Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Microbiology
FA complete review part 1 Cellular, Genetics, and Categories
| Question | Answer |
|---|---|
| What is the function of flagellum? | Motility |
| What is the function of Pilus/fimbriae? | Mediate adherence of bacteria to cell surface; sex pilus forms during conjugation |
| What is the chemical composition of a spore? | Keratin-like coat; dipicolinic acid; peptidoglycan , DNA |
| Which type of bacteria have spores? | Gram (+) only |
| What is the main function or purpose of a spore? | Survival: resists dehydration, heat, and chemicals |
| What is the composition of a CAPSULE? | Organized, discrete polysaccharide layer |
| What it the function of a capsule? | Protects against phagocytosis |
| What cellular structure is in charge of protecting against phagocytosis? | Capsule |
| Composed of loose network of polysaccharides? | Glycocalyx |
| What is the function of Glycocalyx? | Mediates adherence to surface, especially foreign surfaces |
| What is the the exception of Capsule? | Poly-D-glutamate on B anthracis |
| What are the 3 main components of the Outer membrane? | 1. Outer leaflet 2. Embedded proteins 3. Inner leaflets |
| What is the composition of outer leaflets of the outer membrane? | Endotoxin (LPS/LOS) |
| Phospholipids is the main component of which part of the outer membrane? | Inner leaflet |
| What kind of bacteria is the only one with outer membrane? | Gram negative only |
| What are the role of porins in the outer membrane? | Transport across the membrane |
| What is the role of Lipid A? | Induces TNF and IL-1 |
| What is the space between cytoplasmic membrane and outer membrane in gram (-) bactria? | Periplasm |
| What is in the middle of the Periplasm? | Peptidoglycan |
| What is the function of the periplasm? | Accumulates components exiting gram (-) cells, including hydrolytic enzymes |
| What is the composition of the Cell wall? | Peptidoglycan is a sugar backbone with peptide side chains cross-linked by transpeptidase |
| What is the main function of the cell wall? | Net-like structure gives rigid dsupport, protects against osmotic pressure damage |
| What are the two roles of the Cytoplasmic membrane? | 1. Site of oxidative and transport enzymes; PBPs involved in cell wall synthesis 2. Lipoteichoic acids induce TNF-alpha and IL-1. |
| What are the main components of the cytoplasmic membrane? | - Phospholipid bilayer sac with embedded proteins and other enzymes - Lipoteichoic acids (gram (+) only) extend from membrane to exterior |
| What cell envelope structures are exclusive of gram (-) bacteria? | Outer membrane (Endotoxin/LPS, porin), and Periplasmic space |
| Lipoteichoic acid is unique to gram _________ bacteria. | Positive |
| What is another way to refer to spherical morphology? | Coccus |
| Coccus gram negative bacteria: | 1. Moraxella catarrhalis 2. Neisseria |
| What are common pleomorphic (no cell wall) gram negative bacteria? | Anaplasma, Ehrlichia, Chlamydiae, Rickettsiae, Mycoplasma, and Ureaplasma |
| Which bacteria is identified with Giemsa stain? | Rickettsia, Chlamydia, Trypanosomes, Plasmodium, Borrelia |
| A bacteria with a thick peptidoglycan layer will stain what color? | Violet |
| Thin peptidoglycan wall bacterial stains __________________, in color. | Pink or red |
| Which bacteria do not stain well do to lack of peptidoglycan wall due to decreased muramic acid? | Legionella, Rickettsia, Chlamydia, Bartonella, Anaplasma, and Ehrlichia |
| What is similar in Mycoplasma and Ureaplasma? | NO cell wall |
| Cell wall too thin to be visualised is seen in: | Treponema and Leptospira |
| Mycobacteria does not stain well because: | Cell wall has high lipid content |
| What condition is diagnosed with Periodic acid-Schiff stain? | Whipple disease |
| What is primarily stained with Periodic acid-Schiff stain? | Glycogen and mucopolysaccharides |
| Acid-fast bacteria most commonly include: | Mycobacteria and Nocardia |
| Ziehl-Neelsen stain is also known as: | Carbol fuchsin |
| What substance is stained with Ziehl-Neelsen stain? | Mycolic acid in cell wall |
| What bacteria or organism are stained with Ziehl-Neelsen stain? | Acid-fast bacteria and Protozoa |
| Identification of Cryptosporidium oocysts with stain is done with: | Ziehl-Neelsen stain |
| What stain is used in Cryptococcus neoformans identification? | India ink stain |
