Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran,.
Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Infect Genet Evol. 2020 Nov;85:104509. doi: 10.1016/j.meegid.2020.104509. Epub 2020 Aug 21.
The cooperation of Pseudomonas aeruginosa and Staphylococcus aureus in various infections results in increased pathogenicity and antibiotic resistance. However, the mechanism controlling such a phenomenon is still unclear. In this study, the effects of S. aureus on the metabolism, antibiotic resistance, and pathogenicity of P. aeruginosa were investigated.
The biofilm and the planktonic states of growth of P. aeruginosa and S. aureus were investigated using the co-culture method in the L929 cell line. Then, the antibiotic resistance and virulence factors production of the recovered colonies of P. aeruginosa were examined by phenotypic methods. Quantitative Real-Time PCR was used to determine the expression level of crc, lasI/R, and rhlI/R genes. Two way ANOVA test and student's t-test were used to analyze the effect of S.aureus on metabolism, virulence, and resistance of P.aeruginosa.
P. aeruginosa strains in a single-species planktonic culture on the L929 cell line indicated higher CFU counts than the biofilm. Conversely, in the biofilm state of co-culture, the CFU counts increased in comparison to the planktonic condition. Also, the expression level of crc increased two fold in the PA-1 and PA-2 strains compared to the single-species cultures on the L929 cell line. However, the PA-3 strain indicated a sharp decrease in the expression of crc (3 fold decrease). Besides, a 3-4 fold increase in susceptibility to amikacin was observed as the expression level of crc declined. The QS-regulated factors were diminished as rhlR and lasI were downregulated in both states of growth.
In polymicrobial wound infection, Staphylococcus aureus plays a vital role in the metabolic changes of Pseudomonas aeruginosa. However, the levels of antibiotic susceptibility and pathogenicity of Pseudomonas aeruginosa also changed due to metabolism.
铜绿假单胞菌和金黄色葡萄球菌在各种感染中的合作导致了致病性和抗生素耐药性的增加。然而，控制这种现象的机制仍不清楚。在本研究中，研究了金黄色葡萄球菌对铜绿假单胞菌代谢、抗生素耐药性和致病性的影响。
采用共培养法在 L929 细胞系中研究铜绿假单胞菌和金黄色葡萄球菌的生物膜和浮游生长状态。然后，通过表型方法检测恢复的铜绿假单胞菌菌落的抗生素耐药性和毒力因子产生情况。采用定量实时 PCR 法检测 crc、lasI/R 和 rhlI/R 基因的表达水平。采用双向方差分析和学生 t 检验分析金黄色葡萄球菌对铜绿假单胞菌代谢、毒力和耐药性的影响。
在 L929 细胞系上的单一浮游培养物中，铜绿假单胞菌菌株的 CFU 计数高于生物膜。相反，在共培养的生物膜状态下，CFU 计数比浮游状态增加。此外，与在 L929 细胞系上的单一物种培养物相比，PA-1 和 PA-2 菌株的 crc 表达水平增加了两倍。然而，PA-3 菌株的 crc 表达水平急剧下降（下降 3 倍）。此外，当 crc 的表达水平下降时，对阿米卡星的敏感性增加了 3-4 倍。在两种生长状态下，rhlR 和 lasI 的下调导致 QS 调节因子减少。
在多微生物伤口感染中，金黄色葡萄球菌在铜绿假单胞菌的代谢变化中起着至关重要的作用。然而，由于代谢的变化，铜绿假单胞菌的抗生素敏感性和致病性水平也发生了变化。
