Increasing resistance of Neisseria gonorrhoeae in west and central Africa. Consequence on therapy of gonococcal infection.
OBJECTIVE
Antimicrobial resistant strains of Neisseria gonorrhoeae have spread with remarkable rapidity in many African countries. Chromosomal resistance to penicillin, tetracycline, and thiamphenicol is frequent now, and reported prevalences of penicillinase-producing N. gonorrhoeae isolates vary between 15% and 80%. Plasmid-mediated tetracycline-resistant N. gonorrhoeae isolates have been observed in several African countries.


OBJECTIVE
To characterize gonococcal isolates from three sites in West and Central Africa, to determine antimicrobial susceptibility patterns, to document the spread of plasmid-mediated resistance to penicillin and tetracycline in these three sites, and to discuss the consequences of rising antimicrobial resistance on the management of gonococcal infection in Africa.


METHODS
Over time, a total of 2,288 gonococcal isolates were obtained from Abidjan, Ivory Coast (1992-1993, n = 251), from Kigali, Rwanda (1988-1993, n = 952), and from Kinshasa, Zaire (1988-1990, n = 1,085). The isolates were characterized by auxotyping and serotyping. Plasmid-mediated resistance to penicillin and to tetracycline was determined. Antimicrobial susceptibility testing to ceftriaxone, ciprofloxacin, penicillin, spectinomycin, tetracycline, and thiamphenicol was performed with an agar dilution method.


RESULTS
The prevalence of penicillinase-producing N. gonorrhoeae increased significantly over time from 44% to 57% in Kigali and remained stable at a high level in Abidjan (73%) and in Kinshasa (67%). The frequency of tetracycline-resistant N. gonorrhoeae increased significantly during the observation periods in all three sites: from 20% to 65% in Abidjan, from 0% to 64% in Kigali, and from 14% to 41% in Kinshasa. Chromosomal resistance to penicillin was common in Kigali and Kinshasa, and chromosomal resistance to tetracycline and thiamphenicol was frequent in all three sites. All gonococcal isolates were susceptible to ceftriaxone, ciprofloxacin, and spectinomycin. Prototrophic and proline requiring strains were predominant, and IA-6 was the most common serovar in the three sites. IB-specific serovars were more common among penicillinase-producing N. gonorrhoeae and IA-specific serovars were more frequent among tetracycline-resistant N. gonorrhoeae, but there was no evidence for a clonal spread of resistant strains.


CONCLUSIONS
This study illustrates the high frequency of resistant gonococci in Africa and shows that tetracycline-resistant N. gonorrhoeae have become highly endemic in different geographic areas of the continent. The use of effective drugs is essential to reduce gonorrhea transmission. Surveillance of temporal changes in antimicrobial resistance in gonococcal strain populations should be part of sexually transmitted diseases control programs.
Van Dyck
E
E
Institute of Tropical Medicine, Antwerp, Belgium.
Crabbé
F
F
Nzila
N
N
Bogaerts
J
J
Munyabikali
J P
JP
Ghys
P
P
Diallo
M
M
Laga
M
M
D007560:Cote d'Ivoire / Q000453:epidemiology; D015023:Democratic Republic of the Congo / Q000453:epidemiology; D004352:Drug Resistance, Microbial; D005260:Female; D006069:Gonorrhea / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D009344:Neisseria gonorrhoeae / Q000145:classification* / Q000235:genetics; D011159:Population Surveillance; D015995:Prevalence; D011815:R Factors; D012432:Rwanda / Q000453:epidemiology; D012703:Serotyping; D014504:Urban Health