| What stain is used in fungi? | Silver stain |
| For what is Silver stain used? | Fungi, Legionella, and H. pylori |
| What is the main function of Selective media? | Favors the growth of particular organisms while preventing growth of other organisms |
| What is a common example of a Selective media? | Thayer-Martin agar |
| What is Indicator (differential) media function? | Yields color change in response to the metabolism of certain organisms |
| MacConkey agar is an example of ___________________media. | Indicator (diffencital) |
| How is the color change indicated by a differential media? | Due to changes in pH |
| What is the media used in H. influenzae? | Chocolate agar |
| What are components of Chocolate agar? | Factors V (NAD+) and X ( hematin) |
| Media made of Factor V (NAD+) and X (hematin). | Chocolate agar |
| What type of media is used for Neisseria species? | Thayer-Martin agar |
| In Thayer-Martin media, the growth of gram positive organism is done with _______________. | Vancomycin |
| What antibiotics are included in Thayer Martin agar to inhibit growth of gram negative bacteria, except Neisseria? | Trimethoprim and Colistin |
| Nystatin is used to inhibit __________ growth in Thayer Martin agar. | Fungi |
| Media used for B. pertussis | Bordet-Gengou agar |
| What is the component of Bordet-Gengou agar? | Potato extract |
| What is the components of Regan-Lowe medium? | Charcoal, blood, and antibiotic |
| What organism uses Regan-Lowe medium? | B. pertussis |
| Tellurite agar + Loffer medium are used for _________________ growth. | C. diphtheriae |
| Agar used to M. tuberculosis? | Lowenstein-Jensen agar |
| M. pneumoniae uses ___________ agar and requires _____________. | Eaton agar; Cholesterol |
| What media is used by Lactose-fermenting enterics? | MacConkey agar |
| Fermentation caused in a MacConkey agar culture, turns colonies __________ (color) | Pink |
| What media is often used by E. coli growth? | Eosin-methylene blue (EMB) |
| What is the color of E. coli colonies been cultured with EMB? | Green metallic sheen |
| What characteristic media is used by Legionella? | Charcoal yeast extract agar buffered with cysteine and iron |
| Sabouraud agar is used to grow cultures of __________. | Fungi |
| What are common examples of Anaerobes? | Clostridium, Bacteroides, Fusobacterium, and Actinomyces israelii. |
| What are enzymes are lacking in Anaerobic? | Catalase and/or superoxide dismutase |
| What are some key features used to describe and identify anaerobes? | 1. Foul-smelling (short-chain FAs) 2. Difficult to culture 3. Produce gas in tissue |
| Where in the body are anaerobes usually part of the normal flora? | GI tract |
| Which class of antibiotics are ineffective to anaerobes? | Aminoglycosides |
| What is the characteristic definition of Facultative anaerobes? | May use O2 as a terminal electron acceptor to generate ATP, bu can also use fermentation and other O2-independent pathways |
| Which class of bacteria are a mixed of anaerobes and anaerobes? | Facultative anaerobes |
| What are some common Facultative anaerobes? | Streptococci, staphylococci, and enteric gram (-) bacteria |
| What are the two classes of INTRACELLULAR bugs? | Obligate and Facultative |
| What organisms are Obligate intracellular? | RIckettsia, Chlamydia, Coxiella |
| Which class of organism rely on host ATP? | Obligate intracellular |
| List of Facultative intracellular bacteria: | 1. Salmonella 2. Neisseria 3. Burcella 4. Mycobacterium 5. Listeria 6. Francisella 7. Legionella 8. Yersinia pestis |
| Salmonella, Mycobacterium, Listeria, Legionella, and Yersinia pestis are examples of _______________________ bacteria | Facultative intracellular |
| What are the most common Encapsulated bacteria? | Streptococcus pneumoniae, H. Influenzae type b, Neisseria meningitidis, E. coli, Salmonella, Klebsiella pneumoniae, and group B Strep |
| What is the role of the capsules of "Encapsulated" bacteria? | Serve as antiphagocytic virulence factor |
| Capsular polysaccharide + protein conjugate = | Antigen in vaccines |
| What mnemonic is used for Encapsulated bacteria? | Please SHINE my SKiS |
| how are encapsulated bacteria cleared from body? | Opsonized and cleared by the spleen |
| Which type of patients are at higher risk of encapsulated bacterial infections? | Asplenics |
| Available vaccines for Encapsulated bacteria (3): | 1. N. meningitidis 2. S. pneumoniae 3. H. influenzae type b |
