Occurrence and Inactivation of Emerging Pathogens in the Environment.

Persistent Link:
http://hdl.handle.net/10150/194623
Title:
Occurrence and Inactivation of Emerging Pathogens in the Environment.
Author:
Sarkar, Payal
Issue Date:
2008
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Emerging pathogens are organisms whose incidence has increased within the past two decades. In the last 40 years, several pathogens have emerged to cause infectious waterborne and foodborne diseases, thus causing a significant public health concern. Enterobacter sakazakii and Naegleria fowleri are emerging pathogens that have been documented to cause fatal infections. E. sakazakii is an emerging foodborne pathogen that represents a significant health risk by causing infections resulting in septicemia, meningitis and necrotizing enterocolitis in neonates, premature infants and also elderly immunocompromised individuals. Naegleria fowleri is a water-based protozoan flagellate that is the cause of primary amoebic meningoencephalitis; a fatal disease that mostly infects children and young adults through water-related recreational activities. The focus of this dissertation is to identify environmental reservoirs of Enterobacter sakazakii and to determine inactivation strategies to control Naegleria fowleri by chlorine and ultraviolet disinfection. In Appendix A, samples from various household kitchens were collected to determine the presence of E.sakazakii. The highest percentage of E.sakazakii was isolated from kitchen sponges (8%; n=50) and dishrags (10%; n=50). This study provided information on the presence of E.sakazakii on environmental surfaces in the kitchen. In Appendix B, our recent research has determined that N. fowleri is present in 8% (n=143) of municipal drinking water wells in central and southern Arizona. Therefore, guidelines need to be established for treatment of water with various disinfectants to control the growth and proliferation of N.fowleri. In Appendix C, the Ct values (concentration (mg/l) × exposure time) for chlorine inactivation of N. fowleri trophozoites and cysts were determined using the Efficiency Hom Kinetic Model (EHM). The Ct values for 99% inactivation of trophozoites and cysts were estimated to be 9 and 31, respectively. The ultraviolet light dose required for the 99% inactivation of N.fowleri trophozoites and cysts was determined to be 63 mW.sec/cm² and 13 mW.sec/cm², respectively.
Type:
text; Electronic Dissertation
Keywords:
Occurrence; Emerging Pathogens; Inactivation; Naegleria fowleri; Enterobacter sakazakii
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Microbiology & Immunology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Gerba, Charles P.
Committee Chair:
Gerba, Charles P.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleOccurrence and Inactivation of Emerging Pathogens in the Environment.en_US
dc.creatorSarkar, Payalen_US
dc.contributor.authorSarkar, Payalen_US
dc.date.issued2008en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractEmerging pathogens are organisms whose incidence has increased within the past two decades. In the last 40 years, several pathogens have emerged to cause infectious waterborne and foodborne diseases, thus causing a significant public health concern. Enterobacter sakazakii and Naegleria fowleri are emerging pathogens that have been documented to cause fatal infections. E. sakazakii is an emerging foodborne pathogen that represents a significant health risk by causing infections resulting in septicemia, meningitis and necrotizing enterocolitis in neonates, premature infants and also elderly immunocompromised individuals. Naegleria fowleri is a water-based protozoan flagellate that is the cause of primary amoebic meningoencephalitis; a fatal disease that mostly infects children and young adults through water-related recreational activities. The focus of this dissertation is to identify environmental reservoirs of Enterobacter sakazakii and to determine inactivation strategies to control Naegleria fowleri by chlorine and ultraviolet disinfection. In Appendix A, samples from various household kitchens were collected to determine the presence of E.sakazakii. The highest percentage of E.sakazakii was isolated from kitchen sponges (8%; n=50) and dishrags (10%; n=50). This study provided information on the presence of E.sakazakii on environmental surfaces in the kitchen. In Appendix B, our recent research has determined that N. fowleri is present in 8% (n=143) of municipal drinking water wells in central and southern Arizona. Therefore, guidelines need to be established for treatment of water with various disinfectants to control the growth and proliferation of N.fowleri. In Appendix C, the Ct values (concentration (mg/l) × exposure time) for chlorine inactivation of N. fowleri trophozoites and cysts were determined using the Efficiency Hom Kinetic Model (EHM). The Ct values for 99% inactivation of trophozoites and cysts were estimated to be 9 and 31, respectively. The ultraviolet light dose required for the 99% inactivation of N.fowleri trophozoites and cysts was determined to be 63 mW.sec/cm² and 13 mW.sec/cm², respectively.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectOccurrenceen_US
dc.subjectEmerging Pathogensen_US
dc.subjectInactivationen_US
dc.subjectNaegleria fowlerien_US
dc.subjectEnterobacter sakazakiien_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMicrobiology & Immunologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorGerba, Charles P.en_US
dc.contributor.chairGerba, Charles P.en_US
dc.contributor.committeememberPepper, Ianen_US
dc.contributor.committeememberBernstein, Harrisen_US
dc.contributor.committeememberReynolds, Kellyen_US
dc.identifier.proquest2887en_US
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