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122 Cards in this Set
- Front
- Back
Streptococcus pyogenes
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-- gram-positive -- beta-hemolytic -- catalase negative |
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Streptococcus pyogenes: Reservoir
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-- human throat -- skin |
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Streptococcus pyogenes: transmission
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-- direct contact -- respiratory droplet |
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Streptococcus pyogenes: toxins
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-- streptolysin O: hemolysin, immunogenic -- exotoxins: cause fever, rash -- super antigen: mobilizes T cells |
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Streptococcus pyogenes: diseases
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-- pharyngitis--> sore throat -- scarlet fever--> sore throat fever, "sandpaper rash", strawberry tongue -- pyoderma--> skin infection: honey-crusted leisions |
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Streptococcus pyogenes: sequelae/complications
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-- rheumatic fever--> antibodies and damage to the heart tissue, damage to the joints/inflammation -- acute glomerulonephritis--> immune complexes (antigen-antibody) in glomeruli, fluid in the lungs, "smoky" urine due to protein loss |
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Streptococcus agalactiae: reservoir
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-- birth canal -- GI tract |
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Streptococcus agalactiae: transmission
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-- newborn infected during birth
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Streptococcus agalactiae: diseases
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-- nenonatal meningitis -- septicemia (massive blood infection) |
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Streptococcus agalactiae: prevention
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-- antibiotic before delivery
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Streptococcus pneumoniae: reservoir
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-- respiratory tract
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Streptococcus pneumoniae: transmission |
-- respiratory droplets
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Streptococcus pneumoniae: predisposing factors
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-- influenza -- COPD, CHF -- alcoholism |
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Streptococcus pneumoniae capsule
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prevents detection by immune system
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Streptococcus pneumoniae: toxin
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-- pneumolysin--> damages epithelium
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Streptococcus pneumoniae: diseases
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-- pneumonia--> chills, fever, lobar consolidation, rusty sputum (liquid coughed-up) -- meningitis -- otitis media--> inflammation of the middle ear |
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Streptococcus pneumoniae: vaccine
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--avaliable -- pediatric: 7 serotypes -- adult: 23 common serotypes |
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Bacillus
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-- gram-positive -- spore forming -- rod shaped |
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Bacillus anthracis: reservoir
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-- in soil -- on animal skins |
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Bacillus anthracis: transmission
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-- contact w/ soil, animals -- inhalation of spores |
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Bacillus anthracis: toxins
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-- lethal factor--> kills cell -- edema factor--> swelling |
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Bacillus anthracis: capsule?
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yes
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Bacillus anthracis: diseases
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-- cutaneous anthrax--> skin necorsis -- GI anthrax--> vomiting, diarrhea -- pulmonary anthrax--> pneumonia: cough, fever, dyspnea, shock, death |
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Bacillus cereus: reservoir
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-- found in nature -- food borne (affinity w/ fried rice), in food kept warm |
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Bacillus cereus: toxins
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-- diarrheal toxin--> watery diarrhea -- emetic toxin--> vomiting |
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Bacillus cereus: disease
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-- gastroenteritis
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Clostridium
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-- gram-positive -- spore forming rods -- anaerobic |
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Clostridium tetani: reservoir
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-- found in soil |
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Clostridium tetani: acquired?
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-- trauma -- animal bites |
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Clostridium tetani: toxin
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-- tetanospasmin: travels to CNS, blocks release of GABA and glycine (inhibitory neurotransmitters), causes muscle spasms
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Clostridium tetani: diseases/condition
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-- tetanus: spasms, respiratory arrests
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Clostridium tetani: Rx
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-- spasmolytic drugs -- antibiotics -- prevention: wound care -- vaccine: every 10 years -- boost: every 5 years |
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Clostridium botulinum: reservoir
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-- found in soil, house dust, raw honey
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Clostridium botulinum: acquired?
