Research and analysis

GRASP report: data to September 2025

Updated 13 November 2025

Applies to England and Wales

Main findings

One ceftriaxone-resistant Neisseria (N.) gonorrhoeae isolate was detected in the sentinel surveillance programme for the first time in 2024. This isolate was also detected in real-time through direct referral of suspected ceftriaxone-resistant isolates to the UK Health Security Agency (UKHSA) Sexually Transmitted Infections Reference Laboratory (STIRL). This case was associated with travel to the Asia Pacific region.

Through referral of resistant isolates outside of the sentinel surveillance system, 15 cases of ceftriaxone resistance have been detected in the first 8 months of 2025, exceeding the total number detected for the whole of 2024 (n=13). Most cases continue to be associated with travel to the Asia Pacific region.

Most gonococcal isolates remain highly susceptible to ceftriaxone. Although the percentage of isolates with reduced susceptibility to ceftriaxone (minimum inhibitory concentration (MIC) >0.03 mg/L) remains low at 1.7%, it has increased consecutively since 2021.

Cefixime resistance decreased from 5.6% in 2023 to 3.1% in 2024. Reduced susceptibility to both ceftriaxone (MIC >0.03 mg/L) and cefixime (MIC >0.06 mg/L) was associated with the presence of mosaic or semi-mosaic penA alleles, with penA-34 accounting for 88% of mosaic alleles overall.

Reduced susceptibility to azithromycin (epidemiological cut-off value (ECOFF) >1 mg/L) was 13.6%; however, 90% of isolates with reduced susceptibility had an azithromycin MIC of 2 mg/L, immediately above the ECOFF.

Nearly all isolates (90.7%) were considered resistant to tetracycline (MIC >0.5 mg/L). A quarter of isolates (25.9%) were resistant to penicillin (MIC >1 mg/L), nearly double that recorded in the previous year. Ciprofloxacin susceptibility was predicted from genomic data in 2024, and resistance decreased from 58.6% in 2023 to 46.4% in 2024.

Multilocus sequence typing (MLST) results provided insights into the underlying gonococcal population structure. The top 10 sequence types (STs) accounted for 68.8% of the isolates, which was comparable to 2022 to 2023; however, shifts in the composition and relative proportions of the top 10 STs were identified. Common STs differed in their patterns of antimicrobial susceptibility, and fluctuations in their prevalence will have contributed to changes in overall resistance.

Prescribing data demonstrated excellent adherence to the UK guideline for managing infection with N. gonorrhoeae, with 97.0% of individuals receiving the recommended first-line of ceftriaxone 1g intramuscular (IM) monotherapy in 2024.

Recommendations

All primary diagnostic laboratories should test gonococcal isolates for susceptibility to ceftriaxone, the current recommended first-line therapy for gonorrhoea (1g IM monotherapy) in the UK.

Suspected ceftriaxone-resistant isolates (MIC >0.125 mg/L, European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoint) should be referred to the UKHSA STIRL for confirmatory testing and follow-up.

Possible cases of ceftriaxone treatment failure should be reported to UKHSA via the HIV and STI Data Exchange (access is restricted to registered users).

Healthcare practitioners should ensure that all individuals diagnosed with gonorrhoea are treated and managed according to national guidelines.

In August 2025, England introduced the 4CMenB (Bexsero) vaccination programme for gonorrhoea prevention. The vaccine should be offered primarily to gay, bisexual and other men who have sex with men (GBMSM) at increased risk of gonorrhoea (those with a bacterial STI in the previous 12 months or reporting 5 or more sexual partners in the previous 3 months).

Introduction

Gonorrhoea, caused by the bacterium Neisseria gonorrhoeae, is the second-most diagnosed STI in England. If untreated, gonorrhoea can lead to complications including chronic pelvic pain, pelvic inflammatory disease, ectopic pregnancy, epididymitis, prostatitis, and urethral strictures.

Gonorrhoea diagnoses in England are high, with 71,802 cases reported in 2024. This is, however, a 16% decrease relative to 2023, when the largest annual number of cases was reported (85,370) since records began in 1918. The 2024 decrease was seen across gender and sexual orientation groups; however, this decrease was most prominent among women (34% decrease), followed by heterosexual men (18% decrease) and GBMSM (4% decrease). Diagnosis rates of gonorrhoea remained highest among specific population groups: GBMSM, young people aged 20 to 34 years, and individuals of Black Caribbean and Mixed ethnicities.

Ceftriaxone is an extended-spectrum cephalosporin (ESC) that is currently recommended in the UK as the first-line therapy for gonorrhoea (1g IM monotherapy). ESCs are among the few licensed antimicrobials that can be effectively used as first-line monotherapy for gonorrhoea.

Ongoing monitoring of antimicrobial resistance (AMR), comprising the culture of isolates, test-of-cure (TOC) and ongoing comprehensive and enhanced surveillance, is vital to detect emerging trends and to ensure that first-line treatments for gonorrhoea remain effective. Ineffective treatment facilitates onward transmission of infections and resistant strains, and the development of sequelae.

This report presents trends in gonococcal susceptibility to currently- and historically-used antimicrobials and explores the recent epidemiology and genomic characteristics of N. gonorrhoeae AMR in England and Wales. GRASP includes a suite of surveillance systems to detect and monitor AMR in N. gonorrhoeae and to record potential treatment failures; these include the GRASP sentinel surveillance system, referrals to STIRL and reports of suspected treatment failures.

GRASP 2024 methodology changes

Due to a technical issue reported with the previous medium used for antimicrobial susceptibility testing (AST), a decision was made to change the medium for testing 2024 GRASP isolates. A full validation of the new medium was carried out; this included testing of 6 WHO control strains and confirmed improved performance. Systematic shifts between the previous and new media were observed for MICs of azithromycin, cefixime and penicillin, therefore changes in prevalence of resistance to these agents may be under- or over-estimated due to inaccurate estimates in previous years. For further details, please see Appendix 1.

Mutations encoding ciprofloxacin resistance are well-defined, and phenotypic testing for ciprofloxacin susceptibility was therefore replaced with genotypic testing in 2024. Prediction of ciprofloxacin resistance is now based on detection of mutations in gyrA that result in amino acid substitutions at codon 91. Further details are available in the Supplementary information on ciprofloxacin resistance prediction.

The GRASP sentinel surveillance system

GRASP sentinel surveillance data is obtained annually from a network of 26 sexual health services (SHSs) across England and Wales and their associated laboratories. The number of participating services can vary between annual collections. In 2024, 22 SHSs (20 in England, 2 in Wales) and 18 laboratories participated in the programme. The geographical distribution of the 26 routinely participating SHSs is shown in Figure 1.

Participating laboratories are requested to collect consecutive N. gonorrhoeae isolates during August and September. All collected N. gonorrhoeae isolates are sent to STIRL for antimicrobial susceptibility testing. Antimicrobial susceptibility results are linked securely to the pseudonymised GUMCAD STI Surveillance System data to obtain demographic and clinical details. GUMCAD is a disaggregated, patient-level data set of all STI tests and diagnoses at SHSs in England. Supplementary demographic, clinical and behavioural data is submitted by participating SHSs to enhance GUMCAD data.

Two-sample tests of proportion and Chi-square tests for trend are used to define recent and longitudinal antimicrobial susceptibility trends, respectively. Isolates underwent whole-genome sequencing (WGS) to define the population structure and understand the molecular basis of resistance to antimicrobials (Appendix 2).

