Bacteriology – Flashcards

113 test answers

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Phenolic compounds
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affect lipid-rich plasma membranes, so the cell leaks its contents (especially useful against mycobacteria)
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Phenol coefficient
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ratio of antimicrobial activity compared to pure phenol. smaller means more active
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alcohols
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denatures proteins and dissolves lipids which disrupts membranes
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quaternary ammonium compounds
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decreases surface tension and thereby attacks plasma membranes
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ethylene oxide
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replaces protein functional groups with alkyl groups
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aldehydes
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cross link functional groups of proteins
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iodine
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halogen. interacts with amino acids and proteins
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chlorine
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halogen. oxidizing agent. damages cellular enzymes
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ozone
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oxidizing agent. used for drinking water
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hydrogen peroxide
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oxidizing agent. used by cells to kill bacteria
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Silver, Mercury, Copper
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combine with sulfhydryl groups to denature proteins. very sensitive to organic matter.
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penicillin
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cell wall synthesis inhibitor. has many derivatives
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cephalosporins
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cell wall synthesis inhibitor. 4 generations
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vancomycin
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active against Gram + bacteria. Useful for MRSA and clostridium defficile
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aminoglycosides
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inhibits protein synthesis by insertion of incorrect amino acid
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tetracyclines
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inhibit protein synthesis by blocking A site during translation
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macrolides
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inhibit protein synthesis by inbiting peptidyl transferase and ribosome translocation (50S)
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chloramphenicol
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inhibits protein synthesis by inhibitng peptidyl transferase
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sulfonamides
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developed from pigments. inhibits folate synthesis by inhibiting dyhydropterate synthase
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trimethoprim
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inhibits folate synthesis by inhibiting folate reductase enzyme
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Fluoroquinolones
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inhibit DNA replication by binding to DNA gyrase. example is ciproflaxin
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innate microbial resistance
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microbe lacks the drug target
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acquired microbial resistance
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microbe has undergone a change that compensates for the presence of the drug
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O antigen
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endotoxin/LPS
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K antigen
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capsule/glycocalyx
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H antigen
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flagella
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MacConkey Agar
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contains bile salts and crystal violet so only Enterobacteriaceae can grow on it. contains lactose to differentiate lactose fermenters
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MacConkey Agar
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contains bile salts and crystal violet so only Enterobacteriaceae can grow on it. contains lactose to differentiate lactose fermenters
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Hektoen Enteric Agar
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contains bile salts and iron to detect H2S producing bacteria
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enterotoxigenic E coli (ETEC)
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traveler's diarhea; labile toxin and stabile toxin; treat with fluoroquinolones plus loperamide
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enteropathogenic E coli (EPEC)
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infant diarrhea; plasmid encoded adherence factor causes effacement of microvilli; treat with antibiotics
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enteroaggregative E coli (EAEC)
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persistent diarrhea in undeveloped countries; stacked brick arrangement; treat with fluoroquinolones
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Enterohemorhagic E coli (EHEC)
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O157:H7 most common strain in US; shiga-like toxin; blood in diarrhea; hemolytic uremia caused by damage to kidneys; treat with supportive care
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enteroinvasive E coli (EIEC)
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similar to shigallosis; plasmid encoded invasion genes
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Enteric Fever (Typhoid Fever)
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caused by Salmonella enterica. malaise, headache,rose spots on trunk; bacteria colonizes M cells and then disseminates in blood stream
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Shigella
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Bacillary Dysentery; severe diarrhea containing mucus and blood in feces; pinpoint hemorrhages in cecum; treat with fluid replacement and antibiotics
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Yersinia
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The Plague; zoonotic (urban and sylvatic cycles); spread by fleas; coagulase makes fibrin clot where bacteria can replicate; treat with streptomycin
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Klebsiella pneumoniae
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currant jelly sputum; lung necrosis and abscess; lobar pneumonia; associated with alcoholism; multiple drug resistant
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Klebsiella oxytoca
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colonizes colon and urinary tract; type1 pilli play a role in adherence to uroepithelium; multiple drug resistant
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Proteus mirabilis
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strong urease reaction; swarming motility
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Vibrio cholera
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GI disease or wound infections; oxidase positive (to differentiate from Enterobacteriaceae); serotyped by O antigens; A/B toxin causes tremendous water loss; rice water stool; hypovolemic shock
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Campylobacter
