salmonella by akram.ppt - mmc.gov.bd file/salmonella by akram.pdffrom faeces of hog cholera in...

SalmonellaSalmonella

Prof. Md. Akram HossainProf. Md. Akram Hossain

11Prof. Muhammad Akram Hossain, Prof. Muhammad Akram Hossain, SalmonellaSalmonella

��AnAn estimatedestimated 2222 millionmillion casescases ofoftyphoidtyphoid feverfever andand 200200,,000000 relatedrelateddeathsdeaths occuroccur worldwideworldwide eacheach yearyear..

�� InIn Bangladesh,Bangladesh, thethe overalloverall incidenceincidenceofof typhoidtyphoid feverfever isis 390390 casescases perper100100,,000000 populationpopulation annuallyannually.. ii..ee..66..00 lakhlakh perper yearyear


IntroductionIntroduction

�� EbrethEbreth firstfirst inin 18801880 && GaffkeyGaffkeysubsequentlysubsequently fromfrom typhoidtyphoid feverfever inin18841884 soso namednamed asas EbrethellaEbrethella typhityphi

�� SalmonSalmon && SmithSmith firstfirst isolatedisolated thethe bacillusbacillusfromfrom faecesfaeces ofof HogHog choleracholera inin 18851885..fromfrom faecesfaeces ofof HogHog choleracholera inin 18851885..

�� NormallyNormally residesresides inin thethe coloncolon ofofvertebratesvertebrates andand pathogenicpathogenic forfor humanshumans &&manymany animalsanimals•• poultry,poultry, pigs,pigs, rodents,rodents, cattle,cattle, parrotsparrots

�� CauseCause entericenteric feverfever (Typhoid(Typhoid &&paratyphoidparatyphoid fever),fever), foodfood poisoningpoisoning &&septicemiasepticemia 33Prof. Muhammad Akram Hossain, Prof. Muhammad Akram Hossain,


TaxonomyTaxonomy�� There more than 2500 serotypes, of which >1400 can cause There more than 2500 serotypes, of which >1400 can cause

human infectionshuman infections

�� Broad host rangeBroad host range

�� Highly adapted to human infectionsHighly adapted to human infections

•• S. typhi, S. paratyphi A, S. paratyphi B, S. paratyphi CS. typhi, S. paratyphi A, S. paratyphi B, S. paratyphi C

•• S. typhimurium, S. enetritidis, S. newport, S. dublinS. typhimurium, S. enetritidis, S. newport, S. dublin•• S. typhimurium, S. enetritidis, S. newport, S. dublinS. typhimurium, S. enetritidis, S. newport, S. dublin

•• S. cholerasuisS. cholerasuis

�� 3 methods of nomecnclature3 methods of nomecnclature

•• Ewing Ewing –– 3 species (S. typhi, cholerasuis & enteritidis with many 3 species (S. typhi, cholerasuis & enteritidis with many

subspecies)subspecies)

•• Kauffmann White Kauffmann White –– O & H antaigen, 64 “O” groups (AO & H antaigen, 64 “O” groups (A--Z, 15Z, 15--64)64)

•• DNA hybrdization analysisDNA hybrdization analysis


Morphology & cultural characters Morphology & cultural characters

Motile with peritrichous flagella except Motile with peritrichous flagella except S.pullorumS.pullorum & & S.gallinarumS.gallinarum

GNB 2GNB 2--4 umx0.6 um4 umx0.6 um

��Lactose non Fermenter i.e. Lactose non Fermenter i.e. form pale colonies in MA form pale colonies in MA medium. Grows in selective medium. Grows in selective media like SSA, Selenite or media like SSA, Selenite or tetrathionate brothtetrathionate broth 55Prof. Muhammad Akram Hossain, Prof. Muhammad Akram Hossain,


BiochemistryBiochemistry

Biochemistry:Biochemistry:

�� Do not Ferment Lactose, sucrose,Salicin Do not Ferment Lactose, sucrose,Salicin

�� Ferments Glucose, Maltose, Mannitol Ferments Glucose, Maltose, Mannitol

�� Negative for Indole and positive for methyl red reaction.Negative for Indole and positive for methyl red reaction.�� Negative for Indole and positive for methyl red reaction.Negative for Indole and positive for methyl red reaction.

