COA270: Pathogenic Microbes

Pathogen

Pathogen

disease casuing microorganism

Frank pathogen

produce diseae in healthy and immunocompromised individuals

Opportunistic pathogens

normally causes diseae only in ummonocomprised individuals

Waterborne diseases

pathogens transmitted to host though ingesting contaimnated water

→ fecal oral route

Water-washed diseases

pathogen transfer through improper hygenie practices

Water-based diseases

causes by aquatic pathogens, pathogens that spend certian life cycle ins tages in water, or pathogens that depend on aquatic organisms to complete their life cycle

Water-related diseases

pathogens that are transmitted by insects that breed or live near water

ex: malaria, yellow fever, sleeping sickenss

Salmonella

gram negative rod bacteria
Transmission: fecal oral route

cause typhoid fever (S. typhi)

Salmonellosis

occurs when bacteria penetrate the gut lumen and enters the intestinal lining where an enterotoxin is produced and inflammation occurs

→ symptoms: nausea, vomiting diarrhea, cramps, fever

Escherichia Coli

Gram negative rod bacteria

normal microbe found in fastrointesntial tract of all warm blooded animals

transmtited via fecal oral route

Enterotoxigenic

type of ecoli that is the major cause fo traveler’s disease

→ occurs when visiting underdeveloped counries

→ cause by two toxins

→ species specific

Enteropathogenic

type of ecoli found in infants less than 1 year old

→ symptoms: watery diarrhead with mucus, infant summer diarrhea, fever, dehydration

Enteroinvasive

types of ecoli that contains a plasmid that invades cells that line the gastrointestial tract

associated with hamburgers and unpasterized milk

affects all age groups

symptoms: water stools, abdominal cramps

self limitng

Enterohemorrhaic

type of ecoli that produces Shigella toxin(E. Coli 0157: H7)

cause by verotoxins I and II coded by infecting prophages

associated with contaminated beef, water, raw milk, unpasteurized fruits and veggies

symptoms: watery stools that can become bloody

→ can escalate to hemolytic-uremic syndrome (renal failure and hemolytic anemia), neurological symptoms, and thrombotic thrombocyopenic purpura

S. dysentariae

most severe species of shigella

S. sonnei

most common shigella strain in the US

Shigella

human pathogen

transmission: fecal-oral route

more common in infants and elderly

associated with contaimnated water, raw vegetables, dairy products, and poultry

symptoms: GI track tissue destruction, ulceration, rectal bleeding, drastic dehydration

Campylobacter Jejuni

gram negatice curved rod bacteria

leading cause of bacterial diarrhea in the US

symptoms: muscle pain, abortion and enteritis in sheep and cattle

Yersinia

Gtam negative rod bacteria (small)

most are nonpathogenic

transmission: Pigs(Y. enterocolitica) and water, carrots, and icebery lettuce

Y. pseudotuberculosis

type of yersinia causes transmitted by water, carrots, and icebery lettuce

→ fever abdominal pain

Y. enterocolitica

pathogentic species of yersinia transmitted through pigs,

causes diaarrhea, bloody stool

Vibrio

gram negative comma shaped bacteria

transmission: fecal contaimined food, drinking water, undercooked seafood, raw oysters

can produe enterotoxin

V. parahaemolyticus

type of vibrio species that is transmitted by undercooked sea food

V. vulnificus

type of vibrio that is transmitted through raw oysters

most severe symptoms

symptoms: thrombocytopenia, bulbous skin lesions, shock, hypotension

V. cholerae

type of vibrio pathogen that is usually asymptomatic

can produce a enterotoxin

symptoms: rice water stools due to the presence of intestinal muscosa and epithelia cells

Heliobacter pylori

Gram negatice spiral bacteria.

produces an enzyme to break down urea to ammonia

trnansmission: person/person transfer via fecal-oral/ oral-oral route

symptoms: inflammation, stomach ulcer by compromising muscuous layer in stomach

Legionella

Gram negative rod bacteria

tranmission: inhalation of aerols from aquatic sources (ex: air conditioing towers, hot water systems, creeks, ponds)

→ resistance to chlorine treatments

symtpoms: pneumonia and respiratory failure (legionarie’s disease)

