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Water MicrobiologyMicrobial Contaminants

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Title: Water MicrobiologyMicrobial Contaminants


1
Water Microbiology/Microbial Contaminants
Gwy-Am Shin Office Suite 2335, 4225
Roosevelt Phone 206-543-9026 Email
gwyam_at_u.washington.edu
2
Microbiological Contaminants
  • Most benign, normal
  • Some are frank pathogens
  • Microbial pathogens usually are not normal
    flora of humans Oppurtunisitic pathogens
  • Some are normal flora of animals
  • Salmonella enteriditis and Campylobacter jejuni
    in poultry
  • Normal flora for local populations may be
    pathogenic for visitors and transient
    populations
  • Travellers diarrhea due to local strains of E.
    coli
  • Some normal flora are pathogenic for sensitive
    populations, such as immunocompromised persons

3
Occurrence of Enteric Microbial Pathogens in
Humans and Pathogen Shedding
  • Enteric (gastrointestinal) illnesses are second
    only to respiratory illnesses in the population
  • Most people get 1 enteric illness per year
  • Annual illness rates are even higher in infants,
    children, the elderly, child caregivers, health
    professionals, the poor, male homosexuals and
    other high risk groups
  • Not all enteric infections produce illness
    (asymptomatic or sub-clinical infections)
  • So, rates of infection are even higher (by
    perhaps 2 to 100 times)
  • People (and animals) with enteric infections
    fecally excrete high concentrations of pathogens
    for days, weeks, months or longer.
  • Pathogen concentrations can be gt106 to gt109 per
    gram of feces.
  • Community pathogen shedding is often 1-10 at any
    time.

4
Transmission of enteric pathogens
5
Incidence and concentration of enteric pathogens
in feces (USA)
6
Viruses smallest (0.02-0.3 µm diameter)
simplest nucleic acid protein coat (
lipoprotein envelope) Bacteria 0.5-2.0 µm
diameter prokaryotes cellular simple internal
organization binary fission. Protozoa most gt2
µm- 2 mm eucaryotic uni-cellular
non-photosynthetic flexible cell membrane no
cell wall wide range of sizes and shapes hardy
cysts Groups flagellates, amoebae, ciliates,
sporozoans (complex life cycle) and
microsporidia. , rigid cell wall, most eukaryotic
Algae wide range of sizes and shapes
photosynthetic. Helminths (Worms) multicellular
animals some are parasites eggs are small
enough (25-150 µm) to pose health risks from
human and animal wastes in water.
7
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8
THE MICROBIAL WORLD SIZES OF MICROBES
Parasites are visible by light microscopy
9
Viruses
  • Smallest (0.02 0.3 µm)
  • Simplest
  • Nucleic acids (DNA or RNA)
  • Protein capsid

10
Human enteric viruses
11
Bacteria
  • Size 0.5 2.0 µm
  • Simple internal organization
  • Envelope cytoplasmic membrane, cell wall, and
    capsule
  • Appendages flagella and/or pili
  • Spores environmentally resistant form

12
Human pathogenic bacteria
13
Human pathogenic bacteria
14
Procaryotic Cell (left) and Eucaryotic Cell
(right)
15
Protozoa
  • Size 2 2000 µm
  • Complex internal organization (nucleus,
    mitochondria, etc)
  • Very complex life cycle (inside and outside of
    their hosts)
  • Flagellates, amoeba, ciliates, and sporozoans
  • (Oo)cysts environmentally resistant form

16
Human protozoan parasites
17
Algae
  • Photosynthetic
  • Rigid cell wall
  • Wide range of sizes and shapes
  • 2 micrometers and larger

Nostoc
Anabaena and Aphanocapsa
18
Helminths (Worms)
  • Multicellular animals
  • Some are human and/or animal parasites
  • Eggs are small enough to pose environmental
    health problems from human and animal excreta in
    water, food, soil, etc.
  • Several major groups
  • Nematodes (roundworms) ex. Ascaris
  • Trematodes (flukes flatworms) ex. Schistosomes
  • Cestodes (tapeworms) pork and beef tapeworms

19
Helminths
  • Multicellualr animals
  • Size up to 30 cm
  • Highly differentiated structures
  • Very complex life cycle (inside and outside of
    their hosts)
  • Nematodes, Trematodes, and Cestodes
  • Eggs environmentally resistant form

20
Human helminth parasites
21
Bacteria
22
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23
Shigella spp.
  • Elongated and straight rods
  • Size 0.5-1 µm
  • Four species dysenteriae, flexneri, sonnei, and
    boydii
  • Watery or bloody diarrhea, abdominal pain, fever,
    and malaise
  • fatality may be as high as 10-15 with some
    strains

