Food Borne Illness

Food Borne IllnessFood Borne Illness

Infections that require large infective dosage




Bacteria Salmonella spp. Yersinia enterocolitica and Yersinia pseudotuberculosis Vibrio parahaemolyticus and other vibrios Escherichia coli - Enterotoxigenic (ETEC) Enterohemorrhagic HUS Campylobacter jejuni Listeria

Bacteria Salmonella spp. Yersinia enterocolitica and Yersinia pseudotuberculosis Vibrio parahaemolyticus and other vibrios Escherichia coli - Enterotoxigenic (ETEC) Enterohemorrhagic HUS Campylobacter jejuni Listeria

EnterobacteriaceaeEnterobacteriaceae Classification – more than15 different

genera Classification – more than15 different

generaLactoes Ferm +ve

EscherichiaEnterobacterCitrobacterKlebsiellaPectinobacterium

Lactoes Ferm –ve

ShigellaEdwardsiellaSalmonellaHafniaSerratiaProteusProvidenciaMorganellaYersiniaErwinia

EnterobacteriaceaeEnterobacteriaceae

Morphology and General Characteristics Gram-negative, non-sporing, rod shaped

bacteria Oxidase – Ferment glucose and may or may not

produce gas in the process (aerogenic vs anaerogenic)

Reduce nitrate to nitrite (there are a few exceptions)

Morphology and General Characteristics Gram-negative, non-sporing, rod shaped

bacteria Oxidase – Ferment glucose and may or may not

produce gas in the process (aerogenic vs anaerogenic)

Reduce nitrate to nitrite (there are a few exceptions)


Are facultative anaerobes If motile, motility is by peritrichous flagella Many are normal inhabitants of the

intestinal tract of man and other animals Some are enteric pathogens and others are

urinary or respiratory tract pathogens Differentiation is based on biochemical

reactions and and differences in antigenic structure

Are facultative anaerobes If motile, motility is by peritrichous flagella Many are normal inhabitants of the

intestinal tract of man and other animals Some are enteric pathogens and others are

urinary or respiratory tract pathogens Differentiation is based on biochemical

reactions and and differences in antigenic structure


Most grow well on a variety of lab media including a lot of selective and differential media originally developed for the the selective isolation of enteric pathogens. Most of this media is selective by

incorporation of dyes and bile salts that inhibit G+ organisms and may suppress the growth of nonpathogenic species of Enterobacteriaceae.

Many are differential on the basis of whether or not the organisms ferment lactose and/or produce H2S.

Most grow well on a variety of lab media including a lot of selective and differential media originally developed for the the selective isolation of enteric pathogens. Most of this media is selective by

incorporation of dyes and bile salts that inhibit G+ organisms and may suppress the growth of nonpathogenic species of Enterobacteriaceae.

Many are differential on the basis of whether or not the organisms ferment lactose and/or produce H2S.

Antigenic Structure of Enterobacteriaceae

Antigenic Structure of Enterobacteriaceae

Escherichia coliEscherichia coli

Normal inhabitant of the G.I. tract. Some strains cause various forms of

gastroenteritis. Is a major cause of urinary tract

infection and neonatal meningitis and septicemia.

Normal inhabitant of the G.I. tract. Some strains cause various forms of

gastroenteritis. Is a major cause of urinary tract

infection and neonatal meningitis and septicemia.

E. coliE. coli

May be hemolytic on CBA – more common in pathogenic strains

KEY tests for the normal strain:TSI is A/A + gasLIA K/KUrea – Indole +Citrate –Motility +

There is an inactive biotype that is anaerogenic, lactose – , and nonmotile.

May be hemolytic on CBA – more common in pathogenic strains

KEY tests for the normal strain:TSI is A/A + gasLIA K/KUrea – Indole +Citrate –Motility +

There is an inactive biotype that is anaerogenic, lactose – , and nonmotile.

Escherichia coliEscherichia coli Virulence factors

Toxins

Enterotoxins and Shigella like Toxins

Enterotoxins causes a movement of water and ions from the tissues to the bowel resulting in watery diarrhea.

There are two types of enterotoxin: LT and ST

Virulence factorsToxins

Enterotoxins and Shigella like Toxins

Enterotoxins causes a movement of water and ions from the tissues to the bowel resulting in watery diarrhea.

There are two types of enterotoxin: LT and ST

E. Coli EnterotoxinsE. Coli Enterotoxins LT – is heat labile and LT – is heat labile

and alters the activity of sodium and chloride transporters producing an ion imbalance that results in fluid transport into the bowel.

