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
GramPosBacteria
lecture 5 greenberg
| Question | Answer |
|---|---|
| carbuncle | lateral and deep extension of S. aureus; several coalesced furuncles with several openings to the surface with discharging pus |
| abscess | central area of necrosis, infection with dead host cells and bacteria surrounded by reactive fibrosis |
| empyema | infection of thoracic cavity external to lung |
| erysipelas | infection of superficial skin with marked involvement of lymphatic vessels |
| exfoliatin | EC product of S. aureus responsible for intradermal splitting and necrosis seen with scalded skin syndrome (SSS) |
| furuncle | small abscess or boil; painful, indurated, erythematous and caused by S. aureus |
| impetigo | infection of the superficial layers of skin - epidermis and outer dermis |
| leucocidin | exotoxin of S. aureus that destroys PMN leukocytes (specifically Panton-Valentine leukocidin) |
| puerperal sepsis | bacteremia in mother following childbirth |
| shock | syndrome characterized by hypotension from systemic vasodilation |
| likely function of coagulase in S. aureus | makes it an invasive organism; allows it to wall off infection and stop blood supply thus inhibiting leukocyte entry into wound |
| function of protein A in S. aureus | bings IgG's Fc portion, allows bacteria to evade immune cells labeling it for phagocytosis |
| Name another Staphylococcus besides aureus that's resistant to methicillin | up to 98% of S. epidermidis and other coag neg spp. |
| Staphylococcus saprophyticus | the only coag neg Staphylococcus that is resistant to novobiocin disc on agar plates; causes 20-30% of symptomatic UTIs in young, sexually active females |
| L-pyrrolidonyl arylamidase (PYR) | diagnostic enzyme for Group A beta hemolytic strep (S. pyogenes) |
| important diagnostic tool to distinguish beta hemolytic strep bacteria apart | bacitracin resistance |
| M protein | major virulence factor within Streptococcus pyogenes; is antiphagocytic and allows them to bind to epithelial cells & keratinocytes; ~ 100 diff serotypes identified by M protein DNA sequencing |
| hyaluronate capsule | typical of group A beta hemolytic strep, barrier to complement components and binds CD44 on host tissues |
| methods of virulence for GABHS | M protein, EC matrix binding protein, hyaluronic acid capsule, Ig-binding protein, C5a peptidase, streptolysins, DNAases acting on lysed cells in pus, streptokinase, superantigens |
| streptokinase | GABHS - degrades clots by activating host plasminogens and allowing spread in tissues |
| name of GABHS proteases that degrade host and bacterial tissues | SpeA, -B and -C proteases |
| 2 important immune-mediated conditions caused by GABHS infection | acute post-streptococcal glomerulonephritis acute rheumatic fever |
| tonsillopharyngitis/strep throat - mainly caused by this bacterial group | GABHS (sometimes groups C or G) |
| differences btwn TSS by S. aureus and GABHS | S. aureus - inapparent site of infection, lacks bacteremia and low fatality rate |
| description/mechanism of acute rheumatic fever | occurs 7-21 days post-strep infection of the PHARYNX; thought to be a cross-rxn to antibodies initially produced against Strep, affects heart and other tissues |
| signs of acute rheumatic fever | heart inflammation producing arrhythmias, polyarthritis, fever, skin abnormalities, choreiform movements |
| description/mechanism of acute poststreptococcal glomerulonephritis | occurs 7-21 days post-strep infection of either skin or pharynx; immune complexes to Strep antigens are deposited in glomerular subepithelium |
| signs of acute poststreptococcal glomerulonephritis | from simple proteinuria or microscopic hematuria to complete renal failure then death |
| mechanism of puerperal sepsis | GABHS (or GBBHMS) travel up vagina, invades endometrium and uterine lymphatics to cause bacteremia |
| the major virulence factor associated with GBBHS | type III capsule, allowing evasion of phagocytosis |
| abx of preference for treating GBBHS | PCN or ampicillin |
| environmental niche of GBBHS | vagina - causes many OB and neonatal infections |
| most prevalent causative agent of CAP | Streptococcus pneumoniae |
| niche of Strep pneumo | upper resp tract/oropharynx |
| 2 main spots Strep pneumoniae has specific adhesion factors for | NAG and 3-Gal disaccharides on epithelial cells; PAF in the plasma |
| phase variation - definition and example of bacteria that exhibits it | ability to up or downregulate adhesion factors in the cell wall according to the site of attachment or infection; pneumococci |
| 3 abx of choice for pneumococcal infection | PCN G, vanc and Rocephin |
| features on would look for when Gram-staining sputum for pneumococcal infection | GP, lancet or football-shaped diplococci, optochin-sensitive, alpha hemolytic |
| drug of choice to treat VRE | ampicillin |
| special features typical for growing Enterococcus | grow in presence of bile and 6.5% NaCl |
| niche of viridans Streptococci like species mutans, sanguis and salivarius | mouth, on surface of teeth and gums |
