Vector potential of cockroaches for Helicobacter pylori infection

OBJECTIVES: The routes of human infection with Helicobacter pylori remain unclear. In the present study, we examined cockroaches as possible vectors for transmission of H. pylori. METHODS: We used a common species of cockroach (Periplaneta fuliginosa). After a 3-day fast, cockroaches were placed on agar plates containing freshly grown H. pylori (Sydney strain) (challenge group) or on sterile agar plates without H. pylori (control group). After 24 h of challenge, cockroaches were moved to disinfected containers, and sterile food and water were provided. The external surfaces (legs and body) and excreta of the cockroaches were sampled for culture, rapid urease test, and polymerase chain reaction (PCR). RESULTS: H. pylori were culturable from the excreta of the challenge group for 24 h postchallenge. Positive rapid urease test results were obtained up to day 3, and PCR analysis was positive for H. pylori DNA up to day 7 from the excreta. In contrast, H. pylori were not culturable from the external surfaces of the cockroaches. The rapid urease test was positive for only 8 h, and PCR analysis was positive for H. pylori DNA for 1 day from the external surface. CONCLUSIONS: Cockroaches usually live in unsanitary environments and may contaminate foods and food containment areas such as pantries. Transmission of H. pylori infection could be achieved via inadvertent ingestion of foods contaminated with cockroach excreta containing viable H. pylori.