VIRBO Flashcards
Character of vibrio cholerae
- Gram negative rod
- Oxidase positive
- Glucose & sucrose fermenter
- Motile (flagella)
- Acid labile
- NON INVASIVE
Hallmark characteristics of vibro species
Biochemical tests: Oxidase positive
Histology: curved (comma) gram negative rods
Transmission of vibrio cholerae
faecal oral
Treatment of vibrio cholerae
- oral rehydration therapy (replace electrolytes and fluid), severe cases may require IV infusion
- ciprofloxacin/tetracycline (reduces period of pathogen excretion & severity of diarrhoea)
Virulence factor of vibrio cholerae
Cholera toxin
- B subunit (immunogenic): binds to ganglioside receptor on the luminal membrane of enterocytes
- A subunit: crosses the membrane and activates adenylate cyclase → over-production of cAMP, inhibits active reabsorption of Na+ and HCO3- and water & causes hypersecretion of Cl- and HCO3- with enormous water loss
- note: strains which lack pili and do not have flagellum are not virulent
Transmission of vibrio parahaemolyticus
Contaminated seafood
Transmission of vibrio vulnificus
Contaminated seafood, contact between seawater and wounds
Clinical presentation of vibrio vulnificus
Food poisoning: self limiting diarrhoea
Acute septicaemia in immunosuppressed individuals (high fever, hypotenion and multiple erythematous skin lesions which become hemorrhagic, necrotic and ulcerating)
Wound infections: cellulitis accompanied by edema, erythema and life-threatening necrosis
Treatment of vibro vulnificus
Aggressive surgical wound debridement + combinations of doxycycline, ceftazidime and ciprofloxacin
Characteristics of acinetobacter baumannii
NOT fastidious, gram negative rod
Found in the environment and is also normal skin flora
Clincial presentation of acinetobacter baumannii
Nosocomial pneumonia due to immunocompromisation
ICU pneumonia, burn patients
Often resistant to multiple antibiotics
Clinical presentation of bordetella species
Whooping cough
- catarrhal stage: resemble other respiratory infections
- paroxysmal stage: paroxysmal cough (lungs emptied in a series of cough before dragging in a fresh breath through a narrowed throat which produces the whoop)
transmission of bordetella species
respiratory droplets
character of legionella pneumophilia
fastidious gram negative bacteria
environmental, grows in water
transmission of legionella pnuemophilia
infectious aerosol from colonised water source dispensers (NOT person to person, NOT airborne)
clinical presentation of legionella pneumophilia
legionnaires’ disease: severe pneumonia frequently accompanied by confusion/extra-pulmonary manifestations
pontiac fever: brief influenza-like illness, less dangerous
diagnosis of legionella pneumophilia
favourite test: antigen detection of urine
immunofluorescent stain on sputum
sample/bronchoalveolar lavage (BAL)
serology
treatment of legionella pneumophilia
high dose IV erythromycin/azithromycin (macrolide) or with rifampicin
treatment of bordetella species
erythromycin (reduces severity of illness if given before the paroxysmal stage)
transmission of yesinia pestis
zoonosis (often through bite of rat flea as it infects rodents), respiratory droplets
clincial presentation of yersinia pestis
bubo formation (painful swelling of lymph nodes) with subsequent invasion of bloodstream → pneumonia and septicaemia (plague)
Transmission of burkholderia pseudomallei
Direct inhalation of aerosolised bacterium from surface soils and water
Direct inoculation: skin abrasions/contact with superficial wounds
