1
Q
• Gram-negative bacilli
• Facultative anaerobes
• All species ferment glucose with the production of acid or acid and gas
• All are motile at 35oC with peritrichous flagella (except for _______, ______ and _______)
• Catalase positive (except for _________________ which is catalase-negative)
• Oxidase-negative (except for ___________)
• Non encapsulated (except for _________ and
___________)
• Non-spore forming
• Reduce nitrate to nitrites (except for _________ and __________)
• Most are commensal of the GI tract (except for
_________, _________, ________ and _________)
• Serratia and Yersinia may grow at 1oC to 5oC
• They do not produce cytochrome oxidase except for Plesiomonas
A
- ENTEROBACTERIACEAE
- Klebsiella, Shigella and Yersinia
- Shigella dysenteriae type 1
- Plesiomonas
- Klebsiella and Enterobacter
- Photorhabdus and Xenorhabdus
- Plesiomonas, Salmonella, Shigella and Yersinia
2
Q
• __________ - Gram-negative coccobacilli or straight-rods
• _____________ – no value for initial identification
A
- Gram-stain
- SBA or CAP (Chocolate Agar Plate)
3
Q
- EMB (Eosin-Methylene Blue)
- MAC (Macconkey agar)
- HEA (Hektoen Enteric Agar), XLD (XyloseLysine Desoxycholate) – highly selective
A
Differential and Selective Media
4
Q
• Several selective and differential media used to isolate distinguishes between LF & LNF
- Enterics are classified on the basis of lactose
fermentation; the lactose fermenters and the
non-lactose fermenters
A
CLASSIFICATION – BASED ON LACTOSE
FERMENTATION
5
Q
The most important media are:
A
- MacConkey agar
- Eosin Methylene Blue (EMB) agar
- Salmonella Shigella (SS) agar
- Triple Sugar Iron (TSI) agar
6
Q
Enterobacteteriaceae
A
- Lactose fermenters E. coli, Citrobacter, Klebsiella, Enterobacter
- Non-lactose fermenter Salmonella, Shigella Proteus, Yersinia
7
Q
• A pink colony appearance when lactose are
fermented and a colorless appearance in nonlactose fermenting organisms
A
MacConkey Agar
8
Q
• Escherichia coli
• Klebsiella
• Enterobacter
• Serratia (except S. fonticola) – SLOW or LATE
• Citrobacter – SLOW or LATE
• *Coliform bacilli – Escherichia, Klebsiella, Enterobacter and Citrobacter
- The most common member is the colon bacillus or the Escherichia coli
A
Lactose Fermenter
9
Q
• Proteus
• Morganella
• Providencia
• Hafnia
• Edwardsiella
• Salmonella
• Shigella (except S. sonnei – “Late” LF)
• Yersinia
A
Non-Lactose Fermenter
10
Q
• The ____________ are often a part of the usual intestinal microbiota of both humans and animals
- However, outside their normal body sites, these organisms can produce serious extraintestinal,
opportunistic infections, Other organisms can be equally devastating in immunocompromised hosts or when introduced to wounds from contaminated soil or water.
A
Opportunistic pathogens
11
Q
• Plesiomonas, Salmonella, Shigella and Yersinia
• Not present as commensal biota in the GI tract of humans
- The primary pathogens, which include S. enterica, Shigella spp., and Yersinia spp., are considered true pathogens; that is, they are not present as commensal biota in the Gastrointestinal tract of humans. hese organisms produce infections resulting from ingestion of contaminated food or water or from other sources
A
Primary pathogens
12
Q
- The _________ of the Enterobacteriaceae genera is affected by many factors, such as the ability to adhere, colonize, produce toxins, and invade tissue
A
VIRULENCE AND ANTIGENIC FACTORS
13
Q
• _____________ – this is a heat-stable antigen located on the cell wall.
• ____________ – this is a heat-labile antigen found on the surface of flagella, structures responsible for motility.
• ____________ – this this is a heat-labile polysaccharide found only in certain encapsulated species
A
- O antigen (somatic antigen)
- H antigen (flagellar antigen)
- K antigen (capsular antigen)
14
Q
• ________ – E. coli
• ________ – Salmonella enterica subsp. enterica serotype Typhi.
A
- K1 antigen
- Vi antigen
15
Q
• Historically the identification of bacteria has been based on colony morphology gram staining and biochemical testing
• Biochemical testing was originally done in test
tubes. The most accurate are the biochemical test but it requires a lot of time to inoculate the multiple tubes of media and need a lot of space in the incubator.
• Overtime, biochemical test were miniaturized and multi-test system were developed, resulting in saving of time and space
• Automated system are also available and usually used especially in different countries
