Can you have bacterial gastritis?

Bacterial Gastritis: Causes and Clinical Implications

Yes, bacterial gastritis exists, with Helicobacter pylori being the most significant and well-established bacterial cause of gastritis, responsible for 71-95% of all gastric cancer cases. 1

H. pylori Gastritis

• H. pylori is the primary bacterial cause of gastritis, recognized as the most important factor in the pathogenesis of chronic gastritis 2, 1
• The infection causes persistent active gastritis characterized by neutrophil infiltration in the necks of gastric glands, just deep to the infected foveolae 3
• H. pylori gastritis is associated with epithelial damage, reduced mucus secretion, and lymphoid infiltration that can persist for decades without treatment 3
• The pattern of gastritis affects acid secretion - antral-predominant gastritis leads to increased acid production, while body-predominant gastritis causes decreased acid production 1
• Corpus-predominant H. pylori gastritis substantially increases the risk for gastric cancer development 1

Other Bacterial Causes of Gastritis

• While H. pylori is the predominant bacterial cause, other bacteria can occasionally cause gastritis 4
• Enterococcus species have been documented to cause gastritis, particularly in immunocompromised patients such as those with diabetes 5
• In patients with achlorhydria (such as those with pernicious anemia or atrophic gastritis), overgrowth of non-H. pylori urease-producing organisms can occur 2
• Gastric acid suppression through proton pump inhibitors increases gastric counts of bacteria normally present in the gastrointestinal tract 6
• Treatment with proton pump inhibitors may slightly increase the risk of gastrointestinal infections from bacteria such as Salmonella, Campylobacter, and Clostridium difficile 6

Progression and Complications of Bacterial Gastritis

• H. pylori gastritis can progress through a cascade: chronic active gastritis → atrophic gastritis → intestinal metaplasia → gastric cancer 2
• The lifetime risk of peptic ulcer disease is approximately 17% in those infected with H. pylori 2
• Gastric cancer is the third most common cause of cancer death worldwide, with H. pylori infection increasing the risk by approximately 2.5-fold 1, 7
• The risk of progression from atrophic gastritis to gastric adenocarcinoma ranges from 0.1% to 0.3% per year 1
• Eradication of H. pylori infection halts the progression of gastritis, alters the natural history of the disease, and reduces the overall risk of gastric cancer 2

Diagnosis of Bacterial Gastritis

• H. pylori infection can be diagnosed through non-invasive tests such as urea breath test (UBT) and monoclonal stool antigen tests 1
• Endoscopy with biopsy allows for histological examination, which can identify both H. pylori and the pattern/severity of gastritis 2
• False positive UBT results can occur in patients with achlorhydria due to overgrowth of non-H. pylori urease-producing organisms 2
• When false positive tests are suspected, confirmation with stool antigen test or endoscopy is recommended before administering another course of therapy 2
• In histologic specimens, immunohistochemical staining for H. pylori should be utilized when the organism is difficult to find but H. pylori-associated inflammation is present 2

Treatment Implications

• Eradication of H. pylori infection is recommended whenever it is diagnosed, as it is now recognized as an infectious disease with significant risk to the host 2
• Triple therapy with a proton pump inhibitor, clarithromycin, and amoxicillin is a common first-line treatment regimen 6, 8
• Patients with clarithromycin-resistant H. pylori should not be treated with regimens that include clarithromycin as the sole antimicrobial agent 6
• H. pylori eradication leads to resolution of active gastritis changes within days, though lymphoid infiltration may take months or years to fully resolve 3
• Eradication of H. pylori infection before the development of preneoplastic conditions is most effective in reducing gastric cancer risk 2

Clinical Considerations

• Despite causing chronic inflammation, H. pylori gastritis is often asymptomatic 3
• The relationship between H. pylori gastritis and non-ulcer dyspepsia symptoms remains controversial 3
• Patients should be informed about their infection status, associated pathology, relationship to symptoms, and treatment options 3
• Specific high-risk populations (Native Americans, blacks, Hispanics, and immigrants from high-risk countries) warrant increased awareness and focused testing for H. pylori 2
• In countries with high gastric cancer risk, population-wide H. pylori eradication programs have shown effectiveness in reducing peptic ulcer, premalignant lesions, and gastric cancer incidence 2