Bacterial Diseases
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Transcript Bacterial Diseases
Bacterial Diseases
Gram-positive
Gram-negative
Rickettsias, Chlamydias, Spirochetes and Vibrios
Bacterial Diseases Classified by:
Airborne
Upper
Lower
Foodborne
Waterborne
Soilborne
Arthropodborne
Physical Contact
STD
Contact
Animal
Or by…..
Physiological properties:
Catalase
Hydrogen peroxide
water
Oxidase
Water
hydrogen peroxide
Peroxidase
Breakdown peroxidase (by-products that cause
tissue damage)
Or, by……..
Gram-positive
Gram-negative
Rickettsias, Chlamydias, Spirochetes and
Vibrios
Gram-positive bacteria
Staphylococcus aureus
Capsule!
grows in large, round,
opaque colonies
optimum temperature
37oC
facultative anaerobe
withstands high salt,
extremes in pH, & high
temperatures
produces many
virulence factors
Coagulase
coagulates plasma and
blood
produced by 97% of
human isolates
Hyaluronidase
promotes invasion
Staphylokinase
digests blood clots
Dnase
digests DNA
Lipases
helps bacteria colonize
oily skin
Penicillinase
inactivates penicillin
Enzymes of S. aureus
Toxins of S. aureus
hemolysins
lyse RBCs
Leukocidin
damages cell membranes
Enterotoxins
act in the gastrointestinal tract
exfoliative toxin
separates epidermal layers
toxic shock syndrome toxin (TSST)
Epidemiology and Pathogenesis
Present in most environments frequented by
humans
Readily isolated from fomites
Carriage rate for healthy adults is 20-60%
mostly in anterior nares, skin, nasopharynx, intestine
Predisposition to infection include:
poor hygiene and nutrition, tissue injury, preexisting
primary infection, diabetes, immunodeficiency
Increase in community acquired methicillin
resistance
MRSA
Staphylococcal Disease - 1
Localized cutaneous infections – invade skin through
wounds, follicles, or glands
folliculitis
superficial inflammation of hair follicle
usually resolved with no complications but can progress
furuncle
Boil
inflammation of hair follicle or sebaceous gland progresses into abscess
or pustule
carbuncle
larger and deeper lesion created by aggregation and interconnection of
a cluster of furuncles
impetigo
bubble-like swellings that can break and peel away
most common in newborns
Staphylococcal Disease - 2
Systemic infections
osteomyelitis
infection is established
in the metaphysis
abscess forms
bacteremia
primary origin is
bacteria from another
infected site or
medical devices
endocarditis possible
Staphylococcal Disease - 3
Toxigenic disease
food intoxication
ingestion of heat stable
enterotoxins
gastrointestinal distress
staphylococcal scalded skin
syndrome
toxin induces bright red flush,
blisters, then desquamation of
the epidermis
toxic shock syndrome
toxemia leading to shock and
organ failure
Other Staphylococci
S. epidermidis
lives on skin & mucous
membranes
endocarditis, bacteremia, UTI
S. hominis
lives around apocrine sweat
glands
S. capitis
live on scalp, face, external
ear
S. saprophyticus
infrequently lives on skin,
intestine, vagina; UTI
Streptococci
Gram-positive spherical/ovoid
cocci arranged in long chains
Non-spore-forming, nonmotile
Can form capsules & slime layers
Facultative anaerobes
Sensitive to drying, heat & disinfectants
25 species
Streptococci
Lancefield classification
system based on cell wall Ag
17 groups (A,B,C,….)