A
MEDIA AND TESTS USED FOR THE IDENTIFICATION OF ENTEROBACTERIACEAE
16
Q
________________ – to detect the production of hydrogen sulfide H2S (black precipitate in the medium)
A
Ferrous sulfate and sodium thiosulfate are added
17
Q
_______________ is a similar medium, but only incorporates the carbohydrates glucose and lactose.
A
Kligler’s iron agar (KIA)
18
Q
_____________ – Alkaline slant/alkaline butt (ALK/ALK or K/K) or alkaline slant/no change (ALK/no change or K/NC) –Red/Red
A
No fermentation
19
Q
_________________ – Alkaline slant/acid butt or K/A –Red/Yellow
A
Glucose fermentation only, no lactose (or sucrose in TSI) fermentation
20
Q
______«< – blackening of the medium
A
H2S production
21
Q
___________________ – formation of bubbles or splitting of the medium from the bottom of the tube
A
Gas production (aerogenic) or no gas production (nonaerogenic)
22
Q
• Indole Test
• Methyl Red Test
• Voges-Proskauer Test
• Citrate Utilization Test
A
IMVIC REACTIONS
23
Q
• Test the ability of the bacteria to produce the enzyme tryptophanase and deaminate tryptophan to indole, pyruvic acid, and ammonia
A
Indole Test
24
Q
Two reagents can be used:
A
- Ehrlich’s reagent – more sensitive
- Kovac’s reagent
25
- Indole s one of the degradation products of the amino acid tryptophan. Organisms that possess the enzymes tryptophanase are capable of deaminating tryptophan with the formation of intermediate degradation products of indole, pyruvic acid in ammonia
Positive reaction – pink/red
26
- If glucose is metabolized by the mixed acid fermentation pathway, stable acid end products are produced, which results in a low pH
Methyl Red Test
27
• ___________ – remain yellow after addition of MR pH indicator
• __________ – red color after addition of MR pH indicator
- Negative reaction
- Positive reaction
28
- It measure the production of acetoin after the addition of α-naphthol (catalyst or color intensifier) followed by 40% KOH or NaOH
Voges-Proskauer Test
29
• It determines whether an organism can use sodium citrate as a sole carbon source
Citrate Utilization Test
30
• __________ – Simmons’ Citrate Medium (SCA) – routinely used
• __________ are the nitrogen source in the medium and utilization of these salts results in the release of ammonia, causing a pH change
• __________ – bromthymol blue
- Medium used
- Ammonium salts
- pH indicator
31
It detects the ability of an organism to utilize
citrate as the sole source of carbon and energy
are inoculated on a medium containing sodium
citrate and a Ph indicator bromthymol. The
medium also contains inorganic ammonium
salts which is utilized as the sole source of
nitrogen
Positive reaction – blue
32
• Determines whether an organism has the ability to reduce nitrate to nitrite
• Detected by the addition of N,N-Dimethyl-αnaphthylamine and sulfanilic acid
Nitrate Reduction Test
33
The nitrate reduction test determines whether an organism has the ability to reduce nitrate to nitrite and reduce nitrite further to nitrogen gas (N2).
Positive reaction – red color (diazo red dye)
34
• Determines the presence of the cytochrome oxidase system that oxidizes reduced cytochrome with molecular oxygen
• Differentiates Enterobacteriaceae (oxidase-negative)
from Pseudomonads (oxidase-positive)
• _______ – tetramethyl-p-phenylenediamine
dihydrochloride
- Oxidase Test
- Reagent
35
Oxidase test is used to identify microorganisms
containing the enzyme cytochrome C oxidase
that is important in the electron transport chain.
Positive reaction – purple or lavender color
36
• Determines whether a microorganism can hydrolyze urea (by the action of urease enzyme), releasing a sufficient amount of ammonia to produce a color change by a pH indicator
• ____________ - Christensen’s Urea Agar
• ____________ – phenol red
- Urease Test
- Preferred medium
- pH indicator
37
• Is used to identify bacteria capable of hydrolyzing urea using the enzyme urease. It is
commonly used to distinguished genus proteus
from other enteric bacteria. Organisms that
produce urease will hydrolyze urea to form
ammonia, then reacts in solution to form
ammonium carbonate
Positive reaction – bright pink color
38
• Bacteria that produce gelatinases that break down gelatin into amino acids.
• Liquefaction of the gelatin is a positive test
Gelatin Hydrolysis Test
39
• Utilizes the sodium thiosulfate sulfur source to form H2S, a colorless gas –H2S combines
with the indicator, ferrous sulfate producing black color (positive reaction)
Hydrogen Sulfide Production (H2S)
40
Media demonstrate the production of
H2S
o Sulfide-indole-motility agar
o Motility-indole-ornithine agar
o Hektoen enteric agar
o Salmonella-Shigella agar
o Triple sugar iron agar
o Kligler Iron agar
o Lysine iron agar.
41
• 0.4% agar
• Single stab in the medium
• ____________ – SIM (Sulfide-Indole-Motility) Agar
• ____________ – movement away the stab line or hazy appearance throughout the medium
- Motility Test
- Routine medium used
- Positive reaction
42
• Decarboxylase and Dihydrolase Test
• Deamine Test – PAD Test (Phenylalanine Deaminase Test)
AMINO ACID UTILIZATION
43
• Many bacteria have the ability to use amino acids as energy and carbon sources.
• Decarboxylase tests determine whether the bacterial species possess enzymes capable of decarboxylating (removing the carboxyl group, COOH) specific amino acids in the test medium
Decarboxylase and Dihydrolase Test
44
_______________ – lysine and ornithine
- Lysine and ornithine are two amino acids
commonly used to test for decarboxylase
activity.
Two amino acids commonly used
45
_______________ – amine or diamine molecules and CO2
- The products of decarboxylation are amine or
diamine molecules and CO2, with resulting
alkalinity
Products of decarboxylation
46
• Positive reaction – _______
• Negative reaction – _______
- purple
- yellow
47
• Determines whether an organism possesses the enzyme that deaminates phenylalanine to phenylpyruvic acid
- Amino acids can be metabolized by the
aminases that remove amine group, nh group,
the surface of the slant is inoculated with a
bacterial colony.
