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Table 1 In vitro susceptibility testing of key antibiotics against different sequence types of 501 methicillin–resistant Staphylococcus aureus blood isolates

From: Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in Taiwan

 

Total (n = 501)

ST8 (n = 157)

ST239 (n = 64)

ST59 (n = 108)

CC45a (n = 63)

other STs (n = 109)

Moxifloxacin

 Rangeb (µg/mL)

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 MIC50/MIC90(µg/mL)

2/ > 4

2/ > 4

 > 4/ > 4

 ≤ 0.25/2

2/4

 ≤ 0.25/4

 Sc, n (%)

188 (37.5)

2 (1.3)

1 (1.6)

93 (86.1)

21 (33.3)

71 (65.1)

Levofloxacin

 Rangeb (µg/mL)

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 MIC50/MIC90(µg/mL)

 > 4/ > 4

 > 4/ > 4

 > 4/ > 4

0.25/ > 4

 > 4/ > 4

0.5/ > 4

 Sc, n (%)

188 (37.5)

2 (1.3)

1 (1.6)

93 (86.1)

21 (33.3)

71 (65.1)

Ciprofloxacin

 Rangeb (µg/mL)

1– > 2

1– > 2

1– > 2

1– > 2

1– > 2

1– > 2

 MIC50/MIC90(µg/mL)

 > 2/ > 2

 > 2/ > 2

 > 2/ > 2

1/ > 2

 > 2/ > 2

1/ > 2

 Sc, n (%)

177 (35.3)

2 (1.3)

1 (1.6)

87 (80.6)

21 (33.3)

66 (60.6)

Vancomycin

 Rangeb (µg/mL)

0.5–4

0.5–2

1–2

0.5–4

0.5–2

0.5–2

 MIC50/MIC90(µg/mL)

1/1

1/1

1/2

1/1

1/1

1/1

 Sc, n (%)

500 (99.8)

157 (100.0)

64 (100.0)

107 (99.1)

63 (100.0)

109(100.0)

Daptomycin

 Rangeb (µg/mL)

 ≤ 0.5–2

 ≤ 0.5–1

 ≤ 0.5–2

 ≤ 0.5–2

 ≤ 0.5–1

 ≤ 0.5–1

 MIC50/MIC90(µg/mL)

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/1

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/ ≤ 0.5

 Sc, n (%)

499 (99.6)

157 (100.0)

63 (98.4)

107 (99.1)

63 (100.0)

109(100.0)

Linezolid

 Rangeb (µg/mL)

 ≤ 1–4

 ≤ 1–4

 ≤ 1–2

 ≤ 1–2

 ≤ 1–4

 ≤ 1–4

 MIC50/MIC90(µg/mL)

2/2

2/2

2/2

2/2

2/2

2/2

 Sc, n (%)

501 (100.0)

157 (100.0)

64 (100.0)

108 (100.0)

63 (100.0)

109(100.0)

Gentamicin

 Rangeb (µg/mL)

 ≤ 2– > 16

 ≤ 2– > 16

16– > 16

 ≤ 2– > 16

 ≤ 2– > 16

 ≤ 2– > 16

 MIC50/MIC90(µg/mL)

8/ > 16

 ≤ 2/16

 > 16/ > 16

16/ > 16

4/16

8/ > 16

 Sc, n (%)

246 (49.1)

128 (81.5)

0 (0)

38 (35.2)

32 (50.8)

48 (44.0)

Rifampin

 Rangeb (µg/mL)

 ≤ 0.5– > 4

 ≤ 0.5– > 4

 ≤ 0.5– > 4

 ≤ 0.5–1

 ≤ 0.5– > 4

 ≤ 0.5– > 4

 MIC50/MIC90(µg/mL)

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/2

 Sc, n (%)

475 (94.8)

156 (99.4)

61 (95.3)

108 (100.0)

61 (96.8)

89 (85.6)

TMP/SMX

 Rangeb (µg/mL)

