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Table 2 In vitro activities of nine antibiotics against isolated B. fragilis

From: Antibiotic resistance pattern of Bacteroides fragilis isolated from clinical and colorectal specimens

Antibioticss

Patient Group (clinical samples)

All

Healthy Group (colorectal samples)

Range

MIC (µg/mL)

R%

Range

MIC (µg/mL)

R%

Range

MIC (µg/mL)

R%

MIC50

MIC90

MIC50

MIC90

MIC50

MIC90

Penicillin G

4->256

256

>256

100

4->256

128

 > 256

100

4->256

128

 > 256

100

Ampicillin-sulbactam

1–128

4

16

9.1

0.125–256

1

8

5.45.4

0.125–256

1

16

6.4

Piperacillin-tazobactam

0.06–256

1

64

9.1

0.06–128

0.5

4

1.8

0.06–256

0.4

4

2.6

Cefoxitin

2–256

16

256

45.5

2–256

8

256

35.7

2–256

16

256

38.5

Imipenem

0.06–4

0.5

4

0

0.064–16

0.5

4

1.8

0.06–16

0.5

4

1.3

Meropenem

0.064–4

0.25

2

0

0.064–16

0.25

2

1.8

0.06–16

0.1250.125

2

1.3

Tetracycline

1–128

32

64

81.8

0.125–128

32

64

71.4

0.125–128

32

64

74.4

Clindamycin

0.125->256

8

>256

54.5

0.125->256

2

256

42.9

0.125->256

16

256

41

Metronidazole

0.06–4

0.52

2

0

0.06–1

0.25

0.5

0

0.06–4

0.25

2

0

  1. R %, Resistance percentages; MIC50 and MIC90, the minimum inhibitory concentration required to inhibit 50% and 90% of the bacteria population.
  2. tetQ, ermF, ermB, cfiA, cepA, cfxA, mefA, nim genes and the insertion sequence IS1186 were further searched to evaluate antibiotic resistance by the PCR. Absolute and relative frequencies of resistance and insertion sequences genes are presented in Table 3.