Table 1.
Serogroup, PIP production and antimicrobial susceptibility/resistance phenotypes displayed by the 2024 WHO Neisseria gonorrhoeae reference strains (n = 15), which are relevant for susceptibility testing of current, previous and novel therapeutic antimicrobials
| Characteristics | WHO Fa | WHO H | WHO Ka | WHO La |
WHO Ma | WHO Oa | WHO Pa | WHO Q | WHO R | WHO S2 | WHO Ua | WHO Va | WHO Xa | WHO Ya | WHO Za |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NCTC number | 13 477 | 15 081 | 13 479 | 13 480 | 13 481 | 13 483 | 13 484 | 14 208 | 15 082 | 15 083 | 13 817 | 13 818 | 13 820 | 13 821 | 13 822 |
| Isolated (country, year) | Canada, 1991 | Austria, 2011 | Japan, 2003 | Asia, 1996 | Philippines, 1992 | Canada, 1991 | USA, Unknown | UK, 2018 | Japan, 2015 | Sweden, 2020 | Sweden, 2011 | Sweden, 2012 | Japan, 2009 | France, 2010 | Australia, 2013 |
| Serogroup | PorB1a | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b | PorB1b |
| PIP production | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | Pos | −b | Pos | Pos | Pos | Pos |
| β−lactamase (PPNG)c | — | — | — | — | Posc | Posc | — | — | Posc | — | — | Posc | — | — | — |
| Ampicillind,e | 0.032 | 2 | 2 | 2 | PPNGc (8) | PPNGc(32) | 0.064 | 2 | PPNGc (>256) |
0.25 | 0.125 | PPNGc (>256) |
2 | 0.5 | 2 |
| Azithromycind | S (0.25) | S (0.25) | S (0.5) | S (1) | S (0.5) | S (0.5) | R (4) | HLR (>256) | S (0.5) | R (2) | R (4) | HLR (>256) | S (0.5) | S (1) | S (1) |
| Aztreonamd,e | 0.016 | 8 | 4 | 2 | 0.125 | 0.5 | 0.125 | 64 | 32 | 0.064 | 0.064 | 0.25 | ≥256 | 64 | 32 |
| Cefepimed,e | <0.016 | 8 | 4 | 1 | 0.064 | 0.125 | 0.032 | 4 | 8 | 0.064 | 0.016 | 0.25 | 16 | 32 | 4 |
| Cefiximed | S (<0.016) | R (0.5) | LLR (0.25) | S (0.125) | S (<0.016) | S (0.016) | S (<0.016) | HLR (2) | HLR (1) | S (<0.016) | S (<0.016) | S (<0.016) | HLR (4) | HLR (2) | HLR (2) |
| Ceftarolined,e | 0.004 | 0.5 | 0.125 | 0.5 | 0.064 | 0.25 | 0.064 | 0.5 | 0.5 | 0.064 | 0.016 | 0.25 | 2 | 4 | 0.5 |
| Ceftriaxoned | S (<0.002) | LLR (0.25) | S (0.064) | LLR (0.25) | S (0.016) | S (0.032) | S (0.004) | R (0.5) | R (0.5) | S (0.008) | S (0.002) | S (0.064) | HLR (2) | HLR (1) | R (0.5) |
| Cefuroximed,e | 0.032 | 32 | 16 | 8 | 0.25 | 1 | 0.125 | 16 | 16 | 0.25 | 0.064 | 2 | 16 | 16 | 16 |
| Chloramphenicold,e | 0.5 | 8 | 4 | 8 | 4 | 4 | 4 | 8 | 8 | 1 | 4 | 8 | 8 | 4 | 8 |
| Ciprofloxacind | S (0.004) | HLR (>32) | HLR (>32) | HLR (>32) | R (2) | S (0.008) | S (0.004) | HLR (>32) | HLR (>32) | S (0.032) | S (0.004) | HLR (>32) | HLR (>32) | HLR (>32) | HLR (>32) |
| Ertapenemd,e | <0.002 | 0.064 | 0.064 | 0.032 | 0.016 | 0.016 | 0.004 | 0.032 | 0.016 | 0.004 | 0.004 | 0.008 | 0.064 | 0.008 | 0.016 |
| Erythromycind,e | 0.5 | 2 | 1 | 2 | 1 | 1 | 4 | >256 | 2 | 8 | >256 | >256 | 2 | 2 | 4 |
| Fosfomycind,e | 32 | 32 | 16 | 8 | 32 | 32 | 32 | 16 | 32 | 8 | 32 | 16 | 16 | 16 | 16 |
| Gentamicind,e | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 8 | 4 | 8 | 4 | 8 | 4 |
