Interaction of Vibrio spp. with the Inner Surface of the Digestive Tract of Penaeus monodon.
Several species of Vibrio are the causative agent of gastroenteritis in humans. In aquaculture, Vibrio harveyi (Vh) and V. parahaemolyticus (Vp) have long been considered as shrimp pathogens in freshwater, brackish and marine environments. Here we show by using scanning electron microscopy (SEM) that Penaeus monodon orally inoculated with each of these two pathogens via an Artemia diet had numerous bacteria attached randomly across the stomach surface, in single and in large biofilm-like clusters 6 h post-infection. A subsequent marked proliferation in the number of V. harveyi within the biofilm-like formations resulted in the development of infections in the stomach, the upper and middle midgut, but neither in the posterior midgut nor the hindgut. SEM also revealed the induced production of peritrichous pili-like structures by the Vp attaching to the stomach lining, whilst only a single polar fibre was seen forming an apparent physical bridge between Vh and the host's epithelium. In contrast to these observations, no such adherences or linkages were seen when trials were conducted with non-pathogenic Vibrio spp. or with Micrococcus luteus, with no obvious resultant changes to the host's gut surface. In naive shrimp, the hindgut was found to be a favorable site for bacteria notably curved, short-rod shaped bacteria which probably belong to Vibrio spp. Data from the current study suggests that pathogens of P. monodon must be able to colonize the digestive tract, particularly the stomach, where chitin is present, and then they use an array of virulent factors and enzymes to infect their host resulting in disease. Oral infection is a better way of mimicking natural routes of infection; investigating the host-bacteria interactions occurring in the digestive tract may lead to new strategies for the prevention or control of bacterial infections in penaeids.
Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Wipasiri
W
Soonthornchai
Aquatic Molecular Genetics and Biotechnology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Rd., Klong 1, Klongluang, Pathumthani, 12120, Thailand.
Sage
S
Chaiyapechara
Interdisciplinary Graduate Program on Maritime Administration, Graduate School, Chulalongkorn University, Bangkok, 10330, Thailand.
Padermsak
P
Jarayabhand
Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36, Uppsala, Sweden.
Kenneth
K
Söderhäll
Aquatic Molecular Genetics and Biotechnology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Rd., Klong 1, Klongluang, Pathumthani, 12120, Thailand; Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36, Uppsala, Sweden; Fish Vet Group Asia Limited, 99/386, Chaengwattana Rd., Toongsonghong, Laksi, Bangkok, 10210, Thailand.
Pikul
P
Jiravanichpaisal
D000818:Animals; D004848:Epithelium / Q000502:physiology; D041981:Gastrointestinal Tract / Q000382:microbiology*; D054884:Host-Pathogen Interactions; D033561:Penaeidae / Q000382:microbiology*; D013499:Surface Properties; D014733:Vibrio / Q000502:physiology*