MICROBIOLOGY OF WATERBORNE DISEASES Microbiological Aspects and Risks Second Edition STEVEN L. PERCIVAL Surface Science Research Centre and Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK MARYLYNN V. YATES Department of Environmental Sciences, University of California, Riverside, California, USA DAVID W. WILLIAMS School of Dentistry, Cardiff University, Cardiff, South Glamorgan, UK RACHEL M. CHALMERS Cryptosporidium Reference Unit, Singleton Hospital, Swansea, UK NICHOLAS F. GRAY School of Natural Science, Trinity College, Dublin, Ireland Amsterdam(cid:129)Boston(cid:129)Heidelberg(cid:129)London NewYork(cid:129)Oxford(cid:129)Paris(cid:129)SanDiego SanFrancisco(cid:129)Singapore(cid:129)Sydney(cid:129)Tokyo AcademicPressisanimprintofElsevier Academic Press isan imprint of Elsevier 32 Jamestown Road, LondonNW1 7BY,UK 225 Wyman Street, Waltham, MA 02451, USA 525 B Street, Suite 1800, San Diego, CA92101-4495, USA Second edition 2014 Copyright (cid:1) 2014 Elsevier Ltd. Allrights reserved. Nopartofthispublicationmaybereproduced,storedinaretrievalsystemortransmittedinany formorbyanymeanselectronic,mechanical,photocopying,recordingorotherwisewithoutthe prior written permission of the publisher. 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British Library Cataloguing-in-Publication Data Acatalogue record for this book isavailable from the BritishLibrary Libraryof Congress Cataloging-in-Publication Data Acatalogrecord for this bookisavailable from theLibrary of Congress ISBN: 978-0-12-415846-7 For information on all AcademicPress publications visit our website at elsevierdirect.com TypesetbyTNQ Books and Journals Pvt Ltd www.tnq.co.in Printed and bound inGreat Britain 14 15 16 17 18 10 9 8 7 6 5 43 2 1 PREFACE Waterborne diseases, specifically those caused by unsafe drinking water, present a serious global health threat. Understanding the pathogens that cause these diseases can helpustodevelopbetter preventativeandcontrolmethodsglobally.The2ndeditionof TheMicrobiologyofWaterborne Diseasesisacomprehensivetextthatprovidesan in-depth account of all aspects of waterborne pathogens of public health significance. Sectiononeofthebookdiscusseswaterbornepathogensandtherolebiofilmsplayin their survival and dissemination. Sections two, three and four highlight the major bac- terial, viral and protozoa associated with water. Each pathogen-specific chapter covers thefundamentalsofmicrobiologyofeachpathogenincludingtheirsurvivalandcontrol inbiofilms,andanewsectionhighlightingmethodsthathavebeenusedforcontrol.In addition, each chapter highlights methods that have been employed for detecting each waterborne pathogen and the risks each pathogen presents to water users is also dis- cussed. Section four of the book provides an overview of the methods employed for microbial control with the final section of the book highlighting the implications of global warming and climate on waterborne diseases. This updated reference will continue to serve as an indispensable reference for mi- crobiologists, public health officials, water and wastewater treatment professionals, en- gineers, environmental health officers and students in the infectious disease fields. Professor Steven L. Percival The University of Liverpool j xvii DEDICATION Steven Percival would like to dedicate this book to Carol, Alex, Tom, Mum and Dad. Thank you! RachelChalmerswouldliketodedicatethisbooktothememoryofJoanShieldswhose work contributed much to our understanding of protozoan parasites in drinking and recreational waters. DavidWilliamswouldliketodedicatethisbooktoLorna,Daniel,AilishCalum,Sioned and Anne. In memoryof Eirwyn. Nick Gray would like to dedicate this book to Lucy, Catriona and Rebecca. j xix CONTRIBUTORS Mark Burr Research Assistant Professor, Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, USA Alison Burrells Moredun Research Institute, Penicuik, Midlothian, Scotland Anne Camper Professor, Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA Rachel M. Chalmers Head of Cryptosporidium Reference Unit, Public Health Wales, Singleton Hospital, Swansea, UK Nicholas F. Gray ProfessorofEnvironmentalSciences,CentrefortheEnvironment,SchoolofNaturalSciences, Trinity College, University of Dublin, Dublin 2, Ireland Frank Katzer Moredun Research Institute, Penicuik, Midlothian, Scotland Andreas Nocker Lecturer in Drinking Water Microbiology, Cranfield Water Science Institute, School of Applied Sciences, Cranfield University, Cranfield, UK Marieke Opsteegh