Bacteriology – Flashcards
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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 |