Mycobacterium

OPPORUTNISIC BACTERIA PATHOGEN

has high levels of lipid material

can cause pulmonary disease, osteoarthritis, septic arthritis

difficult to treat

Cyanobacteria

blue/green algae that produces algal blooms with foul odors and tase

→ due to geosmin and 2-methylisoborneol

can produce hepatotoxins or neurotoxins

human ingestion: headaches, gastro enteritis, muscle cramps, nasusea, pneumonia

Charactieristics of Protozoans

unicullaur

classifed according to locomotion mechanism: pseudopodia, cilia, flagella, or no locomotion

produce sexually or asexually

Giardia lablla

type of intestinal parasite and cause of waterborne disase in the US
transmission: ingestions of cysts (fecal oral route)

reservoir host: Beavers

Symptoms: loose, greasy, foul smelling stool and chronic diarrhea

Cryptosporidium

pathogentic protists that cuase cyrptoridiosis (watery diarrhea)

transmission through ingestion of sporulated oocysts from contaimed food, water, or direct conact(fecal-oral route)

Life cycle of Cryptosporidium

sporulated oocyst→ sporozoite→trophozoite→ shizont-. merozite→ gamete→ zygote→ unsporulated oocyst

Shizont

asexual stage of cryptosporidium

Entamoeba histolytica

striclty human pathogen that is respoible for the 3rd highest cause of death from parasites wordlife

→ rescoir hosts: humans, pigs, dogs, monkeys

two cyst sizes, where larger is associated with disease

Symptoms: amoebic dysntery (bloody diarrhea)

10-20microm

Size of entamoeba histolytic associated with disease

Naegleria fowleri

type of amoeboflagellate that exists as a free lviing organism found in freshwater

→ tranmission: water forcefully injected into nasal passages, follows nerves to brain

→ symptoms: primary amoebic meninogeoncephalitis(PAM) ; toxin liquifies brain and resutls ins evere massive headachef resulting in death with 4-6 days

Cyclospora

Coccidian protozoan parasite

Tranmission: Ingestion of contaimed basil, raspberries, snowpeas, or mesclun lettuce

symptoms: explosive,w atery diarrhea (cyclosporiasis)

Toxoplasma gondii

Coccidian protozoan of feline intestines

many different intermediate hosts, but oocysts only shed in feces of felines

symptons:

→ healthy individuals: flu-like symptoms

→ children and fetuses: encephalopathy, lymphadenopathy, brain damage, ocular disease

Helminths

roundworm, flatworms, tapeworm and flukes; all parasitic worm-like aniamls

multicellular and complex

Nematodes

Non segmeneted round worms

flexible outer cutcile for protection

typically lay eggs

free living in soils, fresh waters, and salt water

→ not nemerta (ribbon worms)

Ascaris lumbricoides

type of nematode that is the most common parasitic infection worldwide

tranmision: ingestion of eggs found in soils and sewage slugs

symptoms: Loeffler’s syndrome (pneumonitis), intestinial blockages in severe cases

Trichuris trichura

type of nematode pathogen

whipworm

trnamission: ingestion of eggs in contaimined water or soil

Necator americanus

type of hook worm the feeds on intestinal muscosa and blood

→ has round, cutting teeth, 7-10 mm in length

_. transmission: worm peneration of the skin in soils

symptoms: blood loss, anemia, iron deficiency

Ancylostoma dudenale

type of hookworm that feeds on intenstial mucosa and blood

→ sharp, cutting edge teeth, 10-12 mm

transmission: worm penetration of skin, typically in soils

symptoms: blood loss, anemia, iron deiciency

Taenia saginata

type of cestode

→ flt, segmentted (proglottids)

→ scolex(head)

→ suckers/and or hooks on scolex-attachment

transmission: undercooked beef containing a larval cyst

symptoms: loss of appetiite, intestinal blockage

Schistoma mansoni

flukes (trematodes)

features: bilateral symmetry, two deep suckers for attachmetn and movement

tranmission: penertation of the skin

intermdiate host: snail

Symptom: schistosomiasis; onstructive diseass, katayama fever, swimmers itch

Astrovirsues

type of virsues with icosahedral and star like shape

single stranded RNA genome

transmission: oysters

Adenovirsues

type of virsue with icosahedral shape with protruding pentons (spikes)

double-stranded DNA

symptoms: conjunctivitis (pink eye), obesity

Hepatitis A

type of virsus that affects adults more than children

• single-stranded RNA genome

symptoms: jaundice

Hepatitis E

type of virsues that is the leading cause of acute viral hepatitis found in young and middle age adults

• single stranfed RNA genome

symtpoms: jaundice

Rotavirsues

type of virsues with a two layered protein capsid

double stranded RNA genome

symptoms: watery diarrhea

Human Caliciviruses

non eneveloped viruses with single stranfed RNA genome

ex: norovirus, sapovirsues