Normal bacterium Flora of the Gastrointestinal tract

Enterobacteriaceae

Dr. Berek ZsuzsaDr. Berek Zsuzsa08 November 201108 November 2011

Normal bacterium Flora of the Gastrointestinal tract

GRAM NEGATIVE RODS

AEROBBordetellaBrucellaFrancisella

PseudomonasAcinetobacterLegionella

FACULTATIVE ANAEROBHaemophilusPasteurella

Familia:EnterobacteriaceaeVibrionaceae

CardiobacteriumEikenellaKingellaActinobacillus

ANAEROBBacteroidesPrevotellaPorphyromonasFusobacterium

MICROAEROPHILCampylobacterHelicobacter

Normal bacteriumFlora of the

Gastrointestinal tract

Normal bacterium flora of theGastrointestinal tract

• Significance:experiments with germ-free animals

•• StomachStomach (103–106 cfu/g)– Low pH– Resident micro flora Ø– Transient flora +– Hypochlorhydria, stasis ⇒

Lactobacillus (Boas-Oppler) & Sarcinaspp.

•• Small intestineSmall intestine (105–107 cfu/g)– Digestive enzymes & bile, rapid peristaltic– Resident micro flora Ø– Transient flora +

•• Large intestineLarge intestine (109–1011 cfu/g)– Abundant resident micro flora

Anaerobes90–95% of the species∼ 1011 cfu/g faecesResident

Bifidobacterium bifidumBacteroides fragilisEubacterium spp.Clostridium spp.

TransientAnaerobe KokkenFusobakterienLactobacillen

Facultative anaerobes5–10% of the species∼ 103–109 cfu/g faecesResident

Escherichia coliEnterococcus spp.

TransientKlebsiella spp.Enterobacter spp.Proteus spp.Providencia spp.Pseudomonas spp.Bacillus spp.yeasts, Protozoa

Normal bacterium Flora of the colon inadults (>400 Species)

• Breast feeding– Resident

• Bifidobacteria (pH 5,5)– Colonisation of other species is

inhibited (vitamin K substitution!)

• Composite feeding– Primarily

• Facultative anaerobes– Later

• Bacteroides fragilis

Normal bacterium flora of thecolon in children

Scanning electron micrograph of the colon mucosa of rat

⎢: bacterium layer, L: lumen, B: bacteria, T: intestinal tissue

Magnification: 262× Magnification: 2.624×

Significance of the normal bacterial flora of the colon

• Decomposition of some nutrients, enterohepaticrecirculation of bile

• Production of vitamins: vitamin K & B-complex• Production of gases ⇒ distension ⇒ normal

peristaltic• Constant physical & chemical stimuli ⇒ constant

mucosal turnover• Biofilm formation, blocking epithelial receptors,

competition for nutrients, bacteriostatic products ⇒inhibition of the colonisation of pathogenic bacteria

• Constant antigen stimulus ⇒ extrauterindevelopment and functioning of the immune system

Role of normal bacterial flora of the colon in pathological processes

•• Extra intestinal infectionsExtra intestinal infections

•• TranslocationTranslocationImmune Immune

compromised patientscompromised patientsObstructionsObstructionsShockShock

ConsequencesConsequencesEndotoxaemiaBacteriaemiaSepsis

Bacterial translocation in rat after experimental intestinal obstruction

AA BB

A: A: lifting of the epithelial cells from the lifting of the epithelial cells from the

lamina lamina propriapropria & bacterial invasion& bacterial invasion

B: B: coccicocci and rods inand rods in

the the submucosalsubmucosal lymphatic vesselslymphatic vessels

Alteration of the balance of the normal bacterial flora of the colon

•• CausesCauses– Malnutrition– Broad spectrum per os antibacterial therapy

•• ConsequencesConsequences– Maldigestion & maladsorption, vitamin deficiency– Alteration of the normal peristaltic, increased

gastrointestinal gas formation•• Antibiotic associated diarrhoeaAntibiotic associated diarrhoea

– Mild: „common” diarrhoea– Severe: pseudomembranous colitis

(Clostridium difficile)

PseudomembranousPseudomembranous colitiscolitis

Thickened wall of the colon Thickened wall of the colon transversumtransversum

Characteristic yellow plaquesCharacteristic yellow plaquesC. difficileC. difficile & & neutrophilsneutrophils

Gram negative facultativeanaerobic rods

Enterobacteriaceae I.

