Table 1. Mean SCC of mammary quarters according to the species of microorganisms as the cause of IMI in dairy cows.
| Pathogen isolated | No. of quarters | % of total quarters | % of culture positive | SCC (×103 cells/ml) (Mean ± SEM) | Level of significance |
|---|---|---|---|---|---|
| Quarters analyzed bacteriologically | 360 | ||||
| Culture negative | 232 | 64.4 | 32.72 ± 6.56 | p < 0.001 | |
| Culture positive | 128 | 35.6 | 210.52 ± 27.75 | ||
| Single infections | |||||
| Major pathogens | |||||
| S. aureus | 26 | 7.2 | 20.3 | 218.31 ± 56.81 | p < 0.001 |
| E. coli | 8 | 2.2 | 6.2 | 200.75 ± 86.73 | |
| Enterobacter spp. | 8 | 2.2 | 6.2 | 338.00 ± 96.80 | |
| Minor pathogen | p < 0.001 | ||||
| Coagulase-negative Staphylococci (CNS) | 22 | 6.1 | 17.2 | 267.73 ± 121.42 | |
| Others | p < 0.001 | ||||
| Bacillus spp. | 10 | 2.8 | 7.8 | 319.20 ± 126.37 | |
| P. aeruginosa | 6 | 1.7 | 4.7 | 66.33 ± 19.81 | |
| Unidentified | 16 | 4.4 | 12.5 | 115.25 ± 17.05 | |
| Mixed infections | |||||
| S. aureus and E. coli | 6 | 1.7 | 4.7 | 118.00 ± 17.63 | p < 0.001 |
| S. aureus and Enterobacter spp. | 4 | 1.1 | 3.1 | 176.00 ± 72.17 | |
| S. aureus and P. aeruginosa | 2 | 0.6 | 1.6 | 202.00 ± 0.00 | |
| S. aureus and unidentified | 2 | 0.6 | 1.6 | 61.00 ± 0.00 | |
| E. coli and CNS | 2 | 0.6 | 1.6 | 273.000 ± 0.00 | |
| E. coli and Bacillus spp. | 2 | 0.6 | 1.6 | 138.00 ± 0.00 | p < 0.001 |
| E. coli and unidentified | 2 | 0.6 | 1.6 | 206.00 ± 0.00 | |
| Enterobacter spp. and Bacillus spp. | 2 | 0.6 | 1.6 | 84.00 ± 0.00 | |
| Enterobacter spp. and unidentified | 2 | 0.6 | 1.6 | 302.00 ± 0.00 | |
| Bacillus spp. and Pseudomonas spp. | 4 | 1.1 | 3.1 | 400.50 ± 45.89 | |
| Bacillus spp. and unidentified | 4 | 1.1 | 3.1 | 22.50 ± 2.59 | |