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-- food borne--> improperly canned foods -- trauma |
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Clostridium botulinum: toxin
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-- botulinum toxin: absorbed from GI tract, blocks release of acetylcholine (neurotransmitter that is used by PNS, CNS)
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Clostridium botulinum: diseases
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-- infants: spores are ingested, toxins produced, causes paralysis -- adults: poorly canned veggies, smoked fish, causes blurred vision, paralysis, nausea, vomiting |
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Clostridium perfringes: reservoir
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-- soil -- human colon |
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Clostridium perfringes: transmission
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-- foodborne -- trauma |
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Clostridium perfringes: toxins
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-- alpha toxin: damages membranes, tissue necrosis -- eneterotoxin: diarrhea, cramps -- + 10 other toxins -- hemolytics |
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Clostridium perfringes: disease
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-- food poisoining: not properly heated meat dishes -- gas gangrene: due to contamination of wound w/ soil -- toxins cause pain, edema, gas -- rapid mortality |
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Neisseria
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-- gram-negative -- diplococci w/ flattened sides -- oxidase positiv |
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Neisseria meningitides (Meningococcus)
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-- large capsule -- grows on chocolate agar with 5% CO2 -- ferments maltose |
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Neisseria meningitides: reservoir
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-- human nasopharyngeal area (nose/throat)
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Neisseria meningitides: transmission
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-- respiratory droplets -- spread to the meninges via the blood stream |
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Neisseria meningitides: virulence factors
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-- polysaccharide capsule -- endotoxin |
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Neisseria meningitides: disease
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-- meningitis: abrupt onset w/ fever and chills, malaise, prostration -- servere cases--> shock, coma, death, Waterhouse-Fredrickson syndrome: necrosis of adrenal glands |
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Neisseria meningitides: prevention
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-- vaccine: capsular polysaccharide of strains Y, W, C, A
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Neisseria gonorrhea (Gonococcus)
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-- no capsule -- does not ferment maltose |
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Neisseria gonorrhea: reservoir
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-- human genital tract (not normal microflora)
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Neisseria gonorrhea: transmission
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-- sexual contact -- birth |
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Neisseria gonorrhea: pathogenesis
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-- pili attachment to mucosal surfaces -- outer-membrane (releases toxin) |
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Neisseria gonorrhea: disease
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-- gonorrhea -- male: urethritis, proctitis -- female: cervicitis, proctitis, PID, arthritis, could be asymptomatic -- newborn: ophthalmia (blindness) |
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Neisseria gonorrhea: prevention
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-- silver nitrate -- erythromycin ointment in the eyes |
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Chlamydia
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-- intracellular organism (does not make its own ATP) -- found in cells in two forms: 1. infective form- inactive elementary body 2. metabollically active forms-replicating reticular bodies |
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Chlamydia: reservoir
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-- can be found in human genital tract -- can infect eyes (different strain) |
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Chlamydia: transmission
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-- sexuall contact -- birth -- trachoma: hands to eyes |
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Chlamydia: mechanism |
-- infects epithelial cells of mucosal surfaces, causes granulomatous inflammation mediated by DHT cells
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Chlamydia: diseases
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-- non-gonococcal urethritis or cervicitis (STD), serotypes D-K, PID -- conjunctivitis -- pneumonia in neonates -- lympogranuloma venereum: lymph nodes, lymphedema, lesions, L serotypes -- trachoma (blindness): serotypes A-C, conjunctiva scarring |
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Treponema pallidum
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-- spriochete -- gram-negative -- outer membrane (lipids A) -- cannot be cultured in lab--> too many nutritional needs |
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Treponema pallidium: reservoir
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-- human genital tract
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Treponema pallidium: transmitted
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-- sexually -- via placenta |
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Treponema pallidium: pathogenesis
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-- endarteritis (infection of the lining of the blood vessels) -- reults in leisions |
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Treponema pallidium: disease
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-- syphilis -- incubation is from 10 to 90 days -- congenital syphillus: commonly in babies of IV drug abusing wommen, still birth, fetal abnormalities, notched teeth, snuffle (spinal fluid leak) |
