What factors do organisms that live in the GIT have to deal with to survive?
Antimicrobial defences- lysosomes, lymph tissue etc
Commensals- compete & create selective environment
Peristalsis & fluid movement- makes it difficult for microbes to adhere
Bile acids- can emulsify bacterial membranes & macromolecular structure
What are the 3 classifications of E.coli?
1) Commensal E.coli- can cause infection in immunolgically/medically compromised pts
2) Extraintestinal pathogenic E.coli (ExPEC)- only pathogenic outside gut
3) Enterovirulent- strictly pathogenic
Which of the following bacteria are an important cause of serious nosocomial infections?
c) Bacteroides fragilis
b) Enterococci- have acquired antibiotic resistance genes
Name 3 GIT commensal anaerobes that can cause disease in extra-intestinal sites when normal defenses are compromised?
What is the difference between a probiotic and a prebiotic?
A probiotic is good bacteria whereas a prebiotic stimulates growth and activity of good bacteria
How do commensal gut bacteria protect themselves from bile?
They produce bile modifying enzymes to reduce antimicrobial activities by doing the following:
How is gut microflora important for health?
Plays a digestive role:
-digestion and absoprtion of polysaccharides
Plays a protective role:
•competitive and selective environment
What bacteria might be involved in cholecystitis and colangitis?
•Commensals:Escherichia coli, Klebseilla pneumoniae, Enterococcus, Staphylococcus aureus
•Exogenous pathogens:Helicobacter pylori, Campylobacter, Salmonella typhi
Gram -ve or +ve and what kind of anaerobe?
a) Escherichia coli
c) Bacteroides fagilis
a) Gram -ve falcultative anaerobe
b) Gram +ve falcultative anaerobe
c) Gram -ve aerotolerant anaerobe
What is the predominant bacteria isolated from intraabdominal sepsis, bacteremia, and abscesses?