Lecture #14: Klebsiella, Enterobacter, Citrobacter

T/F: Klebsiella is belong to Enterobacteriaceae

True

Klebsiella:

1. Gram _

2. Motility

3. Special enzymes?

4. Agar colony description?

1. Gram -

2. Non-motile

3. Urease positive

4. Mucoid

What are the Virulence factors associated with Klebsiella?

1. Capsule

2. Adhesin

3. Endotoxin (Coliform septicemia)

4. Urease

K. pneumoniae and K. oxytoca cause __________ infections

Opportunistic (they both are naturally found on animals but only cause disease in certain scenarios)

K. pneumoniae can cause Bovine ______, T/F: it cause this in many animals across the entire heard

• Mastitis

• False, it is usually associated with individual cases

What part of the environment of a dairy barn is Klebsiella associated with?

• Sawdust and shavings

  • These are the normal sources of Klebsiella, when they get moist it creates an ideal environment

Which species of animals can Klebsiella infect? How does it infect them?

1. Equine

   1. Colonizes the lower reproductive tract of mares

      1. Vaginitis, metritis, infertility, abortion (repro related issues)

2. Canine

3. Companion Birds

   1. Contaminant of bird seeds

   2. Colonizes the cloaca and choana of healthy birds

   3. Causes

      1. Septicemia, respiratory signs, diarrhea

T/F: Stallions are reservoirs for K. pneumoniae/oxytoca

False, they can get infected and transmit but are not reservoirs

What is the most common infection site of Klebsiella in humans?

The urinary track

T/F: Klebsiella can be seen in reptiles

True

Enterobacter:

• Gram_

• Motility?

Enterobacter are Gram - and Motile

What are the 2 main species of Enterobacter to know?

1. Enterobacter cloacae complex

2. E. hormaechei

T/F: Both Klebsiella and Enterobacter are motile

False, Klebsiella is non-motile

Enterobacter are known to to have an innate ________ ________, what causes this?

Antimicrobial resistance, Beta-lactamase

What is the significance of Enterobacter in humans?

Common cause of nosocomial infections in health care facilities

What species of Citrobacter is known to infect turtles? What does it cause?

• Citrobacter Freundii

  • Septicemia cutaneous ulcerative disease (SCUD)

What disease does Citrobacter rodentium cause in rodents?

• Murine Colonic Hyperplasia (Image)

• C.S

  • Diarrhea, rectal prolapse

  • Effacement of the brush-border 

What are the 2 main species of Proteus that we discuss? Are either strains associated with a particular disease process?

1. Proteus mirabilis 

   1. Common cause of UTIs

2. Proteus vulgaris

T/F: Proteus is urease negative

False, it is Urease positive

Proteus infections are a common cause of ____

UTIs

Proteus mirabilis performs “swarming. “What does this mean?

• The coordinated, rapid movement of a bacterial population across a solid surface

• Results in the formation of the odd shaped proteus colonies (circular)

__________ is the hallmark of a Proteus infection, how does Proteus cause this?

• Urolithiasis (Struvite formation) 

  • Urease (converts urea to CO2 and urine, increases pH, causes formation of struvites)

What are Superbugs?

Strains of bacteria that are resistant to several classes of antibiotics (multi- or pan- resistant)

Based on the growth on a BA plate, which of the bacteria that are in this Knowt (Klebsiella, Enterobacter, Citrobacter, Proteus) is this?

Proteus

What are the superbug species? (Use hint)

• Enterococcus faecium

• Staphylococcus aureus

• Klebsiella species

• Acinectobacter baumanni

• Psuedomonas aeruginosa

• Enterobacter spp.

What relationship do Hospitals have with Superbugs?

They are a breeding ground for Superbugs

How do superbugs resist the drugs that normally work to treat them?

• They secrete Extended-spectrum beta-lactamases (ESBLs)

  • ESBL enzymes break down penicillins and cephalosporins

List the predisposing factors of Klebsiella-associated mastitis

Moist/wet sawdust and/or shaving bedding

T/F: Klebsiella, Morganella, and Enterobacter spp. cause opportunistic infections

True

Klebsiella-associated bacterimia can lead to which clinical/pathological condition?

Endotoxemia?

Citrobacter infection is a problem in which animal species?

Reptiles (C. freundii) and Rodents (C. rodentium)

List the virulence factors of Proteus

• Endotoxin (Urease)

• IgA protease

• Fimbriae

• Swarming Motility

• Hemolysins

What is the advantage of the urease enzyme for a pathogen?

It allows it to survive in the Urinary tract and utilize urea to survive (decreases the pH to make the environment habitable)

How uroliths are formed in Proteus infected bladder?

1. Urease hydrolyzes Urea → Ammonia + CO2

2. Ammonia damages urinary epithelium

3. Urinary pH increases

4. Precipitate ions form calculi in the form of struvites

T/F: In bladder infections, bacteria can hide in struvites

True