L8: GNB 1 - Coliforms, Proteus, Pseudomonas Flashcards
What are enterobacterales?
gram negative bacilli
mostly live in intestine
most motile - have flagella
facultative anaerobes
What are the 3 antigens present in enterobacterales and where are they located?
O antigen = cell wall
H antigen = flagella
K antigen = capsule
List some of the virulence factors of enterobacterales
adhesins LPS capsules toxins antimicrobial resistance
What are some community-acquired infections that may occur as a result of non-toxin producing E. coli strains?
UTI
BSI
Intra-Abdominal Infection (cholecystitis, appendicitis)
Neonatal Meningitis
Pathogenic strains of E.coli may cause a UTI. Which virulence factor aids the pathogen in infecting the host?
Type 1 Fimbriae
Certain serotypes of E.coli are more commonly associated with UTIs. Which serotypes are these?
01, 02, 04
Many E.coli are resistant to which antibiotic?
amoxicilin
Which enterobacterales are lactose fermenters?
E. coli, Klebsiella spp.
Which enterobacterales are not lactose fermenters?
Proteus mirabilis
What type of pneumonia does Klebsiella pneumonia cause?
- necrotizing pneumonia (“red currant jelly” sputum)
- ventilator associated pneumonia
esp. affects alcoholics and the upper lobes of lungs
What are some characteritics of Proteus mirabilis?
- non lactose fermenter
- “swarming” on agar
- fishy smell
- often health-care associated infections
Proteus mirabilis may cause UTIs in which patients?
infection common in pts with urinary catheters
There is a high prevalence of ESBL produceres in which environment/location in Ireland?
nursing homes
In bacteria that has ESBL enzymes what would be the last resort antibiotic?
A Carbapenem - specifically, Meropenem
There are CPE organisms which are resistant to meropenem. They produce enzymes called carbapenamases which may be coded for by which genes?
IMP, KPC, OXA-48, NDM
Which CPE carbapenamase genes are the most common in Ireland?
KPC, OXA-48
VTEC is associated with which serotypes/strains of E.coli typically?
E.coli O157 or O26
In what vessel/organism is VTEC part of the normal flora?
Cows
How can VTEC be diagnosed?
PCR of stool - looking for verotoxin 1 or verotoxin 2
What is the treatment for VTEC? Why is the treatment preffered - what complications necessitate this treatment?
Treatment = supportive/rehydration
do not give antibiotics as this can precipitate Haemolytic Uraemic Syndrome (HUS)
List the virulence factors for pseudomonas spp.
pili flagellae polysaccharide capsule pyocyanin endotoxin - LPS
What is the function of pyocyanin?
impairs cilia
List some characteristics of pseudomonas aeruginosa
- non lactose fermenter
- strict aerobe
- oxidase positive
- forms biofilms
- in moist areas (sinks, drains…)
What type of infections can pseudomonas aeruginosa cause?
BSI (in burns patients)
Neutropenic Sepsis (haemotology/oncology pts)
Pneumonia (VAP)
UTI
Eye Infection
Ear Infection (otitis externa in swimmers + diabetics)
What is Burkholderia cepacia associated with?
opportunistic infection in lungs of CF patients
causes Cepacia Syndrome (acute fatal necrotizing pneumonia ± BSI)
What is Cepacia Syndrome?
caused by Burkholderia cepacia
acute fatal necrotizing pneumonia ± BSI
What pathogen causes melioidosis?
Burkholderia pseudomallei
What is the reservoir of burkholderia pseudomallei?
water (e.g. paddy fields)
Stenotyophomonas maltophilia may cause a BSI or pneumonia following what??
following prolonged broad-spectrum antibiotics
Which opportunistic pathogen can survive on wet/dry surfaces in hospitals? This pathogen is a/w injured soldiers returning from Iraq/Afghanistan.
Acinetobacter Baumanni
List 3 things/conditions that are a/w Haemolytic Uraemic Syndrome (HUS)
- Haemolytic Anaemia
- Acute Renal Failure
- Thrombocytopenia
