Term
| Staphylococcal Infections |
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Definition
gram positive cocci, catalase positive, facultative anaerobes
mostly S. areus (coagulase positive + pathogenic), S. epidermis (coagulase negative + less pathogenic)
pathogenic - produce slime to form biofilms (inhibits neutrophil chemotaxis and phagocytosis)
many resistant strains |
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Term
| Localized abscess and boils |
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Definition
caused by S. aureus - infecting cut or hair follicle
coagulase forms fibrin wall
can liquefy and spread |
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Term
| Toxic Shock Syndrom (TSS) |
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Definition
caused by S. aureus that release TSST-1
symptoms caused by body's response to superantigens
overproduction of cytokines - shock, circulatory collapse, multi-organ failure
symptoms: low blood pressure, fever, diarrhea, skin rash, skin shedding |
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Term
| Staphylococcal Scalded Skin Syndrome (SSS) |
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Definition
caused by S. aureus with plasmid-borne gene for exfoliatin (exfoliative toxin)
superantigen that also cleaves skin cell adhesion molecules (protease)
results in blisters
diagnosis: isolation/identification, coagulase+catalase test, serology, DNA fingerprinting, phage typing
treatment: antibiotic therapy (Vancomycin, cephalosporin) |
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Term
| Invasive Streptococcus A infections |
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Definition
caused by S. pyogenes - often leads to sequelae
virulence due to SpeA - superantigen that causes non-specific T-cell activation
rapid tissue loss
exotoxin B (protease) breaks down host proteins
treatment: surgical removal of affected areas, penicillin G |
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Term
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Definition
destruction of sheath covering skeletal muscle
treatment: rapid, agressive antibiotic therapy |
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Term
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Definition
| destruction/inflammation of skeletal muscle and fat tissue |
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Term
| Toxic Shock-like Syndrome (TSLS) |
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Definition
caused by Streptococcus
symptoms: drop in blood-pressure, multi-organ failure, high fever |
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Term
| Gas Gangrene/Clostridial Myonecrosis |
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Definition
caused by clostridium perfringens - gram positive, spore
necrotizing infection of skeletal muscle, produces H2
secretes a-toxin (lecithinase) - membrane damage, cell death, gas tissues, ruptures red blood cells
produces collagenase
spores from soil, bowel microbiota, infected tissues
symptoms: pain, edema, drainage, muscle necrosis
diagnosis: recovery of species, disease symptoms
treatment: surgical debridement (removal of dead tissue), antitoxin, antibiotic therapy, hyperbaric oxygen (increase O2 in blood) |
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Term
| Chickenpox (varicella) and Shingles (Herpes zoster) |
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Definition
caused by varicella-zoster virus - dsDNA, envelope, icosahedral capsule
usually young children (2-7)
human reservoir
replication in lymph nodes, enters bloodstream (primary viremia), replication in liver/spleen, second viremia, moves to epidermis (vesicular rash)
varicella vaccine
treatment: acyclovir - inhibits viral DNA polymerase
Shingles: occurs after Chickenpox (latent)
migrates down nerve axon, replication, damage to sensory neurons
vesicles along dorsal trunk |
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Term
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Definition
caused by variola major (life-threatening) + minor (minor infection)
remember Jenner + cowpox
Prodomal stage: symptomatic, infects epithelial cells in mouth+throat, head/body aches, fever
infects capillary epithelia of skin - vesicles/skin lesions
Eradication: achieved through vaccination, no asymptomatic carriers, humans are the only reservoir, short infectivity period |
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Term
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Definition
caused by Streptococcus pneumonidae - opportunistic, usually in upper respiratory tract, polysaccharide capsule prevent phagocytosis
common among AIDS patients
symptoms: chills, laboured breathing, chest pain, rust-coloured sputum, high fever
diagnosis: chest X-ray, gram stain culture, elevated WBC (indicates bacterial vs. viral)
treatment: penicillin G, Pneumovax vaccing (protects again 23 antigens)
resistance against antibiotics is increasing |
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Term
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Definition
caused by Mycobacterium tuberculosis - gram positive, identified by Koch
mycolic acids in cell wall (hydrophobic barrier) prevents phagocytic killing
transmitted from person to person
tubercules (infected nodules) form in alveolar lymphatic nodes - contain bacteria, macrophages, T cells, human proteins
tubercules, caseous lesions, Ghon complex (calcified)
miliary tuberculosis: tubercules liquefy and bacteria spread, wide dissemination, small lesion
diagnosis: develop immunity/sensitized T cells - tuberculin skin test, acid-fast bacteria, chest X-ray
symptoms: fever, fatigue, weight loss, cough, bloody sputum
treatment: MDR-TB, antimicrobial therapy, rapid, specify therapy, immunization |
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Term
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Definition
caused by influenza virus - categorized by hemaglutinin - binding to host+entry (HA) and neuraminidase - release of progeny (NA)
HA/NA recombine to form subtypes
symptoms: chills, fever, headache, muscle ache, painful joints, fast recovery, sometimes secondary infections
treatment: immunologic tests for subtype, symptomatic/supportive therapy, Tamiflu vaccine - neuraminidase inhibitor (shortens illness) |
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Term
| Enterohemorrhagic E. coli infection |
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Definition
caused by EHEC strain O157:H7
destruction of mucosal epithelium, inflammation + Shiga toxin, production of blood + leukocytes in stools
Shiga toxin cleaves 28S rRNA - platelet-fibrin micro-clots forms - kidney failure (HUS), skin hemorrhage, brain hemorrhage, coma, death
symptoms: diarrhea, abdominal cramps
diagnosis: positive test for EHEC in food/patient, positive testing for toxin
treatment: no cidal antibiotics (antimicrobial treatment can increase toxin release), statics, supportive treatment (dialysis, blood transfusions) |
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Term
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Definition
caused by Helocobacter pylori - gram negative, produces urease (increase pH)
releases toxin that damages epithelial mucosal cells
person to person transmission
diagnosis: culture of gastric biopsy specimens, examination of stained biopsies, urease activity in biopsies
treatment: drugs to decrease stomach acid + antibiotics to kill bacteria |
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Term
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Definition
caused by rotavirus
symptoms: inflamed stomach+intestines, diarrhea, nausea, vomiting, abdominal cramping, dehydration + electrolyte loss
children are most severely affected
no cure
treatment: replace electrolytes - isotonic solutions, rehydration |
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