Another classification system
is based on hemolysis
reactions
b-hemolysis
A,B,C,G & some D strains
a –hemolysis
S. pneumoniae & others
collectively called viridans
γ-hemolysis
Enterococcus faecalis
does not induce hemolysis
Streptococci
Skin infections
Impetigo (pyoderma)
superficial lesions that break and
form highly contagious crust
often occurs in epidemics in
school children
associated with insect bites, poor
hygiene, and crowded living
conditions
Erysipelas
pathogen enters through a break in
the skin
eventually spreads to the dermis
and subcutaneous tissues
can remain superficial or become
systemic
Throat infections
Streptococcal pharyngitis
strep throat
b-hemolytic S. pyogenes
Most serious
streptococcal pathogen
Inhabits throat,
nasopharynx, occasionally
skin
Produces Ccarbohydrates, M-protein
(fimbrae), streptokinase,
hyaluronidase, DNase,
hemolysins
S. pyogenes
GAS
Produces toxins
Humans only reservoir
Transmission
contact, droplets, food, fomites
Skin infections
pyoderma, impetigo,
erysipelas
Systemic infections
strep throat, pharyngitis,
scarlet fever
S. pyogenes
Causes streptococcal
pharyngitis
Strep throat
enters the upper
respiratory tract through
respiratory droplets
Some patients with
strep throat may
develop scarlet fever
exhibiting a rash caused
by erythrogenic exotoxins
S. pyogenes
Rheumatic fever
serious complication
affecting the joints and
heart
causes permanent heart
damage called rheumatic
heart disease
Acute glomerulonephritus
rare inflammatory
response to M proteins
may lead to renal damage
Group B: S. agalactiae
Regularly resides in human vagina, pharynx &
large intestine
wound and skin infections & endocarditis in
debilitated people
can be transferred to infant during delivery &
cause severe infection
Most prevalent cause of neonatal pneumonia,
sepsis, & meningitis
Targets infants without Ab, and mothers that do not
provide passive immunity
Pregnant women should be screened & treated
“Typical” Pneumonia Can Be Caused by
Several Bacteria:
80% of “typical”
pneumonia cases are
caused by
Streptococcus
pneumoniae
Others:
Haemophilus influenzae
Staphylococcus aureus
Klebsiella pneumoniae
Streptococcus pneumoniae
Small, lancet-shaped cells
arranged in pairs and short
chains
Culture requires blood or
chocolate agar
Growth improved by 5-10%
CO2
Lack catalase &
peroxidases
cultures die in O2
S. pneumoniae
All pathogenic strains
form large capsules
major virulence factor
Vaccine available for
high risk people
S. Pneumoniae Epidemiology
5-50% of all people carry it as normal flora
in pharynx
Does not survive long outside of its habitat
Pneumonia occurs when cells are
aspirated into the lungs of susceptible
individuals
Pneumococci multiply
induce inflammatory response
Traditionally treated with penicillin G or V
Increased drug resistance
Cultivation and Diagnosis
Gram stain of specimen
presumptive identification
α hemolytic
Quellung test or capsular swelling
reaction
Bacillus
gram-positive
endospore-forming
motile rods
mostly saprobic
primary habitat is soil
versatile in degrading complex macromolecules
source of antibiotics
2 species of medical importance
Bacillus anthracis
Bacillus cereus
Bacillus anthracis
facultative
large, block shaped
rods
central spores
develop under all
conditions except in the
living body
virulence factors
capsule & exotoxins
Bacillus anthracis
3 types of anthrax
Cutaneous
spores enter through skin,
black sore
least dangerous
Pulmonary
inhalation of spores
Gastrointestinal
ingested spores
treated with penicillin or
tetracycline
http://www.youtube.com/watch?v=mi3sYzDsSGI
Bacillus cereus
common airborne &
dustborne
grows in foods, spores
survive cooking & reheating
ingestion of toxin-containing
food
causes nausea,
vomiting, abdominal
cramps & diarrhea
24 hour duration
no treatment
spores abundant in the
environment
Clostridium
gram-positive
spore-forming rods
Anaerobic
120 species
oval or spherical spores produced only under
anaerobic conditions
cause wound & tissue infections and food
intoxications
C. difficile
C. botulinum
C. perfringens
C. tetanis
Clostridium difficile-Associated Disease
(CDAD)
Normal resident of colon, in low
numbers
Causes antibiotic-associated
colitis
relatively non-invasive
treatment with broad-spectrum
antibiotics kills the other bacteria
allowing C. difficile to
overgrow
Produces enterotoxins that
damage intestines
Major cause of diarrhea in
