Antibiotic Resistance and Transfer of Extended Spectrum Beta Lactamase (ESBL) Resistant Plasmids in Pseudomonas aeruginosa Isolates from Hospitalized Patients

Abstract

The study was undertaken to determine antibiotic resistance, ESBL production and transfer of resistant plasmids of Pseudomonas aeruginosa. Clinical samples of urine, wound and blood were screened for Pseudomonas aeruginosa following standard microbiological procedures. Isolates of Pseudomonas aeruginosa were identified in a total of 110 (18.3%) samples with higher prevalence observed in wound (43.6%) and blood (40.0%) samples. Identified isolates were profiled for antimicrobial susceptibility to a total of 10 antibiotics. Plasmid DNA extraction was carried out by the alkaline lysis method. Double disc synergy test (phenotypic) and PCR (genotypic) techniques were used to determine ESBL production from selected organisms while transfer of resistant genes was assessed by conjugation using broth mating procedures. Results showed high rates of resistance among organisms tested using antipseudomonal drugs. Seventy-seven (70.0%) of the isolates were multi drug resistant (MDR), out of which 26 (33.8%) and 4 (15.4%) produced ESBL by phenotypic and genotypic methods, respectively. Plasmid profile analysis revealed that all the 77 MDR isolates harboured plasmids of > I.5 kb. Four ESBL producing isolates selected could transfer their resistance plasmid to a recipient E. coli strain K12. The therapeutic challenge observed calls for an effective antimicrobial stewardship program.