Host microbe interactions Flashcards
Which immune system complements are activated to bacteria?
phagocytes
antibody and B lymphocytes
compliment
Which immune system complements are activated to Viruses?
T lymphocytes
antibody and B lymphoctes
What is produced by the keratinocytes that has antimicrobial properties?
Defensins
What do the sebaceous or sweat glands secrete that has antibmicrobial properties?
Fatty acids
What is taenia paedis? Where is it most common?
cracking of the skin btw the toes
in patients who are debilitated, with pressure sores in areas that havent been taken good care of
Fixed dialation of the bronchus
Decreases the clearance of mucus –> increases the sputum stagnancy and increases infection risk
Which immune system complements are activated to Fungi?
Phagocytes
T lymphocytes
Eosinophils
Risk factors that increase the risk in genito-urinary system?
Imparied bladder emptying
Catheterisation
What are phagocytes?
Part of innate imune response
Swallows the organisation after opsonisation
How do phagocytes swallow and kill organisms?
Via oxygen dependent or independent mechanisms
What immune system component is responsible for the major control for control of bacteria and fungi like Step,Staph, coliforms, aspergillus and candidia?
Phagocytes
What deficiency is seen in those with haematological malignancy like acute leukaemia, myelodysplasia or cytotoxic chemotherapy?
Phagocyte deficiency
What is the major function of the CD4 Helper T cells?
Enhance the phagocytes killing of organisms
What is the major function of the Cytolytic T-lymphocytes?
Find cells that have abnormalities on the surface (either due to infection or cancer) and kill them directly
Don’t need help from others
Which immune system component is helpful to kill intracellular organisms and infected cells?
T lymphocytes
Which conditions are T lymphoctes deficient in?
HIV infection (acquired deficiency in CD4+ lymphocytes)
Lymphoma
Primary immunodeficiency syndromes (e.g. SCID)
Which cells mature into plasma cells?
B cells
Which cells produce immunoglobulins?
B cells or immunoglobulins
Which immunoglobulins are produced first and what are their features?
IgM
Fast, first response, weak affinity for antigen
Which immunoglobulins are produced second line and what are their features?
IgG
Later on, strong affinity for antigen, takes a few weeks to reach max level
How do immunoglobulins help to kill antigens?
Stick to the suface of antigen and trap them for the phagocytes to come and swallow them
Which disease has immunoglobulin deficiency as a feature?
Myeloma
Primary immunodeficiency syndrome
Which disease affects CD4+ T lymphocytes?
HIV
progressive immunodeficiency
When is opportunistic infection seen in HIV patients?
progressive immunodeficiency that has been there for some time
Which pathogens commonly cause invasive infections in those with HIV regardless of CD4 count?
pneumococcal (S. pneumoniae) disease (bacteraemia/meningitis/empyema
What are the infections a person with CD4 count <350 is susceptible to?
Mycobacterium tuberculosis, candidiasis
What are the infections a person with CD4 count <200 cam get?
Pneumocystis jirovecii, Toxoplasma gondii
What are the infections a person with CD4 count <100 can get?
Cryptococcus neoformans, Cytomegalovirus (CMV)
Which conditions cause functional hyposlenism?
sickle cell disease, cirrhosis and coeliac disease
RTA with spenic bleeding, what do you do?
Give vaccination to present susceptibilty to invasive infection from encapsulated organisms
Splenectomy
Antibiotic prophylaxis with amoxicillin
Which encapsulated organisms increase invasive infection risk in hyposplenism?
Streptococcus pneumoniae (pneumococcus)
Haemophilus influenzae type B (HiB)
Neisseria meningitidis (meningococcus)
What is hyposplenism?
Decreased spleen function
A few common causes of hyposplenism include:
Splenectomy (trauma, ITP< klymphona etc.)
Fucntional hyposplenism (sickle cell, cirrhosis and sickle cell disease)
What are the symptoms shown generally by immunocompromised indiviuals?
Not general symptoms like normal people
Fever may be absent
Lack of inflammatory response (CRP / neutrophilia)
Non-specifically unwell, no localising features
How do you treat those with infection if they are immunocompromised?
broad spectrum antibiotics in those who are immunocompromised
Is immunosuppression levels in acute leukaemia treated with bone marrow transplant high?
Yes, super high
What are the strong association steroids have with regards to their usage?
fungal infections (Candida, Aspergillus)
What do anti-TNF alpha therapies have a strong association and risk to?
Intracellular infections by Mycobacterium tubercuclosis
Fungal infections
What drugs are used to treat serious haematological malignancies?
Purine analogues (fludarabine, cytarabine)
Which infections are increased wrt to the risk if people use purine analogues?
Viral infections (especially Herpes Simplex Virus and Varicella Zoster Virus) Pneumocystis jirovecii
Why is co-trimoxazole prophylaxis used in patients with HIV?
To prevent pneumocystitis jerovecci pneumonia
Which antigungal agent is used in those with bone bmarrow transplants and why?
Itraconazole
to prevent invasive aspergillosis
Which drug is given to patients with splenectomy and why?
Penicillin V to prevent pneumococcal disease
Which groups are give influenza vaccines?
Pregnant women Chronic heart/lung/kidney/liver disease Immunocompromise Diabetes Aged >65 years
Which groups are given vaccination for streptococcus penumoniae infection?
Chronic heart/lung/kidney/liver disease Hyposplenism Immunocompromise (including HIV infection) Diabetes Aged >65 years
Which groups are given haemophilus influenzae vaccine?
All children
Has now essentially eliminated majority of these infections
