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BACILLARY DYSENTRY SHIGELLA 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
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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
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
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
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