The mechanisms of virulence and antimicrobial resistance in Salmonella enterica serovar Typhi: A systematic review

Fowoyo P.T

doi:10.33472/afjbs.2.4.2020.13-26

Abstract

Salmonella enterica serovar Typhi is the etiologic agent of typhoid fever which is responsible for about 21,600 deaths annually, a large proportion of which is reported in developing countries. The organism is capable of evading the host defense mechanism to establish pathogenesis and this is enabled by the presence of specific virulence genes clustered in regions over the chromosome known as Salmonella Pathogenicity Island (SPI). Typhoid fever could be fatal therefore it requires effective antibiotic therapy. Strains which are antibiotic resistant could lead to increased mortality rates due to failure of routinely used antibiotics. This review gives an insight into the molecular mechanisms of virulence and antibiotic resistance so as to enhance more effective disease management and control.

Highlights

S. enterica serovar Typhi is the causative agent of typhoid fever which is a systemic, life threatening disease of humans (Galan, 2016)
The ability of S. enterica serovar Typhi to invade the host cells and disseminate in the body is closely related to its virulence genes
There are about 13 Salmonella Pathogenicity Island (SPI) in S. enterica serovar Typhi it has been observed that SPI-1 and SPI-2 contributes significantly to the virulence of S. enterica serovar Typhi because they carry the genes for invading the host intestinal epithelium and to survive in the host intestine and macrophages

Summary

Introduction

Salmonella is a gram-negative, non-capsulated, non-spore forming rod that is motile with peritrichous flagella and possess outer coat antigens (Shahane et al, 2007). S. enterica serovar Typhi is the causative agent of typhoid fever which is a systemic, life threatening disease of humans (Galan, 2016). S. enterica serovar Typhi is a gram-negative, rod-shaped, flagellated bacterium whose only reservoir is the human body (Crump et al, 2015) It is the etiologic agent of an enteric fever called typhoid fever and considered a public health problem in the world (Fallah et al, 2016). They are intracellular pathogens with the ability of systemic spread and can populate the intestinal lumen, causing diseases such as typhoid fever, blood infections and food borne gastroenteritis, depending on the host-pathogen-pairing. Together with S. enterica serovar Typhi, these pathogens are commonly referred to as typhoidal Salmonella serotypes

Pathogenesis elucidated by typhoidal toxin

Salmonella Pathogenicity Island (SPI)

Flagella and fimbriae

Vi antigen

Findings

Conclusion