Veterinary Epidemiologist, Laboratory for Zoonoses and Environmental Microbiology, Bilthoven, The Netherlands Steven L. Percival Professorof Microbiologyand Anti-infectives,Surface Science ResearchCentreand Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK Lucy J. Robertson Professor, Parasitology Laboratory, Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway David W. Williams Professor of Oral Microbiology, Tissue Engineering & Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff, UK Peter Wyn-Jones Professor, Institute of Pharmacy, Chemistry and Biomedical Sciences, Universityof Sunderland, UK j xxi xxii Contributors Marylynn V. Yates Professor, College of Natural and Agricultural Sciences, University of California, Riverside, California, USA CHAPTER ONE fi Pathogens in Water and Bio lms Andreas Nocker*, Mark Burr**, Anne Camper*** *LecturerinDrinkingWaterMicrobiology,CranfieldWaterScienceInstitute,SchoolofAppliedSciences, CranfieldUniversity,Cranfield,UK **ResearchAssistantProfessor,DepartmentofLandResourcesandEnvironmentalSciences,MontanaStateUniversity, Bozeman,Montana,USA ***Professor,CenterforBiofilmEngineering,MontanaStateUniversity,Bozeman,Montana,USA INTRODUCTION As for any other organism, the goal of a waterborne pathogen is to propagate and disseminate itself. The place where propagation occurs and the mode of dissemination have important implications. Some pathogens spend most of their lives in thewaterenvironmentand only coincidentallyencountera host. Theyaretypically well adapted to the low nutrient concentrations and physical, chemical and biological conditions encountered in water. Water can be seen as their natural habitat and propagation can occur both in water and in the host. Examples of these so-called ‘environmental pathogens’ are Legionella spp., Pseudomonas aeruginosa, some Mycobacteria species and N. fowleri. These pathogens are characterized by their facul- tative host-independence. For other waterborne pathogens (‘obligate pathogens’), propagationcanonlyoccur inaninfectedhost.Replicationtypicallyoccursinsidethe intestines of infected individuals. Examples of such ‘enteric’ pathogens include Campylobacter, Salmonella, Cryptosporidium, Giardia and all of the enteric viruses. To disseminate themselves, they depend on being shed by the host into the environment as a means to reach other hosts. They can be referred to as ‘environmentally- transmitted pathogens’. Such pathogens typically have two lifestyles, one inside the affected human or animal host and one in the environment. Whereas their role and survival in patients have received much attention from clinical microbiology and are partly understood, there is limited knowledge about their ecological niches and survival under the conditions they encounter in the environment. Among the envi- ronmental niches which these pathogens might occupy during their life cycle outside the host, water plays an important role for many of them, which is not surprising considering the efficiency of water as a transmission vehicle. How much of its life cycle apathogenspendsinwaterandhow long itsurvivesin waterdependsgreatlyon the pathogen. For some pathogens, like Giardia or Cryptosporidium that are shed as resistant cysts oroocysts, water might allow survival forextended periods of time. For otherswater might be seen more as a ‘necessary choice’ fordissemination, rather than MicrobiologyofWaterborneDiseases (cid:1)2014ElsevierLtd. j ISBN978-0-12-415846-7,http://dx.doi.org/10.1016/B978-0-12-415846-7.00001-9 Allrightsreserved. 3 4 AndreasNocker,MarkBurrandAnneCamper their preferred environment, implyingthat their survivalin water is limited. For some pathogens like Vibrio cholera and Escherichia coli O157, which were previously believed to strictly replicate in the host, growth in water has been demonstrated under special conditions (Vital et al., 2007; 2008). Although it is tempting to imagine microorganisms in water as planktonic cells surroundedbywater,microbiologyhasreachedapointwherepathogensareincreasingly seeninanecologicalcontext.Thelast20yearshaverevealedthatmuchofmicrobiallife occurs in biofilms (Costerton et al., 1999). Waterborne pathogens are unlikely to be an exception, as congregation and integration into biofilms can offer considerable advan- tages. The inaccessibilityof pathogens in biofilms poses a serious challenge to sampling anddetection,buthasimportantimplicationsfortheirecologyandsurvival.Thischapter will addresshoweffectively pathogens