Cyclic AMP and biofilms reveal the synergistic proliferation strategy of Pseudomonas aeruginosa and Escherichia coli under the costimulation of high concentrations of microplastics and enrofloxacin

• Published in: The Science of the total environment Vol. 838; no. Pt 3; p. 156470
• Main Authors: Wu, Rui-Ting, Chen, Jing-Yuan, Liu, Shuo, Niu, Shi-Hua, Liao, Xin-Di, Xing, Si-Cheng
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 10.09.2022
• Subjects: Biofilm; Cyclic AMP; Enrofloxacin; Microplastic; Synergy survival; Biofilm; Cyclic AMP; Synergy survival; Microplastic; Enrofloxacin
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.156470

Microplastics (MPs) provide attachment sites for biofilm formation of microorganisms, which can promote their resistance to environmental stress has been proved. However, the effect of MPs on synergy survival among microorganisms under antibiotic stress remains unclear. In the present study, the proliferation of Escherichia coli and Pseudomonas aeruginosa was assessed under enrofloxacin stress with the influence of MPs. Here, MPs reduced the growth speed of E. coli and enhanced that of P. aeruginosa, especially at 12 h, but the final value of OD600 and CFU of both bacteria not be influenced. E. coli was enrofloxacin sensitive (MIC = 0.25 μg/mL), and a high MP concentration in the presence of enrofloxacin notably enhanced the biofilm formation ability of P. aeruginosa, but proliferation decreased. In the coculture system, the proliferation of E. coli (increased 1.42-fold) and P. aeruginosa (increased 1.06-fold) both increased under enrofloxacin stress (0.25 μg/mL) with high-concentration MP addition. P. aeruginosa may provide the biofilm matrix for E. coli to resist the stress of enrofloxacin. The high concentration of cyclic AMP secreted by E. coli may slightly inhibited biofilm formation, leading to a decrease in the fitness cost of P. aeruginosa; thus, the proliferation of P. aeruginosa increased. The present study is the first to show that MP combined with antibiotics stimulates the metabolic cooperation of bacteria to promote proliferation. [Display omitted] •Microplastic reduced the growth speed of E. coli and enhanced it for P. aeruginosa.•High concentration microplastic combined enrofloxacin caused fitness cost of P. aeruginosa•Co-culture promoted proliferation of two strains under co-stimulation of microplastic and enrofloxacin.•Co-culture promoted proliferation of E. coli by the biofilm protection of P. aeruginosa.•Co-culture decreased fitness cost of P. aeruginosa by cyclic AMP secretion of E. coli.