Full details on the data sets and methodology used for the GRASP sentinel surveillance system are available in the GRASP protocol.

Figure 1. Map showing 26 sentinel sexual health services participating in GRASP across UKHSA regions in England, Wales and local authorities in London (shown at larger scale), 2024

Source: Data from GRASP sentinel surveillance system.

STI reference laboratory

As part of standard referral criteria, all primary diagnostic laboratories in England are requested to submit all N. gonorrhoeae isolates with suspected ceftriaxone resistance (MIC >0.125 mg/L, EUCAST breakpoint) to STIRL for species confirmation and antimicrobial susceptibility testing. These isolates are tested by bioMérieux ETEST on GCVIT medium and are not subject to the medium change described in Appendix 1.

Referral criteria is restricted to suspected ceftriaxone resistance as resistance to other, non-first-line antimicrobials is prevalent and does not warrant public health follow-up.

Treatment failures

Information on suspected ceftriaxone treatment failures in England is reported to UKHSA via the HIV and STI Data Exchange (access is restricted to registered users).

Sentinel surveillance sample

Sampling frame

The 2024 GRASP collection took place between 1 August and 30 September 2024. Figure 2 shows that, during this period, 5,921 gonorrhoea diagnoses were reported to GUMCAD by the 20 English SHSs participating in GRASP in 2024. Over the same period, 2,137 N. gonorrhoeae isolates were sent to STIRL for antimicrobial susceptibility testing from these SHSs (2,243 isolates including Welsh clinics).

Isolates were included in analyses if they:

• could be case-matched to a participating GRASP SHS within the GUMCAD STI Surveillance System (n=1,655)
• had been successfully tested for susceptibility to 5 antimicrobials (azithromycin, cefixime, ceftriaxone, penicillin and tetracycline) (n=1,512)

As of 2024, ciprofloxacin susceptibility was predicted based on genotype for isolates for which WGS data was obtained (n=1,482).

Figure 2. Sentinel surveillance sampling frame flowchart in GRASP 2024

Source: Data from GRASP sentinel surveillance system.

Where more than one isolate was collected from an individual, a hierarchy for testing was applied as shown in Table 1. Of note, since 2021, pharyngeal isolates are prioritised ahead of all other sites due to concerns that resistance is most likely to emerge at this site. In 2020 and prior years, pharyngeal isolates were included within ‘any other site’ and were only tested if isolates from rectal, urethral or cervical sites were unavailable. Among the 1,512 tested and case-matched isolates in 2024, the anatomical site of specimen collection was most commonly urethral (41.9%), followed by rectal (31.6%) and pharyngeal (17.3%). In comparison, pharyngeal isolates constituted only 7.7% of those included in the 2020 GRASP sample.

Table 1. Anatomical site of specimen collection hierarchy and percentage of all isolates within respective GRASP collections, 2020 to 2024

Site of specimen collection	2020 N=1,531	2021 N=1,459	2022 N=1,460	2023 N=1,762	2024 N=1,512
Pharyngeal (highest priority)	118 (7.7%)	294 (20.2%)	301 (20.6%)	369 (20.9%)	262 (17.3%)
Rectal	415 (27.1%)	354 (24.3%)	379 (26.0%)	534 (30.3%)	478 (31.6%)
Urethral	718 (46.9%)	633 (43.4%)	594 (40.7%)	669 (38.0%)	633 (41.9%)
Cervical (including vaginal)	232 (15.2%)	150 (10.3%)	172 (11.8%)	171 (9.7%)	121 (8.0%)
Any other site (lowest priority) [note 1]	48 (3.1%)	28 (1.9%)	14 (1.0%)	19 (1.1%)	18 (1.2%)

Source: Data from GRASP sentinel surveillance system.

Note 1: ‘Any other site’ includes ocular, unknown sites of specimen collections and any other sites not listed.

Sentinel surveillance sample characteristics

Among 1,512 individuals with an N. gonorrhoeae isolate included in the sentinel surveillance sample, 87.4% were male, of whom 73.5% (971 out of 1,321) were GBMSM (Table 2a). Most individuals in the sentinel surveillance sample were White (58.8%) followed by individuals of Black ethnicity (11.2%) and Asian ethnicity (8.3%) (see ethnic categories in Appendix 4). The modal age group was 25 to 34 years (43.1%), with ages ranging from 15 to 78 years. Just over half (55.2%) were resident in London. Among all individuals, 10.4% were living with HIV, and 87.4% (132 out of 151) of these were GBMSM. One-fifth (20.4%) had been previously diagnosed with gonorrhoea in the past year and 18.1% were diagnosed with chlamydia at the same time as the gonorrhoea diagnosis considered within the GRASP analysis (Table 2b).

Data on HIV pre-exposure prophylaxis (PrEP) use at the time of gonorrhoea diagnosis and use of STI prophylaxis in the 3 months prior to gonorrhoea diagnosis was collected for the first time in GRASP 2024. HIV PrEP use in HIV-negative individuals was most common in GBMSM, with 79.1% reporting HIV PrEP use at the time of gonorrhoea diagnosis (Table 2b). Data on STI prophylaxis use in the previous 3 months was only available for 4.5% (n=68) of individuals, of whom 9 (13.2%) reported using doxycycline as STI prophylaxis in the 3 months prior to gonorrhoea diagnosis; all 9 individuals identified as GBMSM. No other antibiotics were reported to be used as STI prophylaxis.

Most individuals reported having either 0 to 1 (36.8%) or 2 to 5 (47.8%) sexual partners in the 3 months prior to their gonorrhoea diagnosis. Where data on the number of sexual partners abroad was reported (34.2%), a small proportion (8.9%) of individuals reported having a sexual partner abroad (outside of the UK) in the same time interval (Table 2c). Almost three-quarters (72.6%) of individuals were reported to have received a TOC, a higher proportion compared with 63.6% of individuals in 2023.

When the demographics of individuals included in the GRASP sentinel sample were compared with the demographics of those with a gonorrhoea diagnosis made at SHSs in the GUMCAD surveillance system over the same period (August to September 2024), women were under-represented in GRASP (11.9% versus 17.9%, probability (p) value <0.001), while GBMSM (64.2% versus 57.4%, p<0.001) and heterosexual men (19.0% versus 16.1%, p=0.004) were over-represented. London residents were also over-represented in the GRASP sentinel system relative to all diagnoses nationally (55.2% versus 46.5%, p<0.001).

Table 2a. Site of infection and symptom status of individuals in GRASP, by gender and sexual orientation, 2024 [note 2]

Characteristics	GBMSM	Heterosexual men	Women	Other and not reported [note 3]	Total
Metric	n (% of N) [note 4]	n (% of N) [note 4]	n (% of N) [note 4]	n (% of N) [note 4]	n (% of N) [note 4]
Number of individuals (N)	971	288	180	73	1,512
Site of infection: genital [note 5]	466 (48.0%)	269 (93.4%)	153 (85.0%)	39 (53.4%)	927 (61.3%)
Site of infection: rectal [note 5]	684 (70.4%)	12 (4.2%)	35 (19.4%)	43 (58.9%)	774 (51.2%)
Site of infection: pharyngeal [note 5]	477 (49.1%)	32 (11.1%)	64 (35.6%)	40 (54.8%)	613 (40.5%)
Site of infection: other [note 5]	26 (2.7%)	51 (17.7%)	2 (1.1%)	3 (4.1%)	82 (5.4%)
Site of infection: multiple sites [note 5]	526 (54.2%)	72 (25.0%)	64 (35.6%)	40 (54.8%)	702 (46.4%)
Symptoms: no	530 (54.8%)	44 (15.3%)	64 (36.2%)	32 (43.8%)	670 (44.5%)
Symptoms: yes	437 (45.2%)	243 (84.7%)	113 (63.8%)	41 (56.2%)	834 (55.5%)
Symptom: not reported [note 3]	4	1	3	0	8

Source: Data from GRASP sentinel surveillance system.

