PREFINAL PART 1 Flashcards by Jetti .

All species ferment glucose with the production of
acid or acid and gas; can reduce nitrate to nitrito
(EXCEPT

Erwinia and Enterobacter agglomerans

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MOTILE with peritrichous flagella (EXCEPT

Shigella, Klebsiella and Yersinia

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Most of them are present in the intestinal tract as
commensal microbiota, EXCEPT

Plesiomonas, Salmonella, Shigella, Yersinia

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Catalase positive (EXCEPT

Shigella dysenteriae type 1

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Oxidase-negative (EXCEPT

Plesiomonas

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Non encapsulated (except for

Klebsiella and Enterobacter

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Some of them can grow at 1°C to 5°C (Example:

Serratia and Yersinia

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Large, mucoid and gray colonies: colonial
appearance is of little value for initial differentiation
EXCEPT for

Klebsiella and Enterobacter

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Wayson stain can be used to observe the bipolar
bodies of

Yersinia Pestis

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Transport Media of Enterobacteriaceae

Amies, Cary - Blair and Stuart

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Optimal Growth Temperature: 35 to 37 degrees Celsius, EXCEPT for

Serratia and Yersinia and E. coli which can grow at 45°C to 50°С. Salmonella spp. produce colonies

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Large, smooth and gray colonies
Not very significant for initial diagnosis, EXCEPT for Klebsiella and Enterobacter
with MUCOID colonies
Some strains of E. coli are beta hemolytic

BAP

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Used to differentiate E. coli 0157:H7 (sorbitol negative) from other E. coli strains (sorbitol positive)
*pH indicator: Red
*E. coli: clear or colorless
*Others: pink colonies

MAC/Sorbitol Agar

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*Selective media Salmonella/Shigella specially
contaminated samples (stool)
*pH indicator: Phenol Red
for from
*H2S indicator. Sodium Thiosulfate and Ferric Ammonium Sulfate

XLD

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Contains BTB, bile salts, salicin, lactose, and sucrose
*Promotes in the isolation of Salmonella and Shigella
*pH indicator: BTB
*H2S indicator: Ferric Ammonium Citrate

HEA

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Contains eosin Y, methylene blue, Lactose and sucrose
pH indicator: Eosin and Methylene blue

EMB or levine

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Differentiates Salmonella and Shigella from other enteric
Bile salts inhibit gram positive bacteria and other lactose fermenters
Carbohydrate source: Lactose
pH indicator: Neutral red H2S indicator: Sodium Thiosulfate and Ferric Ammonium Sulfate

SSA

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This is a heat stable antigen located on the cell wall.

O antigen, or somatic antigen

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this is a heat labile antigen found on the surface of flagella, structures responsible for motility.

H antigen, or flagellar antigen

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this is a heatlabile polysaccharide found only in certain encapsulated species.

K antigen, or capsular antigen

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Part of the normal GIT microbiota of humans an
animals

Opportunistic Pathogen

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Example of Opportunistic Pathogens

E. coli, Citrobacter, Enterobacter. Klebsiella, Proteus and Serratia

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Not a member of commensal microbiota
Acquired from contaminated food or water
Their presence on given samples are always
significant

True Pathogens

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Example of True Pathogens

Salmonella, Shigella and Yersinia pestis

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- Assess the ability to ferment glucose, lactose, an sucrose and to produce hydrogen sulphide - The ability of a specific bacterium to utilize certain carbohydrates and produce hydrogen sulfide make it an important criterion for bacterial identification

TSI

Composition of TSI

1% lactose, 1% sucrose, 0.1% glucose (10 parts:10parts:1part)

pH indicator of TSI

Phenol red

the ability to deaminate lysine (aerobic process - occurs in slant) or (b) decarboxylase lysine (anaerobic process-occurs In butt)

LIA

Lysine Decarboxylation (detected in butt) -Purple slant/purple butt (alkaline) - K/K

Positive

Lysine Decarboxylation (detected in butt) -Purple slant/yellow butt (acid), fermentation of glucose only K/A or R/A

Negative

Lysine Deamination (detected on slant): - Red slant - R/A

Positive

Lysine Deamination (detected on slant): - Slant remains purple - K/K or K/A

Negative

Isolate is inoculated straight down the center of the semi – solid medium and is tested for the production of hydrogen sulfide, indole, and motility of the organism

SIM

a hazy appearance/cloudiness or growth outside the stab line indicating movement

Motility

Assess the ability of of an organism to decarboxylate/hydrolyze an amino acid to form an amine (putrescine or cadaverine)

