Infection & UTIs Flashcards
What are host risk factors for infection?
- Compromised host
- Extremes of age
- Stress + starvation
- Congenital + acquired immunodeficiency
- Disruption of normal physiological + anatomical barriers
How can bacteria cause disease?
- Access
- Adherence
- Growth
- Invasion
- Protection from killing by immune system
- Protection from killing by antibiotics
What are the risk factors for UTIs?
- Being female
- Abnormal urinary tract
- Pregnancy
- Catheterisation
- Diabetes?
What is the most common cause of UTIs and why?
E.coli -
- Pili improve adhesion
- Haemolysin increase invasion
- Capsule
- Siderophores scavenge iron for growth
- Antibiotics resistance is common
What are other causes of UTI?
- Other gram -ve gut bacteria e.g. Klebisella
- Staph
- Faecal streps
- Pseudonomas - big problem with sticking to catheters
What is cystitis?
A bladder infection - lower UTI
What is pylonephritis?
Upper UTI
What is sterile pyuria?
White cells in urine but no microbes
What is asymptomatic bacteriuria and who are the exceptions that receive treatment?
Positive lab results but no symptoms - pregnant women & children
How do you test for UTI?
Dipstick - look for nitrates & blood
What are the 5 antimicrobial targets & drug examples?
- Cell wall - beta lactams (penicillin) + glycopeptides (vancomycin)
- Nucleic acid synthesis - quinolones (floxacin)
- Cell membrane - lipopeptides (daptyomycin)
- Nucleic acid precursor synthesis - trimethoprim
- Protein synthesis - tetracyclins, macroglides, aminoglycosides
Which particular drug target is the most toxic to humans?
Targeting the cell membrane as human cells has cell walls.
Protein synthesis targets are not as toxic as different ribosomes are involved
What are the 3 different times of giving ABX?
- Empirical - before causative pathogen known
- Prophylactic - prevent infection e.g. surgery
- Targeted - therapy informed by definitive diagnosis
What it mean when ABX are broad spectrum?
They can target all bacteria from gram -ve to gram +ve
What are the 4 mechanisms of ABX resistance?
- Eject drug from cell
- Use different metabolic process
- Alter binding site/target
- Break down drug - enzyme inactivation