ST – is heat stable and binds to specific receptors with the same results as with LT.

LT – is heat labile and LT – is heat labile and alters the activity of sodium and chloride transporters producing an ion imbalance that results in fluid transport into the bowel.

ST – is heat stable and binds to specific receptors with the same results as with LT.

Shiga-type toxinsShiga-type toxinsShiga-type toxin – also called the

verotoxin -produced by enterohemorrhagic strains of E. coli (EHEC)

– is cytotoxic, enterotoxic, neurotoxic, and may cause diarrhea and ulceration of the G.I. tract.

Shiga-type toxin – also called the verotoxin -produced by enterohemorrhagic strains of E. coli (EHEC)

– is cytotoxic, enterotoxic, neurotoxic, and may cause diarrhea and ulceration of the G.I. tract.

E. coli infectionsE. coli infections

Gastroenteritis – there are several distinct types of E. coli that are involved in different types of gastroenteritis:

enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC) , enteroaggregative E. coli (EAEC), and enterohemorrhagic E. coli (EHEC).

Gastroenteritis – there are several distinct types of E. coli that are involved in different types of gastroenteritis:

enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC) , enteroaggregative E. coli (EAEC), and enterohemorrhagic E. coli (EHEC).

ShigellaShigella

Shigella Contains four species that differ

antigenically and, to a lesser extent, biochemically.

Shigella Contains four species that differ

antigenically and, to a lesser extent, biochemically.

Shigella speciesShigella species

S. dysenteriae (Group A) S. flexneri (Group B) S. boydii (Group C) S. sonnei (Group D)

Biochemistry TSI K/A with NO gas LIA K/A Urea – Motility - All ferment mannitol except S. dysenteriae S. sonnei may show delayed lactose fermentation

S. dysenteriae (Group A) S. flexneri (Group B) S. boydii (Group C) S. sonnei (Group D)

Biochemistry TSI K/A with NO gas LIA K/A Urea – Motility - All ferment mannitol except S. dysenteriae S. sonnei may show delayed lactose fermentation

Shigella speciesShigella species

Virulence factorsShiga toxin – is produced by S.

dysenteriae and in smaller amounts by S. flexneri and S. sonnei.

Acts to inhibit protein synthesis This plays a role in the ulceration of the intestinal mucosa.

Virulence factorsShiga toxin – is produced by S.

dysenteriae and in smaller amounts by S. flexneri and S. sonnei.

Acts to inhibit protein synthesis This plays a role in the ulceration of the intestinal mucosa.

ShigellaShigella Clinical significance

Causes shigellosis or bacillary dysentery. Transmission is via the fecal-oral route. The infective dose required to cause infection is

very low (10-200 organisms). There is an incubation of 1-7 days followed by

fever, cramping, abdominal pain, and watery diarrhea (due to the toxin)for 1-3 days.

This may be followed by frequent, scant stools with blood, mucous, and pus (due to invasion of intestinal mucosa).

It is rare for the organism to disseminate. The severity of the disease depends upon the

species one is infected with. S. dysenteria is the most pathogenic followed by S.

flexneri, S. sonnei and S. boydii.

Clinical significance Causes shigellosis or bacillary dysentery. Transmission is via the fecal-oral route. The infective dose required to cause infection is

very low (10-200 organisms). There is an incubation of 1-7 days followed by

fever, cramping, abdominal pain, and watery diarrhea (due to the toxin)for 1-3 days.

This may be followed by frequent, scant stools with blood, mucous, and pus (due to invasion of intestinal mucosa).

It is rare for the organism to disseminate. The severity of the disease depends upon the

species one is infected with. S. dysenteria is the most pathogenic followed by S.

flexneri, S. sonnei and S. boydii.

SalmonellaSalmonella

Salmonella Classification has been changing in the

last few years. There is now 1 species: S. enteritica,

and 7 subspecies: 1, 2 ,3a ,3b ,4 ,5, and 6.

Subgroup 1 causes most human infections

2000 sub species

Salmonella Classification has been changing in the

last few years. There is now 1 species: S. enteritica,

and 7 subspecies: 1, 2 ,3a ,3b ,4 ,5, and 6.

Subgroup 1 causes most human infections

2000 sub species

SalmonellaSalmonellaClinically Salmonella isolates are often

still reported out as serogroups or serotypes based on the Kauffman-White scheme of classification.

Based on O and H (flagella) antigensThe H antigens occur in two phases; 1

and 2 and only 1 phase is expressed at a given time.

