Patient-to-patient transmission of Campylobacter pylori infection by fiberoptic gastroduodenoscopy and biopsy.

Three instances of subclinical reinfection with Campylobacter pylori were observed in two successfully treated patients during follow-up of C. pylori gastritis. The reinfections occurred 1 month and 21 months (patient 1) and 32 months (patient 2) after the completion of antibacterial treatment. Sequential measurement by ELISA of serum IgG antibody levels to the microorganism showed a significant increase in two of the three instances of reinfection. Patient-to-patient transmission was proved by restriction enzyme analysis of bacterial DNA. Between patients the endoscope had been mechanically cleaned using a detergent and treated with 70% ethanol. The risk of gastroscopic cross-infection with C. pylori was estimated by retrospective analysis of the data of 281 negative examinations (107 in 47 initially negative patients and 174 in 37 cured patients). The frequency in uninfected patients of documented endoscopic transmission of C. pylori infection was 1.1% in this study, corresponding with three iatrogenic acquisitions of manifest infection for every 1000 gastroduodenoscopies in our clinic.