24
Shigella spp. Epidemiology
  • Involved in 44 drinking water outbreaks with
    9,196 cases and 34 recreational water outbreaks
    with 2,329 cases in USA (1971-2000)
  • Incidence
  • 14,000 (lab-confirmed) and 448,240 (estimated)
    cases in USA
  • 164.7 million (estimated) case (163.2 in
    developing countries and 1.5 in developed
    countries) and 1.1 million death worldwide
  • 580,000 cases in travelers
  • Reservoirs humans and primates
  • Infectious dose 10 cells
  • Incubation period typically 1-3 days
  • Duration of illness 2-7 days
  • Mode of transmission Direct (person-to-person)
    and indirect (fomites, water, and food)

25
Escherichia coli O157 H7
  • Elongated and straight rods
  • Size 0.5-1 µm
  • 8,000 serotypes
  • Acute bloody diarrhea and abdominal cramps with
    little or no fever
  • 3-5 fatality.

26
Escherichia coli O157 H7 Epidemiology
  • Involved in 11 drinking water outbreaks with 529
    cases and 15 recreational water outbreaks with
    387 cases in USA (1971-2000)
  • Incidence
  • 730,000 (estimated) cases (USA)
  • 210 million cases and 300,000 deaths worldwide
  • Many different serotypes enterotoxigenic (ETEC)
    enteropathogenic (EPEC) enteroinvasive (EIEC)
    and enteroaggregative (EAgg EC)
  • All pathogenic E. coli 1.5 billion (estimated)
    case and 3 million death worldwide
  • Reservoirs humans and animals (cattle, goats,
    sheep, deer, .)
  • Infectious dose 100 cells
  • Incubation period typically 1-3 days
  • Duration of illness 2-12 days
  • Mode of transmission Direct (person-to-person)
    and indirect (fomites, water, and food)

27
Salmonella spp.
  • Elongated and straight rods
  • gt2,000 serotypes
  • Diarrhea, fever, headache, constipation, malaise,
    chills, and myalgia
  • 12 - 30 mortality

28
Salmonella spp. Epidemiology
  • Involved in 12 drinking water outbreaks with
    2,370 cases in USA (1971-1992)
  • Incidence
  • An estimated1.4 million cases with 500 death in
    the United States
  • An estimated 21 million cases of typhoid fever
    and 200,000 deaths occur worldwide.
  • Reservoirs humans and animals (cattle, chicken,
    turkey)
  • Infectious dose 100 cells
  • Incubation period typically 1-3 days
  • Duration of illness 2-7 days
  • Mode of transmission Direct (person-to-person)
    and indirect (fomites, water, and food)

29
Vibrio cholerae
  • Straight or curved rods
  • Motile with flagella
  • 0.5-0.8 µm in width and 1.4-2.6 µm in length
  • Serogroup O1 or O139
  • Profuse watery diarrhea, vomiting, circulatory
    collapse and shock.
  • 40 - 60 of typical cases are fatal if untreated

30
Vibrio spp. Epidemiology
  • Involved in 2 drinking water outbreaks with 28
    cases in the USA (1971-2000)
  • Incidence
  • 0-5 cases per year in the United States.
  • A major cause of epidemic diarrhea throughout the
    developing world.
  • Ongoing global pandemic in Asia, Africa and Latin
    America for the last four decades.
  • Reservoirs humans, environmental reservoirs -
    waters may be associated with copepods or other
    zooplankton
  • Infectious dose 100 cells
  • Incubation period a few hours to 5 days usually
    2-3 days
  • Duration of illness several days
  • Mode of transmission Indirect (water and food)

31
Campylobacter spp.
  • Curved rod
  • Size 1.5-3 microns
  • C. jejuni and C. coli
  • fever, nausea, abdominal cramps, (seldom)
    vomiting, and bloody diarrhea

32
Campylobacter spp. Epidemiology
  • Involved in 16 drinking water outbreaks with
    5473 cases in the USA (1971-2000)
  • Incidence
  • An estimated 2.4 million persons are affected
    each year.
  • Reservoirs humans and animals (cattle, chicken,
    birds, )
  • Infectious dose 100 cells
  • Incubation period 3-5 days
  • Duration of illness 2-10 days
  • Mode of transmission Direct (animal contact) and
    indirect (food and water)

33
Other Important Bacterial Pathogens
  • Fecal origin
  • Aeromonas spp.
  • Plesomonas spp.
  • Yersinia spp.
  • Environmental origin
  • Legionella spp. (esp. L. pneumophila)
  • Pseudomonas spp. (esp. P. aeruginosa)
  • Mycobacterium Avium Complex (MAC)

