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Table 1 Distribution of minimal inhibitory concentrations of antimicrobial agents tested in Streptococcus suis strains isolated from patients with meningitis

From: The antimicrobial resistance patterns and associated determinants in Streptococcus suisisolated from humans in southern Vietnam, 1997-2008

Antimicrobial Agent

Minimal Inhibitory Concentrations

 

Breakpoint* (mg/L)

Range (mg/L)

MIC50 # (mg/L)

MIC90 # (mg/L)

Resistant strains (%)

Tetracycline

S ≤ 2; R ≥ 8

0.125-->256

24

32

88.6

Erythromycin

S ≤ 0.25; R ≥ 1

0.016-- >256

0.064

>256

22.2

Chloramphenicol

S ≤ 4; R ≥ 16

0.5-96

3

4

8.6@

Penicillin

S ≤ 0.12; R ≥ 4

0.012-0.064

0.032

0.047

0

Ceftriaxone

S ≤ 0.5

0.025-0.38

0.094

0.125

0

Vancomycin

S ≤ 1

0.25-0.5

0.38

0.5

0

  1. *: Breakpoints are based on equivalent CLSI breakpoints for Streptococcus spp. viridans group
  2. #: MIC50, MIC90 are the MIC values inhibiting growth of 50% and 90% of tested isolates, respectively.
  3. @: Including the intermediate resistant isolates