Helicobacter pylori (H. pylori) è un batterio gram-negativo e microaerofilo che si trova nello stomaco. È noto per il suo ruolo nel causare ulcere gastriche e gastrite cronica, condizioni che sono precursori del cancro allo stomaco. È adattato in modo unico a sopravvivere nel duro ambiente acido dello stomaco.

Il nome definisce la forma e il luogo dove si trova questo batterio:

• Helicobacter si riferisce alla forma elicoidale del batterio. Questa forma a spirale lo aiuta a penetrare nella mucosa dello stomaco e ad attaccarsi alle cellule epiteliali sottostanti.
• Pylori si riferisce al piloro, l'area dello stomaco in cui spesso si trova questo batterio.

È dotato di flagelli, appendici simili a fruste che gli consentono di muoversi.

Produce un enzima chiamato ureasi, che neutralizza gli acidi dello stomaco convertendo l'urea in ammoniaca e anidride carbonica, creando un ambiente più ospitale per il batterio che ha un modo unico di eludere la risposta immunitaria dell'organismo, consentendogli di persistere nello stomaco per lunghi periodi, spesso per tutta la vita dell'ospite se non viene trattato.

Si acquisisce tipicamente durante l'infanzia e può essere trasmesso da persona a persona attraverso la saliva, la contaminazione fecale o le scarse pratiche igieniche.

La cura di solito prevede una combinazione di antibiotici e inibitori della pompa protonica per ridurre i succhi gastrici e consentire agli antibiotici di agire più efficacemente.

Studi

Matsuo Y, Kido Y, Yamaoka Y. Helicobacter pylori Outer Membrane Protein-Related Pathogenesis. Toxins (Basel). 2017 Mar 11;9(3):101. doi: 10.3390/toxins9030101. 

Abstract. Helicobacter pylori colonizes the human stomach and induces inflammation, and in some cases persistent infection can result in gastric cancer. Attachment to the gastric mucosa is the first step in establishing bacterial colonization, and outer membrane proteins (OMPs) play a pivotal role in binding to human cells. Some OMP interaction molecules are known in H. pylori, and their associated host cell responses have been gradually clarified. Many studies have demonstrated that OMPs are essential to CagA translocation into gastric cells via the Type IV secretion system of H. pylori. This review summarizes the mechanisms through which H. pylori utilizes OMPs to colonize the human stomach and how OMPs cooperate with the Type IV secretion system.

Gu H. Role of Flagella in the Pathogenesis of Helicobacter pylori. Curr Microbiol. 2017 Jul;74(7):863-869. doi: 10.1007/s00284-017-1256-4. 

Abstract. This review aimed to investigate the role of Helicobacter pylori flagella on the pathogenicity of this bacterium in humans. Helicobacter pylori is a flagellated pathogen that colonizes the human gastroduodenal mucosa and produces inflammation, and is responsible for gastrointestinal disease. Its pathogenesis is attributed to colonization and virulence factors. The primary function of H. pylori flagella is to provide motility. We believe that H. pylori flagella play an important role in the colonization of the gastrointestinal mucosa. Therefore, we reviewed previous studies on flagellar morphology and motility in order to explore the relationship between H. pylori flagella and pathogenicity. Further investigation is required to confirm the association between flagella and pathogenicity in H. pylori.

Sabbagh P, Javanian M, Koppolu V, Vasigala VR, Ebrahimpour S. Helicobacter pylori infection in children: an overview of diagnostic methods. Eur J Clin Microbiol Infect Dis. 2019 Jun;38(6):1035-1045. doi: 10.1007/s10096-019-03502-5. 

Abstract. Children differ from adults regarding Helicobacter pylori (H. pylori) infection in many terms. H. pylori infection represents a key factor in the pathogenesis of duodenal ulcer and chronic gastritis in children. H. pylori infection causes some extraintestinal diseases as well as gastrointestinal diseases. Although, among these illnesses in children, symptoms like recurrent abdominal pain are not specific. Moreover, the role of the pathogen in the growth faltering, iron deficiency anemia, and asthma still remains controversial. A reliable method to detect H. pylori infection is a crucial issue, sand is still a matter of active debate. The tests applied for H. pylori diagnosis are grouped as either invasive or non-invasive methods. Invasive methods consist of endoscopic evaluation, the rapid urease test (RUT), histology, and bacterial culture. Non-invasive tests include the urea breath test (UBT), stool antigen test (SAT), serology, and molecular diagnostic approaches. Use of endoscopy is a pre-requisite for all invasive methods and poses difficulties in children as it is a difficult procedure and requires patient's cooperation. For this reason, the non-invasive tests have been commonly used in children, although their accuracy is not very reliable in some cases. Invasive tests may be opted to confirm the diagnosis as and when needed. This review presents the diagnostic tests used to detect H. pylori infection in children.