Helicobacter

Classificação

Características

Particularidades:

• Corantes:
  • Gram-negativo
  • Detetado com corante de prata
• Morfologia:
  • Bastonete móvel
  • Forma curva
  • Contém vários flagelos
• Crescimento e cultura:
  • Microaerofílico
  • Condições de crescimento complexas (requer meios de transporte especiais)
  • Oxidase Oxidase Neisseria positivo, catalase Catalase An oxidoreductase that catalyzes the conversion of hydrogen peroxide to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in acatalasia. Nocardia/Nocardiosis positivo
  • Produção de urease Urease An enzyme that catalyzes the conversion of urea and water to carbon dioxide and ammonia. Nocardia/Nocardiosis: cria um ambiente alcalino que permite a sobrevivência de bactérias na mucosa ácida

O género Helicobacter Helicobacter Helicobacter pylori is a gram-negative bacterium that causes gastric infection. It is the most well known and clinically significant species of Helicobacter. Transmission is believed to occur by ingestion of contaminated food or water; therefore, a higher prevalence of infection is seen in areas with poor sanitation. Helicobacter apresenta cerca de 35 espécies, sendo H. pylori H. pylori A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus campylobacter, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus Helicobacter. It has been officially transferred to Helicobacter gen. Helicobacter o mais MAIS Androgen Insensitivity Syndrome conhecido.

Patogénese

Transmissão

• Microorganismo onipresente
• Os seres humanos são o reservatório primário.
• Adquirido por:
  • Ingestão:
    • Transmissão oral-oral: bactérias regurgitadas com conteúdo gástrico que colonizam temporariamente a cavidade oral
    • Transmissão fecal-oral: alimentos e água contaminados (más condições sanitárias)
  • Contacto pessoa a pessoa: aglomerados de infeção observados nas famílias
• Prevalência da infeção:
  • Normalmente adquirida durante a infância
  • Uma das infeções bacterianas crónicas mais MAIS Androgen Insensitivity Syndrome comuns em todo o mundo
  • Cerca de dois terços da população mundial está infetada
  • Mais MAIS Androgen Insensitivity Syndrome elevada nos países em desenvolvimento

Características patogénicas de Helicobacter pylori Helicobacter pylori A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus campylobacter, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus Helicobacter. It has been officially transferred to Helicobacter gen. Helicobacter

• Microrganismo positivo para urease Urease An enzyme that catalyzes the conversion of urea and water to carbon dioxide and ammonia. Nocardia/Nocardiosis que produz amónia:
  • Neutraliza o ácido gástrico → hipocloridria → estimula a produção de gastrina → ácido gástrico aumentado → dano da mucosa
  • A neutralização inicial do ácido gástrico permite a colonização da mucosa.
• Os múltiplos flagelos permitem a penetração rápida da mucosa.
• Mucinase Mucinase An enzyme that catalyzes the random hydrolysis of 1, 4-linkages between N-acetyl-beta-D-glucosamine and D-glucuronate residues in hyaluronate. There has been use as antineoplastic agents to limit neoplasm metastasis. Helicobacter e citotoxinas:
  • Produzem dano tecidual local
  • Atuam como quimioatraentes e ativam a resposta inflamatória do hospedeiro
• A inflamação crónica leva a danos no ADN e à proliferação celular anormal → cancro
• Efeitos: gastrite, desenvolvimento de úlcera(s), carcinoma gástrico e linfomas MALT MALT Colon, Cecum, and Appendix: Anatomy gástricos

Doenças Associadas

Gastrite

• Aumento da produção de ácido gástrico ou dano da barreira da mucosa gástrica → irritação do revestimento sensível do estômago → gastrite
• A infeção por H. pylori H. pylori A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus campylobacter, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus Helicobacter. It has been officially transferred to Helicobacter gen. Helicobacter é uma das etiologias mais MAIS Androgen Insensitivity Syndrome comuns.
• Pode ser assintomática ou manifestar sintomas como dor abdominal associada a sensação de ardor, dispepsia, náuseas e vómitos
• Diagnóstico: teste respiratório com ureia, teste de antigénio nas fezes ou biópsia invasiva por endoscopia
• Tratamento da infeção por H. pylori H. pylori A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus campylobacter, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus Helicobacter. It has been officially transferred to Helicobacter gen. Helicobacter: uma combinação de antibióticos e inibidores da bomba de protões (IBP) ou um bloqueador ácido competitivo do potássio (P-CAB)
  • A seleção de um regime antibiótico deve ser orientada pelas taxas locais de resistência à claritromicina, metronidazol e levofloxacina.
  • Recomenda-se a realização de exames de acompanhamento 4 a 6 semanas após o tratamento para confirmar a erradicação.

Úlceras gástricas e duodenais

• Dois tipos mais MAIS Androgen Insensitivity Syndrome comuns de úlceras pépticas:
  • Úlcera gástrica:
    • Localizada no estômago
    • Classicamente associada à dor que agrava ao comer
  • Úlcera duodenal:
    • Localizada no duodeno
    • Habitualmente apresenta melhoria/alívio da dor ao comer, seguido de agravamento da dor após a refeição.
• As etiologias mais MAIS Androgen Insensitivity Syndrome comuns incluem infeção por H. pylori H. pylori A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus campylobacter, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus Helicobacter. It has been officially transferred to Helicobacter gen. Helicobacter e uso prolongado de AINEs.
• Tratamento:
  • Erradicação do H. pylori H. pylori A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus campylobacter, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus Helicobacter. It has been officially transferred to Helicobacter gen. Helicobacter (antibióticos mais MAIS Androgen Insensitivity Syndrome um IBPs ou um P-CAB)
  • Eliminação dos fatores de risco

Adenocarcinoma gástrico

• Neoplasia maligna do revestimento do estômago.
• Segundo cancro mais MAIS Androgen Insensitivity Syndrome comum do trato GI
• Infeção crónica por H. pylori H. pylori A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus campylobacter, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus Helicobacter. It has been officially transferred to Helicobacter gen. Helicobacter: associada a um risco aumentado de adenocarcinoma gástrico

Anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types por deficiência de ferro e deficiência de vitamina B ₁₂

Na infecção por H. pylori H. pylori A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus campylobacter, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus Helicobacter. It has been officially transferred to Helicobacter gen. Helicobacter :

• É observada ↓ da absorção de ferro no trato GI, pois a absorção de ferro requer um ambiente ácido.
• A gastrite crónica gera inflamação das células produtoras de ácido → perda da produção de ácido → absorção reduzida de ferro
• A inflamação contínua também leva à perda de células parietais a partir das quais o fator intrínseco é produzido.
• Sem fator intrínseco desenvolve-se, por conseguinte, défice de vitamina B ₁₂ .