Mod 6

• GROUPS OF ENTEROBACTERIA

  • OPPORTUNISTIC PATHOGENS
  • OVERT/TRUE PATHOGENS
• OPPORTUNISTIC PATHOGENS


  They are part of the intestinal microbiota of both humans and animals<|>They generally do not initiate disease in healthy, uncompromised human hosts<|>They may produce serious infection outside their normal body sites (extraintestinal infection)
• OVERT/TRUE PATHOGENS


  They are not present as commensal microbiota of the human GIT<|>They are acquired through ingestion of contaminated food or water<|>Their presence in any specimens is considered very significant<|>They produce significant virulent factors
• OPPORTUNISTIC PATHOGENS

  • E. coli
  • Citrobacter
  • Enterobacter
  • Klebsiella
  • Proteus
  • Serratia
• OVERT/TRUE PATHOGENS


  • Salmonella
  • Shigella
  • Yersinia
  • Plesiomonas shigelloides
• Medically Important Gram-negative Bacilli

  • Glucose Fermenting
  • Glucose Non-fermenting
• Glucose Fermenting

  • Oxidase positive
  • Oxidase negative
• Oxidase positive

  • Pasteurella spp.
  • Vibrio spp.
  • Aeromonas spp.
  • Pleisiomonas spp.
• Oxidase negative

  • Enterobacteriaceae
• Enterobacteriaceae


  • Lactose-fermenting
  • Non-lactose fermenting
• Lactose-fermenting

  • E.coli
  • Citrobacter spp.
  • Klebsiella spp.
  • Enterobacter spp.
  • Serratia spp.
• Non-lactose fermenting

  • Morganella spp.
  • Proteus spp.
  • Providencia spp.
  • Salmonella spp.
  • Shigella spp.
  • Yersinia spp.
• Glucose Non-fermenting

  • Non-lactose fermenting
  • Oxidase positive
  • Oxidase negative
• Oxidase positive

  • Pseudomonas spp.
• Oxidase negative

  • S. maltophilla
  • A. baumanni
  • B. cepacia
• SPECIMEN TYPE

  • BLOOD
  • RESPIRATORY SAMPLES
  • URINE
  • WOUND DISCHARGE
  • OTHER BODY FLUIDS
  • CSF
• In 2020, a taxonomy change was adopted to use "Enterobacterales" as the name of a new scientific order. "Enterobacteriaceae " are now a family within the "Enterobacterales" order, along with Erwinaceae, Pectobacteriaceae, Yersiniaceae, Hafniaceae, Morganellaceae, and Budvicaceae.
• PRESUMPTIVE IDENTIFICATION

  • Large, dull gray, dry or mucoid colonies on sheep blood agar
  • LF =Colonies that appear red or pink on MAC
  • LF =Colonies that appear green sheen on EMB
  • Some species have distinctive pigmentation and odor
  • Variable and indistinctive hemolysis on blood agar
  • Nitrate reducer
  • Cytochrome Oxidase negative
  • Glucose fermenters
• All Enterobacterales have similar microscopic morphology; therefore, Gram staining is not significant for the presumptive identification of Enterobacterales.

  
• Generally, isolation of gram-negative organisms from a sterile site, including CSF, blood, and other body fluids, is critical and may assist the physician in prescribing appropriate therapy
• PRIMARY ISOLATION MEDIA

  • ENRICHMENT BROTH
  • SELECTIVE OR DIFFERENTIAL
  • NONSELECTIVE
• Media of Choice

  • SELECTIVE AGAR
  • Hektoen enteric (HE)
  • Xylose-Lysine Deoxycholate (XLD)
  • Salmonella-Shigella Agar (SSA)
  • Gram Negative Broth (GN)
  • Selenite Broth (SEL)
  • CHROMagar Salmonella
  • Brilliant Green Agar
  • Bismuth sulfite agar
  • Cefsulodin-Irgasan-Novobiocin Agar (CIN)
  • MacConkey Sorbitol Agar (MAC-SOR)
• LACTOSE FERMENTERS

  • POSITIVE
  • Enterobacter spp.
  • POSITIVE
  • Salmonella spp.
  • LYSINE DECARBOXYLASE
  • POSITIVE
  • Salmonella spp.
  • Citrobacter spp.
  • NEGATIVE
  • E. coli
  • NEGATIVE
  • E. Coli
  • Klebsiella spp.
  • Enterobacter spp.
  • MOTILITY
  • NEGATIVE
  • C. freundii
  • HYDROGEN SULFIDE
  • NEGATIVE
  • Klebsiella spp.
  • POSITIVE
  • Klebsiella spp.
  • Enterobacter spp.
• Klebsiella spp.

