TABLE 2.
Beta-lactam agents: susceptibility and MIC distributions of invasive non-beta-hemolytic Streptococcus isolates
| Streptococcus group (n; %) | Antimicrobial agent | MICa (mg/L), n |
MIC interpretationb, n (%) |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.008 | 0.016 | 0.032 | 0.064 | 0.125 | 0.25 | 0.5 | 1 | 2 | ≥4 | S | I | R | ||
|
anginosus (172; 33.0%) |
Benzylpenicillin | 13 | 23 | 18 | 92 | 26 | 0 | 0 | 0 | 0 | 0 | 172 (100%) | 0 | 0 |
| Ampicillinc | 4 | 3 | 17 | 31 | 51 | 47 | 2 | 0 | 0 | 0 | 155 (100%) | 0 | 0 | |
| Amoxicillin | 4 | 6 | 19 | 40 | 56 | 45 | 2 | 0 | 0 | 0 | 172 (100%) | 0 | 0 | |
| Cefotaxime | 0 | 4 | 10 | 13 | 41 | 95 | 9 | 0 | 0 | 0 | 172 (100%) | NAd | 0 | |
| Ceftriaxone | 0 | 2 | 6 | 11 | 27 | 54 | 72 | 0 | 0 | 0 | 172 (100%) | NA | 0 | |
| bovis/equinus (77; 14.8%) | Benzylpenicillin | 0 | 0 | 2 | 55 | 19 | 1 | 0 | 0 | 0 | 0 | 77 (100%) | 0 | 0 |
| Ampicillin | 0 | 0 | 0 | 14 | 62 | 1 | 0 | 0 | 0 | 0 | 77 (100%) | 0 | 0 | |
| Amoxicillin | 0 | 0 | 0 | 17 | 59 | 1 | 0 | 0 | 0 | 0 | 77 (100%) | 0 | 0 | |
| Cefotaxime | 0 | 0 | 1 | 20 | 52 | 4 | 0 | 0 | 0 | 0 | 77 (100%) | NA | 0 | |
| Ceftriaxone | 0 | 0 | 1 | 18 | 10 | 46 | 2 | 0 | 0 | 0 | 77 (100%) | NA | 0 | |
|
mitis (148; 28.4%) |
Benzylpenicillin | 12 | 17 | 28 | 14 | 15 | 20 | 11 | 9 | 5 | 17 | 106 (71.6%) | 25 (16.9%) | 17 (11.5%) |
| Ampicillin | 0 | 8 | 15 | 46 | 8 | 20 | 11 | 11 | 8 | 21 | 108 (73.0%) | 19 (12.8%) | 21 (14.2%) | |
| Amoxicillin | 1 | 10 | 25 | 37 | 17 | 16 | 4 | 11 | 8 | 19 | 110 (74.3%) | 19 (12.8%) | 19 (12.8%) | |
| Cefotaxime | 2 | 10 | 11 | 30 | 29 | 21 | 18 | 3 | 9 | 15 | 121 (81.8%) | NA | 27 (18.2%) | |
| Ceftriaxone | 0 | 5 | 13 | 14 | 41 | 17 | 23 | 10 | 7 | 18 | 113 (76.4%) | NA | 35 (23.6%) | |
|
mutans (5; 1.0%) |
Benzylpenicillin | 0 | 2 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 5 (100%) | 0 | 0 |
| Ampicillin | 0 | 0 | 0 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 5 (100%) | 0 | 0 | |
| Amoxicillin | 0 | 0 | 0 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 5 (100%) | 0 | 0 | |
| Cefotaxime | 0 | 0 | 2 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 5 (100%) | NA | 0 | |
| Ceftriaxone | 0 | 0 | 0 | 2 | 3 | 0 | 0 | 0 | 0 | 0 | 5 (100%) | NA | 0 | |
|
salivarius (39; 7.5%) |
Benzylpenicillin | 0 | 0 | 1 | 8 | 10 | 10 | 2 | 6 | 1 | 1 | 29 (74.4%) | 9 (23.1%) | 1 (2.6%) |
| Ampicillin | 0 | 1 | 0 | 5 | 10 | 9 | 6 | 5 | 2 | 1 | 31 (79.5%) | 7 (18.0%) | 1 (2.6%) | |
| Amoxicillin | 0 | 1 | 2 | 6 | 8 | 9 | 8 | 2 | 2 | 1 | 34 (87.2%) | 4 (10.3%) | 1 (2.6%) | |
| Cefotaxime | 1 | 0 | 6 | 8 | 9 | 8 | 6 | 1 | 0 | 0 | 38 (97.4%) | NA | 1 (2.6%) | |
| Ceftriaxone | 0 | 0 | 1 | 9 | 9 | 6 | 9 | 4 | 1 | 0 | 34 (87.2%) | NA | 5 (12.8%) | |
|
sanguinis (81; 15.5%) |
Benzylpenicillin | 4 | 8 | 0 | 1 | 21 | 15 | 14 | 10 | 6 | 2 | 49 (60.5%) | 30 (37.0%) | 2 (2.5%) |
| Ampicillin | 0 | 0 | 3 | 9 | 1 | 7 | 21 | 16 | 13 | 11 | 41 (50.6%) | 29 (35.8%) | 11 (13.6%) | |
| Amoxicillin | 0 | 0 | 0 | 10 | 3 | 9 | 20 | 20 | 14 | 5 | 42 (51.9%) | 34 (42.0%) | 5 (6.2%) | |
| Cefotaxime | 0 | 1 | 11 | 20 | 13 | 16 | 9 | 9 | 1 | 1 | 70 (86.4%) | NA | 11 (13.6%) | |
| Ceftriaxone | 0 | 0 | 6 | 10 | 26 | 10 | 13 | 8 | 7 | 1 | 65 (80.2%) | NA | 16 (19.8%) | |
a
MICs determined by broth microdilution except in the case of 17 S. intermedius isolates (anginosus group) for which MICs could only be measured by gradient Etest because of insufficient growth in MH-F broth.
b
MICs interpretation according to EUCAST v 13.0. Susceptible isolates in shaded area, resistant isolates underlined.
c
Ampicilllin MICs were not determined for 17 S. intermedius isolates (anginosus group), neither by broth microdilution because of insufficient growth in MH-F broth nor by gradient Etest.
d
NA, not applicable; S, susceptible; I, susceptible increased exposure; R, resistant.