Gastritis refers to inflammation or irritation of the lining of the stomach. It can be caused by various factors, including infections from bacteria, viruses, and parasites. While the bacteria Helicobacter pylori is the most common infectious cause of gastritis, there are several other types of infections that can also lead to stomach inflammation.
Bacterial Infections
In addition to H. pylori, other bacteria have been associated with gastritis as well. These include:
- Streptococci – Streptococcus species are linked to gastritis, especially in cases that occur after surgery.
- Staphylococci – Staphylococcus aureus is able to produce toxins that can damage the stomach lining.
- Mycobacteria – Mycobacterium tuberculosis is a rare cause of gastritis, usually in patients with tuberculosis.
- Treponema pallidum – The bacteria that causes syphilis can spread to the stomach in some cases, leading to inflammation.
The mechanisms by which these bacteria cause gastritis may include direct damage to stomach cells, production of inflammatory toxins, or invasion and replication within stomach tissue. Symptoms are similar to H. pylori gastritis and can include abdominal pain, nausea, vomiting, and bleeding.
Viral Infections
Viruses are not a frequent cause of gastritis, but certain viral infections have been associated with stomach inflammation, especially:
- Cytomegalovirus (CMV) – This common virus can affect the stomach in people with weakened immune systems, such as transplant patients or those with HIV/AIDS.
- Herpes simplex virus (HSV) – Both HSV-1 and HSV-2 can spread to the stomach lining in some cases.
- Varicella zoster virus (VZV) – The virus that causes chickenpox and shingles may rarely lead to gastritis.
It is thought that these viruses can directly infect and damage gastric epithelial cells. Symptoms of viral gastritis may include nausea, vomiting, pain, and bleeding. It is often seen in those who are immunocompromised.
Parasitic Infections
Certain parasitic organisms can also infect the stomach and cause inflammation. Parasites known to be associated with gastritis include:
- Giardia lamblia – This protozoan causes giardiasis, which may spread to the stomach.
- Strongyloides stercoralis – Gastritis can occur with infection by this roundworm.
- Ascaris lumbricoides – This intestinal roundworm can migrate and cause gastric inflammation.
- Anisakiasis – Infection by Anisakis worms from eating raw fish can lead to gastritis.
- Trypanosoma cruzi – The parasite that causes Chagas disease can affect the stomach.
In most cases, these parasites directly invade the gastric mucosa, where they produce toxins, damage cells, and trigger inflammation. Nausea, vomiting, and epigastric pain are common symptoms.
Fungal Infections
Fungal infections are uncommon causes of gastritis. However, the following fungi have been associated with stomach inflammation in some cases:
- Candida albicans – Overgrowth of this yeast in the stomach can lead to gastritis.
- Mucormycosis – Infection with Mucorales molds may spread to the stomach.
- Aspergillus – Aspergillus species can cause invasive gastric infections.
- Histoplasma – This fungus can affect the stomach in cases of disseminated histoplasmosis.
Symptoms are variable but may include fever, nausea, pain, and gastrointestinal bleeding. Fungal gastritis is most common in severely immunocompromised patients.
Other Causes of Infectious Gastritis
Some less common infections that may be associated with gastritis include:
- Mycobacterium avium complex (MAC)
- Pneumocystis jirovecii (seen in AIDS patients)
- Cryptosporidium
- Microsporidia
- Cyclospora cayetanensis
Gastritis can also sometimes occur following certain bacterial food poisoning infections, such as Salmonella, Campylobacter, and C. difficile colitis. Rarely, gastritis may be seen with zoonotic infections like brucellosis.
Diagnosis
Diagnosing infectious gastritis involves testing for the suspected organism as well as examining the stomach lining. Tests may include:
- Blood tests looking for antibodies to H. pylori or other bacteria/viruses
- Breath tests for active H. pylori infection
- Stool tests for parasites or bacterial toxins
- Endoscopy and biopsy to visualize stomach inflammation and test for organisms
- Culture of stomach biopsy specimens
- Molecular tests on biopsy samples like PCR
Often, standard triple therapy for H. pylori is tried first. If gastritis symptoms persist, testing for other organisms may be warranted based on risk factors and presentation.
Treatment
Treatment of infectious gastritis involves:
- Antibiotics to eradicate H. pylori or other bacterial infections
- Anti-parasitic medications for parasitic infections
- Antifungal medications for fungal infections
- Antiviral drugs in some cases of viral gastritis
- Medications to reduce stomach acid like PPIs or H2 blockers
- Avoiding triggers like alcohol, NSAIDs, spicy foods, and stress
Successful treatment of the underlying infection can resolve gastritis symptoms and allow healing of the stomach lining in many cases. Proton pump inhibitors and mucosal protective agents are often used alongside antimicrobial therapy.
Prevention
Preventing infectious gastritis relies on avoiding exposure to the causative organisms. Key prevention tips include:
- Practicing good hygiene and handwashing
- Avoiding contaminated water and food
- Cooking meat thoroughly and avoiding high-risk foods
- Treating underlying conditions that weaken immunity
- Getting H. pylori testing and treatment if needed
- Using protection and practising safe sex to prevent STIs like syphilis
- Avoiding excessive alcohol and NSAID use
Vaccinations are available for some pathogens that can cause gastritis, such as H. pylori, varicella, and hepatitis A virus. For people at high risk of severe infectious gastritis, antimicrobial prophylaxis may be warranted.
Conclusion
In summary, while H. pylori is the infection most commonly associated with gastritis, many other bacteria, viruses, fungi, and parasites can also infect the stomach lining and cause inflammation. Diagnosis involves testing for these organisms through blood work, breath tests, stool studies, endoscopy, and biopsy. Treatment requires targeting the underlying infection with appropriate antimicrobials and anti-inflammatory medications. Preventing infectious gastritis relies on good hygiene, avoiding contaminants, prompt treatment of infections, and lifestyle measures. With appropriate therapy, most cases of infectious gastritis can be cured.