Nucleic acid fluorochromes and flow cytometry prove useful in assessing the effect of chlorination on drinking water bacteria.
Flow cytometry (FCM), combined with staining using two fluorochromes (propidium iodide, PI, or SYBR Green II RNA gel stain, SYBR-II), was used to assess nucleic acid injuries to chlorinated drinking water bacteria. Highly fluorescent SYBR-II-stained bacteria were converted to bacteria with low fluorescence after chlorination. PI staining of bacteria exposed to different doses of chlorine showed membrane permeabilisation ([Cl2] < 0.2 mg L(-1)) and nucleic acid damage at higher doses ([Cl2] > 0.3 mg L(-1)). Above a threshold dose (between 1.5 and 3 mg Cl2 L(-1)), nucleic acids appeared severely damaged and incapable of being stained by PI or SYBR-II. These results constitute evidence that FCM is a promising tool for assessing drinking water bacteria injuries and for controlling chlorine disinfection efficiency much more rapidly than the standard sensitive but time-consuming heterotrophic plate count method.
Phe
Meng-Huot
MH
Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME UMR 7564 CNRS-UHP, Pôle de l'Eau-15, F-54500 Vandoeuvre-lès-Nancy, France.
Dossot
Manuel
M
Guilloteau
Hélène
H
Block
Jean-Claude
JC
D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D002713:Chlorine / Q000633:toxicity*; D004396:Coloring Agents; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D009696:Nucleic Acids / Q000187:drug effects*; D009930:Organic Chemicals; D011419:Propidium; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods; D014881:Water Supply
D004396:Coloring Agents; D005456:Fluorescent Dyes; D009696:Nucleic Acids; D009930:Organic Chemicals; C098798:SYBR Green II; D011419:Propidium; D002713:Chlorine