Data from: Azithromycin-resistant Neisseria gonorrhoeae isolates in Guangzhou, China (2009–2013): coevolution with decreased susceptibilities to ceftriaxone and genetic characteristics

Background: The recent emergence of azithromycin-resistant (AZM-R) N.
gonorrhoeae isolates that have coevolved decreased susceptibility to
extended-spectrum cephalosporins has caused great concern. Here we
investigated the prevalence of decreased susceptibility to ceftriaxone
(CROD) in AZM-R isolates and genetically characterized AZM-R isolates in
Guangzhou, China from 2009 to 2013. Methods: The minimum inhibitory
concentration (MIC) of AZM and ceftriaxone was determined using an
agar-dilution method. All AZM-R isolates were screened for mutations in
23S rRNA, mtrR and penA genes and genotyped using N. gonorrhoeae
multi-antigen sequence typing (NG-MAST). Results: Of the 485 identified N.
gonorrhoeae isolates, 445 (91.8%) were isolated from male urethritis
subjects, and 77 (15.9%) were AZM-R (MIC ≥ 1 mg/L), including 33 (6.8%)
with AZM low-level resistant (AZM-LLR, MIC = 1 mg/L) and 44 (9.1%) with
AZM middle-level resistant (AZM-MLR, MIC ≥ 2 mg/L). Significantly more
CROD (MIC ≥ 0.125 mg/L) showed in AZM-MLR isolates (43.2%, 19/44) as
compared with that in AZM-LLR isolates (18.2%, 6/33) (p < 0.05).
For the 23S rRNA, mtrR, penA or combined 23S rRNA/MtrR/penA mutations, no
significant difference was found between AZM-LLR isolates and AZM-MLR
isolates (P > 0.05); similar results were detected between combined
AZM-LLR/CROD isolates and combined AZM-MLR/CROD isolates (P >
0.05). No mutation A2059G or AZM high-level resistant (AZM-HLR, MIC ≥ 256
mg/L) isolate was detected. Among 77 AZM-R isolates, 67 sequence types
(STs) were identified by NG-MAST, of which 30 were novel. Most STs were
represented by a single isolate. Conclusions: The AZM-R together CROD
isolates are now present in Guangzhou, China, which deserve continuous
surveillance and the mechanism of concurrent resistance needs further
study.