Bacteria categories Flashcards
Gram + cocci
Staphylococcus
Streptococcus
Enterococcus
Gram - cocci
Moraxella catarrhalis
Neisseria
Gram + rod (bacillus)
Lactobacillus Bacillus Listeria Clostridium Mycobacterium (acid fast) Corynebacterium Gardnerella (gram variables) Cutibacterium (formerly Propionibacterium)
Gram - rod (enterics)
Bacteroides Campylobacter E coli Enterobacter Fusobacterium Helicobacter Klebsiella Proteus Pseudomonas Salmonella Serratia Shigella Vibrio Yersinia
Gram - rods (respiratory)
Acinetobacter baumannii Bordetella Burkholderia cepacia Haemophilus (pleiomorphic) Legionella (silver stain)
Gram - rods (zoonotic)
Bartonella
Brucella
Francisella
Pasteurella
Branching filamentous, gram positive
Actinomyces
Nocardia (weakly acid fast)
Pleomorphic (no cell wall)
**ALL GRAM NEG/DO NOT STAIN** Anaplasma Ehrlichia Chlamydiae (Giemsa) Rickettsiae (Giemsa) Mycoplasma (contains sterols, which do not Gram stain) Ureaplasma
Spiral
Spirochetes!
Borrelia (Giemsa)
Leptospira
Treponema
Which bugs stain with Giemsa?
Rickettsia Chlamydia Trypanosomes Plasmodium Borrelia
Which bug stains with PAS?
Whipple (Tropheryma whipplei)
Which bug stains with Ziehl-Neelsen stain?
Acid-fast bacteria (Mycobacteria, Nocardia), protozoa (Cryptospiridium oocysts)
Which bug stains with India ink?
Cryptococcus neoformans
Which bugs stain with silver stain?
Fungi (eg Coccidioides, Pneumocystis jirovecii)
Legionella
H pylori
What grows on chocolate agar?
H flu
What grows on Thayer-Martin agar?
N gonorrhea, N meningitidis
What grows on Bordet-Gengou agar?
B pertussis
What grows on Tellurite agar?
C Ddiptheriae
What grows on Lowenstein-Jensen agar?
M tuberculosis
What grows on Eaton agar?
M pneumoniae
What grows on MacConkey agar?
Lactose-fermenting enterics (fermentation produces acid, causing colonies to turn pink)
What grows on eosin-methylene blue (EMB) agar?
E coli (colonies with green metallic shine)
What are the most common anaerobes?
Clostridium
Bacteroides
Fusobacterium
Actinomyces israelii
Which bugs are obligate intracellular?
Rickettsia
Chlamydia
Coxiella
(Rely on host ATP)
Which bugs are facultative intracellular?
Salmonella Neisseria Brucella Mycobacterium Listeria Francisella Legionella Yersinia pestis
Which bugs are encapsulated?
Pseudomonas Strep pneumo H flu Neisseria meningitidis E coli Salmonella Klebsiella Group B strep
Which are the urease positive organisms?
Proteus Cryptococcus H pylori Ureaplasma Nocardia Klebsiella S epidermidis S saprophyticus
What does it mean to be catalase psotivie?
Catalase degrades H2O2 into H2O and bubbles of O2 before it can be converted to microbicidal products by the enzyme myeloperoxidase
People with chronic granulomatous disease have recurrent infections with certain catalase positive organisms
What is Protein A and who expresses it?
Protein A binds Fc region of IgG, preventing opsonization and phagocytosis
Expressed by S aureus
What is IgA protease and who expresses it?
Enzyme that cleaves IgA, allowing bacteria to adhere to and colonize mucous membranes
Secreted by S pneumo, H flu, and Neisseria
What is M protein and who expresses it?
Helps prevent phagocytosis. Expressed by group A strep. Shares similar epitopes to human cellular proteins (molecular mimicry); possibly underlies the autoimmune response seen in acute rheumatic fever
Which bacteria form spores?
Bacillus anthracis Bacillus cereus Clostridium botulinum Clostridium difficile Clostridium perfringens Clostridium tetani
Inactive elongation factor (EF-2)
C diphtheriae (Diphtheria toxin) Pseudomonas (Exotoxin A)
Inactivate 60s ribosome by removing adenine from rRNA
Shigella (Shiga toxin)
Enterohemorrhagic E coli (Shiga-like toxin)
What is the difference between Shiga toxin and Shiga-like toxin?
Shigella causes GI mucosal damage leading to dysentery; ST also enhances cytokine release, causing HUS
In contrast, SLT enhances cytokine release but does not invade the host cells
Overactivates adenylate cyclase (increasing cAMP), causing increased Cl- secretion in gut and H2O efflux
Enterotoxigenic E coli (heat-labile toxin)
Overactivates guanylate cyclase (increasing cGMP), causing decreased NaCl and H2O resorption in gut
Enterotoxigenic E coli (heat-stable toxin)
Mimics adenylate cyclase (increasing cAMP)
Bacillus anthracis (edema toxin)
Overactivates adenylate cyclase (increasing cAMP) by permanently activating Gs leading to increased Cl- secretion in gut and H2O efflux
Vibrio cholerae (Cholera toxin)
Overactivates adenylate cyclase (increasing cAMP) by disabling Gi, impairing phagocytosis to permit survival of microbe
Bordetella pertussis (Pertussis toxin)
Proteases that cleave SNARE, a set of proteins required for neurotransmitter release via vesicular fusion
Clostridium tetani (Tetanospasmin): toxin prevents release of inhibitory (GABA and glycine) neurotransmitters from Renshaw cells in spinal cord, leading to spastic paralysis, risus sardonicus, trismus (lockjaw) Clostridium botulinum (Botulinum toxin): toxin prevents release of stimulatory (ACh) signals at neuromuscular junction, leading to flaccid paralysis
Phospholipase that degrades tissue and cell membranes
Clostridium perfringens (Alpha toxin)
Protein that degrades cell membrane
Streptococcus pyogenes (Streptolysin O)
Cross-links beta region of TCR to MHC Class II on APCs outside of the antigen binding site, leading to oerwhelming rlease of IL-1, IL-2, IFN,gamma, and TNF-a, leading to shock
Streptococcus pyogenes (Erythrogenic exotoxin A) Toxic shock-like syndrome: fever, rash, shock; sclarlet fever
Which bug is coag+ and novobiocin sensitive?
Staph epi
Which bug is coag+ and resistant to novobiocin?
Staph saprophyticus
Which bug has alpha hemolysis?
Alpha = green, partial hemolysis
Strep pneumo and Strep viridans
Which bug is optochin sensitive? Optochin resistant?
Optochin sensitive: S pneumo
Optochin resistant: Strep viridans
Which bug has beta hemolysis?
Beta hemolysis = complete hemolysis, clear
Strep pyogenes
Strep agalactiae
Which bug is bacitracin sensitive? Bacitracin resistant?
Bacitracin sensitive: S pyogenes
Bacitracin resistant: Group B strep agalactiae
Which bug has gamma hemolysis?
Gamma hemolysis = no hemolysis
S bovis
Enterococcus (E faecium, E faecalis)
What does actinomyces cause?
Causal oral/facial abscesses that drain through the sinus tracts; often associated with dental caries/extraction and other maxillofacial trauma
forms yellow “sulfur granules”
can also cause PIDs with IUDs
