BACILLARY DYSENTRYSHIGELLA SPECIES

Dr.Indumathi

KLEBSIELLA

• GRAM NEGATIVE • NON MOTILE• CAPSULATED • LACTOSE FERMENTING(MUCOID)• IMViC --++

• FORMS GUT AND RESPIRATORY FLORA IN 5% NORMAL INDIVIDUALS

CLASSIFICATION

• 3 SPECIES”• K.pneumonia ; K.rhinoscleromatis and

K.ozanae• PATHOGENIC LESIONS:• HAEMORRHAGIC NECROTIZING

CONSOLIDATION OF LUNG (1%) : • UTI• BACTEREMIA & OTHER FOCAL INFECTION• NOSOCOMIAL INFECTION

PNEUMONIA

• FRIEDLANDER’S PNEUMONIA : CAP• MIDDLE AGED AND OLD ALCOHOLICS• SEVERE RAPID ONSET• OFTEN FATAL• HIGH FEVER, CHILLS, CURRENT JELLY

SPUTUM• ABSCESS, CAVITATION, EMPYEMA • LOBAR PNEUMONIA WITH DESTRUCTIVE

CHANGES : USUALLY UPPER LOBE

KLEBSIELLA PNEUMONIA

RHINOSCLEROMA

• K.RHINOSCLEROMATIS• AFRICA, ASIA, LATIN AMERICA• DESTRUCTIVE GRANULOMA OF NOSE AND

PHARYNX • PURULENT NASAL DISCHARGE• CRUSTING LESIONS WITH NODULE• RESPIRATORY OBSTRUCTION• DIAGNOSIS BY HPE AND POSITIVE BLOOD

CULTURE

RHINOSCLEROMA

OZENA

• K.OZAENAE

• FETID PROGRESSIVE ATROPHY OF NASAL MUCOSA

• NASAL CONGESTION

• PRIMARY ATROPHIC RHINITIS IN ELDERLY

• NASAL BAD SMELL

• HEADACHE

HISTORICAL REVIEW

• TERM DYSENTRY: BY HIPPOCRATES• FREQUENT PASSAGE OF STOOL WITH

BLOOD AND MUCOUS • STRAINING AND PAINFUL DEFECATION• 19TH CENTRURY : 2 FORMS OF DYSENTRY

ACCURATELY SEPARATED• EPIDEMICS DYSENTRY IN MILITARY CAMPS,

ASYLUMS, JAILS BY SHIGELLA• SPORADIC CASES OF DYSENTRY BY

AMEOBA

SHIGELLA

• GRAM NEGATIVE SHORT RODS• NON MOTILE• ANAEROGENIC• NON CAPSULATED• GIT PATHOGEN• NON LACTOSE FERMENTER• COMPLEX ANTIGENIC STRUCTURE• NAMED AFTER SHIGA 1896

CLASSIFICATION

• 4 SPECIES/SUBGROUPS BASED ON BIOCHEMICAL AND SEROLOGICAL CHARACTERS

• SHIGELLA DYSENTERIAE : 12 Serotypes

• SHIGELLA FLEXNERI : 6 serotypes

• SHIGELLA BOYDII : 18

• SHIGELLA SONNEI : 17 Colicine types

EPIDEMIOLOGY : BACILLARY DYSENTRY

• PREVALENT IN TROPICS/WORLD WIDE• SUMMER MONTHS• POOR SANITATION• OVERCROWDING /POVERTY• EPIDEMICS • MAN IS THE ONLY HOST :

CASE/CARRIER :RESERVOIR • SHORT INCUBATION (48 HRS)

EPIDEMIOLOGY

• CYCLIC PATTERN OF DISEASE

• EPIDEMICS DUE TO ONE SPECIES LASTING FOR 20-30YRS.

• E.G. 20TH CENTURY : S.DYSENTERIAE

IN EUROPE

• 1926-38 S.FLEXNERI

• CURRENTLY S.SONNEI : IN INDUSTRIALISED COUNTRIES

EPIDEMIOLOGYINDIA

• ENDEMIC /HIGHLY COMMUNICABLE• FOUND IN ALL AGE GROUPS• ALL SPECIES : S.FLEXNERI

PREDOMINANT(50-85%)• S.DYSENTERIAE(8-25%)• S.SONNEI (2-24%)• S.BOYDII(0-8%)• EPIDEMICS AND SERVERAL OUTBREAKS

FROM 1974 : KERALA AND WEST BENGAL• MULTIPLE DRUG RESISTANT STRAINS :

CAUSING EPIDEMICS

PATHOGENESIS

• SOURCE : MAN: CASE OR CARRIER• MODE OF SPREAD: CONTAMINATED

FINGERS, FOOD, FLIES, FOMITES• PERSON TO PERSON TRANSMISSION• INFECTIVE DOSE: 10-100 VIABLE BACILLI • HIGHEST CONCENTRATION IN STOOL

DURING EARLY/ACUTE INFECTION 103 TO 109 VIABLE BACILLI PER GRAM OF STOOL

• POST CONVALESCENT SHEDDING : LOW COUNTS 102 TO 103

PATHOGENESIS

• VIRULENCE FACTORS

• 1.INVASIVENESS : ASSOCIATED WITH BACTERIAL PROTEIN CODED IN PLASMIDS OR CHROMOSOME.

