Staphylococcus species

• 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

Staphylococcus aureus

Skin infections:

• 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

Staphylococcus aureus

Gut intotoxication:

• 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!

Staphylococcus aureus

Gut intoxication symptoms:

• 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

Stapyhlococcus aureus

that causes TSS

Toxic Shock Syndrome:

• 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

Staphylococcus aureus

Signs and symptoms of TSS:

• 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

Staphylococcus aureus

Systemic infection:

• 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

Streptococcus species

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

Streptococcus aureus

affects on blood agar

• 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

Streptococcus species

Bergey's Manual of Systematic Bacteriology:

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

Streptococcus pneumoniae

Pneumonicoccal Pneumonia

Occurance:

• 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

Streptococcus pneumoniae

Mode of transimission:

Incubation period:

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

Streptococcus pneumoniae

Disease process:

Diagnosis:

• 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

Streptococcus pneumoniae

Treatment:

Immunity:

• 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

Streptococcus mutans &

Streptococcus salivarius

• 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

Strep. mutans

Attaches to:

• enamel of tooth

Strep. salivarius

Attaches to:

• buccal and gingical epithelium

• 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

• 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

Streptococcus pyogenes (group A beta hemolytic)

Strep Throat:

• 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

Streptococcus pyogenes

Glomerulonephritis:

• 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

Streptococcus pyogenes

Rheumatic fever:

• 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

Streptococcus pyogenes

Scarlet fever:

• 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

Streptococcus pyogenes

Erysopelas:

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

Streptococcus pyogenes

Impetigo:

•  may be caused by Staph. aureus or Strep. pyogenes

• burns