Phenylalanine Deaminase Test (PAD Test)
48
Reagent – _________
- after inoculation addition of 10% ferric chloride reagent results in green color if phenyl pyruvic
acid is present. This test is helpful in initial
differentiation of proteus morganella, providencia organisms which are positive from
the rest of the Enterobacteriaceae
10% ferric chloride
49
Positive reaction – ________
green color
50
_________, _________, and ________________ are phenylalanine deaminase-positive
Proteus, Morganella, and Providencia species
51
• It is used primarily to determine whether the bacteria decarboxylate or deaminate lysine
• Useful for differentiating Salmonella spp.
(lysine-positive) from Citrobacter spp (lysine-negative)
• Also useful in differentiating Proteus,
Morganella, and Providencia spp. from most
other members of Enterobacteriaceae
• _____________
• Contains amino acid lysine, glucose, ferric
ammonium citrate and sodium thiosulfate
- Decarboxylase and Dihydrolase Test - Lysine Iron Agar Slant
- Butt-slant medium
52
• __________ – bromcresol purple
- LIA is inoculated in the same manner as a TSI
agar slant. LIA is most useful in conjunction
with TSI in screening stool specimens for the
presence of enteric patho- gens, differentiating
Salmonella spp. (lysine-positive) from
Citrobacter spp. (lysine-negative).
pH indicator
53
Lysine Decarboxylation (detected in butt):
• Positive Test: Purple slant/purple butt
(alkaline) – K/K
• Negative Test: Purple slant/yellow butt (acid), fermentation of glucose only – K/A or R/A
54
Lysine Deamination (detected on slant):
• Positive Test: Red slant – R/A
• Negative Test: Slant remains purple –K/K or
K/A
• Alkaline – K
• Acid – A
• Red production (Positive for lysine deamination) – R
55
OPPORTUNISTIC MEMBERS OF THE FAMILY
ENTEROBACTERIACEAE
• Escherichia spp.
• Klebsiella spp.
• Enterobacter spp.
• Serratia spp.
• Hafnia spp.
• Proteus spp.
• Morganella spp.
• Providencia spp.
• Edwardsiella sp.
• Citrobacter spp.
56
- Most members of the Enterobacteriaceae are
opportunistic or causes secondary infections
• The most significant species in the genus
Escherichia
ESCHERICHIA COLI (COLON BACILLUS)
57
Cultural Characteristics:
• MAC – lactose-positive (pink) colonies
• EMB – greenish metallic sheen
58
Is associated with the following properties:
• Fermentation of glucose, lactose, trehalose,
and xylose
• Production of indole from tryptophan
• Glucose fermentation by the mixed acid
pathway: methyl red-positive and VogesProskauer-negative
59
• Uropathogenic E. coli
• Enterovirulent E. coli or Diarrheogenic E. coli
- E. coli may cause several different GI syndromes. Based on virulence factors, clinical
manifestation, epidemiology, and different O
and H serotypes, there are five major categories of diarrheogenic E. coli:
ESCHERICHIA COLI – PATHOGENIC STRAINS
60
Categories:
- Enterotoxigenic E. coli (ETEC)
- Enteroinvasive E. coli (EIEC)
- Enteropathogenic E. coli (EPEC)
- Enterohemorrhagic E. coli (EHEC)
- Enteroadherent
- Diffusely adherent E. coli (DAEC)
- Enteroaggregative E. coli (EAEC)
61
• Strain of E. coli that is considered as the most common cause of UTIs in humans
• Pili – primary virulence factor associated with the ability of E. coli to cause UTIs
• Other factors include cytolysins and aerobactins
Uropathogenic E. coli (UPEC)
62
• Associated with diarrhea of adults and especially children in tropical and subtropical climates
- ETEC strains are asso- ciated with diarrhea of
adults and especially children in tropical and
subtropical climates, especially in developing
countries, where it is one of the major causes
of infant bacterial diarrhea.
• It is the most common cause of diarrheal disease
• Also referred to as “____________”
- Enterotoxigenic E. coli
- traveler’s diarrhea
63
_______ – “__________” – deficiency of hydrochloric acid within the stomach
High risk - "Achlorydia"
64
• Causes “____________”
- Severe diarrhea (<1 year old)
• Outbreak occurs in hospital nurseries and daycare centers
• Rarely seen in adults
• Characterized by low-grade fever, malaise, vomiting and diarrhea
• Stool contains large amount of mucus, no blood present
- Enteropathogenic E. coli
- infantile diarrhea
65
• Produce dysentery with direct penetration, invasion, and destruction of the intestinal mucosa
• Very similar to the diarrheal illness produced by Shigella spp.