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Treponema pallidium: primary
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-- non-tender chancer (leisions) -- contagious -- heals spontaneously in 3-6 weeks |
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Treponema pallidium: secondary
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-- 1-3 months later it spreads via blood stream -- rash on skin, palms, and soles -- patchy hair loss |
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Treponema pallidium: tertiary
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-- years later in 1/3 of untreated patients -- gummas, aortitis, CNS inflammation (dementia) |
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Treponema pallidium: diagnosis
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-- visualization: immunofluorescence, dark field microscopy -- serology |
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Mycobacterium
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-- acid fast rods w/ waxy cell wall -- obligate aerobe -- slow growth on Lowensein-Jensen agar -- Auramine-rhodamine staining bacilli -- catalase positive |
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Mycobacterium: cell wall
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-- unique cell wall--> peptides, free lipids (waxes, "cord factor"), mycolic acid, peptidoglycan -- resistant to drying -- resistant to chemicals |
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Mycobacterium: reservoir
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-- human lungs
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Mycobacterium: transmission
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-- respiratory droplets
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Mycobacterium: predisposing factors
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-- poverty -- immunosuppression (cancer, autoimmune diseases, HIV) |
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Mycobacterium: diseases
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-- tuberculosis (TB) -- affects pulmonary system, urinary system |
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Tuberculosis symptoms
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-- nonproductive cough -- low grade fever -- night sweats -- anorexia -- most people heal |
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Tuberculosis diagnosis
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-- acid fast staining -- culturing of the sputum -- PPD skin test |
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PPD skin test
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-- measure zone of "induration" in 72 hour -- positive test is induration that is more than 15 mm -- positive test indicates exposure only |
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Haemophilus influenzae
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-- gram-negative rod -- capsule |
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Haemophilus influenzae: reservoir
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nasopharynx
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Haemophilus influenzae: transmission
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-- respiratory droplets -- shared toys |
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Haemophilus influenza: diseases
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-- otitis media -- bronchitis, pneumonia -- meningitis * vaccine is avaliable |
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Pseudomonas aeruginosa
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-- gram-positive bacilli -- aerboic -- found in water -- grapelike odor when grown -- not a lactose fermenter |
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Pseudomonas aeruginosa: transmission
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-- water aerosol -- raw vegetables -- fruits |
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Pseudomonas aeruginosa: toxins
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-- endotoxins--> causes inflammation, G-shock, septicemia
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Pseudomonas aeruginosa: diseases
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-- eye ulcers -- pneumonia -- hot tub folliculitis -- severe in diabetics and patients w/ severe burns |
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Campylobacter
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-- gram-negative curved rod -- polar flagella -- microaerophillic -- motile |
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Campylobacter: transmission
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-- fecal oral -- polutry -- dogs and cats |
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Campylobacter: pathogenicity
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-- invades mucosa of the colon -- fever -- diarrhea w/ many stools a day -- self limiting 3-5 days |
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Campylobacter: complications
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-- arthritis -- guillain-Barre syndrome (nervous damage) |
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Shigella
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-- gram-negative rod -- non-motile -- facultative anerobe -- not a lactose fermenter |
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Shigella: reservoir
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-- colon |
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Shigella: transmission
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-- fingers -- flies -- food -- feces |
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Escherichia coli
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-- gram-negative rod -- ferments lactose -- facultative anerobe -- colonies w/ iridescent green sheen |
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Escherichia coli: reservoirs
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-- human colon -- crops where fecal fertilizer is used -- unpasteurized apple juice |
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Staphylococcus
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3 species: -- aureus -- epidermidis -- saprophyticus |
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Staphylococcus aureus
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-- gram-positive cocci -- grapelike clusters -- grow in yellow colonies on blood agar |