Note 2: gender and sexual orientation are self-reported. ‘Other and not reported’ includes 10 individuals who were gender diverse, as numbers were too few to analyse separately.

Note 3: ‘Not reported’ refers to instances where information was unknown or not stated.

Note 4: ‘N’ refers to all individuals in GRASP 2024 data set (by gender and sexual orientation) that have reported data for each characteristic and excludes individuals where data was not reported.

Note 5: numerator: individuals in GRASP 2024 data set infected at site specified (by gender and sexual orientation). Sites of infection are not mutually exclusive; individuals can have infections at multiple sites.

Denominator: all individuals in GRASP 2024 data set (by gender and sexual orientation) that have reported sites of infection. Not all individuals are tested for gonorrhoea at each site.

Percentages do not add up to 100% as individuals can be infected at more than one site. Please note that these numbers differ to isolates tested by specimen site as only one site is tested per individual.

For individuals with multiple sites of infection, the isolate tested followed the hierarchy described above.

Table 2b. Concurrent STI, previous gonorrhoea diagnosis and HIV PrEP use of individuals in GRASP, by gender and sexual orientation, 2024 [note 6]

Characteristics	GBMSM	Heterosexual men	Women	Other and not reported [note 7]	Total
Metric	n (% of N) [note 8]	n (% of N) [note 8]	n (% of N) [note 8]	n (% of N) [note 8]	n (% of N) [note 8]
Number of individuals (N)	971	288	180	73	1,512
Any concurrent STI: chlamydia [note 9]	189 (19.5%)	39 (13.5%)	29 (16.1%)	17 (23.3%)	274 (18.1%)
Any concurrent STI: other STIs [note 9]	70 (7.2%)	15 (5.2%)	3 (1.7%)	3 (4.1%)	91 (6.0%)
Previously diagnosed with gonorrhoea (past year): no	656 (73.2%)	209 (92.5%)	126 (94.7%)	64 (90.1%)	1,055 (79.6%)
Previously diagnosed with gonorrhoea (past year): yes	240 (26.8%)	17 (7.5%)	7 (5.3%)	7 (9.9%)	271 (20.4%)
Previously diagnosed with gonorrhoea (past year): not reported [note 7]	75	62	47	2	186
HIV PrEP use at time of gonorrhoea diagnosis: no [note 10]	156 (20.9%)	237 (97.5%)	146 (98.0%)	17 (30.4%)	556 (46.5%)
HIV PrEP use at time of gonorrhoea diagnosis: yes [note 10]	592 (79.1%)	6 (2.5%)	3 (2.0%)	39 (69.6%)	640 (53.5%)
HIV PrEP use at time of gonorrhoea diagnosis: not reported [note 7][note 10]	93	41	24	10	168

Source: Data from GRASP sentinel surveillance system.

Note 6: gender and sexual orientation are self-reported. ‘Other and not reported’ includes 10 individuals who reported they were gender diverse, as numbers were too few to analyse separately.

Note 7: ‘Not reported’ refers to instances where information was unknown or not stated.

Note 8: ‘N’ refers to all individuals in GRASP 2024 data set (by gender and sexual orientation) that have reported data for each characteristic and excludes all individuals where data was not reported.

Note 9: numerator: individuals in GRASP 2024 data set with any diagnosed concurrent STI (by gender and sexual orientation).

Denominator: all individuals in GRASP 2024 data set (by gender and sexual orientation that have reported answers for concurrent STIs. Not all individuals are tested for each STI.

Note 10: denominator excludes individuals with a positive HIV diagnosis prior to gonorrhoea diagnosis.

Table 2c. Number of partners and reporting of sex abroad of individuals in GRASP, by gender and sexual orientation, 2024 [note 11]

Characteristics	GBMSM	Heterosexual men	Women	Other and not reported [note 12]	Total
Metric	n (% of N) [note 13]	n (% of N) [note 13]	n (% of N) [note 13]	n (% of N) [note 13]	n (% of N) [note 13]
Number of individuals (N)	971	288	180	73	1,512
Total sexual partners (past 3 months): 0 to 1	206 (24.1%)	152 (57.8%)	121 (72.5%)	18 (28.6%)	497 (36.8%)
Total sexual partners (past 3 months): 2 to 5	470 (54.9%)	99 (37.6%)	40 (24.0%)	36 (57.1%)	645 (47.8%)
Total sexual partners (past 3 months): 6 to 10	111 (13.0%)	5 (1.9%)	4 (2.4%)	5 (7.9%)	125 (9.3%)
Total sexual partners (past 3 months): 11 and over	69 (8.1%)	7 (2.7%)	2 (1.2%)	4 (6.3%)	82 (6.1%)
Total sexual partners (past 3 months): not reported [note 12]	115	25	13	10	163
Sex abroad (past 3 months): no	207 (89.2%)	156 (91.8%)	93 (93.9%)	15 (93.8%)	471 (91.1%)
Sex abroad (past 3 months): yes	25 (10.8%)	14 (8.2%)	6 (6.1%)	1 (6.3%)	46 (8.9%)
Sex abroad (past 3 months): not reported [note 12]	739	118	81	57	995

Source: Data from GRASP sentinel surveillance system.

Note 11: gender and sexual orientation are self-reported. ‘Other and not reported’ includes 10 individuals who reported they were gender diverse, as numbers were too few to analyse separately.

Note 12: ‘Not reported’ refers to instances where information was unknown or not stated.

Note 13: ‘N’ refers to all individuals in GRASP 2024 data set (by gender and sexual orientation) that have reported data for each characteristic and excludes all individuals where data was not reported.

Whole genome sequencing

The integration of WGS into GRASP provides insights into the N. gonorrhoeae lineages that are driving AMR trends and makes it possible to monitor changes in lineages over time. Additionally, WGS facilitates the identification of molecular determinants of AMR and the prediction of antimicrobial susceptibility phenotype from genotype. Isolates were submitted for WGS (Appendix 2), with genomes for 1,482 of 1,512 (98.0%) isolates meeting internal quality criteria.

Molecular typing

Two molecular typing schemes commonly used to describe N. gonorrhoeae sequence types (STs) are:

• MLST: catalogues variation in fragments of 7 housekeeping genes
• N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR): catalogues variation in 7 chromosomal genes associated with antimicrobial resistance

The nucleotide sequences comprising these typing schemes can be obtained from WGS data, which allows comparisons with previous GRASP years, other laboratories, and published data. In 2024, complete MLST profiles were obtained for all analysed genomes, corresponding to 1,482 out of 1,512 (98.0%) isolates. Complete NG-STAR profiles were obtained for all but 2 genomes, equating to 1,480 out of 1,512 (97.9%) isolates overall.