Enterobacteriaceae

Morphology: - Gram negative rods- pili (ex.: Klebsiella, Shigella)

Cultivation:easy, simple (Agar, Blood-agar) MediaDifferentiation: pathogenic-facultative pathogenic(Biochemical reactions)

a) Selective-Mediab) Differential-Mediac) Indicator-Media

Antigens and Virulence factors:O (cell-wall)H (Flagella)K (capsule)surface ProteinsPiliExotoxinsEndotoxin

Enterobacteriaceae

Enterobacteriaceae

Facultative pathogensgenusEscherichia

Klebsiella GroupEnterobacterEdwardsiellaCitrobacter

Proteus GroupSerratiaProvidenciaMorganella

Obligate pathogens (genera)E. Coli

ETEC (enterotoxic)EPEC (enteropathogen)EIEC (enteroinvasive)EHEC (enterohemorrhagic)EAggEC (enteroaggregativ)

ShigellaS. dysenteriaeS. flexneriS. boydiiS. sonnei

SalmonellaS. typhiS. paratyphi

YersiniaY. pestisY. pseudotuberculosisY. enterocolitica

Enterobacteriaceae - Facultative PathogensKlebsiella, Proteus, Escherichia etc. Extraintestinal clinical findings – ALL purulent infections:

a) urinary tract infectionsb) cholecystitis, cholangitisc) peritonitis (local, diffuse)d) pneumoniae) meningitisf) wound infectionsg) sepsish) iatrogen/nosokomial infections

Diagnosis: isolation, identificationTreatment: antibiogram (ESBL)

Serratia marcescens - Serratia marcescens Durch Prodigiosin rotgefärbte Kolonien von Serratia marcescens auf Agargel.

www.biologie.de

pathmicro.med.sc.edu

TSI Medium Identification

Top row, Proteus vulgaris; second row, unidentified enteric bacterium; thirdrow, Klebsiella pneumoniae; bottom row, Vibrio alginolyticus.

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E. coli with Fimbriae

Urinary tract infections (UTI)Urinary tract infections (UTI)

www.spiceisle.com

•• E. coli E. coli (80%)(80%)– Predisposition– Ascending

(rarely haematogenic)– Cystitis, pyelonephritis– Virulence factors (UPEC-strains)

• Haemaggl. adhesion fimbriae– Mannose resistant (MR) fimbriae

(F-antigen), P-fimbriae (blood group P substance) ⇒pyelonephritis

– Mannose sensitive (MS) fimbriae ⇒cystitis

• Haemolysines

• P. mirabilis, P. vulgaris– Predisposition– Ascending infection– Nosocomial

(catheter, operation)– Virulence factors

• Flagellae: motility

• Adhesion fimbriae• Urease

(pH↑, irritation, urinary stones)

P. mirabilis: Swarming

www.sciencebuddies.org

Urinary tract infections (UTI)Urinary tract infections (UTI)

P. mirabilis

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P. mirabilis

Swarming- On cells

www.nrc-cnrc.gc.ca

biology.clc.uc.edu

Proteus vulgaris flagellar - staining

A: Proteus, Providentia – B: Urease Test - / +

helios.bto.ed.ac.uk

Neonatal Meningitis & Sepsis

•• E. coliE. coli K1K1(80–85%)

• K1-antigen – Identical with

Meningococcus B-ag– Tolerance ⇒

no antibody response– Translocation

Pneumonia

• Nosokomial• Predisposition• Pathogens

E. coli,K. pneumoniae,K. oxytoca, Enterobacter spp. Bronchopneumonia Lobar pneumonia

(Friedländer)K. pneumoniae

Klebsiella pneumoniae – Friedländer Pneumonia

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www.icbm.de

Klebsiella pneumoniae

mucoid colonies – capsule

www.lf3.cuni.cz


Enterobacter cloacae Klebsiella pneumoniaeMucoid colonies

Intra-abdominal Infections

Diffuse peritonitis after perforation of the colon

Free abdominal air below the diaphragm: perforation

Enterobacteriaceae

Facultative pathogensgenusEscherichia

Klebsiella GroupEnterobacterEdwardsiellaCitrobacter

Proteus GroupSerratiaProvidentiaMorganella

Obligate pathogens (genera)Escherichia coli (species)

ETEC (enterotoxic)EPEC (enteropathogen)EIEC (enteroinvasive)EHEC (enterohemorrhagic)EAggEC (enteroaggregativ)




FIGURE 25-1 Virulence mechanisms of E coli.