• 2. TOXIN PRODUCTION : EXOTOXIN THAT IS ENTERO,NEURO AND CYTOTOXIC : SHIGA TOXIN

PATHOGENESIS•

INGESTED BACILLI• ↓

• TRANSIENTLY MULTIPLY IN SMALL INTESTINE CONCENTRATION OF 107 TO109 PER ML

• ↓• ENTER THE DISTAL COLON (MULTIPLY) INVADE THE MUCOSAL CELLS, • ↓• MULTIPLY AND SPREAD TO ADJECENT CELLS(INTRACELLULAR

SPREAD)• ↓• ACUTE INFLAMMATION AND MICROABSCESS/CAP THROMOBOSIS• SUPERFICIAL ULCERATION (SERPIGINOUS)• ↓• ENDOTOXIN PRODUCTION TO PRODUCE BOWEL IRRITATION AND

DIARRHOEA WITH BLOOD/MUCUS AND TOXEMIA

PATHOGENESIS

• NO BLOOD STREAM INVASION• BACTERIA RAPIDLY PHAGOCYTOSED BY

MACROPHAGES• ENTEROTOXIN : LOCAL MUCOSAL DESTRUCTION• CLINICALLY : DYSENTRY LASTS FOR 1 TO 7 DAYS

SELF LIMITING• HIGH MORTALITY IN MALNOURISHED• COMPLICATIONS :HEMOLYTIC UREMIC

SYNDROME : SHIGA TOXIN : RENAL FAILURE, TOXIC NEURITIS, ARTHRITIS

• RARELY : IKARI SYNDROME : MASSIVE INFECTION AND EARLY DEATH IN CHILDREN

CLINICAL FEATURES

• FEVER : HIGH GRADE • TOXEMIA• ABDOMINAL CRAMPS• VOLUMINOUS WATERY DIARRHOEA• FOLLOWED BY SMALL VOLUME FREQUENT

PASSAGE OF BLOODY STOOLS. (OVER 10/DAY)• ABDOMINAL TENDERNESS• COMPLICATIONS: FEBRILE SEIZURES,

SEPSIS, PNEUMONIA

LAB DIAGNOSIS

SPECIMEN COLLECTION :

STOOL CONTAINING MUCOUS/BLOOD

RECTAL SWAB

RECTAL CATHETERIZATION

RECOVERY IS BEST IN THE ACUTE STAGE WHERE BACILLI ARE SHED IN LARGE NUMBERS

LAB DIAGNOSIS

• TRANSPORT MEDIUM

• BGS/CARY BLAIR

• ENRICHMENT : SELENITE F

METHODS OF DIAGNOSIS

DIRECT MICROSCOPY

CULTURE

SLIDE AGGLUTINATION TEST

LAB DIAGNOSIS

• MACROSCOPY

• BRIGHT RED STOOL

• ADHERENT TO CONTAINER

• ALKALINE

• ODOURLESS

• NO FAECAL MATTER

• SMALL QUANTITY :

LAB DIAGNOSIS

• MICROSCOPY• NUMEROUS PUS CELLS : STAINED FEACAL

SMEARS WITH METHYLENE BLUE (SINGLE MOST IMPORTANT LAB TEST OTHER THAN STOOL CULTURE)

• NUMEROUS DISCRETE/ROULEUX RBCS• NO BACTERIA SEEN• PLENTY OF MACROPHAGES• GHOST CELLS : CELLS WITH NO NUCLEUS

AND ONLY CYTOPLASMIC OUTLINE : PRESENT

LAB DIAGNOSIS

• CULTURE : MEDIA USED :• FLUID : SELENITE F ENRICHMENT• SOLID: MAC CONKEY’S• DCA• SSA• STEPS : DIRECT PLATING + ENRICHMENT

CULTURE• GROWTH FROM FLUID MEDIUM

SUBCULTURED ONTO MA

LAB DIAGNOSIS

• COLONIES ON MA/DCA : NLF PALE AND TRANSLUCENT

• COLONIES PICKED UP FOR THE FOLLOWING TESTS:

• HANGING DROP : NON MOTILE• GRAM’S :GNB• BIOCHEMICAL TESTS : IMVIC ++--

ANEROGENIC FERMENTERS• SLIDE AGGLUTINATION WITH SPECIFIC HTS

BIOCHEMICAL TESTS

SPECIES GLUCOSE LACTOSE MANNITOL INDOLE

S.DYS ACID - - V

S.FLEX ACID - + V

S.BOYDI ACID - + V

S.SONEI ACID - + -

TREATMENT AND PREVENTION

• ANTIBIOTICS TO BE GIVEN BECAUSE• 1. PERSON TO PERSON TRANSMISSION : INFECTED

PERSON IS THE RESERVOIR IN ORDER TO PREVENT THE CHAIN OF TRANSMISSION

• GOOD SANITATION/SAFE DISPOSAL OF SEWAGE• SAFE WATER SUPPLY• SHIGELLA VACCINE (ORAL: STREP DEP

MUTANT:LIVE ATTEN)4 DOSES ; PROTECTION 6 MONTHS. EXP IN HYPERENDEMIC AREAS.

SALMONELLA GASTROENTERITIS

• * FOOD POISONING• ZOONOTIC INFECTION• ANIMAL OR ANIMALPRODUCTS: MEAT

PRODUCTS, EGGS, CREAM, MILK (FOOD CONTAMINATION WITH RAT OR LIZARD DROPPINGS)

• S.TYPHIMURIUM/S.ENTERITIDIS, S.NEWPORT

• IP 24 HOURS DIARRHOEA, VOMITTING, PAIN ABDOMEN, FEVER