• Differentiated by motility test and lactose fermentation
• May be nonmotile, NLF
• Characterized by fever, severe abdominal cramps, malaise and watery diarrhea
Enteroinvasive E. coli
66
• O157: H7 strain of E. coli
• Associated with hemorrhagic diarrhea and HUS (hemolytic uremic syndrome)
• HUS – characterized by low platelet count, hemolytic anemia and kidney failure
• Watery diarrhea - Bloody diarrhea with abdominal cramps, low grade fever or an absence of fever
• Stool contains no leukocytes
• Distinguishing characteristic from Shigella spp. and EIEC infections
Enterohemorrhagic E. coli
67
______________ – Stool culture using MAC containing sorbitol (SMAC)
- _____________ – E. coli O157:H7 (colorless)
- _____________ – other E. coli strains (pink colonies)
- Primary screening test
- Non-sorbitol fermenter
- Sorbitol fermenter
68
___________- 4-methylumbelliferyl-β-D-glucuronide (MUG) assay
Additional test
69
Associated with two kinds of human disease: diarrheal syndromes and UTIs
Enteroadherent E. coli
70
Two types: _____________
- _________ – UTIs and diarrheal disease
• Cystitis in children and acute pyelonephritis in pregnant women
• Chronic or recurring UTIs
- ________ – causes diarrhea by adhering to the
surface of the intestinal mucosa
• Produces watery diarrhea, vomiting,
dehydration and occasionally abdominal pain mostly in children
• WBCs and RBCs are absent from the stool
• Cause of diarrhea in HIV positive patients
- DAEC and EADC
- DAEC
- EAEC
71
• One of the most common cause of septicemia and meningitis in neonates
- accounting for about 40% of the cases of gramnegative meningitis. Similar infections resulting fromthis organism are uncommon in older children. A newborn usually acquires the infection in the birth canal just before or during delivery, when the mother’s vagina is heavily colonized. Infection may also result if contamination of the amniotic fluid occurs.
ESCHERICHIA COLI - EXTRAINTESTINAL INFECTIONS
72
OTHER ESCHERICHIA SPECIES
- E. hermannii
- E. vulneris
- E. albertii
73
- Yellow-pigmented organism; isolated from
CSF, wounds and blood
- Foodstuffs such as raw milk and beef
• Reports of isolating E. hermannii from foodstuffs such as raw milk and beef, the same sources as E. coli O157:H7, have been published. However, its clinical significance is not yet established.
E. hermannii
74
- Yellow-pigmented colonies (more than half of
strains); isolated from humans with infected
wounds
• More than half of the strains of E. vulneris
also produce yellow-pigmented colonies.
E. vulneris
75
• Associated with diarrheal disease in children
E. albertii
76
Members of these genera are usually found in the intestinal tract of humans and animals or
free-living in soil, water, and on plants. These
microorganisms have been associated with
various opportunistic and hospital-acquired
infections, particularly pneumonia, wound
infections, and UTIs.
KLEBSIELLA
77
COMMON CHARACTERISTICS
• LF on MAC
• Most grow on SCA and in Potassium Cyanide Broth (KCN)
• H2S negative
• A few hydrolyze urea slowly
• All are MR- and VP+
• With a few , no indole is produced from thryptophan
• Variable motility
78
SPECIES
• K. pneumoniae subsp. pneumoniae
• K. oxytoca,
• K. pneumoniae subsp. ozaenae
• K. pneumoniae subsp. rhinoscleromatis,
• K. ornitholytica,
• K. planticola,
• K. terrigena.
79
• Most commonly isolated specie
- K. pneumoniae is the most commonly isolated
species and has the distinct feature of possessing a large polysaccharide capsule.
• Posses a large polysaccharide capsule
- Responsible for the moist, mucoid colonies
characteristic of K. pneumoniae on MAC
K. pneumoniae (Friedlander’s bacillus)
80
_________________________ – cough up “currant-jelly like” sputum
Causes community – acquired pneumonia
81
• _____________ – polyssacharride capsule
• _____________ – string test
- To differentiate K. pneumoniae to other species and other genus of enterics, string test is done.
- A positive string test is defined as the formation of viscous strings of greater than 5mm in length
when a loop is used to stretch the colony on an
agar plate.
- Neufeld-Quelleng test: Positive
- Growth in potassium cyanide (KCN): positive
- IMViC: - - + +
- TSI: A/A, gas+, H2S-
- K. pneumoniae
- Virulence factor
- Differential test
82
- Produces infections similar to those caused by K. pneumoniae
- Linked to antimicrobial-associated hemorrhagic colitis
- Identical to K. pneumoniae except for its production of indole, and there are reports of ornithine-positive isolates as well
K. oxytoca
83
• Isolated from nasal secretions and cerebral abscesses
• Causes __________ – a tissue-destructive disease restricted to the nose (“foul-smelling” atrophic rhinitis)
- Atrophic rhinitis is a condition that affects the
interior of your nose.
- K. pneumoniae subsp. ozaenae
- atrophic rhinitis
84
• Causes rhinoscleroma – an infection of the nasal cavity that manifests as an intense swelling and malformation of the entire face and neck
K. pneumoniae subsp. rhicoscleromatis
85
• The genus Enterobacter is composed of at least 12 species.
ENTEROBACTER, CRONOBACTER AND PANTOEA
86
Clinically significant species:
- Enterobacter cloacae
- Enterobacter aerogenes
- Enterobacter gergoviae
- Enterobacter hormaechei
87
two most common isolates
E. cloacae and E. aerogenes
88
colony morphology resembles Klebsiella
MAC
89
nationwide outbreak of septicemia resulting from contaminated IV fluids
Pantoea (Enterobacter) agglomerans
90
produces a yellow pigment and has been documented as a pathogen in neonates causing meningitis and bacteremia, often coming from powdered infant formula
Cronobacter (Enterobacter) sakazakii
91
isolated from human sources such as blood, wounds, and sputum.
E. hormaechei
92
is similar biochemically to E. cloacae and has been isolated from blood, urine, feces, sputum, and wounds.
