Relationship between quorum-sensing and virulence genes of Pseudomonas aeruginosa isolated from patients, and their association with antimicrobial resistance

Abstract

Background: Zoonotic diseases are illnesses that humans can contract from animals and vice versa. Pseudomonas aeruginosa is an opportunistic organism that makes treating infections challenging, particularly in individuals with underlying medical conditions and those with impaired immune systems. The increasing number of multidrug-resistant forms of Pseudomonas aeruginosa poses a serious threat to public health. Aim: This study examined the frequency of two virulence genes and two quorum sensing genes. Methods: 100 samples (50 urine, 25 wound infections, and 25 burns) were collected from Medical City Hospitals in Baghdad, Iraq, during the period (October 2023- February 2024). Determination of isolates was made according to colony features, Gram staining techniques, standard biochemical responses, and confirmed by 16s rRNA gene. Some of the virulence factor genes (ExoS and lasB), and quorum sensing genes (LasR and rhlR) genes were examined using specific primers with the aid of polymerase chain reaction (PCR). Then, the biofilm production test and antibiotic sensitivity test performed were conducted on these isolates using the microtiter plate method. Results: A total of 17 (17%) obtained from (urine, burns, and wound infections). The isolates included 2(40.00%) for the ExoS gene, 3(60.00%) for the lasB gene, 2(60.00%), 3(40.00%), for LasR, and rhlR, genes respectively. The result showed that all the isolates 17(100%) produced biofilm, revealed that 60% of P. aeruginosa isolates were strong biofilm producers, while 30% and 10 % of the isolates were moderate and weak producers, respectively. and gives a result that the isolates of P. aeruginosa resist Meropenem, Ceftazidime, and Nalidixic 17(100%), while was sensitive to Gentamicin 8(74.0%), Amikacin 7(41.1%), Piperacillin 15(88.2%), Ciprofloxacin and Levofloxacin 13(76.4%). Conclusion: Human isolates exhibit a higher prevalence of virulence genes, specifically ExoS (20%) and IasB (40%), relative to isolates from pet birds. Furthermore, human isolates demonstrate a greater prevalence of quorum sensing genes, with LasR at 40% and rhlR at 60%, compared to pet bird isolates. Biofilm production among isolates obtained from human and pet bird sources was categorized as follows: 59.3% demonstrated strong production, 28.1% exhibited moderate production, and 12.5% displayed weak production.