Table 3.
Distribution of the main virulence genes among the toxinogenic and non toxinogenic S. aureus (excluded PVL +) isolated from different ecological niches in Algeria.
| Virulence and Resistance Genes | TSST-1 + no. (%) |
Et + no. (%) |
Non Toxinogenic MSSA no. (%) |
p valuea |
|---|---|---|---|---|
| Isolates | n = 62 | n = 33 | n = 203 | |
| Enterotoxins | ||||
| sea | 36 (58.0) | 26 (78.7) | 115 (56.6) | NS |
| seb | 7 (11.2) | 2 (6.0) | 14 (6.8) | NS |
| seg | 43 (69.3) | 30 (90.9) | 38 (18.7) | < 0.001 |
| seh | 18 (29.0) | 0 (0) | 16 (7.8) | 0.001 |
| sei | 62 (100) | 32 (96.9) | 179 (88.1) | NS |
| sek | 13 (20.9) | 2 (6.0) | 20 (9.8) | NS |
| seq | 13 (20.9) | 2 (6.0) | 16 (7.8) | NS |
| Other Toxins | ||||
| tst | 62 (100) | 6 (18.1) | 0 (0) | < 0.001 |
| etA | 2 (3.2) | 8 (24.2) | 0 (0) | < 0.001 |
| etB | 4 (6.4) | 25 (75.7) | 0 (0) | < 0.001 |
| etD | 0 (0) | 0 (0) | 0 (0) | NS |
| edinA | 0 (0) | 0 (0) | 0 (0) | NS |
| edinB | 24 (38.7) | 1 (3.0) | 18 (8.8) | < 0.001 |
| Leukocidins | ||||
| lukD | 62 (100) | 33 (100) | 203 (100) | NS |
| lukE | 62 (100) | 33 (100) | 203 (100) | NS |
| Hemolysins | ||||
| hla | 55 (88.7) | 33 (100) | 191 (94.0) | NS |
| hlb | 24 (38.7) | 1 (3.0) | 43 (21.1) | NS |
| hld | 62 (100) | 33 (100) | 203 (100) | NS |
| hlgA | 49 (79.0) | 33 (100) | 188 (92.6) | NS |
| hlgv | 60 (96.7) | 32 (96.9) | 197 (97.0) | NS |
| MSCRAMMs | ||||
| bbp | 62 (100) | 33 (100) | 203 (100) | NS |
| clfA | 62 (100) | 33 (100) | 203 (100) | NS |
| clfB | 62 (100) | 33 (100) | 203 (100) | NS |
| cna | 0 (0) | 0 (0) | 14 (6.8) | 0.006 |
| ebpS | 62 (100) | 33 (100) | 203 (100) | NS |
| fib | 55 (88.7) | 32 (96.9) | 187 (92.1) | NS |
| fnbA | 10 (16.1) | 7 (21.2) | 26 (12.8) | NS |
| fnbB | 28 (45.1) | 6 (18.1) | 62 (30.5) | NS |
| Capsule Components | ||||
| cap5 | 35 (56.5) | 20 (60.6) | 138 (68.0) | NS |
| cap8 | 27 (44.5) | 13 (39.4) | 65 (32.0) | NS |
| Intracellular Adhesion Polysaccharide | ||||
| icaA | 62 (100) | 33 (100) | 203 (100) | NS |
| icaC | 62 (100) | 33 (100) | 203 (100) | NS |
| icaD | 62 (100) | 33 (100) | 203 (100) | NS |
| Other | ||||
| ACME clusterb | 0 (0) | 0 (0) | 0 (0) | NS |
| Accessory Gene Regulators | ||||
| agr1 | 42 (67.7) | 25 (75.7) | 153 (75.3) | NS |
| agr2 | 6 (9.6) | 3 (9.0) | 31 (15.2) | NS |
| agr3 | 14 (22.5) | 2 (6.0) | 19 (9.3) | NS |
| agr4 | 0 (0) | 3 (9.0) | 0 (0) | NS |
ap value corresponds to comparison between toxinogenic and non toxinogenic S. aureus isolates using Fisher exact test. b ACME (arginine catabolic mobile element) includes the arc genes (arcA to arcD) and the oligopeptide permease operon genes (opp-3A to opp-3E). NS, not significant (p > 0.05).