Background: Pseudomonas aeruginosa an opportunistic pathogen that can infect virtually all tissues via a number of virulence factors and possess a variety of antibiotic resistance mechanisms.
The aim of this study was molecular identification of genus and species level of P. aeruginosa by detection of oprI, oprL genes respectively by PCR. Determination of antibiotic resistance profile among isolates, as well as, detection of virulence genes toxA, plcH, plcN and LasB by PCR.
Identification and antimicrobial susceptibility of fifty P. aeruginosa isolates obtained from different clinical specimens were performed on VITEK-2 Compact system. PCR was used for the molecular confirmation of genus and species level of P. aeruginosa by detection of oprI, oprL genes, as well as, the molecular detection of virulence genes toxA, plcH, plcN and LasB.
The highest prevalence of resistance was detected against 3rd and 4th generation cephalosporins (80%). Resistance to other β-lactam antibiotics including piperacillin-tazobactam, monobactams, imipenem and meropenem was 62%, 70%, 64% and 62% respectively. Resistance to aminoglycosides ranged from 44% to amikacin and 56% to tobramycin. High level of resistance (68%) to fluoroquinolones was detected. All isolates showed susceptiblity to lipopolypeptide antibiotics, colistin and polymixin. Using multiplex PCR, all strains were confirmed molecularly as P. aeruginosa via detection of oprI, oprL genes in the 50 (100%) isolates, plcH and plcN were detected in all 50 (100%) of strains and toxA in 46 (92%) and LasB in 50 (100%) of strains each in separate PCR reactions.
This investigation is a thorough report of some virulence factors and antibiotic resistance properties of P.aeruginosa isolated from Egyptian human clinical samples. Results affirm that all tox A, lasB, plcH, plcN genes are prevalent in human infections. Antibiotic resistance was high. Hence, judicious antibiotics usage is required by clinicians.