Molecular characterization of virulence and resistance determinants in clinical Pseudomonas aeruginosa isolates: a cross-sectional analysis of virulence-resistance associations.

内容摘要

Pseudomonas aeruginosa is a clinically significant opportunistic pathogen characterized by intrinsic and acquired resistance mechanisms coupled with a diverse array of virulence determinants. This study investigated the distribution of P. aeruginosa in various clinical specimens (n&#x2009;=&#x2009;382), its virulence genes, antimicrobial resistance patterns, and associations with total resistant P. aeruginosa (TRPA) phenotypes. The majority of isolates were recovered from sputum (24.3%) and endotracheal tube samples (22.5%). Virulence gene screening revealed moderate-to-high prevalence of lasB (55.0%), toxA (49.7%), pilA (53.7%), aprA (56.5%), phzS (45.0%), exoS (41.9%), and exoU (38.0%), indicating their widespread involvement in pathogenicity. Antimicrobial susceptibility profiling demonstrated the highest susceptibility to amikacin (56.3%) and gentamicin (52.4%), while resistance to carbapenems (imipenem 52.4%, meropenem 52.9%) and cephalosporins was alarmingly high. Based on resistance classification, 33.5% of isolates were MDR, and 9.7% XDR. Among ceftazidime-resistant isolates (n&#x2009;=&#x2009;200), 83% harboured ESBL genes, with blaCTX-M (38.0%) being most prevalent. Notably, 30.7% and 22.8% of isolates carried blaNDM-1 and blaOXA-48, respectively. Comparative analysis demonstrated statistically significant associations between TRPA phenotype and virulence genes: lasB (OR&#x2009;=&#x2009;90.3), toxA (OR&#x2009;=&#x2009;260.9), and pilA (OR&#x2009;=&#x2009;32.6) (p&#x2009;<&#x2009;0.0001). Resistance determinants such as blaCTX-M (OR&#x2009;=&#x2009;3.5), aac(6')-Ib (OR&#x2009;=&#x2009;2.9), qnrA (OR&#x2009;=&#x2009;3.9), and co-carriage of NDM-1&#x2009;+&#x2009;OXA-48 (OR&#x2009;=&#x2009;4.9) were significantly enriched in TRPA isolates. These findings demonstrate a significant association between virulence and antimicrobial resistance traits, emphasizing the potential expansion of high-risk P. aeruginosa clones in clinical settings and highlighting the need for genomic surveillance and antimicrobial stewardship interventions.