Table 2.
Comparison of antimicrobial resistance rates of invasive H. influenzae during the two study periods
|
Antimicrobial compound |
MIC breakpoints (CLSI) |
First period* |
Second period |
P-value |
|||||
|---|---|---|---|---|---|---|---|---|---|
|
2008–2013 (n=70) |
2014–2019 (n=68) |
||||||||
|
S ≤ |
R ≥ |
MIC50 (mg l−1) |
MIC90 (mg l−1) |
%R |
MIC50 (mg l−1) |
MIC90 (mg l−1) |
%R |
||
|
Ampicillin |
1 |
4 |
0.25 |
2 |
10 |
0.25 |
>4 |
17.6 |
0.22 |
|
Amoxicillin/clavulanic acid† |
4 |
8 |
≤0.5 |
2 |
0 |
≤0.5 |
1 |
0 |
1 |
|
Cefuroxime |
4 |
16 |
1 |
2 |
0 |
≤0.5 |
1 |
1.5 |
0.49 |
|
Cefepime |
2 |
4 |
≤0.25 |
≤0.25 |
0 |
≤0.25 |
≤0.25 |
1.5 |
0.49 |
|
Cefotaxime |
2 |
4 |
≤0.06 |
≤0.06 |
0 |
≤0.06 |
≤0.06 |
0 |
1 |
|
Ceftriaxone |
2 |
4 |
≤0.12 |
≤0.12 |
0 |
≤0.12 |
≤0.12 |
0 |
1 |
|
Imipenem |
4 |
8 |
0.5 |
1 |
0 |
≤0.12 |
0.25 |
0 |
1 |
|
Chloramphenicol |
2 |
8 |
≤1 |
≤1 |
0 |
≤1 |
≤1 |
0 |
1 |
|
Tetracycline |
2 |
8 |
≤1 |
2 |
0 |
≤1 |
≤1 |
0 |
1 |
|
Ciprofloxacin |
1 |
2 |
≤0.03 |
≤0.03 |
0 |
≤0.03 |
≤0.03 |
4.4 |
0.12 |
|
Co-trimoxazole‡ |
0.5 |
4 |
≤0.5 |
>2 |
26 |
≤0.5 |
>2 |
27.9 |
0.85 |
|
Azithromycin |
4 |
8 |
1 |
2 |
1.4 |
2 |
4 |
0 |
0.49 |
*Only 70 of the 82 strains of the first period were viable.
†The ratio of amoxicillin/clavulanic acid was 2 : 1.
‡The ratio of co-trimoxazole was 1 : 19.
MIC, Minimum inhibitory concentration; R, resistant; %R, resistance rate; S, susceptible.