34
Nuisance Bacteria
  • Acintomycetes/Streptomycetes
  • Thin filamentous, gram postive rods
  • Taste and odor
  • Iron Bacteria
  • E.g. Leptothrix, Thiobacillus, Clonothrix,
    Sphaerotilus, Caulobacter, Hyphomicrobium
  • Main corrosion
  • Increase oxidant demand
  • Sulfur Bacteria
  • E.g. Desulfovibrio, Thiothrix, Chlorobium,
    Chromatium, Thiobacillus
  • Formation of tubercles pipe corrosion increase
    oxidant demand
  • Reduce Sulfur compounds to H2Sa
  • Nitrifying bacteria
  • E.g. Nitrosomonas, Nitrobacter, Nitrospira,
    Nitrococcus
  • Increased oxygen demand (Nitrite)

35
Protozoan Pathogens
36
Waterborne Outbreaks in the United States,
1989-1994
Etiologic Agent No. Outbreaks No. Cases Acute GI
(unknown) 44 16,264 Cryptosporidium
parvum 8 406,822 Giardia lamblia 16 1,205 Hepat
itis A virus 4 81 Norwalk-like
viruses 1 900 E. coli O157H7 1 243 Cyclospora
cayatenensis 1 21 Shigella spp. 7 570 Salmonell
a sp. 1 625 Vibrio cholerae (non-01) 1 11 Chemi
cals Pb, NO3, F and Cu 13 394 TOTAL 87 427,
256
37
Protozoa
  • Size
  • Usually 10-50 µm
  • smallest 1-10 µm, largest 150 µm (Balantidium
    coli)
  • Many organells
  • Nucleus (or nuclei)
  • Cytosome (cell mouth), food vacuoles, contractile
    vacuoles (osmoregulation), Golgi apparatus,
    mitochondria, lysosomes,
  • Locomotive structures pseudopodia, flagella,
    cilia
  • Cell cycle and reproduction
  • Asexual (binary fission) and sexual (various life
    stages)

38
Prokaryotic Cell (left) and Eukaryotic Cell
(right)
39
Enteric Protozoans Taxonomy
  • Protozoans (single-celled)
  • Sarcodina Amoebas ex. Entamoeba histolytica
  • Mastigophora Flagellates ex. Giardia lamblia
  • Sporozoa Coccidians Cryptosporidium parvum
  • Ciliophora Ciliates ex. Balantidium coli
  • Microsporidia ex. Enterocytozoon beinusi

40
Entamoeba histolytica
  • Ameba
  • Cyst
  • 10-20 µm
  • 4 nuclei
  • chromatoidal bars
  • Trophozoite
  • 12-50 µm
  • 1 nucleus
  • actively mobile
  • Mild GI symptoms (abdominal pain, cramps, colitis
    and diarrhea), bloody diarrhea (amoebic
    dysentery)

41
Entamoeba histolytica Epidemiology
  • Involved in 1 drinking water outbreaks with 4
    cases and 40 recreational water outbreaks with
    11,707 cases in USA (1971-2000)
  • Incidence
  • 4 prevalence in USA
  • 50 prevalence with 100,000 deaths per year
    worldwide
  • Reservoir human is the only host
  • Infectious dose unknown however, theoretically,
    the ingestion of one viable cyst can cause
    infection
  • Incubation period 1-4 weeks
  • Transmission Direct transmission (sexually
    transmission), fecal-oral route, waterborne,
    foodborne
  • High risk groups travelers, recent immigrants,
    male homosexuals, institutioned populations

42
Giardia lamblia
  • Flagellate
  • Cyst
  • 8-14 µm
  • 2-4 nuclei
  • thick oocyst wall (0.3 µm)
  • Trophozoite
  • Heart-shaped, symmetric
  • 10-18 µm long, 6-8 µm wide
  • 2 nuclei
  • 8 flagella
  • abdominal cramps, nausea, vomiting, anorexia,
    low-grade fever, flu-like headache, general
    malaise, weakness, weight loss, distension, and
    profuse, greasy, bulky and foul-smelling diarrhea

43
Giardia lamblia Epidemiology
  • Involved in 126 drinking water outbreaks with
    28,426 cases and 16 recreational water outbreaks
    with 684 cases in USA (1971-2000)
  • 500,000 estimated cases (200 millions?) worldwide
  • Reservoir Human and animals (dogs, beaver,
    muskrat, elk, deer, voles, mice, horses, sheep,
    )
  • Infectious dose 10 cysts
  • Incubation period 1-14 days
  • Duration of illness 1-3 weeks
  • Transmission Fomites, waterborne, foodborne
  • High risk groups children (in day-care centers),
    immunosuppressed people, and institutioned
    populations