E. asburiae
93
associated with osteomyelitis after traumatic wounds
E. cancerogenus (formerly E. taylorae)
94
- Ornithine decarboxylase (ODC) positive
- Lysine decarboxylase (LDC) is positive by most species (except E. gergoviae and E. cloacae)
- Growth on KCN agar
- Sorbitol fermentation +
- IMVic - - + +
- TSI: A/A (except E. agglomerans K/A), gas+ (except E. agglomerans neg), H2S-
ENTEROBACTER
95
SERRATIA SPECIES:
- S. marcescens (most clinically significant)
- S. liquefaciens,
- S. Rubidaea
- S. Odorifera
- S. Plymuthica
- S. ficaria,
- S. Entomophila
- S. fonticola
96
_____________ – musty and pungent odor or “rotten potato –like” odor
- As the species name implies, it emits a dirty,
musty odor resembling that of rotten potatoes.
S. odorifera
97
ferments arabinose growth in KCN media
S. liquifaciens
98
_____________ – most significant
- S. marcescens is the primary pathogenic
species of the serratia.
- Rare reports on this tribe are diseases resulting from infection with other species of Serratia
- Causes outbreak in nurseries, burn units and
cardiac surgery units
S. marcescens
99
GENERAL CHARACTERISTICS:
- IMViC - - + +
- TSI rxn: K/A, gas +, H2S –
100
• Composed of only one specie: H. alvei
• Gastroenteritis
- _____ has been linked to gastroenteritis and is occasionally isolated from stool cultures.
• Major characteristic: delayed positive citrate reaction
- A delayed positive citrate reaction is a major
characteristic of _______.
HAFNIA
101
• The genus Proteus consists of at least four species. P. mirabilis and P. vulgaris are widely recognized human pathogens.
• They ascend the urinary tract, causing infections in both the lower and the upper urinary tract.
• They can infect the proximal kidney tubules and can cause acute glomerulonephritis, particularly in patients with urinary tract defects or catheterization.
PROTEUS
102
widely recognized human pathogens
P. vulgaris and P. mirabilis
103
most common clinical isolate
P. mirabilis
104
• Only one specie – M. morganii
• Causes UTI and neonatal sepsis
• Motile but does not swarm
• Same biochemical ID as P. vulgaris (except that P. vugaris is citrate +)
• NLF on MAC
• PAD test +
• IMViC + + - -
• LIA rxn: R/A
• TSI rxn: K/A, gas +, H2S –
MORGANELLA
105
is most commonly found in the feces of children with diarrhea
P. alcalifaciens
106
documented pathogen of urinary tract; also diarrheal disease among travelers
P. rettgeri
107
outbreaks in burn units; isolated from urine cuture
P. stuartii
108
formerly identified as a strain of P. alcalifaciens
P. rustigianii
109
The genus Providencia consists of five species: Five species:
- P. alcalifaciens
- P. stuartii
- P. rettgeri
- P. rustigianii
- P. heimbachae
110
Indole
- Proteus penneri
(-)
- Proteus vulgaris
(+)
- Providencia alcalifaciens
(+)
- Providencia stuartii
(+)
- Providencia rettgeri
(+)
- Morganella morganii
(+)
111
Methyl red
- Proteus penneri (+)
- Proteus mirabilis
(+)
- Proteus vulgaris
(+)
- Providencia alcalifaciens
(+)
- Providencia stuartii
(+)
- Providencia rettgeri
(+)
- Morganella morganii
(+)
112
VogesProskauer
- Proteus penneri (-)
- Proteus mirabilis (-) or
(+)
- Proteus vulgaris
(-)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(-)
- Providencia rettgeri
(-)
- Morganella morganii
(-)
113
Simmons citrate
- Proteus penneri (-)
- Proteus mirabilis
(+) or (+)
- Proteus vulgaris
(d)
- Providencia alcalifaciens
(+)
- Providencia stuartii
(+)
- Providencia rettgeri
(+)
- Morganella morganii
(-)
114
Christensen urea
- Proteus penneri (+)
- Proteus mirabilis
(+) or (+)
- Proteus vulgaris
(+)
- Providencia alcalifaciens
(-)
- Providencia stuartii (-)
or (+)
- Providencia rettgeri
(+)
- Morganella morganii
(+)
115
H2S (TSI)
- Proteus penneri (-) (70%)
- Proteus mirabilis
(+)
- Proteus vulgaris
(+)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(-)
- Providencia rettgeri
(-)
- Morganella morganii
(-]
116
Ornithine decarboxylase
- Proteus penneri (-)
- Proteus mirabilis
(+)
- Proteus vulgaris
(-)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(-)
- Providencia rettgeri
(-)
- Morganella morganii
(+)
117
Phenylalanine deaminase
- Proteus penneri (+)
- Proteus mirabilis
(+)
- Proteus vulgaris
(+)
- Providencia alcalifaciens
(+)
- Providencia stuartii
(+)
- Providencia rettgeri
(+)
- Morganella morganii
(+)
118
Acid produced from:
- Proteus penneri
- Proteus mirabilis
- Proteus vulgaris
- Providencia alcalifaciens
- Providencia stuartii
- Providencia rettgeri
- Morganella morganii
119
Sucrose
- Proteus penneri (+)
- Proteus mirabilis
(d)
- Proteus vulgaris
(+)
- Providencia alcalifaciens
(d)
- Providencia stuartii
(d)
- Providencia rettgeri
(d)
- Morganella morganii
(-)
120
Mannitol
- Proteus penneri (-)
