Plasmid Profile Analysis of Multidrug Resistant Pseudomonas aeruginosa Isolated from Wound Infections in South West, Nigeria

Pseudomonas aeruginosa has become increasingly recognized as an emerging opportunistic pathogen of clinical relevance. A total of 110 Pseudomonas aeruginosa was obtained from clinical wound samples in three tertiary hospitals in South West, Nigeria. Isolated pure cultures of bacteria were subjected to various morphology and biochemical tests. After which they were identified using Bergey's Manual of Systematic Bacteriology. One hundred and ten (110) Pseudomonas aeruginosa isolated from clinical wounds were subjected to antibiotic susceptibility testing by disk diffusion and plasmid profiling. Fifteen (15) different antibiotics discs were used to determine the drug sensitivity pattern of the isolates. Plasmids were extracted by the alkaline lysis method (Zymogen UK). Electrophoresis of the DNA was carried out on a 0.8% agarose gel. Variation occurred in multiple antibiotic resistance patterns among various strains of Pseudomonas aeruginosa isolated from the clinical wound samples. The antibiotic resistant pattern showed that Pseudomonas aeruginosa had high resistant to amoxicillin 92.7%, ampicillin 90%, cloxacillin 88.2%, cotrimoxazole 77.3%, erythromycin 72.7%, tetracycline 70.9%, streptomycin 65.5% and ofloxacin 60% and had low resistant to ceftazidime (20%), gentamycin (26.4%), levoxin (30.9%), ceftriaxone (34.5%) and ciprofloxacin (35.5%). Plasmid profile was carried out on 22 selected multi drug resistant (MDR) isolates that were resistant to three or more classes of antibiotics. Eight (36.4%) strains were found to possess plasmid bands. Six of the strains had single plasmid band while two strains possessed two bands with sizes ranging from 662 to 830bp. The sizes of the plasmids among P. aeruginosa isolates ranged from 662bp to 830bp. All the strains that had plasmids were resistant to amoxicillin, ampicillin, cloxacillin, cotrimoxazole, erythromycin and tetracycline.