There were 94 unique MLST STs in 2024, which was comparable to 2022 (n=92) and 2023 (n=94). The 10 most common STs accounted for 1,020 out of 1,482 (68.8%) isolates, which was similar to 2022 (69.1%) and 2023 (67.9%). In contrast, 75 STs were each observed in ≤1.0% of isolates, 38 of which were identified in only a single isolate.

The top 10 STs from 2024 were compared with those from 2022 and 2023, highlighting changes in the frequency of predominant STs between 2023 and 2024 (Figure 3). The most common STs in 2024 were ST8134 (13.5%, ranked eighth in 2023), ST16676 (12.6%, ranked sixth in 2023), and ST7822 (8.8%, ranked second in 2023). The greatest increases were observed for ST8134 (+9.6%), ST16676 (+8.4%), and ST13292 (+3.8%, ranked 19th in 2023). The largest decreases were for ST1580 (−7.9%, ranked first in 2023), ST9362 (−6.4%, ranked fourth in 2023), and ST10314 (−3.9%, ranked fifth in 2023).

With respect to the NG-STAR scheme, there were 214 STs in 2024, the most common of which were ST3735 (170 out of 1,480, 11.5%), ST4668 (107 out of 1,480, 7.2%), and ST1969 (74 out of 1,480, 5.0%). Typing schemes such as MLST and NG-STAR can be used in combination to provide greater resolution. The combination of MLST ST8134 and NG-STAR ST3735 was predominant overall in 2024 (170 out of 1,480, 11.5%), comprising 170 out of 200 (85.0%) MLST ST8134 isolates. Isolates with MLST ST8134 and NG-STAR ST3735 were not detected in 2022 and accounted for only 33.3% of ST8134 isolates in 2023, suggesting this lineage may have undergone recent clonal expansion.

Several major MLST STs were associated with multiple NG-STAR STs, some of which would be predicted to have distinct AMR profiles. For instance, the second most frequent MLST ST16676 corresponded to 5 NG-STAR STs in 2024, with NG-STAR ST4668 and ST5567 predominating (56.1% and 31.6% of MLST ST16676 isolates, respectively). Similarly, MLST ST7822 corresponded to 5 NG-STAR STs in 2024, with NG-STAR ST1969 accounting for the majority (56.1%) followed by ST5728 (29.2%).

Figure 3. Distribution of predominant MLST STs in 2024 compared with 2022 and 2023 [note 14]

Source: Data from GRASP sentinel surveillance system.

Note 14: STs that ranked in the top 10 in at least one year (2022 to 2024) are shown. STs are ordered based on rank abundance in 2024.

Antimicrobial resistance

N. gonorrhoeae has developed resistance to all classes of antimicrobials recommended to treat gonorrhoea. Table 3 shows the AMR definitions used in GRASP. Antimicrobial susceptibility results were interpreted using current EUCAST breakpoints. Figure 4 and Table 4 show trends in the percentage of gonococcal isolates, collected through the GRASP sentinel surveillance system, resistant to selected antimicrobials since a previous change in the testing medium (2015 to 2024) then with a focus on more recent trends (2020 to 2024).

Trends for tetracycline are presented from 2022 onwards following the update in resistance breakpoint from 1 mg/L to 0.5 mg/L. Breakpoint plates at 0.5 mg/L were introduced in 2022; therefore, no data for this breakpoint is available prior to 2022. Full trend data from 2000 can be found in Appendix 3. Antimicrobial susceptibility results were also analysed in conjunction with MLST STs to explore lineage-associated patterns in AMR (Figure 5).

Antimicrobial susceptibility testing for gentamicin has been paused for the current year and susceptibility will only be monitored intermittently. No resistance breakpoint for gentamicin has been established and previous data has shown that the modal MIC remains low. Spectinomycin AST has been stopped as spectinomycin is no longer available in the UK.

Table 3. Antimicrobial resistance definitions

Antimicrobial	MIC breakpoint for resistance (mg/L)
Ceftriaxone	>0.125
Azithromycin [note 15]	>1
High-level azithromycin [note 16]	≥256
Cefixime	>0.125
Ciprofloxacin	>0.06
Penicillin	>1 and/or beta-lactamase positive
Tetracycline	>0.5

Source: Definitions from EUCAST.

Note 15: until 2018, EUCAST had set a breakpoint of MIC 0.5 mg/L for N. gonorrhoeae azithromycin resistance. This has since been replaced with an ECOFF of 1 mg/L. The previous breakpoint of 0.5 mg/L shown in previous GRASP reports is no longer retained as a historic reference point.

Note 16: high-level azithromycin resistance is not defined by EUCAST, but the definition of ≥256 mg/L is internationally recognised.

Figure 4. Percentage of N. gonorrhoeae isolates in GRASP that were resistant to selected antimicrobials, England and Wales, 2015 to 2024 [note 17]

Source: Data from GRASP sentinel surveillance system.

Note 17: due to changes to the medium used to test antimicrobial susceptibility of sentinel surveillance isolates, MICs for the 2024 collection should be interpreted with caution when compared to previous years (Appendix 1). Point of change in AST medium is indicated by the vertical dashed black line.

Azithromycin data for 2023 has not been presented due to a laboratory technical issue as indicated by the break in the trend line.

In 2023, EUCAST updated the resistance breakpoint for tetracycline against N. gonorrhoeae from 1 mg/L to 0.5 mg/L. Breakpoint plates at 0.5 mg/L were introduced in 2022; therefore, no data for this breakpoint is available prior to 2022.

Ciprofloxacin resistance in 2024 was predicted using a subset of data where whole-genome sequencing results were available (n=1,482).

Figure 5. Resistance to selected antimicrobials across the top 20 MLST STs in GRASP, 2024 [note 18]

Source: Data from GRASP sentinel surveillance system.

Note 18: data is shown for the top 20 MLST STs identified in 2024, comprising 1,281 out of 1,512 (84.7%) isolates overall.

Values in each row indicate the percentage of isolates from a given MLST ST with mosaic or semi-mosaic penA alleles, phenotypic resistance to key antimicrobials, and predicted resistance to ciprofloxacin based on WGS.

Isolate counts and percentage (of isolates with WGS data) are shown in round brackets after the ST, followed by percentage change relative to 2023 in square brackets.

Table 4. Number and percentage of N. gonorrhoeae isolates in GRASP that were resistant to selected antimicrobials, England and Wales, 2020 to 2024 [note 19]

Antimicrobial MIC resistance breakpoint (mg/L)	2020 N=1,531	2021 N=1,459	2022 N=1,460	2023 N=1,763	2024 N=1,512
Ceftriaxone (>0.125)	0 (0.0%)	0 (0.0%)	0 (0.0%)	0 (0.0%)	1 (0.1%)
Azithromycin (>1) [note 20]	64 (4.2%)	74 (5.1%)	99 (6.8%)	Not applicable	206 (13.6%)
Cefixime (>0.125)	9 (0.6%)	4 (0.3%)	11 (0.8%)	99 (5.6%)	47 (3.1%)
Ciprofloxacin (>0.06) [note 21]	677 (44.2%)	683 (46.8%)	855 (58.6%)	1,034 (58.7%)	687 (46.4%)
Penicillin (>1) or beta-lactamase positive	145 (9.5%)	207 (14.2%)	198 (13.6%)	251 (14.2%)	391 (25.9%)
Tetracycline (>0.5) [note 22]	Not applicable	Not applicable	1,228 (84.1%)	1,425 (80.8%)	1,371 (90.6%)

Source: Data from GRASP sentinel surveillance system.

