Table 1.

Macrolide resistance genes in Enterococcus sp. isolates with different macrolide resistance phenotypes.

Enterococcal speciesNo. of strainsMIC range (μg/ml)aPCR amplification
ERYAZMSPYPRI-ImsrAermAermBermCmefA/E
E. faecium12>128>12864–>12864–>128++
1>128>128>128 >128++
13264 0.5 1+b
9≤0.125–16≤0.125–640.5–41–2+
E. faecalis14>128>128>128 64–>128+
13≤0.125–8≤0.125–320.25–21–4
E. durans2>128>128>128 ≥128+
6≤0.125–0.25≤0.1250.25–2≤0.125–1
E. avium2>128>128>128 ≥128+
40.25–162–641–40.5–2
E. hirae8>128>128>128 4–16+
1≤0.50.5 4 1
E. gallinarum1>128>128>128 >128+
2≤0.5–12 4 1
E. casseliflavus2432 1 2–4
  • a ERY, erythromycin; AZM, azithromycin; SPY, spiramycin; PRI-I, pristinamycin I.

  • b A PCR product of 450 bp (larger than expected) was obtained.