Polyvalent antisera is used followed by group specific antisera (A, B, C1, C2, D, and E)

Salmonella typhi also has a Vi antigen which is a capsular antigen.

Clinically Salmonella isolates are often still reported out as serogroups or serotypes based on the Kauffman-White scheme of classification.

Based on O and H (flagella) antigensThe H antigens occur in two phases; 1

and 2 and only 1 phase is expressed at a given time.

Polyvalent antisera is used followed by group specific antisera (A, B, C1, C2, D, and E)

Salmonella typhi also has a Vi antigen which is a capsular antigen.


Biochemistry TSI K/A + gas and H2S: S. typhi produces only a small

amount of H2S and no gas , and S. paratyphi A produces no H2S

LIA K/K with H2S with S. paratyphi A giving K/A results Urea – Motility + Citrate +/- Indole -

Virulence factors Endotoxin – may play a role in intracellular survival Capsule (for S. typhi and some strains of S. paratyphi) Adhesions – both fimbrial and non-fimbrial

Biochemistry TSI K/A + gas and H2S: S. typhi produces only a small

amount of H2S and no gas , and S. paratyphi A produces no H2S

LIA K/K with H2S with S. paratyphi A giving K/A results Urea – Motility + Citrate +/- Indole -

Virulence factors Endotoxin – may play a role in intracellular survival Capsule (for S. typhi and some strains of S. paratyphi) Adhesions – both fimbrial and non-fimbrial


Clinical Significance – causes two different kinds of disease: enteric fevers and gastroenteritis. Both types of disease begin in the same

way, but with the gastroenteritis the bacteria remains restricted to the intestine and with the enteric fevers, the organism spreads

Transmission is via a fecal-oral route, i.e., via ingestion of contaminated food or water.

Clinical Significance – causes two different kinds of disease: enteric fevers and gastroenteritis. Both types of disease begin in the same

way, but with the gastroenteritis the bacteria remains restricted to the intestine and with the enteric fevers, the organism spreads

Transmission is via a fecal-oral route, i.e., via ingestion of contaminated food or water.


Proteus, Providencia, and Morganella Are all part of the NF of the GI tract (except

Providencia). All motile, with Proteus swarming PA + Lysine deamination + (LIA R/A) Urea + for most, strongly + for Proteus TSI variable (know the reactions for each in

the lab!) Indole – only P. mirabilis is -

Proteus, Providencia, and Morganella Are all part of the NF of the GI tract (except

Providencia). All motile, with Proteus swarming PA + Lysine deamination + (LIA R/A) Urea + for most, strongly + for Proteus TSI variable (know the reactions for each in

the lab!) Indole – only P. mirabilis is -

Proteus, Providencia, and Morganella

Proteus, Providencia, and Morganella

Virulence factorsUrease – the ammonia produced may

damage the epithelial cells of the UT

Clinical SignificanceUT infections, as well as pneumonia,

septicemia, and wound infections

Virulence factorsUrease – the ammonia produced may

damage the epithelial cells of the UT

Clinical SignificanceUT infections, as well as pneumonia,

septicemia, and wound infections

Enterobacter sakazakii Enterobacter sakazakii Enterobacter sakazakii a Gram-negative rod-shaped pathogenic

bacterium. It is a rare cause of invasive infection with

historically high case fatality rates (40–80%) in infants.

From contaminated infant formulas E. sakazakii as a now classified into a new

genus, Cronobacter, comprising five species

For survivors, severe lasting complications can result including neurological disorders.

Enterobacter sakazakii a Gram-negative rod-shaped pathogenic

bacterium. It is a rare cause of invasive infection with

historically high case fatality rates (40–80%) in infants.

From contaminated infant formulas E. sakazakii as a now classified into a new

genus, Cronobacter, comprising five species

For survivors, severe lasting complications can result including neurological disorders.

Three ways infant formula get contaminated with Cronobacter

sp. ?

Three ways infant formula get contaminated with Cronobacter

sp. ? a) Through the raw material used for producing

the formula; b) through contamination of the formula or

other dry ingredients after pasteurization; and c) through contamination of the formula as it is

being reconstituted by the caregiver just prior to feeding.

Can other foods also be contaminated? Cronobacter sp. has been detected in other

types of food, but only powdered infant formula has been linked to outbreaks of disease.

a) Through the raw material used for producing the formula;

b) through contamination of the formula or other dry ingredients after pasteurization; and

c) through contamination of the formula as it is being reconstituted by the caregiver just prior to feeding.