Note 19: due to changes to the medium used to test antimicrobial susceptibility of sentinel surveillance isolates, MICs for the 2024 collection should be interpreted with caution when compared to previous years (Appendix 1).

Note 20: azithromycin data for 2023 has not been presented due to a laboratory technical issue.

Note 21: ciprofloxacin resistance in 2024 was predicted using a subset of data where whole-genome sequencing results were available (n=1,482).

Note 22: in 2023, EUCAST updated the resistance breakpoint for tetracycline against N. gonorrhoeae from 1 mg/L to 0.5 mg/L. Breakpoint plates at 0.5 mg/L were introduced in 2022; therefore, no data for this breakpoint is available prior to 2022.

Ceftriaxone

Sentinel surveillance system sample

Among 1,512 isolates included in the sentinel surveillance sample in 2024, one was resistant to ceftriaxone (MIC >0.125 mg/L) with an MIC of 0.5 mg/L (Table 4). This individual case was associated with travel to the Asia Pacific region where ceftriaxone resistance is more common/prevalent. The proportion of isolates with reduced susceptibility (defined here as an MIC >0.03 mg/L) to ceftriaxone increased from 0.9% (16 out of 1,762) in 2023 to 1.7% (25 out of 1,512) in 2024 (p=0.01) (Figure 6).

Figure 6. Percentage of N. gonorrhoeae isolates in GRASP with reduced susceptibility to ceftriaxone (MIC >0.03 mg/L), England and Wales, 2015 to 2024 [note 23]

Source: Data from GRASP sentinel surveillance system.

Note 23: reduced susceptibility to ceftriaxone is defined here as MICs >0.03 mg/L.

Despite a slight increase in isolates with a MIC >0.03 mg/L, there was a continued shift towards more susceptible MICs (≤0.004 and 0.008 mg/L) since 2023. The modal MIC was 0.008 mg/L both overall (Figure 7) and across all gender and sexual orientation groups (Figure 8). The proportion of isolates with a MIC >0.03 mg/L in heterosexual men (2.4%) and women (1.7%) remained similar to that seen in GBMSM (1.3%).

Figure 7. Distribution of ceftriaxone MICs (mg/L) for N. gonorrhoeae isolates in GRASP, England and Wales, 2015 to 2024

Source: Data from GRASP sentinel surveillance system.

Figure 8. Distribution of ceftriaxone MICs (mg/L) for N. gonorrhoeae isolates in GRASP, by gender and sexual orientation, England and Wales, 2024

Source: Data from GRASP sentinel surveillance system.

Molecular determinants of resistance

Penicillin-binding protein 2 (PBP2) is the primary target of ESCs and is encoded by the penA gene. Alterations in penA are the primary molecular mechanism of reduced susceptibility or resistance to ESCs, and variation in the gene arises through point mutations and recombination with other Neisseria species. penA allele numbering (for example penA-34) originated from historical PBP2 types defined based on 82 key amino acid sites, while nucleotide variation is captured as a decimal (for example penA-34.001).

Mosaic penA alleles arise through recombination and contain 60 to 70 amino acid substitutions compared with wild-type N. gonorrhoeae PBP2. Mosaic alleles such as penA-10 and penA-34 have been associated with reduced ESC susceptibility, while penA-60 and penA-237 have emerged among ceftriaxone-resistant strains. Semi-mosaic alleles contain smaller recombinant fragments, typically altering only the first or second half of the gene. Non-mosaic alleles lack recombinant fragments, but may still contain amino acid substitutions that can contribute to reduced ESC susceptibility in combination with other resistance determinants, such as over-expression of the MtrCDE efflux pump and alterations in PonA and PorB.

In 2024, penA alleles were assigned for 1,481 out of 1,482 (99.9%) isolates with WGS data. There were 26 penA types and 38 variants, which was comparable to 2022 and 2023. A total of 1,182 (79.8%), 269 (18.2%), and 30 (2.0%) isolates carried non-mosaic, mosaic, and semi-mosaic penA alleles, respectively. There was a small increase in the percentage of mosaic alleles compared with 2023 (14.7% to 18.2%) and a corresponding decrease in semi-mosaic alleles (5.7% to 2.0%) (Figure 9).

Mosaic and semi-mosaic alleles were associated with reduced ceftriaxone susceptibility (MIC >0.03 mg/L) in 2024. Overall, 14 out of 299 (4.7%) of isolates with either mosaic or semi-mosaic penA alleles had elevated ceftriaxone MICs (>0.03 mg/L) compared to 8 out of 1,182 (0.7%) isolates with non-mosaic alleles (odds ratio (OR) 7.21, p<0.001).

The single ceftriaxone-resistant isolate carried the mosaic allele penA-237.001 and corresponded to MLST ST1901 and NG-STAR ST4837 (the only instance of this combination in GRASP 2024). The remaining mosaic alleles mainly corresponded to penA-34 (239 out of 269, 88.8%). Most semi-mosaic alleles corresponded to penA-93 (26 out of 30, 86.7%), while penA-2 (446 out of 1,182, 37.7%), penA-14 (357 out of 1,182, 30.2%), and penA-5 (205 out of 1,182, 17.3%) were the most frequent non-mosaic types.

Comparison of the most common mosaic and semi-mosaic alleles between 2022 and 2024 indicated that types have largely remained stable, except for a small decrease in penA-93 (−3.6%) and increase in penA-166 (+1.0%) between 2023 and 2024. At the variant level, penA-34.007 overtook penA-34.001 to become the predominant mosaic variant. Mosaic and semi-mosaic penA alleles were dispersed across 26 MLST STs; however, they were concentrated in major lineages such as ST16676, ST1580, ST8123, and ST7363, accounting for 34.8% to 95.8% of isolates in each (Figure 5).

Figure 9. Distribution of penA mosaic classifications by year, 2022 to 2024

Source: Data from GRASP sentinel surveillance system.

Direct referrals to STIRL

Outside of GRASP sentinel surveillance, the reference service in STIRL conducts confirmatory testing of suspected ceftriaxone-resistant N. gonorrhoeae isolates identified by primary diagnostic laboratories, to provide real-time individual clinical reports that guide patient care. Through this service, there were 15 ceftriaxone-resistant N. gonorrhoeae cases confirmed via direct referral to STIRL in the first 8 months of 2025. Further information on ceftriaxone-resistant cases identified in England via direct referrals can be found online.

Cefixime

Cefixime-resistant (MIC >0.125 mg/L) isolates decreased from 5.6% in 2023 to 3.1% in 2024 (p=0.001) (Figure 4, Table 4). However, cefixime resistance in 2024 remained higher than estimates between 2015 to 2022, which ranged from 0.3 to 2.2%.

In 2024, the modal MIC was 0.015 mg/L overall (Figure 10) and across all gender and sexual orientation groups (Figure 11). The proportions of isolates resistant to cefixime (MIC >0.125 mg/L) among GBMSM (2.8%) and heterosexual men (3.1%) were found to be significantly lower than among women (4.4%) (p<0.001 and p=0.004, respectively).