- Proteus mirabilis
(-)
- Proteus vulgaris
(-)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(d)
- Providencia rettgeri
(+)
- Morganella morganii
(-)
121
Salicin
- Proteus penneri (-)
- Proteus mirabilis
(-)
- Proteus vulgaris
(d)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(-)
- Providencia rettgeri
(d)
- Morganella morganii
(-)
122
Adonitol
- Proteus penneri (-)
- Proteus mirabilis
(-)
- Proteus vulgaris
(-)
- Providencia alcalifaciens
(+)
- Providencia stuartii
(-)
- Providencia rettgeri
(+)
- Morganella morganii
(-)
123
Rhamnose
- Proteus penneri (-)
- Proteus mirabilis
(-)
- Proteus vulgaris
(-)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(-)
- Providencia rettgeri
(+) or (-)
- Morganella morganii
(-)
124
Maltose
- Proteus penneri (+)
- Proteus mirabilis
(-)
- Proteus vulgaris
(+)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(-)
- Providencia rettgeri (-)
- Morganella morganii
(-)
125
Xylose
- Proteus penneri (+)
- Proteus mirabilis
(+)
- Proteus vulgaris
(+) or (+)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(-)
- Providencia rettgeri
(-) or (+)
- Morganella morganii
(-)
126
Arabitol
- Proteus penneri (-)
- Proteus mirabilis
(-)
- Proteus vulgaris
(-)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(-)
- Providencia rettgeri
(+)
- Morganella morganii
(-)
127
Swarms
- Proteus penneri (+)
- Proteus mirabilis
(+)
- Proteus vulgaris
(+)
- Providencia alcalifaciens
(-)
- Providencia stuartii
(-)
- Providencia rettgeri (-)
- Morganella morganii
(-)
128
The genus ________ and __________ is distinguished from other members of Enterobacteriaceae by the ability to deaminate the amino acid phenylalanine
P.providencia and morganella
129
• NLF in MAC, urease test -
• Positive for lysine decarboxylase (LDC)
• IMViC + + - -
• TSI rxn: K/A, gas +, H2S +
• Members of this genus are negative for urea and positive for lysine decarboxylase, H2S, and indole
• Does not grow on Simmons citrate.
EDWARDSIELLA
130
Three species:
- E. tarda
- E. hoshinae
- E. ictaluri
131
• Consist of 11 species that all have been isolated from clinical specimens
• Most often isolated are C. freundii, C. koseri, and C. braakii
CITROBACTER
132
• Because of the phenotypic characteristic , the genus __________ was formerly in the family Vibrionaceae
• However, phylo genetic studies have shown that ___________ is actually closely related to the members of the family Enterobacteriaceae.
PLESIOMONAS
133
Three major clinical types of gastroenteritis
- The more common watery or secretory
diarrhea
- A subacute or chronic disease that lasts from
14 days to 2 to 3 months
- A more invasive, dysenteric form that resembles colitis
134
The easiest screening procedure is oxidase test performed on colonies from non-selective medias such as SBA or Chocolate agar.
Oxidase positive
135
It is unique because of its positive trio profile of positive ornithine lysine, and arginine
decarboxylase reactions.
Decarboxylase test: positive to trio decarboxylase test
136
PRIMARY INTESTINAL PATHOGENS OF THE FAMILY ENTEROBACTERICEAE
- Salmonella, Shigella and Yersinia
137
• Are groups within a single species of microorganisms which share distinctive surface structures
- Such as bacteria or viruses
-;Type and number of cell-surface antigens
Serotype or Serovar
138
• Members of the genus ________ produce significant infections in humans and in certain animals.
• Many _________ serotypes are typically found in coldblooded animals as well as in rodents and birds (natural host)
• Most pathogenic Enterobacteriaceae
SALMONELLA
139
• ______ – produces clear, colorless, non-lactose
fermenting colonies
• _________ – colonies with black centers are seen due to the production of H2S.
- MAC
- HEA and XLD
140
• NLF
• IMVIC - + - -
• Phenyalanine and Urease Neg
• H2S Producer (except S. paratyphi A)
• Do not grow in KCN medium
Salmonella – Biochemical Features
141
• Previously, the genus Salmonella comprised three biochemically discrete species: S. enteritidis, S. choleraesuis, and S. typhi.
SALMONELLA (cont.)
142
S. enterica – type specie of the genus
- Subspecies:
- S. enterica subsp. enterica (subspecies I)
- S. enterica subsp. salamae (subspecies II)
- S. enterica subsp. arizonae (subspecies IIIa)
- S. enterica subsp. diarizonae (subspecies IIIb)
- S. enterica subsp. houtenae (subspecies IV)
- S. enterica subsp. Indica (subspecies VI)
143
Antigenic Structures
- Somatic O antigen (heat-stable) and flagellar H (heat-labile) antigen – primary; used for serologic grouping of Salmonella
- Capsular K antigen (Vi antigen) – few strains;
prevents phagocytosis
144
Factors responsible for the virulence of
salmonellae have been the subject of
speculation and are still being investigated.