�� Most strains produce H2S (except S. paratyphi A & Most strains produce H2S (except S. paratyphi A &

cholerasuis)cholerasuis)

•• LSS LSS -- -- --

•• GMM +++GMM +++

•• IMViC IMViC -- + + -- --


SalmonellaSalmonella SerologySerology

�� SalmonellaSalmonella can be subdivided by somatic can be subdivided by somatic

(cell(cell--wall) or O antigens and flagellar or H wall) or O antigens and flagellar or H

antigens. antigens.

•• “O” >65 types, less immunogenic than H, “O” >65 types, less immunogenic than H, •• “O” >65 types, less immunogenic than H, “O” >65 types, less immunogenic than H,

IgMIgM

•• “H” two types phase 1 & phase 2, more “H” two types phase 1 & phase 2, more

immunogenic & long lasting, IgG.immunogenic & long lasting, IgG.

�� Clinical importance: Titer of “H” is more than Clinical importance: Titer of “H” is more than

“O”“O”77Prof. Muhammad Akram Hossain, Prof. Muhammad Akram Hossain,


Virulence factorsVirulence factors

1.1. InvasivenessInvasiveness

2.2. EndotoxinEndotoxin

�� Posess LPS endotoxin characteristic of GramPosess LPS endotoxin characteristic of Gram--

negative bacterianegative bacterianegative bacterianegative bacteria

•• composed of an "O” polysaccharide ("O" antigen)composed of an "O” polysaccharide ("O" antigen)

•• "R" core"R" core

•• endotoxic inner "Lipid A". endotoxic inner "Lipid A".

•• Endotoxins evoke fever and can activate Endotoxins evoke fever and can activate

complement, kinin and clotting factors.complement, kinin and clotting factors.


Structure of a GramStructure of a Gram--Negative Cell WallNegative Cell Wall


Summary of EndotoxinSummary of EndotoxinLPS

LPS-LBP

CD14

TLR4

Circulation

Details of endotoxin

TLR4

TNFα

Fever tissue damage IL6 IL8 IL1 PAF

Toxic shock

Macrophages


Salmonella IllnessSalmonella IllnessClinical infections caused by salmonella varies with different Clinical infections caused by salmonella varies with different

species or serotypes species or serotypes 1.1. Gastroenteritis or salmonellosisGastroenteritis or salmonellosis

�� S. enteritidisS. enteritidis most commonly isolated species, most commonly isolated species, S.typhimurium, S. S.typhimurium, S. dublindublin

�� contaminated food or water. Most commonly, contaminated food or water. Most commonly, �� often from contaminated poultry (turkeys and chickens). often from contaminated poultry (turkeys and chickens).

2.2. Enteric fever:Enteric fever:�� S. typhiS. typhi (no animal reservoirs), S.paratyphi A, B, C (have animal (no animal reservoirs), S.paratyphi A, B, C (have animal

reservoirs)reservoirs)�� transmitted from person to person and involves transmitted from person to person and involves �� reservoirs: reservoirs:

•• Contaminated food or water with human fecesContaminated food or water with human feces•• asymptomatic human carriersasymptomatic human carriers

3.3. SepticemiaSepticemia�� By S. cholerasuisBy S. cholerasuis


Epidemiology

- Salmonella gastroenteritis due to eatingcontaminated food, often chicken andturkeys, but also pigs and cows- meats and animal products (eggs) notthoroughly cooked are main source ofthoroughly cooked are main source ofinfections- 20-40,000 cases/yr in USA- typhoid fever - no animal reservoir, humancarriers who contaminate food and water;400-500 cases/yr in USA


After binding to cell receptorsbacteria taken in by endocytosisbut do not escape endosome..

