Bacilli Flashcards
What’s a spore?
Released by certain bacteria when it sense it’s in danger.
Gives it the ability to survive in different environment.
Metabolically inactive.
when it senses it’s safe: comes out of vegetative state and release potent exotoxins = diseases
Name (6) spore forming gram + bacilli
Bacillus anthracis Bacillus cereus Clostridium botulinum Clostridium tetani Clostridium perfringens Clostridium difficile
Bacillys anthracis characteristics (5)
Unique protein capsule (antiphagotic)
Aerobic
Spores very stable to heat, drying, UV and disinfectants
Used in bio-terrorism and warfare
Bacillus anthracis exotoxins
Encoded on pXO1 plasmid: optimally increased @37C, increased CO2 (respiratory tract)
pXO2 plasmid encodes genes: both plasmid necessary for virulence
3 seperate proteins: edema factor (EF), protective antigen (PA) lethal factor (LF): separate are not toxic but together yes
Bacillus anthracis: disease
Anthrax
B. anthracis treatment
Antibiotics (penicillin)
Vaccine available for Protective antigen (PA) protein
B. cereus characteristics (2)
Motile
non encapsulated
B. cereus: disease (2 types of enterotoxins)
causes food poisoning with enterotoxins
heat labile: nausea, abdominal pain, diarrhea (12-24h)
heat stable: severe N/V (short incubation)
B. cereus treatment
penecillin resistant (antibiotic treatment are useless)
C. botulinum characteristics (2)
found in smoked fish or improperly canned vegetables
botox: paralyse to get rid of wrinkles or excessive sweating
C. botulinum (disease) (2)
rapid fatal food poisoning: lethal neurotoxin blocks Ach release in autonomis system: flaccid muscle paralysis
afebrile, bilateral cranial nerve palsies, double vision, trouble swallowing, muscle weakness, deadly if gets to respiratory tract
infant botulism (honey): spores germinates and bacteria colonize colon: constipation, trouble swallowing muscle weakness
C. botulinum treatment
antitoxin and respiratory assistance if needed
C. tetani disease
tetanus (rusty nail contaminated with spores)
exotoxin: tetanospasmin
substained severe contraction of skeletal muscles
severe muscle spasms (lock jaw) high mortality rate (heart stays contracted)
C. tetani (treatment)
Booster (inactivated toxoid) every 10 years
C. perfringens disease (2 classes)
gas gangrene:
- wound infection/cellulitis: necrotic skin exposed to bacteria, damage to local tissue (skin moist, spongy with crackly pockets)
- clostridial myonecrosis: bacteria inoculated into muscle, exotoxin secretion destroys adjacent muscles (when degrade: black fluid excreted from skin) (fatal if not treated)
C. perfringens treatment (clostridial myonecrosis)
oxygen
antibiotics (penicillin)
removal of damaged tissue
C. difficile characteristics (2)
- more common in hospitals than tetanus, anthrax or botulism
- overuse of broad-spectrum antibiotics destroys normal intestinal flora (get it once, more chance of getting it again)
C. difficile disease
Antibiotic-associated pseudomembranous colitis
infected colon release toxin:
toxin A: diarrhea
toxin B: cytotoxic to colon cells
severe diarrhea, abdominal cramping, fever
C. difficile treatment
discontinue antibiotic treatment to allow normal flora back
administer metronidazole or vancomycin
Clostridium bacterias characteristics
anaerobics (different from bacillus) powerful exotoxins (rapid diagnosis possible)
Non spore forming rods (2)
Listeria monocytogenes
Corynebacterium diphteriae
L. monocytogenes charateristics (4)
- food: soft cheese, unpasteurized milk, cold cuts, pâté
- psychrophile (survives in refrigerator)
- facultative intracellular aerobe
- can pass 3 protective barriers (blood-brain, GI, feto-placental)
L. monocytogenes disease
listeriosis: general malaise, diarrhea, meningitis, speticeamia, still-birth/abortion
high mortality rate
L. monocytogenes treatment
antibiotics
no vaccines
C. diphteriae disease
diphteria: colonization of pharynx and release in the blood stream
exotoxins damages heart and neural cells
C. diphteria treatment
antitoxin, penicillin, DTP vaccine
can be lysogenized by bacteriophage
4 groups of enteric gram - bacilli
Enterobacteriaceae: salmonella, shigella, E. coli
Vibrionaceae: Vibro, campylobacter
Pseudemonadaceae: pseudonomas
Bacteriaidaceae
Classification of enterics
Biochemical classification (nutritional needs) lactose fermentation (EMB: dark purple/black, MacConkey: pink)
surface antigen
variable O antigen (outermost layer of LPS): changes between enteric
K-antigen: covers the O-antigen
H-antigen: flagellar sub-unit (only in motile bacteria)
Diseases caused by enterics (4 categories)
- diarrhea with/without systemic invasion
binds to intestinal cell but do not enter
exotoxin release: diarrhea, enterotoxin: fluid/electrolyte loss
watery diarrhea, no fever
vibrio cholera - diarrrhea with intestinal cell invasion
binding and invasion of cells
bloody stools, fever response
shigella - diarrhea with invasion of lymph nodes and bloodstream
AP, diarrhea containing white and red blood cells, fever headache, increased white and red blood cell counts
salmonella typhi, Yersinia enterocolitica, campylobacter jejeuni - other enterics intecions
UTI, pneumonie, bacteremia, sepsis
nosocomial infections by E. coli, etc.
