MICROBIOLOGY-NON BRANCHING, CATALASE POSITIVE, GRAM-POSITIVE BACILLI (BACILLUS AND SIMILAR ORGANISMS) Flashcards
o Aerobic
o Facultative or strictly anaerobic
o Gram-positive
o Spore-forming rods
Bacillus
What are the characteristics of Bacillus anthracis?
- Aerobic
- Gram-positive box
car-like rods - Nonmotile
- Spore-forming
(endospores) - Nonhemolytic ”comet
tail or Medusa head”
or ground glass
colonies on 5% sheep
blood agar - Rarely found
HABITAT ni Bacillus anthracis
In soil, contracted by various herbivores
MODE OF TRANSMISSION ni Bacillus anthracis
- Direct contact: animal tissue or
products such as wool or hair - Traumatic or insect bites: organisms
or spores - Injection: contaminated drugs
- Ingestion: contaminated meat
- Inhalation: spores; during exposure
to animal products (wool sorter’s
disease) - Person-to-person transmission (rare)
Virulence Factor ni Bacillus Anthracis
Lethal toxin and Edema Toxin
It is primarily responsible for death.
lethal toxin (LT)
It facilitates the transport of other proteins into the cell.
protective antigen (PA)
It is responsible for edema.
edema toxin (ET)
Name the functional enzymes involved in virulence factors.
Lethal factor (LF) and Edema factor (EF).
What type of anthrax accounts for most human infections?
Cutaneous anthrax.
How is cutaneous anthrax contracted?
Through contact with infected animal products and inoculation of endospores through a break in the skin.
What are the symptoms of cutaneous anthrax?
Papule ring of vesicles leading to ulceration (eschar).
How is cutaneous anthrax treated?
it is effectively treated with antibiotics.
How is gastrointestinal anthrax contracted?
By ingestion of endospores.
What are the two forms of gastrointestinal anthrax?
Oral or oropharyngeal (buccal cavity or tongue, tonsils, or pharyngeal mucosa) and gastrointestinal (mucosa of the terminal ileum).
What was inhalation anthrax previously referred to as?
Pulmonary anthrax.
How is inhalation anthrax contracted?
By inhalation of endospores.
What are the initial symptoms of inhalation anthrax?
Flu-like symptoms: fever, chills, fatigue, nonproductive cough, nausea, and vomiting.
What are the advanced symptoms of inhalation anthrax?
Respiratory distress, edema, cyanosis, shock, and death.
What are the common name for inhalation anthrax?
Woolsorters’ disease and ragpickers’ disease.
What are the chest X-ray findings in inhalation anthrax?
Pleural effusion, infiltrates, and mediastinal widening.
How is injectional anthrax contracted?
Through contaminated drugs of abuse (heroin).
What are the symptoms of injectional anthrax?
Severe soft tissue infection and dissemination leading to septic shock.
How should specimens be collected for laboratory diagnosis of anthrax?
Specimens should be collected in leak-proof containers and placed in a secondary container.
Where should samples be taken from for cutaneous anthrax diagnosis?
Samples should be taken from underneath the eschar.
What type of testing is used for cutaneous anthrax?
Histochemical testing with a punch biopsy in 10% formalin.
What specimens are collected for inhalation anthrax diagnosis?
Blood cultures, pleural fluid, and serum for serology.
What tissues are biopsied for inhalation anthrax?
Bronchial tissue or pleural tissue.
What specimens are collected for gastrointestinal anthrax diagnosis?
Blood cultures, ascites fluid, material from any lesions, and serum for serology.
What are the direct detection methods for anthrax?
Detection of large, gram-positive rods in singles, pairs, or serpentine chains.
What is the width of vegetative cells of B. anthracis?
The vegetative cell width is usually greater than 1µm, and the endospores do not cause swelling of the cell.
It is used for the selection and isolation of B. anthracis from contaminated species.
Polymyxin-lysozyme-EDTA-thallous acetate (PLET)
What media are used for the cultivation of B. anthracis?