Medmicro

EIEC

ETEC

EAggEC

FIGURE 25-2 Pathogenesis of E. coli diarrhoeal disease.

Medmicro

Pathogenic E. coli strains-1

ETEC (enterotoxic)LT (heat-labile) ST (heat-stable)

ST mode of action (hyperactivation): ADP-Rybosilation GuanilcyclasecGMP water and electrolyte loss

Fimbriae (CFA = colonisation factor antigens)

FIGURE 25-3 Cellular pathogenesis of E coli having CFA pili.

Medmicro

ETEC

Fig.4.26 Enterotoxigenic E. coli infection. Transmission electron micrograph showing bacteria adhering to the brush-border of human intestinal mucosal cells. By courtesy of Dr. S. Knutton

ETEC

FIGURE 25-4 Laboratory methods for isolation and identification of ETEC.

Medmicro

Fig. 4.14 Bacterial diarrhea. Y1 adrenal cell assay for E. coli LT enterotoxin, showing normal cells (left) and cells after exposure to LT toxin (right). Note disruption of monolayer and rounding up cells. By courtesy of Dr. H.L. DuPont.

ETEC

Pathogenic E. coli strains-2-3EPEC (enteropathogenic) O26; O55; O111; O126…

Adhaesion: Adherence Factor (EAF)Bundle Forming Pilus (BFP)Type III. Secretion-system*: Protein filaments (EspA)Tir (translocated intimin receptor)Intimin (eae*) Actin; brush-border lost cell death* Chromosome coded

EAggEC (enteroaggregativ)Fimbriae, ST-like, Haemolysin-like Toxin

Fig.4.19 E. coli diarrhea. Electron micrograph of enteropathogenicE. coli (arrowed) attached to mucosal epithelial cells of ileum. The microvillus border of the epithelial cells has been largely destroyed by bacteria and the cells show signs of degeneration. X3000 By courtesy of Dr. J.R. Cantey

EPEC

Fig.4.27 Enteropathogenic E. coli infection. Electron micrograph showing close, localized adherence of bacteria to human intestinal mucosal cells and localized destruction of microvilli. By courtesy of Dr. S. Knutton

EPEC

Fig. 4.28 Enteropathogenic E. coli infection. Fluorescent actin test specific for EPEC organisms. Left: fluorescent microscopy showing aggregated actin. Right: phase contrast microscopy showing location of bacteria. By courtesy of dr. S. Knutton

EPEC


EIEC (enteroinvasive)

O28; O32; O112; O115; O124, O136; O143, O144 u.a.

Pathogenesis:s. Shigella ProteinsType III. Secretion-system

FIGURE 25-5 Cellular pathogenesis of invasive E coli

EIEC

Fig. 4.17 Enteroinvasive E. coli infection. Invasion of mucosal layer of the intestine by E. coli organisms. There is necrosis of the mucosal layer at the site of invasion (left). Transmission electron micrograph showing enteroinvasive E. coli organisms within HEp-2 cell (right). By courtesy of Dr. S. Knutton.

EIEC

Fig. 4.31 Enteroinvasive E. coli infection. EIEC organisms invading HeLa cells in vitro. By courtesy of Dr. S. Knutton.

EIEC


EHEC (enterohemorrhagic) = VTEC O157:H7

SLT = Verotoxin = Shiga Toxin (stx1, 2, 2c) Mode of action: Protein synthesis inhibitor cytotoxic Haemolysin

Clinical finding, disease:HUS (haemolytic uraemic syndrome)

Haemolytic AnaemiaTrombocytopeniaacute kidney failure

Haemorrhagic colitis

Pathogene E. coli strains

Transmission electronmicrograph of Escherichia coli O157:H7


EHEC(enterohaemorrhagic)= VTEC O157:H7

EHEC (enterohemorrhagisch) = VTEC O157:H7

Fig. 4.29 Enterohaemorrhagic E. coli infection. Assay for Shiga-like toxin (Verotoxin) produced by EHEC (Serotype O157). Left: Normal monolayer of Vero cells. Right: Destruction of Vero cells by the toxin. By courtesy of Dr. S. Knutton

Fig. 4.30 Enterohaemorrhagic E. coli infection. Weigert stain showing fibrin ‘thrombi’ in glomerular capillaries in haemolytic uraemic syndrome. By courtesy of Dr. H.R. Powell

Pathogen E. coli strains

DiagnosisDirect detectionSerotyping

ProphylaxisExpositions prophylaxis

TherapyWater and electrolyte substitutionAntibiogram


Enterobacteriaceae II.

