6,295views
00:00 / 00:00
Summer Micro
Bacterial structure and functions
Staphylococcus epidermidis
Staphylococcus aureus
Staphylococcus saprophyticus
Streptococcus viridans
Streptococcus pneumoniae
Streptococcus pyogenes (Group A Strep)
Streptococcus agalactiae (Group B Strep)
Enterococcus
Clostridium perfringens
Clostridium botulinum (Botulism)
Clostridium difficile (Pseudomembranous colitis)
Clostridium tetani (Tetanus)
Bacillus cereus (Food poisoning)
Listeria monocytogenes
Corynebacterium diphtheriae (Diphtheria)
Bacillus anthracis (Anthrax)
Nocardia
Actinomyces israelii
Escherichia coli
Salmonella (non-typhoidal)
Salmonella typhi (typhoid fever)
Pseudomonas aeruginosa
Enterobacter
Klebsiella pneumoniae
Shigella
Proteus mirabilis
Yersinia enterocolitica
Legionella pneumophila (Legionnaires disease and Pontiac fever)
Serratia marcescens
Bacteroides fragilis
Yersinia pestis (Plague)
Vibrio cholerae (Cholera)
Helicobacter pylori
Campylobacter jejuni
Neisseria meningitidis
Neisseria gonorrhoeae
Moraxella catarrhalis
Francisella tularensis (Tularemia)
Bordetella pertussis (Pertussis/Whooping cough)
Brucella
Haemophilus influenzae
Haemophilus ducreyi (Chancroid)
Pasteurella multocida
Mycobacterium tuberculosis (Tuberculosis)
Mycobacterium leprae
Mycobacterium avium complex (NORD)
Mycoplasma pneumoniae
Chlamydia pneumoniae
Chlamydia trachomatis
Borrelia burgdorferi (Lyme disease)
Borrelia species (Relapsing fever)
Leptospira
Treponema pallidum (Syphilis)
Rickettsia rickettsii (Rocky Mountain spotted fever) and other Rickettsia species
Coxiella burnetii (Q fever)
Ehrlichia and Anaplasma
Gardnerella vaginalis (Bacterial vaginosis)
Viral structure and functions
Varicella zoster virus
Cytomegalovirus
Epstein-Barr virus (Infectious mononucleosis)
Human herpesvirus 8 (Kaposi sarcoma)
Herpes simplex virus
Human herpesvirus 6 (Roseola)
Adenovirus
Parvovirus B19
Human papillomavirus
Poxvirus (Smallpox and Molluscum contagiosum)
BK virus (Hemorrhagic cystitis)
JC virus (Progressive multifocal leukoencephalopathy)
Poliovirus
Coxsackievirus
Rhinovirus
Hepatitis A and Hepatitis E virus
Hepatitis D virus
Influenza virus
Mumps virus
Measles virus
Respiratory syncytial virus
Human parainfluenza viruses
Dengue virus
Yellow fever virus
Zika virus
Hepatitis C virus
West Nile virus
Norovirus
Rotavirus
Coronaviruses
HIV (AIDS)
Human T-lymphotropic virus
Ebola virus
Rabies virus
Rubella virus
Eastern and Western equine encephalitis virus
Lymphocytic choriomeningitis virus
Hantavirus
Prions (Spongiform encephalopathy)
Francisella tularensis (Tularemia)
0 / 7 complete
of complete
2022
2021
2020
2019
2018
2017
2016
animal transmission p. 147
Gram-negative algorithm p. 139
Alexandru Duhaniuc, MD
Francisella tularensis is a Gram-negative coccobacillus, which means that shape-wise, it’s somewhere between a spherical coccus and a rod-like bacillus.
In humans, it causes a zoonotic infection called tularemia, also called rabbit fever.
This bacteria is also considered a category A bioterrorism agent which means it is of highest concern for bioterrorism use, because of its low infectious dose and high associated mortality.
Now, Francisella tularensis has a thin peptidoglycan layer, so it doesn’t retain the crystal violet dye during Gram staining.
Instead, like any other Gram-negative bacteria, it stains pink with safranin dye.
Alright, now Francisella tularensis is non-motile, non-spore forming, facultative intracellular which means it can survive both outside and inside the cell and aerobic which means it can survive only in the presence of oxygen.
Also, it’s oxidase and urease negative which means it doesn’t produce these enzymes.
Finally, Francisella tularensis is a fastidious bacteria which requires enriched medium for growth.
And Francisella tularensis really loves cysteine, so it only grows in about 47 to 72 hours on cysteine-enriched mediums like cysteine enriched chocolate agar, BCYE and CHAB.
Cysteine enriched chocolate agar, named so for its color, actually contains cysteine and lysed red blood cells - so no chocolate products were harmed in the making of this medium.
BCYE stands for buffered charcoal yeast extract, so it contains activated charcoal, yeast extract, and L-cysteine.
On these two mediums, Francisella tularensis forms round, grey-white colonies.
Finally, CHAB is a glucose cysteine agar that contains thiamine and blood, and on CHAB, Francisella tularensis forms greenish-white, round, smooth, mucoid colonies.
Now, Francisella tularensis has a number of virulence factors, that are like assault weaponry that help it attack and destroy the host cells, and evade the immune system.
So first, Francisella tularensis is encapsulated, meaning it’s covered by a polysaccharide layer called a capsule.
Francisella tularensis is a gram-negative, facultative intracellular coccobacillus, known to cause a zoonotic infection known as tularemia. Tularemia can be transmitted to humans by ticks, deer flies, rabbits, and deer flies.
Depending on the transmission route, tularemia has several forms, including ulceroglandular, oculoglandular, and pneumonic. The ulceroglandular form occurs when the bacteria enter through a break in the skin. The ulcer at the site of infection becomes swollen and painful, and may discharge pus. Glands near the ulcer may also become enlarged. Next, the oculoglandular form occurs when the bacteria are spread to the eyes. Symptoms include redness, swelling, and pain in the eyes, photophobia, as well as swollen lymph nodes., Finally, the pneumonic form occurs when the bacteria are inhaled and resulting in pneumonia. Symptoms include fever, chest pain, and coughing up blood.
Copyright © 2023 Elsevier, except certain content provided by third parties
Cookies are used by this site.
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.