Table 3. Distribution of agr groups (alleles) and presence of virulence genes among SAB isolates from four different time periods.
Virulence gene | Gene product | Numbers of isolates with the indicated gene in each time period | Decadal changes | ||||
Agr group | 1980-81 n = 100 | 1990-91 n = 100 | 2000 n = 100 | 2010 n = 100 | IRR (95% CI)1 | p-value2 | |
agr I3 | Accessory gene regulator I | 50 | 52 | 52 | 46 | 0.98 (0.86–1.19) | 0.704 |
agr II4 | Accessory gene regulator II | 11 | 22 | 22 | 33 | 1.36 (1.12–165) | 0.002 |
agr III5 | Accessory gene regulator III | 36 | 23 | 22 | 19 | 0.81 (0.68–0.97) | 0.021 |
agr IV6 | Accessory gene regulator IV | 3 | 3 | 4 | 2 | 0.94 (0.56–1.55) | 0.796 |
Exo-polysaccharides | |||||||
cap5 | Capsular polysaccharide 5 | 46 | 24 | 11 | 28 | 0.78 (0.66–0.93) | 0.004 |
cap8 | Capsular polysaccharide 8 | 54 | 76 | 89 | 72 | 1.10 (0.99–1.22) | 0.079 |
MSCRAMMs | |||||||
cna | Collagen binding adhesin | 54 | 62 | 73 | 52 | 1.01 (0.90–1.13) | 0.885 |
sasG | S. aureus surface protein G | 29 | 36 | 28 | 50 | 1.17 (1.01–1.35) | 0.040 |
Exotoxins | |||||||
Leukocidins | |||||||
lukF, lukS, hlgA | γ-toxin | 100 | 100 | 100 | 100 | ||
lukF-PV, lukS-PV | Panton-Valentine leukotoxin | 4 | 1 | 0 | 2 | 0.75 (0.38–1.48) | 0.404 |
lukD, lukE 7 | Leukocidin D, E component | 52 | 44 | 34 | 58 | 1.02 (0.90–1.16) | 0.794 |
Haemolysins 8 | |||||||
hla | α-toxin | 80 (8)14 | 99 | 99 (1)14 | 100 | 1.04 (0.95–1.14) | 0.382 |
hld | δ-toxin | 100 | 100 | 100 | 100 | ||
Exfoliative toxins | |||||||
etA | Exfoliative toxin A | 5 | 4 | 6 | 2 | 0.85 (0.55–1.30) | 0.449 |
etB | Exfoliative toxin B | 0 | 0 | 0 | 1 | ||
etD | Exfoliative toxin D | 17 | 6 | 1 | 3 | 0.44 (0.28–0.68) | <0.001 |
Enterotoxins | |||||||
sea | Staphylococcal enterotoxin A | 32 | 20 | 13 | 19 | 0.80 (0.66–0.97) | 0.026 |
sea(N315)9 | Staphylococcal enterotoxin A, allele from N315 | 1 | 7 | 7 | 15 | 1.86 (1.28–2.69) | 0.001 |
seb | Staphylococcal enterotoxin B | 8 (2)14 | 6 (3)14 | 5 (6)14 | 6 (1)14 | 0.89 (0.63–1.27) | 0.530 |
sec+sel | Staphylococcal enterotoxin C+L | 10 | 17 | 26 | 17 | 1.19 (0.96–1.47) | 0.110 |
sed+sej+ser | Staphylococcal enterotoxin D+J+R | 15 | 9 | 4 | 4 | 0.60 (0.43–0.85) | 0.004 |
see | Staphylococcal enterotoxin E | 2 | 0 (1)14 | 0 | 0 | ||
egc-cluster 10 | Staphylococcal enterotoxin G+I+M+N+O+U | 71 | 70 | 76 | 57 | 0.95 (0.85–1.05) | 0.331 |
seh | Staphylococcal enterotoxin H | 6 | 2 | 4 | 6 | 1.05 (0.69–1.58) | 0.833 |
sek+seq | Staphylococcal enterotoxin K+Q | 2 | 3 | 1 | 8 | 1.63 (0.97–2.73) | 0.064 |
tst1 | Toxic shock syndrome toxin (TSST)-1 | 25 | 18 | 13 | 15 | 0.82 (0.66–1.01) | 0.065 |
Enzymes | |||||||
aur | Aureolysin | 100 | 100 | 100 | 100 | ||
splA 11 /splB 12 | Serine Protease A, B | 52 | 44 | 34 | 58 | 1.02 (0.90–1.16) | 0.079 |
splE | Serine Protease E | 78 | 56 | 42 | 54 | 0.86 (0.77–0.97) | 0.011 |
Miscellaneous genes | |||||||
edinB | Epidermal Cell differentiation inhibitor B | 17 | 6 | 1 | 3 | 0.44 (0.28–0.68) | <0.001 |
setC 13 | Staphylococcal exotoxin-like protein | 62 (1)14 | 66 (4)14 | 77 (1)14 | 83 (3)14 | 1.11 (1.00–1.23) | 0.050 |
Incident rate ratio estimated with Poisson regression analysis.
Poisson regression analysis.
CC6, CC7, CC8, CC20, CC22, CC25, CC45, CC59, CC97, CC101, CC182, CC188, CC395, CC398, ST2319.
CC5, CC9, CC12, CC15, CC49.
CC1, CC30, including CC30 (ST34/42).
CC50, CC121.
Three isolates in CC20 and 6 isolates in CC395 were negative for lukD, but positive for lukE; results were counted for lukE.
The haemolysin gene hlb was excluded from the analysis on the grounds of poor probe performance, which yielded several ambiguous results.
Also known as enterotoxin sep.
Seven isolates in CC50 showed a partial deletion of the egc cluster missing seg.
Locus tag SACOL1057, GenBank CP000046.1: Position 1063016–1064026.
Locus tag SACOL1056, GenBank CP000046.1: Position 1061753–1062934.
Locus tag SACOL1970, GenBank CP000046.1: Position 2034319–2035485.
Numbers in brackets show the number of ambiguous results, which were not included
Bold values are statistically significant.