Can other foods also be contaminated? Cronobacter sp. has been detected in other

types of food, but only powdered infant formula has been linked to outbreaks of disease.

CampylobacterCampylobacter

CampylobacteriosisMost frequent notified enteric

disease

The organism – G-ve, motile, spiral rod

C. jejuni & C. coli Thermophile (25 to 43 deg. C)

CampylobacteriosisMost frequent notified enteric

disease

The organism – G-ve, motile, spiral rod

C. jejuni & C. coli Thermophile (25 to 43 deg. C)


Exponential Slender, curved shaped growth

morphology

Exponential Slender, curved shaped growth

morphology


Characteristics

- thermophile, survives > 1 hour on

hands & moist surfaces - survives refrigeration

- can revert to VBNC

Characteristics

- thermophile, survives > 1 hour on

hands & moist surfaces - survives refrigeration

- can revert to VBNC


The illness

- incubation – 2 to 5 days - febrile prodrome - watery/bloody diarrhoea, abdominal pain & nausea

The illness

- incubation – 2 to 5 days - febrile prodrome - watery/bloody diarrhoea, abdominal pain & nausea

CampylobacterCampylobacter The illness, continued

- infective dose – 1 000 to 10 000 cells - any age group; infants < 1 year &

young adults; males up to 45 years - Rx – fluids, ? erythromycin (resistance)

The illness, continued

- infective dose – 1 000 to 10 000 cells - any age group; infants < 1 year &

young adults; males up to 45 years - Rx – fluids, ? erythromycin (resistance)


Sources

- human – faecal-oral person-to-person

- animal – ruminants, cats, dogs, flies,

birds

Sources

- human – faecal-oral person-to-person

- animal – ruminants, cats, dogs, flies,

birds

Campylobacter jejuniCampylobacter jejuni


Sources - food – raw poultry, raw milk, offal, red

meat

- environment – faeces from infected

animals contaminate soil &

water

Sources - food – raw poultry, raw milk, offal, red

meat

- environment – faeces from infected

animals contaminate soil &

water

Yersinia enterocoliticaYersinia enterocolitica

Yersiniosis

The organism – small G-ve rods of family Enterobacteriaceae

Geographical variation in pathogenic serotypes

Serotype O:3 in NZ

Yersiniosis

The organism – small G-ve rods of family Enterobacteriaceae

Geographical variation in pathogenic serotypes

Serotype O:3 in NZ


Characteristics

- grows at wide range of temperatures

(0 to 44 0 C), aerobically & anaerobically - withstands freezing & survives in damp soil

Characteristics

- grows at wide range of temperatures

(0 to 44 0 C), aerobically & anaerobically - withstands freezing & survives in damp soil


The illness

- incubation – 7 days - abdominal pain (confused with appendicitis) - headache, fever, diarrhoea, nausea & vomiting (children – watery, mucoid

diarrhoea)

The illness

- incubation – 7 days - abdominal pain (confused with appendicitis) - headache, fever, diarrhoea, nausea & vomiting (children – watery, mucoid

diarrhoea)


The illness, continued - infective dose – unknown - children < 4 years & adults 20-34

years - Rx – antibiotics when serious

The illness, continued - infective dose – unknown - children < 4 years & adults 20-34

years - Rx – antibiotics when serious


Sources - human – person-to-person, hospitals

- animal – primary source is pigs (tongue &

tonsils), companion animals, rats & insects

- food – pork & pork products

- environment – drinking & surface water,

sewage sludge

Sources - human – person-to-person, hospitals

- animal – primary source is pigs (tongue &

tonsils), companion animals, rats & insects

- food – pork & pork products

- environment – drinking & surface water,

sewage sludge


Yersiniosis cases in NZ from 1996 to 2004

0

100

200

300

400

500

600

1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

Nu

mb

er

of

ca

se

s

Listeria monocytogenesListeria monocytogenes

Listeriosis(invasive disease & non-

invasive enteritis)

The organism – G+ve ovoid to rod-shaped bacterium

Widespread in environment

Listeriosis(invasive disease & non-

invasive enteritis)

The organism – G+ve ovoid to rod-shaped bacterium

Widespread in environment


Characteristics - grows in wide range of

temperatures (1 to 45o C)

- survives freezing - aerobic & anaerobic conditions

Characteristics - grows in wide range of

temperatures (1 to 45o C)

