ELECTRONMICROSCOPIC INVESTIGATION OF THE EFFECTS OF BIOCIDES ON PSEUDOMONAS-AERUGINOSA PA0 BACTERIOPHAGE-F116

Electronmicroscopy was used to observe morphological changes of the Pseudomonas aeruginosa PA0 bacteriophage F116 when treated with various biocides commonly used as antibacterial and antifungal agents. Because of its large size (145 nm) and its organised structure (an isometric head and a tail), it was possible to classify structural damage into eight categories. The morphological changes induced depended on the type of biocide used and its concentration. Glutaraldehyde increased the number of phages with empty heads. Peracetic acid and phenol altered the appearance of the viral genome packaged inside the head, produced fractured heads, and damaged the tail. Peracetic acid also induced folding of the phage heads. The alcohols tested also altered the head structure. Cetylpyridinium chloride induced mainly fractured head damage. Chlorhexidine had little effect on the structure of F116.