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Staphylococcus aureus: reservoir
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-- nose -- skin -- normal microflora |
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Staphylococcus aureus: transmission
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-- shaking hands -- sneezing -- surgical wounds -- via foods: egg containing dishes such as potato salad, custards |
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Staphylococcus aureus: predisposing factors
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-- IV drug abuse -- foreign body (sutures, artificial heart valve) -- spider bite |
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Staphylococcus aureus: toxins
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-- enterotoxin (GI) -- toxic shock syndrome toxin -- cytolytic toxin alpha (kills cells) -- skin exfoliating toxin (detaches epidermis from derma) |
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Staphylococcus aureus: enzymes
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-- coagulase--> converts fibrinogen into fibrin (blood clot) -- catalase--> degrades hydrogen peroxide -- toxins destroy RBC -- hemolysis -- complete destruction RBC called beta-hemolysis--> clear areas on the blood agar |
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Staphylococcus aureus: diseases/conditions
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-- gastroenteritis (food poisoning) 2-6 hours after eating -- abscesses and mastitis, subcutaneous, swelling pain -- impetigo, skin lesions -- post-surgical infections -- osteomyelitis: lytic lesions on imaging, pain in bones -- pneumonia: rapid w/ necrosis, high mortality -- scaled skin syndrome: diffuse epidermal peeling -- acute infective endocarditis: fever, malaise, heart murmur |
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Escherichia coli: diseases
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-- UTI fecal flora to urethra, pili help adhere to the mucosa -- sepitcemia: indwelling IV lines -- gastroenteritis: diarrheas, poor sanitation, undercooked hamburger meat -- neonatal meningitis: maternal fecal flora during birth, endotoxin causes shock, inflammation |
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ETEC Escherichia coli
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enterotoxigenic -- no inflammation -- toxin -- diseases: traverler's diarrhea |
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EPEC Escherichia coli
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enteropathogenic -- no toxin -- prolonged water diarrhea -- transient lactose intolerance (flattens villi) |
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EIEC Escherichia coli
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-- enteroinvasive -- invades intestinal mucosa -- diarrhea w/ fever and abdominal pain |
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EHEC Escherichia coli
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enterohemorragic -- verotoxin producing -- O157: H7 is MC serotype -- Mild diarrhea w/ bleeding and hemolytic-uremic syndrome |
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Helicobacter pylori
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-- gram-negative -- spiral gastric bacilli w/ flagella |
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Helicobacter pylori: transmission
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-- fecal oral -- saliva/kissing |
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Helicobacter pylori: infection
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-- can be asymptomatic -- invades mucosa -- supresses bicarbonate around pyloric sphincter -- casues gastritis and duodenal ulcers -- Type I carcinogen -- produces urease |
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Helicobacter pylori: breath test
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radiolabeled urea is swallowed and ammonia/CO2 is produced
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Salmonella
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-- gram-negative rod -- not a lactose fermenter -- motile |
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Salmonella typhi
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-- highly motile w/ capsule -- facultative anaerobe -- only found in humans, no animal reservoirs |
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Salmonella typhi: transmission
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-- fecal oral
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Typhoid fever
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-- headache -- abdominal pain -- constipation |
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Salmonella typhi: infection
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-- begins in __?___ region, reaches gut, lymph nodes, and blood -- 25% have rose spots, liver and spleen become infected -- replicates in macrophages |
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Nontyphoidal salmonella
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-- no capsule |
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Nontyphoidal salmonella: reservoir
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-- enteric tract of human and domestic animals, chickens and turtles |
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Nontyphoidal salmonella: pathogenesis
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-- invades mucosa of small intestine -- causes loose diarrhea -- 6-48 hours after incubation: nausea, vomiting, bloody stool, fever, abdominal pain |
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Methods of sterilization
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1. Ethylene oxide gas: covalently binds to proteins 2. UV light: effective but has no penetrating power 3. bacteriological filter: useful for small amounts of liquids |
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microbiological media
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-- anything bacteria can use for food
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3 forms of media
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1. liquid-->broth 2. solid-->agar 3. sugar for algae |
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Culture maintenance
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1. refrigeration2. mineral oil3. lyophilization
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