Finals Flashcards
If cholera not promptly treated leads to
Dehydration, acidosis, hypokalemia, shock and death
Cholera characterised by
Voluminous watery stool, vomiting, hypovolemic shock and acidosis
Mode of transmission of cholera
Fecal-oral route
Source of infection of cholera
Human (primarily) and marine shellfish
Potent cholera enterotoxin is
Choleragen
Cholera is :
- Pandemic
- Epidemic
- Endemic
Epidemic
Important risk factor for gastric carcinoma and lymphoma
H.pylori ( helicobacter pylori )
Mode of transmission of h.pylori
Oral-oral or faecal-oral route
Source and reservoir of H.pylori
Human only
The ammonia produced also neutralizes gastric acidity allowing the organism to
survive causing persistent colonization which may lead to
Chronic gastritis, gastric atrophy and gastric carcinoma.
Gram -ve bacilli related to intestinal tract
Vibrio and helicobacter
Gram -ve bacilli related to respiratory tract
Heamophilus
Bordetella and
Legionella
Members of this genus is gram -ve coccobacilli
Heamophilus
1- ……. Major pathogen in haemophilus
2-……. Normal flora of the mouth and upper respiratory tract causes pneumonia or endocarditis
3-………. Causes chanroid (soft sore) —-> sexually transmitted disease manifested as an ulcer on the external genitalia
1- H.influenza
2- H.parainfluenza
3- H.ducreyi
The most virulent organism in H.influenza?
Type b
Mode of transmission of capsulated (typable) H.influenza
Droplet infection
Non-capsulated H.influenza causes non-invasive diseases such as
Otitis media, sinusitis and bronchitis
Most common cause of meningitis in children (less than 5y)
H.influenza type b
H.influenza type b cause invasive infection which are usually bacteraemic such as:
Meningitis, pneumonia & empyema (mainly in adult), acute epiglottis ( mainly in children), cellulitis, infective arthritis.
Carboxyphilic ( facultative anaerobic & required 5-10 co2)
H.influenza
G.r / H.influenza grows on chocolate agar but not on blood agar
Because is Heamophilic, requires both factors x&v
Most important member of the genus Bordetella
Bordetella pertussis
The media can be used for isolation of B.pertussis
Bordet-Gengou medium
And charcoal-blood agar
Mode of transmission for pertussis
Droplet infection
Whooping cough (pertussis) characterised by
Paroxysms (attack) of severe, spasmodic cough may be followed by vomiting, cyanosis and convulsions.
Dangerous complications of pertussis
Bronchopneumonia and acute encephalopathy
In addition to the endotoxin, B.pertussis produces an exotoxin called…….
Pertussis toxin
the most important pathogenic species in the genus Legionella.
Legionella pneumophila
The best culture medium for L. pneumophila
buffered charcoal yeast extract agar (BCYE agar)
Mode of transmission for legionella&source
Mainly environmental water sources, NO person to person transmission.
Diseases caused by L. pneumophila
1- Atypical pneumonia (Legionnaires disease j
2- Pontiac fever
Enumerate/ 4 causes of atypical pneumonia :
Legionella pneumophila
Mycoplasma pneumoniae
Viral pneumonia such as influenza
Q fever
The genus …….. (acid fast bacilli) difficult to stain with ordinary stains
Mycobacterium
….. & ……. Are the cause of TB in human
M. tuberculosis & M. bovis
G.r / M.tuberculosis can’t be stained by simple stains
Due to the high lipid content (mycolic acids) of the cell wall.
Enumerate / high conc. of lipids (mycolic acids) leads to:
- acid fast bacilli
- resistance to many antibiotics
- resistance to killing by acidic and alkaline compounds
- resistance to phagocytosis and interacellular destruction.