hospitals
Increasingly more common in
community acquired diarrhea
Clostridium botulinum
Anaerobic, endospore-forming, Gram-positive
bacillus
Common in soil and water
Botulism results when the endopsores germinate
and produce botulism toxins
Clostridium botulinum
Causes 3 diseases
1. food poisoning
o
o
spores are in soil, may contaminate vegetables
improper canning does not kill spores & they germinate in
the can producing botulinum toxin
toxin causes paralysis by preventing release of
acetylcholine
2. infant botulism
o
caused by ingested spores that germinate & release toxin
3. wound botulism
o
spores enter wound & cause food poisoning symptoms
Clostridium botulinum
Diagnosis
Symptoms are diagnostic
Treatment
Administer neutralizing antibodies against
botulism toxin
Administer antimicrobial drugs in infant
botulism cases
Prevention
Proper canning of food
Infants under 1 year should not consume
honey
Clostridium perfringens
Gangrene
Mass of body tissue dies (necrosis)
Usually occurs when blood flow ceases to a
part of the body
Types :
Gas gangrene (myonecrosis)
caused when spores enter the body through a
severe open wound
Dry gangrene
Wet gangrene
Clostridium perfringens
Vegetative cells ferment
muscle carbohydrates and
decompose muscle proteins
Large amounts of gas
accumulate under the skin
causing a crackling sound
a-toxin damages and lyses
blood cells
Treatment involves:
Antibiotics
tissue debridement
Amputation
exposure in a hyperbaric
oxygen chamber
Clostridium tetani
Tetanus
Causes hyperactive muscle contractions
Spores can enter the body through a wound
produce toxins
• Tetanospasmin inhibits compounds needed to inhibit
muscle contraction
Clostridium tetani
Symptoms of tetanus include:
Trismus (lockjaw)
involves spasms of the jaw muscle and clenching of the
teeth
Opisthotonus
involves muscle spasms that cause an arching of the back
Spasmodic inhalation and seizures in the diaphragm and
rib cage
reduces ventilation
Sedatives, muscle relaxants, and penicillin are
used in treatment
Tetanus toxoid is used in vaccination
Listeria monocytogenes
non-spore-forming gram-positive
coccobacilli
1-4 flagella
no capsules
resistant to cold, heat, salt, pH extremes &
bile
primary reservoir is soil & water
can contaminate foods & grow during
refrigeration
Listeria monocytogenes
Listerosis
immunocompromised patients,
fetuses & neonates
affects brain & meninges
20% death rate
ampicillin & trimethoprimsulfamethoxazole
Prevention
pasteurization & cooking
Mycoplasmas
M. pneumoniae
primary atypical
pneumonia
Walking pneumonia
pathogen slowly spreads
over interior respiratory
surfaces
causes fever, chest pain
and sore throat
Corynbacterium diptheriae
gram-positive irregular bacilli
2 stages of disease:
1. Local infection
–upper respiratory tract inflammation
– sore throat, nausea, vomiting,
swollen lymph nodes,
pseudomembrane formation
can cause asphyxiation
2. Diptherotoxin production and
toxemia
target organs primarily heart and
nerves
Epidemiology and Pathology
Reservoir of healthy
carriers
potential for diphtheria
is always present
Most cases occur in nonimmunized children living
in crowded, unsanitary
conditions
Acquired via respiratory
droplets from carriers or
actively infected
individuals
Corynbacterium diptheriae
Diagnostic methods
Pseudomembrane and swelling indicative
Stains
Conditions, history
Serological assay
Treatment:
Antitoxin
Penicillin or erythromycin
Prevented by toxoid vaccine series and
boosters
Mycobacterium Genus
gram-positive irregular bacilli
acid-fast staining
strict aerobes
produce catalase
possess mycolic acids & a unique type of
peptidoglycan
do not form capsules, flagella or spores
grow slowly
2 medically important:
Mycobacterium tuberculosis
Mycobacterium leprae
Mycobacterium tuberculosis
contain complex waxes
& cord factor
prevent destruction by
lysosomes of
macrophages
transmitted by airborne
respiratory droplets
only 5% infected people
develop clinical disease
Primary TB
infectious dose 10 cells
phagocytosed by
alveolar macrophages
multiply intracellularly
after 3-4 weeks
immune system
attacks, forming
tubercles
granulomas consisting
of a central core
containing bacilli
surrounded by WBCs
Secondary TB
reactivation of bacilli
tubercles expand & drain into the bronchial
tubes & upper respiratory tract
gradually patient experiences more severe
symptoms
