ENTEROBACTERIACIAE - GEN. CHARAC to SALMONELLA Flashcards
Facultatively anaerobic, non-spore-forming, Gram-negative bacilli
ENTEROBACTERIACEAE
All members (enterobacteriaciae) are motile at 35 degree cent. with peritrichous flagella except for…
Klebsiella, Shigella and Yersinia
All members (enterobacteriaciae) are non-encapsulated except for….
Klebsiella and Enterobacter
All members (enterobacteriaciae) ferment _____ (with acid production) and reduce ______
glucose ; nitrate to nitrite
All members (enterobacteriaciae) are gas producers except..
shigella (non-aerogenic)
most of them (enterobacteriaciae) are present in the intestinal tract as commensal except for..
Plesiomonas, Salmonella, Shigella, and Yersinia
enterobacteriaciae that may grow at 1-5 degree centigrade
Serratia and Yersinia
appearance of enterobacteriaciae in microscope
Gram-negative rods or coccobacilli with rounded ends
in BAP culture, enterobacteriaciae appear as a large, smooth, and gray except for ____ with mucoid colonies
Klebsiella and Enterobacter
in BAP culture, enterobacteriaciae are non-haemolytic except for some strains of _____, which are ____
E. coli ; β-haemolytic.
enterobacteriaciae (gen. characteristic) biochemical tests Catalase (+) except _____ and Oxidase (-) except for ____
s. dysenteriae ; Plesiomonas shigelloides
- Part of the intestinal microbiota of both humans and animals
- Generally do not initiate disease in healthy, uncompromised human hosts
- They produce signifant virulent factors
opportunistic pathogens
example of opportunistic pathogens
E.coli, Citrobacter, Enterobacter, Klebsiella, Proteus, and Serratia.
Acquired through ingestion of contaminated food or water.
Presence in specimen is considered as very significant
overt/true pathogens
overt/true pathogens examples
Salmonella, Shigella, and Yersinia pestis
___, _____, ____ are ESBL- producing enterobacteria
E. coli, K. pneumoniae, and K. oxytoca
are small proteins (enzymes) produced by bacteria, they can make the bacteria resistant to certain commonly used antibiotic medicines.
Extended-spectrum beta-lactamases (ESBLs)
_____, ____, ____ are isolated from the urinary tract and can cause bacteremia.
E. coli, P. mirabilis and K. pneumonia
_____, _____, _____ are antibiotic-resistant genera
Citrobacter, Enterobacter, and Serratia
____, ____, _____, ____ are associated with diarrhoea.
Shigella, Salmonella, E. coli and Yersinia
heat stable; located in the cell wall; used for E. coli and Shigella serotyping.
Somatic O antigen
heat labile; found in the flagellum; used for Salmonella serotyping.
Flagellar H antigen
heat labile; polysaccharide; found as K1 antigen of E. coli and Vi (virulence) antigen of Salmonella enterica serotype Typhi.
Capsular K antigen
bacteria that is associated with Bacteriuria, septicaemia, neonatal sepsis, meningitis, and diarrheal syndrome
e. coli
bacteria that is associated with Diarrhea, dysentery
shigella
bacteria that is associated with Diarrhea, wound infection, septicaemia, meningitis, and enteric fever
Edwardsiella
bacteria associated with septicemia, enteric fever, and diarrhea
salmonella
bacteria associated with opportunistic and nosocomial infections ( wound and urine)
citrobacter
bacteria associated with Bacteriuria, pneumonia and septicemia
klebsiella
bacteria associated with Opportunistic and nosocomial infection
morganella
bacterias that are associated with Opportunistic and nosocomial infections, wound infections, bacteriuria, and septicemia
enterobacter
serratia
proteus
providencia
bacteria associated with Plague
yersinia pestis
bacterias associated with Mesenteric adenitis, diarrhea
Yersinia pseudotuberculosis
Yersinia enterocolitica
bacteria associated with Wound that are contaminated with soil or vegetation
erwinia
Most significant species in the genus Escherichia and has the sex pili and adhesive fimbriae
E. coli
e. coli culture
MAC
BAP
EMB
in this culture, e.coli colonies appear flat and dry, and exhibit a pink color ( lactose fermenter or LF); some strains may be non-lactose fermenters or NLF.
