TABLE 1.

Antibiotic susceptibility patterns for the six clusters derived by Ward's minimum variance method describing the patterns of resistance for the 209 E. coli isolates

ClusterTreatment group(s)bMIC50 with indicated antibioticaTotal no. of isolates
AMIAMPAUGAXOCHLCIPCOTFLOFOXGENKANNALSOXSTRTETTIO
A1, 226440.2580.0150.12440.5821632640.2521
B1, 22440.2580.0150.12440.5845123240.2566
C1, 22240.2580.0150.12440.58251232640.2525
D1, 22240.2580.0150.12420.582163240.2583
E2264644640.0150.253264321282512128641611
F2264640.580.0150.128160.5845121286413
  • a Boldface type represent MIC50s for the cluster that are classified as resistant according to the CLSI guidelines for E. coli, except for florfenicol, for which a value of >16 μg/ml was used. AMI, amikacin; AMP, ampicillin; AUG, amoxicillin-clavulanic acid; AXO, ceftriaxone; CHL, chloramphenicol; CIP, ciprofloxacin; COT, trimethoprim-sulfamethoxazole; FLO, florfenicol; FOX, cefoxitin; GEN, gentamicin; KAN, kanamycin; NAL, nalidixic acid; STR, streptomycin; SOX, sulfisoxazole; TET, tetracycline; TIO, ceftiofur.

  • b The treatment group that is represented in each cluster. 1, the nontreated group; 2, the treated group.