Decarboxylase Test (Moeller's Method)

pH indicator of Decarboxylase Test (Moeller's Method)

Bromcresol purple or Phenol red

positive result of Decarboxylase Test (Moeller's Method)

alkaline product (purple or red color)

negative result of Decarboxylase Test (Moeller's Method)

A yellow color indicating glucose fermentation

IDENTIFIES SLOW OR LATE LACTOSE FERMENTERS

ONPG

Positive result of ONPG

Yellow color reaction in 4 hours (disk); 1 hour (broth)

Negative result of ONPG

Colorless

Lactose Fermenter With permease and galactosidase

Enterobacter, E.coli, Klebsiella

Late Lactose Fermenter With galactosidase only

C. freundii Shigella sonnei Serratia

Non Lactose Fermenter No permease or galactosidase

C. koseri Edwardsiella Morganella Proteus Providencia Salmonella Shigella Yersinia

Assess the ability of organisms to produce and maintain stable ACID END PRODUCTS (mixed acid products) like pyruvic acid from glucose fermentation

Methyl Red/Voges Proskauer (MRVP) test

indicator of MRVP

Methyl red

positive result of MRVP

Bright red color at pH4.4 or less

Determines the ability organisms to produce NEUTRAL END PRODUCTS (Acetoin or acetyl methyl red carbinol) from glucose fermentation.

Voges Proskauer

group of species that produce acetoin as the chief end product of glucose metabolism and form smaller quantities of mixed acids

Klebsiella-Enterobacter-Hafnia-Serratia

positive result of voges proskauer

red

Tests for NITRATE REDUCING ORGANISMS (reduce nitrate to nitrite); those nitrate reductase producing

nitrate reduction test

positive result of nitrate reduction test

red

Detects organism capable of deaminating phenylalanine to phenyl pyruvic acid *** Used for the INITIAL DIFFERENTIATION OF PROTEUS, AND PROVIDENCIA the only genera of Enterics

PAD

positive result for PAD

green color slant

Detects urease producing organisms (urea hydrolyzing)

Urea Hydrolysis test

positive result of urea hydrolysis test

From Light orange to magenta slant (Pink)

Rapid Urease (Positive 4 hours)

Proteus, Providencia, Morganella, Helicobacter

Slow Urease (Positive 24 hours)

Klebsiella, Enterobacter, Yersinia, Citrobacter, Serratia

Detects proteolytic enzyme (gelatinases) producing organisms

Gelatin Hydrolysis

positive result of Gelatin Hydrolysis

Partial or total liquefaction

Gelatinase producing

Proteus vulgaris

Non - gelatinase

Enterobacter aerogenes

detects indole - producing organism from tryptophan

Indole test

detects acid producing organisms (as pH indicator)

Methyl red

detects acetoin producing organisms

Voges - Proskauer

detects citrate - utilizing organism as sole source of carbon

Citrate

Detects sodium malonate utilizing organism as sole source of carbon

Malonate Test

Positive result of Malonate Test

Blue color at pH 7.6

A/A Gas (+) H2S (-)

E. coili Klebsiella Enterobacter

K/A Gas (+) H2S (-)

Serratia M. morganii C. koseri

K/A Gas (+) H2S (+)

Salmonella P. mirabilis E. tarda C. freundii

K/A Gas (-) H2S (-)

Shigella Yersinia Plesiomonas Providencia

important opportunistic pathogen with a wide range of associated conditions, including UTI, diarrheal diseases, and central nervous system infections

ESCHERICHIA SPP

IMVC and TSI reaction of Escherichia spp

(+ + --); A/AG; H2S Neg

Colonies exhibit a GREENISH METALLIC SHEEN

EMB

- Most clinically significant species in the Escherichia genus - First described by Escherich in 1885 - MOST COMMON CAUSE OF NOSOCOMIAL URINARY TRACT INFECTION

Escherichia coli (Colon Bacillus)

IMVC and TSI reaction of E.coli

(++ - -); A/AG; H2S Negative

Yellow pigmented organism; isolated from CSF, wounds and blood Source: Food stuffs such as raw milk and beef

E. hermanii

Yellow pigmented organism; isolated from wounds

E. vulneris

Associated with diarrhea in children

E. albertii

MOST COMMON CAUSE OF UTI

UPEC

Most common cause of diarrhea and west "Traveler's Diarrhea"

ETEC

Infantile Diarrhea

EPEC

Dysentery (like Shigella) WATERY DIARRHEA

EIEC

-Hemorrhagic Diarrhea and Colitis - Hemolytic uremic syndrome (HUS) -Bloody diarrhea without WBC - 0157:H7 *Verotoxin 1 & "aka" shiga - like toxin (STX)

EHEC

* Found in the intestinal tract of humans and animals * Associated with various opportunistic and hospital acquired infections, particularly pneumonia, wound infections, and UTIS

Klebsiella spp.

