Susceptibility of Neisseria gonorrhoeae to azithromycin and ceftriaxone in China: A retrospective study of national surveillance data from 2013 to 2016.

BACKGROUND: Gonorrhea remains one of the most common sexually transmitted diseases worldwide. Successful treatment has been hampered by emerging resistance to each of the antibiotics recommended as first-line therapies. We retrospectively analyzed the susceptibility of gonorrhea to azithromycin and ceftriaxone using data from the China Gonococcal Resistance Surveillance Programme (China-GRSP) in order to provide evidence for updating the treatment recommendations in China. METHODS AND FINDINGS: In this study, we included 3,849 isolates collected from patients with a confirmed positive Neisseria gonorrhoeae (N. gonorrhoeae) culture at clinic visits during the period of 1 January 2013 through 31 December 2016 in 7 provinces. Antimicrobial susceptibility testing of gonorrhea isolates using agar dilution was conducted to determine minimum inhibitory concentration (MIC). Resistance to azithromycin (RTA) was defined as MIC ≥ 1.0 mg/l, and decreased susceptibility to ceftriaxone (DSC) was defined as MIC ≥ 0.125 mg/l. The prevalence of isolates with RTA was 18.6% (710/3,827; 95% CI 17.4%-19.8%). The percentage of patients with DSC fluctuated between 9.7% and 12.2% over this period. The overall prevalence of isolates with both RTA and DSC was 2.3% (87/3,827; 95% CI 1.9%-2.8%) and it increased from 1.9% in 2013 to 3.3% in 2016 (chi-squared test for trend, P = 0.03). Study limitations include the retrospective study design and potential biases in the sample, which may overrepresent men with symptomatic infection, coastal residents, and people reporting as heterosexual. CONCLUSIONS: To our knowledge, this is the first national study on susceptibility of N. gonorrhoeae to azithromycin and ceftriaxone in China. Our findings indicate high rates of RTA and DSC from 2013 to 2016. Although dual therapy with azithromycin and ceftriaxone has been recommended by WHO and many countries to treat gonorrhea, reevaluation of this therapy is needed prior to its introduction in China.

Surveillance of antimicrobial susceptibilities of Neisseria gonorrhoeae in Nanning, China, 2000 to 2012.

OBJECTIVES: To monitor the frequency of antibiotic resistance of Neisseria gonorrhoeae (NG) in Nanning, China, between 2000 and 2012. METHODS: The production of ß-lactamase by NG isolates was determined using the paper acidometric testing method. Antimicrobial susceptibility testing was performed for tetracycline, ciprofloxacin, spectinomycin, and ceftriaxone using the agar dilution method. The χ(2) test, t test, and univariate and multivariate analyses were used to analyze the statistical difference of the results. RESULTS: A total of 923 NG isolates were collected in Nanning between 2000 and 2012. Among these, 131 (14.2%) were penicillinase-producing NG, 520 (56.3%) isolates were tetracycline-resistant NG, and 857 (92.9%) isolates were ciprofloxacin-resistant strains. One spectinomycin-resistant strain was identified in 2000. There were 304 (32.9%) isolates with decreased susceptibility to ceftriaxone; the proportion of such isolates increased from 22.8% in 2000 to 2002 to 48.9% in 2006 to 2008 (P < 0.001), followed by a fall to 32.2% in 2009 to 2012 (P = 0.001). Patients' age of 16 to 25 years and isolate collection period of 2008 to 2012 (except 2011) were demonstrated to be risk factors for infection with isolates with decreased susceptibility to ceftriaxone. CONCLUSIONS: Antimicrobial susceptibility of NG isolates obtained from patients in Nanning from 2000 to 2012 was characterized by high occurrence of penicillinase-producing NG, tetracycline-resistant NG, and ciprofloxacin-resistant strains. Spectinomycin and ceftriaxone can be considered drugs of choice for empirical treatment of NG infection in Nanning. Moreover, we recommend a combination of 500 mg or higher dose of intramuscular ceftriaxone and 1 g oral azithromycin be used for the treatment of NG infection in Nanning and possibly in China.