Transcript Bergey`s Volume 2 – Gram Positive Bacteria of Importance

Bergey’s Volume 2 – Gram
Positive Bacteria of Importance
1) Gram positive spheres:
•Micrococcus
•Staphylococcus
•Streptococcus
Micrococcus
• Demos chromogenicity
• Isolated from human and
animal skin, dairy
products and beer
• Breaks down compounds
in sweat to produce odors
• Not typically pathogenic
• Can create superficial
infections in immuno
suppressed
Staphylococcus
• Assoc with skin, skin glands, and
mucus memb.
• High osmotic pressure/low H2O
• Readily deposited on fomites
• Most important pathogen =
S. aureus
• Can cause pathogenesis at 3
locations:
– Skin
– G.I. Tract
– Lower respiratory
Staphylococcus and skin
infections
• Coagulase + SA highly
correlated with toxin
production
• Exfoliative toxin and SSS
• Folliculitis --> stye or boil
• Also cases of impetigo
Staphylococcus and GI tract
• Food intoxication (Staph
and Clostridium)
• From staph enterotoxin
• Staphylococcal food
poisoning is acute
• In foods containing hi
protein
– Ham
– Poultry
– Potatoe and egg salads
Staphylococcus and the
respiratory tract
Most cases of Staph RTI are nosocomial in origin
Wash hands well and often!!!
Streptococcus
• CA of disease variety
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–
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–
–
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Dental caries
Sore throat
Otitis media
Septicemia
Pneumonia
Endocarditis
• Arsenal of toxins/enzymes
Many diseases caused by Strep A
= S. pyogenes
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–
–
–
Hemolysins
Leukocidins
Erythrogenic toxin
Cardiohepatic toxin
Cell wall proteins and
carbo’s
Strep A – S. pyogenes
• B-hemolytic
• Respiratory -> invasive
– Strep throat -> septicemia
– Cross-reactivity of Ag’s can
cause rheumatic fever
(sequela)
– Erythrogenic toxin causes
red rash of scarlet fever
Strep A – S. pyogenes and skin
• “flesh-eating” bacteria
• Rapidly destroys tissue
and invades
– Cellulitis (tissue)
– Myositis (muscle)
– Necrotizing fasciitis
(covering)
• STSS = Streptococcal
Toxic Shock Syndrome
Typical pneumonia:
S. pneumoniae
• No toxin related to this
disease
• Hi fever, chest pain,
difficult breathing
• Inflamed lungs
– Vasodilation
– Alveoli fill with RBC’s
– Alveoli fill with fluid
Vaccine of purified
capsule