Differentiation of strains of Helicobacter pylori by numerical analysis of 1-D SDS-PAGE protein patterns: evidence for post-treatment recrudescence.

Twenty-three pre- and post-treatment isolates of Helicobacter pylori from the antral mucosa of eight patients with dyspepsia and gastritis were compared using 1-D SDS PAGE of proteins. The protein patterns were highly reproducible and were used as the basis for two numerical analyses. The first, based on the total protein patterns, showed that a number of the strains did not cluster with their respective patient set. This was thought to be due to differences in both mobility and intensity of proteins in the major band region. The second analysis, based on partial patterns, excluding the major band region (51-68 kDa), divided the clinical isolates into clearly defined groups corresponding to the patient sets. Although there was a degree of heterogeneity with respect to protein pattern between the pre- and post-treatment isolates of some patients, there was nonetheless clear evidence that each patient was harbouring strains of only a single type. These results suggested that patients were not being reinfected with a different strain but that there was recrudescence of the pre-treatment strain. Protein 'fingerprints' provided a precise and reproducible means of strain differentiation, and revealed that in each patient the same strain persisted after drug therapy even though there was marked patient-to-patient strain variation.