  • Klebsiella pneumoniae subsp. pneumoniae
  • K. aerogenes
  • K. pneumoniae subsp. rhinoscleromatis,
  • Klebsiella oxytoca
  • K. pneumoniae subsp. ozaenae
  • Klebsiella quasipneumoniae
  • Klebsiella variicola
• Biochemical Test

  • K. pneumoniae
  • K. oxytoca
  • Roultella ornithinolytica
  • K. ozanae
  • K. rhinoscleromatis
  • K. aerogenes
• Enterobacter spp., Pantoea agglomerans & Hafnia alvei

  • INDOLE
  • POSITIVE
  • E. sakazakii
  • NEGATIVE
  • E. agglomerans
  • E. cloacae
  • E. gergoviae
  • Hafnia alvei
  • POSITIVE
  • E. Agglomerans
  • E. sakazakii
  • NEGATIVE
  • E. Agglomerans
  • E. sakazakii
  • POSITIVE
  • E. gergoviae
  • Hafnia alvei
  • NEGATIVE
  • E. cloacae
  • SORBITOL
  • ARGININE +ORNITHINE
  • LDC
  • POSITIVE
  • NEGATIVE
  • E. gergoviae
  • Hafnia alvei
  • ARGININE +ORNITHINE
  • POSITIVE
  • E. gergoviae
  • NEGATIVE
  • Hafnia alvei
• Biochemical Test

  • E. cloacae
  • Cronobacter (E. sakazakii)
  • Pantoea (Enterobacter) agglomerans
  • E. gergoviae
  • Hafnia alvei
• ISOLATION AND IDENTIFICATION OF NON-LACTOSE FERMENTERS

  • HYDROGEN SULFIDE (+)
  • Proteus spp.
  • Salmonella spp.
  • POSITIVE
  • Proteus spp.
  • NEGATIVE
  • P. mirabilis
  • Citrobacter spp.
  • E. Tarda
  • E. coli
  • NEGATIVE
  • Salmonella spp.
  • Citrobacter spp.
  • E. Tarda
  • E.coli
  • LYSINE DEAMINASE
  • INDOLE
  • POSITIVE
  • P. vulgaris
  • SALMONELLA TYPING
  • CITRATE
  • POSITIVE
  • Salmonella spp.
  • NEGATIVE
  • Citrobacter spp.
  • E. Tarda
  • E.coli
  • POSITIVE
  • Citrobacter spp.
  • NEGATIVE
  • E. Tarda
  • E.coli
  • LYSINE DECARBOXYLASE
  • POSITIVE
  • C. freundii
  • ONPG, MANNITOL
  • POSITIVE
  • E. coli
  • NEGATIVE
  • E. Tarda
• H2S NEGATIVE NON-LACTOSE FERMENTERS


  • Salmonella spp.
  • Shigella spp.
  • E.Coli
  • Klebsiella spp.
  • Enterobacter spp.
  • Serratia marcescens
  • NEGATIVE
  • NEGATIVE
  • NEGATIVE
  • LYSINE DEAMINASE
  • Salmonella spp.
  • Shigella spp.
  • Proteus-Providencia-Morganella gp (PPM)
  • Shigella spp.
  • E. coli
  • Klebsiella spp.
  • Enterobacter spp.
  • Serratia marcescens
  • HYDROGEN SULFIDE NEGATIVE
  • SHIGELLA TYPING
  • PPM POSITIVE
  • CITRATE
  • E. coli
  • POSITIVE
  • MOTILITY
  • POSITIVE
  • E.Coli
  • Salmonella spp.
  • Enterobacter spp.
  • Serratia marcescens
  • Salmonella spp.
  • Enterobacter spp.
  • Serratia marcescens
• PPM

  • H2S (+); DEAMINASE (+); MR(+)/VP(-);UREASE (+)
  • Proteus vulgaris, P. hauseri, P. mirabilis, P. penneri;
  • Morganella morganii, M. siboni
  • P. mirabilis
  • P. penneri
  • NEGATIVE
  • NEGATIVE
  • NEGATIVE
  • NEGATIVE
  • P. penneri
  • INDOLE
  • POSITIVE
  • P. vulgaris
  • M. morganii
  • M. siboni
  • NEGATIVE
  • M. morganii
  • H2S (+)
  • UREASE (+)
  • TREHALOSE
  • P. hauseri
  • M. siboni
  • POSITIVE
  • MALTOSE
  • P. hauseri
  • POSITIVE
  • MALTOSE
  • P. vulgaris
  • POSITIVE
  • ORNITHINE
  • P. mirabilis
• Biochemical Test

  • P. hauseri
  • P. vulgaris
  • P. mirabilis
  • P. penneri
  • P. myxofaciens
• Morganella spp., proteus spp. & Providencia spp.

  • BIOCHEMICAL TEST
  • M. morganii
  • PROTEUS
  • PROVIDENCIA
  • P. vulgaris
  • P. mirabilis
  • P. alcalificiens
  • P. stuartii
  • P. rettgeri
• NOTES TO REMEMBER

  • UTI
  • Agents of Bacteremia
  • Associated with diarrhea
  • Antibiotic-resistant genera
  • ESBL-producing enterobacteria
• Biochemical Test

  • TSI
  • Gas
  • H2S
  • Indole
  • MR
  • VP
  • Citrate
  • PAD
  • Urease
  • Motility
  • LDC
• Organisms

  • K. oxytoca
  • K. pneumoniae
  • Enterobacter
  • P. Mirabilis
  • Shigella
  • Salmonella
  • Serratia
  • Citrobacter
  • Yersinia
• TSI

  Triple Sugar Iron Agar
• TSI test results

  • Gas
  • H2S
  • Indole
  • MR
  • VP
  • Citrate
  • PAD
  • Urease
  • Motility
  • LDC
• Salmonella serotype Typhi
• Shigella dysenteriae
• S. sonnei