| What is the purpose of Encapsulated bacteria vaccines composition? | Polysaccharide capsule is conjugated to carrier protein, in order to enhance immunogenicity by promoting T-cell activation and subsequent class switching |
| Mnemonic used for Urease- positive organisms: | Pee CHUNKSS |
| Pee CHUNKS stands for: | Proteus, Cryptococcus, H. pylori, Ureaplasma Nocardia Klebsiella S. epidermidis S. saprophyticus |
| Urease positive organism predispose to which type of kidney stone? | Struvite |
| Which urease (+) organism most commonly predisposes to Struvite formation? | Proteus |
| What is the function of Urease? | Hydrolyses urea to release ammonia and CO2 ---> increase in pH |
| What is the function of Catalase? | Degrades H2O2 into H2O and bubbles of O2 before it can be converted to microbicidal products by the enzyme myeloperoxidase |
| What immunodeficiency is often have higher risk of catalase (+) organism infections? | Chronic granulomatous disease |
| Examples of Catalase (+) organisms: | Nocardia, Pseudomonas, Listeria, Aspergillus, Candida, E. coli, Staphylococcus, Serratia, B cepacia, and H pylori |
| Nocardia, Pseudomonas, E. coli, H. pylori, Serratia, and H. pylori are all ___________ positive organisms | Catalase |
| C cepacia is __________ positive | Catalase |
| Yellow "sulfur" granules seen with: | Actinomyces israelii |
| What color pigment is seen with S. aureus? | Yellow |
| Blue-green pigment is associated with: | P. aeruginosa |
| Color pigment associated with Serratia? | Red |
| What infections are associated with S. epidermidis biofilm production? | Catheter and prosthetic device infections |
| What are some biofilm-producing bacteria? | S. epidermidis, Viridans streptococci, P. aeruginosa, and nontypeable H. influenzae. |
| Dental plaques, infective endocarditis ar due to biofilms produced by ______________________. | Viridans streptococci |
| What conditions are associated with P. aeruginosa biofilm production? | 1. Ventilator-associated pneumonia 2. Contact lens-associated keratitis 3. Respiratory tree colonization in CF patients |
| What is the purpose of Bacterial virulence factors? | Promote evasion of host immune response |
| What organism has Protein A virulence factor? | S. aureus |
| IgA protease is a virulence factor seen with: | S. pneumoniae, H. influenzae type b, and Neisseria |
| Which virulence factor binds to Fc region of IgG? | Protein A |
| After binding, what actions are prevented by Protein A? | Opsonization and phagocytosis |
| What is the function virulence factor IgA protease? | Enzyme that cleaves IgA, allowing bacteria to adhere to and colonize mucous membranes |
| M protein helps prevent _____________. | Phagocytosis |
| What kind of bacteria expresses M protein virulence factor? | Group A streptococci |
| What is a possible underlying reason for the autoimmune response seen in acute rheumatic fever? | M protein |
| Shares similar epitopes to human cellular proteins (molecular mimicry) | M protein |
| What is another name for Type III secretion system? | Injectisome |
| What is an injectisome? | Needle-like protein appendage facilitating direct delivery of toxins from certain gram (-) bacteria to eukaryotic host cell |
| What is the process of bacterial Transformation? | Competent bacteria can bind and import short pieces of environmental naked bacterial chromosomal DNA |
| Besides IgA protease virulence factor, the SHiN bacteria, undergo ______________________ readily. | Transformation |
| What can prevent transformation? | Adding deoxyribonuclease degrades naked DNA |
| What are the two types of conjugation? | 1. F+ x F- 2. Hfr x F- |
| Which plasmid contains genes for sex pilus and conjugation? | F+ |
| What is transferred via the sex pilus? | Single strand of plasmid DNA |
| What is a plasmid? | Small, extrachromosomal DNA molecule within a cell |
| What kind of DNA is NOT transferred in Conjugation? | Chromosomal DNA |
| What is Hfr? | Plasmid that has incorporated the F+ plasmid |
| How is conjugation of chromosomal DNA possible? | Using Hfr only |
| What are the two modes of Transduction? | Generalized and Specialized |
| What mode of Transduction is referred as a packing "error"? | Generalized |
| What is generalized transduction? | Lytic phage infects bacterium, leading to clava of bacterial DNA. |
