“…The two Af-IB/x strains in which all markers and their combinations coincided, were similar to those described in an outbreak of penicillinase-producing strains of N. gonorrhoeae in the city of Barcelona (close to Valencia) in 1987. 26 The combination of different markers has been shown to give more epidemiological information than the use of only one. Although the restriction enzyme technique appears to be highly specific, it is both laborious and expensive and usually limited to special laboratories.…”