A novel noninvasive genotyping method of Helicobacter pylori using stool specimens.
OBJECTIVE
The source(s) of the infection and the route(s) of transmission of Helicobacter pylori have not yet been clarified. This is to introduce a noninvasive protocol allowing molecular typing of H pylori using stool specimens.


METHODS
The genotyping method is based on 2 H pylori-specific biprobe real-time polymerase chain reaction assays using fragments of the glmM and the recA genes as target sequences. Discrimination between strains results from differences in the melting temperature during melting curve analysis. In case of identical melting temperatures in both assays, sequence analysis of the glmM amplicon was performed to confirm strain identity. The method was validated using gastric biopsy specimens and stool specimens of 97 unrelated individuals suffering from abdominal pain and stool specimens of members of 10 families in Austria (infected index child and family members) and 8 African households.


RESULTS
Of the 97 patients, 27 were infected as shown by culture, histology, and rapid urease test. The sensitivity of each of the assays was 100% in gastric biopsy specimens and 92.2% in stool specimens; the specificity was 100%. The discriminatory capacity of the method was 100%. Clonal identities were found in 9 of 10 (90%) European and 7 of 8 (87.5%) African households. In 2 African households, 2 different clonal lineages each were found.


CONCLUSIONS
The genotyping protocol introduced allows for both accurate detection and discrimination of H pylori strains in stool samples. Large-scale studies using this protocol may contribute to the clarification of the transmission pathways of infection with H pylori.
Division of Clinical Microbiology, Department of Hygiene and Medical Microbiology, Medical University of Vienna, Vienna, Austria.
Sonja
S
Puz
Albina
A
Innerhofer
Michael
M
Ramharter
Michael
M
Haefner
Alexander M
AM
Hirschl
Zsuzsanna
Z
Kovách
Manfred
M
Rotter
Athanasios
A
Makristathis
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001317:Austria; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000235:genetics*; D005243:Feces / Q000382:microbiology*; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology / Q000473:pathology; D005838:Genotype; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000382:microbiology / Q000635:transmission; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D019105:Random Amplified Polymorphic DNA Technique / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
D004269:DNA, Bacterial