can associatewith biofilms and will discuss some of the important questions related to this association. In practical terms, the most importantconsequenceistheshelterprovidedbythebiofilmmicroenvironmentandthe resulting increased resistance to stress factors and disinfection. Biofilmscanalsobeconsideredtobethelocationwheredifferentspeciescomeinto close contact, which enables communication, transfer of genetic material, and even internalization of smaller microorganisms (bacteria and possibly viruses) by protozoan predatorsgrazingonbiofilms.Fourdifferentscenariosofexistenceareconsideredinthis chapter for waterborne pathogens: the planktonic form, an intracellular lifestyle within protozoan hosts, and the association with biofilms and with organic/inorganic partic- ulate material (Fig. 1.1). The ‘lifestyle’ has important implications for the pathogen’s phenotype and survival in water. Lastbutnotleast,thischapteraddressestheimplicationsofthenon-planktonicexistence forinfectivity.Thedramaticallyhighermicrobialdensitywithinabiofilmcomparedtothe planktoniclifestylemaybehighlybeneficialindeliveringaninfectivedosesufficientlylarge Figure 1.1 Schematic diagram of three different distinct environments pathogens can live in: (A) planktonicmicrobialflorawithdispersedpathogens;(B)internalizedpathogenslivingintracellularly withinprotozoanhosts;(C)pathogensembeddedinabiofilmcommunity;and(D)attachedtopar- ticles. Pathogens are symbolized by filled areas. Whereas the diagrams represent the most distinct scenarios,combinationsofsuchconditionsarelikely.Itcanbeassumedthatthedifferentenviron- mentsgreatlyinfluencethesurvivalofthepathogens. PathogensinWaterandBiofilms 5 to overcometheimmunesystemofpersonsconsumingmicrobially-contaminatedwater. Furthermore, biofilms may be hotspots for differentiation because they create heteroge- neity.For pathogensthishasaspecialmeaningasitcanincreasevirulence. BIOFILM FORMATION AND PATHOGEN ADHESION TO BIOFILMS Althoughbiofilmscanharbourawidespectrumofmicroorganisms,itisimportant torealizethatitisthebacteriawhichareprimarilyresponsibleforlayingthefoundation stones for the microbial city. In contrast with viruses and protozoa, only bacteria and algae have the ability to actively form biofilms byattaching to surfaces and by secreting ‘glue’intheformofexopolysaccharides.Thisslimycoatingcan,however,offerarefuge fororganismsthatarenotabletoactivelyformbiofilms,includingvirusesandprotozoa or bacteria with weak biofilm formation capacity. Ongoing attachment and intra- and interspecies communication ultimately lead to the formation of complex microbial communitiesthathostalargespectrumofmicroorganisms,possiblyincludingpathogens. Ability for De Novo Biofilm Formation Likeotherbacteriathatarenaturallypresentinwaterorthatareintroducedintoawater body,manypathogenscaneitheractivelyformbiofilmsthemselvesorattachtoexisting biofilms. The processes are referred to as primary or secondary colonization (Szewzyk et al., 2000; Donlan, 2002). Biofilm formation is not only the transition from free- floating to sessile, but has far-reaching physiological consequences. Surface attachment is typically accompanied by a change in cellular physiology (Larsson et al., 2008). ComparingtheproteomesofPseudomonasaeruginosaplanktoniccellsandcellsinamature biofilm, Sauer et al., (2002) reported a six-fold or greaterchange in expression level for more than 800 proteins (equivalent to more than 50% of the proteome). Multiple phenotypes were observed during biofilm development. ExamplesofpathogensthatweredescribedtoactivelyformbiofilmsincludeVibrio choleraandHelicobacter pylori.WhenVibriocholeracellsaregrownoncultureplates,two morphologically distinct colony types can be differentiated: smooth and rugose. The phenotypes differ in their biofilm-forming capacity, with the rugose variant showing increased production of polysaccharides and enhanced ability to form biofilms (Yildiz &Schoolnik1999).For H.pyloriitwasshownthatbiofilmsareformedintheabsence of other species at the air-liquid interface of batch cultures (Cole et al., 2004; Stark etal.,1999).Monospeciesbiofilmscontainedchannelsfornutrientflowandhadtypical biofilm features. One the most efficient biofilm formers might be the opportunistic pathogen P. aeruginosa, which has evolved into the model species for biofilm research. The ability to form de novo biofilms does not only substantially vary between different species, but can also significantly vary between different strains of the same species