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Table 1 Resistance and distribution of MIC for Staphylococcus aureus (n = 109) and coagulase negative staphylococci (CNS; n = 95).

From: Etiology and antimicrobial susceptibility of udder pathogens from cases of subclinical mastitis in dairy cows in Sweden

   

Distribution (%) of MICsa(mg/l)

Substance

Species

Resistance

(%)

≤0.03

0.06

0.12

0.25

0.5

1

2

4

8

16

32

64

>64

Cephalothin

S. aureus

0

 

0.9

46.7

45.0

6.4

        
 

CNS

-

 

4.2

25.3

53.7

9.5

6.3

4.2

      

Chloramphenicol

S. aureus

0

      

0.9

21.1

75.0

3.0

   
 

CNS

0

     

1.1

6.3

71.6

21.2

    

Ciprofloxacin

S. aureus

0

 

1.8

17.4

55.0

24.8

0.9

       
 

CNS

0

 

7.4

48.4

37.9

6.3

        

Clindamycin

S. aureus

-

   

91.7

8.3

        
 

CNS

-

   

80.9

15.8

2.1

     

1.1

 

Erythromycin

S. aureus

0

   

12.8

79.8

7.3

       
 

CNS

2

   

30.5

60.0

7.4

0

  

1.1

 

1.1

 

Gentamicin

S. aureus

0

    

67.0

31.2

1.8

      
 

CNS

1

    

98.9

1.1

       

Kanamycin

S. aureus

4

   

0.9

0.9

12.8

60.6

21.1

 

2.8

0.9

  
 

CNS

-

   

11.6

42.1

38.9

5.3

2.1

     

Oxacillin

S. aureus

0

   

41.2

47.7

10.1

0.9

      
 

CNS

10

  

0.9

40.0

43.2

5.3

8.4

2.1

     

Penicillinc

S. aureus

4

35.8

43.1

17.4

  

0.9

1.8

 

0.9

    
 

CNS

37

36.8

13.7

13.7

10.5

13.7

8.4

1.1

1.2

1.1

    

Tetracycline

S. aureus

3

    

95.4

1.8

2.8

      
 

CNS

1

    

87.4

11.6

     

1.1

 

Trimethoprim

S. aureus

-

    

3.7

12.8

61.5

18.3

3.7

    
 

CNS

-

    

9.5

25.3

31.6

10.5

12.6

8.4

1.1

1.1

 
  1. a Thin vertical lines denote range of dilutions tested for each substance. MICs above the range are given as the concentration closest to the range. MICs equal to or lower than the lowest concentration tested are given as the lowest tested concentration. Bold vertical lines indicate EUCAST epidemiological cut-off values with exception of clindamycin and trimethoprim since the given cut-off value would have split- the distribution in an inappropriate way. When no cut-off value is available isolates are not classified as susceptible or resistant.
  2. b The isolates with MIC above cut-off were tested for the presence of mecA gene by PCR. None were positive.
  3. c NA = not applicable since classification susceptible or resistant was done according to beta-lactamase production.
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Acta Veterinaria Scandinavica

ISSN: 1751-0147