Descrição
Triple therapy is the gold standard treatment for Helicobacter pylori eradication from the human
stomach, but increased resistance to clarithromycin became the main factor of treatment failure. Until now,
fastidious culturing methods are generally the method of choice to assess resistance status. In this study, a new
genotypic method to detect clarithromycin resistance in clinical samples, based on fluorescent in situ hybridization
(FISH) using a set of peptide nucleic acid probes (PNA), is proposed.
Results: The set of probes targeting the point mutations responsible for clarithromycin resistance was applied to
H. pylori suspensions and showed 100% sensitivity and specificity (95% CI, 79.9-100 and 95% CI, 71.6-100
respectively). This method can also be amenable for application to gastric biopsy samples, as resistance to
clarithromycin was also detected when histological slides were tested.
Conclusions: The optimized PNA-FISH based diagnostic method to detect H. pylori clarithromycin resistance
shown to be a very sensitive and specific method for the detection of clarithromycin resistance in the H. pylori
smears and also proved to be a reliable method for the diagnosis of this pathogen in clinical samples and an
alternative to existing plating methods.
; Cerqueira, L. 
