Midterm II Flashcards
Bacillus anthracis
- G+ bacilli
- Potent Exotoxin Anthrax
- Spore forming
- UNIQUE protein capsule, antiphagocytic
- Aerobic
- Sporulating (resistant heat, dryness, UV light)
- RAPID Treatment with penicillin, ciproflaxin
Bacillus anthrasis Exotoxin
-pXO1 plasmid
-optimally transcribed at 37C, increased CO2 and serum proteins
3 proteins:
-Edema factor (EF)
-Protective antigen (PA)
-Lethal Facor (LF)
- Toxic when combined
- pXO2 plasmids required for virulence
Bacillus cereus
- G+ bacilli
- Spores cause food poisoning
- motile
- Enterotoxin responsible:
1) Heat labile: nausea, ab pain, 12-24 hr diarhea
2) Heat stable: SEVERE nausea and vomiting
RESISTANT
Clostridium botulinum
- G+ bacilli
- Anaerobic
- spore forming
- Fatal
- Neurotoxin blocks Ach release (flaccid muscle paralysis)
- Afebrile, nerve palsies, weakness
Treatment
antitoxin and respiratory assistance
-Infant botulism
Clostridium tetani
-G+ bacilli
-Spore forming
-Exotoxin: tetanospasm
(muscle spasms, Lock-Jaw)
-Boosters
Clostridium perfringes
-G+ bacilli
-Spore Forming
-‘gas gangrene’
2 types of infection
1) wound infection/ cellulitis (necrotic skin, damage to local tissues, spongy)
2) clostridial myonecrosis (trauma into muscles, black fluid FATAL)
Treatment
Oxygn to exposed area, penicillin
Clostridium difficile
-G+ bacilli
-Spore forming
-antiobiotic associated pseudomembranous colitis.
-over perscription of broad spectrum ab (hospitals)
Toxin A: diarrhea
Toxin B: cytotoxic to colon cells
Treatment: Live probiotics (vancomycin) low oral bioavailability
Listeria monocytogenes
- G+
- NON spore forming
- Faculative intracellular aerobe
- Listeriosis
- psychrophile, will live in the fridge
- meningitis, septicemia
- crosses blood brain,GI and feto-placental
Corynebacterium diptheriae
-G+
-NON spore forming
-Damages Heart and Neurons
Treatment:
-Antitoxin
-Penicillin
-DPT vaccine
EMB/ MacConkey Media
- Selective/ differential media
- Inhibition of Gram + bacterial growth
- Lactose fermenters colorize.
Biochemical Classifications (G- bacilli)
- H2S Production
- Hyrdolysis of Urea
- Liquefy gelatin
- Decarboxylation od amino acids
Classification of surface antigens (G- bacilli)
Variable O-antigen: outermost layer of LPS
K-antigen: covers the O antigen
H-antigen: flagellar sub unit, only in motile bacteria
Diarrhea-with/without systemic invasion
- bind intestinal cells but do not enter
- Exotoxin release causes diarrhoea
- Enterotoxin release causes fluid/ electrolyte loss
- watery, no fever\
- ‘Vibrio cholera’
Diarrhea with Intestinal cell invasion
- Virulence factors allow binding and invasion of cells
- Toxin release destroys cells BLOODY POOPS
- FEVER
- ‘shigella’
Diarrhea with invasion of lymph nodes and bloodstream
- ab pain
- Fever, Headache, increase white cell counts
- ‘Salmonella typhi, Yersinia enterocolitica, Campylobacter jejeuni’
Salmonella enterica serovar Enteritidis
- G- baccili
- Enterocolitis (fever, chills, headache myalgia)
- 2-3 days recovery
- you need to ingest 10^5
- 6-48h incubation
From where?
- person to person
- underreported
Salmonella enterica serovar Typhimurium
-G- bacilli
-Enteric fever and Enterocollitis
“Typhoid Fever”
-bacterial multiplication in lymphoid tissue
-ulceration, haemorrhage, perforation
-convalescent carriers excrete bacteria for 3 months
Salmonella enterica serovar paratyphoid
same as typhoid
Escherichia coli
-G- bacilli
-Lactose fermenting
-aerobic
-normal gut flora
ENTEROTOXIGENIC Ecoli: infant diarrhoea, Traveller’s diarrhoea, Enterotoxins
ENTEROINVASIVE Ecoli: like shigellosis
E.coli O157:H7
- Haemorrhagic colitis
- Hamburger Disease
- proper food handling
Shigellae
- G- Bacilli
- Non lactose fermenting
- diarrhoea with mucus, pus and blood
S. dysenterae
- tropics
- Severe illness: Watery diarrhoea, cramps, fever.
- children, poor sanitation, crowding,
- No Vaccine
Vibrio Cholerera
- G- bacilli
- Enterotoxin binds cells in small intestine
- Cells secrete chlorides, lower Na+ absorption
- WATERY diarrhea
- Severe dehydration and death (10-15 L water loss)
- Common in Africa
Campylobacter
-G- bacilli
-Jejuni and coli
-major cause of human enteritis
-normal flora in birds and domestic animals
SYMPTOMS
-fever, ab pain, bloody diarrhoea
-Maybe travellers diarrhea??
