Klebsiella, Enterobacter, Serratia (group K – E – S)

• What is the Gram stain result for the genus Klebsiella, Enterobacter, and Serratia?

  Gram -ve
• What type of sugar do Klebsiella, Enterobacter, and Serratia ferment?

  Lactose
• What color do colonies appear on MacConkey Agar for these genera?

  Pink
• What infections do Klebsiella, Enterobacter, and Serratia commonly cause?

  Pneumonia and UTIs
• Which of the following is non-motile: Klebsiella, Enterobacter, or Serratia?


  Klebsiella
• Which genus is encapsulated: Klebsiella, Enterobacter, or Serratia?


  Klebsiella
• What are the microbiological diagnosis methods for these genera?

  • Selective media: MacConkey, EMB Agar
  • Serological Tests
  • Antibiograms: high resistance
• What are the two strains of Klebsiella?

  1. Pneumoniae and K. Granulomatis
• What is the morphology of Klebsiella?

  Non-motile and urease +ve
• What type of colonies does Klebsiella produce?

  Very mucoid colonies
• What happens to eosin-methylene blue agar when Klebsiella ferments lactose?

  It turns purple
• What is the oxygen requirement for K. Granulomatis?

  Facultative anaerobe
• What is the reservoir for K. Pneumoniae?

  GI Tract Natural Flora
• What is the reservoir for K. Granulomatis?

  Genital Tract
• How is Klebsiella transmitted?

  Person-person and fecal-oral route
• What is a key virulence factor of Klebsiella?

  Capsular polysaccharide
• What does urease do in Klebsiella?

  Hydrolyzes urea to ammonia and CO2
• How does urease affect pH in Klebsiella infections?

  Increases pH to alkaline environment
• What are the clinical manifestations of K. Pneumoniae?

  • Nosocomial UTI
  • Aspiration pneumonia and lung abscess
  • Hepatic abscess
  • Kidney stones
• What are the clinical manifestations of K. Granulomatis?

  • Granuloma inguinale (STI)
  • Painless genital nodules
  • Ulceration to form beefy-red lesions
• What is the treatment for K. Pneumoniae?

  Fluoroquinolones or 3rd Generation Cephalosporins
• What is the treatment for K. Granulomatis?

  Azithromycin or Doxycycline
• What are the cultural features of Serratia?

  Catalase +ve and weakly ferments lactose
• What pigment does Serratia produce when cultured?

  Prodigiosin (red pigment)
• What are the reservoirs for Serratia?

  Animals, insects, plants, soil, water
• How is Serratia transmitted?

  Contact with contaminated sources
• What is a virulence factor of Serratia?

  Serralysin (protease enzyme)
• What does serralysin do?

  Causes tissue destruction and evades immune system
• What is the role of the exotoxin in Serratia?

  Induces high titres of antibodies
• What does the biofilm do for Serratia?

  Facilitates adhesion to surfaces
• What are the clinical manifestations of Serratia?

  • Pneumonia
  • UTI
  • Meningitis
  • Bacteraemia
  • Endocarditis
  • Wound infections
  • Ocular infections (e.g., keratitis)
• What is the treatment for Serratia infections?

  Aminoglycosides and antipseudomonal beta-lactam
• What is the treatment for meningitis caused by Serratia?

  3rd or 4th Generation Cephalosporins
• What is the treatment for multidrug-resistant Serratia infections?

  Carbapenems