Long-Term Persistence of Resistant Enterococcus Species after Antibiotics To Eradicate Helicobacter pylori

16 September 2003 | Volume 139 Issue 6 | Pages 483-487

Background: Antibiotic treatment selects for resistance not only in the pathogen to which it is directed but also in the indigenous microflora.

Objective: To determine whether a widely used regimen (clarithromycin, metronidazole, and omeprazole) for Helicobacter pylori eradication affects resistance development in enterococci.

Design: Cohort study.

Setting: Endoscopy units at 3 community hospitals in Sweden.

Patients: 5 consecutive dyspeptic patients who were colonized with H. pylori, had endoscopy-confirmed duodenal ulcer, and received antibiotic treatment, and 5 consecutive controls with dyspepsia but no ulcer who did not receive treatment.

Measurements: Fecal samples were obtained from patients and controls before, immediately after, 1 year after, and 3 years after treatment. From each patient and sample, enterococci were isolated and analyzed for DNA fingerprint, clarithromycin susceptibility, and presence of the erm(B) gene.

Results: In treated patients, all enterococci isolated immediately after treatment showed high-level clarithromycin resistance due to erm(B). In 3 patients, resistant enterococci persisted for 1 to 3 years after treatment. No resistance developed among controls.

Conclusion: A common H. pylori treatment selects for highly resistant enterococci that can persist for at least 3 years without further selection.

Editors' Notes Context Antibiotics are selective killers. Regardless of the indication, they may leave behind resistant bacteria. Contribution In this study, fecal enterococci isolated from 5 dyspeptic patients treated with clarithromycin for ulcers associated with Helicobacter pylori infection were compared with enterococci from 5 dyspeptic patients without ulcers who did not receive antibiotics. All enterococci isolated immediately after treatment were highly resistant to clarithromycin; enterococci in untreated patients were clarithromycin sensitive. In 3 treated patients, resistant organisms persisted for 1 to 3 years. Implications Short-term clarithromycin treatment of H. pylori infection leaves behind indigenous bacteria resistant to that antibiotic. –The Editors

 

Author and Article Information

From University Hospital Uppsala, Uppsala, and The Swedish Institute for Infectious Disease Control, Solna, Sweden; and New York University School of Medicine, New York, New York.

Acknowledgments: The authors thank Lena Zimmergren for coordinating the collection of samples and Lena Eriksson and Kristina Schönmeyr for excellent technical assistance.

Grant Support: By the AFA Health Research Foundation, Stockholm, Sweden, and by the National Institutes of Health (RO1GM63270).

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Lars Engstrand, MD, Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden; e-mail, lars.engstrand{at}smi.ki.se.

Current Author Addresses: Ms. Sjölund: Department of Medical Sciences, Clinical Bacteriology, University Hospital Uppsala, Box 552, SE-751 22 Uppsala, Sweden.

Ms. Wreiber and Drs. Andersson and Engstrand: Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden.

Dr. Blaser: Departments of Medicine and Microbiology, New York University School of Medicine, New York, NY 10016.

Author Contributions: Conception and design: M. Sjölund, L. Engstrand.

Analysis and interpretation of the data: M. Sjölund, D.I. Andersson, M.J. Blaser, L. Engstrand.

Drafting of the article: M. Sjölund, D.I. Andersson, M.J. Blaser, L. Engstrand.

Critical revision of the article for important intellectual content: M. Sjölund, D.I. Andersson, M.J. Blaser, L. Engstrand.

Final approval of the article: M. Sjölund, K. Wreiber, D.I. Andersson, M.J. Blaser, L. Engstrand.

Provision of study materials or patients: K. Wreiber.

Obtaining of funding: L. Engstrand.

Administrative, technical, or logistic support: K. Wreiber, L. Engstrand.

Collection and assembly of data: K. Wreiber, L. Engstrand.