Pathogenicity of nosocomial Pseudomonas aeruginosa analyzed by pan-genomics

Abstract Pseudomonas aeruginosa is an important hospital-acquired pathogen that is usually resistant to multiple antibiotics. In 2016–2021, among the 103 strains of P. aeruginosa isolated, the age distribution of patients ranged from 10 days to 94 years with a mean age of 66.38 years. The strains isolated were from sputum (72 strains, 69.9%) and blood (14 strains, 13.6%). The size of these genomes ranged from 6.2 Mb to 7.4 Mb, with a mean value of 6.5 Mb. Besides, 20 antibiotics were selected for the determination of the drug sensitivity test. The results of antibiotic sensitivity tests showed that the isolates had the highest resistance rate of 100% to amoxicillin-clavulanate, ampicillin, ampicillin-sulbactam, cefazolin, cefotaxime, chloramphenicol, tetracycline, and trimethoprim-sulfamethoxazole. In addition to this, a total of 47 crpP genes that mediate resistance to aminoglycoside antibiotics were found distributed on 43 P. aeruginosa strains, and 10 new variants of CrpP were identified, named 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.40, 1.41 and 7.1. Whole genome analysis showed that a total of 50 ST types were identified, with ST244 (5/103) and ST1076 (4/103) having a more pronounced distribution advantage. Serotype predictions showed that O6 accounted for 29.13% (30/103), O11 for 23.30% (24/103), O2 for 18.45% (19/103), and O1 for 11.65% (12/103) of the highest proportions. Notably, we found a significantly higher proportion of ExoU in P. aeruginosa strains of serotype O11 than in other Exo-toxins strains. Our study enriches the genomic analysis of other multi-drug resistant P. aeruginosa strains, as well as the study of P. aeruginosa carrying CrpP and its variants.