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Antagonistic Activities of Cell-Free Supernatants of Lactobacilli Against Extended-Spectrum β-Lactamase Producing Klebsiella pneumoniae and Pseudomonas aeruginosa

Authors El-Mokhtar MA, Hassanein KM, Ahmed AS, Gad GFM, Amin MM, Hassanein OFE

Received 22 October 2019

Accepted for publication 23 January 2020

Published 17 February 2020 Volume 2020:13 Pages 543—552


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Professor Suresh Antony

Mohamed A El-Mokhtar, 1 Khaled M Hassanein, 1 Ahmed S Ahmed, 1 Gamal FM Gad, 2 Mohamed M Amin, 3 Osama FE Hassanein 4

1Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt; 2Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia, Egypt; 3Department of Microbiology and Immunology, Faculty of Medicine, Aswan University, Aswan, Egypt; 4Drug Research Center, Assiut University, Assiut, Egypt

Correspondence: Mohamed A El-Mokhtar
Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut 71515, Egypt
Tel +20 122 111 53 13

Aim: This study aimed to describe the inhibitory activity of cell-free supernatants (CFS) of lactobacilli against extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae (K pneumoniae) and Pseudomonas aeruginosa (P aeruginosa).
Material and Methods: Pathogenic clinical strains of K pneumoniae and P aeruginosa were isolated from urine samples and selected for investigation. Anti-bacterial activities of the CFS of lactobacilli were assessed by agar well diffusion, MTT assay, as well as time-kill tests. In addition, the antibiofilm characteristics were analyzed by the microplate method against fresh and 24 h-old biofilms. The ability of CFS to interfere with bacterial invasion was analyzed by flow cytometry.
Results: Although all tested strains were ESBL producers and showed a multidrug-resistant phenotype, the CFS displayed a high anti-ESBL activity with inhibition zone diameters greater than 13 mm in the agar well diffusion assays against both pathogens. The growth kinetics of K pneumoniae and P aeruginosa were dramatically decreased in the presence of the CFS. The CFS not only inhibited the biofilm formation by these pathogens but also was able to remove the 24-h formed biofilms. The invasion abilities of FITC-labelled K pneumoniae decreased from 30.3%± 7 to 15.4%± 5 and invasion of FITC-labelled P aeruginosa was reduced from 36.9%± 7 to 25.2%± 5.
Conclusion: CFS of lactobacilli exhibit anti-ESBL activities, which suggests its potential application for controlling or preventing colonization of infections caused by ESBL-producing bacteria.

Keywords: lactobacilli, antibiofilm, ESBL, K pneumoniae, P aeruginosa

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