Pathogenesis of Salmonella enteritidis


Salmonella Enetritidis


Enteric fever


Salmonella typhi, paratyphi A, B, C

Small intestine

Attach, invade epithelial cells & engulfed by MPS where they multiply

Released into blood via thoracic duct– Primary bacterimia

7 -10 days

Pathogenesis of enteric fever

Cleared from blood by MPS and will lodge in liver, spleen, lung, Lymph node

7 -10 days

Parasitized cells undergoes necrosis & bacilli heavily reinvade blood

Secondary heavy bacterimia Clinical illness

Occurs at 14th days of infectionLocalized to gall bladder, liver, spleen etc

From gallbladder to payers patches of intestine-hemorrhage, ulcer1616Prof. Muhammad Akram Hossain, Prof. Muhammad Akram Hossain,


First time2nd time

Pathogenesis of typhoid fever1717Prof. Muhammad Akram Hossain, Prof. Muhammad Akram Hossain,


Invasion of M cells by Salmonella leads to destruction of M cell andperforation of intestinal lining. Persistence within phagocytes is basisfor systemic spread of organism. 1818Prof. Muhammad Akram Hossain, Prof. Muhammad Akram Hossain,


Clinical manifestationsGastroenteritis

6-48h incubation, then nausea, vomiting and diarrhea with fever and chills; lasts 2-7 d

Enteric Fevers10-14 d incubation; gastroenteritis may preceed

enteric fever; enteric fever; high sustained fever, malaise, anorexia,headache and myalgias; complications include intestinalobstruction, severe bleeding, cholecystitis, sepsis, etc.

Approximately 30% of typhoid patients may have rose spots – a faint salmon-colored maculopapular rash on the trunk; organismscan be cultured from punch biopsies of these lesions, and thepathology is characterized as a perivascular mononuclear cell infiltrate


Evolution of Typical Symptoms and Signs of Evolution of Typical Symptoms and Signs of Typhoid FeverTyphoid Fever

Disease period

1st weak

Symptoms Signs Pathology

Fever, chills gradually increasing and persisting , headache

Abdominal tenderness

Bacteremia

2nd weak

3rd weak

4th weak

And later

Rash, abdominal pain, diarrhea or constipation, delirium, prostration

Resolution of symptoms, relapse, Weight loss

Complication of intestinal bleeding and perforation, shock

Rose spots,Splenomegaly, Hepatomegaly

Melena, ileus,

rigid abdomen, coma

Reappearance of acute disease, cachexia

Mononuclear cell vasculitis of skin, hyperplasia of ileal Peyer’s patches, typhoid nodules in spleen and liver

Ulcerations over Peyer’s patches, perforation with peritonitis

Cholecystitis, chronic fecal carriage of bacteria


““rose spotsrose spots””a faint, salmona faint, salmon--colored, blanching, maculopapular rash colored, blanching, maculopapular rash

located primarily on the trunk and chest.located primarily on the trunk and chest.


Late complicationsLate complicationsin the third and fourth weeksin the third and fourth weeks

�� intestinalintestinal perforationperforation and/orand/or gastrointestinalgastrointestinalhemorrhagehemorrhage..

�� lifelife--threatening,threatening, requirerequire immediateimmediate medicalmedical andand�� lifelife--threatening,threatening, requirerequire immediateimmediate medicalmedical andandsurgicalsurgical interventions,interventions, withwith broadenedbroadened antibioticantibioticcoveragecoverage forfor polymicrobialpolymicrobial peritonitisperitonitis andandtreatmenttreatment ofof gastrointestinalgastrointestinal hemorrhages,hemorrhages,includingincluding bowelbowel resectionresection..


The incidence of chronic carriageThe incidence of chronic carriage

�� ChronicChronic carriercarrier:: TyphoidTyphoid feverfever�� HigherHigher amongamong womenwomen && amongamong personspersons

withwith biliarybiliary abnormalitiesabnormalities (e(e..gg..,, gallstones,gallstones,carcinomacarcinoma ofof thethe gallbladder)gallbladder) andandgastrointestinalgastrointestinal malignanciesmalignancies..carcinomacarcinoma ofof thethe gallbladder)gallbladder) andandgastrointestinalgastrointestinal malignanciesmalignancies..

�� TheThe anatomicanatomic abnormalitiesabnormalities associatedassociatedwithwith thesethese conditionsconditions presumablypresumably allowallowprolongedprolonged colonizationcolonization..


