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Staphylococcus aureus - Boils: Walled off from body with fibrin - Can produce toxic shock superantigen - MRSA: Methicillin-resistant S. aureus - Major cause of nosocomial infections (in hospitals) - Some strains make exfoliative toxin (scalded skin syndrome).
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Staphylococcus aureus - Boils: Walled off from body with fibrin - Can produce toxic shock superantigen - MRSA: Methicillin-resistant S. aureus - Major cause of nosocomial infections (in hospitals) - Some strains make exfoliative toxin (scalded skin syndrome). Skin and Soft-Tissue Infections Figure 26.2
Streptococcus pyogenes - Best known for causing sore throats and immunological sequelae, such as rheumatic fever - Also necrotizing fasciitis (“flesh-eating” disease) - Many prophages carry virulence factors. Skin and Soft-Tissue Infections Figure 26.3
Viruses cause a maculopapular skin rash. - Usually infects through respiratory tract - Paramyxovirus: Rubeola (“measles”) - Herpes virus: Chickenpox, shingles - Togavirus: Rubella (“German measles”) Skin and Soft-Tissue Infections Figure 26.4
normal TB show tubercules
Sexually Transmitted Diseases Syphilis - Caused by the spirochete Treponema pallidum - Primary syphilis: Chancre at site of infection - Secondary syphilis: Generalized rash - Tertiary syphilis: Effects on heart and CNS Figure 26.11
Sexually Transmitted Diseases Chlamydia - Most frequently reported STD in U.S. - Caused by unusual Gram-negative bacteria - Chlamydia trachomatis - Chlamydia pneumoniae - Obligate intracellular pathogens - Both cause STDs, as well as pneumonia and trachoma of the eye. Figure 26.12
Sexually Transmitted Diseases Gonorrhea - Caused by the Gram-negative diplococcus Neisseria gonorrhoeae - Most infected men exhibit symptoms, while most women are asymptomatic. - Binds to CD4+ T cells, inhibiting T-cell activation Figure 26.13
Central Nervous System Infections • Meningitis • - Infection of membrane surrounding brain • - Some bacteria cross blood-brain barrier. • - Streptococcus pneumoniae • - Haemophilus influenzae • - Neisseria meningitidis Figure 26.16D Figure 26.16B - Has thick capsule and type IV pili - Dangerous if gets into bloodstream - Crosses from capillary into cerebrospinal fluid - Once in meninges, very difficult to treat - Effective vaccine to capsule components
Figure 26.18 Figure 26.19
Animation: Retrograde Movement of Tetanus Toxin to an Inhibitory Neuron Central Nervous System Infections Click box to launch animation
Prions - Proteinaceous infectious particles - Cause spongiform encephalopathies - Improperly folded proteins form aggregates that damage the brain. - Most mammals suffer from these diseases. Figure 26.20