Table 2.

Susceptibilities of S. pneumoniae isolates according to the presence or absence of erm(B) andmef(A) erythromycin resistance genes

MLS resistance genotype (no. of isolates) and antibiotic MIC (μg/ml)a
Range 50% 90% Geometric mean
erm(B) and mef(A) negative (125)
 Penicillin0.008–4 0.03 1 0.06
 Cefotaxime 0.004–1 0.01 0.25 0.02
 Telithromycin 0.002–0.06 0.01 0.06 0.01
 Erythromycin 0.008–2 0.03 0.06 0.02
 Clindamycin 0.008–0.12 0.03 0.06 0.03
 Quinupristin-dalfopristin 0.06–4 1 2 0.9
 Levofloxacin 0.12–1 1 1 0.65
erm(B) positive and mef(A) negative (73)
 Penicillin 0.01–4 0.5 20.45
 Cefotaxime 0.008–1 0.25 1 0.15
 Telithromycin 0.004–1 0.03 0.12 0.03
 Erythromycin 0.5–>64 >64 >64 45.0
 Clindamycin 0.06–>64 64 >64 18.7
 Quinupristin-dalfopristin 0.25–8 1 2 0.90
 Levofloxacin 0.25–8 0.5 1 0.57
erm(B) negative and mef(A) positive (4)
 Penicillin 0.03–2 0.17
 Cefotaxime 0.008–0.25 0.06
 Telithromycin0.01–0.5 0.09
 Erythromycin 0.5–82.82
 Clindamycin 0.03–0.06 0.04
 Quinupristin-dalfopristin 1–2 1.68
 Levofloxacin 0.25–2 0.84
erm(B) and mef(A) positive (1)
 Penicillin 0.5
 Cefotaxime 0.12
 Telithromycin0.06
 Erythromycin 64
 Clindamycin >64
 Quinupristin-dalfopristin 2
 Levofloxacin 1
  • a 50% and 90%, MICs at which 50 and 90% of isolates are inhibited, respectively.