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Abstract：
Pseudomonas aeruginosa is one of the top-listed pathogens in nosocomial infection. It is notorious for its complicated virulence system and rapid adaptability to drugs or antimicrobials. In this study, we aimed to evaluate the prevalence of sixteen virulence genes in four groups including type III secretion system, biofilm formation, extracellular toxin biosynthesis and enzymes amongst 209 clinical Pseudomonas aeruginosa strains. We investigated the different distribution patterns of virulence genotypes based on carbapenem-resistant phenotype or the carriage of carbapenemase genes. The detection rate of each virulence gene varied greatly. phzM and plcN were detected in all collected strains, while pilB and exoU were only carried by a small portion of isolates (6.7% and 16.3%). Additionally, the number of genotypes observed in each group of examined virulence genes ranged from 4 to 8. Only the distribution of genotypes of type III secretion system showed statistical difference between carbapenem-mediated or carbapenem-resistant and carbapenem-sensitive strains. The virulence genotype of Pseudomonas aeruginosa was possibly interrelated to its resistance mechanism. Further research suggested that one particular TTSS genotype exhibited higher ratio in carbapenemase-producing strains and exoS was less frequently detected in CRPA strains carrying carbapenemase gene. Generally, the significant genetic diversity of virulence genes amongst Pseudomonas aeruginosa strains was highlighted in this study. Specific TTSS genotypes were associated with carbapenem-resistance. In particular, certain incompatibility might exist between exoS and carbapenemase genes, which provided valuable information for further understanding the relationship between carbapenem resistance and virulence.
摘要：
铜绿假单胞菌是医院感染的首选病原菌之一。它以其复杂的毒力系统和对药物或抗菌剂的快速适应性而臭名昭著。在这项研究中,我们的目的是评估16个毒力基因在四组中的流行，包括III型分泌系统，生物膜的形成，209个临床铜绿假单胞菌菌株的胞外毒素生物合成和酶。我们研究了基于碳青霉烯类耐药表型或碳青霉烯酶基因携带的毒力基因型的不同分布模式。各毒力基因的检出率差异较大。在所有收集的菌株中检测到phzM和plcN，而pilB和exoU仅由一小部分分离株携带(6.7%和16.3%)。此外,在每组检查的毒力基因中观察到的基因型数量为4至8。只有III型分泌系统的基因型分布在碳青霉烯介导的或碳青霉烯抗性和碳青霉烯敏感性菌株之间显示出统计学差异。铜绿假单胞菌的毒力基因型可能与其耐药机制有关。进一步的研究表明，一种特定的TTSS基因型在产生碳青霉烯酶的菌株中表现出较高的比率，而在携带碳青霉烯酶基因的CRPA菌株中检测到exoss的频率较低。一般来说,本研究强调了铜绿假单胞菌毒力基因的显著遗传多样性。特定TTSS基因型与碳青霉烯类耐药相关。特别是,exoS和碳青霉烯酶基因之间可能存在某些不相容性，这为进一步了解碳青霉烯耐药性与毒力的关系提供了有价值的信息。