Virulence Factors
145
role in adherence in initiating intestinal infection
Fimbriae
146
causes gastroenteritis
Enterotoxin
147
• Acute gastroenteritis or food poisoning characterized by vomiting and diarrhea
• _________ – most severe form of enteric fever
- Caused by Salmonella serotype Typhi
• _________
- Caused by other Salmonella serotypes (e.g.,
Salmonella Paratyphi and Choleraesuis)
• Nontyphoidal bacteremia
• Carrier state following Salmonella infection
• Humans acquire the infection by ingesting the
organisms in food, water, and milk contaminated with human or animal excreta
- Salmonella – Clinical Infections
- Typhoid fever
- Enteric fevers
148
no known animal reservoirs; infections only occur in humans. Carriers are often the source of infection.
Salmonella serotypes Typhi and Paratyphi
149
• One of the most common forms of “food poisoning”
• Salmonellosis is a common cause of gastrointestinal tract infection.
• Numerous outbreaks have also been linked to calves and poultry at petting zoos.
• GI infection caused by salmonellae results from the ingestion of the organisms through contaminated food
Salmonella – Gastroenteritis
150
poultry, milk, eggs and egg products as well as to handling pets
Source of infection
151
The infective does necessaryto initiate the
disease is one million bacteria. Higher than the
dose required for Shigellosis.
Infective dose - 10⁶ bacteria
152
patients with sickle cell disease and other hemolytic disorders, ulcerative colitis and malignancy
Susceptible to infection
153
____________ of choice include chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole
Antimicrobials
154
• Enteric fever caused by Salmonella Typhi is known as __________
- A febrile disease that results from the ingestion of food contaminated with the organisms
originating from infected individuals or carriers
- Salmonella – Typhoid Fever
155
Clinical features:
- Prolonged fever
- Bacteremia
- Involvement of the reticuloendothelial system,
particularly the liver, spleen, intestines, and
mesentery
- Dissemination to multiple organs
156
caused by Salmonella serotypes Paratyphi A, B, and C and Salmonella serotype Choleraesuis – less severe
Paratyphoid fevers
157
fever accompanied by malaise, anorexia, lethargy, myalgia, and a continuous dull frontal
headache
First week of disease
158
sustained fever with prolonged bacteremia
Second and third week of disease
159
• Bacteremia caused by non-typhoidal salmonella is characterized primarily by prolonged fever and intermittent bacteremia.
• The serotypes most commonly associated with
bacteremia are Typhimurium, Paratyphi, and
Choleraesuis (nontyphoidal Salmonella)
Salmonella – Bacteremia
160
Observed in two different groups:
- Young children, who experience fever and
gastroenteritis with brief episodes of bacteremia
- Adults, who experience transient bacteremia
during episodes of gastroenteritis or develop
symptoms of septicemia without gastroenteritis
161
• Individuals who recover from infection may harbor the organisms in the gallbladder, excreted in feces
• Antimicrobial therapy if gallbladder infection is not evident
• Cholecystectomy has been the only solution to the chronic state of enteric carriers
Salmonella – Carrier State
162
Arabinose Fermentation
- S. serotype Choleraesuis (-)
- S. serotype Paratyphi (+)
- S. serotype Typhi (-)
- Other (+)
163
Citrate utilization
- S. serotype Choleraesuis (V)
- S. serotype Paratyphi (-)
- S. serotype Typhi (-)
- Other (+)
164
Glucose gas production
- S. serotype Choleraesuis (+)
- S. serotype Paratyphi (+)
- S. serotype Typhi (-)
- Other (+)
165
H2S (TSI)
- S. serotype Choleraesuis (V)
- S. serotype Paratyphi (-)
- S. serotype Typhi (+)
- Other (+)
166
Lysine decarboxylase
- S. serotype Choleraesuis (+)
- S. serotype Paratyphi (-)
- S. serotype Typhi (+)
- Other (+)
167
Ornithine decarboxylase
- S. serotype Choleraesuis (+)
- S. serotype Paratyphi (+)
- S. serotype Typhi (-)
- Other (+)
168
Trehalose
- S. serotype Choleraesuis (-)
- S. serotype Paratyphi (+)
- S. serotype Typhi (+)
- Other (+)
169
• Named after the Japanese microbiologist Kiyoshi Shiga who first isolated the organism in 1896
• Closely related with Escherichia
SHIGELLA
170
Species:
- S. dysenteriae,
- S. flexneri,
- S. boydi,
- S. sonnei
171
Characteristics:
• NLF (except S. sonnei)
• Nonmotile
- They lack flagellar antigens
• Produce gas from glucose (except S. flexneri)
• Urease neg
- They do not hydrolyze urea.
• Does not produce H2S
• They do not decarboxylate lysine
• Shigella are fragile (??) organisms
172
Serogroups:
A (S. dysenteriae), B (S. flexneri ), C (S. boydi), D (S. sonnei)
173
Antigenic structure:
Somatic O
174
Specimen:
stool or rectal swab
175
• Humans are the only known reservoir
• Certain groups are affected more than others
• Shigellosis is highly communicable
Shigella – Clinical Infections and Identification
176
causes the enteric disease bacillary dysentery
S. dysenteriae
177
unique in its ability to decarboxylate ornithine
S. sonnei
178
Mode of transmission:
• Direct person-to-person contact
- Via fecal oral route
- Anal-oral sexual activity
- Anal intercourse (men-to-men) – S. flexneri
• Transmitted by flies, fingers and food or water
contaminated by infected persons
179
Mannitol fermentation
- S. dysenteriae (-)
- S. flexneri (+)
- S. boydii (+)
- S. sonnei
(+)
180
ONPG
- S. dysenteriae (V)
- S. flexneri (-)
- S. boydii (V)
- S. sonnei (+)
181
Ornithine decarboxylase
- S. dysenteriae (-)
- S. flexneri (-)
- S. boydii (-)
- S. sonnei (+)
182
Serogroup
- S. dysenteriae (A)
- S. flexneri (B)
- S. boydii (C)
- S. sonnei (D)
183
• The genus _________ currently consists of 14 named species; most are considered environmental species.
