PSEUDOMONAS

• Enterobacteriaceae


  Gram (-) rods, motile with peritrichous flagella or nonmotile

  
• Enterobacteriaceae

  • Escherichia coli
  • Serratia marcescens
  • Proteus spp.
  • Klebsiella pneumoniae
  • Salmonella spp.

  
• Enterobacteriaceae


  • (+) growth on peptone or meat extract media without the addition of sodium chloride
  • (+) Growth MacConkey agar
  • Facultative anaerobe
  • Glucose fermenter (with gas production)
  • (+) Catalase
  • (-) Oxidase
  • Can reduce nitrate to nitrite
• Lactose Fermenter


  Able to ferment lactose
• Lactose Fermenters

  • Escherichia coli
  • Klebsiella pneumoniae
  • Salmonella

  
• Escherichia coli


  Encapsulated and motile<|>Facultative anaerobe<|>Certain strains are beta-hemolytic on blood agar<|>Fast lactose fermenter; (+) Beta-galactose (it has the ability to break down lactose into glucose and galactose)<|>Non-fastidious<|>(+) Catalase
• Escherichia coli natural reservoir

  Intestine and Vagina
• Escherichia coli mode of transmission

  Person to person contact<|>Contaminated food or water<|>Dislocation from the intestinal tract

  
• Escherichia coli forms colonies with a green metallic sheen in Eosin-Methylene Blue (EMB) agar

  
• Escherichia coli


  • Associated with urinary tract infection for young women (most common cause of UTI is e-coli)
  • E-coli associated diarrheal disease
  • Neonatal meningitis (2nd most common cause worldwide, 1st in the Philippines)

  
• Escherichia coli virulence factors

  • Fimbriae (cystitis, pyelonephritis)
  • K-capsule (pneumonia, neonatal meningitis)
  • Lipo-polysacchardie endotoxin LPS (septic shock)

  
• Escherichia coli serotypes

  O antigen (somatic antigen) lipopolysaccharide. Consists of repeating units of polysaccharide. Resistant to heat and alcohol<|>K antigen (capsular antigen), Human infections of the respiratory tract are caused particular by capsular types 1 and 2, and for the Urinary Tract: Types 8, 9, 10, 24<|>H antigen (flagellar antigen) It is located on flagella and are denatures or removed by heat and alcohol<|>F antigen (fimbrial antigen)

  
• Escherichia coli pathotypes

  EHEC/STEC - Enterohemorrhagic E.coli (Bloody diarrhea without pus and fever, Hemolytic uremic syndrome)<|>ETEC - Enterotoxigenic E. coli (Causes traveler's diarrhea, Important cause of diarrhea in children age <5 years in developing countries, Rice water like stool (like cholera))<|>EIEC - Enteroinvasive E.coli (Invades the intestinal mucosa causing necrosis and inflammation, Bloody diarrhea with pus in stool and fever (similar to shigellosis/ dysentery))<|>EPEC - Enteropathogenic E.coli (Important cause of diarrhea in infants, especially in developing countries, Severe watery diarrhea, vomiting, and fever, which are usually self-limited but can be prolonged or chronic)<|>EAEC - Enteroaggregative E.coli (Causes acute and chronic diarrhea in persons in developing countries, Cause of foodborne illnesses in industrialized countries, Associated with traveler's diarrhea and persistent diarrhea in patients with HIV)<|>UPEC - Uropathogenic E.coli (Causes 50% of hospital acquired UTI and 90% of community acquired UTI, Can also cause cystitis and pyelonephritis)

  
• Nonpathogenic Escherichia colo (normal flora) + Virulence Factor = Disease

  
• Escherichia coli treatment

  • Oral rehydration salts
  • Third generation cephalosporins
  • Fluoroquinolones
  • Doxycyline
  • Cotrimoxazole
  • Trimethroprim-Sulfamethoxazole
• Do not give anti-motility agents especially for pedia gastroenteritis
• Treatment for hemolytic uremic syndrome

  • Dialysis
  • Corticosteroid
  • Blood transfusion
  • Plasma pheresis

  
• Treatment for UTI

  • Co-trimoxazole
  • Nitrofurantoin
  • Fluoroquinolones
  • Ciprofloxacin
• Escherichia coli can cause diarrhea indistinguishable from shigellosis and cholera caused by shigella spp, and vibrio cholerae

  
• Klebsiella pneumoniae

  Causative agent of infections usually occur in immunocompromised individuals<|>3rd most common cause of UTI<|>Grows well in MacConkey Agar<|>Major cause of hospital acquired infections<|>Facultative anaerobes<|>Non motile<|>Possesses prominent polysaccharide capsule<|>Beta-lactamase positive<|>Urease positive<|>Lactose fermenter<|>Iron uptake system<|>Part of the normal flora of the human mouth and intestine

  
• Klebsiella pneumoniae

  Commonly associated with nosocomial pneumonia and nosocomial urinary tract infection

