Notes in 3- P&H

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Published	02/10/2024	Clinical infection is characterised by signs and symptoms e.g.– {{c1::inflammation}} – {{c1::pain}} – {{c1::pyrexia}} → (raised body temperature) – {{…
Published	02/10/2024	a {{c1::pathogen}} is an organism which can cause disease a {{c1::commensal}} is an organism which is part of normal flora e.g. E. coli in the gu…
Published	02/10/2024	The commensal organisms in the flora can become pathogens depending on whether the host has sufficient or compromised {{c1::immunity}}
Published	02/10/2024	Koch's Postulates                                      …
Published	02/10/2024	{{c1::Pathogenicity}} is the capacity of a micro-organism to cause an infection.Requirements: – {{c2::Infectivity}} • Ability to become established on…
Published	02/10/2024	Virulence vs InfectivityWhat are the differences?
Published	02/10/2024	Components of virulence:1- {{c1::Invasiveness}}2- {{c1::Toxin production}}3- {{c1::Evasion of immune system}}
Published	02/10/2024	Invasiveness:• Streptococcus pyogenes (Group A streptococci) → (carried in throat as a commensal)Can cause invasive infections in certain situati…
Published	02/10/2024	Toxins: • {{c1::exotoxins}} are released extracellularly by the micro-organism • {{c1::enterotoxins}} are exotoxins which act on the GI tract • {…
Published	02/10/2024	{{c1::Superantigens}} are are toxins that cause overwhelming cytokine production that leads to toxic shock.• Certain exotoxins of Strep pyogenes and S…
Published	02/10/2024	Groupings of streptococci (A-G) are called {{c1::Lancefield groupings}} (based on surface antigens)A, B and D are most important clinically.----------…
Published	02/10/2024	{{c1::Coagulase test}} is used to differentiate Staphylococcus aureus (Coagulase positive) from (Coagulase Negative) Staphylococcus (CO…
Published	02/10/2024	Staphylococcus aureus are commonly penicillin resistant due to {{c1::β-lactamase production}} By a different mechanism, some strains ar…
Published	02/10/2024
Published	02/10/2024	{{c1::Community-associated MRSA}} are a strain of MRSA that are characterised by the KmecA gene.They are often less multiresistant.They produce cytoki…
Published	02/10/2024	{{c1::Panton-Valentine leukocidin (PVL)}} is a cytokine/potent toxin released by CA-MRSA which leads to the destruction of respiratory tissue and…
Published	02/10/2024	Coagulase-negative staphylococci are skin commensals that can be pathogenic in the {{c1::presence of foreign bodies/prostheses}} (1) or {{c1…
Published	02/10/2024	Clostridium species: (gram-positive bacteria)----------------------[1] {{c1::Clostridium perfringens}} • found in soil and normal commensal in hu…
Published	02/10/2024	Bacillus species - gram positive bacteria----------------------[1] {{c1::Bacillus anthracis}}- Associated with exposure to infected animals or contami…
Published	02/10/2024	All gram-negative bacteria share a common feature in the bacterial cell wall which is the virulence factor {{c1::lipopolysaccharide}} also known as en…
Published	02/10/2024	Gram negative cocci1- {{c1::Neisseria spp}} → two strains (meningitidis & gonorrhoeae)2- {{c1::Moraxella catarrhalis}}
Published	02/10/2024	Neisseria spp are gram negative bacteria cocci species.------------------------[1] {{c1::Neisseria meningitidis}} (meningococcus) • Causes mening…
Published	02/10/2024	Escherichia coli→ dominant in normal flora of gut------------------[1] {{c1::Enterotoxogenic}} E.coli   - most common cause of traveller’s diarr…
Published	02/10/2024	{{c1::Cholera}} caused by Vibrio cholerae (colonises small intestine) → production of EnterotoxinIncreases cAMP levels → Inhibits uptake of …
Published	02/10/2024	Salmonella spp - gram negative coliform bacteria------------------------ [1] {{c1::Salmonella enterica}} > 1500 serotypes• Does not ferment la…
Published	02/10/2024	{{c1::Coliforms}} are gram-negative bacteria that are always present in the digestive tracts of animals, including humans, and are found in their wast…
Published	02/10/2024	The five worst bacteria are all gram {{c1::negative}} bacteria
Published	02/10/2024	Four forms of virus infections:[1] {{c1::Acute}} - characterized by rapid onset of disease, a relatively brief period of symptoms, and resolution with…
Published	02/10/2024	{{c1::Influenza A}} is a virus that infects cells of the respiratory tract and leads to the destruction of respiratory epithelium,Altered cytokine exp…
Published	02/10/2024	How do novel influenza viruses become generated?Influenza A as an example:1- {{c1::Antigenic DRIFT}}: Minor changes (natural mutations) in the ge…
Published	02/10/2024	Non-human hosts for influenza A viruses play a key role in generating new virus types through {{c1::Antigenic Shift}}.
Published	02/10/2024	Enterovirus infections: (70+ stains known) Poliomyelitis ({{c1::poliovirus}}) Aseptic meningitis (many enteroviruses) Myocarditis ({{c1::coxsacki…
Published	02/10/2024	{{c1::Latent Virus Infections}} are infections that stay for lifeFor Example: Herpes simplex virus – cold sores (type 1) and genital lesions (type 2)A…
Published	02/10/2024	Examples of virus-induced tumours:{{c1::Papillomaviruses}} – cervical carcinoma {{c1::Retroviruses}} – lymphomas and leukaemias
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