Antibiotic treatment selects for resistance in both the pathogen and the indigenous microflora.
In this study, physicians from Sweden and the United States evaluated whether a widely used regimen for Helicobacter pylori eradication influence resistance development in enterococci.
The research team evaluated 5 consecutive dyspeptic patients with H. pylori infection and duodenal ulcers. Patients had received antibiotic treatment.
The patients were compared with 5 consecutive controls, who had dyspepsia but no ulcers. These controls did not receive treatment.
The physicians obtained fecal samples from study subjects before, immediately after, 1 year after, and 3 years after treatment.
They isolated enterococci from each sample and patient, and analyzed these for DNA fingerprint, clarithromycin susceptibility, and presence of the erm(B) gene.
The team determined that enterococci isolated immediately after treatment showed high-level clarithromycin resistance due to erm(B).
In addition, they found that resistant enterococci persisted for 1 to 3 years in 3 of the treated patients.
|Resistant enterococci persisted for 1 to 3 years.|
|Annals of Internal Medicine|
The physicians did not identify any resistance in the controls.
Dr Maria Sjölund's team concluded, "A common H. pylori treatment selects for highly resistant enterococci that can persist for at least 3 years without further selection".