopyranoside reactions in all 58 strains. The Cystine Trypticase Agar method identified 91% of meningococci, 90% of gonococci, and 100% of other Neisseria after 24 to 48 h. Prolongation of the Cystine Trypticase Agar incubation period led to abnormal lactose/sucrose reactions in some meningococci and gonococci. Radiometric and Minitek systems are more accurate and convenient than Cystine Trypticase Agar techniques, but, on the basis of these results, radiometric fructose sensitivity levels for meningococci need reevaluation.

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.

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