Figure 10. Distribution of cefixime MICs (mg/L) for N. gonorrhoeae isolates in GRASP, England and Wales, 2015 to 2024

Source: Data from GRASP sentinel surveillance system.

Note 24: due to changes to the medium used to test antimicrobial susceptibility of sentinel surveillance isolates, MICs for the 2024 collection should be interpreted with caution when compared to previous years (Appendix 1).

Figure 11. Distribution of cefixime MICs (mg/L) for N. gonorrhoeae isolates in GRASP, by gender and sexual orientation, England and Wales, 2024

Source: Data from GRASP sentinel surveillance system.

Molecular determinants of resistance

As observed for ceftriaxone, mosaic and semi-mosaic penA alleles were associated with reduced cefixime susceptibility (MIC >0.06 mg/L) in 2024. Overall, cefixime MICs were elevated for 265 out of 299 (88.6%) isolates with either mosaic or semi-mosaic penA alleles compared with only 14 out of 1,168 (1.2%) isolates with non-mosaic alleles (OR=650.25, p<0.0001).

WGS data was available for 45 out of 47 (95.7%) cefixime-resistant isolates, all but 2 of which carried mosaic penA alleles. The predominant variants were penA-34.007 (20 out of 45, 44.4%) and penA-34.001 (16 out of 45, 35.5%). All 45 cefixime-resistant isolates with WGS data also had ceftriaxone MICs that were greater than the mode (0.008 mg/L), ranging from 0.03 mg/L to 0.5 mg/L. Cefixime-resistant isolates were dispersed across 14 MLST STs but were most common in ST1580 (20.5%) and ST1583 (23.5%) (Figure 5).

Azithromycin

Resistance breakpoints for azithromycin were removed by EUCAST in 2019 and replaced with an ECOFF of 1 mg/L (Table 3). The modal MIC in GRASP 2024 was 1 mg/L, at the ECOFF (Figure 12).

There were 202 isolates (13.6%) with azithromycin MICs above the ECOFF (>1 mg/L). Of these, most had an MIC of 2 mg/L. Only 21 isolates had MICs >2 mg/L and 4 isolates (0.3%) had MICs >256 mg/L, an internationally recognised measure of high-level azithromycin resistance. This was a decrease from 0.9% (16 isolates) with MICs >256 mg/L in 2023.

The modal azithromycin MIC for isolates from GBMSM was 2 doubling dilutions higher than among heterosexual men and women (1 mg/L vs 0.25 mg/L vs 0.25 mg/L) (Figure 13). Isolates with azithromycin MICs above the ECOFF were identified in 22 MLST STs. The percentage of isolates with MICs greater than the ECOFF varied among the top 20 MLST STs, ranging from 1.1% to 66.7% (Figure 5).

Figure 12. Distribution of azithromycin MICs (mg/L) for N. gonorrhoeae isolates in GRASP, England and Wales, 2015 to 2024

Source: Data from GRASP sentinel surveillance system.

Note 25: azithromycin data for 2023 has not been presented due to a laboratory technical issue.

Note 26: due to changes to the medium used to test antimicrobial susceptibility of sentinel surveillance isolates, MICs for the 2024 collection should be interpreted with caution when compared to previous years (Appendix 1).

Figure 13. Distribution of azithromycin MICs (mg/L) for N. gonorrhoeae isolates in GRASP, by gender and sexual orientation, England and Wales, 2024

Tetracycline, penicillin and ciprofloxacin

There was an increase in tetracycline resistance from 80.1% in 2023 to 90.7% in 2024 (p<0.001) (Figure 4). Tetracycline resistance was identified in 79 MLST STs in 2024. Resistance ranged from 89% to 100% across the top 20 MLST lineages, except for ST1580 (66.3%), ST8156 (30.0%), and ST7359 (0.0%) (Figure 5). Of the 2024 isolates, 30.1% were high-level tetracycline resistant (MIC >8 mg/L). High-level tetracycline resistance was detected in 35 MLST STs and was particularly common among major lineages such as ST16676 (94.1%), ST7363 (87.3%), and ST8123 (95.8%).

The proportion of isolates resistant to penicillin increased from 14.2% in 2023 to 25.9% in 2024 (p<0.001), which is the highest prevalence of penicillin resistance to date. Penicillin resistance has fluctuated but remained relatively stable between 9.5% and 17.9% from 2015 to 2023 (Figure 4). Penicillin resistance was observed across 33 MLST STs; however, most (85.7%) resistant isolates were concentrated in 5 STs, including ST16676 (92.5%), ST7363 (87.3%), ST8123 (97.9%), ST1583 (64.7%), and ST1587 (96.3%) (Figure 5). With the exception of ST1583, all of these STs increased in prevalence between 2023 and 2024, contributing to the rise in penicillin resistance observed in 2024.

In 2024, ciprofloxacin resistance was inferred from WGS data based on the amino acid predicted at GyrA codon 91 (see Supplementary information on ciprofloxacin resistance prediction). Three amino acids were detected at GyrA codon 91: serine (GyrA S91, 46.4%, wildtype), phenylalanine (GyrA S91F, 53.6%, non-wildtype, predicted resistant), and threonine (GyrA S91T, 0.1%, non-wildtype, confirmed susceptible by ETEST (MIC 0.004 mg/L)). The GyrA S91T substitution had not been detected previously in GRASP; therefore, the full length gyrA allele was queried against PubMLST, where it was found in 2 N. gonorrhoeae and 616 N. meningitidis genomes.

Overall, there was a 12.2% decrease in predicted ciprofloxacin resistance compared with 2023 (58.6% to 46.4%, p<0.001). The observed decrease corresponded with fluctuations in major MLST lineages (Figure 5). ST8134 isolates became predominant in 2024, all but one of which were predicted to be susceptible to ciprofloxacin. The second most common lineage, ST16676, was variably susceptible (60%) and had also increased in frequency, as had several other variably or uniformly susceptible lineages. Ciprofloxacin resistance was predicted in 63 MLST STs. This included all representatives of the major lineages ST7822, ST7363, ST8123, and ST9362, which together accounted for 19.8% of all isolates with WGS data (Figure 5).

Prescribing practices

Antimicrobial prescribing data was reported for 1,584 individuals diagnosed with gonorrhoea at SHSs participating in GRASP in 2024, irrespective of whether a N. gonorrhoeae isolate was available for antimicrobial susceptibility testing.

Of these, 97.0% (1,537 out of 1,584) received ceftriaxone (1g IM), in accordance with BASHH first-line treatment recommendations; this proportion was similar for GBMSM (97.6%) and heterosexual men (97.5%), but was lower for women (93.3%, p=0.002). The remaining 47 individuals were prescribed second-line treatments. Of these, 18 received cefixime and azithromycin, 16 received gentamicin and azithromycin, 11 received azithromycin 2g monotherapy and 2 received ciprofloxacin 500mg.

Discussion

In 2024, one case of ceftriaxone resistance (MIC >0.125 mg/L) was detected in the sentinel surveillance programme – the first since surveillance began in 2000. This case was also identified in real-time at the local laboratory and directly referred to STIRL for confirmation as per UKHSA guidance. Investigations in real-time confirmed that the infection was associated with travel from the Asia Pacific region, where ceftriaxone resistance is widespread. The isolate carried the mosaic penA-237.001 allele and belonged to MLST ST1901, a combination previously described among international ceftriaxone-resistant isolates.