GRAM NEGATIVE RODS



FACULTATIV ANAEROBHaemophilusPasteurella





Enterobacteriaceae

Morphology: - Gram negative rods- pili(ex.: Klebsiella, Shigella)

Cultivation:easy, simple (Agar, Bloodagar) MediaDifferentiation: pathogenic-facultative pathogenic(Biochemical reactions)

a) Selectiv-Mediab) Differential-Mediac) Indicator-Media

Antigens and Virulence factors:O (cell-wall)H (Flagella)K (capsule)surface ProteinsPiliExotoxinsEndotoxin

Enterobacteriaceae

BACTERIAL GI TRACT INFECTIONSI. Type EnterotoxinHypersecretionSmall intestine

watery diarrhea

Vibrio choleraeEscherichia coli(ETEC)

II. TypeInflammationInvasion in MucosaLarge intestine

pus, blood, mucus in stool

ShigellaE. coli (EIEC) (EPEC, EHEC)SalmonellaYersinia enterocoliticaCampylobacter jejuniAeromonas sp.Vibrio parahaemolyticus

Clostridium difficileClostridium perfringens

III. TypePenetration,GeneralisationBacterium intracellularIleum

Typhus, Sepsis

Salmonella typhiS. paratyphi A, BYersinia enterocoliticaY. pseudotuberculosisCampylobacter fetus

Exogen, peroral Infection, faecal–oral transmission route

Enterobacteriaceae

Facultative pathogenesgenusEscherichia

Klebsiella GruppeEnterobacterEdwardsiellaCitrobacter

Proteus GruppeSerratiaProvidenciaMorganella

Obligate pathogens (genera)Escherichia coli

ETEC (enterotoxic)EPEC (enteropathogenic)EIEC (enteroinvasive)EHEC (enterohemorrhagic)EAggEC (enteroaggregativ)




Salmonellae

www.ltsa.frwww.about-salmonella.com

Salmonella sp.

Salmonella typhi, S. paratyphi A, B, C

Antigen structure of Salmonella typhigripsdb.dimdi.de

Obligate human pathogens

AntigensOH (flagella)superficial Vi Ag = capsule


PathogenesisSource of infectionsick, carriers; Contaminated food, drinking waterPortal of entrymouth gut blood Organs: spleen, liver, bile, bone-marrrow, kidneys, brainIleum: ulceration (bleeding, Perforation)

Clinical findings:Typhus abdominalisParatyphus

Please, learn the latin terms!The english enteric fever or typhoidfever does not tell, which bacteriumcaused the disease!


Figure 2. Flagellar stain of a Salmonellatyphi. Like E. coli, Salmonella are motile by means of peritrichous flagella. A close relative that causes enteric infections is the bacterium Shigella. Shigella is not motile, and therefore it can be differentiated from Salmonella on the basis of a motility test or a flagellar stain. (CDC)

Figure 1. Salmonella typhi, the agent of typhoid. Gram stain. (CDC)

www.textbookofbacteriology.net

Typhus abdominalis

Roseolenartiges, makulopapulöses Exanthem bei Typhus abdominalis gripsdb.dimdi.de

www.wrongdiagnosis.comRose spots on abdomen of a patient with typhoid fever due to the bacterium Salmonella typhi.

Rose spots on the chest of a patient with typhoid fever due to the bacterium Salmonella typhi. www.wrongdiagnosis.com

Fig. 4.37 Typhoid fever. Numerous ulcers of the small intestine overlying hyperplastic lymphoid follicles (Peyer’s patches). By courtesy of Dr. J. Newman.

Fig. 4.39 Typhoid fever. Mononuclear cells and red blood cells in the stool. Trichrome stain. By courtesy of Dr. H.L. DuPont.

Typhus abdominalisDiagnosisDirect detection (blood, stool, Urine)Selective mediaAntibody detection

(tube-Agglutination)

ProphylaxisExpositions prophylaxisImmune prophylaxis:1) Active oral immunisation with

Ty21, an apathogenic, attenuated strain

2) Parenteral injection with Vi capsule polysaccharideS. typhi-strain Type-2

TherapyAmpicillinTrimethoprimChloramphenicol

Carriers!!

