Table 3.
Microbiological counts (log10 CFU/mL) using culture-dependent analysis of milk samples from healthy women (HW) and mastitis cases (MW) where growth was detected (n = 106).
| Microorganism | HW (n = 37) | MW (n = 69) | p-valuec | p-valued | ||
|---|---|---|---|---|---|---|
| n (%)a | Median (IQR)b | n (%) | Median (IQR) | |||
| Firmicutes | ||||||
| Staphylococcus epidermidis | 35 (95) | 2.50 (1.74–2.81) | 59 (85) | 5.00 (4.52–5.30) | 0.454 | 0.000* |
| Staphylococcus aureus | 3 (8) | 1.30 (1.18–1.70) | 39 (52) | 4.87 (3.84–5.30) | 0.000* | 0.007* |
| Other staphylococcie | 5 (13) | 2.30 (2.00–2.84) | 8 (12) | 3.80 (3.02–4.66) | 1.000 | 0.027* |
| Streptococcus mitis/oralis | 9 (24) | 1.84 (1.00–2.46) | 19 (27) | 4.18 (3.42–5.04) | 1.000 | 0.000* |
| Streptococcus salivarius | 4 (11) | 1.93 (1.74–2.24) | 18 (26) | 4.18 (3.70–4.70) | 0.300 | 0.005* |
| Other streptococcif | 13 (35) | 1.90 (1.30–2.08) | 12 (17) | 3.80 (3.02–4.66) | 0.315 | 0.000* |
| Enterococcus sp. | 2 (5) | 3.53 (3.23–3.71) | 3 (4) | 4.18 (4.03–4.76) | 1.000 | 0.433 |
| Other Firmicutesg | 7 (19) | 2.30 (2.04–3.06) | 6 (9) | 4.18 (3.84–4.38) | 0.454 | 0.008* |
| Proteobacteriah | 3 (8) | 3.60 (3.31–3.73) | 5 (7) | 2.60 (2.54–5.10) | 1.000 | 0.881 |
| Actinobacteria | ||||||
| Rothia mucilaginosa | 4 (11) | 1.78 (1.68–1.81) | 9 (13) | 3.78 (3.44–4.00) | 1.000 | 0.032* |
| Corynebacterium sp. | 5 (13) | 1.00 (1.00–1.30) | 9 (13) | 3.70 (3.39–4.18) | 1.000 | 0.006* |
| Other Actinobacteriai | 9 (24) | 2.36 (1.30–3.00) | 0 (0) | – | 0.000* | |
| Yeast | 2 (5) | 2.02 (1.76–2.18) | 4 (6) | 3.14 (2.84–4.15) | 1.000 | 0.157 |
| Not identified | 20 (54) | 2.41 (2.03–2.94) | 0 (0) | – | *0.000 | – |
| Total CFU | 37 (100) | 2.67 (1.60–3.18) | 69 (100) | 5.31 (5.03–5.53) | 1.000 | *0.000 |
IQR interquartile range, CFU colony-forming units.
*Statistically significant difference, p < 0.05.
an (%): number (percentage) of samples in which the microorganism was detected (relative frequency of detection).
bAll data expressed as median (IQR) log10 CFU/mL (only samples where bacterial growth was detected).
cχ2 or Fisher tests (in italics) were used to determine a possible association between breast health status and individual microorganisms or group of microorganisms isolated from milk samples. FDR-adjusted p-values.
dWilcoxon rank sum tests were used to determine if there were differences in microbiological counts between samples from HW and MW groups. FDR-adjusted p-values.
eOther staphylococcal species that were identified include S. hominis, S. lugdunensis, S. pasteuri and S. warneri.
fOther streptococcal species that were identified include S. anginosus, S. gordonii, S. parasanguinis, S. pneumoniae and S. vestibularis.
gOther Firmicutes includes Bacillus, Lactococcus, former Lactobacillus and Weisella.
hProteobacteria includes Brevundimonas, Enterobacteriaceae, Moraxella, Rhizobium and Stenotrophomonas.
iOther Actinobacteria includes Actinomyces, Bifidobacterium, Cutibacterium, Kocuria and Propionibacterium.