Molecular Diagnostics Of Helicobacter Pylori

Molecular Diagnostics

Report

Helicobacter pylori infection and diagnostics

Lina Staniute – s162982

DTU – Denmark Technical University

2017

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Contents

1. Abstract………………………………………………………………………..3

2. Introduction……………………………………………………………………4

3. Diagnostic methods and diagnostic problem…………………………………..4

4. Genome of Helicobacter pylori and considerable targets……………………..5

5. Selection of primers and probes for PCR design………………………………6

6. Workflow of PCR with selected strains, primers and probes………………….8

7. Possibilities of using PCR for strain differentiation and application for point-of-

care diagnostics…………………………………………………………………8

8. References………………………………………………………………..……10

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Abstract

Nowadays it is known that we have bacteria everywhere even in our stomach. One of them is

Helicobacter pylori. This pathogen affects around a half of world population and causes

serious and unpleasant problems like gastric inflammation and ulceration (Kusters et al.,

2006). Also this pathogen is considered to be cancerogenic and if infection is left untreated it

can lead to stomach cancer and terminate in death (Stewart & Wild, 2014). Therefore, early

detection of this in infection is needed. Even though, there are effective methods to detect

H.pylori usually infection is already advanced. Treatment normally includes antibiotics,

however growing resistance to them remain a high issue and complicates treatment (Garza-

Gonzalez et al., 2014). Moreover, bacteria itself is very adaptive, flexible and acquire

mutations relatively easy contributing not only to difficult treatment but also increasing the

resistance to antibiotics (Kusters et al., 2006). As a result, novel diagnostic techniques are

proposed that could allow different strains to be differentiated and suitable treatment would

be applied. Polymerase chain reaction is a molecular diagnostic method which permit to do

so in collaboration with other diagnostic tools, however there is still a need to make advances

in this method to make it a gold standard (Kalali et al., 2015).

Introduction

Helicobacter pylori is a gram-negative gastric pathogen. Around 50% of people worldwide

are affected by this microorganism, especially those people living in developing countries.

(Garza-Gonzalez et al., 2014) Even though around 20% of infected people develop

pathologies such as gastritis or peptic ulcers, carriers are under a great risk as well. According

to World Health Organization (WHO) this bacteria is a cancerogenic and can act secretly

causing stomach cancer. Stomach cancer by WHO is fourth leading in cancer diseases

terminating with death (Stewart & Wild, 2014). High rate of this is mainly caused by the fact

that people are not aware that they are carriers, since not all of the people feel discomfort or

any signs and symptoms of this microorganism. Some of the people might even live all their

lives not knowing that they are affected (Kusters et al., 2006). However, when people start

noticing that something is wrong usually it is very hard to treat it or it is already too late to

help them. Taking into account that stomach is one of the organs which is vital for our

survival it is necessary to pay more attention to this problem.

Diagnostic methods and diagnostic problem

There are various diagnostic methods created to detect this Helicobacter pylori. All of them