Extracellular excystation and development of Cryptosporidium: tracing the fate of oocysts within Pseudomonas aquatic biofilm systems

BMC Microbiology

Research Article

Peta L Clode¹  Andrew Thompson²  Hanna Edwards²  Wan Koh³  Paul Monis⁴ 

[1] Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, 35 Stirling Hwy, 6009, Crawley, WA, Australia;School of Veterinary and Life Sciences, Murdoch University, South Street, 6150, Murdoch, WA, Australia;School of Veterinary and Life Sciences, Murdoch University, South Street, 6150, Murdoch, WA, Australia;School of Occupational and Public Health, Ryerson University, 350 Victoria Street, M5B2K3, Toronto, Ontario, Canada;South Australian Water Corporation, 250 Victoria Square, 5000, Adelaide, SA, Australia;

关键词: Cryptosporidium;    Biofilms;    Extracellular multiplication;    Excystation;    Confocal microscope;    Scanning electron microscope;    Flow cytometry;   

DOI  :  10.1186/s12866-014-0281-8

 received in 2014-07-30, accepted in 2014-10-30,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundAquatic biofilms often serve as environmental reservoirs for microorganisms and provide them with a nutrient-rich growth environment under harsh conditions. With regard to Cryptosporidium, biofilms can serve as environmental reservoirs for oocysts, but may also support the growth of additional Cryptosporidium stages.ResultsHere we used confocal laser scanning microscopy, scanning electron microscopy (SEM), and flow cytometry to identify and describe various Cryptosporidium developmental stages present within aquatic biofilm systems, and to directly compare these to stages produced in cell culture. We also show that Cryptosporidium has the ability to form a parasitophorous vacuole independently, in a host-free biofilm environment, potentially allowing them to complete an extracellular life cycle. Correlative data from confocal and SEM imaging of the same cells confirmed that the observed developmental stages (including trophozoites, meronts, and merozoites) were Cryptosporidium. These microscopy observations were further supported by flow cytometric analyses, where excysted oocyst populations were detected in 1, 3 and 6 day-old Cryptosporidium-exposed biofilms, but not in biofilm-free controls.ConclusionsThese observations not only highlight the risk that aquatic biofilms pose in regards to Cryptosporidium outbreaks from water distribution systems, but further indicate that even simple biofilms are able to stimulate oocyst excystation and support the extracellular multiplication and development of Cryptosporidium within aquatic environments.

【 授权许可】

CC BY   
© Koh et al.; licensee BioMed Central Ltd. 2014