The frequency of ceftriaxone-resistant cases reported to STIRL, outside of the GRASP sentinel surveillance programme, has continued to increase. Cases reported thus far in 2025 have exceeded the total reported in 2024, which had been the highest to date. 8 out of 15 cases in 2025 were also extensively drug-resistant (XDR) with resistance to both first- and second-line treatment options and to other antibiotics. Most cases were linked to acquisition of infection in the Asia-Pacific region. However, as some cases appear to have acquired infection within the UK and as not all partners could be contacted, undetected transmission within England is possible.

Due to the rarity of ceftriaxone-resistant isolates in GRASP, reduced susceptibility to ceftriaxone (MIC >0.03 mg/L) is monitored, as there may be an increase at this threshold before MICs cross the breakpoint for resistance. The increase in reduced susceptibility to ceftriaxone was subtle but has increased successively from 0.2% in 2021 to 1.7% in 2024.

Cefixime is an ESC recommended in the UK as an alternative treatment regimen for gonorrhoea (together with azithromycin) if IM treatment is contraindicated or refused. Cefixime resistance decreased from 5.6% in 2023 to 3.1% in 2024. This decrease is likely in part due to the change in medium for susceptibility testing (Appendix 1). However, the major ST most correlated with cefixime resistance, ST1580, decreased during this period, which may indicate a true decrease due to fewer circulating strains harbouring cefixime resistance.

Mosaic penA alleles were over-represented among cefixime-resistant isolates, and reduced susceptibility to ceftriaxone and cefixime was associated with the presence of mosaic or semi-mosaic penA alleles. Mosaic and semi-mosaic penA alleles were most commonly observed in a subset of predominant MLST STs, as in previous years.

The change in medium also impacted MICs of azithromycin, resulting in a large increase in isolates with reduced susceptibility to azithromycin (ECOFF >1 mg/L). This increase, from 6.8% in 2022 to 13.6% in 2024, is likely due to under-estimation in 2022. The modal MIC has also increased by 2 doubling dilutions to 1 mg/L. The difference in MIC distribution between sexual orientations is prominent, as the modal MIC for GBMSM was two doubling dilutions higher than that of heterosexual men and women.

Tetracycline resistance was high with 90.6% of isolates considered resistant. High-level tetracycline resistance (MIC >8 mg/L) is also prevalent at 30.1%. Consequently, doxycycline post-exposure prophylaxis (doxyPEP) is unlikely to reduce gonorrhoea incidence in England. Data on STI prophylaxis use was limited, but where reported, showed that 13.2% (9 out of 68) of individuals with a gonorrhoea diagnosis had used doxycycline as STI prophylaxis in the last 3 months, all of whom identified as GBMSM.

Molecular typing information extracted from WGS data provided insights into the underlying gonococcal population structure. Although 94 MLST STs were identified, the top 10 STs accounted for 68.8% of isolates. Comparisons of predominant STs between 2022 and 2024 identified fluctuations in the composition and relative proportions of the top 10 STs. Common STs differed in their patterns of antimicrobial susceptibility and variation in lineage prevalence will have contributed to the observed changes in overall resistance to key antimicrobials.

Prescribing data collected through the sentinel surveillance system demonstrates 100% compliance with UK guidelines, with nearly all individuals receiving the recommended first-line therapy of ceftriaxone 1g IM monotherapy.

Treatment failure to ceftriaxone 1g is rare in the UK, even in cases with phenotypic ceftriaxone resistance (MIC >0.125 mg/L). Four cases of treatment failure have been confirmed to date in England (1 in 2015, 2 in 2018 and 1 in 2024). Both cases in 2018 were cleared with 3 days of ertapenem (1g IV) after unsuccessful treatment with ceftriaxone (1g IM), while the 2024 case was cleared with a single dose of ertapenem (1g IV) following unsuccessful treatment with both ceftriaxone (1g IM) and separately azithromycin (2g orally). All documented treatment failures occurred at extragenital sites of infection (3 pharyngeal, 1 rectal). Health practitioners are encouraged to continue reporting all possible cases of ceftriaxone treatment failure to UKHSA via the HIV and STI Data Exchange (access is restricted to registered users).

The 4CMenB (Bexsero) vaccination programme for gonorrhoea commenced in England in August 2025. It is possible that the vaccination programme will reduce resistance levels by reducing infection rates and hence antibiotic use. 4CMenB may be more effective against some strains of N. gonorrhoeae while less effective against others. This is further complicated by the yearly fluctuations of predominant STs that have been observed in GRASP. Going forward, the GRASP surveillance programme will be an invaluable resource to monitor the impact of this new immunisation programme on gonococcal infection, molecular epidemiology and AMR.

Conclusions

The detection of the first case of ceftriaxone resistance in the sentinel surveillance programme sample is not surprising given the increasing number of cases detected outside of GRASP. However, surveillance indicates that most N. gonorrhoeae infections remain highly susceptible to ceftriaxone and 1g ceftriaxone continues to be effective. Health practitioners, microbiologists and public health authorities should be alert for suspected ceftriaxone resistance, as spread of these strains in highly dense networks is a foreseeable threat to the effectiveness of ceftriaxone.

Cefixime and azithromycin resistance levels are concerning and may have implications for their use as second-line treatments in the future. Most isolates were resistant to tetracycline, which will limit the effectiveness of doxyPEP on gonorrhoea incidence.

A high level of vigilance is required to facilitate the timely detection of emerging trends in resistance and ensure the continued effectiveness of first-line treatments. Culture and antimicrobial susceptibility testing of isolates, test of cure, and notification and management of sexual partners remain vital. Continued strong adherence to treatment guidelines and referral of isolates to STIRL for confirmatory antimicrobial susceptibility testing, where isolates are locally identified to be ceftriaxone-resistant, are also essential.

Appendices

Appendix 1. Interpretation of MIC changes in the context of media change

Main implications of GRASP 2024 Media Change from HDST to GCVIT

The extensive validation work carried out at STIRL on stored GRASP isolates has shown the following critical differences when switching from HIMEDIA diagnostic sensitivity test agar (HDST) to GC agar base (Difco GC medium base, BD) plus 1% Vitox (GCVIT):

Table 5. Observations and inferred impact of switching from HDST to GCVIT on GRASP isolates, 2024

Observation	Impact on GRASP 2024 isolates
Azithromycin MICs are ≥1 doubling dilution higher for over 70% of isolates on GCVIT medium, but are more accurate than the MICs on HDST.	The increase in proportion of resistant isolates may partly be due to underestimation on HDST in previous years.
Cefixime MICs of approximately one-third of isolates are one doubling dilution lower on GCVIT medium, whereas only approximately 10% are ≥1 doubling dilution higher.	The decrease in resistance may partly be due to overestimation on HDST in previous years.
Penicillin resistance is reported more commonly on GCVIT medium.	The increase in resistance may partly be due to underestimation of resistance on HDST.
There were no notable differences for the MICs or categoric SIR result for ceftriaxone or tetracycline.	There is no impact on resistance trends for ceftriaxone or tetracycline.

