Bacteriology Test Questions – Flashcards
Unlock all answers in this set
Unlock answersquestion
| Acid-fast |
answer
| Mycobacterium Nocardia (partial) |
question
| Aerobic respiration |
answer
| oxidation of substrates coupled to electron transport with O2 as final electron acceptor 38 ATP/glucose |
question
| Aerointolerant |
answer
| anaerobes with non-oxygen final electron acceptors very sensitive to oxygen radicals quite a few of the medically relevant bacteria |
question
| Aerotolerant |
answer
| anaerobes with non-oxygen final electron acceptors can detoxify oxygen radials with superoxide dimustase and catalase quite a few of the medically relevant bacteria |
question
| Anaerobic respiration |
answer
| oxidation of substrates coupled to electron transport with different final electron acceptor (not O2) less efficient than aerobic: 30 ATP/glucose |
question
| Antigenic variation |
answer
| make surface proteins look different to immune system than did previous generation |
question
| Autolysins |
answer
| enzymes produced by bacteria that break Beta-1,4 glycoside bonds of PG used during growth and division |
question
| Auxotroph |
answer
| requires at least one organic product from environment b/c can't synthesize it |
question
| Capsule |
answer
| hydrophyilic gell that is carbohydrate based anti-phagocytic function seen as halo after India ink staining |
question
| Cell wall |
answer
| provides shape and rigidity protects against osmotic lysis acts as semi-permeable barrier transport site protects from host defense mechanisms mediates adherence senses and signals about the environment provides motility |
question
| Conjugation |
answer
| DNA is transferred directly by cell-to-cell contact extremely efficient exchange of genetic information one bacterium must of a self-transmissible plasmid (F plasmid) |
question
| Core |
answer
| domain of the LPS diversity of sugars, used to classify species KDO - 8C sugar, 1st attached to Lipid A 7C sugars follow, then regular sugars polarity of core prevents hydrophobic passage across OM |
question
| Death phase |
answer
| toxic products build up and autolytic enzymes forming death rate exceeds growth rate seen in body when immune system is winning |
question
| Definitive (specific) therapy |
answer
| specific diagnosis available narrow drug choice to avoid NF damage and opening areas as new infection site |
question
| Drug targets of prokaryotic cells |
answer
| supercoiled bacteria (no chromatin or histones) complex cell wal 70S ribosomes (not 80S) |
question
| Empirical therapy |
answer
| based on most probably cause of infection no specific dx yet/available reserved for emergency situations use broad drug choice, sometimes combination of drugs |
question
| Endospore advantages |
answer
| resist boiling, radiation, desiccation, and most enzymes/chemical disinfectants respiratory, wound or oral transmission |
question
| Endospore forming genera |
answer
| Bacillus Clostridium (G+) |
question
| Endospore parts |
answer
| core - highly dessicated DNA, tRNA, amino acids, nucleic acids and other essential cytoplasmic components cortex - condensed form of cell wall spore coats - protein-based coat that is put on by mother cell |
question
| Faculative anaerobes |
answer
| uses O2 or inorganic electron acceptors adapts to multiple environmental niches most flexible group most of the medically relevant bacteria |
question
| Fermentation |
answer
| no electron acceptor available, oxidation of substrates leaves organic products less efficient that an(aer) respiration |
question
| Flagella |
answer
| thicker, longer projections (compared to pili) funtion: locomotion in response to chemical gradient polar - out of one end peritrichous - all over cell |
question
| Generalized transduction |
answer
| Virulent bacteriophage involved Bacterial DNA is packaged into viral capsid instead of bacteriophage DNA |
question
| Gram negative, coccus |
answer
| Neisseria |
question
| Gram negative, pleomorphic |
answer
| Chlamydia Rickettsiae |
question
| Gram negative, rod, enterics |
answer
| Escherichia coli Shigella Salmonella Yersinia Klebsiella Proteus Enterobacter Helicobacter Serratia Vibrio Campylobacter Pseudomonas Bacteroids |
question
| Gram negative, rod, non-enterics |
answer
| Haemophilus Bordetella Legionella Yersinia Francisella Brucella Pasteurella Gardenerella |
question
| Gram negative, spiral |
answer
| Treponema Borrelia Leptospira Require darkfield microscope to see |
question
| Gram positive, branching |
answer
| Actinomyces Nocardia |
question
| Gram positive, coccus |
answer
| Streptococcus Staphylococcus |
question
| Gram positive, rod |
answer
| Corynebacterium Listeria Bacillus Clostridium |
question
| Gram-negative cell wall |
answer
| 3-5nm thick PG layer emphasizes fluidity 2nd membrane with LPS outside PG layer |
question
| Gram-positive cell wall |
answer
| 20-30nM thick PG layer emphasizes sturdiness one membrane, no LPS |
question
| Heterotroph |
answer
| requires organic matter for energy source, most of the relevant bacteria |
question
| Insertion sequences |
answer
| repeats, hot spot for recombination |
question
| KDO |
answer
| 8-carbon sugar of core of LPS that is always the first one or couple sugars attached to Lipid A |