- survives freezing - aerobic & anaerobic conditions


The illness – invasive form

- incubation – 30 days

- flu’-like symptoms, diarrhoea, vomiting, meningitis,

septicaemia, spontaneous abortion

The illness – invasive form

- incubation – 30 days

- flu’-like symptoms, diarrhoea, vomiting, meningitis,

septicaemia, spontaneous abortion


The illness – invasive form, continued

- infective dose – 100 to 1 000 cells

- pregnant women, newborn babies, the elderly & AIDS patients

- Rx – penicillin, ampicillin +/- gentamicin

The illness – invasive form, continued

- infective dose – 100 to 1 000 cells

- pregnant women, newborn babies, the elderly & AIDS patients

- Rx – penicillin, ampicillin +/- gentamicin


The illness – non-invasive

- incubation – 18 hours - diarrhoea, fever, muscle pain, headache, abdominal cramps & vomiting

The illness – non-invasive

- incubation – 18 hours - diarrhoea, fever, muscle pain, headache, abdominal cramps & vomiting


The illness – non-invasive - infective dose – > 100 thou.

cells/gm - all individuals susceptible - Rx - penicillin, ampicillin +/-

gentamicin

The illness – non-invasive - infective dose – > 100 thou.

cells/gm - all individuals susceptible - Rx - penicillin, ampicillin +/-

gentamicin


Sources - human – person-to-person rare

- animal – diseased animals shed in faeces,

contamination of red meat; silage

- food – ready-to-eat cooked food with long

shelf-life

- raw foods

- environment – widespread in soil, water & sewage

(Hospitals & occupational exposure)

Sources - human – person-to-person rare

- animal – diseased animals shed in faeces,

contamination of red meat; silage

- food – ready-to-eat cooked food with long

shelf-life

- raw foods

- environment – widespread in soil, water & sewage

(Hospitals & occupational exposure)


Listeriosis cases in NZ from 1980 to 2004

0

5

10

15

20

25

30

35

40

19

80

19

82

19

84

19

86

19

88

19

90

19

92

19

94

19

96

19

98

20

00

20

02

20

04

Year

Nu

mb

er

of

ca

se

s

Vibrio, Aeromonas & Plesiomonas

Similarities to Enterobacteriaceae Gram-negativeFacultative anaerobesFermentative bacilli

Differences from EnterobacteriaceaePolar flagella Oxidase positive

Formerly classified together as VibrionaceaePrimarily found in water sourcesCause gastrointestinal diseaseShown not closely related by molecular methods

General Characteristics of Vibrio, Aeromonas and Plesiomonas

Comma-shaped (vibrioid) bacilli V. cholerae, V. parahaemolyticus, V. vulnificus

are most significant human pathogens Broad temperature & pH range for growth on media

18-37C pH 7.0 - 9.0 (useful for enrichment)

Grow on variety of simple media including: MacConkey’s agar TCBS (Thiosulfate Citrate Bile salts Sucrose) agar

V. cholerae grow without salt Most other vibrios are halophilic

Morphology & Physiology of Vibrio

Vibrio spp. (Family Vibrionaceae) Associated with Human Disease

Vibrio spp. (including V. cholerae) grow in estuarine and marine environments worldwide

All Vibrio spp. can survive and replicate in contaminated waters with increased salinity and at temperatures of 10-30oC

Pathogenic Vibrio spp. appear to form symbiotic (?) associations with chitinous shellfish which serve as an important and only recently recognized reservoir

Asymptomatically infected humans also serve as an important reservoir in regions where cholera is endemic

Epidemiology of Vibrio spp.

Taxonomy of Vibrio cholerae >200 serogroups based on somatic O-antigen O1 and O139 serogroups are responsible for

classic epidemic cholera O1 serogroup subdivided into

Two biotypes: El Tor and classical (or cholerae)Three serotypes: ogawa, inaba, hikojima

Some O1 strains do not produce cholera enterotoxin (atypical or nontoxigenic O1 V. cholerae)

Other strains are identical to O1 strains but do not agglutinate in O1 antiserum (non-cholera (NCV) or non-agglutinating(NAG) vibrios) (non-O1 V.cholerae)

Several phage types

Epidemiology of Vibrio cholerae

Cholera recognized for more than two millennia with sporadic disease and epidemics

Endemic in regions of Southern and Southeastern Asia; origin of pandemic cholera outbreaks

Generally in communities with poor sanitation Seven pandemics (possible beginning of 8th)

since 1817 attributable to increased world travel Cholera spread by contaminated water and food Human carriers and environmental reservoirs