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enteritis/food poisoning; inflammatory diarrhea and pus resulting from prostaglandin function; Guillian Barre Syndrom is a possible complication; get it from poultry or unpasturized milk; microaerophilic and capnophilic
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Helicobacter pylori
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gastic ulcers and gastric cancers; mucinase to penetrate mucous; urease to protect against gastric acidity; oxidative stress resistance; cytotoxin; treat with amoxicillin and clarithromycin
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Pseudomonas aeruginosa
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mostly opportunistic; exotoxin A (ADP ribosyl transferase); Phospholipase C damages membranes; Pyocyanin (blue green pus); Porin makes membranes impermeable to antimicrobials
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Francisella tularensis
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glandular fever, rabbit fever, tick fever; requires cystein for growth; 10 organisms can cause infection; bioterorrism agent
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Brucella
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abortions and reproductive diseases in livestock; undulant fever, mediteranean fever, malta fever; prefers erythritol over glucose
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Haemophils influenzae
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respiratory or systemic infection; type b capsule; capnophilic; requires X factor and V factor; grows on chocolate agar; IgA protease assists in mucosal colonization
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Bordella pertusssis
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whooping cough; catarrhal stage (URT infection), paroxysmal stage (LRT infection), and convalescent stage (neurologic damage); A/B toxin
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Neisseria gonorrhea
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mucous membrane urogenital disease; penicillin resistant and no vaccine; grows on Modified Thayer Agar; oxidase positive
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oxidase test
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assay for cytochrome c oxidase. purple = positive
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Fitz-Hugh-Curtis syndrome
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thinning of cervical mucosa allowing bacteria from vagina into uterus and oviducts; associated with gonorrhea
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Neisseria meningitidis
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mild pharyngitis and mild fever; disseminate; petechial erupton on skin (vasculitic purpura); at blood brain barrier, pilli and endotoxins cause inflammation resulting in entry to CNS; color does not fade when pressed by glass
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Moraxella catarrhalis
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bronchitis and bronchopneumonia; diplococci; normal flora of URT; penicillin resistant
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Bartonella henselae
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cat scratch fever/cellulitis and lymphadenopathy
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Burkholderia
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opportunisitc pathogen of moist environment; B. cepacia (pulmonary infections in cystic fibrosis); B. pseudomallei (pulmonary infection and abscess formation); B. mallei (Glanders)
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Staphylococus aureus
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gold; catalase positive; beta-hemolytic; irregular clusters
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Staph Scalded Skin Syndrome
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Ritter disease (cutaneous blister caused by toxin with no bactera in blister) or Bullous Impetigo (bulb contains bacteria so is communicable)
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Staph Food Poisoning
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salted meats; custard pastries; heat stablic toxin
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Toxic Shock Syndrome
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caused by Staph aureas; tampons; systemic; aerobic atmosphere and neutral pH required; purpura fulminans
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Staph Cutaneous infection
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pyogenic; Imetigo; mascule then pustule, rupture and crusting; MRSA
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Staph pneumonia
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aspiration pneumonia from oral secretions; may cause empyema
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Staphylococcus epidermis
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opportunistic; coagulase negative; non-hemolytic; cutaneous flora; polysaccharide slime for adherence; associated with prosthetic valves
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Staphylococcus saprophyticus
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UTI in newly sexually active women
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Streptococci
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cocci in chains; categorized by surface carbohydrates or by hemolysis type; catalase negative
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Strep pyogenes
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Group A; pharyngitis, scarlet fever, pyoderma(impetigo); erysipelous and cellulitis, necrotizing faciitis; rheumatic fever; acute glomerularnephritis
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Scarlet Fever
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strep throat with toxin production; sandpaper rash; strawberry tongue
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necrotizing faciitis
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flesh-eating bacteria; involves fascia and overlying fat; destroys muscles
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rheumatic fever
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after an untreated case of strep throat; damages heart muscle and valves; mitral stenosis; M protein
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Strep agalactiae
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Group B; vaginal and oral flora; colonization predisposes newborns to respiratory infections, septicemia, and meningitis; early onset (respiratory distress highly fatal) and late onset (meningitis and neurologic damage);. CAMP-positive; hippurate hydrolysis-positive
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Strep pneumoniae
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non-groupable; blood-tinged rusty sputum; COPD and alcoholism are risk factors; alpha hemolytic (green); Quellung reaction positive; Optochin and bile sensitive; vaccinate infants and elderly
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Viridans Endocarditis
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damaged heart; poor oral hygeine or root canal; bind fibronectin
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Viridans Streptococci
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mostly alpha hemolytic; optochin and bile resistant; normal flora of oropharynx, GU and GI tracts
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Streptococcusmutans
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dental plaque; secretes exopolysaccharides; forms a biofilm; acid eats thru enamel and bacteria invade
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Streptococcus bovis
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intestinal tract; colon cancer allows it to translocate to blood stream
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Enterococci
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normal flora; nosocomial infections; catalaste negative; PYR positive; gamma hemolysis; bile esculin positive; resistant to high salt
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Bacillus anthracis
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anthrax; large "box car" rods; zoonotic from ruminants; capsule polypeptide poly-D-glutamic acid; tripartite exotoxin
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cutaneous anthrax
