Opportunistic Infections Flashcards
(22 cards)
What are the frequently encountered opportunistic pathogens?
E coli, staph aureus, klebsiella pneumoniae, enterococcus, pseudomonas aeuriginosa, enterobacter, serratia, proteus, clostridium difficile
Which pathogens may cause nosocomial epidemics?
staph aureus, klebsiella pneumoniae, enterococcus, pseudomonas aeuriginosa, enterobacter, serratia
What are some local host factors which may put the patient at risk of opportunistic infections?
anatomical defects, wounds, burns, catheters, foreign bodies
What are some systemic host factors which may put the patient at risk of opportunistic infections?
extremes of age, leucopenia, malignancy, malnutrition, diabetes, liver disease, infection, treatment with antimicrobials, congenital immunodeficiency
What are the sources of the pathogens in an opportunistic infection?
either endogenous (patients own microbiota) or exogenous (someone else’s microbiota)
What must be considered in the treatment of opportunistic infections?
antibiotic susceptibility because nosocomial strains are often resistant and whether the patient is immunocompromised so will require bactericidal instead of bacteriostatic antibiotics
What is the most important prevention method of opportunistic infections?
aseptic technique (hand hygiene)
What are the features of pseudomonas?
gram negative rod, aerobic (strict or facultative), motile, non fermenting, non sporing, catalase and oxidase positive
Why does pseudomonas have a distinctive colour and smell?
because some species produce a pigment called pyocyanin which is green with a sweet odour
What environment do pseudomonas live in?
moist environments
What tests are used epidemiologically to figure out if the same strain of pseudomonas is causing the problem?
RFLP or MLST
What are the different species of pseudomonas?
pseudomonas aeuriginosa, burkholderia cepacia, senotrophomonas maltophilia, burkholderia pseudomallei
What does burkholeria pseudomallei cause?
pneumonia (meliodosis) - particularly in NT
Which patients are particularly at risk of an opportunistic infection from pseudomonas?
cystic fibrosis patients
Why is pseudomonas aeuriginosa difficult to treat?
because all strains are intrinsically resistant to antibiotics and weak disinfectants and can readily acquire resistance from other bacteria
What superficial infections are caused by pseudomonas aeruginosa?
otitis externa, folliculitis, keratitis, corneal ulcer
What deep and systemic infections are caused by pseudomonas aeruginosa?
pneumonia, UTI, endocarditis, osteomyelitis, septicaemia, endopthalmitis
What features allow pseudomona aeruginosa to adhere to the epithelium?
flagella, pili and LPS
What protein to the LPS core of pseudomonas aeruginsoa bind to and what implication does this have for CF patients?
CFTR - means that CF patients the bacteria dont adhere as well so are in the airways for longer
What does pseudomonas aeruginosa produce?
a biofilm
What are the features of pseudomonas aeruginosa when they are in a biofilm?
they are non motile, produce more capsule, are more adherent, less invasive, shorter LPS, slowed growth and increased resistance to antibiotics
What is quorum sensing and what is its role?
communication between bacteria - allows the bacteria to know when to produce the biofilm
