Antimicrobial Susceptibility Testing Patterns of Neisseria gonorrhoeae from Patients Attending Sexually Transmitted Infections Clinics in Six Regions in Tanzania

Abstract

Antimicrobial resistance (AMR) is global health threat that is on the increase, and it has been adversely affecting the proper management of sexually transmitted infections (STI). Data on antimicrobial susceptibility testing patterns of N. gonorrhoeae are limited in local settings. We determined in vitro antimicrobial susceptibility and phenotypic profiles of N. gonorrhoeae isolated from STI/Outpatient Department (OPD) clinics. Minimum Inhibitory Concentrations (MIC) (µg/mL) were determined using E-Test and agar dilution methods for previously and currently recommended antimicrobial agents. A total of 164 N. gonorrhoeae isolates from urethral discharge and endocervical swabs were tested. The prevalence of resistant N. gonorrhoeae to tetracycline, norfloxacin, penicillin and ciprofloxacin were 98.6%, 82.2%, 84.3% and 75.6%, respectively. None of the isolates was resistant to kanamycin. Penicillinase producing N. gonorrhoeae (PPNG) was found to be 73.7%, with 56.7% and 43.3% observed among isolates from women and men, respectively. Tetracycline resistant-N. gonorrhoeae (TRNG) was found to be 34.0%, and QRNG with HLR to ciprofloxacin was 79.9%. The overall MDR-NG was 79.9%, and XDR-NG was 3.6%. MIC50 and MIC90 were 4.0 and 8.0 and 2.0 and 4.0 µg/mL for ciprofloxacin and norfloxacin, respectively. Dendrograms showed that 44 phenotypic groups are associated with a high rate of AMR among high MDR-NG and moderate XDR-NG isolates. The predominant groups of quinolone-resistant N. gonorrhoeae (QRNG)+PPNG (34.7%) and QRNG+PPNG+TRNG (32.9%) were observed among the isolates having HLR to ciprofloxacin. We reported a high prevalence of AMR (>90%) to previously recommended antimicrobials used for the treatment of gonorrhoea. Multidrug resistant N. gonorrhoeae (MDR-NG) was highly reported, and extensively drug resistant (XDR-NG) has gradually increased to the currently recommended cephalosporins including ceftriaxone and cefixime. Heterogeneous groups of QRNG+PPNG+ and QRNG+PPNG+TRNG were highly resistant to penicillin, tetracycline, ciprofloxacin and norfloxacin. A surveillance program is imperative in the country to curb the spread of AMR.