violent coughing, greenish or bloody sputum,
fever, anorexia, weight loss, fatigue
untreated 60% mortality rate
Extrapulmonary TB
during secondary TB, bacilli disseminate
to regional lymph nodes, kidneys, long
bones, genital tract, brain, meninges
these complications are grave
Diagnosis
1. in vivo or tuberculin
testing
2. X rays
3. direct identification
of acid-fast bacilli in
specimen
4. cultural isolation
and biochemical
testing
Treatment of TB
6-24 months of at least 2 drugs from a list
of 11
one pill regimen called Rifater (isoniazid,
rifampin, pyrazinamide)
vaccine based on attenuated bacilli
Calmet-Guerin strain of M. bovis used in
other countries
Mycobacterium leprae
Hansen’s bacillus
strict parasite
slowest growing of all species
multiplies within host cells in large packets called
globi
causes leprosy
chronic disease that begins in the skin & mucous
membranes & progresses into nerves
Leprosy (Hansen’s Disease)
spread through direct inoculation
from leprotics
2 forms
tuberculoid
superficial infection without skin
disfigurement
damages nerves and causes loss of
pain perception
lepromatous
deeply nodular infection
causes severe disfigurement of the
face & extremities
Diagnosing
Combination of
symptomology,
microscopic
examination of
lesions, and patient
history
Detection of acid-fast
bacilli in skin lesions,
nasal discharges,
and tissue samples
Treatment and Prevention
Treatment by longterm combined
therapy
Prevention requires
constant surveillance
of high risk
populations
WHO sponsoring a
trial vaccine
Gram-negative Cocci and Bacilli
Bacterial Meningitis
meninges of brain and
spinal cord
cross the blood-brain
barrier
can be caused by
several bacterial
species
Neisseria meningitides
Streptococcus
pneumoniae
Haemophilus influenzae
Neisseria
Gram-negative diplococci
none develop flagella or spores
capsules on pathogens
Strict parasites
do not survive long outside of the host
Residents of mucous membranes of warm-blooded
animals
Aerobic or microaerophilic
Pathogenic species require enriched complex media and
CO2
2 primary human pathogens
Neisseria gonorrhoeae
Neisseria meningitidis
Neisseria meningitidis
Virulence factors
capsule, pili, IgA protease
12 strains
serotypes A, B, C, cause most cases
Disease begins when bacteria enter bloodstream,
pass into cranial circulation, multiply in meninges
very rapid onset
endotoxin causes hemorrhage and shock
can be fatal
Treated with penicillin, chloramphenicol
Vaccines exist for group A and C
Neisseria gonorrhoeae
Causes gonorrhea
Virulence factors
pili, other surface molecules, IgA protease
Strictly a human infection
In top 5 STDs
Infectious dose 100-1,000
Does not survive more than 1-2 hours on
fomites
Infection is asymptomatic in 10% of males and
50% of females
Gonorrhea
Males
urethritis, yellowish
discharge, scarring &
infertility
Extragenital infections
anal, pharygeal,
conjunctivitis,
septicemia, arthritis
Gonorrhea
Females
vaginitis, urethritis,
salpingitis (PID) mixed
anaerobic abdominal
infection
common cause of
sterility & ectopic tubal
pregnancies
Gonorrhea in Newborns
Infected as they pass
through birth canal
Eye inflammation,
blindness
Prevented by
prophylaxis after birth
Diagnosis and Control
Gram stain
20-30% of new cases
are penicillinaseproducing PPNG or
tetracycline resistant
TRNG
Recurrent infections
can occur
Reportable infectious
disease
Enterobacteriaceae Family
Enterics
gram-negative bacteria
many members inhabit soil,
water, & decaying matter
cause diarrhea through
enterotoxins
divided into coliforms (lactose
fermenters) and non-coliforms
(non lactose fermenters)
Antigens and virulence factors of
typical enteric bacteria
Testing of Enterics
miniaturized, multichambered tube
inoculating rod pulled through length of tube
carries an inoculum to all chambers
Coliform Organisms and Diseases:
Escherichia coli
most common aerobic & non-fastidious
bacterium in gut
@ 150 strains
Most not infectious
Escherichia coli
enterotoxigenic E. coli
causes severe diarrhea due to heat-labile
heat-stable toxin
stimulate secretion & fluid loss
also has fimbrae
toxin &
enteroinvasive E. coli
causes inflammatory disease of the large intestine
enteropathogenic E. coli
linked to wasting from infantile diarrhea
Enterohemorrhagic E. coli
Newest strain
Can permanently damage kidney
Escherichia coli
pathogenic strains frequent agents of
infantile diarrhea
greatest cause of mortality among babies