Principle: is based on isolation of the Salmonella spp. by blood culture &culture of stool etc also by immunological test i.e. detection of antibody(widal test) and antigen (recently introduced). Detection of DNA byMolecular tests lke PCR. Tests of choice varies with duration of illness.Blood culture and antigen detection is reliable in the fist week and widaltest is helpful in 2nd week onwards. PCR is helpful 1st week onwards.

Steps:Specimen: Blood, Bone marrow for culture, Ag Detection

Lab Dx of Enteric fever

Specimen: Blood, Bone marrow for culture, Ag Detection& PCR in 1st week and for Antibody test in 2nd week..M/E : is not helpful.

Isolation & identification (Culture): Blood culture can bedone in three processes -

Traditional - using liquid media or biphasic mediaLytic method - after processing in lytic solution directly in solid mediaAutomated - very rapid (within 6 hrs)

Immunological test : Widal test for Ab detection & Agdetection, Dot ELISA for IgMPCR


�� OtherOther thanthan aa positivepositive culture,culture, nono specificspecificlaboratorylaboratory testtest isis diagnosticdiagnostic forfor entericenteric feverfever..

�� leukopenialeukopenia && neutropenianeutropenia ,, thethe whitewhite bloodblood cellcell countcountisis normalnormal despitedespite highhigh feverfever..

�� leukocytosisleukocytosis cancan developdevelop (especially(especially inin children)children)

Lab Dx of Enteric fever..

�� leukocytosisleukocytosis cancan developdevelop (especially(especially inin children)children)duringduring thethe firstfirst 1010 daysdays ofof thethe illness,illness, oror laterlater ifif thethediseasedisease coursecourse isis complicatedcomplicated byby intestinalintestinalperforationperforation oror secondarysecondary infectioninfection..

�� liverliver functionfunction teststests�� electrocardiogramselectrocardiograms..


The diagnostic "gold standard"The diagnostic "gold standard"

�� Isolation of organismIsolation of organism


Isolation of organismIsolation of organism

�� a blood culture positive for a blood culture positive for S. typhiS. typhi or or S. paratyphiS. paratyphi. .

-- as high as 90% during the first week as high as 90% during the first week

-- decrease to 50% by the third week. decrease to 50% by the third week.


�� Bone marrow cultures Bone marrow cultures

: highly (90%) sensitive despite 5 days of : highly (90%) sensitive despite 5 days of

antibiotic therapy. antibiotic therapy.


�� Culture of intestinal secretions (best obtained by a Culture of intestinal secretions (best obtained by a noninvasive duodenal string test) noninvasive duodenal string test)

: can be positive despite a negative bone marrow : can be positive despite a negative bone marrow culture. culture.


Widal’s reactionWidal’s reactionWidal’s testWidal’s test

��

Associated persons:Associated persons:Max von GrubeMax von GrubeGeorges Fernand Isidore WidalGeorges Fernand Isidore Widal

Description:Description:Serological agglutination test for typhoid fever.Serological agglutination test for typhoid fever.

The test is based on the presence of agglutinating The test is based on the presence of agglutinating antibodies against paratyphoid bacteria in the patient’s antibodies against paratyphoid bacteria in the patient’s serum. It is mainly used for indirect confirmation of serum. It is mainly used for indirect confirmation of salmonellosis (as against typhus abdominalis, paratyphus, salmonellosis (as against typhus abdominalis, paratyphus, and brucelloses), but also for diagnosing infectional and brucelloses), but also for diagnosing infectional diseases like shigelloses, tularaemia and spotted fever. diseases like shigelloses, tularaemia and spotted fever.

Bacterial agglutination was discovered by Bacterial agglutination was discovered by Max von Max von Gruber and Herbert Edward DurhamGruber and Herbert Edward Durham (1866(1866--1945). 1945).

�� It was first briefly reported by Durham, and then described It was first briefly reported by Durham, and then described by Gruber and Durham. Their discovery was the basis for by Gruber and Durham. Their discovery was the basis for Widal’s test for typhoid. Widal’s test for typhoid.


�� IfIf blood,blood, bonebone marrow,marrow, andand intestinalintestinal secretionssecretions areare allall

cultured,cultured, thethe yieldyield ofof aa positivepositive cultureculture isis >>9090%%..

