In large metropolitan areas, which typically have the highest rates of gonorrhea, the identification of chains of transmission by use of partner notification is problematic, and there is an increasing interest in applying molecular approaches, which would require new discriminatory high-throughput procedures for recognizing clusters of indistinguishable gonococci, procedures that identify local chains of transmission. Sequencing of internal fragments of 2 highly polymorphic loci, from 436 isolates recovered in London during a 3-month period, identified clusters of antibiotic-resistant and antibiotic-susceptible isolates with indistinguishable genotypes, the vast majority of which were also identical or closely related by other methods, and defined groups of individuals who typically had similar demographic characteristics. This discriminatory sequence-based approach produces unambiguous data that easily can be compared via the Internet and appears to be suitable for the identification of linked cases of gonorrhea and the timely identification of transmission of antibiotic-resistant strains, even within large cities.

We found a significant burden of this once-rare sexually transmitted infection among MSM in the United Kingdom. LGV may be contributing to the epidemic of human immunodeficiency virus infection by facilitating transmission. Further control efforts are required, including awareness campaigns, continued detailed surveillance, and expanded chlamydia testing among MSM.

These are the first sentinel surveillance data for Western Europe for N. gonorrhoeae and they have implications for choice of antimicrobial for treatment of gonorrhoea on a European and a local level. This is the start of the formation of a European gonococcal antimicrobial surveillance programme (EURO-GASP).

Thirty-three Neisseria gonorrhoeae isolates from 15 persons infected multiple times with the same serovar were compared using por gene sequencing, opa-typing, and arbitrarily primed-polymerase chain reaction. All three molecular techniques were more discriminatory than serotyping and identified differences between some isolates belonging to the same serovar. Although there were differences among Por sequences within some serovars, 10 of 15 subjects became reinfected with gonococci expressing identical Por proteins. Sequence analysis of por genes revealed evidence of horizontal genetic exchange and point mutations in potential surface-exposed regions during passage in the community.

The real-time M-PCR assay simultaneously detects and differentiates LGV from non-LGV strains using swab specimens. This assay offers a relatively rapid and sensitive alternative for the diagnosis of LGV infection and is a useful tool for screening and for outbreak investigations.

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Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST) is a highly discriminatory molecular typing procedure that provides precise and unambiguous strain characterization. Since molecular typing can complement contact tracing for reconstructing gonorrhea sexual networks, the concordance between the NG-MAST genotypes of pairs of N. gonorrhoeae isolates from recent sexual contacts was examined. Among 72 pairs of gonococci from recent sexual contacts, the genotypes of each pair were concordant in 65 cases (90.3%). In two further pairs, the isolates from sexual contacts differed by only a single nonsynonymous substitution in the porin gene, and in both of these pairs, the isolates were the same by opa typing. The other five nonconcordant pairs of isolates were clearly different strains. opa typing data were available for 51 of the pairs of isolates from sexual contacts, and concordant opa types were obtained in 38 cases (74.5%). NG-MAST should therefore be better than opa typing at identifying recent sexual contacts and has the important advantage over opa typing of being a more precise method of strain characterization.Typing of Neisseria gonorrhoeae isolates has provided a valuable adjunct to contact tracing for reconstructing sexual networks (3, 14) and for identifying individuals predicted to be in the same sexual network (2, 6). Phenotypic typing methods for gonococci-for example, the combination of auxotype and serovar-lack sufficient discrimination for this purpose, but a number of more-discriminatory molecular methods have been developed. Of these, pulsed-field gel electrophoresis and opa typing are considered to be the most highly discriminatory but have the disadvantage that they require the comparison of complex DNA fragment patterns on agarose or acrylamide gels (10, 12). More recently there has been a move toward the use of digital data for molecular typing, since this is more suitable for the development of molecular-typing Internet databases and the unambiguous comparison of new isolates with those already deposited in the database. In gonococci, the sequences of the porin (por) gene and fragments of both por and the transferrin-binding protein subunit B gene (tbpB) have been evaluated for molecular typing (9, 11, 13). These genes show high levels of sequence diversity among strains; they are believed to evolve rapidly, because their gene products are surface exposed and are targets of the host immune response to infection. The combination of the sequences at por and tbpB have been used to develop N. gonorrhoeae multiantigen sequence typing (NG-MAST). In this procedure each unique sequence at each locus is given a different allele number, so that a strain is defined unambiguously by two digits, corresponding to the allele numbers at por and tbpB. Each different two-digit number is assigned to a distinct sequence type (ST) that is used to describe the strain (9).Rapid diversification of the loci used to characterize gonococci provides very high levels of discrimination between strains, but too hi...

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