Antimicrobial resistance of Neisseria gonorrhoeae isolated from patients attending sexually transmitted infection clinics in Urban Hospitals, Lusaka, Zambia

Abstract

Background: Neisseria gonorrhoeae, the causative agent for sexually transmitted infection (STI) gonorrhoea, has emerged with a significant public health impact on acquiring resistance to antimicrobials available for treatment. The resistance of N. gonorrhoeae limit treatment options and contributed to high morbidity associated with gonorrhoea. Data on antimicrobial resistance (AMR) profiles in N. gonorrhoeae is scares in Zambia. This study aimed to determine the antibiotic susceptibilities in N. gonorrhoeae isolates from Lusaka, Zambia.

Methods: A prospective cross-sectional study was conducted on 630 STI patients who presented with urethral or vaginal discharge from 2019 to 2020. Urethral and endocervical secretions were cultured on Modified Thayer Martin agar and incubated at 36 °C ± 1 °C in 5% CO₂ for 24 h. Identification of N. gonorrhoeae isolates was achieved by Gram stain, oxidase, nitrocefin disk, BactiCard Neisseria, and Viteck® Compact. The AMR profiles were determined using E-test. Statistical significant was determined by Pearson's Chi-square test, Mann-Whitney U test, or logistic regression with p-values of < 0.05 indicating significance.

Results: A total of 630 patients were recruited of which 46% (290/630) with the median of 29 years and interquartile range (IQR) of 19-39 years were male. The median of the females was 26 years and IQR of 15-37 years. Neisseria gonorrhoeae was isolated from 19.4% (122/630) patients of which 72.9% (89/122) were male, with highest prevalence of isolation in the age category of 25-34 years. The prevalence of resistance was high to penicillin (85.2%), tetracycline (68.9%) and ciprofloxacin (59.8%) with MIC₉₀ of 32 µg/mL, 8 µg/mL, and 8 µg/mL respectively. The isolates had reduced susceptibility to cefixime (1.6%), spectinomycin (4.9%) and (4.9%) for azithromycin. All isolates were susceptible to ceftriaxone. Risk factors associated with AMR were douching in females (AOR 6.69, 95% CI; 1.11-40.31, p = 0.039), female gender (AOR 7.64, 95% CI; 1.11-52.33, p = 0.048), HIV-positivity (AOR 26.59, 95% CI; 3.67-192.7, p = 0.005), no condom use or unprotected sex (AOR 5.48, 95% CI; 1.17-22.75 p = 0.026), sex trading (AOR 4.19, 95% CI; 1.55-11.33, p = 0.010), and over-counter treatment of ciprofloxacin (AOR 3.44, 95% CI; 1.17-22.75, p = 0.023).

Conclusion: The N. gonorrhoeae resistance to penicillin, tetracycline and ciprofloxacin was high necessitating revision of the treatment guidelines. However, no resistance to ceftriaxone was detected. Therefore, monitoring of antibiotic resistance remains critical in Zambia.

Keywords: Antimicrobial resistance; Epsilometer test; Neisseria gonorrhoeae; Zambia.

Fig. 1

Distribution of age medians for participants with gonorrhoea

Fig. 2

MDR and XDR antibiotic combinations of AMR N. gonorrhoeae