Association between Beta-lactam Antibiotic Resistance and Virulence Factors in AmpC Producing Clinical Strains of P. aeruginosa .

Objectives: The purpose of this study was to determine the presence of IMP and OXA genes in clinical strains of Pseudomonas aeruginosa ( P. aeruginosa ) that are carriers of the ampC gene.

Methods: In this study, 105 clinical isolates of P. aeruginosa were collected. Antibiotic resistance patterns were determined using the disk diffusion method. The strains carrying AmpC enzymes were characterized by a combination disk method. Multiplex-PCR was used to identify resistance and virulence genes, chi-square test was used to determine the relationship between variables.

Results: Among 105 isolates of P. aeruginosa , the highest antibiotic resistance was to cefotaxime and aztreonam, and the least resistance was to colictin and ceftazidime. There were 49 isolates (46.66%) that showed an AmpC phenotype. In addition, the frequencies of the resistance genes were; OXA48 gene 85.2%, OXA199, 139 3.8%, OXA23 3.8%, OXA2 66.6%, OXA10 3.8%, OXA51 85.2% and OXA58 3.8%. The IMP27 gene was detected in 9 isolates (8.57%) and the IMP3.34 was detected in 11 isolates (10.47%). Other genes detected included; lasR (17.1%), lasB (18%) and lasA (26.6%). There was a significant relationship between virulence factors and the OX and IMP genes ( p ≤ 0.05).

Conclusion: The relationship between antibiotic resistance and virulence factors observed in this study could play an important role in outbreaks associated with P. aeruginosa infections.