�� StoolStool cultures,cultures,

-- negativenegative inin 6060 toto 7070%% ofof casescases duringduring thethe


-- negativenegative inin 6060 toto 7070%% ofof casescases duringduring thethe

firstfirst week,week,

-- positivepositive duringduring thethe thirdthird weekweek ofof infectioninfection inin

untreateduntreated patientspatients..


QQ.. WhatWhat isis entericenteric fever?fever? WhyWhy itit isis soso called?called?NameName teststests usedused forfor diagnosisdiagnosis inin thethe 11ststweekweek ofof illnessillness..

AnsAns:: EnetricEnetric feverfever isis aa systemicsystemic illness,illness,manifestedmanifested byby feverfever andand otherother symptomssymptomsandand causedcaused byby SalmonellaSalmonella typhi,typhi, SS..paratyphiparatyphi A,A, SS.. paratyphiparatyphi B,B, && SS..paratyphiparatyphi CC.. TheyThey areare soso calledcalled becausebecauseparatyphiparatyphi A,A, SS.. paratyphiparatyphi B,B, && SS..paratyphiparatyphi CC.. TheyThey areare soso calledcalled becausebecausetheirtheir mainmain lesionlesion occursoccurs inin thethe intestineintestine(( payerspayers patches)patches)..

BloodBlood cultureculture andand detectiondetection ofof salmonellasalmonellaantigenantigen fromfrom thethe bloodblood andand otherotherspecimensspecimens areare thethe reliablereliable teststests usedused forfordiagnosisdiagnosis inin thethe firstfirst weekweek ofof illnessillness..


Widal testWidal test--11

�� What is widal test?What is widal test?•• It is a serological test for detection of It is a serological test for detection of

antibodies against S. typhi, S.paratyphi A, Bantibodies against S. typhi, S.paratyphi A, B

�� Which antibodies ?Which antibodies ?•• “O” & “H” antibodies“O” & “H” antibodies•• “O” & “H” antibodies“O” & “H” antibodies•• TO= Somatic antibody of S. typhi, TO= Somatic antibody of S. typhi,

•• TH= Flagellar Antibody S.typhi TH= Flagellar Antibody S.typhi

•• AO= Somatic antibody S. paratyphi A,AO= Somatic antibody S. paratyphi A,

•• AH= Flagellar antibody of S.paratyphi A AH= Flagellar antibody of S.paratyphi A

•• BO= Somatic antibody S. paratyphi B,BO= Somatic antibody S. paratyphi B,

•• BH= Flagellar antibody of S.paratyphi BBH= Flagellar antibody of S.paratyphi B


Widal testWidal test--11

�� What is the role in the diagnosis of What is the role in the diagnosis of enteric fever?enteric fever?•• It is helpful It is helpful

�� where culture facilities is not availablewhere culture facilities is not available

When patient comes late ( 2When patient comes late ( 2ndnd week)week)�� When patient comes late ( 2When patient comes late ( 2ndnd week)week)

�� When patient takes antibioticsWhen patient takes antibiotics

�� If interpreted cautiouslyIf interpreted cautiously

�� Epidemiological importantEpidemiological important


History of widal testHistory of widal test

�� GeorgesGeorges FernandFernand IsidoreIsidore WidalWidal aafrenchfrench physicianphysician discovereddiscovered inin 18961896

�� InIn 18961896 WidalWidal developeddeveloped aa procedureprocedure forfor diagnosingdiagnosingtyphoidtyphoid feverfever basedbased onon thethe factfact thatthat antibodiesantibodies inin thethe bloodbloodtyphoidtyphoid feverfever basedbased onon thethe factfact thatthat antibodiesantibodies inin thethe bloodbloodofof anan infectedinfected individualindividual causecause thethe bacteriabacteria toto bindbind togethertogetherintointo clumpsclumps (the(the WidalWidal reaction)reaction)..

�� DuringDuring WorldWorld WarWar I,I, WidalWidal preparedprepared anan antityphoidantityphoid--paratyphoidparatyphoid vaccinevaccine thatthat appreciablyappreciably reducedreduced typhoidtyphoidcontagioncontagion amongamong thethe alliedallied armiesarmies..


