TABLE 3.

Score-based evaluation of gross lesions in organs of infected chickens

E. coli strainMean lesion score ± SEMa
Air sacsbLiver and heartc
χ71222.7 ± 0.23.2 ± 0.3
χ7304 (Δiro ΔiucABC iutA)1.5 ± 0.4*0.8 ± 0.3**
χ7304(pYA3661 iroBCDEN)2.8 ± 0.33.2 ± 0.2
χ7304(pIJ34 iroBCDE)1.6 ± 0.4*1.3 ± 0.5*
χ7304(pIJ37 iroBDEN)1.4 ± 0.3**1.0 ± 0.2**
χ7304(pIJ135 iroBCN)1.4 ± 0.3**0.8 ± 0.1**
χ7304(pIJ136 iroBCEN)1.9 ± 0.31.4 ± 0.1**
χ7304(pIJ137 iroBCDN)2.7 ± 0.32.4 ± 0.4
  • a Lesion scores are presented as the mean (± standard error of the mean [SEM]) of values attributed to gross lesions of airsacculitis and combined lesions of perihepatitis/and perihepatitis as described in reference 33.

  • b Mean lesion scores for airsacculitis in both caudal thoracic air sacs.

  • c Combined lesion scoring values for pericarditis and perihepatitis. Statistical differences compared with the wild-type strain using the two-tailed Mann-Whitney test are noted: * and **, P < 0.05 and P < 0.001, respectively.