44
Cryptosporidium parvum
  • Coccidia
  • Oocyst
  • 4 - 6 ?m
  • 4 sporozoites
  • Thick oocyst wall
  • Sporozoite
  • No locomotive structure
  • Immunocompetent people similar to giardiasis
  • Immunocompromised people life-threating
  • Fluid loss 2-6liter/day (17 liters/day)
  • Extra-intestinal infection respiratory
    cryptosporidiosis (intestitial pneumonia)

45
Cryptosporidium parvum Epidemiology
  • Involved in 15 drinking water outbreaks with
    421,473 cases and 40 recreational water outbreaks
    with 11,707 cases in USA(1971-2000)
  • Incidence
  • 1 3 prevalence in USA
  • 5 (Asia) and 10 (Africa) prevalence
  • Reservoir Human and animals (calves, lambs,
    goats,horses, pigs, deer, squirrel, beaver,
    muskrat,woodchuck,rabbit, dogs, fox, cat, skunk,
    raccon, bear, )
  • Infectious dose lt 10 cysts
  • Incubation period 7 days
  • Duration of illness 1-4 weeks
  • Transmission Fomites, waterborne, foodborne
  • High risk groups children, immunosuppressed
    people, institutioned populations

46
Emerging Protozoan Parasites
  • Toxoplasma gondii
  • Microsporidia spp.

47
Toxoplasma gondii (oocysts)
  • Apicomplexa (Coccidia)
  • Oocyst
  • Two phases
  • A unsporulated
  • B sporulated
  • 10 13 ?m
  • two sporocysts
  • four sporozoites
  • distinctive cell walls
  • two or three layers
  • scatter UV
  • highly persistent in the environment
  • soil (months)
  • moist conditions (years)

48
Toxoplasma gondii (other infectious forms)
  • Tachyzoite
  • Crescent-shaped
  • 2X6 ?m
  • Rapidly multiflying
  • Transmitted through placenta
  • Bradyzoite
  • Slowly multiplying
  • Tissues in intermediate hosts
  • Reproduction
  • Both asexual (intermediate hosts) and sexual
    (definitive hosts cats)

49
Transmission of Toxoplasma gondii
50
Toxoplasma gondii Epidemiology
  • Worldwide
  • 22.5 prevalence (general population) in USA
    between 1988-1994
  • Half billion people in the world
  • Unusually high prevalence in France (65-85) raw
    or undercooked meat
  • High prevalence in Central America large number
    of stray cats
  • Symptoms
  • Immunocompetent people mostly asymptomatic, some
    flu-like symptoms (swollen lymph glands, muscle
    aches and pains)
  • Immunocompromised people life-threating
  • central nerve system disease (encephalitis)
  • blindness, myocarditis, pneumonia
  • Congenital infected children
  • impaired vision and mental retardation
  • Reservoir Definitive hosts are cats
    intermediate hosts are sheep, goats, rodents,
    swine, cattle, chicken, and birds
  • Infectious dose Not known
  • Incubation period 10-23 days
  • Transmission Indirect (water and food) and
    transplacental
  • High risk groups infants born to infected
    mothers, immunosuppressed people

51
Microsporidia spp.
  • New Phylum
  • 143 genera, gt1200 species
  • 14 identified human pathogens
  • Produce very resistant spores
  • Usuaually small (1-4 ?m)
  • A unique organalle (polar tubule)
  • Coiled inside the spores
  • Inject infective spore contents into the host
    cells

52
Life cycle of Microsporidia spp.
53
Microsporidia spp. Epidemiology
  • Worldwide
  • Both developed and developing countries
  • Symptoms
  • Immunocompetent people asymptomatic or
    self-limiting diarrhea
  • Immunocompromised people
  • Chronic diarrhea
  • Disseminated diseases (keraconjunctivitis,
    bronchitis, pnuemonia, hepatitis, )
  • Reservoirs human and animals (rabbits, mice,
    dogs, pigs, cats, cattle, wild birds (parrots),
    insects?)
  • Infectious dose Not known
  • Incubation period Not known
  • Transmission uncertain
  • Airborne transmission?
  • Waterborne transmission??
  • Transplacental transmission? (Encephalitozoon
    spp.)

54
Other Important Protozoa
  • Trypanosomes- Sleeping Sickness
  • African (Tsetse flies)
  • American (kissing bugs) Chagas
  • Acanthamoeba spp. (GAE)
  • Balamuthia mandrillaris (GAE)
  • Naeglaria fowlerii (PAM)
  • Pneumocystis carinii (now P. jiroveci a fungus)

55
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