Genetic relatedness of multidrug-resistant <i>Pseudomonas aeruginosa</i> from patients in tertiary hospitals in southwest Nigeria

Pseudomonas aeruginosa, one of the deadliest bacterial diseases, has intrinsic multidrug antibiotic resistance.The genetic diversity of multidrug-resistant (MDR) P. aeruginosa in Nigeria has not been fully explored, which makes it expedient to characterize and determine its relatedness.Six hundred clinical samples were obtained aseptically from the Federal Medical Center, Abeokuta, the University of Medical Sciences, and Lagos University Teaching Hospital.These samples were grown on MacConkey, Blood, and Cetrimide agars.Biochemical characterization and 16S rRNA sequencing were used to identify isolates of P. aeruginosa.The disc diffusion method was used to conduct antibiotic sensitivity tests.Alkali-lysis was used to extract plasmids from MDR P. aeruginosa isolates, which were then electrophoresed and allowed to cure.To ascertain the genetic relationships among P. aeruginosa isolates, genomic DNA was taken from the isolates and amplified using the pulsed-field gel electrophoresis (PFGE), following a standardized protocol adapted from the Centers for Disease Control and Prevention.Of the 360 bacterial isolates identified, 11.3% are P. aeruginosa, and all are resistant to ampicillin and cloxacillin.After curing, 14 (60.9%) of the MDR strains were plasmid-mediated.The fourteen plasmid-mediated P. aeruginosa-relatedness were found to be in clusters A, B, C and D. Two P. aeruginosa isolates in cluster A and cluster D, with 80% similarity, were from University of Medical Sciences and Federal Medical Center.Six plasmid-mediated P. aeruginosa isolates in cluster B had different similarities, which ranged from 60% to 80%, while 4 strains in cluster C were isolated from samples in all tertiary hospitals with 60% to 70% similarity.