Evaluation of the synergistic effect of bacterial recombinant alginate lyase and therapeutic antibiotics on the growth of planktonic Pseudomonas aeruginosa

Background & Alginate is one of the most important virulence factors of Pseudomonas aeruginosa. This study aimed to evaluate the synergistic effect of recombinant alginate lyase and common antibiotics in the treatment of Pseudomonas infections on the growth of planktonic cells of P. aeruginosa.
 
Materials & In this study, P. aeruginosa TAG48 was isolated and identified from the clinical sample. To purify alginate lyase and its effect on planktonic cells, the alginate lyase gene (algL) was isolated, cloned, sequenced and expressed. The resultant enzyme was purified by affinity chromatography. The ciprofloxacin, tobramycin, and cefixime were also used to test the effectiveness of these antibiotics on planktonic cells of P. aeruginosa by carrying out MIC, MBC. The synergistic effects of these antibiotics and the recombinant alginate lyase enzyme on planktonic cells were evaluated.
 
Our results indicated that the antibiotics and the enzyme have shown MIC for ciprofloxacin, tobramycin, cefixime and enzyme in the following concentrations: 4, 16,128 and 9.37 μg/ml, respectively. MBC was also calculated equal to MIC. Also, alginate lyase exhibited synergy with tobramycin and cefixime on the growth of planktonic cells of P. aeruginosa TAG48 but not with ciprofloxacin.
 
Regarding the importance of alginate in the pathogenicity of P. aeruginosa, its degradation could reduce this characteristic of the bacteria. Detection of novel algL genes in bacterial communities can also lead the way for the study of alginate lyases with specific activities against alginates from pathogenic bacteria in microbial samples.