FINAL Micro Minimals Flashcards
Describe the colour (in a Gram stained smear) of Gram positive and Gram negative
bacteria, respectively!
Gram positives: dark blue (purple)
Gram negatives: red (pink)
Describe the 3 important parts of the bacterial lipopolysaccharide!
lipid A + core polysaccharide + O-specific (polysaccharide) side chain
Which 2 roles are attributed to bacterial pili (fimbriae)?
adhesion; conjugation (sex fimbriae)
Mention a bacterium and its virulence factor that is encoded by a lysogenic
bacteriophage!
Corynebacterium diphtheriae – diphtheria toxin
Streptococcus pyogenes – erythrogenic toxin
Escherichia coli – verotoxin
Clostridium botulinum- botulinus toxin
List the possible shapes of bacteria. Write one example for each category!
coccus (spherical): Staphylococcus, Streptococcus
rod: Clostridium, Corynebacterium, E. coli
curved rod: Vibrio
helical: Treponema, Borrelia, Leptospira
What are the essential components of bacterial cells? Specify at least 3!
cytoplasm, nucleoid (genome), cell membrane, (cell wall)
Which part of the bacterial cell carries the endotoxin?
Outer membrane of Gram negative bacteria
What roles are attributed to the bacterial capsule in the infectious process?
antiphagocytic effect, adhesion
Describe the definition for obligate anaerobic bacteria!
They are able to replicate only in the absence of oxygen (under anaerobic conditions).
Some of them are quickly killed by oxygen, some are able to survive but do not grow
while oxygen is present.
Describe the definition for facultative anaerobic bacteria!
They are able to replicate both in the presence and in the absence of oxygen. In aerobic
conditions, they perform respiration, in anaerobic condition, they perform fermentation.
What does sterilisation mean?
Sterilisation means the killing or removal of all microorganisms (including bacterial
spores).
Mention 3 reliable methods of sterilization!
autoclaving, hot air oven, gamma-radiation, filtration (fluids), gas sterilisation
(not acceptable: boiling, pasteurisation, UV!)
Specify an exact set of parameters (temperature and time) necessary for effective
sterilization by autoclaving!
121 °C for 20 - 30 min. (at 1 bar overpressure)
Specify an exact set of parameters (temperature and time) necessary for effective
sterilization using a hot air oven (with circulation)!
160 °C for 60 min.
What does disinfection mean?
The purpose of disinfection is the killing of pathogenic microbes and to decrease the
number of viable microbial cells. Resistant microbes and spores may survive, so
disinfection does not the kill all microbes.
Mention 5 groups of disinfectants!
alcohols, phenol derivatives, detergents,
chlorine, iodine, aldehydes
Mention 2 groups of disinfectants acting on the microbial membrane structures!
a., (cationic) detergents (quaternary ammonium compounds)
b., phenol compounds (cresol, hexachlorophene, chlorohexidine)
c., alcohols (ethanol, isopropanol)
What does active immunisation mean?
It means the transfer of microbes or microbial products (vaccines) to the human body
to induce long-lasting immunity against a specific infectious disease
What does passive immunisation mean?
It means the administration of preformed antibody (immune globulins produced in
animals or humans) to the human body resulting in short-term protection against a
specific infectious disease
Mention 2 bacterial infectious diseases that can be prevented or treated by passive
immunisation!
prevention: tetanus
treatment: diphtheria, botulism, tetanus
Describe precisely what toxoid means!
Inactivated bacterial exotoxin that is not toxic but immunogenic
Mention 2 infectious diseases that can be prevented by vaccines containing toxoids!
Diphtheria, tetanus, (pertussis)
What does the DTaP vaccine contain?
diphtheria and tetanus toxoids and
acellular pertussis vaccine (toxoid and other purified antigens)
What does the vaccine against tuberculosis (BCG) contain?
live attenuated Mycobacterium bovis (Bacille Calmette-Guerin)