Investigating the cause of increased tetracycline-resistant Neisseria gonorrhoeae in England, 2016-20

Abstract

Background: Antimicrobial resistance in Neisseria gonorrhoeae is a global public health concern. Tetracycline resistance (TetR) increased from 39.4% to 75.2% between 2016 and 2021 in N. gonorrhoeae isolates collected through national surveillance in England, despite the absence of use of tetracyclines for the treatment of gonorrhoea.

Objectives: We investigated whether there was correlation between bacterial sexually transmitted infection (STI) tests performed and treatment with antimicrobials, with increased TetR in N. gonorrhoeae.

Methods: We examined correlations between bacterial STI tests, antimicrobial treatment and TetR in N. gonorrhoeae, using national surveillance data from three large sexual health services (SHS) in London during 2016-20. Doxycycline prescribing data and antibiograms of a non-STI pathogen from distinct patient groups (sexual health, obstetric and paediatric), at a large London hospital, were analysed to identify if doxycycline use in SHS was associated with resistance in a non-STI organism.

Results: A substantial increase in TetR was observed, particularly in isolates from gay, bisexual and other MSM (GBMSM). Strong positive correlations were observed exclusively in GBMSM between N. gonorrhoeae TetR and both bacterial STI tests (r = 0.97, P = 0.01) and antimicrobial treatment (r = 0.87, P = 0.05). Doxycycline prescribing increased dramatically during the study period in SHS. Prevalence of TetR in Staphylococcus aureus was higher in isolates sourced from SHS attendees than those from other settings.

Conclusions: Frequent screening of GBMSM at higher risk of STIs, such as those on pre-exposure prophylaxis (PrEP) leading to/and increased use of doxycycline for the treatment of diagnosed infections, may account for the increase in TetR in N. gonorrhoeae.

Figure 1.

Trends in bacterial STI tests, treatment with antimicrobials and tetracycline-resistant N. gonorrhoeae at Chelsea and Westminster SHSs, between 2015 and 2019, by sexual risk (a–c). *Episode of care during which at least one test for chlamydia, gonorrhoea, syphilis and/or M. genitalium was carried out. To avoid double-counting, only one test is counted within a 42 day episode of care. †Episode of care during which antimicrobial(s) were prescribed. Derived as a composite measure of (i) being diagnosed with and treated with antimicrobials for a bacterial STI (chlamydia, gonorrhoea, syphilis, LGV, M. genitalium) or non-specific genital infection OR (ii) being given antimicrobial treatment as a contact of someone diagnosed with one of the following: chlamydia, gonorrhoea, syphilis, non-specific genital infection, PID, M. genitalium. To avoid double-counting, only one diagnosis or treatment respectively is counted within a 42 day episode of care. Tetracycline resistance is defined as an MIC > 1 mg/L (EUCAST breakpoint) and stratified by low-level tetracycline resistance (MIC = 2 to 8 mg/L) and high-level tetracycline resistance (MIC > 8 mg/L). Independent variables (e.g. bacterial STI tests, antimicrobials prescribed) compared with dependent variable (proportion of gonococcal isolates resistant to tetracycline) in the following year, e.g. bacterial STI tests in 2015 compared with % resistant in 2016. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.

Figure 1.

Trends in bacterial STI tests, treatment with antimicrobials and tetracycline-resistant N. gonorrhoeae at Chelsea and Westminster SHSs, between 2015 and 2019, by sexual risk (a–c). *Episode of care during which at least one test for chlamydia, gonorrhoea, syphilis and/or M. genitalium was carried out. To avoid double-counting, only one test is counted within a 42 day episode of care. †Episode of care during which antimicrobial(s) were prescribed. Derived as a composite measure of (i) being diagnosed with and treated with antimicrobials for a bacterial STI (chlamydia, gonorrhoea, syphilis, LGV, M. genitalium) or non-specific genital infection OR (ii) being given antimicrobial treatment as a contact of someone diagnosed with one of the following: chlamydia, gonorrhoea, syphilis, non-specific genital infection, PID, M. genitalium. To avoid double-counting, only one diagnosis or treatment respectively is counted within a 42 day episode of care. Tetracycline resistance is defined as an MIC > 1 mg/L (EUCAST breakpoint) and stratified by low-level tetracycline resistance (MIC = 2 to 8 mg/L) and high-level tetracycline resistance (MIC > 8 mg/L). Independent variables (e.g. bacterial STI tests, antimicrobials prescribed) compared with dependent variable (proportion of gonococcal isolates resistant to tetracycline) in the following year, e.g. bacterial STI tests in 2015 compared with % resistant in 2016. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.