Table 3.
Mechanisms of β-lactam antimicrobial resistance among invasive H. influenzae strains (2014–2019). Amino acid substitutions in PBP3 and classification according to Dabernat et al. [25], and β-lactamase production
|
No. isolates |
MIC (mg l−1) |
Amino acid substitutions |
β-lactamase* |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
AMP |
AMC† |
Ile |
Asp |
Ala |
Met |
Ala |
Ile |
Gly |
Ala |
Asn |
Ala |
bla TEM-1 |
bla ROB-1 |
||
|
348 |
350 |
368 |
377 |
437 |
449 |
490 |
502 |
526 |
530 |
||||||
|
No changes |
32 |
≤0.12–0.25 |
≤0.5 |
|
|
− |
− |
||||||||
|
10 |
4 ->4 |
≤0.5–2 |
|
|
|
|
|
|
|
|
|
|
+ |
− |
|
|
Group IIa |
1 |
0.5 |
1 |
|
|
|
|
|
|
|
|
Lys |
Ser |
− |
− |
|
1 |
1 |
1 |
|
Asn |
Glu |
Lys |
Ser |
− |
− |
||||||
|
1 |
1 |
1 |
|
Asn |
|
|
|
|
|
|
Lys |
|
− |
− |
|
|
Group IIb |
1 |
1 |
1 |
|
|
|
|
|
|
Glu |
Val |
Lys |
|
− |
− |
|
2 |
0.5–1 |
1 |
|
Asn |
|
Ile |
|
|
|
Val |
Lys |
|
− |
− |
|
|
Group IIc |
2 |
1 |
1 |
|
|
|
|
|
|
|
Thr |
Lys |
|
− |
− |
|
2 |
1 |
1 |
|
Asn |
|
|
|
|
|
Thr |
Lys |
|
− |
− |
|
|
Group IId |
1 |
1 |
1 |
|
|
|
|
|
Val |
|
|
Lys |
|
− |
− |
|
Miscellaneous |
10 |
0.25–0.5 |
≤0.5–1 |
|
Asn |
|
− |
− |
|||||||
|
1 |
≤0.12 |
≤0.5 |
Val |
|
− |
− |
|||||||||
|
1 |
>4 |
2 |
|
Asn |
|
− |
+ |
||||||||
|
1 |
>4 |
≤0.5 |
|
Asn |
|
+ |
− |
||||||||
|
1 |
≤0.12 |
≤0.5 |
|
Asn |
Ser |
|
− |
− |
|||||||
|
1 |
0.25 |
≤0.5 |
|
|
Thr |
|
|
|
|
|
|
|
− |
− |
|
*β-lactamase production: positive (+), negative (−).
†The ratio of amoxicillin/clavulanic acid was 2 : 1.
AMC, amoxicillin/clavulanic acid; AMP, ampicillin; MIC, Minimum inhibitory concentration.