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Evolution of Neisseria gonorrhoeae is a continuing challenge for molecular detection of gonorrhoea: false negative gonococcal porA mutants are spreading internationally.
Sex Transm Infect. 2013 May; 89(3):197-201.ST

Abstract

OBJECTIVES

Identification of genetic targets specific to Neisseria gonorrhoeae for use in molecular detection methods has been a challenge. The porA pseudogene in N gonorrhoeae has been commonly used but recently gonococcal isolates giving a negative result in these PCRs have been reported. Here we describe the characterisation of two such gonococcal isolates received by the reference service at the Health Protection Agency, London, England.

METHODS

Phenotypic characterisation was achieved using conventional biochemical and immunological tests, matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS), antimicrobial susceptibility testing, serovar determination and detection of meningococcal PorA using monoclonal antibody 4BG4-E7. Genetic species confirmation was determined using commercial and in house PCRs and 16S rRNA gene sequencing. Molecular typing using the N gonorrhoeae multi-antigen sequence typing (NG-MAST) and multilocus sequence typing (MLST) was performed. The DNA sequence of the full-length gonococcal porA pseudogene was determined and compared with published sequences.

RESULTS

Both isolates were confirmed, biochemically and immunologically as N gonorrhoeae, but repeatedly gave negative results with two in house real-time PCR assays for the porA pseudogene. Further characterisation of these isolates identified the presence of a meningococcal porA sequence and showed these isolates belong to serovar Bropyst, and to NG-MAST sequence type (ST) 5967 and MLST ST1901.

CONCLUSIONS

Gonococcal isolates that give false negative results with porA pseudogene PCR assays have now been identified in four countries, three of which are in Europe, and do not appear clonal. This report highlights the genetic diversity of N gonorrhoeae, which remains a challenge for the molecular detection methods.

Authors+Show Affiliations

Sexually Transmitted Bacteria Reference Unit, Health Protection Agency, 61 Colindale Avenue, Colindale, London NW9 5HT, UK. catherine.ison@hpa.org.ukNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23241969

Citation

Ison, Catherine A., et al. "Evolution of Neisseria Gonorrhoeae Is a Continuing Challenge for Molecular Detection of Gonorrhoea: False Negative Gonococcal porA Mutants Are Spreading Internationally." Sexually Transmitted Infections, vol. 89, no. 3, 2013, pp. 197-201.
Ison CA, Golparian D, Saunders P, et al. Evolution of Neisseria gonorrhoeae is a continuing challenge for molecular detection of gonorrhoea: false negative gonococcal porA mutants are spreading internationally. Sex Transm Infect. 2013;89(3):197-201.
Ison, C. A., Golparian, D., Saunders, P., Chisholm, S., & Unemo, M. (2013). Evolution of Neisseria gonorrhoeae is a continuing challenge for molecular detection of gonorrhoea: false negative gonococcal porA mutants are spreading internationally. Sexually Transmitted Infections, 89(3), 197-201. https://doi.org/10.1136/sextrans-2012-050829
Ison CA, et al. Evolution of Neisseria Gonorrhoeae Is a Continuing Challenge for Molecular Detection of Gonorrhoea: False Negative Gonococcal porA Mutants Are Spreading Internationally. Sex Transm Infect. 2013;89(3):197-201. PubMed PMID: 23241969.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evolution of Neisseria gonorrhoeae is a continuing challenge for molecular detection of gonorrhoea: false negative gonococcal porA mutants are spreading internationally. AU - Ison,Catherine A, AU - Golparian,Daniel, AU - Saunders,Pamela, AU - Chisholm,Stephanie, AU - Unemo,Magnus, Y1 - 2012/12/13/ PY - 2012/12/18/entrez PY - 2012/12/18/pubmed PY - 2013/6/19/medline SP - 197 EP - 201 JF - Sexually transmitted infections JO - Sex Transm Infect VL - 89 IS - 3 N2 - OBJECTIVES: Identification of genetic targets specific to Neisseria gonorrhoeae for use in molecular detection methods has been a challenge. The porA pseudogene in N gonorrhoeae has been commonly used but recently gonococcal isolates giving a negative result in these PCRs have been reported. Here we describe the characterisation of two such gonococcal isolates received by the reference service at the Health Protection Agency, London, England. METHODS: Phenotypic characterisation was achieved using conventional biochemical and immunological tests, matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS), antimicrobial susceptibility testing, serovar determination and detection of meningococcal PorA using monoclonal antibody 4BG4-E7. Genetic species confirmation was determined using commercial and in house PCRs and 16S rRNA gene sequencing. Molecular typing using the N gonorrhoeae multi-antigen sequence typing (NG-MAST) and multilocus sequence typing (MLST) was performed. The DNA sequence of the full-length gonococcal porA pseudogene was determined and compared with published sequences. RESULTS: Both isolates were confirmed, biochemically and immunologically as N gonorrhoeae, but repeatedly gave negative results with two in house real-time PCR assays for the porA pseudogene. Further characterisation of these isolates identified the presence of a meningococcal porA sequence and showed these isolates belong to serovar Bropyst, and to NG-MAST sequence type (ST) 5967 and MLST ST1901. CONCLUSIONS: Gonococcal isolates that give false negative results with porA pseudogene PCR assays have now been identified in four countries, three of which are in Europe, and do not appear clonal. This report highlights the genetic diversity of N gonorrhoeae, which remains a challenge for the molecular detection methods. SN - 1472-3263 UR - https://www.unboundmedicine.com/medline/citation/23241969/Evolution_of_Neisseria_gonorrhoeae_is_a_continuing_challenge_for_molecular_detection_of_gonorrhoea:_false_negative_gonococcal_porA_mutants_are_spreading_internationally_ L2 - http://sti.bmj.com/cgi/pmidlookup?view=long&pmid=23241969 DB - PRIME DP - Unbound Medicine ER -