H. pylori culture and antibiotic sensitivity testing
Gastric biopsies obtained during gastroscopy can be cultured in a laboratory to grow Helicobacter pylori and test its antibiotic susceptibility. This may help select eradication treatment; it answers a different question from an H. pylori breath test.
When may it be useful?
Susceptibility testing may be considered when infection persists after eradication treatment, particularly after repeated treatment failures. Decisions take account of previous regimens, adherence, allergies and local resistance information.
Culture or gastroscopy is not needed for every newly diagnosed infection. Bring previous prescriptions, antibiotic exposure details and test-of-cure results.
Sampling and preparation
Samples are usually taken from the stomach lining during gastroscopy. Culture needs dedicated collection and transport arrangements agreed with the laboratory in advance; a routine pathology sample is not automatically suitable.
Acid suppressants, antibiotics and bismuth can reduce sensitivity. A clinician plans any interruption; commonly PPIs need a break of about two weeks and antibiotics and bismuth about four weeks, but do not stop prescribed medicines yourself. Confirm fasting, sedation and gastroscopy risks separately.
Understanding limitations
If the organism grows, the laboratory can assess susceptibility or resistance to selected antibiotics. The panel and turnaround vary by laboratory. Results can guide treatment but do not guarantee eradication.
H. pylori is difficult to culture. Medicines, sampling, transport and handling can affect growth, so a negative culture does not rule out infection. Molecular resistance testing may be an alternative in selected settings but detects a different range of resistance markers.
Treatment and confirmation of cure
Treatment is chosen using the results alongside previous regimens and tolerability. Do not change antibiotics yourself. Culture and susceptibility testing do not replace confirmation that treatment has cleared the infection.
A urea breath test or appropriate stool antigen test is generally used at least four weeks after completing antibiotics, with acid suppression and other interfering medicines managed as instructed. Antibody blood tests are not suitable to confirm cure.