TABLE 3.
Macrolides, lincosamides and streptogramins (MLS): susceptibility, resistance phenotypes and genotypes of invasive non-beta-hemolytic Streptococcus isolates
| Streptococcus group | Resistant isolates, n (%) |
Disk diffusion phenotypea, n (%) |
ClindaRb
n (%) |
Resistance determinants, n (%)c |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| L/lSAg | M | iMLSB | cMLSB | DDd | BMDe | mef | erm(A) | erm(B) | lnu(C) | lsa(A) | Othersf | ||
| anginosus (n = 172) | 53 (30.8%) | 9 (17.0%) | 2 (3.8%) | 0 (0%) | 42 (79.2%) | 51 (29.7%) | 33 (21.3%) | 3 (5.7%) | 6 (11.3%) | 35 (66.0%) | 0 (0%) | 9 (17.0%) | 6 (11.3%) |
| bovis/equinus (n = 77) | 53 (68.8%) | 22 (41.5%) | 0 (0%) | 1 (1.9%) | 30 (56.6%) | 53 (68.8%) | 20 (26.0%) | 0 (0%) | 3 (5.7%) | 23 (43.4%) | 11 (13.4%) | 2 (3.8%) | 5 (9.4%) |
| mitis (n = 148) | 53 (35.8%) | 2 (3.8%) | 33 (62.3%) | 2 (3.8%) | 16 (30.2%) | 20 (37.8%) | 18 (34.0%) | 38 (71.7%) | 6 (11.3%) | 11 (20.8%) | 0 (0%) | 0 (0%) | 1 (1.9%) |
| mutans (n = 5) | 0 | NA | NA | NA | NA | 0 | 0 | NA | NA | NA | NA | NA | NA |
| salivarius (n = 39) | 17 (43.6%) | 0 (0%) | 12 (70.6%) | 0 (0%) | 5 (29.4%) | 5 (12.8%) | 4 (10.3%) | 13 (76.5%) | 0 (0%) | 5 (29.4%) | 0 (0%) | 0 (0%) | 0 (0%) |
| sanguinis (n = 81) | 46 (56.8%) | 1 (2.2%) | 26 (56.5%) | 0 (0%) | 19 (41.3%) | 20 (24.7%) | 19 (23.5%) | 28 (60.9%) | 4 (8.7%) | 15 (32.6%) | 0 (0%) | 1 (2.2%) | 1 (2.2%) |
| Totale (n = 522) | 222 (42.5%) | 34 (15.3%) | 73 (32.9%) | 3 (1.4%) | 112 (50.7%) | 149 (28.5%) | 94 (18.6%) | 82 (36.9%) | 19 (8.6%) | 89 (40.1%) | 11 (5.0%) | 12 (5.4%) | 13 (5.9%) |
DD phenotypes were interpreted according to the guidelines on Antibiotic Susceptibility Testing of the French Society for Microbiology (CA-SFM).
Minimum inhibitory concentrations of clindamycin were measured by BMD and interpreted according to EUCAST clinical breakpoint table v 13.0.
Percentages are relative to total resistant isolates within each group.
Including the L/LSA, iMLSB and cMLSB phenotypes.
A total of 17 S. intermedius isolates could not be tested by BMD but only by DD because of insufficient growth in MH-F broth. These included 5 MLS resistant isolates of which 4 cMLSB phenotypes and 1 L phenotype.
Including erm (T) (5 in the bovis/equinus group), lnu (A) (2 in the anginosus group), lnu (D) (1 in the mitis group), lnu (E) (1 in the anginosus group), and lsa (B) (3 in the anginosus group and 1 in the sanguinis group).
BMD, broth microdilution; ClindaR, clindamycin resistance; DD, disk diffusion; L, resistance to lincosamides; LSA, resistance to lincosamides and streptogramin A; M, efflux-mediated resistance to C14 and C15 macrolides; iMLSB, inducible resistance to macrolides, lincosamides, and streptogramin B; cMLSB, constitutive resistance to macrolides, lincosamides, and streptogramin B; NA, not applicable.