P2729 - Helicobacter pylori Resistance in Latin American Populations Using Next Generation Sequencing Technology With Formalin-Fixed Paraffin-Embedded Samples: Initial Results of a 10-Nation Study

Monday, October 23, 2023

10:30 AM – 4:15 PM PT

Location: Exhibit Hall

Presenting Author(s)

DM

Douglas Morgan, MD, MPH

University of Alabama at Birmingham
Birmingham, AL

Douglas Morgan, MD, MPH¹, Dalton A. Norwood, MD², Eleazar E.. Montalvan-Sanchez, MD³, Ricardo Dominguez, MD⁴, Arnoldo P. Riquelme, MD⁵, Gonzalo Latorre, MD⁶
¹University of Alabama at Birmingham, Birmingham, AL; ²UAB Minority Health and Health Equity Research Center, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, AL; ³Indiana University School of Medicine, Indianapolis, IN; ⁴Hospital de Occidente, Santa Rosa de Copan, Copan, Honduras; ⁵Pontificia Universidad Católica de Chile, Santiagio, Region Metropolitana, Chile; ⁶Pontificia Universidad Católica de Chile, Santiago, Region Metropolitana, Chile

Introduction: Next-Generation Sequencing (NGS) has the potential to improve Helicobacter pylori (Hp) antibiotic resistance testing, making it more accessible and efficient across various sample types. This enhances patient care by enabling individual resistance testing prior to treatment. In resource-limited settings, population sampling offers insight into local Hp ecology and resistance patterns. We conduct an initial study in Latin America using NGS for Hp resistance in varied populations in 10 countries, and report preliminary results from 2 countries.

Methods: Formalin-fixed paraffin-embedded samples were obtained from endoscopy biopsies. The NGS (PyloriARl; American Molecular Laboratories, Chicago, IL) identifies mutations or variances of the Hp DNA present in FFPE tissue. The platform permits simultaneous testing of 6 antibiotics based upon mutations for resistance: Clarithromycin (23S rRNA), Fluoroquinolones (gyrA), Metronidazole (rdxA), Amoxicillin (pbp1), tetracycline (16SrRMA), and Rifabutin (rpoB).

Results: The initial phase examined 164 recent FFPE samples from a diverse group of patients in Chile. Successful analysis was performed on 149 samples (90.9%). The analysis revealed varying resistance rates to specific antibiotics. 38.4% did not show resistance to any antibiotic. Resistance to one antibiotic was found in 31.7% of the samples. The resistance rates were: Clarithromycin (CLR) 40.3%, fluoroquinolones (Lfx) 33.6%, metronidazole (MTZ) 34.2%, Amoxicillin (AMOX) 2.7%, Rifabutin (Rfb) 0.7% and tetracycline (TET) 0.0%. The combination of CLR and Lfx showed resistance in 19.5%, CLR and MTZ 14.6%, and Lfx and MTZ 12.8%. Notably, in Chile, antibiotic use requires a prescription. The results were inadequate from a second nation wherein FFPE samples were greater than 12 months old.

Discussion: In the first phase of the 10-nation Latin America H. pylori antibiotic resistance study, high rates of resistance were observed for clarithromycin, fluoroquinolones, and metronidazole. Dual resistance with combinations of these antibiotics ranged 13-19.5%. Resistance to amoxicillin, tetracycline, and rifabutin were low. These results will help inform Ministry of Health Hp management guidelines in the region.

	Frequency (%)	Frequency 95% CI
Total Samples	164
Successful samples
No	15 (9.1%)	5.6-14.7
Yes	149 (90.9%)	85.3-94.3
Clarithromycin	60 (40.3%)	32.6-48.4
Tetracycline	0 (0.0%)
Fluoroquinolones	50 (33.6%)	26.4-41.6
Metronidazole	51 (34.2%)	27.0-42.26
Amoxicillin	4 (2.7%)	1,0-7.0
Rifabutin	1 (0.7%)	0.1-4.7
Resistant to (number of antibiotics)
None	63 (38.4%)	25.2-40.2
One	52 (31.7%)	27.6-43.0
Two	34 (20.7%)	16.7-30.3
Three	14 ( 8.5%)	5.6-15.3
Four	1 ( 0.6%)	0.1-4.7
Clarithromycin + Fluoroquinolones	32 (19.5%)	15.6-28.9
Clarithromycin + Metronidazole	24 (14.6%)	11.0-23.0
Fluroquinolones + Metronidazole	21 (12.8%)	9.3-20.7
Clarithromycin + Fluroquinolones + MTZ	14 ( 8.5%)	5.6-15.3

Disclosures:

Douglas Morgan: American Molecular Laboratory – Investigator initiated study, company donated analysis. CDx Diagnostics – Investigator initiated study, company donated analysis. Panbela Therapeutics – NCI-funded study, company donated study drug to the University. Thorne – NCI-funded study, company donated study drug to the University.

Dalton Norwood indicated no relevant financial relationships.

Eleazar Montalvan-Sanchez indicated no relevant financial relationships.

Ricardo Dominguez indicated no relevant financial relationships.

Arnoldo Riquelme indicated no relevant financial relationships.

Gonzalo Latorre indicated no relevant financial relationships.

Douglas Morgan, MD, MPH¹, Dalton A. Norwood, MD², Eleazar E.. Montalvan-Sanchez, MD³, Ricardo Dominguez, MD⁴, Arnoldo P. Riquelme, MD⁵, Gonzalo Latorre, MD⁶. P2729 - Helicobacter pylori Resistance in Latin American Populations Using Next Generation Sequencing Technology With Formalin-Fixed Paraffin-Embedded Samples: Initial Results of a 10-Nation Study, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.