Influence of adhesion to activated carbon particles on the viability of waterborne pathogenic bacteria under flow.
In rural areas around the world, people often rely on water filtration plants using activated carbon particles for safe water supply. Depending on the carbon surface, adhering microorganisms die or grow to form a biofilm. Assays to assess the efficacy of activated carbons in bacterial removal do not allow direct observation of bacterial adhesion and the determination of viability. Here we propose to use a parallel plate flow chamber with carbon particles attached to the bottom plate to study bacterial adhesion to individual carbon particles and determine the viability of adhering bacteria. Observation and enumeration is done after live/dead staining in a confocal laser scanning microscope. Escherichiae coli adhered in higher numbers than Raoultella terrigena, except to a coconut-based carbon, which showed low bacterial adhesion compared to other wood-based carbon types. After adhesion, 83-96% of the bacteria adhering to an acidic carbon were dead, while on a basic carbon 54-56% were dead. A positively charged, basic carbon yielded 76-78% bacteria dead, while on a negatively charged coconut-based carbon only 32-37% were killed upon adhesion. The possibility to determine both adhesion as well as the viability of adhering bacteria upon adhesion to carbon particles is most relevant, because if bacteria adhere but remain viable, this still puts the water treatment system at risk, as live bacteria can grow and form a biofilm that can then be shedded to cause contamination.
van der Mei
Henny C
HC
Department of Biomedical Engineering, University Medical Center Groningen, and University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands. h.c.van.der.mei@med.umcg.nl
Atema-Smit
Jelly
J
Jager
Debbie
D
Langworthy
Don E
DE
Collias
Dimitris I
DI
Mitchell
Michael D
MD
Busscher
Henk J
HJ
D000268:Adhesiveness; D001419:Bacteria / Q000737:chemistry* / Q000166:cytology*; D001422:Bacterial Adhesion / Q000187:drug effects; D018441:Biofilms / Q000254:growth & development; D002244:Carbon / Q000737:chemistry*; D003059:Cocos / Q000737:chemistry; D015169:Colony Count, Microbial; D009994:Osmolar Concentration; D055672:Static Electricity; D014865:Waste Disposal, Fluid / Q000379:methods; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods
D002244:Carbon