DENSITY OF HELICOBACTER-PYLORI INFECTION IN-VIVO AS ASSESSED BY QUANTITATIVE CULTURE AND HISTOLOGY

Helicobacter pylori density was assessed by quantitative culture and h istologic examination of gastric biopsy specimens from 29 H. pylori-in fected dyspeptic patients. Density was correlated with cagA and vacA g enotypes (assessed by polymerase chain reaction and colony hybridizati on), gastric inflammation and epithelial injury (assessed histological ly), and peptic ulceration. Quantitative culture was more reproducible than histology, and antral density was more reproducible than corpus density. Mean antral density of cagA(+)/vacA s1 strains was 4-fold hig her than that of cagA(-)/vacA s2 strains (1.9 x 10(6) vs. 4.5 x 10(5) cfu/g, P =.02). Antral density was associated with mucosal neutrophili c and lymphocytic infiltration (P <.01) and with epithelial injury (P <.05). Mean antral bacterial density was 5-fold higher in duodenal ulc er patients than in others (P =.005). In conclusion, H. pylori density in vivo is easily quantified and is associated with bacterial virulen ce determinants, gastric inflammation, and duodenal ulceration, sugges ting a central role in pathogenesis.