| Gepotidacind,e | 0.125 | 0.5 | 0.5 | 4 | 2 | 0.5 | 0.5 | 1 | 0.25 | 1 | 0.25 | 0.25 | 0.5 | 0.5 | 0.5 |
| Kanamycind,e | 16 | 16 | 16 | 32 | 16 | 16 | 16 | 16 | 16 | 16 | 8 | 16 | 16 | 16 | 8 |
| Lefamulind,e | 0.125 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | 2 | 0.5 | 0.5 | 1 | 0.5 | 2 | 0.5 | 0.5 | 0.5 |
| Moxifloxacind,e | 0.004 | 4 | 8 | >32 | 1 | 0.016 | 0.032 | 2 | 8 | 0.064 | 0.008 | 8 | 8 | 4 | 8 |
| Penicillin Gd | S (0.032) |
R (2) |
R (2) |
R (2) |
PPNGc (≥32) | PPNGc (>32) | I (0.25) |
I (1) |
PPNGc (>32) |
I (0.5) |
I (0.125) |
PPNGc (>32) |
R (4) |
I (1) |
R (2) |
| Rifampicind,e | 0.125 | 0.5 | 0.5 | 0.5 | >32 | 0.25 | >32 | 0.5 | >32 | 0.5 | 0.25 | 0.5 | 0.5 | 0.5 | 0.5 |
| Spectinomycind | S (16) | S (8) | S (16) | S (16) | S (16) | R (>1024) | S (8) | S (8) | S (8) | S (16) | S (8) | S (16) | S (16) | S (16) | S (16) |
| Temocillind,e | 0.064 | 8 | 16 | 4 | 1 | 4 | 1 | 8 | 8 | 1 | 0.5 | 4 | 32 | 8 | 8 |
| Tetracyclined | S (0.25) | R (4) | R (2) | R (2) | R (2) | R (2) | R (1) | TRNG (128) | R (4) | R (2) | R (1) | R (4) | R (2) | R (4) | R (4) |
| Trimethoprim-Sulfamethoxazoled,e | 1 | 2 | 4 | 1 | 2 | 4 | 4 | 8 | 4 | 4 | 1 | 4 | 1 | 1 | 4 |
| Zoliflodacind,e | 0.064 | 0.064 | 0.125 | 0.125 | 0.064 | 0.125 | 0.25 | 0.032 | 0.064 | 0.25 | 0.064 | 0.125 | 0.064 | 0.125 | 0.125 |
National Collection of Type Cultures (NCTC) susceptible; I, susceptible, increased exposure; R, resistant; PPNG, penicillinase-producing N. gonorrhoeae; LLR, low-level resistant; HLR, high-level resistant; TRNG, plasmid-mediated high-level tetracycline resistant N. gonorrhoeae.
aInclude some previously published results.35 However, additional antimicrobials have been examined and some consensus MICs have slightly changed when additional MIC determinations using different MIC-determining methodologies have been performed.
bDo not produce the enzyme prolyliminopeptidase (PIP), which can result in doubtful and/or false-negative species identification of N. gonorrhoeae using biochemical or enzyme-substrate test. Global transmission of PIP-negative N. gonorrhoeae strains has been documented.45
cPPNG, penicillinase-producing N. gonorrhoeae (always considered resistant to all penicillins independent on identified MIC value, which might slightly vary).
dResistance phenotypes based on MIC (mg/L) using Etest and agar dilution (zoliflodacin, gepotidacin, lefamulin), and clinical susceptibility/resistance breakpoints stated by the EUCAST (v.14.0; https://www.eucast.org/clinical_breakpoints), where available. The reported MIC values are mean MICs (rounded to whole MIC doubling dilution) and the acceptable range of the MICs for each antimicrobial and the different strains is ±1 MIC doubling dilution. Note: the consensus MICs shown should be used and interpreted with caution because these were derived using one Etest method only and, consequently, may slightly differ using other methods.
eNo susceptibility/resistance breakpoints stated by the EUCAST (v.14.0; https://www.eucast.org/clinical_breakpoints).