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Helicobacter pylori Diagnosis

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Presenter:

Robin Patel, M.D.Consultant, Division of Clinical Microbiology Elizabeth P. and Robert E. Allen Professor of Individualized MedicineProfessor of Medicine and Microbiology

Department of Laboratory Medicine and Pathology at Mayo Clinic, Rochester, Minnesota

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DisclosuresDr. Patel reports grants from CD Diagnostics, Merck, Hutchison Biofilm Medical Solutions, Accelerate Diagnostics, ContraFect, TenNor Therapeutics Limited and Shionogi. Dr. Patel is a consultant to Curetis, Specific Technologies, Next Gen Diagnostics, PathoQuest, Selux Diagnostics, 1928 Diagnostics and Qvella; monies are paid to Mayo Clinic. In addition, Dr. Patel has a patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, and a patent on an anti-biofilm substance issued. Dr. Patel receives travel reimbursement from ASM and IDSA, an editor’s stipend from IDSA, and honoraria from the NBME, Up-to-Date and the Infectious Diseases Board Review Course.

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Helicobacter pylori: Bacteriology•Slender, curved Gram-negative bacillus•Urease-producer•Mucosa stomach•Growth

• Microaerophilic atmosphere, slow•World Health Organization

• Group 1 carcinogen (gastric carcinoma)Photo by Jamie Elvert

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Helicobacter pylori: Clinical Presentation•Asymptomatic•Peptic ulcer disease (gastric, duodenal)•Nonulcer dyspepsia •Gastric carcinoma•Gastric mucosa-associated lymphoid tissue lymphoma

• MALT lymphoma, MALToma, marginal zone B-cell lymphoma of MALT type

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Helicobacter pylori: Indications for Testing1

• Active peptic ulcer disease or history of peptic ulcer disease (unless H. pylori eradicated)

• Low-grade gastric mucosa–associated lymphoid tissue lymphoma or history of endoscopic resection of early gastric cancer

• Uninvestigated dyspepsia• Long-term NSAID or aspirin use• Unexplained iron-deficiency anemia

(after evaluation for other causes)• Immune thrombocytopenia in adults

1Crowe S. Helicobacter pylori infection. N Engl J Med 2019 March;380:1158-65

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Helicobacter pylori: Treatment2

• Typically treated with combinations of antibiotics along with a PPI• “…initial course of eradication therapy…generally offers the

greatest likelihood of treatment success. Thus, careful attention to the selection of the most appropriate first-line eradication therapy for an individual patient is essential.”

• “The main determinants of successful H. pylori eradication are the choice of regimen, the patient’s adherence to a multi-drug regimen with frequent side-effects, and the [susceptibility] of the H. pylori strain to the combination of antibiotics administered.”

2Chey W, Leontiadis G, Howden C, Moss S. ACG clinical guideline:Treatment of Helicobacter pylori infection. Am J Gastroenterol 2017 Feb; 112:212–238

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Susceptibility of 413 Helicobacter pylori Isolates, Mayo Clinic Laboratories3

MIC, minimum inhibitory concentration (in μg/ml); *EUCAST; **CLSI; S, susceptible; I, intermediate; R, resistant

Amoxicillin (n = 410) Ciprofloxacin (n = 409) Clarithromycin (n = 412) Metronidazole (n = 330) Tetracycline (n = 409)

MIC n % * MIC n % MIC % n *,** MIC n % * MIC n % *≤2 405 98.8 ≤1 190 46.5 ≤0.25 27.7 114 S ≤8 58 17.6 S ≤0.06 156 38.1 S4 1 0.2 R 2 8 2.0 0.5 1.9 8 I 16 24 7.3 R 1 246 60.1 S8 2 0.5 R >2 211 51.6 >0.5 70.4 290 R 32 66 20.0 R 2 3 0.7 R

>8 2 0.5 R 64 116 35.2 R >2 4 1.0 R128 63 19.1 R256 2 0.6 R

>256 1 0.3 R

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Genetic Mechanisms of Clarithromycin Resistance, 111 Helicobacter pylori Isolates, Mayo Clinic Laboratories3

• 23S ribosomal RNA gene sequencing → Assess clarithromycin resistance-associated mutations

• Overall concordance phenotypic & genotypic results - 106 (95%) isolates• Resistant isolates - 88 • Susceptible isolates – 23

• A2143G - 70 • A2143G – 2

• A2142G - 12 • Wild type - 21

• A2142C - 3

• Wild type - 3

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Helicobacter pylori: Diagnosis• Non-invasive tests

• Stool PCR• Predicts H. pylori clarithromycin susceptibility or resistance

• Stool antigen• Helicobacter pylori (urea) breath test

• C13 or C14-labeled urea ingested → C13 or C14-labeled CO2 detected

• Invasive tests - gastric biopsy• Rapid urease test • Stain of tissue• Culture

• Provides H. pylori isolate which is subjected to amoxicillin, levofloxacin, clarithromycin, metronidazole and tetracycline susceptibility testing

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Immunostaining H&E

Photos by Tsung-The Wu MD, PhD

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Photos by Jamie Elvert

Susceptibility control plate

0.25 μg/ml clarithromycin

Helicobacter pylori on HP agar

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Helicobacter pylori Diagnostic Algorithm

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Summary• Antimicrobial resistance in Helicobacter pylori is rising• Consideration should be given to assessing for H. pylori

antimicrobial susceptibility in patients testing positive for H. pylori

• Stool PCR with prediction of clarithromycin susceptibility provides an option in this regard, as does endoscopy with biopsy for culture and susceptibility testing

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References1. Crowe S. Helicobacter pylori infection. N Engl J Med

2019 March;380:1158-652. Chey W, Leontiadis G, Howden C, Moss S. ACG

clinical guideline: Treatment of Helicobacter pylori infection. Am J Gastroenterol 2017 Feb; 112:212–238

3. Chen D, Cunningham S, Nicolynn C, et al: Phenotypic and molecular antimicrobial susceptibility of Helicobacter pylori. Antimicrob Agents Chemother 2017 Apr;61:e02530-16

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