Quorum Sensing and Genetic Lineages in Carbapenem-Resistant <i>Pseudomonas aeruginosa</i>

Abstract

Background: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) has become a major global concern. Quorum sensing (QS) regulates the expression of biofilm formation genes and virulence factors. Enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) is widely used in epidemiological molecular studies. Objectives: The purpose of the present study was to determine the QS characteristics and genetic relatedness of CRPA. Methods: A total of 57 non-duplicative CRPA isolates were collected. A microtiter plate assay was used to assess biofilm formation. After DNA extraction, PCR was performed to detect resistance elements and QS-encoded genes. Enterobacterial repetitive intergenic ERIC-PCR was conducted using specific primers. Results: The biofilm formation assay revealed that 10.5%, 19.3%, and 70.2% of isolates formed weak, moderate, and strong biofilms, respectively. Of the isolates, 75.4%, 64.9%, 12.3%, and 8.7% carried the blaIMP, blaVIM, blaNDM, and blaKPC genes, respectively. Additionally, 73.7%, 7.0%, and 1.7% of CRPA isolates carried the blaOXA-48-like, blaOXA-23-like, and blaOXA-20/40-like genes, respectively. The prevalence of the lasR, lasI, rhlI, rhlR, aprR, aprA, and rhlAB genes were 100%, 96.5%, 92.9%, 89.5%, 84.2%, 73.6%, and 63.2%, respectively. Enterobacterial repetitive intergenic ERIC-PCR revealed eight distinct clusters (A, B, C, D, E, F, G, and H) using a similarity cut-off of ≥ 60%. Conclusions: The findings indicate a high prevalence of strong biofilm formation and quorum-sensing genes among CRPA isolates. The study highlights the importance of biofilm production and genetic diversity in CRPA isolates, underscoring the challenges in infection control and treatment strategies.