The effect of Ahl-1 recombinant lactonase on the resistance of Pseudomonas aeruginosa clinical isolates

Masarra M. Sakr; Khaled M. Aboshanab; Walid F. Elkhatib; Mahmoud A. Yassien; Nadia A. Hassouna

Authors

Masarra M. Sakr Microbiology and Immunology Department, Faculty of Pharmacy, Ain Shams University, PO: 11566, Cairo, Egypt.
Khaled M. Aboshanab Microbiology and Immunology Department, Faculty of Pharmacy, Ain Shams University, PO: 11566, Cairo, Egypt.
Walid F. Elkhatib Microbiology and Immunology Department, Faculty of Pharmacy, Ain Shams University, PO: 11566, Cairo, Egypt.
Mahmoud A. Yassien Microbiology and Immunology Department, Faculty of Pharmacy, Ain Shams University, PO: 11566, Cairo, Egypt.
Nadia A. Hassouna Microbiology and Immunology Department, Faculty of Pharmacy, Ain Shams University, PO: 11566, Cairo, Egypt.

Keywords:

Quorum quenching, lactonase, resistance, Pseudomonas aeruginosa, azithromycin

Abstract

Quorum quenching has lately become a focal point in research as a method of controlling infection and reducing virulence in pathogenic bacteria like P. aeruginosa. To investigate whether the ability of quorum quenching lactonase to reduce virulence was accompanied by any change in the resistance profile of P. aeruginosa clinical isolates, lactonase gene from a Bacillus isolate cloned and expressed in E.coli Bl21 (DE3) was used in this study. The biological activity of the produced Ahl-1 lactonase was validated using a standard signal and Chromobacterium violaceum CV026 as a biosensor. Results showed that the resistance profile of the tested P. aeruginosa isolates was not changed by Ahl-1 lactonase. Antibiogram analysis revealed that Ahl-1 quorum quenching activity had no influence on antibiotics prone to resistance mechanisms involving the expression of the chromosomally encoded AmpC, cephalosporinases nor OprD. Determination of the MIC of azithromycin alone and in combination with Ahl-1 lactonase displayed no change in the susceptibility of the tested isolates to azithromycin when Ahl-1 lactonase was added.