Influence of anti-alginate serum combined with gatifloxacin on mucoid pseudomonas aeruginosa biofilm morphology.

OBJECTIVE

To investigate the influence of anti-alginate serum on morphology of biofilm (BF) of mucoid Pseudomonas aeruginosa.

METHODS

The modified plate culture method was used to establish a biofilm model of mucoid Pseudomonas aeruginosa in vitro. The biofilm was treated by anti-alginate serum and/or different concentrations of gatifloxacin. The samples were then detected by scanning electron microscopy (SEM) and optical microscopy after being stained with AgNO(3). A group of samples treated by none agent was used as blank control. The optical density of bacterial biofilm was determined by using computer image analysis system.

RESULTS

BF was achieved on the silicon slides in all groups 7 days after the incubation of Pseudomonas aeruginosa. The silicon slides were covered by dense and black stained material in the blank group; the black stained material as mildly less in the group treated with anti-alginate serum, and much less in the group treated with gatifloxacin, and the BF was thin and only slightly stained black in the group treated with anti-alginate combined with gatifloxacin. SEM showed that the mucoid materials among bacteria was reduced and the number of bacteria was decreased and the shape of bacteria became irregular in the groups treated by anti-alginate serun and/or gatiflaxacin, especially the group treated by anti-alginate combined with gatifloxacin. Computer image analysis system showed that the mean optical density was 0.82 +/- 0.06 in the blank control group, 0.79 +/- 0.06 in anti-alginate serum group, 0.76 +/- 0.07 in of gatifloxacin group, and 0.70 +/- 0.04 in anti-alginate serum combined with gatifloxacin group.

CONCLUSION

Anti-alginate serum affects the structure and morphology of the biofilm of mucoid Pseudomonas aeruginosa and destroys the biofilm structure when combined with gatifloxacin.