- "aka" FRIEDLANDER'S BACILLUS - Most commonly isolated species with LARGE POLYSACCHARIDE CAPSULE - responsible for its moist mucoid colonies; can be used for presumptive diagnosis - Causative agent of COMMUNITY ACQUIRED PNEUMONIAE; patients cough up a "currant jelly like" sputum

Klebsiella pneumoniae

- POSITIVE STRING TEST - ONPG Positive - Neufeld - Quellung test: Positive - Growth in potassium cyanide (KCN): Positive IMVIC: (-- + +) TSI: A/AG H2S Negative - Phenylalanine deaminase Negative

K. pneumoniae

Infection similar to K. pneumoniae and is linked to antimicrobial-associated hemorrhagic colitis Biochemically, identical to K. pneumoniae EXCEPT FOR ITS PRODUCTION OF INDOLE

K.oxytoca

Isolated from nasal secretions and cerebral abscesses Causes a tissue-destructive disease atrophic rhinitis - restricted to the nose ("foul smelling" atrophic rhinitis)

K. ozaenae

causes rhinoscleroma an infection of the nasal cavity - that manifests as an intense swelling and malformation of the entire face and neck

K. rhinoscleromatis

- Motile Normal flora of the gastrointestinal tract - Opportunistic infections: UTI, RT and wound infections - Growth in MAC resembles that of the Klebsiella spp - Culture: MAC demonstrates pink colonies (Lactose Fermenter - LF) which are sometimes mucoid EMB: FISH EYE COLONIES

Enterobacter spp

Produces YELLOW PIGMENTATION that intensifies 25 degrees Celsius

E. sakazakii

MOST PREDOMINANT ISOLATE of Enterobacter

E. cloacae

Hospital acquired and pathogenic bacterium with broad ability to develop antibiotic resistance

Enterobacter aerogenes

Not usually a primary pathogen but may be associated with UTI and respiratory tract infection

Enterobacter cloacae

Found in respiratory samples and is rarely isolated from blood cultures

Enterobacter gergoviaе

Produces a yellow pigment and has been documented as a pathogen in neonates causing meningitis and bacteremia, often coming from powdered infant formula (CONTAMINATED INFANT MILK)

Cronobacter sakazakii

Osteomyelitis after traumatic wound

Enterobacter cancerogenus

Nationwide outbreak of septicemia resulting from contaminated intravenous fluids E. agglomerans complex, includes members that are lysine-, ornithine-, and arginine negative or "triple decarboxylases-negative

Pantoea

Produces, pink-red pigment "PRODIGIOSIN"

S. marcescens, S. rubidaea and S. plymuthica

Opportunistic pathogens associated with outbreaks in health care settings Late Lactose Fermenter (ONPG Positive) on MAC except for S. fonticola

Serratia spр.

Late Lactose Fermenter (ONPG Positive) on MAC except for

S. fonticola

musty and pungent odor or "rotten potato –like" odor

S. odorifera

IMVC and TSI reaction of Serratia

(-- ++) K/AG, H2S Negative

- most significant pathogenic species of the serratia - Agent of Red Milk

Serratia marcescens

Only one species of Hafnia

H. alvei

Chief reservoirs are reptiles & freshwater fish. Infections often involve aquatic environments. Positive indole reaction differentiates it from Salmonella.

Edwardsiella spp.

- THE ONLY SPECIES RECOGNIZED AS A HUMAN PATHOGEN - Causes BACTEREMIA AND WOUND INFECTIONS - Suspected for some diarrheal cases

E. tarda

Isolated from snakes, birds, and water

E. hoshinae

Enteric septicemia in fish

E. ictaluri

IMVC and TSI of Edwardsiella

(++--) K/AG H2S +

Considered as inhabitants of the GI tract and are associated with hospital-acquired infections (UTIS. pneumonias and intra-abdominal abscesses)

Citrobacter spp.