Recent Cholera Pandemics7th pandemic: V. cholerae O1 biotype El Tor Began in Asia in 1961 Spread to other continents in 1970s and 1980s Spread to Peru in 1991 and then to most of

South & Central America and to U.S. & Canada By 1995 in the Americas, >106 cases; 104 dead8th pandemic (??) V. cholerae O139 Bengal is first non-O1 strain

capable of causing epidemic cholera Began in India in 1992 and spread to Asia,

Europe and U.S. Disease in humans previously infected with O1

strain, thus no cross-protective immunity

Pathogenesis of V.cholerae Incubation period: 2-3 days High infectious dose: >108 CFU

103 -105 CFU with achlorhydria or hypochlorhydria (lack of or reduced stomach acid)

Abrupt onset of vomiting and life-threatening watery diarrhea (15-20 liters/day)

As more fluid is lost, feces-streaked stool changes to rice-water stools: Colorless Odorless No protein Speckled with mucus

Pathogenesis of V.cholerae (cont.)

Cholera toxin leads to profuse loss of fluids and electrolytes (sodium, potassium, bicarbonate) Hypokalemia (low levels of K in blood) Cardiac arrhythmia and renal failure

Cholera toxin blocks uptake of sodium & chloride from lumen of small intestine

Death attributable to: Hypovolemic shock (due to abnormally low

volume of circulating fluid (plasma) in the body) Metabolic acidosis (pH shifts toward acid side

due to loss of bicarbonate buffering capacity)

Treatment & Prevention of V. cholerae Untreated: 60% fatality Treated: <1% fatality Rehydration & supportive therapy

Oral Sodium chloride (3.5 g/L)+ Potassium chloride (1.5 g/L)+ Rice flour (30-80g/L)+ Trisodium citrate (2.9 g/L)

Intravenous (IV) Doxycycline or tetracycline (Tet resistance may

be developing) of secondary value Water purification, sanitation & sewage

treatment Vaccines

Laboratory Identification of Vibrios

Transport medium - Cary-Blair semi-solid agarEnrichment medium - alkaline peptone broth

• Vibrios survive and replicate at high pH

• Other organisms are killed or do not multiplySelective/differential culture medium - TCBS

agar

• V. cholerae grow as yellow coloniesBiochemical and serological tests

Characteristics and Epidemiology of Aeromonas (Family Aeromonadaceae)

Gram-negative facultatively anaerobic bacillus resembling members of the Enterobacteriaceae

Motile species have single polar flagellum (nonmotile species apparently not associated with human disease)

16 phenospecies: Most significant human pathogens A. hydrophila, A. caviae, A. veronii biovar sobria

Ubiquitous in fresh and brackish water

Acquired by ingestion of or exposure to contaminated water or food

Associated with gastrointestinal disease

Chronic diarrhea in adults

Self-limited acute, severe disease in children resembling shigellosis with blood and leukocytes in the stool

3% carriage rate

Wound infections

Opportunistic systemic disease in immunocompromised

Putative virulence factors include: endotoxin; hemolysins; eneterotoxin; proteases; siderophores; adhesins

Clinical Syndromes of Aeromonas

Afimbriated Aeromonas hydrophila

Nonadherent Afimbriated

Bacterial Cells and Buccal Cells

Adherent Fimbriated

Bacterial Cells and Buccal Cells

Fimbriated Aeromonas hydrophila

Characteristics of Plesiomonas Formerly Plesiomonadaceae Closely related to Proteus & now classified as

Enterobacteriaceae despite differences: Oxidase positive Multiple polar flagella (lophotrichous)

Single species: Plesiomonas shigelloides Isolated from aquatic environment (fresh or

estuarine) Acquired by ingestion of or exposure to

contaminated water or seafood or by exposure to amphibians or reptiles

Self-limited gastroenteritis: secretory, colitis or chronic forms

Variety of uncommon extra-intestinal infections

Epidemiological Features Aeromonas Plesiomonas

Natural HabitatSource of Infection

Fresh or brackish water

Contaminated water or food

Fresh or brackish water Contaminated

water or food

Clinical FeaturesDiarrheaVomiting

Abdominal CrampsFever

Blood/WBCs in Stool

PresentPresentPresentAbsentAbsent

PresentPresentPresentAbsentPresent

Pathogenesis Enterotoxin (??) Invasiveness

Characteristics of Aeromonas and Plesiomonas Gastroenteritis

Date post:	19-Jan-2016
Category:	Documents
Upload:	clea
View:	37 times
Download:	1 times

Food Borne Illness

Documents