TO =1:80

TH = 1:80

AO = 1:80AH = 1:80

BO = 1:80BH = 1:80

Titer

1:640

Widal test

1st

week2nd week 3rd week

Days of illness

1:160

1:320


What is the interpretation of widal test?What is the interpretation of widal test?

�� Following points must be considered for Following points must be considered for interpretation of widal testinterpretation of widal test•• “O” antigen “O” antigen –– is somatic, sharing, is somatic, sharing,

Polysaccharide, weak, TPolysaccharide, weak, T-- independent independent

•• “H” antigen “H” antigen –– flagellar, specific, protein, strong, flagellar, specific, protein, strong, TT-- dependantdependantTT-- dependantdependant

•• Antibodies develop after 2Antibodies develop after 2ndnd week of illnessweek of illness

•• Local titer ( titer in the healthy population) Local titer ( titer in the healthy population) varies from region to region varies from region to region –– TO,TH,AO, AH = TO,TH,AO, AH = 1:80,BO,BH=1:401:80,BO,BH=1:40

•• “Rising titer” rather than single high titer is “Rising titer” rather than single high titer is diagnosticdiagnostic

•• Effect of early administration of antibioticEffect of early administration of antibiotic

•• Administration of vaccine Administration of vaccine 3636Prof. Muhammad Akram Hossain, Prof. Muhammad Akram Hossain,


How will you interpret widal test?How will you interpret widal test?

1.1. Any high titer before Any high titer before 22ndnd week is to be week is to be interpreted cautiously.interpreted cautiously.

2.2. Very High Single titer either of “O” or “H” Very High Single titer either of “O” or “H” ((11::320320) is ) is significant.significant.

3.3. Rising titer with paired samples (done Rising titer with paired samples (done 55--10 10 days apart) is days apart) is diagnostic.diagnostic.10 10 days apart) is days apart) is diagnostic.diagnostic.

4.4. Anamnestic reaction can occur and is Anamnestic reaction can occur and is manifested by moderately high titer of manifested by moderately high titer of only “H”only “H”

5.5. Early use of antibiotics hamper with rise of Early use of antibiotics hamper with rise of antibody titer.antibody titer.

6.6. Even after successful treatment high titer Even after successful treatment high titer persists for persists for 33--6 6 weeks.weeks.


Treatment

Gastroenteritis – Supportive, no antibiotics

Typhoid fever1st choice – Fluroquinolone or 3rd1 choice – Fluroquinolone or 3rd

generation cephalosporins - for 14 daysAzithromycin for 7-10 days

Septicemia or enteric fevers =Parenteral with double dose


Prevention

� Fluoroquinolones to treatcarriers of S. typhi (1-3% ofinfected pts may

become carriers, usually bacteriabecome carriers, usually bacteriain gallbladder)

� public health sanitationstandards

� Typhoid vaccine - Typehrix


Review questionsReview questions�� What type of bacteria is Salmonella?What type of bacteria is Salmonella?�� What is its clinical importance? What is its clinical importance? �� Name the diseases caused by Salmonella spp.Name the diseases caused by Salmonella spp.�� Name some clinically important salmonella spp.Name some clinically important salmonella spp.�� What is enteric fever? Why it is so called?What is enteric fever? Why it is so called?�� Pathogenesis of Enteric fever?Pathogenesis of Enteric fever?�� How can you diagnose enteric fever if the patient comes in a) How can you diagnose enteric fever if the patient comes in a)

11stst week b) week b) 22ndnd week?week?11 week b) week b) 22 week?week?�� What is the gold standard test for diagnosis of Enteric fever?What is the gold standard test for diagnosis of Enteric fever?�� What is blood culture? Short notes on Blood culture. What are What is blood culture? Short notes on Blood culture. What are

the other specimens that can be cultured for diagnosis of the other specimens that can be cultured for diagnosis of enetric fever?enetric fever?

�� What is widal test? Which antibodies are detected? What is its What is widal test? Which antibodies are detected? What is its clinical importance clinical importance

�� Interpretation of widal test?Interpretation of widal test?


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