Skip to main content
. 2017 Dec 4;4:207. doi: 10.3389/fvets.2017.00207

Table 3.

Distribution of minimum inhibitory concentrations among Mannheimia haemolytica isolates (n = 219 animals, 233 samples: lung samples = 208, nasal swabs = 16, pleural fluid = 7, heart = 1, joint fluid = 1).

Distribution (%) of MICs (μg/mL)
Class Categorya Antimicrobial MIC 50 %Rb ≤0.12 0.25 0.5 1 2 4 8 16 32 64
Aminoglycoside II GEN 4 3.4c 4.3 38.6 50.6 3.0 3.4
II NEO 8 49.4c 13.7 36.9 1.3 48.1
III SPE 32 4.3 1.7 20.2 73.0 64 = 0.9
>64 = 4.3
Fluorquinolone I ENRO 0.12 3.0 94 1.3 1.3 0.4 3.0
I DANO 0.12 3.9c 91 4.3 0.9 3.9
Macrolide II TYLT 32 99.1c 0.4 0.4 4.3 94.8
II TUL 16 37.8 4.3 6.9 14.6 17.6 14.2 4.7 37.8
II TIL 16 44.2 34.8 8.6 12.4 5.6 38.6
B lactams I XNL 0.25 0.9 96.6 0.4 1.7 0.4 0.9
II PEN 0.12 7.2 51.9 36.5 4.3 1.7 0.4 0.4 4.7
II AMP 0.25 5.1c 92.3 1.3 1.3 0.9 0.4 0.4 3.4
Lincosamides II CLIN 8 77.7c 0.9 0.9 2.1 18.5 57.5 20.2
Phenicol III FFN 1 4.3 1.7 39.9 51.1 2.1 0.9 4.3
Tetracycline III OXY 8 53.6 20.6 20.6 4.3 0.9 53.6
III CTET 2 11.2 8.2 30.0 25.8 24.9 11.2
Pleuromutilin III TIA 16 19.7c 0.4 1.7 3.9 9.4 64.8 19.7

Trimethoprim sulphac (Category II): <2/38 = 98.3%, >2/38 = 1.7%.

Sulphahdimethoxinec (Category III): <256 = 44.6%, >256 = 55.4%.

GEN, gentamycin/NEO, neomycin/SPE, spectinomycin; DAN, danofloxacin/ENRO, enrofloxacin; TYLT, tylosin/TUL, tulathromycin/TIL, tilmicosin; PEN, penicillin/AMP, ampicillin/XNL, ceftiofur; CLI, clindamycin; FFN, florfenicol; SXT, trimethoprim sulpha/SDM, sulphadimethoxine; OXY, oxytetracycline; CTET, chlortetracycline; TIA, tiamulin.

aCategorization of antimicrobial drugs based on importance in human medicine—Veterinary Drug Directorate.

bPathogen minimum inhibitory concentration breakpoints from CLSI standards.

cNo CLSI breakpoint for this bovine respiratory disease pathogen/antimicrobial combination, simply notes susceptibility.

Values in red indicate resistant proportion of samples.

Shaded areas indicate concentrations not tested.