Med Micro Flashcards
How humoral immunity is compromised
- damage to B cells
- removal or functional inactivation of spleen
Definition of neutropenia
< 1 x 10*9/l neutrophils
Examples of physical barriers
- PH
- flushing mechanism
- secreted substances (IgA)
- presence of normal flora
How skin acts as a physical barrier
- dry
- acidic pH
- Sweat
- normal flora that produce bacteriocins
How does loss of acid in alimentary tract affect?
Permits colonization of stomach and upper intestine with micro-organisms (esp gram pos)
How does the normal flora protect against pathogens in alimentary tract?
- occupy all adherence sites
- consume nutrients
Problems with graft vs host disease
- allogeneic recipients at risk
- donor T cells attack recipients tissue
- can be life threatening
- leads to increased immuno suppression
Times at which risk is present
- pre-engraftment
- post-engraftment
- late
Describe risk pre-engraftment
- neutropenia and mucositis and invade devices
- highest risk period (bacteria and yeasts, reactivation HSV)
- use haemopoietic growth factors to shorten neutropenia
Describe risk post-engraftment
- from neutrophil recovery to day 100
- still at risk for certain organisms
- increased risk if GvH
Types of organisms that can cause infection in immunocomp host
- bacterial
- fungal
- viral
- parasitic
Bacteria that cause infection
- gram neg (p aeruginosa)
- gram pos (s aureus, viridans strep)
- influence of antibiotics in selecting resistant organisms
Viruses that affect immunocomp host
- newly acquired
- reactivated HSV (acyclovir)
- CMV (Ganciclovir)
Fungi that affect immunocomp host
- candida
- moulds/ filamentous fungi (aspergillus)
,miscellaneous organisms that affect immunocomp host
- toxo
- pneumocystitis jiroveci pneumonia
- mycobacteria
How to prevent infection in ICH
- decrease exposure (isolation)
- supportive (nutrition)
- immunization (not live vaccines)
Options for prophylaxis in ICH
- fluoroquinolones
- cotrimoxazole
- acyclovir
- Ganciclovir
- antifungal
Definition of pre-emptive therapy
- initiation of therapy of a probable very early sub clinical infection as detected by a sensitive screening test
Approach to ICH
Intensive investigations
Empiric therapy with broad spectrum antibiotics
Rapid initiation of therapy
Prolonged courses of antibiotics
Advantages of syndromic approach to STIs
- treatment given at first visit so delays are Voided
- cost effective (no lab tests)
- treatment covers most likely pathogens
- enables nurses to manage STIs
- standardizes diagnosis etc (allows for surveillance)
Disadvantages of syndromic approach to STIs
- over diagnosis and over treatment
- over treatment of partners of women with vaginal discharge (social consequences)
Clinical presentations of candida
- skin (warm and moist)
- nails (washerwoman)
- mouth (oral candidiasis)
- vulvovaginitis (curdy discharge and pruritis)
- chronic mucocutaneous candidiasis (children with deficiency of cellular immunity)
- disseminated (endocarditis)
How does trichomonas vaginalis multiply?
By longitudinal binary fission
Discharge of trichomonas
Yellowish
Foul smelling
Frothy
