Plasmid Profile Analysis of Pseudomonas aeruginosa Isolated from Wound Infections in a General Hospital in Southern Nigeria

Background/Purpose: Open wound infection is a serious problem especially with extended-spectrum beta lactamase (ESBL) producing Gram negative bacteria such as P. aeruginosa. The purpose of this research was to identify open wound infections due to Pseudomonas aeruginosa and also determine their plasmid profile.

Methods: A total of 50 Pseudomonas aeruginosa isolates were obtained from clinical wound swabs in a secondary health care facility. Pseudomonas aeruginosa isolates were identified using Microbact 24E system kit. Pseudomonas aeruginosa were isolated and subjected to antibiotic susceptibility testing by disc diffusion method. ESBL production was detected using Double Disk Synergy Test (DDST) and CHROMagar ESBL (France). Six different antibiotic discs were used to determine the susceptibility pattern of the isolates. Plasmids were extracted using ZR plasmid Miniprep classic extraction Kit. Electrophoresis of the DNA was carried out on 0.8% w/v agarose gel.

Results: The prevalence of Pseudomonas aeruginosa was 63%. The antibiotic resistance pattern showed that Pseudomonas aeruginosa was highly resistant against cefotaxime (90%), ofloxacin (80%), ceftazidime (55%), azetronam (60%), imipenem (25%), amoxicillin clavulanic acid (35%) and amikacin (30%). Plasmid profile was carried out on 20 selected multidrug resistant isolates; those resistant to three or more classes of antibiotics. Plasmid content of the isolates were found to be 90%. All isolates that had plasmid were resistant to cefotaxim, ceftazidime, azetronam, ofloxacin and amikacin.

Conclusion: Antibiotic resistance by P. aeruginosa is increasingly high in wound infections and appears to be linked to the presence of plasmid and ESBL enzymes.