Healthcare associated infections Flashcards
CA-UTI
- what
- prevalence
- risk factors
- other sings
- pyuria?
Catheter associated UTI
- The presence of bacteria in the urine is common
- Prevalence - approx 10% of patients with catheters
- women, duration poor care
- specific symptoms might be lacking: fever, lethargy, flank pain, confusion
- the presence of pyuria alone is not diagnostic, the absence of pyuria suggests and alternate diagnosis
- the presence / absence of smelly / cloudy urine is not diagnostic
- Cultures usually show one bacterial species: if find presence of lots of bacteria was probably contaminated
Strategies to reduce CA-UTI
avoid insert using antiseptic technique remove appropriate care condom catheters
Not to do to reduce CA-UTI
antibiotic prophylaxis antibiotics in the urine bag other prophylactics (e.g. cranberry) catheter irrigation regular testing
Other infections caused by candida
nappy rash
Thrush oralgenital
fingernails - gloves, wet hands, nail biting
disseminated candidiasis: leukaemia, neutropenia
Biofilm
microbial community of cells that attach to a substrate or interface or to each other embedded in a matrix of extracellular polymeric substance
Bacterial factors
most common bacteria: staph. epidermis staph. aureus Factors - non-specific (hydrophobicity, electrostatic forces) - Adhesive proteins - polysaccharide intracellular adhesion
Microorganisms
Gram positives: noscominal bacteraemic events, mostly staph epidermididis and aureus
Gram negatives: 30% of all episodes of bacteremia at most institutions
Fungi: candida
Devices that favour bacterial adhesion
PVC»_space;»> silicon
Synthetic > biomaterial
textured > smooth
polymeric tubing > wire mesh
Host factors
can affect bacterial adherence to the device e.g. host tissue ligands (fibronectin) Immune response
Problems with biofilm associated bacteria
Antibiotics hard to reach bacteria deeper in biofilm
Change of phenotype
Change of cell surface proteins - increases antibiotic tolerance
Slower growth rate - more resistant to antibiotics
Persister cells: specialised survivor cells that are resistant to antibiotics
Difficult to determine antibiotic resistance
Blood tests might be negative for bacteremia after antibiotic treatment, but bacteria biofilm might still be present
Prevention
reconsider requirement for device
hand washing before and after touching device
Place the device appropriately under aseptic conditions (avoid femoral site)
Monitor devices carefully for signs of infection
Remove unessecary devices
Clostridium difficile gut colonisation in inpatients
- persons most at risk
hospital patients receiving antibiotics
Longer than 1 week in hospital
other treatments that disrupt the colonic flora: removes competition, allows c. difficile to grow
How does C. difficile survive antibiotic treatment
may be sensitive to but survives as endospores and outcompetes other species where treatment stopped
About endospores
only produced by a species of bacillus and clostridium
A dormant, survival structure, not reproductive
Killed by: heat autoclaving, sporicidal chemicals
Not killed by: heat pasteurisation, antibiotics, oxygen
Clostridium difficile pathogenesis and drastic treatment
toxins attach to epithelial cells of the colon, they’re endocytosed into those cells
Endosome gets acidified, protein changes its conformation and gets secreted into the cytosol where it effects G protein glucosylation
IF severely inflamed, colon may need to be surgically removed, may perforate and may be fatal