mac
in this culture, e.coli Most strains are non- haemolytic; some strains are β-haemolytic
BAP
in this culture, e. coli exhibit a greenish metallic sheen
EMB
virulence factor of E. coli
Endotoxin, common pili, K1 antigen, and intimin
e. coli antigenic determinants
O, H, and K antigens
IMViC reaction of E.coli
+ + - -
TSIA reaction of E. coli
A/A ( acidic slant/acidic butt), (+) gas, (-) H2S
Primary indicator of fecal contamination in water purification and testing
Clin. Sig: major cause of UTI (90%), sepsis, meningitis in infants (also Grp B Strep), diarrheal diseases
E. coli
Classification of E. coli
ETEC
EIEC
EPEC
EHEC/VTEC
UPEC
-produces heat-labile (LT) and heat-stable (ST) enterotoxins
-causes Traveller’s diarrhea
Enterotoxigenic E. coli (ETEC)
-causes Shigella-like infection
-causes dysentery (bloody diarrhea; +WBC)
-(+) Sereny test
Enteroinvasive E. coli (EIEC)
-produces verocytotoxin
-causes nosocomial infection, infantile enteritis and diarrheal disease in children
-watery diarrhea with mucus but no blood
Enteropathogenic E. coli (EPEC)
- ingestion of poorly cooked meat
Enterohemorrhagic E. coli (EHEC)/ Verotoxic E. coli (VTEC)
shiga like toxin
verotoxin
most severe manifestation of Enterohemorrhagic E. coli (EHEC)/ Verotoxic E. coli (VTEC)
Hemolytic uremic syndrome (HUS)
Enterohemorrhagic E. coli (EHEC)/ Verotoxic E. coli (VTEC) complications
acute renal failure, thrombocytopenia, macroangiopathic hemolytic anemia
Enterohemorrhagic E. coli (EHEC)/ Verotoxic E. coli (VTEC) serotype
O157:H7
most common cause of UTI in humans
Uropathogenic E. coli (UPEC)
virulence factor of Uropathogenic E. coli (UPEC)
pili, cytolysins, aerobactin
Enterotoxigenic E. coli only grows on ___
BAP
E. coli 0157:H7 appears _____ on MAC and produces ____ growth.
colorless ; heavy
E. coli 0157:H7 rarely produces β-glucuronidase that results in a negative ______ test result
MUG (4-methylumbelliferyl-β-D-glucuronide)
similar to the Shiga toxin that is produced by Shigella dysenteriae 1.
Verotoxin I
causes damage to the kidney (Vero) cells of the African green monkey.
verotoxin
Formerly called E. coli atypical or enteric group H
Escherichia hermanii
Escherichia hermanii has been isolated from ___
CSF, wounds, and blood
Escherichia hermanii culture
yellow pigmentation
Usually found in the GIT of humans and animals and are non-motile
Klebsiella
Klebsiella species
K. pneumoniae, K. oxytoca, K. ozaenae, K. rhinoscleromatis and K. ornithinolytica.
Klebsiella culture
MAC (LF) – pink mucoid colonies
IMViC reaction of Klebsiella
– – + +
Klebsiella TSI reaction
A/A +gas
Most commonly isolated species of Klebsiella
Causative agent of a community-acquired pneumonia (mostly in immunocompromised host);
Afflicted patients cough up a “ currant jelly-like” sputum (dark-red sputum)
Klebsiella pneumoniae (Friedlander’s bacillus)
Klebsiella pneumoniae (Friedlander’s bacillus) virulence factor
Polysaccharide capsule
Klebsiella pneumoniae (Friedlander’s bacillus) culture
MAC – colonies exhibit a pink color and are mucoid ( LF)
Klebsiella pneumoniae (Friedlander’s bacillus) is positive on the ff test
Differential test: (+) string test
Neufeld-Quellung test: Positive
Reagent in string test of K. pneumoniae
0.5 Sodium deoxycolate
K. pnuemoniae growth on media with potassium cyanide (KCN):
positive
K. pneumoniae IMViC reactions
– – + +
K. pneumoniae TSIA reactions
A/A, (+) gas, (-) H2S
the causative agent of chronic atrophic rhinitis (purulent sinus infection) which is also known as the “foul-smelling” atrophic rhinitis
K. ozaenae
causes a granuloma of the nose and oropharynx.
K. rhinoscleromatis (Frisch bacillus)
Klebsiella that are both indole-positive.
