Pulsed-field gel electrophoresis as an epidemiologic tool for Neisseria gonorrhoeae: identification of clusters within serovars.
BACKGROUND
The increasing incidence of gonorrhea in Sweden in 1998 was due to mostly domestic cases. Among these, two core groups were identified: homosexual men with serovar IB-2 and young heterosexuals with serovar IB-3.


OBJECTIVE
To explore the genetic homogeneity/heterogeneity within the predominant serovars, IB-2 and IB-3, of Neisseria gonorrhoeae in Sweden by pulsed-field gel electrophoresis (PFGE) and to compare these results to epidemiologic information, as well as examine the genetic diversity within and between the 25 other represented serovars of N gonorrhoeae.


METHODS
By PFGE, 237 N gonorrhoeae isolates were examined, and the results were compared with epidemiologic data for the IB-2 and IB-3 isolates.


RESULTS
In 79% of the domestic IB-2 cases involving homosexuals and 66% of the domestic IB-3 cases involving young heterosexuals, the isolates were genetically indistinguishable by PFGE. A high genetic diversity was identified within and between the 27 included serovars.


CONCLUSIONS
Examination by means of PFGE indicated that one N gonorrhoeae clone each of the serovars IB-2 and IB-3 created the majority of the two core groups of domestic cases.
Unemo
Magnus
M
National Reference Laboratory for Pathogenic Neisseria and Unit for Infectious Disease Control, Department of Clinical Microbiology and Immunology, Orebro Medical Centre Hospital, Orebro, Sweden. magnus.unemo@orebroll.se
Berglund
Torsten
T
OlcEn
Per
P
Fredlund
Hans
H
D004269:DNA, Bacterial / Q000032:analysis*; D016521:Electrophoresis, Gel, Pulsed-Field; D006069:Gonorrhea / Q000453:epidemiology* / Q000382:microbiology; D020010:Heterosexuality; D006716:Homosexuality; D006801:Humans; D009344:Neisseria gonorrhoeae / Q000235:genetics* / Q000302:isolation & purification; D015995:Prevalence; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology
D004269:DNA, Bacterial