Detection and association of toxA gene with antibiotics resistance in Pseudomonas aeruginosa strains isolated from different sources in Al Muthanna city

Abstract

IntroductionExotoxin A (ETA) is a powerful chromosomal extracellular virulence factor produced by most of clinical P. aeruginosa isolates. P. aeruginosa is the most common respiratory pathogen in patients with cystic fibrosis (CF). PurposeIn this study, the Pseudomonas aeruginosa strains were isolated from patient's different sources and screened against the toxA gene in order to identify the association between the increase of antibiotics resistance and the toxin production. Methods and resultsOne hundred samples were collected from different cases included: 25 swabs otitis infection, 25 samples from urinary tract infections and 25 swabs from each wound and burn infections for isolation of P. aeruginosa and detection of toxA gene in during the period between July 2019 to January 2020. These samples were cultured firstly onto the Brain heart infusion for 24 h 37oC, followed by the re-streak single colony on the selective on chrome agar media and incubated for 18–24 h at 37oC. The P. aeruginosa isolates were confirmed isolation using VITEK-2 Compact system.The isolation percentage of P. aeruginosa was 80% in the total sample were collected. The highest percentage isolation of P. aeruginosa was from otitis infection at (92%), followed by in wound and burn was (80%), and urinary tract infection was (72%). The gDNA of these isolated was extracted and then subject to PCR technique, detection of the toxA gene as a chromosomal target for the P. aeruginosa infection. The toxA gene detection percentage was (35%) in all the P. aeruginosa isolates; the highest toxA amplification was among strains isolated from otitis at the percentage of 59%, followed by 27% among the strains isolated from urine and 25% of the strains isolated from each wound and burn infections. These isolates were tested against the antibiotic resistance showed the highest percentage of the resistance level, especially those strain associated with detection of toxA gene-positive PCR product. However, the meropenem showed the highest effect against all of P. aeruginosa except for six showed higher resistance than other strains. The PCR product of the strains among the toxA detection was digested with FoKI, yielding two-band at 152 bp and 118 bp, unless those strains resisted the meropenem were showed uncut PCR product by the FoKI, showing polymorphism in the toxA gene in those strains.