K. oxytoca and K. ornithinolytica
Resemble those of Klebsiella when grown on a MacConkey agar.
Enterobacter
Enterobacter culture
MAC – colonies exhibit pink color and are sometimes mucoid (LF)
Enterobacter significant species
E. aerogenes, E. cloacae, E. gergoviae, and E. hormaechei
Enterobacter common isolates
E. aerogenes and E. cloacae
Enterobacter biochemical tests
Ornithine decarboxylase test : Positive
Lysine decarboxylase (LDC) test: Positive (except E. cloacae and E. gergoviae)
Growth on media KCN : Positive
Sorbitol fermentation: Positive ( E. aerogenes and E. cloacae)
Urease test: Positive ( E. cloacae)
Malonate test: Positive ( E. cloacae)
enterobacter IMViC reaction
– – + +
enterobacter TSIA reaction
A/A, (+) gas, (-) H2S
Found in respiratory samples and is rarely isolated from blood cultures.
Enterobacter gergoviae
Isolated with osteomyelitis following traumatic wounds and is formerly known as E. taylorae
Enterobacter cancerogenus
- Formerly known as Enterobacter sakazakii
-Found as contaminants of powdered infant formula
Cronobacter sakazakii
Cronobacter sakazakii is isolated from
Isolated from individuals with brain abscesses, and respiratory and wound infections.
Cronobacter sakazakii culture
a. MAC – colonies exhibit a pink color ( LF)
b. BHIA – colonies exhibit yellow pigmentation
Cronobacter sakazakii IMViC reaction
– – + +
Cronobacter sakazakii TSIA reaction
A/A, (+) gas, (-) H2S
- Formerly known as Enterobacter agglomerans
- Causes nosocomial outbreaks of septicaemia due to contamination of IV fluids
- Shows a triple decarboxylase negative reaction
Pantoea agglomerans
Pantoea agglomerans culture
MAC – colonies are clear or colorless (NLF)
Pantoea agglomerans IMViC reaction
– v + v
Pantoea agglomerans TSIA reaction
K/A ( Alkaline slant/ Acidic butt), (-) gas, (-) H2S
Opportunistic pathogens that are usually associated with nosocomial outbreaks
Resistant to a wide range of antibiotics
Serratia
Serratia culture
MAC – colonies are clear and colorless (NLF); some strains may show slow or late lactose fermentation.
serratia biochemical tests
(+) Dnase, gelatinase, lipase, and ONPG
serratia species
S. marcescens, S. odorifera, S. rubidaea, S. liquefaciens, and S. plymuthica
serratia IMViC reaction
– – + +
serratia TSIA reaction
K/A, (+) gas, (-) H2S
serratia specieis that produce pink to red colonies (due to the production of prodigiosin pigments) after incubation at 25 degree cent.
S. marcescens, S. rubidaea, S. liquifaciens, and S. plymuthica
serratia specie that has a musty and pungent odor or a “rotten potato-like” odor
S. odorifera
serratia specie that ferments arabinose and exhibits growth in a culture medium with KCN
S. liquefaciens
Most clinically significant species of the genus Serratia
Causes bacteremia outbreak in nurseries, cardiac surgery units, and burn units.
Few strains are late lactose fermenters
Serratia marcescens
Serratia marcescens biochemical test
(+) urease, gelatinase and ONPG; (-) arabinose fermentation
Species of this genus are isolated from urine, wound, and ear infection.
Can infect the proximal kidney tubule and can cause acute glomerulonephritis (AGN), particularly in patients with UTI and in catheterization.
Rapid urease producers
proteus
proteus species
P. mirabilis, P. vulgaris, P. penneri and P. myxofaciens
proteus human pathogens
P. mirabilis and P. vulgaris
common isolated proteus
p. mirabilis
proteus culture
MAC – colonies are clear and colorless (NLF): exhibit a “ swarming phenomenon” and have a “ burnt- chocolate” or “ burnt-gunpowder” odor.