Historical Changes in GRASP Media and Drivers for Change

From 2000 until 2015, Oxoid diagnostic sensitivity test agar (ODST) supplemented with 5% defibrinated horse blood (TCS Biosciences, HB038) and 1% Vitox (Oxoid, SR0090H) was the medium utilized for AST in GRASP. In 2016, the media base was changed to HDST (plus supplements, as previously), because it was found to support the growth of a wider range of N. gonorrhoeae isolates. However, one limitation of this medium change was that for some antimicrobials (particularly cefixime and azithromycin) the HIMEDIA DST medium produced MICs for WHO control strains that varied by one doubling dilution to the reported MICs. Cefixime control strains were found to be one dilution higher and azithromycin strains were one dilution lower than expected.

In 2023, STIRL initiated a full media review and GCVIT was adopted as the most appropriate medium for GRASP 2024. GCVIT was selected as:

• it produced the expected results for the WHO control strains
• it is widely used by other global gonococcal AMR surveillance schemes therefore results should be more comparable

Appendix 2. Methods for WGS

Genomic DNA was extracted using the QIAGEN DSP DNA Mini or Midi kit with the Blood 400 protocol on the QIAsymphony. DNA yield was determined using the Quant-iT kit on the GloMax system. Genomic DNA was sent to the UKHSA Colindale Sequencing Laboratory where Illumina Nextera XT or DNA Prep libraries were generated and sequenced on the NextSeq 1000 platform.

Deplexed and trimmed reads (Trimmomatic) were run through an in-house bioinformatics pipeline to: confirm species identification and screen for contaminants (Kraken2); generate a de novo assembly (SPAdes) and assembly statistics (QUAST); determine MLST and NG-STAR, sequence types (in-house software); and detect known AMR determinants (in-house software and AMRFinderPlus). Novel typing alleles and profiles were submitted to the relevant public database for assignment by curators (PubMLST (MLST) and NG-STAR).

Appendix 3. Percentage of N. gonorrhoeae isolates resistant to selected antimicrobials from 2000 to 2024

Figure 14. Percentage of N. gonorrhoeae isolates in GRASP that were resistant to selected antimicrobials, England and Wales, 2000 to 2024 [note 27]

Source: Data from GRASP sentinel surveillance system.

Note 27: due to changes in the medium used to test antimicrobial susceptibility of sentinel surveillance isolates, MICs and trends from 2000 to 2014 compared with 2015 to 2023 must be interpreted with caution, particularly for azithromycin data. Further changes to the medium used to test antimicrobial susceptibility of sentinel surveillance isolates for GRASP 2024 mean that MICs for the 2024 collection must also be interpreted with caution compared to previous years (Appendix 1). Points of medium change are indicated by dashed vertical lines.

Azithromycin data for 2023 has not been presented due to a technical issue as indicated by the break in the trend line.

In 2023, EUCAST updated the resistance breakpoint for tetracycline against N. gonorrhoeae from 1 mg/L to 0.5 mg/L. Breakpoint plates at 0.5 mg/L were introduced in 2022; therefore, no data for this breakpoint is available prior to 2022 and trend data is not presented.

Ciprofloxacin resistance in 2024 was predicted using a subset of data where whole-genome sequencing results were available (n=1,482).

Appendix 4. Ethnic categories

The ethnic categories used in this report are as specified by the Office for National Statistics (ONS). Data are often presented by disaggregated ethnic groups among people of Black ethnicity to highlight the variability in rates among the ethnic group experiencing the highest rates of the most commonly diagnosed STIs. People of Asian, Mixed, Other and White ethnicity are presented as aggregated ethnic groups for comparison.

Acknowledgements 

GRASP would like to thank the collaborating centres and the advisory group for their continued support, SHSs for the prompt submission of clinical data and laboratories for sending isolates to UKHSA STIRL Colindale.

Advisory group (listed alphabetically)

R Browne, C Curtis, H Donaldson, C Ison, DM Livermore, S Palanivel, M Rayment, J Ross, T Sadiq, K Sibson, S Soni, K Templeton.

Collaborating centres

• Birmingham (H Ahmed, S Brown, R Chaudhry, D Ezeagu, E Glenister, M Hamad, J Phattey, J Ross, S Thomas, A Uddin)
• Bristol (S Brazier, M Griffin, N Rees, S Tanaka, M Williams, A Wolujewicz)
• Brighton (K Anderson, B Broster, T Casey, G Dean, C Fitzpatrick, C Fowler, G Jones, I Martin-Jorge, K Parker, C Reynolds, D Richardson, S Soni)
• Cardiff (L Davies, R Drayton, L Jones, J Richards)
• Chelsea and Westminster (A Bari, K Bide, N Chapman, I Clapp, A Colcutt, B Cookhorn, L Faulkner, J Greenham, J Hardie, G Jagjitsingh, N Jeyapalan, A Kufuor, I Lewis, A Lyons, I Mavropoulos, A Montaser, Z Nwaosu, E Peres, V Raina, C Scott, B Selwyn, T Silva Carvalho, G Von Schweitzer, G Whitlock)
• Gloucester (J Boyes, A Godwin, I Karunaratne, L Kear, J Lewis, J Nightingale, M Simon)
• Homerton (F Abbs, D Ball, P Horne, T Karadag, A Keirs, N Marshall, D Martin, N North, P Zachary, S Zetie)
• King’s College Hospital (S Bholah, E Drakes, M Brady, M Brown, T Kamvumbi, N Kaur, G MacMillan, C McDonald)
• Leeds (T Ahmad, S Birdi, I Cocking, D De Silva, A Evans, K Sibson, S Taylor)
• Liverpool (J Anson, C Brookfield, H Carney, E Clarke, A Elmer, G McCarthy, S Rajapakse)
• London Charring Cross (A Bari, H Donaldson, S Goonesekera, S Shah)
• Luton (K Zyla, J Turner, D Karim, S Jaise, R Mulla)
• Manchester (J Birtles, A Brooks, L Devine, S Flaherty, H Heapy, Z Jeffrey, A Qamruddin, E Sandham, A Sukthankar)
• Newport (C Barret, J Bendle, N Berry, Z Kempson, C Knapper)
• Northampton (B Alounti, E Chiriseri, E Haines, M Kelly, L Riddell)
• Nottingham (J Bowskill, J Deery, J Dengate, C Okafor, M Pammi, L Pillai)
• Sheffield (A Carr, C Dewsnap, R Matcham, C Megson, H Parsons, C Turnock)
• St Mary’s Hospital (R Dawson, O Dosekun, SHIP Team)
• Central and North West London (C Baker, R Browne, D Carta, J Choudhury, S Ellam, M Grayson, D Harkness, M Mansoor, L Matthews, M Nur, M Vasconcelos, H Vyse-White, R White)
• Wolverhampton (D Dobie, J Hudson, S Lovegrove, R McCathie, K Whitehouse)

Authors: Suzy Sun, Prarthana Narayanan, Melissa Jansen van Rensburg, Anna Vickers, Sandhya Vivekanand, Penny Cliff, Rachel Pitt, Sandra David, Ella Breese, Emma Callan, Michelle Cole, Hamish Mohammed, Katy Sinka, Sarah Alexander, Helen Fifer.

Suggested citation

Suzy Sun, Prarthana Narayanan, Melissa Jansen van Rensburg, Anna Vickers, Sandhya Vivekanand, Penelope Cliff, Rachel Pitt, Sandra David, Ella Breese, Emma Callan, Michelle Cole, Hamish Mohammed, Katy Sinka, Sarah Alexander, Helen Fifer. GRASP report: data to September 2025. November 2025, UK Health Security Agency, London