Table 3

Distribution of antimicrobial resistance among four main sequence types of 82 Escherichia coli causing bovine mastitis

Resistance*Prevalence by sequence type (n, %)
ST10ST58ST88ST1125Other
(n=7)(n=8)(n=6)(n=9)(n=52)
AM4 (50.0)3 (50.0)1 (11.1)10 (19.2)
AMC1 (12.5)1 (16.7)
EFT1 (14.3)
CN2 (25.0)1 (16.7)
TE4 (50.0)1 (16.7)7 (13.5)
SXT3 (37.5)1 (16.7)4 (7.7)
MDR3 (37.5)1 (16.7)4 (7.7)
  • *Antimicrobial susceptibility was determined using the disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines and breakpoints.36

  • –, no resistance detected; AM, ampicillin; AMC, amoxicillin/clavulanic acid; CN, gentamicin; EFT, ceftiofur; MDR, multidrug resistant (resistant to three or more classes of antimicrobials); SXT, sulfamethoxazole/trimethoprim; TE, tetracycline.