Bordetella & Brucella 10.pptx

Bacteriology Abdulmajid Almahdi  Bordetella Bordetella Bordet ella Scientist genus Small g-ve cocco baclli. Strict aerobic. Encapsulated. The most important species: Borde...

Bacteriology Abdulmajid Almahdi  Bordetella Bordetella Bordet ella Scientist genus Small g-ve cocco baclli. Strict aerobic. Encapsulated. The most important species: Bordetella pertussis Virulence factors 1. Attachment factors: Filamentous heamagglutinin (FHA). is the major attachment factor produced by virulent Bordetella spp. (attachment, adherence) Pertussis toxin (PTx) Cell-bound form. (attachment, adherence) Free form. (toxin) 2. Factors mediating tissue damage “toxin” 1. Pertussis toxin (PTx) Causes striking lymphocytosis. Increase sensitivity to histamine. 2. Adenylate cyclase toxin.( increase fluid secretion----- edema). 3. Tracheal cytotoxin. Inhibit cilary movement. Kills ciliated epithelial cells in the respiratory tract. 4. Endotoxin.  Bordetella pertussis Causing whooping cough. Morphology: as in genus Culture characteristics: Enriched medium (blood). Bordet-Gengou agar.(blood agar + growth factor of Bordetella pertussis). Charcoal blood agar. Slow grower 6-7days at 37C. Colonies characterised by mercury droplets appearance.  Bordetella pertussis Incubation period: 1-2 wks. Acute respiratory diseases. ( children) Transmitted via inhalation of droplets. Organism is non invasive. It has many stages: 1. Catarrhal stage Duration: 1-2 wks. It is attachment and adhesion stage so the organism needs virulence factors; FHA, PTx. Clinical manifestation: runny nose, fever, malaise. (resemble common cold) Organism in large number. Antibiotic effective stages 2. Paroxysmal stage: (tissue damage stage). Duration 3 wks. PTx “free form”, Adenylate cyclase toxin, tracheal cytotoxin , endotoxin. Characterized by episodes of coughing with a distinctive “whooping” sound when breathing in (inspiration), ending with vomiting. Organism (rarely isolated). Antibiotics “no effect”. Stages & Diagnosis 3. Convalescent stage: Begins approximately 4 weeks after onset of the disease. Episodes of coughing become less frequent and not as severe. Slow recovery begins during this phase of the disease. Duration 3wks. No organism. Diagnosis: *can be diagnosed clinically. 1. specimen: Nasopharyngeal secretion swab. Aspiration of Nasopharyngeal secretion. Cough plate. Diagnosis 2. Direct detection Direct fluorescent assay (DFA). Polymerase chain reaction “PCR”. 3. Culture Bordet-Gengou agar. Charcoal agar..Takes 6-7 days at 37 C 4. Identification Oxidase +ve, catalase +ve.Morphology: mercury droplets appearance on plate Treatment & prevention. Treatment: Erythromycin Prevention: Whooping cough vaccine..killed whole cell vaccine, part of DPT vaccine.1 Acellular vaccine ( genetically inactivated PTx). ( DTAP) for.2.children 5-6 yrs then booster dose after 10 yrs Chemoprophylaxis: Erythromycin  Brucella Named after David Bruce (1855–1931). Characteristics features: Short g-ve (coccobacilli). Aerobic, non motile, non capsulated. Facultative intracellular pathogen. Zoonotic disease. Primary infection in animal.  Brucella Members of the genus: Brucella abortus.--- (abortion in cattle) Brucella melitensis ---- (goats, sheep, and camels). Brucella suis.----- (pigs) Morphology: as in genus Culture: Enriched medium. “blood”. If B. abortus---- give 10% CO2. (Capnophiles)  Biochemical properties Oxidase +ve, catalase +ve. Reduce nitrate to nitrite. *Moderately sensitive to heat and acidity. Antigen structure: A antigen------B. abortus. M antigen ----- B. melitensis.  Brucellosis Undulant fever or malt fever. Temp. raises gradually till peak then decreases gradually. Zoonotic. Mode of transmission: Ingestion of animal secretion. Direct contact with infected animal. Inhalation of animal secretion. Pathogensis Endotoxin is the major virulence factor. Clinical manifestation: Fever, chill, sweating, headache, malaise, weakness, undulant fever, body ache. Enlarged ( lymph nodes, liver, spleen). Osteomyelitis Meningitis. Recovery (weeks – month)----- chronic. Lab. Diagnosis: 1. Specimen: blood, bone morrow (invasive). 2. Other sample ( acc. to site of infection).  Lab. Diagnosis 3. Direct detection& cultivation.(dangerous) 4. Serology: Standard tube agglutination test. ELISA Brucellin Test. Rarely use Treatment and prevention Combination therapy for long time Doxycycline & Rifampicin Prevention: Control of infected animal.1 Live attenuated vaccine ----- cattle..pasteurization of milk.2 Thank you