Microbiology in GI Flashcards by Anna Marshall

Is all colonisation permanent?

No some is transient

How well did you know this?

Not at all

Perfectly

When does colonisation begin?

At birth: Differences in vaginal and C secion

Not all colonisation is normal

How well did you know this?

Not at all

Perfectly

What are the host defences of the GI tract?

Acid in stomach
Normal gut flora
Peristlasis
Antimicrobial compounds

How well did you know this?

Not at all

Perfectly

What are the 3 main groups of bacteria in the GI tract?

Enterobacteriaceae (gram negative bacilli)
Enterococcus (gram positive cocci)
Anaerobes

How well did you know this?

Not at all

Perfectly

Give examples of enterobactericeae?

E coli
Klebsiella
Enterobacter
Proteus

How well did you know this?

Not at all

Perfectly

Give examples of Enterococci?

Enterococcus faecalis (more common)
Enterococcus Faecium

How well did you know this?

Not at all

Perfectly

Give examples of anaerobes in the gut?

Gram negative baccilli- Bacteroides

Gram positive bacilli = C diff

How well did you know this?

Not at all

Perfectly

What is colonisation?

The establishment of a micro organism on or within a host; may be short lived.

How well did you know this?

Not at all

Perfectly

What is virulence?

Likelihood of causing disease

How well did you know this?

Not at all

Perfectly

What is an oopportunistic pathogen?

Pathogen which would not normally cause an infection in a normal host but will in an immunocomprimised host

How well did you know this?

Not at all

Perfectly

What tests can microbiology do to diagnose infection?

Microscopy: stool, urine, CSF, sputum, pus
Culture 
Serology
Antigen detection 
PCR/molecular studies

How well did you know this?

Not at all

Perfectly

Which immune cells are commonly seen in bacterial infection?

Phagocytes

ANtibodys and B lymphocytes

How well did you know this?

Not at all

Perfectly

Which immune cells are commonly seen in viral infection?

T lymphocytes

How well did you know this?

Not at all

Perfectly

Which immune cells are commonly seen in Fungal infection?

Phagocytes, T lymphocytes and (eosinophils)

How well did you know this?

Not at all

Perfectly

Which immune cells are commonly seen in helminth and parasitic infection?

Eosinophils and mast cells

How well did you know this?

Not at all

Perfectly

What is primary peritonitis?

Transfer of bacteria from the gut to the peritoneum without perforation. Occurs in ascites and alcoholics

How well did you know this?

Not at all

Perfectly

What is secondary peritonitis?

Where a perforation of the bowel causes bacteria in the bowel to spread to the peritoneum causing infection.
Post op or fistula

How well did you know this?

Not at all

Perfectly

Give an example of Spirochete shaped bacteria?

H pylori

How well did you know this?

Not at all

Perfectly

WHat are the 2 main groups of Enterobactericeae?

Lactose fermenting and non lactose fermenting.

How well did you know this?

Not at all

Perfectly

What are the common lactose fermenting enterobactericeae?

E coli
Klebsiella
Enterobacter
Serratia

How well did you know this?

Not at all

Perfectly

What are the common non lactose fermenting enterobactericeae?

Morganella 
Proteus 
Salmonalle
Shingella
Yersinis

How well did you know this?

Not at all

Perfectly

What is another name for Enterobacteriaceae?

Coliforms

How well did you know this?

Not at all

Perfectly

How long does it take for most microbiology results?

48 hours

How well did you know this?

Not at all

Perfectly

What do lactose fermentors do to McConkey agar?

Turn it pink

CLED agar is used to identify microbes in GI infections. T or F?