„Typhoid Mary”

www.spiceisle.com

Salmonella - SalmonellosisUbiquitous: S. typhimurium, S. enteritidis etc.

Pathogen for birds, eggs, swine, cattle, mouse, rat and human

PathogenesisSource of infection: from infected animals, contaminated foodBacteria multiply in the food! Endotoxin free

Clinical finding:FOOD POISONING – Endotoxin effectNo bacterium multiplication in guts, self limited(Gastro)enteritis – bacteria can multiply in guts, type II. diarrhoea, not always self limited

Diagnosis: direct detection (stool, food)Prophylaxis: food and kitchen hygiene

Figure 21-3 Invasion of intestinal mucosa by Salmonella.

medmicrotyphus

www.idph.state.il.us

spacescience.comSalmonella sp.

www.arches.uga.eduSalmonella sp.

http://www.cvm.uiuc.edu/courses/VP341/NFFI/sld008.htm

www2.nphs.wales.nhs.uk

Salmonella enterica


Figure 3. Salmonella sp. after 24 hours growth on XLD agar.



Figure 4. Colonial growth Salmonella choleraesuissubsp. arizonae bacteria grown on a blood agar culture plate. Also known as Salmonella arizonae, it is a zoonotic bacterium that can infect humans, birds, reptiles, and other animals. (CDC)

www.chromagar.com

Rambach™ Agar For detection of Salmonella spp. •Salmonella - red•other bacteria - blue, violet, colourless, or inhibited.

wqc

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Isolation of Salmonellafrom Environmental Samples

www.textbookofbacteriology.netSalmonella typhimurium HE agar

Enterobacteriaceae


Klebsiella groupEnterobacterEdwardsiellaCitrobacter



ETEC (enterotoxisch)EPEC (enteropathogene)EIEC (enteroinvasive)EHEC (enterohemorrhagisch)EAggEC (enteroaggregativ)




Shigella

S. dysenteriae* 10 SerotypesS. flexneri* 6 SerotypesS. boydii 15 SerotypesS. sonnei

AntigenO

* Toxin

Shigella sonnei

Shigella

Virulence factorsExotoxincytotoxic (cell lysis!);Enterotoxic;Paralytic – letal activity

Fragment A, B (5) – Glycolipid

Inhibition of Proteinsynthesis – Binding andInactivation of 60s Ribosom subunit cell death

OMP (Ipa, Ics)Endotoxin - LPS

Pathogenicity – ID50: 100-200 BacteriaEntry and multiplication in Epithel cells:Invasion Plasmid Antigens – IpaIntercellular Spread – Ics

Pathogenesis, clinical findingsLocal InfectionEpithel necrosis, ulcerationinhibiting AbsorptionHUS!

Shigella

Medmicro

Shigella

mgc.ac.cn/VFs/Figures/Shigella

Shigella

Fig. 2: Shigella Passing Through the Mucous Membrane and …

… Invading Mucosal Epithelial Cells

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Fig. 4.33 Shigellosis. Sigmoidoscopic view of colonic mucosa in a mild case of infection due to S. flexneri. Note the thin whitish exsudate, which is made up of fibrin and polymorphonuclearleucocytes. By courtesy of Dr. R.H. Gilman.

Fig. 4.34 Shigellosis. Sigmoidoscopic view of colonic mucosa in a fatal case of infection with S. dysenteriaetype 1 showing extensive pseudomembranous colitis. By courtesy of Dr. R.H. Gilman and Dr. F. Koster.

Fig. 4.18 Positive Serény test. Keratoconjunctivitis in the rabbit produced by the instillation of shigella microorganism. By courtesy of Dr. H.L. DuPont.


Shigella

DiagnosisDirect detection(from stool)

Differentiating –SelectiveMedia

Identification Serotyping

Shigella boydii colonies on blood agar

www.biologie.de

Appearance of Colonies on Salmonella-Shigella Agar

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A. Klebsiella pneumoniae B. Escherichia coliKlebsiella pneumoniae & Escherichia coli are positive for acid production from fermentation of the carbohydrate(s) present.

C: Salmonella sp.