COLONIES RESEMBLES OF CITROBACTER

E.coli

BIOCHEMICAL REACTION RESEMBLES OF CITROBACTER

Salmonella

- Former member of Vibrio spp. - Only one species under this genus P. shigelloides - Found in soil and aquatic environments (fresh and estuarine waters of tropical and subtropical climates) - Widely-distributed among warm and cold-blooded animals

Plesiomonas spp.

- NOT part of the indigenous normal flora - Associated with enteric diseases and possible extraintestinal infection - Most common MOT: ingestion of - contaminated water or food (uncooked or undercooked seafood such as oysters, clams, or shrimp)

P. shigelloides

IMVC and TSI

(+ +--) K/A, Negative Gas and H2S

- Associated with ascending UTI (UTI affecting both the lower and upper urinary tract) and wound infection - They can infect the proximal kidney tubules and can cause acute glomerulonephritis, particular in patients with urinary tract defects or catheterization

Proteus spp

- easily identified of their SWARMING COLONY on nonselective media like S SBA/BAР

P. mirabilis and P. vulgaris

differentiated from P. vulgaris by the indole and ornithine decarboxylase tests.

P. mirabilis

Indole neg: Ornithine pos

P. mirabilis

Indole pos; Ornithine neg

P. vulgaris

TSI of Proteus

A/AG

- Most commonly associated with urinary tract infections and the feces of children with diarrhea - May be linked with nosocomial outbreaks

Providencia spp

Most commonly found in the feces of children with diarrhea

P. alcalifaciens

Outbreaks in burn units; isolated from urine culture

P. stuartii

Pathogen of urinary tract; also, diarrheal disease among travelers

P. rettgeri

Formerly identified as a strain of P. alcalifaciens

P. rustigianii

Not yet isolated in clinical specimen

P. heimbachae

IMVC and TSI of Providencia

(+ + - +) K/A H2S Negative

- Causes UTI and neonatal sepsis - MOTILE but does not swarm

Morganella spp

IMVC and TSI of Morganella

(++--) K/AG, H2S Negative

The MOST PATHOGENIC enteric causing ENTERIC FEVER (TYPHOID FEVER) and ACUTE GASTROENTERITIS (FOOD POISONING) to humans

Salmonella spp.

All species are motile, EXCEPT for (Salmonella)

Salmonella serotype Pullorum and Salmonella serotype Gallinarum

ll species produce Gas, EXCEPT for (Salmonella)

Salmonella serotype Typhi and Salmonella serotype Gallinarum

Specimen of choice of Salmonella

Blood Stool Urine

All are H2S producer, EXCEPT (Salmonella)

salmonella serotype Paratyphi A

- MOST COMMON FORM OF FOOD POISONING - Source of Infection: Poultry products, milk and handling pets - Infective dose: 106 bacteria

Gastroenteritis FOOD POISONING (8-36 hours)

- FEBRILE DISEASES - DISTINCT FEATURE IS THE PRESENCE OF ROSE SPOTS DURING SECOND WEEK OF FEVER - "Rose spots" colored papules around the umbilical region)

Enteric fever (Typhoid fever) 9-14 days

Occurs with and without extraintestinal infection usually associated with nontyphoidal Salmonella species

Bacteremia

the cook who spread the typhoid during the 1900 affecting 51 individuals. She was an asymptomatic carrier of Salmonella typhi MArry

Mary Mallon (Typhoid Mary)

detects antibodies against somatic (O) and flagellar (H) antigens * Serotypes of Salmonella can be classified through

Widal test Kauffman White Scheme

- So named after the Japanese microbiologist Kiyoshi Shiga who first isolated the organism in 1896 - CLOSELY RELATED WITH ESCHERICHIA (DUE SIMILARITIES IN MOLECULAR ANALYSIS)

Shigella spp

MOST VIRULENT specie of Shigella

S. dysenteriae

ONE OF THE CAUSES OF GAY BOWEL SYNDROME

S. flexneri

All species DO NOT PRODUCE GAS from glucose, EXCEPT (shigella)

S. flexneri

All species are Mannitol fermenters, EXCEPT (shigella)

S. dysenteriae

All species DO NOT DECARBOXYLASE ORNITHINE, EXCEPT (shigella)

S. sonnei

considered late lactose fermenter and has a POSITIVE REACTION WITH THE ONPG

S. sonnei

The MOST VIRULENT species of Shigella that causes

S. dysenteriae

virulence factor of s. dysenteriae

Shiga Toxin

IMVC and TSI of S.dysenteriae

(v+--) K/A, Gas (-) H2s (-)

- Infection is generally self - limiting that demonstrates fever, watery diarrhea (stool without blood) - Most predominant isolate in US - Can decarboxylate ornithine - Only has a single serotype - Produces a "DELAYED" POSITIVE FERMENTATION OF LACTOSE with the formation of pink colonies on MAC agar only after 48 hours of incubation

S. sonnei

- This genus consists of several Yersinia species; most are considered environmental species. - Found in water, soil, and lower animals - Although many have been isolated from humans, only three species are considered human pathogens.