causes ~70% of traveler’s diarrhea
causes 50-80% UTI
indicator of fecal contamination in water
Other Coliforms
Serratia marcescens
produces a red pigment
causes pneumonia,
burn & wound
infections, septicemia &
meningitis
Klebsiella
pneumoniae
Citrobacter
opportunistic UTIs &
bacteremia
Salmonella
S. enteritidis
1,700 serotypes
salmonellosis
zoonotic
gastroenteritis 2-5 days
Typhoid Fever
caused by Salmonella enterica
serotype Typhi
(S. typhi)
typhoid fever
ingested bacilli adhere to small
intestine
cause invasive diarrhea that leads
to septicemia
S. Typhi is transmitted by the
five Fs:
Flies
Food
Fingers
Feces
Fomites
Shigella
shigellosis
incapacitating dysentery
S. dysenteriae, S. sonnei,
S. flexneri & S. boydii
produce H2S or urease
Nonmotile
nonencapsulated
Shigella
invades villus of large intestine
can perforate intestine or invade blood
enters Peyer’s patches & instigates inflammatory
response
endotoxin & exotoxins
treatment
fluid replacement & ciprofloxacin & sulfa-trimethoprim
Yersinia pestis
tiny, gram-negative rod
unusual bipolar staining & capsules
virulence factors
capsular & envelope proteins protect against
phagocytosis & foster intracellular growth
coagulase
Yersinia pestis
sylvatic plague
humans develop plague through contact with wild
animals
urban plague
domestic or semidomestic animals or infected humans
found in 200 species of mammals
rodents harbor the organism but do not develop the
disease
flea vectors
bacteria replicates in gut, coagulase causes blood
clotting that blocks the esophagus
flea becomes ravenous
Pathology of Plague
bubonic
bacillus multiplies in flea bite, enters
lymph, causes necrosis & swelling in
groin or axilla
bubo
septicemic
progression to massive bacterial growth
virulence factors cause intravascular
coagulation subcutaneous hemorrhage
& purpura
black plague
pneumonic
infection localized to lungs, highly
contagious
fatal without treatment
Plague
Treatment
streptomycin,
tetracycline or
chloramphenicol
Killed or attenuated
vaccine
http://www.youtube.com/watch?v=9IjhQDnoCcY
Bordetella pertussis
aerobic coccobacillus
causes pertussis or whooping cough
communicable childhood affliction
acute respiratory syndrome
often severe, life-threatening complications in
babies
reservoir
apparently healthy carriers
transmission by direct contact or inhalation of
aerosols
Bordetella pertussis
virulence factors
receptors that recognize & bind to ciliated
respiratory epithelial cells
toxins that destroy & dislodge ciliated cells
DTaP vaccine
acellular vaccine contains toxoid & other Ags
Pseudomonas
small gram-negative bacilli
single polar flagellum
highly versatile metabolism
Pseudomonas aeruginosa
intestinal resident in 10% normal people
resistant to soaps, dyes, quaternary
ammonium disinfectants, drugs, drying
Use aerobic respiration
do not ferment carbohydrates
Opportunistic
Pseudomonas aeruginosa
common cause of nosocomial infections in hosts
with burns, neoplastic disease, cystic fibrosis
complications include pneumonia, UTI,
abscesses, otitis, & corneal disease
grapelike odor
greenish-blue pigment (pyocyanin)
multidrug resistant
Francisella tularensis
causes tularemia
zoonotic disease of mammals (particularly rabbits)
endemic to the northern hemisphere
Aerobic bacilli
transmitted by contact with infected animals,
water & dust or bites by vectors
headache, backache, fever, chills, malaise &
weakness
intracellular persistence can lead to relapse
30% death rate in systemic & pulmonic forms
gentamicin or tetracycline
“Atypical” Pneumonia Can Be Caused by
a Diverse Group of Bacterial Species
Mycoplasma pneumoniae
Legionella pneumophila
Coxiella burnetii
Chlamydia pneumoniae
Chlamydia psittaci
Legionella pneumophila
“Legionellosis”, Legionaires
disease
Motile aerobic bacilli
widely distributed in water
live in close association with
amebas
prevalent in males over 50
nosocomial disease in elderly
patients
fever, cough, diarrhea,
abdominal pain, pneumonia
fatality rate of 3-30%
azithromycin
Rickettsias, Chlamydias,
Spirochetes and Vibrios
Rickettsia
obligate intracellular parasites
gram-negative cell wall
among the smallest bacteria
nonmotile pleomorphic rods or coccobacilli
ticks, fleas & louse are involved in their life cycle
bacteria enter endothelial cells & cause necrosis
of the vascular lining
treat with tetracycline & chloramphenicol
4 Types of Rickettsioses
