Aqueous extract of Hibiscus sabdariffa inhibits pedestal induction by enteropathogenic E. coli and promotes bacterial filamentation in vitro.

Reda Mohamed-Salem,Beatriz Conde-Valentín,Narcisa Martinez-Quiles,Elvira Nieto-Pelegrín,Angel Rumbero,Carmina Rodríguez Fernández,Amitava Mukherjee

doi:10.1371/journal.pone.0213580

Reda Mohamed-Salem, Beatriz Conde-Valentín + Show 5 more

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https://doi.org/10.1371/journal.pone.0213580

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Abstract

Diarrheic diseases account for the annual death of approximately 1.9 million children under the age of 5 years, and it is a major cause of work absenteeism in developed countries. As diarrheagenic bacteria, enteropathogenic Escherichia coli (EPEC) attach to cells in the small intestine, causing local disappearance of microvilli and inducing the formation of actin-rich pedestals that disrupt the intestinal barrier and help EPEC adhere to and infect intestinal cells. Antibiotics and other bioactive compounds can often be found by analyzing traditional medicines. Here a crude aqueous extract of Hibiscus sabdariffa, which typically grows in subtropical and tropical areas and is a popular medicinal tisane in many countries, was analyzed for antibacterial activity against EPEC. In standard microdilution assays, the extract showed a minimum inhibitory concentration of 6.5 mg/ml against EPEC growth. Time-kill kinetics assays demonstrated significant 24 h bactericidal activity at 25 mg/ml. The extract is able to impede pedestal induction. Not only did the extract inhibit preformed pedestals but it prevented pedestal induction as well. Remarkably, it also promoted the formation of EPEC filaments, as observed with other antibiotics. Our results in vitro support the potential of Hibiscus sabdariffa as an antimicrobial agent against EPEC.

Highlights

Pathogenic strains of Escherichia coli, which are broadly categorized as either diarrheagenic or extraintestinal [1,2,3], have acquired virulence factors that provide them with the ability to cause a broad range of diseases in humans
The minimum bactericidal concentration (MBC) of Hibiscus sabdariffa L. (HS) extract was estimated to be 25 mg/ml against enteropathogenic E. coli (EPEC), since growth was occasionally detected at 20 mg/ ml (Fig 1)
We studied the effect of Hibiscus sabdariffa aqueous extract on EPEC

Summary

Introduction

Pathogenic strains of Escherichia coli, which are broadly categorized as either diarrheagenic or extraintestinal [1,2,3], have acquired virulence factors that provide them with the ability to cause a broad range of diseases in humans. Among diarrheagenic E. coli, enteropathogenic E. coli (EPEC) is an important cause of food- and water-borne diarrhea illness worldwide, especially in developing countries [4]. EPEC infection results in diarrhea, vomiting, fever and even death, contributing to 10–40% of deaths due to diarrhea among children under the age of five.

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