Amplification of tox A, exo S and exo T genes of P. aeruginosa at 396bp, 118 bp and 152 bp respectively, by multiplex PCR. Lane L: 100 bp DNA ladder; Lane 3–5 positive samples for exoT at 152 bp; and 1-5 for toxA genes at 396 bp with no detection of exoS; Lane N: control negative; Lane P: control positive.