Salmonellea characteristics (3)
enterobacteriaceae
unable to ferment lactose
all in animal reservoirs except S. enterice serovar typhi (human host only)
Salmonellea type (5) + characteristics
- S. enterica
serovar enteritidis: enterocolitis, min 10^5, incubation time 6-48h, contamined food (poultry, eggs, meat) or person to person
Typhymurium: human host
Typhi: typhoid fever, contaminated products (milk, milk product, contaminated water, shellfish, food handling
Paratyphi: parathyphoid fever (milder)
S. bongori
Salmonella diseases
enterocolitis: N/V, profus diarrhea, AP, fever, chills, headach, myalgia (2-3 recovery), speticemia (rare)
enteric fever: generalized infection (bacterial multiplication in lymphoid nodes), necrosis of intestinal tissue (ulcer, hemorrhage, perforation)
Salmonella treatment/diagnosis
use stool for culture diagnosis (isolation from blood 1st week, or urine/stool 2-3rd weeks)
vaccine available but only effective on small bacteria load
antibiotic not recommended (kill normal flora)
E. coli characteristics (3)
most numerous aerobic bacteria of normal gut flora
lactose fermenting
pathogenic to other parts of the body (opportunistic)
Diseases E coli
Bacteriuria
Gastroenteritis
neonate meningitis and nosocomial urinary and wound infection
E coli gastroenteritis types (4)
Enterotoxigenic E coli: infant diarrhea, traveller’s diarrhea, enterotoxins
Enteroinvasice E. coli: similar to shigellosis
Enteropathogenic E. coli: older name for serotypes causing infant diarrhea
E. coli O157: H7: haemorrhagic colitis, hamburger disease
Shigellae characteristic, prevention, treatment
non-lactose fermenter
seen in children, poor sanitation and crowding
prevention: safe food handling, clean water, safe disposal of sewage
no vaccine
Shigellae disease
acute diarrhea with mucus, pus and blood
shigella sonnei (europe and north america)
S. dysenteriae: tropics, severe illness (watery diarrhea, cramps, fevers) infection from small number of organisms
vibrio cholerae characteristics and disease
South-east asia, Africa
mainly water-borne
cholera: GI illness: profuse water diarrhea, cramps, fever
enterotoxin binds to cells intestin: cells secrete chloride, absorb less Na: water accumulates in intestine= watery diarrhea (10-15 L/day) = dehydration
Campylobacter (2 types, disease)
C. jejuni C. coli
Normal flora of birds and domestic animals
some strains invasive, some toxigenic
causes human enteritis (number one cause of gastroentritis): fever, AP, bloody diarrhea
maybe on cause of traveller’s diarrhea
Pseudonomas (general + 2 types)
General: opportunisitic pathogen, found in moist habitat and water (eg: humidifiers), resistant to many antibiotics
P. aeruginosa: respiratory pathogen in CF patients, infection in lesions of burn patients
P. cepacia: common contaminant of saline solution and water, able to multiply in low nutrient environments: respiratory pathogen in CF patient
Haemophilus influenzae
part of normal nasopharyngeal flora in many adults and children
invasive infection of young children (meningitis, pneumonia, joint infections)
increased bronchial inflammation in pts already having chronic bronchitis
vaccine available
Enterobacter spp.
nosocomial infection, wound infection, pneumonia, bacteremia
E. sakazakii linked to infant illness from powdered infant formula
H. pylori
microaerophilic, spiral bacilli
urease: protection from low pH
causes stomach ulcers
triple therapy treatment: antibiotics and H+ pump inhibitors
Bordetella pertussis (4 virulence factors)
- pertussis toxin
- extra cyytoplasmic adenylate cyclase (weakens host defense)
- filamentous hemagglutinin: bronchial attachment and release
- tracheal cytotoxin: destroys ciliated cells: poor clearance of mucus and bacteria
whooping cough
vaccine with heat killed organisms
Legionella pneumophila
opportunistic pathogen
grows in water, shower head
transmission: aerosols
causes legionnaires disease
may cause severe pneumonia