  
• Klebsiella pneumoniae virulence factors

  • Polysaccharide capsule
  • Pili
  • Lipopolysaccharide (LPS)
  • Siderophore

  
• Klebsiella pneumoniae urinary tract infections

  Ability to convert urea present in the urine to CO2 and ammonia leading to the formation of struvite stones

  
• Klebsiella pneumoniae hospital-acquired infections risk factors

  • Diabetes and Alcoholism (usually cause lobar pneumonia - causes formation of lung abscess due to aspiration of the microbe in the oropharynx of the LRT)
  • Central Venous Catheters (CVC) - bacteremia leading to endocarditis and meningitis
  • Endotracheal Tubes
  • Urinary Catheters - UTI, pyelonephritis

  
• Klebsiella pneumoniae diagnosis

  • Blood, sputum, or urine cultures
  • Chest x-ray (pneumoniae - cavitary lesions in upper lobes if there is an abscess formation)
  • Alkaline urine (<pH 7)
  • Pyuria (increased WBC in urine)
  • Bacteriuria
  • Leukocytosis (increased WBC count)

  
• Klebsiella pneumoniae treatment

  • Cephalosporins
  • Aminoglycosides
  • Fluoroquinolones
  • Carbapenems
  • Colistin
  • Fosfomycin
  • Tigecycline

  
• Klebsiella pneumoniae mnemonic

  GET UPS you FAT ALCOHOLIC!<|>GET UP: non-motile<|>U: Urinary Tract Infection<|>P: Pneumonia<|>S: Sepsis<|>FAT: Fat Capsule<|>Alcohol: Alcoholic and Nosocomial patients
• Serratia marcescens

  Opportunistic microorganism<|>Motile<|>Facultative anaerobic<|>Urease (+)<|>Catalase (+)<|>Slow lactose fermenter<|>Prodigiosin (+) - red pigment, not all strains can produce this
• Serratia marcescens natural reservoir

  Water and soil surfaces
• Serratia marcescens virulence factors

  • Fimbriae - has the ability to attach to host cells
  • Hemolysin - can destroy RBC
  • Formation of adherent biofilms in medical equipment - such as IV catheters and even contact lenses

  
• Serratia marcescens hospital-acquired infections

  • Pneumonia (patients that are mechanically ventilated)
  • Urinary Tract Infections (urinary catheters)
  • Bacteremia or Sepsis leading to endocarditis (blood vessel catheters)
  • Meningitis or cerebral abscesses (neurological instrumentation)
  • Cellulitis, fasciitis, and myositis, skin abscesses (wound or surgical wounds)
  • Conjunctivitis or keratitis (contact lenses)

  
• Serratia marcescens diagnosis

  • Blood/ Sputum/ Urine/ CSF Culture
  • Bacteriuria and Pyuria
  • Pneumonia (Chest X-ray)
  • CNS Infections (Brain CT Scan and Lumbar Puncture)

  
• Serratia marcescens treatment

  • Aminoglycosides + Antipseudomonal beta-lactam (Piperacillin + Tazobactam, Ticarcillin + Clavulanate)
  • Fluoroquinolones or Carbapenems (when infection persists)
• Proteus mirabilis


  Common cause of community acquired nosocomial UTIs<|>Highly motile (swarming motility)<|>Facultative anaerobic<|>Swarming growth in discontinuous manner on agar<|>Non-lactose fermenter<|>H2S (hydrogen sulfide) (+) on TSI (tripe sugar iron) agar containing lactose, glucose, and sucrose + iron & a pH sensitive dye<|>Fishy odor (+) in agar<|>Urease (+)<|>Grows well on blood agar and Mac Conkey agar<|>Natural reservoir: soil, water, intestinal flora<|>Resistant to polymyxin and tetracyclines

  
• Proteus mirabilis TSI agar results
• Proteus mirabilis virulence factors

  • Flagella
  • Fimbriae
  • Hemolysin
  • ZapA protease
  • Urease
• Proteus mirabilis urinary tract infections

  • Urethritis
  • Cystitis
  • Prostatitis
  • Pyelonephritis
  • Xanthogranulomatous pyelonephritis

  
• Proteus mirabilis UTI risk factors

  • Hospitalization
  • Multiple prior UTIs
  • Urinary Tract surgery
  • Neurogenic bladder
  • ↑ age (most common in elderly)
  • Prior use of antibiotics
  • Urinary catheterization
  • Frequent sexual activity
  • Structural abnormalities in the urinary tract
• Proteus mirabilis


  Common cause of community acquired and nosocomial UTIs
• Proteus mirabilis

  • Highly motile (swarming motility)
  • Facultative anaerobic
  • Swarming growth in discontinuous manner on agar
  • Non-lactose fermenter
  • H2S (hydrogen sulfide) (+) on TSI (triple sugar iron) agar containing lactose, glucose, and sucrose + iron & a pH sensitive dye
  • Fishy odor (+) in agar
  • Urease (+)
  • Grows well on blood agar and Mac Conkey agar