question
| LPS |
answer
| unique G- molecule Lipid A, core and O antigen domains |
question
| Lag phase |
answer
| initiation of culture, adjustment to new environment sensing what is and isn't available in media |
question
| Lipid A |
answer
| domain of LPS endotoxin highly conserved between bacteria GlcNac dimers connected by phosphates that have fatty acid chains the fatty acids are highly branched and saturated --> unique to bacteria fatty acis prevent hydrophilic molecules from passing OM of G- cell |
question
| Lipoteichoic acid |
answer
| unique to G+ bacteria, derived from techoic acid glycerol phosphates linked with fatty acids pro-inflammatory molecule |
question
| Log/exponential growth phase |
answer
| rapid growth, as fast as possible in provided media measured in turbidity (cloudiness) using spectrophotometer seen in privileged sites in body (low NF and low immune presence) |
question
| Lysozyme (muramidase) |
answer
| enzymes in human body fluids that break Beta-1,4 glycoside bonds of PG more effective against G+ than G- |
question
| MBC |
answer
| minimal bactericidal concentration min. conc. needed to kill 99.9% of organisms |
question
| MIC |
answer
| minimal inhibitory concentration min. conc. needed to inhibit bacterial growth |
question
| Microaerophiles |
answer
| don't do aerobic respiration, but require oxygen for other essential purposes must have LOW levels of oxygen few of the medically relevant bacteria |
question
| O antigen |
answer
| part of LPS polymer of sugar units highly diverse, used to classify strains of species polarity of prevent passage of hydrophobic molecules |
question
| Obligate aerobes |
answer
| require oxygen for life some are medically relevant |
question
| Peptidoglycan (PG) |
answer
| unique to bacteria long glycan chains cross-linked by short peptides determines physical integrity and shape of cell wall highly polar =<100,00Da pass pro-inflammatory molecule |
question
| Periplasm |
answer
| "space" between membranes of G- bacteria where PG layer is located has lots of proteins used for transport |
question
| Pili |
answer
| hair-like, very small projections function: attach to host cell, sex for genetic info transfer |
question
| Plasmids |
answer
| extrachromasomal DNA provide accessory, non-essential information (virulen, antiB resistance) typically circular, single or multi copies sorting between daughter cells is not well organized, can result in loss of copies or information |
question
| Porins |
answer
| proteins of outer membrane of G- bacteria trimerize to form channel through membrane that aids in nutrient attainment |
question
| Prokaryotic chromosomes |
answer
| 1-10Mbases, 10^3 to 10^4 genes haploid supercoiled in nucleoid region |
question
| Prokaryotic cytoplasmic membrane |
answer
| selectively permeable carrier-mediated transport electron transport system |
question
| Prototroph |
answer
| can synthesize all organic products that it needs; does not require any from its environment |
question
| Quorum sensing |
answer
| ability to sense own population and alter gene expression based on that info |
question
| R factor |
answer
| F' plasmid with drug resistance genes on plasmid transferred via conjugation always implies transfer of drug resistance |
question
| Regulon |
answer
| multiple operons under control of a single transcription regulator |
question
| Specialized transduction |
answer
| Temperate bacteriophage involved error in splicing of phage DNA from the bacterial DNA, results in mixed DNA in phage packages |
question
| Stationary phase |
answer
| nutrients are running low, no net growth seen metabolically inactive, quiet see in walled off abscess of body not good for some antiBs b/c only work on actively dividing cells |
question
| Targets for antibiotics |
answer
| cell-wall synthesis cell membrane DNA integrity folic acid synthesis protein synthesis (30S or 50S) RNA synthesis |
question
| Teichoic acid |
answer
| unique to G+ bacteria series of phosphate-linked surgars with glycerol or ribitol phophate-linkages has substiuents like D-Ala that are bacteria unique pro-inflammatory molecule |
question
| Transduction |
answer
| Bacteriophage carries bacterial DNA from one bacterium to others |
question
| Transformation |
answer
| Naked DNA fragments released from one lysed bacterium binds to cell wall of another competent bacterium and is taken up and incorporated into the new bacterium's chromosome |
question
| Transposase |
answer
| recognizes sequence of DNA, opens it, inserts a copy of itself and transposon |
question
| Transposon |
answer
| moveable elemtsn of DNA consists of insertion sequences, virulence/resistance genes, and transposase encoding |
question
| Two-component regulators |
answer
| consists of sensing extra-cellular component, transmembrane domain, and intracellular signaling domain recognizes signal from external environemnt, autophosphorylates tail, tail phosphorylates regulator, signal cascade proceeds and gene expression is altered |
question
| Mechanism of adverse reactions to drugs |
answer
| direct toxicity sensitivity superinfections |
question
| Optimal salinity, temp and pH |
answer
| 0.85% 30-37*C 6-8pH |
question
| Resistance strategies |
answer