Yersinia spp

Causative agent of plague, a disease primarily of rodents transmitted to humans by fleas

Y. pestis

- The CAUSATIVE AGENT OF BUBONIC PLAGUE - Also known as "PLAGUE BACILLUS" - Primarily a disease of rodents - Class A agent of Bioterrorism Not part of the normal flora of human

Yersinia pestis

Broth - Colonies demonstrate a "STALACTITE -SHAPED" PATTERN - may be isolated on routine culture medium - NLF in MAC, pinpoint at 24hrs in BAP

y. pestis

IMVC and TSI of Y. pestis

(- + --) K/A No Gas, No H2S

- A disease transmitted through flea bites - Can also be transmitted through inhalation of contaminated air droplets and ingestion of anima tissues

Plague

results from the bite of an infected flea (MOST COMMON);

Bubonic plague/glandular

acquired through direct contact with infected individuals; secondary to bubonic plague or primary if inhaled (100% fatality rate if untreated)

Pneumonic/Pulmonary plague

(anthrax)

Bacillus anthracis

(Botulism)

Clostridium botulinum

(Plague)

Yersinia pestis

(Small pox)

Variola major

(Tularemia)

Francisella tularensis

EBOLA, MARBURG)

Filoviruses

Lassa and Machupo

Arenaviruses

results once infection is spread in the blood stream

Septicemic

- MOST COMMONLY ISOLATED SPECIES OF YERSINIA - The causative agent of enterocolitis or WATERBORNE GASTROENTERITIS – self-limiting infection where stools contain blood

Y. enterocolitica

Selective medium of Y. enterocolitica

CEFSULODIN – IRGASAN 、- NOVOBIOCIN (CIN) demonstrates BULL'S EYE appearance or dark red or burgundy

IMVC and TSI of Y. enterocolitica

(v +--) K/A No Gas, No H2S

- Pathogen of animals particularly rodents and guinea pigs - Farm/domestic animals and birds serve as reservoir host: turkeys, geese, pigeons, doves, and canarie - Causes a disease characterized by caseoUS swellings called pseudotubercles - The disease is often fatal in animals - (CAUSES ACUTE MESENTERIC LYMPHADENITIS)

Y. pseudotuberculosis

Usually found in water; however, they occasionally occur in clinical specimens

Budivicia

Biochemically similar to Citrobacter and Kluyvera species,

Buttiauxella

Recovered from sputum, blood, and wounds; C. davisae (most common)

Cedecea

From human blood cultures or respiratory specimens; demonstrates resistance to multiple antimicrobial agents

Ewingella

Found in respiratory, urine, and blood cultures. Most strains are nonpigmented, but occasional isolates may produce a reddish blue or violet pigment. All species resemble E. coli colonies growing on MAC agar

Kluyvera

Isolated from septicemia and wounds culture; IMVIC reactions similar to E. coli; negative for lysine and ornithine decarboxylase and arginine dihydrolase

Leclercia

Relatively inactive; isolated from patients with hospital-acquired infections. H2S producer; shows weak reactions with Salmonella antisera

Leminorella

Contains one species, M. wisconsensis

Moellerella

natural habitat is the lumen of entomopathogenic nematodes, but strains have occasionally been isolated from human specimens

Photorhabdus

Psychrotolerant, growing at 4° C; no single characteristic that distinguishes them from the other members of the Enterobacteriaceae

Rahnella

Tatumella ptyseos is the only species of the genus Tatumella; Isolated from human sources, especially sputum, and may be a rare cause of infection

Tatumella

is the only species in this genus known to be associated with humans, and although it is very rarely isolated, it is biochemically similar to Salmonella.

Trabulsiella

Biochemically similar to Hafnia but differ primarily by yielding negative Voges-Proskauer test results; isolated from human specimens,

Yokenella

PREFINAL PART 1 Flashcards

(187 cards)