 ≤ 0.5– > 4

 ≤ 0.5– > 4

 ≤ 0.5– > 4

 ≤ 0.5– > 4

 ≤ 0.5–2

 ≤ 0.5– > 4

 MIC50/MIC90(µg/mL)

 ≤ 0.5/ > 4

 ≤ 0.5/ ≤ 0.5

 > 4/ > 4

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/ ≤ 0.5

 ≤ 0.5/1.2

 Sc, n (%)

426 (85.0)

154 (98.1)

3 (4.7)

106 (98.1)

63 (100.0)

100 (91.7)

Tetracycline

 Rangeb (µg/mL)

 ≤ 2– > 16

 ≤ 2– > 16

 ≤ 2– > 16

 ≤ 2– > 16

 ≤ 2– > 16

 ≤ 2– > 16

 MIC50/MIC90(µg/mL)

2/ > 16

2/16

 > 16 > 16

2/16

 > 16/ > 16

2/ > 16

 Sc, n (%)

317 (63.3)

140 (89.2)

2 (3.1)

79 (73.1)

26 (41.3)

70 (64.2)

Clindamycin

 Rangeb (µg/mL)

 ≤ 0.5– > 2

 ≤ 0.5– > 2

 ≤ 0.5– > 2

 ≤ 0.5– > 2

 ≤ 0.5– > 2

 ≤ 0.5– > 2

 MIC50/MIC90(µg/mL)

 ≤ 0.5/ > 2

 ≤ 0.5/ ≤ 0.5

 > 2/ > 2

 > 2/ > 2

 ≤ 0.5/ > 2

 ≤ 0.5/ > 2

 Sc,d, n (%)

277 (55.3)

144 (91.7)

2 (3.1)

15 (13.9)

54 (85.7)

62 (56.9)

Erythromycin

 Rangeb (µg/mL)

 ≤ 0.25– > 4

 ≤ 0.25– > 4

0.5– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 ≤ 0.25– > 4

 MIC50/MIC90(µg/mL)

 > 4/ > 4

 > 4/ > 4

 > 4/ > 4

 > 4/ > 4

 > 4/ > 4

 > 4/ > 4

 Sc,d, n (%)

98 (19.6)

20 (12.7)

1 (1.6)

10 (9.3)

27 (42.9)

40 (36.7)

  1. ST sequence type, CC clonal complex, MIC50/MIC90 the lowest concentration of the antibiotics at which 50% and 90% of the isolates were inhibited, respectively, S susceptible, TMP/SMX trimethoprim/sulfamethoxazole
  2. aAmong CC45, ST45 and ST508 were clustered within a band pattern similarity of ≥ 80% by PFGE
  3. bDilution range of each antibiotic tested are listed as follows: 0.25–4 µg/mL for moxifloxacin and levofloxacin, 1–2 µg/mL for ciprofloxacin, 0.25–32 µg/mL for vancomycin, 0.5–4 µg/mL for daptomycin, rifampin and erythromycin, 1–8 µg/mL for linezolid, 2–16 µg/mL for gentamicin and tetracycline, 0.5/9.5–4/76 for TMP/SMX, and 0.5–2 µg/mL for clindamycin
  4. cThe CLSI clinical breakpoints for each antibiotic are as follows: S ≤ 0.5 µg/mL for moxifloxacin, S ≤ 1 µg/mL for levofloxacin, S ≤ 1 µg/mL for ciprofloxacin, S ≤ 2 µg/mL for vancomycin, S ≤ 1 µg/mL for daptomycin, S ≤ 4 µg/mL for linezolid, S ≤ 4 µg/mL for gentamicin, S ≤ 1 µg/mL for rifampin, S ≤ 2/38 for TMP/SMX, S ≤ 4 µg/mL for tetracycline, S ≤ 0.5 µg/mL for clindamycin, and S ≤ 0.5 µg/mL for erythromycin
  5. dFor isolates that tested erythromycin resistant and clindamycin susceptible or intermediate, testing for inducible clindamycin resistance by broth microdilution was performed to determine susceptibility to clindamycin
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Annals of Clinical Microbiology and Antimicrobials

ISSN: 1476-0711

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