Table 3 Drug resistance patterns of Gram-negative bacterial isolates against commonly used antibiotics from the three Referral Hospitals of Amhara region, Ethiopia; 2017–2018

E. coli (n = 46)

S

2

8

6

11

25

31

24

12

11

29

22

16

I

–

4

1

4

2

2

3

10

4

5

5

6

R

44

34

39

31

19

13

19

24

31

12

19

24

Klebsiella spp. (n = 38)

S

–

7

8

8

23

17

11

2

9

11

6

6

I

–

1

–

5

4

5

1

6

3

6

7

6

R

38

30

30

25

11

16

26

30

26

21

25

26

Proteus Spp. (n = 13)

S

2

2

1

3

7

6

4

4

2

4

3

2

I

–

1

–

2

1

–

1

1

2

2

2

4

R

11

10

12

8

5

7

8

8

9

7

8

7

Enterobacter Spp. (n = 13)

S

–

1

2

7

8

5

5

1

2

5

3

2

I

–

1

–

–

–

–

–

2

1

2

–

1

R

13

11

11

6

5

8

8

10

10

6

10

10

Citrobacter Spp. (n = 12)

S

–

1

3

2

6

3

6

3

2

3

1

4

I

–

1

1

1

1

–

–

1

1

–

1

2

R

12

10

8

9

5

9

6

8

9

9

10

6

P. aeruginosa (n = 6)

S

–

–

–

3

3

–

4

–

–

3

–

–

I

–

2

–

–

1

1

–

1

1

2

–

1

R

6

4

6

3

2

5

2

5

5

1

6

5

Providencia Spp. (n = 6)

S

–

–

–

–

1

4

5

1

–

1

–

–

I

–

–

–

–

–

–

–

–

1

–

1

1

R

6

6

6

6

5

2

1

5

5

5

5

5

Salmonella Spp. (n = 3)

S

–

–

1

–

1

2

1

1

1

1

1

1

I

–

–

–

1

–

–

–

–

–

–

–

–

R

3

3

2

2

2

1

2

2

2

2

2

2

Others (n = 4)^a

S

–

3

3

2

3

4

3

3

2

2

3

3

I

–

–

–

1

–

–

–

–

–

–

–

1

R

4

1

1

1

–

1

1

2

2

1

–

Total(n = 141)

S

4 (2.8)

22 (15.6)

24 (17.0)

36 (25.5)

77 (54.6)

72 (51.0)

63 (44.7)

27 (19.1)

29 (20.6)

59 (41.8)

39 (27.7)

34 (24.1)

I

–

10 (7.1)

2 (1.4)

14 (9.9)

9 (6.4)

8 (5.7)

5 (3.5)

21 (14.9)

13 (9.2)

17 (12.1)

16 (11.3)

22 (15.6)

R

137 (97.2)

109 (77.3)

115 (81.6)

91 (64.5)

55 (39.0)

61 (43.3)

73 (51.8)

93 (66.0)

99 (70.2)

65 (46.1)

86 (61.0)

85 (60.3)