Reduced susceptibility to azithromycin and high percentages of penicillin and tetracycline resistance in Neisseria gonorrhoeae isolates from Manaus, Brazil, 1998

Background: The identification of Neisseria gonorrhoeae isolates resistant to antimicrobial agents currently recommended for the treatment of gonococc al infections continues to escalate globally. Thus, in some areas, resistan ce to fluoroquinolone drugs is commonplace; several reports document resist ance to third-generation cephalosporins, and the sporadic isolation of spec tinomycin-resistant isolates continues unabated. Gonococcal resistance to a zithromycin, an antibiotic used for the primary treatment of gonococcal inf ections in some Latin American countries, also has been described. Because the prevalence of resistant isolates is insufficiently documented in many a reas of Latin America, the efficacy of locally recommended therapies for go nococcal infections is often unknown. Goal: To determine the antimicrobial susceptibility and strain types of N g onorrhoeae isolates collected in Manaus, Brazil. These data will establish antimicrobial susceptibility baseline data for the region as a reference po int for future surveillance. Study Design: Consecutive N gonorrhoeae isolates from urethral and endocerv ical specimens were collected and examined for identity, antimicrobial susc eptibility, and strain type (plasmid content, tetM type, auxotype, and sero var). Results: Most of the isolates (65/81; 85.2%) were resistant to tetracycline , penicillin, or both, with the majority (n = 62) carrying plasmid-mediated resistance to tetracycline (tetracycline-resistant N gonorrhoeae [TRNG]). All of the TRNG contained the Dutch-type tetM plasmid, and 18 were A/S clas s NR/IA-02. Penicillinase-producing N gonorrhoeae comprised 8.2% (7/81) of the isolates. Of these seven isolates, four also were TRNG, and two carried chromosomal resistance to tetracycline. The isolates were susceptible to c iprofloxacin, spectinomycin, and ceftriaxone. However, 23 isolates were cha racterized by reduced susceptibility to azithromycin (MIC, 0.25-0.5 mug/ml) , and one isolate had reduced susceptibility to ciprofloxacin (MIC, 0.25 mu g/ml). Conclusions: This study supports the continued use of third-generation ceph alosporins, spectinomycin, and fluoroquinolone drugs for the primary treatm ent of gonococcal infections in Manaus. The occurrence of isolates with red uced susceptibility to azithromycin and ciprofloxacin underscores the impor tance of ongoing antimicrobial susceptibility monitoring to support decisio ns regarding appropriate drugs for the treatment of gonococcal infections.