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from contact with infected animals. resolves spontaneously. lesion turns into vesicle filled with blood or clear fluid. dead cells result in necrosis (black eschar) with erythematous raised margin
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Gastrointestinal anthrax
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ingestion of spores in meat. internal lesions
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Inhalation anthrax
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wool sorter's disease; inhalation of spores; alveolar macrophages released in blood stream causes systemic infection with high morbidity
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Tripartide exotoxin
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protective antigen (PA) mediates entry into cells; lethal factor (LF) kills cells; Edema factor (EF) calmodulin activated adenylyl cyclase
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Bacillus cereus
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lacks plasmids that encode virulence; causes gastroenteritis; fried rice; heat-stable enterotoxin causes emetic form; heat-labile enterotoxin causes diarrhea form; Phospholipase C (lecithinase)
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Clostridium perfringens
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soft tissue infections; long rectangular rods; cytolytic toxins; enterotoxin; neuraminidase, collagenase, and proteases; 2 zones of hemolysis on blood agar; alpha toxin test
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Cellulitis
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gas and necrosis in skin
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Faciitis
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suppuratie myositis. pus in planes
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Myonecrosis
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gas gangrene
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Alpha toxin test
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on yolk agar, lecthinase causes precipitate
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Clostridium botulinum
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7 types based on neurotoxin production; food born by consumption of toxin in food; infants get it by consumption of spores in honey; canned food; prevents acetylcholine release resulting in flaccid muscle paralysis
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Clostridium tetani
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lock jaw; prominent terminal spores; blocks release of inhibitory neurotransmitters resulting in continuous muscle contraction; from deep lacerated wounds with low oxygen
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Clostridium difficile
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pseurdomembranous colitis; antibiotics kill normal flora which normally keeps this in check; Toxin A mediates damages mucosa of large bowel; Toxin B hyaluronidase-mediated breakdown of colonic epithelium
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Mycobacteria
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aerobic, acid fast rods; waxy lipids in cell wall provide chemical resistance; Killed by UV filtered by HEPA; Untreated HIV patients with TB
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Mycobacterium tuberculosis
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inhalation into alveoli; pulmonary infection; resolution or walled off in granuloma; granuloma can break down later in life; caseous necrosis; blood-tinged sputum; Lowenstein-Jensen medium
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Mycobacterium leprae
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leprosy/Hansen's disease; unculturable obligate intracellular pathogen; lepromatous form and tuberculoid form
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Mycobacterium avium
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Johne's Disease; chronic diarrhea in cattle; immunocompromised
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Nocardia asteroides
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aerobic; filamentous; branching rods; contracted by inhalation of dust; similar to TB; treat with sulfonamides
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Cornybacterium diptheriae
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Irregular, club shaped; sore throat with pseudomembrane; virulence is through A/B toxin; "bull neck" cervical edema; Elek test
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Listeria monocytogenes
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psychrophile; catalase positive; tumbling motility; food-born pathogen; soft cheeses and undercooked meat; pregnant women and transplant patients at greater risk
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Rickettsia ricketsii
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Rocky Mtn Spotted Fever; vector is hard tick Dermacentor; Maculopapular rash progresses to purpural rash and shock. treat with doxycycline
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Ricksettia prowazekii
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Typhus; body louse is vector; Recrudescent is gradual onset - Brill-Zinsser disease; Sporadic typhus from flying squirrels
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Ehrlichia chaffeensis
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white tailed deer; transmitted by lone star ticks; replicate in phagocytes
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Coxiella burnetii
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multiply in phagosomes; livestock reservoir; antigenic variation (phase I antigen infections, phase II antigen not); Q-fever
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Chlamydiaceae
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intracellular; lack ATP and peptidoglycan; elementary body is infections, reticulate body is metabolically active
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Chlamydia trachomatis
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most common bacterial STD; grows in non-ciliated epithelial cells of GU tract, respiratory tract, and conjuctiva
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Trachoma
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rough eye, Egyptian opthalmia; sensation of granules in the eye
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Mycoplasma/Ureaplasma
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smallest free living bacteria; no cell walls; cell membranes contain sterols; fried egg appearance
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Mycoplasma pneumoniae
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walking pneumonia; binds respiratory epithelium via P1 adhesin; inhibits cilia; superantigen
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Spirochetes
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helical shape with axial filament; 2 cell membranes with LPS-like substance; does not stain with Giemsa or Gram
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Treponema pallidum
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Syphilis; microaerophilic
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Primary Syphilis
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chancre at site of inoculation; pailess; contagious
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Secondary Syphilis
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Flu-like symptoms; maculopapular rash all over; hair loss; wart-like condylomata lata
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Tertiary Syphilis
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Granulomatous lesions of bone, skin, etc. Aortitis; CNS inflammation; blindness
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Borelia burgdorferi
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Lyme Disease; erythema migrans; virulence due to formatio of immune complexes; mice and deer; tick vector
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Borrelia recurrentis
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Relapsing Fever; louse and tick vectors
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Leptospira interrogans
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hooked ends; aerobes; transmissio in animal urine or infected water; flu-like symptoms
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