True

What are the characteristics of enterobacteriaceae?

``` Gram negative bacilli Non spore forming Ferment sugars mostly Mostly motile Mostly facultative anaerobes Increasing resistance ```

Which enterobacteriaceae are not motile?

Shingella and Klebsiella- DO not have flagella

Enterobacteriaceae have fimbrae. What are fimbrae and what are they used for?

Filamentous appendages, shorter than flagella. | Help with binding and adhesion to tissues and enterocytes

What is a enterotoxin?

a toxin produced in or affecting the intestines, such as those causing food poisoning or cholera eg Shiga toxin or shiga like toxin

What endotoxin do enterobacteriaceae have?

Lipopolysaccharide. When bacteria die the body is exposed to the LPS within the cell wall and this causes inflamation => gram negative sepsis

What causes oesophagitis in the immunosupressed?

Candida

If pancreatisis normally an infection problem?

Swarming on agar is characteristic of which bacteria?

Proteus sp | enterobacteriaceae, non lactose fermenting

Which organism is associated with petting zoos?

E coli 0157

What are the advantages and disadvantages of MALDI TOF?

+Analyse protein composition or bacterial cell wall + Quick + Discriminates between genetically similar organisms with identical 16s rRNA - Low specificity- hard to differentiate between pathogenic and non pathogenic e coli or salmonella and e coli - expensive Many tests in reference labs

What is serotype?

A serotype is a distinct variation within a species of bacteria

What is serotyping?

Identifying a particular type of bacteria using O (body antigens) and H (Flagella antigens)

WHat are the normal colonisers of the mouth?

Strep viridans (+ cocci) , Neisseria (- cocci), Candida, Staphylococci, anaerobes

What are the colinisers of the small bowel?

Small numbers of coliforms and anaerobes

What are the colonisers of the colon?

Large numbers of coliforms, anaerobes and Enterococcus faecalis.

What are the normal colonisers of the bile ducts?

Usually sterile

What are the anaerobes which grow in the GI tract?

Clostridium Bacteroides Anaerobic cocci

What is cholangitis?

AN infection in the common bile duct usually resulting from a gallstone

What is charcot's triad for cholangitis?

Fever RUQ pain Jaundice

When do you review empirical antibiotics?

After 48 hours at the latest. Should have the lab results.

When would OPHAT be considered in GI infection?

liver abscess as antibiotics for 6 weeks

What is used to treat an infection caused by enterococcus faecalis? What is the step down?

Amoxicillin (Vancomycin if penicillin allergic) Step down = oral switch to cotrimoxazole

Enterococcus faecium is more or less resistant and common than enterococcus faecalis?

Enterococcus faecium is more resistant and less common

Where do abscesses and infections i the liver come from?

Bile ducts- gallstones, malignancy, stricture Hepatic artery- bacteraemia Portal vein- bacteraemia, intra-abdominal infection, non metastatic colon cancer

What is the most important anaerobe in the gut?

Bacteriodes

What is sepsis?

Life threatening organ dysfunction caused by a dysregulated host response to infection

What is septic shock?

A subset of sepsis with circulatory and cellular metabolic dysfunction associated with a higher risk of mortality (essentially when fluid resuscitation does not work)

What are empirical antibiotics for peritonitis, bilary tract and intra-abdominal infection? and what is the step down?

IV ammoxicillin* (enterococci), metronidazole (anaerobes), gentamycin (enterobacteriaceae) *Vancamycin if penicillin allergic Step down = PO Cotrim and metronidazole

What gives a diagnosis of sepsis?

Infection with a NEWS score of 5+.

What are the components of Sepsis 6? | Give 3 take 3.

1) Blood cultures, other relevant cultures and U&Es. 2) Urine output- monitor hourly 3) Fluid resuscitation 4) Antibiotics IV 5) Lactate, FBC measurement 6) Oxygen- correct hypoxia

Why measure lactate in sepsis?

Measurement of tissue death. Raised lactate is a bad sign

How is a large abscess treated?

Surgery and drainage. | A large abscess has no blood supply and IV antibiotics will not penetrate it well.

What antibiotic is used if there are contraindications for gentamycin?

Aztreonam