Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) for Typing Pseudomonas Aeruginosa Isolated from Urine Samples of Different Patients

Pseudomonas aeruginosa is considered as one of the important causes of urinary infections in hospitals. The aim of the current study is the genetic typing for the number of bacterial strains isolated from patients using MLVA technique.
In this study, 70 isolates were collected from different hospitals located in Tehran city. First, DNA extraction was conducted for genotyping analysis by MLVA method. Subsequently, VNTR sequences located in several genes of bacterial genomes such as MS-214, MS-215, MS-217, MS-222, MS-223, MS-142 and MS-173 were amplified by specific primers using PCR technique. After confirming the PCR amplification using electrophoresis and visualization of their bonds on agarose gel, relationship evolutionary graph for the different strains was constructed based on MLVA technique.
FINDINGS: After the electrophoresis and determination of VNTR copy-numbers, 70 strains were classified as 36 types. The genetic evolutionary tree was also constructed based on VNTRs Data. According to the results, PCR products of 70 strains visualized by electrophoresis are divided to 39 types based on VNTR analysis. Evolution tree and MSR algorithm was also constructed for all 70 clinical isolates. According to the MST algorithm, 70 clinical strains divided into 11 clonal complexes which these criteria is interpreted as genetic distance based on the difference of VNTR copy numbers for each group
The present study showed that MLVA could be helpful for typing clinical strains of P. aeruginosa. The results also showed that this method had great potential to differentiate those strains with high phenotypic similarity.