Lecture 5 Flashcards
Gram +V and Gran -V Bacilli
Gram +ve Spore forming rods consist of…
Clostridium and Bacillus
What causes disease in spore forming rods
release of exotoxins
What is the causitvate agent of anthrax
Bacilius anthracis
What is UNIQUE about Bacilius anthracis
Its protein capsules that are antiphagocytic
Tell me about Bacilius anthracis spores
Very stable spores, resistant to heat, UV,drying, disenfectants
How are human usually exposed to Bacillus anthracis spores
through contact with animals or soil
What bacteria is used for bio-terrorism and warfare
Bacillus anthracis
What are the 3 exotoxins found in Bacillus anthracis
1) lethal factor
2)protective antigen
3)Edema factor
What does Bacillus anthracis PXO1 plasmid encode?
Bacillus anthracis exotoxins
What does Bacillus anthracis PXO2 plasmid encode?
capsule genes
What is the treatment for Bacillus anthracis?
Antibiotics: penicillin, doxycylin
Vaccine: available against Protective antigen protein
What does Bacillus cereus do?
➢Causes food poisoning when spores enter food product
What types of enterotoxins are found in Bacillus cereus
i)Heat labile: nausea, abdominal pain, diarrhea. Lasts 12-24hrs
(ii) Heat stable: SEVERE nausea and vomiting, short incubation
How is Bacillus cereus treated?
antibiotic treatment usless…resistant to penicillin
What is difference between clostridium and Bacillus
-Clostridium is anaerobic
-bacillis is aerobic
What does Clostridium botulinum do?
Neurotoxin blocks Ach release in autonomic system; flaccid
muscle paralysis:
What is the treatment for clostridium botulinum?
antitoxin and respiratory assistance
Clostridium tetani caused by?
Rusty nail contaminated with spores punctures
skin; wound provides anaerobic environment
What is the exotoxin of Clostridium tetani
tetanospasmin
What does tetnus cause the body to react?
-sustained contraction fo skeletal muscles and severe muscle spasms
Clostridium perfringens is also known as what and seen where?
Gas gangrene (seen in soldies wounded in battel)
What are the 2 classes of infection found in Clostridium perfringens
1) wounded infection: necrotic skin with “crackly” poclets
2)Clostridial myonecrosis: exotoxin secretion dystoryos muscle thus black fluid excreeted from skin
How is Clostridium perfringens treated?
treated with oxygen, antibiotics (penicillin) or amputation.
what does Clostridium difficile cause?
antibiotic-associated
pseudomembranous colitis
What is seen more commonly in hospitals than tetanus,
anthrax or botulism
Clostridium difficile
How is Clostridium difficile caused?
Overuse of broad-spectrum antibiotics destroys
normal intestinal flora
What does Clostridium difficile infect and release?
infects colon and releases exotoxins
➢Toxin A: diarrhea
➢Toxin B: cytotoxic to colon cells
What is treatment for Clostridium difficile
➢discontinue antibiotic treatment
➢Administer metronidazole or vancomycin
Clostridium difficile is treated by administration of metronidazole or vancomycin…What is different about these antibiotics ??
specifically target the bacteria responsible for the infection without affecting the entire gut microbiota as broadly as other antibiotics might
Gram +ve non spore forming rods include?
1) listeria monocytogenes
2)corynebacterium diptheriae
Where is Listeria monocytogenes found?
soft cheeses, unpasteurized milk, cold
cuts
What is the problem with Listeria monocytogenes that makes it hard to get rid of
its PSYCHROPHILE…survives in refrigerator.
What type of bacteria is Listeria monocytogenes
➢ Facultative intracellular aerobe (prefer oxygen rich environment)
What does borderes does Listeria monocytogenes cross
blood brain, GI, feto-placental
What does Corynebacterium diptheriae colonize?
Colonization of pharynx and release of exotoxins into
bloodstream
Corynebacterium diptheriae exotoxins damages what?
heart and neural cells
What is treatment of Corynebacterium diptheriae
Treatment (3 steps):
(i) Antitoxin
(ii) Penicillin or erythromycin
(iii) DPT vaccine
What are the 4 types of gram -ve Bacilli (entrics)
1)Enterobacteriaceae
2)Vibrionaceae
3)Pseudomonadaceae
4)Bacterioidaceae
Organisms are divided into groups based on??
biochemical
and antigenic properties
What is biochemical
classification?
Ability to ferment lactose
What is EMB media?