| prevent drug access to target modify drug modify target of drug change metabolic status of bacterium |
question
| Prevention of drug access |
answer
| barrier lack of binding target anaerobic for O2-dependent drugs lack of activating enzyme alteration in porins efflux pumps |
question
| MLS(R) phenotype |
answer
| overlapping binding site of multiple drugs is effect by one methylation change in rRNA due to presence of erm gene |
question
| Stratgies for drug resistance |
answer
| prevent access to target modify drug modify drug's target modify metabolism (state or processes) |
question
| Commensal |
answer
| bacterium that causes no apparent disease es: normal flora |
question
| Opportunistic pathogen |
answer
| can cause disease, but depends on right conditions ex: +/- virulence factor, host barrier status and host immune status |
question
| Obligate pathogen |
answer
| always causes disease |
question
| Extracellular Bacteria |
answer
| Path - resist phagocytosis Disease - acute onset, faster resolution, unless biofilm Fever - usually WBC - PMNs, pus formation Clearance - by humoral immunity |
question
| Intracellular Bacteria |
answer
| Path - survive in host cells Disease - chronic infection, slower onset and recovery Fever - maybe WBC - macrophage, lymphocytes Cleared - by cell-mediated immunity |
question
| Tropism |
answer
| selective infection of specific tissues or cells |
question
| Siderophores |
answer
| bacteria enzyme with high affinity for Fe3+, chelators strip Fe3+ from lactoferrin and transferrin |
question
| Fe-binding receptors |
answer
| bacterial molecules that help with Fe scavenging bind Fe-loaded siderophores, bind free Fe3+ and bind Fe-loaded host molecules |
question
| Exotoxins |
answer
| act distal to infection site commonly enzymes that damage host directly disrupt host processes or membrane AB toxins, non-AB toxins, activation requirements |
question
| Endotoxins |
answer
| elicit inflammatory response and activates complement --> cell damage indirectly part of outermembrane of G- bacteria |
question
| AB toxins |
answer
| protein complex of 2 subunits A = active subunit, enters host cell and has toxic effects B = binding subunit and delivers A to susceptible cell |
question
| Host cell process-disruption by exotoxin |
answer
| protein synthesis signaling (G-proteins) ADP-ribosylation (inactivates proteins, shut down pathway) |
question
| Host cell membrane-disruption by exotoxin |
answer
| osmotic balance -> lysis phospholypases -> digest membrane pore-formation -> lysis/permeability hemolysins -> lyse RBC, release Fe` |
question
| Autoinducers |
answer
| molecules that serve as signals of population density G- = HSL G+ = peptides |
question
| Type III Secretory Apparatus |
answer
| "molecular syringe" structure that bacterial cell inserts into host membrane and injects effector into host cytoplasm effectors: induce apoptosis, suppress cytokine production, shut down phagocytosis, etc. |
question
| Polymicrobial biofilm |
answer
| mixed infection, i.e. wound or areas of normal flora (pathogen binds to biofilm of normal flora) particularly advantageous |
question
| Monomicrobial biofilm |
answer
| only one pathogen, usually in sterile site |
question
| Sessile cells |
answer
| bacteria located in biofilm not moving, less active |
question
| Planktonic cells |
answer
| bacteria of biofilm colony that aren't in the biofilm, free-floating, more active capable of leaving to form new colonies elsewhere |
question
| Advantages of biofilm |
answer
| adherence, nutritional opportunity, protected environment extracellular bacteria can cause chronic infection this way |
question
| Sialyation of LPS |
answer
| molecular mimcry, prevents MAC deposition (i.e. complment mediated cytosis) |
question
| C5a peptidase |
answer
| counter strategy of bacteria to complement system prevents inflammatory response |
question
| Invasins |
answer
| proteins expressed by bacteria that rearrange cytoskeleton in host cell induce actin polymerization that forms pseudopods and takes in bacteria forces phagocytosis by non-pros |
question
| Systemic Inflammatory Response Syndrome (SIRS) |
answer
| abrupt on set of 2: fever, tachycardia, tachypnea, and leukocytosis can be due to infection or severe trauma with lots of tissue damage good prognosis if underlying issue is solved |
question
| Sepsis |
answer
| clinical symptoms of SIRS + documentation of bacterial infection progression to severe sepsis guaranteed |
question
| Bacteremia |
answer
| viable bacteria in blood stream, document by Gram stain possible migration though body, does not require SIRS symptoms for Dx, usually transient |
question
| Severe sepsis |
answer
| Sepsis (SIRS + documentation) and signs of organ failure DIC --> organ damage 1* COD is resp. failure |
question
| Disseminated intravascular coagulation |
answer
| dysfunction in clotting cascade abnormal clotting and bleeding poor perfusion to organs --> damage seen in severe sepsis |
question
| MODS |
answer
| multiple organ dysfunction of syndrome worsening situation of severe sepsis |
question
| Septic shock |
answer
| severe sepsis (SIR + documentation + organ failure) and extreme hypotension profoundly low BP that is unresponsive to fluid treatment |
