# Bioactivity of green-synthesized zinc oxide nanoparticles using Fusarium oxysporum extract on the expression of extended-spectrum beta-lactamase and biofilm-associated genes in the pathogen Klebsiella pneumoniae

## TL;DR

This study shows that green-synthesized zinc oxide nanoparticles can reduce antibiotic resistance and biofilm formation in Klebsiella pneumoniae.

## Contribution

The novel contribution is demonstrating that biosynthesized zinc oxide nanoparticles downregulate ESBL and biofilm-related genes in MDR K. pneumoniae.

## Key findings

- Zinc oxide nanoparticles had a minimum inhibitory concentration of 26 μg/ml against K. pneumoniae.
- Nanoparticles downregulated ESBL genes (blaTEM, blaCTX-M, blaSHV) and biofilm genes (mrkA, luxS) below a ratio of 1.0.
- Biosynthesized zinc oxide nanoparticles show potential as an alternative or supplement to antibiotics for MDR bacteria.

## Abstract

Multidrug-resistant Klebsiella pneumoniae poses a serious clinical threat because of its ability to form biofilms and generate extended-spectrum beta-lactamase enzymes (ESBLs). This research investigated the influence of biosynthesized zinc oxide nanoparticles made from Fusarium oxysporum alcohol extract (FOE) on ESBL genes (blaTEM, blaCTX-M, blaSHV) and the biofilm-associated genes mrkA and luxS. The presence of the 16S rRNA, ESBL and biofilm genes was confirmed through subsequent polymerase chain reaction of the isolates. The FOE and zinc oxide nanoparticles both demonstrated significant antibacterial activity, with zinc oxide nanoparticles exhibiting greater inhibition with a minimum inhibitory concentration (MIC) of 26 μg/ml. Compared with untreated and FOE-treated isolates, those treated with sub-MIC concentrations of zinc oxide nanoparticles expressed significantly fewer ESBL and biofilm-related genes. The expression levels of the genes blaTEM, blaCTX-M, blaSHV, mrkA and luxS were downregulated below a ratio of 1.0 in each of the bacterial isolates. The biosynthesized zinc oxide nanoparticles demonstrated strong antibacterial and antibiofilm effects through the downregulation of bacterial antibiotic resistance and virulence genes in K. pneumoniae. The findings of this study demonstrate the ability of biosynthesized zinc oxide nanoparticles to function as a green and apotential alternative or support the role of antibiotcs for the treatment of multidrug-resistant (MDR) bacteria.