Mechanism Underlying the Role of LuxR Family Transcriptional Regulator abaR in Biofilm Formation by Acinetobacter baumannii

Sun, Xu; Xiang, Jun

doi:10.1007/s00284-021-02654-y

Cited by 4 publications

(1 citation statement)

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“…The only reported QS-system in A. baumannii is AbaI/R which closely regulates various virulence factors including biofilm formation. It is reported that abaI mutants were less virulent than wild type and an AbaR mutant formed lesser biofilms comparatively [77,78]. Therefore, we screened the effect of 2,4-DBP on abaI and abaR expression.…”

Section: Discussionmentioning

confidence: 99%

In vitro and in silico assessment of anti-biofilm and anti-quorum sensing properties of 2,4-Di-tert butylphenol against Acinetobacter baumannii

Jha,

Gopu,

Sivasankar

et al. 2024

Journal of Medical Microbiology

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Introduction. Acinetobacter baumannii is a nosocomial pathogen with a high potential to cause food-borne infections. It is designated as a critical pathogen by the World Health Organization due to its multi-drug resistance and mortalities reported. Biofilm governs major virulence factors, which promotes drug resistance in A. baumannii. Thus, a compound with minimum selection pressure on the pathogen can be helpful to breach biofilm-related virulence. Hypothesis/Gap Statement. To identify anti-biofilm and anti-virulent metabolites from extracts of wild Mangifera indica (mango) brine pickle bacteria that diminishes pathogenesis and resistance of A. baumannii. Aim. This study reports anti-biofilm and anti-quorum sensing (QS) efficacy of secondary metabolites from bacterial isolates of fermented food origin. Method. Cell-free supernatants (CFS) of 13 bacterial isolates from fermented mango brine pickles were screened for their efficiency in inhibiting biofilm formation and GC-MS was used to identify its metabolites. Anti-biofilm metabolite was tested on early and mature biofilms, pellicle formation, extra polymeric substances (EPS), cellular adherence, motility and resistance of A. baumannii. Gene expression and in silico studies were also carried out to validate the compounds efficacy. Results. CFS of TMP6b identified as Bacillus vallismortis, inhibited biofilm production (83.02 %). Of these, major compound was identified as 2,4-Di-tert-butyl phenol (2,4-DBP). At sub-lethal concentrations, 2,4-DBP disrupted both early and mature biofilm formation. Treatment with 2,4-DBP destructed in situ biofilm formed on glass and plastic. In addition, key virulence traits like pellicle (77.5 %), surfactant (95.3 %), EPS production (3-fold) and cell adherence (65.55 %) reduced significantly. A. baumannii cells treated with 2,4-DBP showed enhanced sensitivity towards antibiotics, oxide radicals and blood cells. Expression of biofilm-concomitant virulence genes like csuA/B, pgaC, pgaA, bap, bfmR, katE and ompA along with QS genes abaI, abaR significantly decreased. The in silico studies further validated the higher binding affinity of 2,4-DBP to the AbaR protein than the cognate ligand molecule. Conclusion. To our knowledge, this is the first report to demonstrate 2,4- DBP has anti-pathogenic potential alone and with antibiotics by in vitro, and in silico studies against A. baumannii. It also indicates its potential use in therapeutics and bio-preservatives.

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Section: Discussionmentioning

confidence: 99%