Genetic representation of oprD gene. (a) Nucleotide alignment of oprD gene and (b) protein alignment of oprD gene. For Pseudomonas aeruginosa PA-3, PA-16 and PA-6, large deletion of ten nucleotides from position 209 to 218 led to premature stop codon TGA in oprD, resulting in truncated polypeptide made of 90 aa residues. For P. aeruginosa PA-4, C to T substitution in nucleotide position 88 led to premature stop codon TAG in oprD, resulting in truncated polypeptide made of 29 aa residues.