D: Proteus mirabilis

Both Salmonella sp. & Proteus mirabilis product hydrogen sulfide. E: Pseudomona aeruginosa

The

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Shigella

ProphylaxisExpositions prophylaxis – Hygienic rules

TherapyAntibiogramTetracylin, Ampicillin, Chloramphenicol, Sumetrolim

Enterobacteriaceae


Klebsiella groupEnterobacterEdwardsiellaCitrobacter



ETEC (enterotoxic)EPEC (enteropathogenic)EIEC (enteroinvasive)EHEC (enterohemorrhagic)EAggEC (enteroaggregativ)




Yersinia enterocolitica

Morphology Gram negative,bipolar rods

flagellae

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Yersinia enterocolitica www.ktl.fi

cultivationoptimum 28°C, motility 28°C

Y. enterocoliticaO:5,27 CIN-ag

www.szu.czBlood agar

AntigensO and H

Y. enterocoliticade.wikipedia.org

Figure 29-7 Pathogenesis of Y. enterocolitica.

Clinical findingEnterocolitisLymphadenitis mesenterica

DiagnosisDirect detectionSerologySerotyping

TherapyTetracyclinChloramphenicolSumetrolim

Yersinia pseudotuberculosis

MorphologyGram negative, bipolar rodsflagellae

Cultureeasy, grow 37°C and 20°Cmotility 20°C

PathogenicityPseudotuberculosis ofrodents

Source of infection:Sick animalsPortal of entry: mouth, mucosa Y. pseudotuberculosis

www.microbes-edu.org

Yersinia pseudotuberculosis

Clinical findingsLymphadenitis mesentericaSeptic-typhoid FormEnteritis

DiagnosisDirect detectionSerotyping – AgglutinationSerology

TherapyTetracyclin

Fig. 4.50 Yersinia infection. Gross specimen of ileum, showing superficial necrosis of the intestinal mucosa with several well-defined deep and superficial ulcers.

www.llnl.gov

Y. pseudotuberculosis


Vibrionaceae

GRAM NEGATIVE RODS









watery diarrhea







Typhus, Sepsis



Gram negative facultative anaerobic rods(Positive Glucose fermentation)

Oxidase positive Oxidase negative

Vibrionaceae Aeromonadaceae

Vibrio Aeromonas

Enterobacteriaceae

EscherichiaKlebsiella

EnterobacterProteusSerratia

ProvidenciaMorganella

EdwardsiellaCitrobacter

Hafnia

SalmonellaShigellaYersinia

Facultativepathogenic

Obligatepathogenic

Plesiomonas

V. choleraeV. parahaemolyticusV. vulnificus

P. shigelloides A. hydrophila

VibrionaceaeSpecies Associated diseases

V. cholerae O1klassische & El Tor Cholera

V. cholerae O139 Cholera

V. parahaemolyticus Gastroenteritis

V. vulnificus Wound infection, sepsis

Non-agglutinable(NAG) vibrios Gastroenteritis (rarely)

R. Koch, 1883Morphology• Gr–, curved rods• Facultative anaerobesBiochemical reactionsGlukose OF ‡Motility +Catalase +Oxidase +Nitrate Reduction +

Vibrio cholerae

bepast.org

V. cholerae

Antigen structure, virulence factorsO (cell wall) - 138O1 & O139H flagellar (common)Fimbriae: A, B, CO1: Bio and Serotypes

V. cholerae

Vibrio cholerae. Leifson flagella stain (digitally colorized). CDC/Dr. William A. Clark


Bio- & Serotypes of V. cholerae O1

Medmicro

Virulence factors

Virulence factor Biologic effect

Cholera toxin Fluid & electrolytehypersecretion

Fimbriae Adhesion to mucus membrane

Accessory colonisation factor Adhesion to mucus membrane

Haemagglutination protease (mucinase)

Enteric inflammationdegradation of tight junctions

Siderophores Iron sequestration

Neuraminidase Toxin receptor up-regulation

V. cholerae

Pathogenesis – Obligate human pathogenSource of infection: 1. humans (sick) and carriers(incubation, constant carriers and reconvalescent carriers – via stool! – flies!)2. Contaminated food (sea food!) and drinking waterReservoir: Algae, Mussel, PlanktonsTransmission: Per oralPortal of entry: GI

Toxin building in small intestineNO DISSEMINATION!Clinical finding, disease: Cholera – due to Cholera toxin

Immunity: local IgA (IgG in blood!)

Adhaesion of V. cholerae to intestinal epithelium

TEM, ×16.000SEM, ×4.000

Medmicro ch 24

FIGURE 24-1 Pathophysiology of cholera.

textbookofbacteriology.net

Cholera toxin: mode of action

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1. 2.

