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Characterization of Virulence Genes Associated with Type III Secretion System and Biofilm Formation in Pseudomonas

Afnan S B E Ali1, Batur Ozler1, Buket Baddal2,3

  • 1Department of Medical Microbiology and Clinical Microbiology, Faculty of Medicine, Near East University, 99138, Nicosia, Cyprus.

Current Microbiology
|October 25, 2023
PubMed

Insights

This study reveals that Pseudomonas aeruginosa strains in Cyprus frequently form biofilms and carry virulence genes like algD, exoT, and exoS. Most isolates exhibited multidrug resistance, highlighting a significant public health concern.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Infectious Diseases

Background:

  • Pseudomonas aeruginosa is a significant opportunistic pathogen known for its multidrug resistance (MDR) and virulence factors.
  • Factors such as antimicrobial resistance, biofilm formation, and type III secretion system (T3SS) contribute to disease severity.
  • Limited data exists on the virulence characteristics of P. aeruginosa in Cyprus.

Purpose of the Study:

  • To investigate the prevalence and distribution of virulence genes in P. aeruginosa isolates from Cyprus.
  • To assess the biofilm-forming potential of these isolates.
  • To determine the antibiotic resistance rates, including MDR and extensively drug-resistant (XDR) phenotypes.

Main Methods:

  • One hundred clinical P. aeruginosa isolates were identified using standard microbiological techniques.
  • Antimicrobial susceptibility testing was performed using the VITEK-2 system.
  • Biofilm formation was quantified via microtiter plate assay, and virulence genes (algD, exoU, exoT, exoS) were detected using PCR.

Main Results:

  • A high percentage of isolates (93%) were algD positive, and most carried T3SS genes exoT (91%) and exoS (63%).
  • The exoT+/exoS+ genotype was common (61%), while exoU was less frequent.
  • Significant biofilm-forming capacity was observed, with 35% of isolates classified as strong biofilm formers. MDR and XDR rates were 26% and 1%, respectively.

Conclusions:

  • This study provides the first molecular profiling of P. aeruginosa in Cyprus.
  • Most local strains exhibit biofilm-forming capabilities and possess key virulence genes, particularly algD, exoT, and exoS.
  • The high prevalence of antibiotic resistance underscores the need for effective infection control strategies.

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