Characterization of Uropathogenic Pseudomonas aeruginosa: Serotypes, Resistance Phenotypes, and Virulence Genotypes‏

Pseudomonas aeruginosa is a major cause of urinary tract infections. This organism has extended
resistance to antimicrobials along with multiple virulence factors, making it difficult to treat. In this
study, 49 isolates from urine samples were identified as P. aeruginosa and serotyped by the slide
agglutination method. The sensitivity of isolates against 10 antipseudomonal drugs was determined.
Phenotypically, lipase, protease, hemolysin, and biofilm production were detected. Genes for the
type III secretion system, elastase B, and exotoxin A were detected by PCR. Serotype O11 was the
most predominant serotype among test isolates. High levels of resistance were observed against
ceftazidime, cefepime, piperacillin, and piperacillin/tazobactam while 10.2% of isolates were resistant
to amikacin. MDR was detected in 20.4% of the isolates and was significantly associated with strong
biofilm producers. About 95.9% and 63.3% of P. aeruginosa isolates had proteolytic and lipolytic activity,
respectively. Among the genes detected, the exoY gene was the most prevalent gene (79.6%), while
the exoU gene was the least frequent one (10.2%). toxA and lasB genes were amplified in 63.27% and
75.5% of the isolates, respectively. In addition, the exoU gene was significantly associated with MDR
isolates. The high incidence of exoS, exoT, exoY, lasB, and toxA genes in uropathogenic P. aeruginosa
implies that these genes can be considered markers for virulent isolates. Furthermore, the coexistence
of exoU and exoS genes, even in 6% of isolates, poses a significant treatment challenge because those
isolates possess both the invasive and cytotoxic properties of both effector proteins.