Also called Malignant pustule; most common form; initiated by entrance of bacilli through abrasions of the skin; pustule appears on hands or forearms which develops into vesicles of filled with dark fluid; rupture of vesicles reveal BLACK ESCHAR (no pus) formation
Also called Inhalational Anthrax or Woolsorter's disease or Ragpicker's disease; most severe form initiated by inhalation of spores during shearing, sorting, and handling of animal hair
Also called violent enteritis; the rarest form; initiated by ingestion of bacilli or spore from infected meat resulting to invasion and ulceration of gastrointestinal mucosa
1. BAP – non-hemolytic, opaque in "Medusa or Lion-head" appearance due to masses of long, hair-like curls
2. PEA – recommended for fecal specimen
3. NA – colonies have "Cut-glass appearance" on transmitted light
4. Egg Yolk agar (EYA) – to determine lecithinase production of B. anthracis
5. Gelatin Medium – organisms liquify gelatin resembling an "Inverted Fir tree or Inverted Pine Tree" appearance
6. PLET (Polymyxin Lysozyme EDTA Thallous acetate) – selective medium for the isolation of B. anthracis in contaminated specimen; this culture medium maybe added with bicarbonate agar to induce B. anthracis capsule formation
Reflects the susceptibility of the strain to penicillin; organism is streaked on solid media with 10-unit penicillin disk placed over the streak and incubated for 3-6 hours at 37°C; the cells become large and spherical occurring in chains as seen on the surface of the agar, resembling a string of pearls (+)
Short incubation type (Emetic type) – associated with FRIED RICE due to heat-stable enterotoxin; patient vomits with no fever
Long incubation type (Diarrheal type) – associated with meat or vegetable dishes; associated with health-labile enterotoxin; watery stool without fever
Bacillus cereus is one of the many species that produce the enzyme lecithinase, demonstrated by a zone of opacity (whitish color on the agar) extending away from the bacterial growth
These Chinese character arrangements are caused by snapping during binary fission
4 major biotypes: C. diphtheriae var gravis (produces serious disease), C. diphtheriae var intermedius (mild disease), C. diphtheriae var belfanti (mild disease), C. diphtheriae var mitis (cause very minimal disease)
Caused by powerful exotoxin produced by the strains of C. diphtheriae infected with specific beta bacteriophage carrying the TOX gene responsible for toxin production (heat labile polypeptide) which destroys the epithelial cells lining the respiratory tract and numerous membrane by arresting CHON synthesis of the cells
The organism exhibits Lysogenicity
Pseudomembrane formation – the most pathognomonic sign of diphtheria; grayish white pseudo-membrane formation usually occurs in the upper respiratory tract; initial lesions usually occurs on tonsils and oropharynx which then spreads to the nasopharynx and trachea
Clinical manifestations: low grade fever, malaise, and mild sore throat; edematous and tender cervical lymph nodes (bull neck appearance); mechanical obstruction of the airway may ensue due to the membrane accompanying edema of the larynx and trachea; complications may involve the cardiovascular and nervous system; hemorrhaging of the nasal mucosa (endothelial damage)
Laboratory identification of Corynebacterium diphtheriae
1. Specimen: NPS and Throat swab
2. Stained smear – to demonstrate the characteristic morphology and use of special stains to demonstrate the metachromatic granules (LAMB, Neisser's, Ljubinsky and Gohar)
3. Culture: BAP, Tinsdale Tellurite Medium, Pai's coagulated medium, CTA, LSS – enhances the pigmentation and granule production
1. Stained smear – to demonstrate the characteristic morphology and use of special stains to demonstrate the metachromatic granules (LAMB, Neisser's, Ljubinsky and Gohar)
2. Culture: BAP, Tinsdale Tellurite Medium
3. Pai's coagulated medium
4. CTA
5. LSS – enhances the pigmentation and granule production