3.

4.

Cholera Toxin and Pertussis Toxin

Cholera Pandemies• India, estuarine of Ganges• Intercontinental travels, trading, wars ⇒

seven pandemics from 1817• At present: 7th pandemic, V. EL Tor

– 1961: Asia– 70’s–80’s: Africa, Europe, Oceania– 1991: South-America

• 1992 : V. cholerae O139 „Bengal”– Rapid spread (Asia, Europe, USA)– No cross immunity with O1-strains– 8th pandemic?

7th Cholera Pandemy 1961

Cholera cases, WHO: 2000–2001

Cholera outbreaks

Cholera camp in Mozambique

Cholera clinic in Mozambique

Cholera: clinical picture• rice- - water diarrhoea

(25 L/day)• Dehydration• Haemoconcentration• Blood pH • Serum K+ , Na+

• Serum Glucose ↑• Shock• Letality

– Untreated• Classical: 60%• El Tor: 15–30%

– Treated: 1%

Rice-water diarrhoea

Baby before and afterrehydration

Cholera Beds

• Patients history!• specimen: stool• Direct microscopy:

dark field microscope

Diagnosis

Transport: Alkaline PeptonwaterCulture: TCBS medium

Diagnosis

IdentificationBiochemical Reactions

Serotyping (O1, O139)

Antibiogram

Diagnosis

V. cholerae

Prophylaxis of Cholera

Expositions prophylaxisClean drinking water! – and food hygiene and sewage water system – no mix with drink water!

Mass education, adhering to hygienic rulesIsolation; Quarantinetreating, disinfectingWater boilingFollow up carriersReport to WHO

• Immune prophylaxisVaccination

– Vaccine (against O1 ony)• Killed bacterium, parenteral• Killed bacterium + B-subunit Toxoid per os• Gene manipulated, attenuated V. cholerae per os

– Protection of 3–6 month, efficacy 50–60%– Travellers to endemic areas– WHO: false feeling of security (!)

Prevention of cholera: mass education of hygienic rules

Therapy of Cholera

Salt-sticks

Coke

Therapy of Cholera

• Fluid and electrolyte substitution– Intravenous– Per os Oral Rehydration Fluid

ORF• Glucose 20g/l• NaHCO3: 2,5 g/l• NaCl: 3,5 g/l• KCl: 1,5 g/l

• Antibiotic– Ciprofloxacin– Doxycycline

Peru

Bangladesh

Vibrio parahaemolyticus

www.city.niigata.niigata.jp

www.fehd.gov.hk

Gastroenteritis

Fig. 10.20 Cellulitis. Severe infection with bullous lesions due to V. vulnificus infection following immersion of leg in brackish water.

V. vulnificus

V. vulnificus

Fig. 10.21 Vibrio cellulitis. Haemorrhagic, bullouslesions of V. vulnificussepsis. By courtesy of Dr. J.R. Cantey

A. hydrophila P. shigelloides

Cellulitis Myonecrosis

A. hydrophila infection in fish

Gastroenteritis

Sea food

Natural water sources

web.umr.edu

Aeromonas hydrophila

www.buddycom.com

www.buddycom.comweb.umr.edu


Plesiomonas shigelloideshttp://www.vetmed.wisc.edu

To be continued…

Zakynthos, 2004

Microaerophilic Gram negative rods –

Campylobacter andHelicobacter

GRAM NEGATIVE RODS









watery diarrhea







Typhus, Sepsis



Spiral formed & curvedGram-negative bacteria

Spirillaceae

Campylobacter Helicobacter Spirillum

C. jejuni H. pylori S. minus

Most important species of Campylobacter genus

Species Reservoir Diseases Frequency

C. C. jejunijejuni Poultry, pig, cattle, rabbit

Gastroenteritis, sepsis, meningitis, Guillan-Barré

Frequent

C. coli Pig, poultry, cattle, sheep

Sepsis, gastroenteritis, meningitis

Uncommon

C. fetus Cattle, sheepSepsis, gastroenteritis, meningitis

Uncommon

C. lari Poultry, pig, cat, monkey, horse

Gastroenteritis, sepsis Rare

C. upsalensis Dog, cat Gastroenteritis, sepsis, abscess ?

Campylobacter

MorphologyGram negative curved rods (0,3–0,6 μm)