| Which transduction mode is referred as an "excision" event? | Specialized |
| What kind of phage is used in Specialized transduction? | Lysogenic |
| Transduction mode in which host and phage DNA break into little pieces? | Generalized |
| Newly formed phage capsids in Generalized transduction contain bacterial DNA , which then: | Infects other bacteria and creates then a recombinant DNA |
| In Specialized Transduction, instead of cleavage of bacterial DNA, it: | Viral DNA from the lysogenic phage incorporates in bacterial DNA |
| What is the difference in newly created phage capsids between Generalized and Specialized transduction? | In specialized, all the new phage capsids contain recombinant bacterial and viral DNA, which creates genes different from donor and recipient |
| Which are the 5 bacterial toxins aht are encoded in a lysogenic phage? | Group A strep erythrogenic toxin Botulinum toxin Cholera toxin Diphtheria toxin Shiga toxin |
| What is Transposition? | Segment of DNA that can "jump" from one location to another, can transfer genes form plasmid to chromosome and vice versa |
| What is the most common way to transfer plasmid with multiple antibiotic resistance among species? | Transposition |
| What are some key features of Spores? | 1. Lack metabolic activity 2. Highly resistant to heat and chemicals 3. Core contains dipicolinic acid |
| What temperature of an autoclave should be in other to kill spores? | 121 C for 15 minutes |
| Where are the endotoxins most likely located? | Outer cell membrane of most gram (-) bacteria |
| What is the main component of Endotoxins? | Lipid A component of LPS |
| Where are the genes located in a Endotoxin? | Bacterial chromosome |
| What are the most common clinical effects of an endotoxin? | Fever, shock (hypotension), and DIC |
| What is the MOA of endotoxins? | Induce TNF, IL-1, and IL-6 |
| What are the most typical diseases produced by Endotoxins? | Meningococcemia; Sepsis by gram (-) rods |
| Which are more toxic, Exotoxins or Endotoxins? | Exotoxins |
| Do exotoxins or endotoxins, produce antitoxins? | Exotoxins |
| Which can resist higher temperatures, exotoxins or endotoxins? | Endotoxins |
| How are exotoxins used in vaccines? | Toxoids produced are used as vaccines |
| What are the most typical exotoxin produced diseases? | Tetanus, botulism, and diphtheria |
| Which exotoxin producing organism inhibit protein synthesis? | Corynebacterium diphtheriae, Pseudomonas aeruginosa, Shigella spp., and Enterohemorrhagic E. coli. |
| Which bacteria's exotoxins inactivate elongation factor 2 (EF-2)? | Corynebacterium diphtheriae and Pseudomonas aeruginosa |
| What is C. diphtheriae clinical manifestation? | Pharyngitis with pseudomembranes in throat and severe lymphadenopathy (bull neck), myocarditis |
| What is P. aeruginosa exotoxin? | Exotoxin A |
| What is the clinical manifestation of Endotoxin A? | Host cell death |
| What is the mechanism of action of EHEC and Shigella spp toxins? | Inactivate 60S ribosome by removing adenine form rRNA |
| Which organisms' toxin inhibit protein synthesis by inactivating the 60S ribosome? | Shigella spp and EHEC |
| Which organism has Shiga-like toxin? | EHEC |
| What is the clinical manifestation of Shiga toxin? | 1. GI mucosal damage --> dysentery 2. Enhance cytokine release, causing HUS |
| What is a clinical difference of how Shigella and EHEC toxins act? | EHEC does not invade host cells |
| HUS is caused by which two organisms? | Shigella spp and EHEC |
| Which endotoxin containing organisms act by increase in fluid secretion? | ETEC, Bacillus anthracis, and Vibrio cholerae |
| What are the two exotoxins found in Enterotoxigenic E. coli? | 1. Healt-LABILE 2. Heat- STABLE |
| MOA of Heat-Labile ETEC exotoxin? | Over activates adenylate cyclase (increase cAMP --> increase Cl- secretion in gut and water efflux |
| Overactivates guanylate cyclase (increase cGMP) --> decrease resorption of NaCl and water n gut. | Heat-stable toxin of ETEC |
| What is the mode of action of Anthrax toxin? | Mimics adenylate cyclase |
| Which toxin is know to permanent activating Gs? | Cholera toxin |
| What organism is responsible for edematous border of black eschar in cutaneous anthrax? | Bacillus anthracis |
| Voluminous "rice-water" diarrhea | Vibrio cholerae infection |
| What organism causes Whooping cough? | Bordetella pertussis |
