# Microbial Life on the Surface of Microlgistics in Natural Waters
## 4 Microplastics for Human and Animal Pathogens Colonization  
It was suggested that drifting plastic debris is a potential vector for spreading of a harmful microalga [79]. A similar question applies to the role of microplastics in relation to microorganisms. It is considered that microorganisms in microplastic-associated biofilms have an important role in pathogens transfer. The microbial biofilm formed on microplastics particles is called \"plastisphere\", a term which was proposed by [PERSON] with coauthors [80]. Plastisphere in ocean water had in its composition mainly members of the phylum _Proteobacteria_ (31-45%) which may include pathogenic species [81]. Potentially pathogenic _Vibrio_ spp., Gram-negative bacteria, facultative anaerobes, typically living in saline environment, several species of which could cause foodborne diseases to animals and humans, have been detected on the polypropylene debris from the North Atlantic [80] and on the floating microplastic particles (polyethylene, polypropylene and polystyrene) in the North and Baltic Sea [82]. It was found that bacteria from the family _Burkholderiaceae_ were present in the biofilms covered polyethylene terephthalate placed in the river [74]. The amount of bacteria from order _Burkholderiales_ was much higher on plastic particles such as polyethylene, polypropylene and polystyrene than on natural and inert substratesplaced in ambient Baltic bacterioplankton for 2 weeks [83]. Meanwhile some strains from the genus _Burkholeria_ are opportunistic pathogens of humans [84]. Biofilm-coated microplastics which have taste, smell, color, and have a size similar to plankton, are attractive for consumption by aquatic animals especially if food resources in the surrounding environment are scarce [85]. A lot of marine species are harmed and even killed by using plastic debris which poses a threat to their survival. Additionally, microorganisms including pathogens are concentrated on plastic particles, and consumption of such litters could infect the host. A plastic particle consumed by ocean habitat passes through its gut remaining intact and being excreted serves as a source of nutrients to microbiota of biofilm covered the plastic debris including the opportunistic pathogens such as _Vibrio_ spp., that survive in the animal digestive tract [78]. Disposal waters from wastewater treatment plants could be another source of potential pathogens to freshwater bodies [86]. It was shown that microplastic could be carriers of _Vibrio_ in waters with salinity even higher than 26% which poses a risk for marine environments [87]. Bacterial assemblages colonizing microplastic within the river included plastic decomposing organisms and pathogens [73]. Members of the family _Campylobacteraceae_, microaerophilic Gram-negative bacteria, which can be causative agents of enteritis in humans were found on microplastics in the river in Chicago, USA [77]. Analysis of biofilms of food-related marine macroplastic litter collected from zone of the shoreline on the Northern Ireland that was above water at low tide and underwater at high tide, showed the presence of such Gram-negative potential pathogenic bacteria: _Achromobacter xylosoxidants_ (agent of respiratory infections); _Aeromonas salmoniciida_ sp. _salmoniciida_ (pathogen in cultured and wild salmonid causing furunculosis); _Ervinia rhapontici_ (an opportunistic plant pathogen); _Lelliotta amnigena_ (infrequent opportunistic in humans causing urinary tract infection); _Neisseria flava_, _N. perflava_, _N. subflav_ (rare opportunistic pathogens of humans); _Pantoea agglomerans_ (plant pathogen and opportunistic human pathogen); _Providencia rettgeri_ (urinary tract and eye infections); _Pseudomonas fluorescens_ (rare affects patients with compromised immune systems); _Ps. chlororaphis_ (rarely pathogenic); _Ps. olevorans_ (rarely pathogenic); _Ps. viridifava_ (plant pathogen); _Ralunchia aquatilis_ (a causal agent of bacteremia in humans), and _Serratia fonctic_ (cause of skin and soft tissue infections) [88].