SalmonellaSalmonella

Enterobacteriaceae 3Enterobacteriaceae 3

Salmonella can causeSalmonella can cause

1.1. Enteric feverEnteric fever

2.2. GastroenteritisGastroenteritis

3.3. Septicemia with or without focal Septicemia with or without focal suppurationsuppuration

4.4. Carrier stateCarrier state

Salmonella typhi—typhoid feverSalmonella typhi—typhoid fever Eberth-Gaffky bacillus/Eberthella Eberth-Gaffky bacillus/Eberthella

typhityphi

Practically salmonella has been Practically salmonella has been divided intodivided into

1.1. The enteric fever group-The enteric fever group-typhoid,paratyphoid bacillityphoid,paratyphoid bacilli

2.2. The food poisoning groupThe food poisoning group

Gram –ve,rods,motile except S Gram –ve,rods,motile except S gallinarum-pullorum which is always gallinarum-pullorum which is always nonmotilenonmotile

Aerobic and facultative anerobicAerobic and facultative anerobic Grows readily on simple mediaGrows readily on simple media MacConkey and DCC media- colourlessMacConkey and DCC media- colourless Wilson and Blair bismuth sulphite Wilson and Blair bismuth sulphite

medium-jet black coloniesmedium-jet black colonies Selenite F &tetrathionate broth are Selenite F &tetrathionate broth are

commnly employed as enrichment commnly employed as enrichment mediamedia

S typhi- anerogenicS typhi- anerogenic MR+,VP-ve,C+MR+,VP-ve,C+ Typhi- donot grow in Simmon’s citrate Typhi- donot grow in Simmon’s citrate

medium as they need tryptophan as medium as they need tryptophan as the gowth factorthe gowth factor

Antigenic structure-Antigenic structure-

1.1. Flagellar antigen-HFlagellar antigen-H

2.2. Somatic antigen OSomatic antigen O

3.3. Surface antigen-ViSurface antigen-Vi

H antigen- heat labile-strongly H antigen- heat labile-strongly immunogenic,induces antibody immunogenic,induces antibody formation in high titresformation in high titres

O antigen-phospholipid-Protein-O antigen-phospholipid-Protein-Polysacharide complx—also called Boivin Polysacharide complx—also called Boivin antigen---heat stableantigen---heat stable

Vi antigen- analogue to K antigen in the Vi antigen- analogue to K antigen in the coliforms-surface Polysacharide antigen coliforms-surface Polysacharide antigen enveloping the o antigen—heat labile—enveloping the o antigen—heat labile—tend to loss in serial subculturetend to loss in serial subculture

Vi polysacharide acts as a virulence Vi polysacharide acts as a virulence factor by inhibiting phogocytosis-factor by inhibiting phogocytosis-resisting complement activation and resisting complement activation and bacterial lysisbacterial lysis

Poorly immunogenicPoorly immunogenic

Purified Vi vaccinePurified Vi vaccine Total absence of vi antibody in a proven Total absence of vi antibody in a proven

case of typhoid fever indicates poor case of typhoid fever indicates poor PrgnsPrgns

Antibody disappears early in Antibody disappears early in convalescenceconvalescence

Its persistance indicates dvlpmnt of Its persistance indicates dvlpmnt of carrier state.carrier state.

Antigenic variationAntigenic variation

1.1. H-O H-O

2.2. V-W-loss of Vi by sub culture-now V-W-loss of Vi by sub culture-now agglutinable with O antiserum (W agglutinable with O antiserum (W form)form)

3.3. S-R-by loss of O antigen & virulenceS-R-by loss of O antigen & virulence

4.4. O antigen O antigen

H-O variationH-O variation

Associated with loss of flagellaAssociated with loss of flagella Phase Variation-flagellar antigens two Phase Variation-flagellar antigens two

typestypes

1.1. Phase 1 –specific for speciesPhase 1 –specific for species

2.2. Phase 2 –group specificPhase 2 –group specific

3.3. Diphasic-both-Diphasic-both- S.typhi –monophasicS.typhi –monophasic Phase 1 can b converted to 2 by Craigie’s Phase 1 can b converted to 2 by Craigie’s

methodmethod

PathogenicityPathogenicity

Enteric Fever-Enteric Fever-

1.1. Typhoid fever- S. typhiTyphoid fever- S. typhi

2.2. Paratyphoid fever – S.paratyphi Paratyphoid fever – S.paratyphi A,B,CA,B,C

D/s courseD/s course IP-7-14 daysIP-7-14 days Gradual onset-headache,malaise,anorexia-Gradual onset-headache,malaise,anorexia-

caoted tongue-abdominal discomfort-caoted tongue-abdominal discomfort-constipation/diarrhoeaconstipation/diarrhoea

Step ladder pyrexia-typical-Step ladder pyrexia-typical- Hepato splenomegalyHepato splenomegaly Rose spots-in skin which blanch on pressureRose spots-in skin which blanch on pressure Complications-perforation,he,circulatory Complications-perforation,he,circulatory

collpasecollpase Relapse may occur in convalescence-higher Relapse may occur in convalescence-higher

if treated early with chloramphenicolif treated early with chloramphenicol

Paratyphoid is milder form Paratyphoid is milder form Leads to frank septicemia with Leads to frank septicemia with

suppurative complicationssuppurative complications Infection with Alkaligens faecalis- similar Infection with Alkaligens faecalis- similar

c/fc/f Epidemiology-Epidemiology- Carriers-3w-3m-ConvalescentCarriers-3w-3m-Convalescent 3m-1yr-temporary3m-1yr-temporary More than 1yr-c/cMore than 1yr-c/c