| What is the mode of action of Pertussis toxin? | Inactivates the inhibitory Gi --> activation of adenylate cyclase and increase of cAMP. |
| What is the analogue condition of Whooping cough in adults, called? | "100-day cough" |
| Pertussis toxin inhibits the _______________ ability. | Phagocytic |
| Which exotoxin interferes with optimal phagocytic activity? | Pertussis toxin |
| Which two common exotoxins inhibit the release of neurotransmitters? | Tetanospasmin and Botulinum toxin |
| What is the MOA of C. tetani and C. botulinum neurotoxins? | Proteases that cleave SNARE, a set of protein required for NT release via vesicular fusion |
| What NT release is inhibited by Tetanospasmin? | Inhibitory (GABA and glycine) NTs form Renshaw cells in spinal cord |
| GABA and glycine release is inhibited by _________________. | Tetanospasmin |
| What are the classic signs of Tetanus? | Spastic paralysis, risus sardonicus, and trismus (lockjaw) |
| What NT release is inhibited by Botulinum toxin? | Stimulatory ACh signal at Neuromuscular junction |
| What are the clinical findings of Botulism? | Flaccid paralysis |
| Which organisms' toxins lyse cell membranes? | Clostridium perfringens and Streptococcus pyogenes |
| What are the two associated exotoxins with Strep pyogenes? | 1. Streptolysin O 2. Erythrogenic exotoxin A |
| What is the MOA of alpha toxin in C. perfringens? | Phospholipase that debrades tissue and cell membranes |
| What is the name of the enzyme used in Alpha toxin? | Lecithinase |
| What organism causes "gas gangrene"? | Clostridium perfringens |
| What are the most common clinical manifestations of Clostridium perfringens? | 1. Degradation of phospholipids --> myonecrosis ("gas gangrene") 2. Hemolysis ("double zone") |
| What are antibodies against Streptolysin O? | ASO |
| What titer levels are used to Dx rheumatic fever caused by S. pyogenes? | ASO titers |
| Streptococcus pyogenes ANTIBODIES cause ________________. | Rheumatic fever |
| Streptococcus pyogenes immune complexes cause _______________________. | Poststreptococcal glomerulonephritis |
| What organisms have supertantiges causing shock exotoxins? | S. aureus and S. pyogenes |
| What is the mode of action of TSST-1 and Erythrogenic exotoxin A? | Cross-links B region of TCR to MHC class II on APCs outside ot the antigen binding site |
| What is the result of the cross link process of TCR and MHC II in superantigens? | Overwhelming release of IL-1, IL-2, IFN-gamma, and TNF-alpha ----> shock |
| What are the clinical manifestation of S. aureus Toxic shock syndrome? | Fever, rash and shock |
| Exfoliative toxin of S. aureus causes ---> | Scalded Skin Syndrome |
| What is characteristic manifestation of S. pyogenes Toxic Shock syndrome? | Fever, rash, shock, and Scarlet fever |
| What is the composition of LPS? | O antigen + core polysaccharide + lipid A |
| What is the toxic component of LPS composition? | Lipid A |
| What are the 3 main effects of LPS? | 1. Macrophage activation (TLR4/CD14), 2. Complement activation 3. Tissue factor activation |
| ENDOTOXINS is a menemoconc to remember what characteristic of endotoxins? | E- edema N- nitric oxide D- DIC/Death O- outer membrane T- TNF-alpha O- O antigen + core polysaccharide + lipid A X - eXtremely heat stable I- IL-1 and IL-6 N- neutrophil chemotaxis S- Shock |
| Scarlet Fever is caused by which bacteria exotoxin? | S. pyogenes |
| Gram positive Aerobic Bacilli: | LIsteria, Bacilus, and Corynebacterium |
| Clostridium is an important represent of: | Anaerobic Gram positive bacili |
| Nocardia is: | Aerobic gram positive branching filamentous bacteria |
| Which is the most common Gram (+) branching filament anaerobic bacteria? | Actinomyces |
| Which bacteria have NOVOBIOCIN sensitivity testing? | S. saprophyticus and S. epidermidis |
| Which specie of Staphylococcus is Novobiocin positive? | S. epidermidis |
| Group A strepto: | S. pyogenes |
| What is the MC representant of Group B strep bacteria? | S. agalactiae |
| Which are the 2 most common representations of Viridans streptococci? | S. mutans and S. mitis |
| Viridans streptococci has no_____________. | Capsule |
| Which streptococci categorie has Optochin testing? | Partial hemolytic streptococcus |
| S. pneumonia is Opsonin ____ or positive. | Sensitive |
| What type of sensitivity is used in Group A and Group B streptococci? | Bacitracin sensitivity |
Created by:
rakomi
Popular USMLE sets