Rocky Mountain spotted fever
R. rickettsii
zoonosis carried by dog ticks & wood ticks
most cases on eastern seaboard
distinct spotted rash
Chlamydias
obligate intracellular
parasites
small gram-negative
cell wall
alternate between 2
stages
elementary body
small metabolically
inactive, extracellular,
infectious form
reticulate body
grows within host cell
vacuoles
Chlamydia trachomatis
1. trachoma
attacks the mucous membranes of the
eyes, genitourinary tract & lungs
ocular trachoma
• severe infection, deforms eyelid &
cornea, may cause blindness
inclusion conjunctivitis
• occurs as babies pass through birth
canal
• prevented by prophylaxis
2. STD
urethritis, cervicitis, scarring
lymphogranuloma venereum
disfiguring disease of the external
genitalia & pelvic lymphatics
Spreading to the fallopian
tubes can cause salpingitis
Left untreated can cause
pelvic inflammatory disease
(PID)
Increases the danger of
infertility or ectopic
pregnancies
Chlamydia can also occur in
the pharynx or anus
Males complain of painful
urination and watery discharge
cause infertility in males
Spirochettes
Treponema
Borrelia
Treponema
Gram-negative spirochetes
live in the oral cavity, intestinal tract, &
perigenital regions of humans & animals
pathogens are strict parasites
Treponema pallidum
human is the natural host
extremely fastidious &
sensitive
cannot survive long outside
of the host
causes syphilis
ID = 50 cells
Pathogenesis and Host Response
Spirochete binds to epithelium, multiplies, and
penetrates capillaries.
Moves into circulation and multiplies
Untreated marked by stages
Primary
Secondary
Tertiary
Spirochete appears in lesions and blood during
first 2 stages
communicable
Stages of Syphilis
Primary syphilis
appearance of hard
chancre at site of
inoculation
chancre heals
spontaneously
Secondary syphilis
fever, headache, sore
throat, red or brown rash
on skin, palms and soles
rash disappears
spontaneously
Stages of Syphilis
Tertiary syphilis
about 30% of infections enter
in tertiary stage
can last for 20 years or longer
neural, cardiovascular
symptoms, gummas develop
Congenital syphilis
nasal discharge, skin
eruptions, bone deformation,
nervous system abnormalities
Borrelia
Borrelioses
Gram-negative spirochetes
transmitted by arthropod vector
B. hermsii
relapsing fever
B. burgdorferi
Lyme disease
B. hermsii - Relapsing Fever
mammalian reservoirs
squirrels, chipmunks, wild rodents
tick-borne
after 2-15-day incubation, patients have high
fever, shaking, chills, headache, & fatigue
Nausea, vomiting, muscle aches, abdominal
pain
extensive damage to liver, spleen, heart, kidneys, &
cranial nerves
parasite changes & immune system tries to
control it
recurrent relapses
tetracycline
B. burgdorferi - Lyme Disease
transmitted by ticks
complex 2-year cycle
involving mice & deer
nonfatal, slowly
progressive syndrome
that mimics
neuromuscular &
rheumatoid conditions
B. burgdorferi - Lyme Disease
Symptoms:
70% get bull’s eye rash
fever, headache, stiff
neck, & dizziness
if untreated can progress to
cardiac & neurological
symptoms, polyarthritis
tetracycline, amoxicillin
vaccine for dogs, human
vaccine discontinued
insect repellant containing
DEET
Vibrio cholera
Cholera
Curviform gramnegative
top 7 causes of
morbidity & mortality
ingested with food or
water
infectious dose 108
Vibrio cholera
infects surface of small intestine,
noninvasive
cholera toxin causes electrolyte & water
loss through:
secretory diarrhea, resulting dehydration leads
to muscle, circulatory, & neurological symptoms
Treatment
oral rehydration, tetracycline
vaccine
Campylobacter jejuni
important cause of bacterial
gastroenteritis
transmitted by beverages &
food
Curviform gram-negative
reach mucosa at the last
segment of small intestine
near colon
adhere, burrow through
mucus and multiply
symptoms of headache,
fever, abdominal pain,
bloody or watery diarrhea
Helicobacter pylori
Curviform gram-negative
discovered in 1979 in stomach biopsied
specimens
causes 90% of stomach & duodenal ulcers
people with type O blood have a 1.5-2X
higher rate of ulcers
Same receptor in common
produces large amounts of urease
© P. Hawtin/Photo Researchers, Inc.
The bacteria produce
urease, which in turn
produces ammonia
neutralizes acid in
that area of the
stomach
allows the
bacteria to survive
The ammonia, and
an H. pylori cytotoxin
destroy mucoussecreting cells
creates a sore