Bacillary Dysentery (shigellosis) Dept. Of Infectious Disease Huang Fen.

Bacillary Dysentery (shigellosis) Dept. Of Infectious Disease Huang Fen

Transcript of Bacillary Dysentery (shigellosis) Dept. Of Infectious Disease Huang Fen.

Bacillary Dysentery (shigellosis)

Dept. Of Infectious Disease

Huang Fen


Acute infectious disease of intestine caused by dysentery bacilli(genus shigella)

Place of lesion: sigmoid & rectum

Pathological feature:

diffuse fibrious exudative



Clinical manifestation:

fever, abdominal pain, diarrhea,

tenesmus , stool mixed with

mucus blood, & pus.

even companied with shock,



Causative organism:

dysentery bacilli, genus shigella,

gram-stained negative,

non-motile short rod,

Groups: 4 serogroups &47 serotypes


S. dysenteriae: the most severe

S. flexneri: the epidemic group

and easily turn to chronic

S. boydii: tropical and subon

S. sonnei: the most mild


Pathogenicity: - virulence endotoxin - exotoxin - invasiveness (attach-penetrate-multiply)

Resistance: Strong, 1-2week in fruits,vegetable and dirty soil, heat for 60 30 min℃


Source of infection: patients and carriers

Route of transmission:

fecal-oral route

Suceptibility of population:

immunity after infection is short

and unsteady, no cross-immune


Epidemic features:

season: summer & fall

Flexneri, Soneii, dysentery

age: younger children

Pathogenesis number of bacteria toxicity invasiveness





normal intestinal florasIg A

prevent attaching

penetrate mucus

multiply in epithelia cell & proper lamina


endogenous pyrogen fever

inflammationvessel contraction

superficial mucosal necrosis and ulcer

diarrhea mixed with blood & pus, abdominal pain


strong - allergy to endotoxin

demethyl-adrenaline DIC

micro-circulatory failure

shock, cerebral edema

cerebral hernia

Pathology site of lesion:

entire large bowel-

sigmoid colon & rectum


acute: diffuse fibrinous

exudative inflammation,

Pathology hyperemia, edema, leukocyte infiltration, superficial necrosis, ulcer.

chronic: edema, polypoid hyperplasia,

toxic: colon: hyperemia, edema, micro- capillary was invaded

Clinical manifestation

Incubation period: 1-2 day, (hours to 7 days)

Acute dysenterycommon type

mild type

toxic type

Clinical manifestationcommon type: (typical type)

acute onset , shiver, high feverabdominal pain(tenderness)diarrhea: stool mixed with

mucus, blood & pustenesmus, 1 week

Clinical manifestation

mild type: ( atypical type)caused by S. sonnei

low fever or no fever

abdominal pain is mild

stool mixed with mucus, without

blood & pus

diagnosis by isolation of bacteria


Clinical manifestation

toxic type:

age: 2 to 7 yrs.abrupt onset, high fever, T 40oCdysphoria, lethargy, convulsion

repeatedly,coma.circulatory & respiratory collapsediarrhea mild or absent at beginning

Clinical manifestation

shock form: septic shock brain form:


repeatedly,coma, brain hernia. respiratory failure

mixed form

Clinical manifestation

chronic dysentery: > 2 months

chronic delayed type:chronic obscure type

acute attack type

Clinical manifestation

chronic delayed type: long-time and repeated abdominal

pain, diarrhea, stool mixed with

mucus, blood & pus.

with fatigue, anemia, malnutrition.

Clinical manifestation

chronic obscure type: acute history in 1 year, no symptoms,

stool culture positive or sigmoidscopy

acute attack type:

same as common acute dysentery

Laboratory Findings

Blood picture: WBC count increase, (10~20×109/L) neutrophils increase

Stool examination:gross examination: stool mixed with

mucus, blood & pus.

Laboratory Findings

direct microscopic examination: WBC, RBC, pus cells

bacteria culture:PCR:DNA

Sigmoidoscopy: chronic patients shallow ulcer scar polyp

Differential diagnosis

acute dysenteryamebic dysentery

Entamoeba histolytica

stool: reddish brown, like jam

flask-shaped ulcer,

amebic trophozoite

Differential diagnosis

enteritis caused by E. Coli,

salmonella, virus.

intussusception: jam-like stools,

abdominal mass

absence of fever

Differential diagnosis

chronic dysenteryrectal & colonic carcinoma:

no cure for long-term, drop of weight of body

non-specific ulcer colitis: no cure for long-term, culture of stool is negative,

Differential diagnosis

sigmoidoscopy: hemorrhage,

ulcer, lead pipe.

chronic schistosomiasis Japonica contact with the contaminated water

hepatomegaly and splenomegaly

founding the ovum of schistosomiasis


Differential diagnosis

toxic dysentery

encephalitis B: highfever,convulsion,coma.• <24h• circulatory failure• stool examination• CSF• meningeal irritation• Specific IgM


Common dysentery

Toxic dysentery general treatment

pathogenic treatment :


Ampicillin given by IV


symptomatic treatment:• control of high fever,convulsion:

subhibernation • treatment of shock: same as ECM• treatment of cerebral edema:

20% mannitol


chronic dysenterygeneral therapy:


diet, nurishing

avoid overwork


etiologic therapy:

sensitive antibiotics

used in turn or combined use

according to results of culture


expectant treatment.



Control the source of infection:

until culture negative

Interrupting the route of transmission:

Protecting the susceptible population:

F2a-secretary IgA

protect 80%-6-12mon