Genotyping of Pseudomonas aeruginosa strains isolated from burn patients by RAPD-PCR.

BACKGROUND

Pseudomonas aeruginosa is one of the important causes of nosocomial infections that easily gains resistance to many antibiotics. This opportunistic pathogen is a major health hazard particularly in immunodeficient patients, patients in intensive care units (ICU) and burn units with life threatening outcome. The bacterium may be originated from different or common sources, and comprises a high colonization and transmission capacity.

OBJECTIVE

The aim of present study was to investigate the genotypic variation of Pseudomonas aeroginosa strains isolated from burn patients by using Random Amplified Polymorphic DNA (RAPD) method.

METHODS

Totally 70 clinical samples were collected from burn patients in Taleghani Burn Hospital of Ahvaz. Fifty out of total samples were positive for P. aeruginosa by application of conventional culture and biochemical identification tests. DNA was extracted from the isolates and the RAPD-PCR method was applied to the DNA extracts according to standard method using a short single primer of 272. The technique created repetitive electrophoresis patterns which was used for genotypic differentiation.

RESULTS

RAPD-PCR, created 9 genotypic profiles designated as I-IX with base pair length ranging from 180 to 2700. Each genotype showed between 3 and 6 different weight DNA bands. Genotype I was the most prevalent, identified in 10 bacterial isolates (20%). Genotypes I, II and VI were mostly common in patients with more severe burn, and were mainly isolated from wound and blood samples obtained from the same patients.

CONCLUSION

In present study, we found RAPD-PCR technique as a useful tool for investigation of the genetic variation among P. aeruginosa strains. This is a rapid, low cost, genotypic method with high discriminatory power. The results could assist to screen for the original of infection caused by this organism with subsequent control of colonization and transmission.