3 Review Of Medical Microbiology Flashcards
Prokaryotic organisms
Unicellular organisms that lack a true nucleus and nuclear membrane
Bacteria
Single, closed circular chromosome of double-stranded DNA
Nucleiod
Has nucleiod, plasmid and chromosomal or plasmid exchange via transformation, transduction or conjugation
Genome
3 Means of genetic recombination
Transformation
Transduction
Conjugation
Energy generation of bacteria?
Electron transport chain
Size of bacteria
0.2 to 2 um in diameter and 1-6 um in length
3 nutritional needs of bacteria
Carbon
Nitrogen
Energy (ATP)
Needed for synthesis of cellular constituents
Carbon
Necessary for synthesis of protein
Nitrogen
Needed for cellular functions
Energy
Optimum pH for growth
7.0 to 7.5
Optimum growth temperature
35 to 37 degree celsius
Require oxygen for growth
Obligate aerobes
Grow in the presence of oxygen but grow best in anaerobic environment
Aerotolerant aerobes
Grow in both aerobic and anaerobic environments
Facultative anaerobes
Cannot grow in the presence of oxygen
Obligate anaerobes
Require concentrations of 5% to 10% CO2 for optimal growth
Capnophilic
Grow optimally in a reduced level of oxygen
Microaerophilic
Anaerobic process by which bacteria catabolize carbohydrates to produce energy
Carried out by both obligate and facultative anaerobes
Fermentation
Final electron acceptor in fermentation
Organic compound
Efficient process by which obligate aerobes and facultative anaerobes generate energy
More efficient mechanism for energy generation than fermentation
Respiration(oxidation)
Final electron acceptor of respiration
Molecular oxygen
Osmotic barrier and may be a site of antibiotic infection
Essential for bacterial viability
Cell membrane
Thick, rigid peptidoglycan layer
Site of action of penicillin and cephalosporin
Gram positive cell wall
Component of gram positive wall
Teichoic and lipoteichoic acids
Thinner peptidoglycan layer, but also an outer LPS layer
Gram negative wall
Virulence factor
Causes shock, sepsis, fever, DIC, and leukopenia
Endotoxin
Prevent or inhibit phagocytosis
CHIEF DTERMINANT OF VIRULENCE
Capsule
Short, hairlike structures that serve to attach bacteria to target cells
Pili/Fimbriae
Exchange of DNA between bacteria during conjugation
Conjugation pili
Example of bacteria that uses conjugation pili
Interference with attachment prevents infection
Neisseria gonorrhoeae
Means of survival that make disease control very difficult
Flagella
Spore forming genera
Bacillus and clostridium
Examines smears of clinical specimen
Initial treatment, and often presumptive ID can be made
Composition of it and its function
Gram’s stain V primary stain I Mordant-binds crystal violet to cell wall A wash out any unbound dye S Counterstain
Serves as internal control in gram stain that act as cellular debris
Stain pink
WBC AND RBC
Orange fluorescent stain that is used to detect bacteria in body fluids
Very sensitive and can detect small numbers of bacteria that are living or dead
Acridine orange stain
Detect bacteria in direct smears with excess cellular debris
Acridine orange stain