5% sheep blood agar, chocolate agar, routine blood culture media, and nutrient broths.
Medium-large, gray, flat irregular with swirling projections (Medusa head or comet tail) or ground glass appearance, nonhemolytic.
B. anthracis
it induces B. anthracis capsule formation, resulting in large and mucoid colonies.
bicarbonate agar
purpose of heat shock treatment in the cultivation of B. anthracis?
-is used for the growth and enhancement of endospores from clinical specimens
-typically at 62-65°C for 15-20 minutes.
What serodiagnostic methods are used to detect antibodies to B. anthracis?
Indirect hemagglutination and ELISA.
What antigens or proteins are typically detected in serodiagnosis of B. anthracis?
PA antigen, toxin protein, LF, and EF.
What is the treatment for severe anthrax?
IV ciprofloxacin (7-10 days) plus one aminoglycoside or two additional drugs.
What genetic analysis methods are used for B. anthracis?
Multilocus sequence typing (MLST) and multiple-locus variable-number tandem-repeat analysis.
What is the treatment for cutaneous or uncomplicated anthrax?
Oral ciprofloxacin or doxycycline for 7-10 days.
What are the prevention methods for anthrax?
-Cell-free inactivated vaccine
-chemoprophylaxis with ciprofloxacin or doxycycline after aerosol exposure to B. anthracis.
IDENTIFY
is crystal-forming and cold-tolerant.
Bacillus thuringiensis
is known for being heat-tolerant?
Bacillus weihenstephanensis
is known for being a probiotic.
Bacillus cytotoxicus
Name three other species in the Bacillus cereus group
Bacillus toyonensis,Bacillus mycoides and B. pseudomycoides
HABITAT sa Bacillus cereus group
- Soil
- Widely distributed in
nature - Vegetative cells and
spores ubiquitous in
nature; may
transiently colonize
skin or GIT or
respiratory tracts
MODE OF TRANSMISSION sa
(Bacillus cereus group)
- Trauma
- Associated with immunocompromised patients
- Predominantly ingestion
of food (rice) contaminated with B. cereus-type species or toxins formed by this organism
IDENTIFY THE TOXINS
Diarrheal symptoms.
Hemolysin BL (HBL)
How do Hemolysin BL (HBL) and Nonhemolytic enterotoxin (Nhe) act?
They act synergistically.
Which toxin is responsible for the major symptoms in diarrheal presentation?
Nonhemolytic enterotoxin (Nhe).
What is another name for Cytotoxin K?
Hemolysin IV.
Which toxin is a heat-stable, proteolysis, and acid-resistant toxin.
Cereulide
What form does Cereulide cause?
Emetic form.
What systemic conditions can Bacillus species cause
Bacteremia, endocarditis, and septicemia.
What are some health-care associated infections caused by Bacillus species?
Contaminated gowns, gloves, linens, dressings, and medical devices (ventilators, catheters, and bronchoscopy equipment).
What toxin does B. thuringiensis harbor?
Cereulide toxin.
What are the two types of symptoms of food poisoning caused by Bacillus species?
Diarrhea and abdominal pain within 8-16 hours, and nausea and vomiting (emetic food poisoning) within 1-5 hours.
What is the commercial use of B. thuringiensis toxins?
They are used for the control of insects that cause agricultural damage (moths, beetles, flies, and parasitic worms).
Large gram-positive rods in singles, pairs, or serpentine chains, and endospores that may appear as gram variable.
Bacillus cereus group
What media are used for the cultivation of Bacillus species?
-5% sheep blood agar,
-chocolate agar,
-routine blood culture media,
-nutrient broths,
- specific Bacillus cereus media like MEYP, PEMBA, and BCM.
What is the purpose of heat shock treatment in Bacillus species?
To kill vegetative cells and retain spores, effective at 70°C for 30 minutes or 80°C for 10 minutes.
What serodiagnostic methods are used for detecting B. cereus toxin in food and feces?
Oxoid BCET-RPLA and TECRA VIA.
