Expression of cupA gene cluster responsible for biofilm formation in Pseudomonas aeruginosa is enhanced against subinhibitory concentration of carbapenems

• Published in: Gene reports 2022-03, Vol.26, p.101427, Article 101427
• Main Authors: Deshamukhya, Chandrayee, Saikia, Ranjan, Das, Bhaskar Jyoti, Paul, Deepjyoti, (Chanda), Debadatta Dhar, Bhattacharjee, Amitabha
• Format: Article
• Language: English
• Subjects: Biofilm; Carbapenem; cupA; Pseudomonas aeruginosa
• ISSN: 2452-0144; 2452-0144
• DOI: 10.1016/j.genrep.2021.101427

Pseudomonas aeruginosa, an opportunistic pathogen, is a potent biofilm forming organism. Independent of the type IV pili, the cupA cluster in Pseudomonas aeruginosa facilitates biofilm formation which provides protection against antibacterial treatment. The pel and psl genes synthesizing exopolysaccharides also initiate biofilm formation. Investigations revealed antibiotic exposure to be associated with modulated expression of many resistance genes in different species of bacteria depending upon the concentrations in which these are used. In recent days, the use of carbapenems, is growing at an alarming rate to treat infections and may also have a regulatory effect in the expression of cupA, pslA and pelA genes associated with biofilm formation. The present study therefore was taken up to investigate the possible role of carbapenem on these gene's expression at sub lethal dose. Six carbapenem non susceptible isolates of Pseudomonas aeruginosa of clinical origin were selected for the study. The isolates were cultured upto log phase in fresh Luria Bertani broth with and without 2 μg/ml imipenem and meropenem respectively and the transcriptional response of the cupA1, cupA2, cupA3, cupA4,cupA5, pelA and pslA genes in the isolates were studied by quantitative real time PCR using the ΔΔct method. The analysis of transcriptional response of cupA1, cupA2, cupA3, cupA4,cupA5,pslA and pelA genes in the isolates revealed that the response was enhanced multiple folds under sub inhibitory concentration (2 μg/ml) imipenem and meropenem stress as compared to the response of the genes under normal growth condition i.e. without any antibiotic pressure. The present study could underscore the role of imipenem and meropenem at sub lethal dose and could infer that both imipenem and meropenem at sub lethal dose has a regulatory effect on the transcriptional response of cupA, pelA and pslA genes which are involved in biofilm formation. •Sub-inhibitory concentration of carbapenem may act as signals to enhance response of genes essential for biofilm formation•Transcriptional response of cupA genes enhanced at sub-inhibitory concentration (2 μg/ml) carbapenem•Transcriptional response of pslA and pelA genes enhanced at sub-inhibitory concentration (2 μg/ml) carbapenem