Pseudomonas aeruginosa
-G- bacilli
-moist habitat
-many resistant strains
-Respiratory pathogen in cystic fibrosis
-
Pseudomonas cepacia
- Common in saline solutions
- able to multiple in low nutrient environment
- Respiratory pathogen of cystic fibrosis patients
Haemophilus influenzae
- G- bacilli
- Normal noropharyngeal flora in many adults and children
- meningitis, pneumonia, joint infections
- vaccine
Enterobacter spp.
- G- bacilli
- wound infections, pneumonia, bacteremia
- powdered infant formula
Heliobacter pylori
-G- rods
-spiral bacilli
-stomach ulcers
-Dr. Robert Warren and Dr. Barry Marshall
-Urease secreation to protect from low pH
THERAPY
-Proton pump inhibitors +antibiotics
Bordetella pertussis
-G- bacilli Whooping Cough 4 virulence factors 1) Perussis toxin (A-B) 2) Extra cytoplasmic adenylate cyclase 3) filamentous hemagglutinin 4) Tracheal cytotoxin (destroy ciliated cells)
-vaccination
Legionella pneumophila
- G- bacilli
- Opportunistic
- water, shower heads, air cooling
- Exposure to aerosol and NO person
Mycobactreria General
- cause tuberculosis and leprosy
- Waxy NO GRAM STAIN
- disinfectant resistance
- Ziehl-Neelsen staining
Ziehl-Neelsen Staining
STAINING OF MYCOBACTERIA
1) Ziehl-Neelesen carbol fuchsin to the slide for five minutes while applying heat
2) Gentle wash with water to cool the slide
3) Acid alcohol added to decolorize
4) Wash slide again with water and counterstain with methylene blue for 1- minutes
Mycobacterium tuberculosis
-Chronic, Slow, pulmonary infection
-aerosol droplet transmission
-Obligate aerobe, faculative intracellular parasite
-4-6 weeks see colonies on plate(Lowestein-Jensen Medium)
PRIMARY TB
1) aerosol Inhilation
2)Bacterial multiplication in alveoli
3)Macrophage ingestion of bacilli and formation of primary complex
4) Foci of infection in lungs, spread t kidneys, bones meninges possible)
5) CMI is fully active, infection is stopped
6) some bacilli survive, reactivation many years later
POST PRIMARY
- Late reactivation in lungs
- chronic infection
TB immunity
Mantoux test -Tuberculin solution injection intradermally >10mm positive 5-9 mm Doubtful <4mm negative
Atypical Mycobacterium
- Seen in Immune compromised individuals
- M. kansassi, M. avium, M intracellulare
- These give a doubtful mantoux test
M. marinum: skin infection
M. fortuitum: soft tissue abscessess
Mycobacterium Leprae (2 Types)
TUBERCULOID LEPROSY
-visible nerve enlargement, few erythmatous plaques, low bacteria but high lymphocytes and granulomas
LEPROMATOUS LEPROSY
- No nerve enlargement
- many erythmatous nodules, high bacilli, high infectivity
Treponema pallaidum
-G- Spirochyte
-Syphilis
-unculturable in vivo
Stages
1) Use dark field microscopy, maybe Ziehl-Neelsen
-bacteria in fluid from lesions
2) 6 weeks after appearance of chancre
- generalized mucosal rash
- Lessions with many treponemes (Bact)
3) Latent
- No symptims of infection
- Non-transmittable
4) Late syphilis
- Obliterative endarteritis
- skin, mucosae, Nervous, Cardio
VDRL
- non-treponemal test
- nonspecific use of cardiolipin
- early stage
Treponemal tests
-FTA-ABS flourescent Treponemal Antibody Absorption
Borrelia burgdorferi
- G- spirochyte
- Lyme Disease
- skin, joints, nervous system, heart
- Serology for diagnostics
TREATMENT
-Doxycycline, amoxicillin,
PREVENTION
- avoid ticks
- vaccine available: ospA antigen or organism
Chlamydia trachomatis
-Obligate intracellular parasites; cocci
-Can’t make their own ATP
-Can not be grown on artificial media
2 LIFE FORMS
1) elementary body, infectious form (300-400 nm)
2) Reticulate body, growth form (800-1000 nm)
-most common STD in canada and US
- asymptomatic untreated
- urethritis/ cervicitis
Trachoma
- Chlamydia trachomatis
- chronic occular infection
- leading cause of blindness in Middle East, North Africa, South east Asia
Lymphogranuloma venereum
- Chlamydia trachomatis
- endemic in tropical and subtropical countries
Chlamydia pneumoniae
- Respiratory tract infection, mild pneumonia
- Usually subclinical
Chlamydia psittaci
- Bird pathogen
- Transmission to humans
- Pneumonia or endocarditis
Mycoplasma General
- Smallest free living bacteria (100-300 nm)
- Saphrophytes, part of normal flora of the oropharynx and Genital tract of humans
- No true cell wall
Mycoplasma pneumoniae
- Primary caus eof atypical pneumonia
- Diagnosis is clinical, no lab confirmation
TREATMENT
-erthyromycin or tetracycline
Levels of fungal infections
1) superficial
2) Cutaneous
3) Subcutaneous
4) Systemic
Cryptococcosis
- Fungal infection
- Systemic
- casues tumours in lungs, can spread to the brain (meninges)
- defining oppertunistic infection of immunocompromised individuals
Aspergillus
- Fungus
- People with compromised immune systems are susceptible.
- Secretes aflatoxin which is carcinogenic
