TABLE 1.
Bacteriologically negative and positive quarter milk samples indicating pathogen-specific bacteria and groups isolated from samples with and without somatic cell counts above 200 000 cells/mL milk.
| Bacteria isolated | Total numbers of samples from which bacteria were isolated | Bacterial species as a % of the total samples | Bacterial species as a % of bacteria isolated | Number of quarters with an SCC > 200 000 cells/mL per bacterial species | As a % of all quarters with an SCC > 200 000 cells/mL per bacterial species† | As a % of bacteriological diagnoses with SCC > 200 000 cells/mL |
|---|---|---|---|---|---|---|
| Staphylococcus aureus (STA) | 3657 | 4.1 | 12.0 | 3125 | 7.2 | 85.5 |
| Staphylococcus aureus (STH) | 2430 | 2.7 | 8.0 | 2286 | 5.2 | 94.1 |
| Streptococcus agalactiae | 1875 | 2.1 | 6.2 | 1707 | 3.9 | 91.0 |
| Streptococcus uberis | 2212 | 2.5 | 7.3 | 1856 | 4.3 | 83.9 |
| Streptococcus dysgalactiae | 964 | 1.1 | 3.2 | 924 | 2.1 | 95.9 |
| Major Gram-positive pathogens | 11 138 | 12.4 | 36.6 | 9898 | 22.7 | 88.9 |
| Escherichia coli | 141 | 0.2 | 0.5 | 128 | 0.3 | 90.8 |
| Klebsiella pneumonia | 45 | 0.1 | 0.2 | 42 | 0.1 | 93.3 |
| Serratia spp. | 102 | 0.1 | 0.3 | 99 | 0.2 | 97.1 |
| Major Gram-negative pathogens | 288 | 0.3 | 1.0 | 269 | 0.6 | 93.4 |
| All major pathogens | 11 426 | 12.8 | 37.6 | 10 167 | 23.3 | 89.0 |
| Staphylococcus pseudintermedius | 445 | 0.5 | 1.5 | 237 | 0.5 | 53.3 |
| Coagulase-negative staphylococci | 17 249 | 19.2 | 56.7 | 10 352 | 23.7 | 60.0 |
| Streptococcus pyogenes | 56 | 0.1 | 0.2 | 53 | 0.1 | 94.6 |
| Enterococcus faecalis | 651 | 0.7 | 2.1 | 557 | 1.3 | 85.6 |
| Enterococcus canis | 33 | 0.0 | 0.1 | 26 | 0.1 | 78.8 |
| Trueperella pyogenes | 19 | 0.0 | 0.1 | 16 | 0.0 | 84.2 |
| Micrococcus spp. | 141 | 0.2 | 0.5 | 104 | 0.2 | 73.8 |
| Other Gram-negative bacteria | 379 | 0.4 | 1.3 | 309 | 0.7 | 81.5 |
| All minor pathogens | 18 973 | 21.2 | 62.4 | 11 654 | 26.7 | 61.4 |
| All culture-negative samples | 59 236 | 66.1 | - | 21 876 | 50.1 | 36.9 |
| All culture-positive samples | 30 399 | 33.9 | - | 21 821 | 49.9 | 71.8 |
| All samples tested | 89 635 | - | - | 43 697 | - | 48.8 |
Source: Milk laboratory, Faculty of Veterinary Science, University of Pretoria
†
, The number of quarter milk samples, per pathogen group or species, that had a somatic cell counts of below 200 000 cells/mL expressed as a percentage of the total quarters (43 697) identified with somatic cell counts below 200 000 cells/mL.
SCC, somatic cell counts.