ماهي وتعريفيها Bordetella
الاجابة هي
Bordetella
هي كلمة لاتينية معناها intense cough
Bordetella pertussis contains seven species bordetalla is by far most important species
it the causative agent of whooping cough that effect respiratory tract
morphology
It is gram negative small ovoid coccobacilli
culture
Bordetella pertussis is stric aerobic with optiumum temperature for growth is 35C°
it grow in charcoal agar ,strarch and athers agar buy it do not grow in blood and nutrient agar
bordet gengou agar with 15_20% blood is common media used for primary isolation of bordetella
biochemical reaction
oxidase and catalase positive
becteria do not ferment carbohydrates
do not produce indole
killed by heating to 55C° for
30 minute
humans are only know resvoir of B pertussis
cell wall component and antigenic properties
B .pertussis Possesses lipopolysaccharide
With two distinic types lipid A and lipid B which activate alternative pathway of complement system and realase cytokines
pathogenesis
B. Pertussis colonizes the cilia of respiratory epithelium
ودي نقطه مهمة
ال pertussis غالباً ما بيصيب ال tissue
whooping cough is highly contagious ➡️infection is primary transmitted by inhalation of air borne droplet
ودي اكتر حاجة في ال catarrhal stage
virulence factors
1) filamentous hemagglutinin
Most important virulence factor,mediate attachment of B.pertussis to ciliated cell
2) pertussis toxin
Involved in adhesion of B.pertussis to tracheal epithelium .pertussis toxin consist of two subunit A is enzymaticlly active subunit B is binding subunit
3) invasive adenylate cyclase or hemolysin➡️cause lysis of RBCs
4) tracheal toxin
Killed cilited respiratory cell, stimulate relase of cytokines e.g IL-1 and inhibit ciliary movement
5) lethal toxin
Causes inflammation and lethal necrosis around the site of adherence of bacteria
clinical syndrome
whooping cough( pertussis)
Incubation varies (7_10)days the disease typically has three stages
1)catarrhal stage is the first stage of the whooping cough ➡️the symptom like the symptom of upper respiratory tract ( rhinorrhea , nasal congestion...etc.).
2) paroxymal stage➡️is the second stage classic whooping cough or paroxsmys more common in night
3) convslescen stage is gradul fading stage
lab diagnosis
Specimens
Nasopharyngeal aspirate are specimen of choice
The specimen for culure are collecting by following method
1 pernasl swab
2cough plate method
3 west's postnasl swab
microscopy
By direct fluorscent
culture
Specimen culured on freshly prepared bordet gangau method , or charcoal blood agar
serology
Indirect hemogglutination and ELISA
molecular diagnosis
Polymerase chain reaction
treatment
Erythromycin is the drugs of choice
Also ampicillin is effective
vaccine
There are two types of vaccine
1 whole cell inactivated vaccine
2 acellular vaccine