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Table 8 Likelihood of identifying resistance among NTSEC isolates recovered from individuals that were culture-positive for M haemolytica to those that were culture-negative, stratified by sample time1,2

From: Methodological comparisons for antimicrobial resistance surveillance in feedlot cattle

Resistance outcome in fecal E. coli3

Sample Time

M. haemolyticaCulture Status4

OR5

95% CI6

P-value

Ampicillin

First

Positive

1.2

0.3 – 4.8

0.78

  

Negative

ref

  
 

Second

Positive

3.3

0.4 – 26.8

0.19

  

Negative

ref

  

Streptomycin

First

Positive

0.4

0.2 – 0.9

0.04

  

Negative

ref

  
 

Second

Positive

0.5

0.1 – 2.3

0.46

  

Negative

ref

  

Sulfisoxazole

First

Positive

0.8

0.4 – 1.7

0.56

  

Negative

ref

  
 

Second

Positive

1.5

0.5 – 4.4

0.50

  

Negative

ref

  

Teteracyline

First

Positive

1.1

0.5 – 2.5

0.82

  

Negative

ref

  
 

Second

Positive

0.9

0.4 – 2.2

0.90

  

Negative

ref

  
  1. 1n=377 isolates recovered from 186 individuals that were culture-positive for MH, and n=225 isolates recovered from 77 individuals that were culture-negative for MH.
  2. 2Susceptibility testing was performed using broth microdilution.
  3. 3Other drugs could not be analyzed because of low resistance prevalence (amikacin, amoxicillin-clavulanate, cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, ciprofloxacin, gentamicin, kanamycin, nalidixic acid, trimethoprim-sulfamethoxazole).
  4. 4Culture status regarding recovery of M. haemolytica from nasopharyngeal swabs.
  5. 5Analyses controlled for repeated measures and hierarchical data structure using generalized estimating equations (GEE), and fixed effects for feedlot, sample time, M. haemolytica culture-status, and a single interaction term for sample time*M. haemolytica culture-status.
  6. 695% confidence intervals.