Gram (+) Cocci – Flashcards

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Staphylococcus species

 

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  • gram [+] cocci
  • is a normal resident of nose, skin, gut, and vagina (usually not causing disease)
  • Staph epidermis-normally harmless resident of the skin which is associated with serious nosocomial(aquired in hospital) infections (especially surgery)
  • is pus forming (pyogenic)
  • pathogenic forms of this strain produce coagulase which converts fibrinogen into fibrin making blood clot- this in turn makes staph more virulent because the clot resist phagocytosis
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Staphylococcus aureus

Skin infections:

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  • Furuncle- infections of hair follicle or skin gland known as boils
  • Carbuncle- more severe infection involving sucutaneous(deepest layer of integumentary system under dermis) at nape of neck, upper back, or buttocks
  • Abcess-pyogenic lesion staph aureus infection
  • Stye- meiobomian gland (modified sebaceous gland at rim of eyelids) infected by Staph aureus
  • Impetigo- lesions that usually starts on face/nose and is spread from scratching- is also causes by streptococcus pyogenes (common in kids)
  • SSSS- Staphylococcal scalded skin syndrome- strain of staph aureus that contains plasmid (packet of DNA separate from chromosomal DNA and can replicated itself) for exfoliatin
  • exfoliatin cause skin to peel off exposing reddened area beneath- infants and kids are affected most-occurs by mouth and nose and can spread
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Staphylococcus aureus

Gut intotoxication:

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  • 2nd most common cause of food poisoning
  • it is an intotoxication- NOT infection
  • you must ingest preformed enterotoxin (protein toxin of the intestines- associated with high protein foods
  • is intoxication of enterotoxin staph secretes
  • toxin likes warm conditions and promotes growth- toxin is stable at 100 degrees celsius
  • cold inhibits toxin
  • Source of bacteria is usually from food handlers-their handsores or snot
  • Contamination usually occurs after cooking
  • commonly found in pastries, potato salad, chicken salad
  • small and flat containers are best for less microorganism growth
  • food sitting out too long will grow bacteria!
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Staphylococcus aureus

Gut intoxication symptoms:

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  • 1st appear after 2-4hours after ingestion of toxin
  • Severe nausea, cramps, vomiting (projectile)
  • usually self limting
  • in 1-2 days you should be ok
  • deaths are rare
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Stapyhlococcus aureus

that causes TSS

Toxic Shock Syndrome:

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  • An intoxication w/ enterotoxin F that staph secretes
  • 1st described in 1978
  • commonly assocaited with menstrating females using tampons
  • has Mg2+ depletion
  • associated with c-sections, wound infections, and surgical wound infections where packing is used to absorb exudates
  • 1980- 900 cases 97%female-5%mortality
  • 1983-324 cases
  • strains of staph aureus that cause TSS are always penicillin resistant as well as methicillin
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Staphylococcus aureus

Signs and symptoms of TSS:

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  • High fever
  • vomitting- profuse diarrhea
  • sun-burn like rash
  • strawberry tongue
  • hypotension (b/c of vomitting and diarrhea)- leading to circulatory shock
  • if female is menstrating and using tampons while vomitting and throwing up, then must go see doctor
  • no immunity and 30% reoccur
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Staphylococcus aureus

Systemic infection:

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  • usually spread from skin lesions
  • not common in healthy individuals
  • you're are risk after extensive surgery- can be caused by bed sores
  • can infect all systems: menigitis, pneumonia, encocarditis, osteomylitis, seticemia
  • primary infection of respitory, known as Staph pneumonia) occurs in immune supressed or deficient people
  • treatment: PCN-G or PCN-V (oral)
  • if peniciilin resistant then Cephalosporin
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Streptococcus species

;

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  • Gram (+) cocci
  • there are many pathogenic species
  • easier to kil unlike Staph. aureus
  • can be killed by disinfectants, anitseptics, and physical control measures
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Streptococcus aureus

affects on blood agar

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  • Alpha hemolytic- partial hemolysis
  • Beta hemolytic- complete hemolysis
  • Gamma hemolytic- no hemolysis

according to what Ab it stimulates host to produce

Group A-O strep;exist

Group A and B most important

there are 80+ serotypes of Strep. pneumonia

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Streptococcus species

Bergey's Manual of Systematic Bacteriology:

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  • Pyogenic species: Strep. pyogenes & Strep. pneumoniae
  • Oral species: Strep. mutans & Strep. salivarius
  • Enterococci (in gut): Strep. faecalis
  • Lactic acid- Strep. lactis

 

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Streptococcus pneumoniae

Pneumonicoccal Pneumonia

Occurance:

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  • most common cause of Lobar pneumonia (lower lung) 60%-80% of all pneumonia
  • endogenous infection- ppl w/ predisposing factors: diabetes, physical injury to bronchial treet, flu
  • Bronchopneumonia- secondary infection of old and young usually not caused by Strep. pneumoniae
  • Mortality 5-10% with treatment 20-40% were old age
  • 23 capsular types of 80+ serotypes- causes 90% of disease
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Streptococcus pneumoniae

Mode of transimission:

Incubation period:

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  • resevior-Homo sapiens
  • MOT- Aerosols, direct oral contact, and snot rags
  • IP- 1-3 days
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Streptococcus pneumoniae

Disease process:

Diagnosis:

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  • acute infect with sudden onset of symptoms: chills, fever, dyspnea, cough with rusty sputum(blood), thick exudate with fibrin fills bronchioles and aveoli which can lead to consolidation into slid foci
  • Diagnosis: x-rays, isolation of organisms from sputum, quelling reaction
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Streptococcus pneumoniae

Treatment:

Immunity:

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  • PCN-G (oral) or erythromyocin if PCN sensitive
  • Immunity: Pneumovax/ polyvalent- 23 strain vaccine given once for life
  • if you have no sleep then you need booster every 5 years
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Streptococcus mutans &

Streptococcus salivarius

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  • Gram (+) cocci
  • occur in oral cavity in high numbers
  • contribute to plaque, dental cavities, gingivitues, and periodontal disease
  • if gets into blood can cause subacute bacterial endocarditis- no signs until heart valve damage is done
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Strep. mutans

Attaches to:

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  • enamel of tooth
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Strep. salivarius

Attaches to:

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  • buccal and gingical epithelium
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Streptococcuse faecalis
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  • generally not pathogenic in gut
  • may cause disease elsewhere:
  • UTI, abdominal trauma (gut shot)
  • if it is a contaminate of food it maye produce enterotoxin causing food poisoning
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Streptococcus lactis
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  • causes milk to sour because of lactose fermentation (sour fermentation)
  • is used to produce buttermilk and some cheese- sour cream
  • many food made with this
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Streptococcus pyogenes (group A beta hemolytic)

Strep Throat:

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  • Pharyngitis
  • one of the most common bacterial infections of human
  • is spread by aerosols and snot
  • less severe as adult because exposed as a child- adults already have the ab to kill it
  • treatment: usually self limiting, use PCN
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Streptococcus pyogenes

Glomerulonephritis:

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  • occurs secondary to strep throat
  • occurs as a type 3 hypersensitivity reaction
  • 80-90% get over it- the rest need kidney transplant because glomeruli is destroyed so you can not produce urine

 

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Streptococcus pyogenes

Rheumatic fever:

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  • occurs secondary to strep infections
  • occurs as type 3 hypersensitivity reaction in kids 6-15
  • rare- occurs .5% of strep infections
  • most common cause of heart valve damage in children
  • treatment: asprin and cortisol
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Streptococcus pyogenes

Scarlet fever:

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  • strep throat infection with strain that produces erthyogenic toxin
  • after two days incubation you develope rash on upper body with fever
  • have strawberry tongue
  • treatment- PCN uncommon today
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Streptococcus pyogenes

Erysopelas:

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  • acute infection of dermis
  • red skin
  • occurs in infants and adults over 30
  • expecially females
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Streptococcus pyogenes

Impetigo:

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  •  may be caused by Staph. aureus or Strep. pyogenes
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Streptococcus pyogenes can cause wound infections, especially_______?
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  • burns
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