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
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