| name diseases from toxins of Clostridia: difficile, tetani, botulinum, perfringens | C-diff diarrhea (nosocomial usually) tetanus - spastic neurological dz perfringens - gas gangrene, necrotizing skin infections botulism - paralyzing neurological dz |
| name diseases from toxins of Bacillus genus: cereus and anthracis | anthrax - non-hemolytic type food-borne diarrhea, is hemolytic |
| 2 most medically important non spore-forming GP rods | Corynebacterium and Listeria (both are non-filamentous also) |
| the most likely people to be affected by anthrax spores | abbatoir or slaughterhouse workers who are exposed to the hides or meat of animals who were previously infected |
| 3 clinical syndromes that could result from anthrax spore intoxication | cutaneous - from open wounds, trauma GI - from eating contaminated meat inhalational - from inhaling aerosolized spores |
| 3 virulence factors of Bacillus anthracis | edema toxin, lethal toxin and protective antigen |
| B. anthracis virulence factors are A-B toxins | protective antigen - B edema and lethal factor - A (EF = calmodulin-dependent adenylate cyclase = anti-inflammatory cytokines; LF = MAPK kinase that stops cell growth) |
| best abx to treat B. anthracis | doxycycline and cipro (if naturally occuring, PCN hopefully) |
| pneumococcus vaccines | 13-valent polysaccharide version for children 23-valent " " " adults |
| 2 types of illneses produced from B. cereus intoxication | emetic and diarrheal illness |
| Contrast the 2 syndromes from B. cereus intoxication | emetic - from heat-stable endotoxin, improperly heated fried rice, sx within 1-6 hours diarrheal - heat-labile endotoxin, from ingesting spores in cream sauce, vegetative cells germinate in gut, sx in 12-24 hrs |
| Clostridium species/type associated with gas gangrene | perfringens type A (a in both gas and gangrene) |
| Clostridium species/type associated with necrotizing enterocolitis | perfringens type C (C in colitis) |
| How does C. perfringens gain access to soft tissues and skin? | usually through trauma/dirty wounds where clostridia were in soil or feces and contacted wound |
| T/F Inflammatory cells are usually intermixed with C. perfringens when looking at gas gangrene tissue histologically. | no, they release toxins to lyse WBCs = no inflammatory cells |
| method of contracting C. perfringens gastroenteritis/specific pathogenic substance | ingesting meat that was stored at high temps allows spores to germinate and release heat-labile enterotoxin once in the body |
| mechanism of action of C. difficile toxins | toxins A/B - combo of enterotoxin that causes massive fluid secretion and cytotoxin that causes death and sloughing of intestinal epithelium |
| possible deadly outcome of C. difficile diarrhea | toxic megacolon |
| abx of choice to kill any remaining C. tetani bacteria at site of infection in tetanus pt | metronidazole (NOT!! PCN) |
| functions of the two chain toxin of C. tetani | heavy - specific binding to GABA-containing inhibitory nerves light - endopeptidase that cleaves synaptobrevin = no vesicle release |
| neurotoxin that causes tetanus | tetanospasmin |
| mechanism of C. botulinum toxin | has light chain endopeptidase that prevents ACh release from NMJ = flaccid paralysis |
| most typical circumstance in which person comes into contact with C. botulinum | home canned products, eating food that wasn't cooked well enough and heat-labile toxin persists |
| why no raw honey to infants? | infant botulism from possible clostridial spores in honey |
| tx for tetanus | equine antitoxin |
| how C. diphtheriae become virulent | by acquiring the diphtheria toxin from a lysogenic phage |
| niche of C. diphtheriae | resp tract and skin |
| mechanism of A-B toxin of diphtheroids | B binds cell surface, A ADP-ribosylates EF-2 (elongation-factor 2) effectively stopping eukaryotic protein synthesis |
| vaccines available? tetanus, botulism, diphtheria, C. difficile infection | tetanus - yes botulism - no diphtheria - yes C. diff - no |
| cause of death from diphtheria | toxin-induced cell death of throat epithelium, formation of pseudomembranes, obstruction of throat and resp failure from inability to get air or diaphragm paralysis |
| primary route of infection of Listeria | fecal-contaminated foods like milk or queso fresco, even when properly refrigerated |
| abx of choice for Listeria | ampicillin, possibly also Bactrim for some isolates |
| Listeria's preferred method for growing in host | intracellularly, induces phagocytosis then escapes into cytoplasm to replicate |
| tests to differentiate btwn Listeria and Streptococci | Listeria - catalase +, beta-hemolytic Streptococci - catalase -, all types of hemolysis |
| erysipelothrix | caused by Erysipelothrix rhusiopathiae - erysipelas-like rash on hands of fisherman/abattoirs |
| causes severe acne | Propionibacterium acnes |
| diseases caused by Listeria monocytogenes | meningitis or bacteremia in immunocompromised and neonates, most typically though self-limited diarrheal illness |
| psychrophilic | able to live in refrigerator temps |
Created by:
sirprakes
Popular Bacteriology sets