exhibit a “ swarming phenomenon” and have a “ burnt- chocolate” or “ burnt-gunpowder” odor in mac culture
proteus
proteus PAD test
positive
P. mirabilis IMViC and TSIA reaction
P. mirabilis: - + v v
P.mirabilis: K/A, (+) gas, (+) H2S
P. vulgaris IMViC and TSIA reaction
P. vulgaris : + + - v
P. vulgaris: K/A, (+/-) gas, (+) H2S
Cause of nosocomial outbreaks involving burn units
Providencia
providencia species
P. alcalifaciens, P. stuartii, P. rettgeri, and P. heimbachae
providencia culture
MAC- colonies are clear and colorless (NLF)
providencia PAD test
positive
providencia IMViC reaction
+ + - +
providencia LIA reaction
R/A
providencia TSIA reaction
K/A, (-) gas, (-) H2S
Pathogen of the urinary tract
Also causes diarrheal disease among travellers
Mostly resistant to antimicrobial agents
Providencia rettgeri
Found in nosocomial outbreaks in burn units
Mostly resistant to antimicrobial agents
Providencia stuartii
Most commonly found in the feces of children with diarrhea.
Providencia alcalifaciens
Have the same biochemical reaction as those of P. vulgaris, except that the latter is citrate negative.
Morganella
morganella specie
Morganella morganii
morganella culture
MAC- colonies are clear and colorless (NLF)
Morganella PAD test:
Positive
Morganella IMViC reaction
+ + – –
Morganella LIA reaction:
R/A
Morganella TSIA reaction:
K/A, (+) gas,(-) H2S
Morganella is positive on the ff.
Urease, KCN, and ornithine decarboxylase
Species produce colonies in MacConkey agar that are similar to those of E.coli and have a biochemical resemblance to those of Salmonella.
Can cause false-positive agglutination test results with Salmonella.
Citrobacter
Citrobacter species grow in ___ agar
Simon’s Citrate
Citrobacter culture
MAC- colonies become clear and colorless (NLF) after 24 hours colonies exhibit a light pink color (LF) after 48 hours.
citrobacter species
C. freundii and C, koseri
citrobacter urease test
positive
citrobacter IMViC reaction
C. freundii : - + - +
C. koseri: + + - +
citrobacter TSIA reaction
C. freundii : A/A or K/A, (+) gas, (+) H2S
C. koseri: K/A, (+) gas, (-) H2S
- Can be isolated in diarrheal stool culture ( extraintestinal pathogen)
- Produces group 1 cephalosporinase
Citrobacter freundii
Causes outbreaks of neonatal meningitis and brain abscess in nursery units.
Citrobacter koseri (formerly C. diversus)
Most pathogenic enterobacteria that cause enteric fever (typhoid fever) and acute gastroenteritis ( food poisoning) to humans.
They are not part of the large intestinal microbiota
They may also be transmitted by human carriers
Salmonella
Salmonella mode of acquisition
Ingestion of contaminated animal food products or improperly cooked poultry, milk, eggs, and dairy; and direct human contact
salmonella species
S. enterica (human species) S. bongori (animal species)
salmonella virulence factors
Fimbriae and enterotoxin (S. enterica)
salmonella culture
MAC – colonies are clear and colorless (NLF)
SSA – Colonies are colorless with black centers.
salmonella antigenic structures
Somatic O and Flagellar H – for serologic grouping
Vi antigen (Salmonella serotype Typhi)- antiphagocytic
The main etiologic agent of enteric fever is ___
Salmonella serotype Typhi
The etiologic agents of paratyphoid fever are ____
Salmonella serotype Paratyphi A, b, and C, and Salmonella serotype Choleraesuis
Biochemical Characteristics of Salmonella species
All species are motile except for Salmonella serotype Pullorum and Salmonella serotype Gallinarum
All species produces gas except for Salmonella serotype Gallinarum and Salmonella serotype Typhi.
All species produces H2S except for Salmonella serotype Paratyphi A
LDC: Positive ( except for Salmonella serotype Paratyphi A)
Urease: Negative
Growth on media with KCN: Negative
All salmonella species are motile except for
Salmonella serotype Pullorum and Salmonella serotype Gallinarum
All salmonella species produces gas except for
Salmonella serotype Gallinarum and Salmonella serotype Typhi.
All salmonella species produces H2S except for
Salmonella serotype Paratyphi A
salmonella is LDC positive except for
Salmonella serotype Paratyphi A
salmonella is negative on ..
urease and growth on media with KCN
salmonella IMViC reaction
– + – +
Salmonella serotype Typhi IMViC reaction
– + – –
salmonella TSIA reaction
K/A, (+) gas, (+) H2S
Salmonella serotype Typhi TSIA reaction
K/A, (-) gas, (+) H2S