• Although many have been isolated from humans, only three species are considered human pathogens.
YERSINIA
184
Three species (human pathogen):
- Y. pestis
- Y. pseudotuberculosis and Y. enterocolitica
- Y. enterocolitica
185
causative agent of plague, a disease primarily of rodents transmitted to humans by fleas
Y. pestis
186
caused sporadic cases of mesenteric lymphadenitis in humans, especially in children,
and generalized septicemic infections in immunocompromised hosts
Y. pseudotuberculosis and Y. enterocolitica
187
___________ – produces an infection that mimics appendicitis
• It has also been found to be the cause
of diarrhea in numerous community
outbreaks.
Y. enterocolitica
188
• The causative agent of the ancient disease plague still exists in areas where reservoir hosts are found. Plague is a disease primarily of rodents.
• It is transmitted to humans by bites of fleas, which are its most common and effective vectors.
• In humans, plague can occur in three forms: the bubonic, or glandular, form; the septicemic form; and the pneumonic form.
Yersinia pestis
189
Three forms of plague in humans:
- Bubonic or glandular form
- Septicemic form
- Pneumonic form
190
most common; results from the bite of an infected flea
Bubonic or glandular form
191
occurs when the bacteria spread to the bloodstream
Septicemic form
192
occurs secondary to bubonic or septicemic plague when organisms proliferate in the bloodstream and respiratory tract
Pneumonic form
193
• Most commonly isolated specie
• Can be acquired from contact with household pets
• Causes enterocolitis or waterborne gastroenteritis
• Associated with the transfusion of contaminated packed red blood cells (sepsis) – survives in cold temperature
Yersinia enterocolitica
194
Related infections
appendicitis-like syndrome, arthritis, and erythema nodosum
195
severe abdominal pain that is concentrated in the right lower quadrant and fever
Appendicitis-like syndrome
196
• common extraintestinal form of Y.enterocolitica infection
• Usually following a GI episode or an appendicitis-like syndrome.
Arthritis
197
inflammatory reaction characterized by tender, red nodules that may be accompanied by itching and burning
Erythema nodosum
198
__________ – cefsulodin, irgasan, novobiocin, bile
salts, and crystal violet
Inhibitory agents
199
• Pathogen of rodents, particularly guinea pigs
• Reservoir are farm and domestic animals , usually birds
• Causes a disease characterized by caseous swellings called _____________ .
Yersinia pseudotuberculosis
200
Indole
- Y. pestis (-)
- Y. enterocolitica (d)
- Y. pseudotuberculosis
(-)
201
Methyl red
- Y. pestis (+)
- Y. enterocolitica (+)
- Y. pseudotuberculosis (+)
202
VogesProskauer
- Y. pestis
- Y. enterocolitica
- Y. pseudotuberculosis
203
25°C
- Y. pestis (-)
- Y. enterocolitica (d)
- Y. pseudotuberculosis (-)
204
37°C
- Y. pestis (-)
- Y. enterocolitica (-)
- Y. pseudotuberculosis (-)
205
Motility
- Y. pestis
- Y. enterocolitica
- Y. pseudotuberculosis
206
25°C
- Y. pestis (-)
- Y. enterocolitica (+)
- Y. pseudotuberculosis (+)
207
37°C
- Y. pestis (-)
- Y. enterocolitica (-)
- Y. pseudotuberculosis (-)
208
Β-Galactosidase
- Y. pestis (+)
- Y. enterocolitica (+)
- Y. pseudotuberculosis (+)
209
Christensen urea
- Y. pestis (-)
- Y. enterocolitica (+)
- Y. pseudotuberculosis (+)
210
Phenylalanine deaminase
- Y. pestis (-)
- Y. enterocolitica (-)
- Y. pseudotuberculosis (-)
211
Ornithine decarboxylase
- Y. pestis (-)
- Y. enterocolitica (+)
- Y. pseudotuberculosis (-)
212
Acid produced from:
- Y. pestis
- Y. enterocolitica
- Y. pseudotuberculosis
213
Sucrose
- Y. pestis (-)
- Y. enterocolitica (+)
- Y. pseudotuberculosis (-)
214
Lactose
- Y. pestis (-)
- Y. enterocolitica (-)
- Y. pseudotuberculosis (-)
215
Rhamnose
- Y. pestis (-)
- Y. enterocolitica (-) or (+)
- Y. pseudotuberculosis (+)
216
Melibiose
- Y. pestis (-)
- Y. enterocolitica (-) or (+)
- Y. pseudotuberculosis (+)
217
Trehalose
- Y. pestis (-)
- Y. enterocolitica (+) or (-)
- Y. pseudotuberculosis (+)
218
Cellobiose
- Y. pestis (-)
- Y. enterocolitica (+)
- Y. pseudotuberculosis (-)
MTAP BACTE
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