Campylobacter

Polar flagellum

Transmission electron micrographs of Campylobacter jejuni, negatively stained to enhance contrast.

www.wadsworth.org

www.shef.ac.uk Campylobacter jejuni

www.indigo.com

Campylobacter jejuni

CultureMicroaerophilic

5–7% O25–10% CO2

Thermophilic: 42ºC

Campylobacter

Campy-blood-agarmedinfo.ufl.edu

www.biomerieux.com

Special media

Campylobacter C. jejuni, SEM

C. jejuni, SEM

Biochemical reactionsNon-fermenting • Catalase +, Oxidase +• Nitrate reduction +• Antigen Structure

– O, H, K (Serotyping)

Virulence factors• flagellum ⇒ motility• Adhaesion Factors• Invasion Factors (?)• Cytotoxin• C. fetus: S-Protein ⇒ inhibition of binding of C3b ⇒

antiphagocytic effect• LPS

Complication:• Guillan-Barré SyndromeSimilar structure: LPS-core and glycosphingolipids of

Gangliosids (GM1, GM2) ⇒Antibodies against GM1 ⇒Autoimmun process ⇒ Demyelinisation

Campylobacter

C. coli & Guillan-Barré syndrome

Epidemiology

• Zoonotic infection!• Source of infection:

contaminated food & waterInsufficient heat on meat• Human to human: Faecal-oral

route (children). Rarely• ID: 500 (low)• Very common (in developing

countries 80% of diarrhealdiseases)

Campylobacteriosis: Clinical picture

• Incubation: 1–2 days• Bloody diarrhoea• Fever• Abdominal pain, cramps• Spontaneous healing:

within 1–7 days• Complications

– Prolonged course– Systemic infection– Reactive arthritis– Guillan-Barré syndrome

Diagnosis of Campylobacter Infections

Campylo-agarculture

Biochemical identification

• Sample– Faeces– Blood culture, CSF– Food

• Culture (microaerophilic, thermophilic)• Identification• Antibiotic susceptibility test

Therapy & Prevention of Campylobacter Infections

• Supportive (water, electrolytes)• Antibiotic therapy

– Gastroenteritis• Erythromycin, Doxycycline, Ciprofloxacin,

Amoxicillin/clavulanic acid– Systemic infection

• Carbapenem, Aminoglycoside, Chloramphenicol

• Prevention: food hygiene

Helicobacter pyloriMorphology• Gram negative, spiral-

formed rod

Polar flagellae: Motility

Culture• MicroaerophilicBiochemical reactions• Non-fermenting• Catalase +• Oxidase +• Urease + (!)

H. pylori

Virulence factors of H. pylori• Adhaesins (HOP)• Flagellae (Motility)• Mucinase, phospholipase• Urease activity• Vacuolating cytotoxin• Protein CagA

Translocation viaType IV. Secretion-systemchanging cytoskeletonIl-8, Il-1, TNFα Stimulation

Urease positive

Cytotoxic effect in HeLa cells

Epidemiology and clinical findings ofH. pylori Infections

Epidemiology• Common worldwide• Reservoir: humans• Transmission

– Faecal-oral– Oro-oral (saliva)– Endoscope!

Clinical pictureAcute GastritisChronic-active GastritisGastroduodenal UlcusTumor

H. pylori & peptic ulcer

Chronic gastritis

Duodenal ulcer

H. pylori on gastric mucosa, SEM

H. pylori histology, silver impregnation

H. pylori & gastric carcinoma

Antral adenocarcinomagastroscopic finding

Gastric adenocarcinoma withliver metastasis & ascites

Diagnosis of H. pylori

• direct detection of Helicobacter Antigen in stool sample• biopsy: Histopathology, culture, molecular biology (PCR)• radioactive Urea expiration test• serology: AB detection

Radioactive Urea expiration test

Microbiological Diagnosis of H. pylori

H. pylori culture

Biochemical identification

H. pylori ELISA (IgG, IgA)

H. pylori Western blot

culture –Biopsy Material

antibodies – Blood serum

H. pylori Eradication

• Combinations - Therapy with– Proton pump inhibitors– Antibiotics

• Clarithromycin + Metronidazole• Amoxicillin + Metronidazole• Doxycycline + Metronidazole

– Eradication: 90%

THE END

Santorini, 2009

Normal bacterium Flora of the Gastrointestinal tract

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