Lactose fermenters are dark purple/black
* Inhibits Gram positive bacteria
What is MacConkey Media:
- Lactose fermenters are pink-purple
- Inhibits Gram positive bacteria
list 4 other types of Biochemical
Classifications
1)H2S production
2)Hydrolysis of urea
3)Liquefy gelatin
4)Decarboxylation of amino acids
Classification Using Surface
Antigens consists of?
Variable O antigen, K-antigen, H-antigen.
What is variable O antigen?
outermost layer of LPS
common between enterics
What is K-antigen?
covers the O-antigen
What does H-antigen do?
flagellar sub-unit
* Only in motile bacteria
list the 3 scenarios of disease cause by enterics?
1) Diarrhea-with/without systemic invasion
2) Diarrhea with intestinal cell invasion
3) Diarrhea with invasion of lymph nodes and bloodstream
1) Diarrhea-with/without systemic invasion
Bacteria bind intestinal cells but do not enter
* EXOTOXIN release causes diarrhoea; ENTEROTOXIN causes fluid/electrolyte loss
* Watery diarrhoea, NO FEVER
* Vibrio cholera
2) Diarrhea with intestinal cell invasion
Bacterial virulence factors allow binding and invasion of cells
* Toxin release destroys cells bloody stools
* Fever response
* Shigella,
3) Diarrhea with invasion of lymph nodes and bloodstream
Abdominal pain with diarrhoea containing white and red cells
* Fever, headache, increased white cell counts
* Salmonella Typhi, Yersinia enterocolitica, Campylobacter jejeuni
Salmonellae is member of what family?
Enterobacteriaceae
what are the 2 types of salmonella
S. enterica and S. bongori
What are two types of s.enterica?
Enterocolitis (tummy problems) and Typhoid (enteric) fever
Complete… thier are 2 types of entercolitis S. enterica serovar
1) S. enterica serovar Enteritidis
2)S. enterica serovar Typhimurium
Complete… thier are 2 types of Typhoid S. enterica serovar
1) S. enterica serovar Typhi
2) S. enterica serovar Paratyphi
How can someone get S. enterica serovar Enteritidis aka entercolitis?
Ingestion of contaminated food
* Poultry, eggs, meat and milk
*enteric fever is?
generalized infection…bacterial
multiplication in lymphoid tissue…Necrosis of intestinal lymphoid tissue ulceration,
haemorrhage, perforation
if enteric fever is untreated what is the mortality?
10%
what term is used to refer to individuals who have recovered from an infectious disease but continue to harbor the causative microorganism within their bodies, have no symtpoms and have transmit it
Convalescent carriers:
How long is enteric fevers Convalescent carriers
3 months
chronic carriers of enteric fever?
are only 1-2% excrete bacteria for at least 6 months, sometimes life long.
What is the diagnosis for enteric fever during 1st and 2/3rd week
1st week: isolation of bacteria from blood
2-3rd week: stool and urine
Is thier treatment for enteric fever?
Vaccine available, but only effective against small bacterial
load
What is Most numerous aerobic bacteria of normal gut flora
Escherichia coli
What notable symptoms does shigellae cause?
Cause acute diarrhoea with mucus, pus and blood
Difference between shigellae sonnei and shigellae dysenteriae
Shigella sonnei Europe and North America
S. dysenteriae: tropics and severe
treatment for shigallae?
NO VACCINE
Campylobacter types?
C. jejuni and C. coli
Name the bacteria that can cause bloody diarrhea?
Shigallae and Campylobacter
Where are Pseudomonas found
mainly in moist habitats and water
what is treatment for Pseudomonas
Difficult to treat becuase ALL are ANTIBIOTIC RESISTANT
Pseudomonas aeruginosa
Respiratory pathogen in cystic fibrosis
patients AND * Infections in lesions of burn patients
What is Common contaminant of saline solutions and
water
Pseudomonas cepacia
What is Haemophilus influenzae bacteria normally apart of in the human body
nasopharyngeal flora i
What does nasopharyngeal flora cause
Meningitis, pneumonia, joint infections
What is linked to infant formula?
Cronobacter sakazakii
What is special about Helicobacter pylori
Microaerophillic and spiral bacilli
What does Helicobacter pylori cause
stomach ulcers
What does Urease do
gives protection form low pH
What is the treatment for Helicobacter pylori
triple therapy treatmnet: antibiotics and H+ pump inhibitors
What bacteria causes a CRAZY cough
Bordetella pertussis
What is prevention for Bordetella pertussis
vaccination with heat-killed organism
