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Bacteria Cards
Question | Answer |
---|---|
Lipopolysaccharide | G (-) surface antigen endotoxin. Lipid A -> TNF & IL-1 induction |
Bacterial ribosome | 50s & 30s |
Gram + Organism Characteristics | Teichoic acid |
Gram – Organism Characteristics | Endotoxin/LPS, Periplasmic space |
Non- Gram Stain Organisms | Treponema (too thin, fluorescent antibody stain), Rickettsia (intracellular), Mycobacteria (acid fast +), Mycoplasma (no cell wall), Leigonella (intracellular- Silver stain +), Chlamydia (intracellular) |
Exotoxins | Select G+ & - bacteria. Secreted polypeptide encoded on a plasmid, uber-toxic. Induces strong antibody response. Heat labile (-staph enterotox). Examples: Tetanus, botulism, diphtheria. |
Exotoxin-Secreting Bugs | S. aureus:TSST-1; S. pyogenes:Scarlet fever&erythyrogenic toxin; c. Perifringens:gas gangrene&double hemolysis, Tetani:blocks GABA; Botulinum:blocks ACh; Anthrax:adenylate cyclase; Shigella:Shigga cleaves host rRNA, HUS; s Pyogenes:Streptolysin-hemolysis |
Endotoxins | Most G- & listeria. Endemic surface lipopolysaccharide. Less toxic, less antigenic. Induces TNF & IL-1 -> fever, shock. Heat stable. Examples: Meningococcemia, G- sepsis. |
Protein A | Binds Fc region of Ig. s aureus. |
IgA protease | Secreted from encapsulated orgs: s. pneumo, h. flu, neisseria. |
GAS M Protein | Blocks phagocytosis |
Conjugation | F plasmid contains conjugation genes. Hfr cells incorporate into DNA and can transmit adjacent DNA. |
Transformation | DNA uptake from environment |
Transduction | Generalized: LYTIC phage lyses host DNA & some host DNA can get into viral capsid. Specialized: Host DNA on either side of integrated viral genome is taken & packaged into LYSOGENIC phage viral capsid. |
Transposition | Transposons that carry genes for virulence & antibiotic resistance. Insert into plasmids, bacterial chromosomes |
Toxins encoded in lysogenic phages | (ABCDE) shigA-like toxin, Botulinum, Cholera, Diptheria, Erythrogenic toxin of s. pyogenes |
Obligate Aerobes | Nocardia, p. aeruginosa, TB, Bacillus. |
Obligate Anaerobes | Actinomycetes, bacteroides, clostridium. |
Facultative Intracellular Organisms | Salmonella, neisseria, brucella, mycobacterium, listeria, francisella, legionella, yersinia |
Obligate Intracellular Organisms | Rickettsia, Chlamydia |
Encapsulated Bacteria | Strep pneumo, h flu, neisseria meningitidis, klebsiella |
Spore formers | bacillus (antracis, cereus), clostridium (botulinum, diff, perifringens, tetani) |
Urease + Orgs | H pylori, proteus, klebsiella, ureaplasma |
Gram (-) & Penicillin | resistant to benzylpenicillin G, +/- susceptible to derivatives (ampicillin). Outer membrane --| Penicillin G & Vanco entry |
Enterobacteriaceae Characteristics | (e coli, salmonella, shigella, klebsiella, enterobacter, serratia, proteus). All have O-antigen (endotoxin), glucose fermenter, oxidase (-). Capsular K antigen determines virulence. Flagellar H antigen on motile species. |
Lactose Fermenting Enterocytes | Pink on MacConKEE agar: Klebsiella, E coli, enterobacter, Citrobacter. |
Vibrio parahaemolyticus & vulnificus | Seafood contamination. V. vulnificus -> wound infx contaminated w/shellfish or water. |
Food Poisoning Organisms | Vibrio, Bacillus cereus, S. aureus, clostridium perifringens, c botulinum, e coli, salmonella |
Bloody Diarrhea Organisms | Campy, salmonella, shigella, enterohemorrhagic & enteroinvasive e. coli, yersinia, c diff, entamoeba histolytica. |
Watery Diarrhea Organisms | Enterotoxigenic e. coli, cholera, c. perifringens, protozoa (giardia, cryptosporidium), viruses (rota, adeno, noro-viruses) |
cAMP Inducers | cholera, pertussis, e coli heat-labile toxin, anthrax (primary adenylate cyclase, -|PMNs + Edema) |
Zoonotic Bacteria | Bartonella henselae, borrelia burgdorferi, brucella, francisella, yersinia, pasturella. |
Bartonella henselae | cat scratch fever, by cat scratch |
Borrelia burgdorferi | Lyme disdease, ixodes ticks on deer & mice |
Gardnerella vaginalis | +/- gram staining rod. Non-painful white/gray fishy vaginal discharge. Coinfx w/ Mobiluncus (anaerobe). Dx: Clue cells, epithelial cells covered in bacteria. Treatment: Metronidazole. |
Giemsa’s Stain | Borrelia, Plasmodium, Trypanosomes, Chlamydia |
PAS Stain (periodic acid-Schiff) | Whipple’s Disease. Stains glycogen & mucopolysaccharides. |
Ziehl-Neelsen Stain | Acid-fast bacteria |
India ink | Cryptococcus neoformans |
Silver Stain | Fungi, Leigonella |
Chocolate agar | H flu: Factor V (NAD) & X (hematin) |
Thayer-Martin Media | N. gonorrhoeae |
Bordet-Gengou Agar | Pertussis. Potato-based agar. |
Tellurite Plate, Loeffler Medium | Corynebacterium Diptheriae -> black colony |
Lowenstein-Jensen Agar | TB |
MacConkey’s Agar | Lactose fermenting enteric bacteria -> Pink (Kleb, E coli , Entero > Citro, Serratia) |
Charcoal Yeast Extract | Leigonella, buffered with iron & cysteine |
Sbouraud’s Agar | Fungi |
E Coli Enteritis Subtypes & Toxins | ETEC:Heat labile & stable tox -> travelers diarrhea; EHEC: Shigga-> bloody diarrhea & HUS, EIEC: Bloody diarrhea. LT: AB toxin -> ADP ribosylatoin Gs-> cAMP -> Diarrhea. |
A-B/ADP Ribosylating Toxin Bugs | PERTUSSIS--|Gi--|chemokines & phagocytosis. Pseudamonas & DIPTHERIA --|EF2. E COLI & CHOLERA->Gs->uber diarrhea |
Bacteriostatic Antibiotics | Erythro- & Clindamycins, SMX, Trimethoprim, Tetracyclines, Chloramphenicol |
Bactericidal Antibiotics | Vancomycin, Fluoroquinolones, Penicillin, Aminoglycosides(-mycins), Cephalosporins, Metronidazole |
Sulfa Allergies | Sulfonamides, sulfasalazine, sulfonylureas, thiazides, acetazolamide, furosemide |
VRE Treatment | Linezolid & streptogramins (-pristins) |
Contraindicated Antibiotics in Pregnancy | Sulfonamides (kernicterus), Aminoglycosides (ototoxicity), Fluoroquinolones- cartilage, Erythromycin-cholestatic hep, Metronidazole: mutations, Tetracyclines: teeth, inhibit bone growth, Griseofulvin: teratogenic. Chloramphenicol: gray baby. |
1st Gen Cephalosporins | Cefazolin, Cephalexin |
2nd Gen Cephalosporins | Cef -oxitin, -uroxime, -clor |
3rd Gen Cephalosporins | Cef -tazidime, -triaxone, -ixime |
4th Gen Cephalosporin | Cefepime |