Lab d/gLab d/g

Isolation and demonstration of Isolation and demonstration of antibodiesantibodies

,bacilli demonstration,bacilli demonstration Blood culture-diagnostic maximum at Blood culture-diagnostic maximum at

first week,rapidly –ve on treating first week,rapidly –ve on treating with antibioticswith antibiotics

Cultures should be declared –ve only Cultures should be declared –ve only after incubation period of 10 daysafter incubation period of 10 days

May use Casteneda’s method-May use Casteneda’s method-

Feces culture-salmonella are shed in the Feces culture-salmonella are shed in the feces thruout the course of disease,even in feces thruout the course of disease,even in carrierscarriers

Imp, if antibiotics hav started-as they r Imp, if antibiotics hav started-as they r slowly eliminated from gut than from slowly eliminated from gut than from bloodblood

Feces—MacConkey-/DCA/WBFeces—MacConkey-/DCA/WB Clot culture-blood- allowed to clot—serum Clot culture-blood- allowed to clot—serum

is used for widal—clot to bile broth—high is used for widal—clot to bile broth—high rate of isolation as bactericidal action of rate of isolation as bactericidal action of serum is lessserum is less

Urine culture-,Bile culture,rose Urine culture-,Bile culture,rose spots,csf,sputum –less impspots,csf,sputum –less imp

Widal reactionWidal reaction

In H- +ve –loose,cotton woolly In H- +ve –loose,cotton woolly clumpsclumps

O +ve –disc like pattern at the O +ve –disc like pattern at the bottom of the tubebottom of the tube

Result-Result-1.1. Ab appear by end of first week- Ab appear by end of first week-

ifearly –ve—titre inc steadly till 3/4ifearly –ve—titre inc steadly till 3/4thth week and it decline afterweek and it decline after

2.2. Test more samplesTest more samples3.3. 1/100 or more for O & 1/200 or 1/100 or more for O & 1/200 or

more for H is sigfigmore for H is sigfig4.4. Ab-may be due to proir Ab-may be due to proir

d/s,immunisation,carriersd/s,immunisation,carriers

H agglutinins persist longer than OH agglutinins persist longer than O If immunised with TAB, Ab against both If immunised with TAB, Ab against both

,in natural infection only causative org.,in natural infection only causative org. t/ted case –poor Ab titret/ted case –poor Ab titre Other serological methods-ELISA,CIEOther serological methods-ELISA,CIE Staphylococcal co-agglutination test-in Staphylococcal co-agglutination test-in

early phase of d/s-S.aureus-/Cowan 1 early phase of d/s-S.aureus-/Cowan 1 strain-which contains Protein A is strain-which contains Protein A is stabilised by formaldehyde and coated stabilised by formaldehyde and coated with S typhi antibody---1%---with serum with S typhi antibody---1%---with serum –visible agglutination in 2 min–visible agglutination in 2 min

Not paositive after first weekNot paositive after first week

D/g of carriersD/g of carriers

Islation from faeces,bile,urine Islation from faeces,bile,urine culturescultures

Widal is no value in endemic statesWidal is no value in endemic states Demo of Vi agglutinins is impDemo of Vi agglutinins is imp Sewer-swab technique-Gauze pads in Sewer-swab technique-Gauze pads in

sewers and drains -culturedsewers and drains -cultured

PxPx TAB vaccine-with S,typhi,S.paratyphi A & TAB vaccine-with S,typhi,S.paratyphi A &

BB Typhi-1000 millionTyphi-1000 million A & B- 750 million each/ml---killed by A & B- 750 million each/ml---killed by

heating at 50-60C—preserved in phenolheating at 50-60C—preserved in phenol In india- divalant Typhoid-paratyphoid A In india- divalant Typhoid-paratyphoid A

is givenis given Two doses—0.5ml s/c at an intervel of 4-Two doses—0.5ml s/c at an intervel of 4-

6 weeks6 weeks 0.1ml I/D0.1ml I/D Newer vaccinesNewer vaccines

1.1. Typhoral-live oral vaccineTyphoral-live oral vaccine

2.2. Typhin-Vi---injectableTyphin-Vi---injectable

T/tT/t

Chloramphenicol,tetracycline, Chloramphenicol,tetracycline, streptomycinstreptomycin

Ampicilline, Aox,cotrimoxazoleAmpicilline, Aox,cotrimoxazole

Salmonella GastroenteritisSalmonella Gastroenteritis

Enterocolitis/food poisoningEnterocolitis/food poisoning -zoonotic-source of infection –animal -zoonotic-source of infection –animal

productsproducts

Caused by any salmonella except typhiCaused by any salmonella except typhi Short IP-24 hrs-diarrhoea, vomiting, Short IP-24 hrs-diarrhoea, vomiting,

abdominal pain,fever---loose stoolsabdominal pain,fever---loose stools Subsides in 2-4 daysSubsides in 2-4 days T/t –if uncomplicated-symptomatic- T/t –if uncomplicated-symptomatic-

antibiotics not needeantibiotics not neede