Table 1 The principal groups of rPBP3 in Haemophilus influenzae with their associated amino acid substitutions and susceptibility to ampicillin. The clinical breakpoint for ampicillin is definied as R > 1 mg/L by EUCAST, which means that a subset of NTHi with rPBP3 genotype are still categorized as susceptible. Table modified after Skaare et al. [7]
From: A novel PBP3 substitution in Haemophilus influenzae confers reduced aminopenicillin susceptibility
Main rPBP3 group | Subgroup according to Skaare [7] | Key amino acid substitutions | Associated substitutions in subgroups | MIC range of Ampicillin (mg/L) | |
|---|---|---|---|---|---|
Group I | R517H | 0.5–2 [5] | |||
Group II | N526K | 0.5–8 [5] | |||
A | IIb | N526K | D350N M377I A502V V547I N569S | ||
B | IId | N526K | I449V V547I N569S | ||
C | IIb | N526K | D350N M377I G490E A502V V547I N569S | ||
D | II- | N526K | D350N G490E A530S | ||
E | IIc | N526K | A502T | ||
F | IIa | N526K | – | ||
G | II- | N526K | V547I A554T A561E N569S | ||
Group III | S385T + N526K | 1–32 [4] | |||
Group III-like | S385T + R517H | 0.5–2 [5] |