Mycobacterium fortuitum is a nontuberculous mycobacterium.

Background

Mycobacterium fortuitum is a fast-growing species that can cause infections. The term "fast growing" is a reference to a growth rate of 3 or 4 days, when compared to other Mycobacteria that may take weeks to grow out on laboratory media. Pulmonary infections of M. fortuitum are uncommon, but mycobacterium fortuitum can cause local skin disease, osteomyelitis (inflammation of the bone), joint infections and infections of the eye after trauma. Mycobacterium fortuitum has a worldwide distribution and can be found in natural and processed water, sewage, and dirt.

Bacteria classified as Mycobacteria, include the causative agent for tuberculosis and leprosy. Mycobacteria are sometimes referred to as “acid-fast bacteria,” a term referencing their response to a laboratory staining technique. This simply means that when microscopic slides of these bacteria are rinsed with an acidic solution, they retain a red dye. Mycobacterium fortuitum is one of the many species of nontuberculosis mycobacteria (NTM) that are commonly found in the environment. These are not involved in tuberculosis. This does not mean, however, that they will not cause an infection in the right circumstances.

M. fortuitum infection can be a nosocomial (hospital acquired) disease. Surgical sites may become infected after the wound is exposed directly or indirectly to contaminated tap water. Other possible sources of M. fortuitum infection include implanted devices such as catheters, injection site abscesses, and contaminated endoscopes.

Description

Gram-positive

Gram-positive

Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...

, nonmotile and acid-fast

Acid-fast

Acid-fastness is a physical property of certain bacteria, specifically their resistance to decolorization by acids during staining procedures.Acid-fast organisms are difficult to characterize using standard microbiological techniques Acid-fastness is a physical property of certain bacteria,...

 rods (1-3 µm x 0.2-0.4 µm). Sometimes long rods with occasional beaded or swollen cells having non-acid-fast ovoid bodies at one end.

Colony characteristics

• Smooth hemispheric colonies
  Colony (biology)
  In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...
  
  , usually off-white or cream colored. May be butyrous, waxy, multilobate and even rosette clustered (dilute inocula).
• On Malachite green
  Malachite green
  Malachite green is an organic compound that is used as a dyestuff and has emerged as a controversial agent in aquaculture. Malachite green is traditionally used as a dye for materials such as silk, leather, and paper...
  
   containing media, such as Löwenstein-Jensen media, colonies can absorb the green dye.

Physiology

• Rapid growth on Löwenstein-Jensen media within 2–4 days.
• No growth at 45°C, but grows on MacConkey agar
  MacConkey agar
  MacConkey agar is a culture medium designed to grow Gram-negative bacteria and stain them for lactose fermentation.-Contents:It contains bile salts MacConkey agar is a culture medium designed to grow Gram-negative bacteria and stain them for lactose fermentation.-Contents:It contains bile salts...
  
  .

Differential characteristics

• Differentiation from M. fortuitum subsp. acetamidolyticum by its ability to utilise L-glutamate and its inability to utilise acetamide
  Acetamide
  Acetamide is an organic compound with the formula CH3CONH2. It is the simplest amide derived from acetic acid. It finds some use as a plasticizer and as an industrial solvent...
  
   as simultaneous nitrogen
  Nitrogen
  Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
  
   and carbon
  Carbon
  Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
  
   source. Both subspecies share an identical 5'-16S rDNA sequence. However, the ITS sequences are different.

Pathogenesis

• Different types of sporadic infections: pulmonary disease, local abscesses.
• Postoperative sternal wound infections, endocarditis
  Endocarditis
  Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves . Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or even on intracardiac devices...
  
  , meningitis
  Meningitis
  Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
  
  , and osteomyelitis
  Osteomyelitis
  Osteomyelitis simply means an infection of the bone or bone marrow...
  
  .
• Has produced postoperative infections after breast augmentation surgery.
• Biosafety level
  Biosafety level
  A biosafety level is the level of the biocontainment precautions required to isolate dangerous biological agents in an enclosed facility. The levels of containment range from the lowest biosafety level 1 to the highest at level 4 . In the United States, the Centers for Disease Control and...
  
   2

Treatment

The 2007 guideline “Official American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA) statement: diagnosis, treatment, and prevention of non-tuberculosis mycobacterial diseases”, notes that M. fortuitum isolates are usually susceptible to multiple oral antimicrobial agents, including the macrolides and quinolones, doxycycline and minocycline, and sulfonamides. Isolates of this mycobacterium are susceptible to the beta-lactam antibiotics, belonging to the carbopenam subgroup, such as Imipenem. Imipenem is a broad spectrum antibiotic produced by the bacteria Streptomyces cattleya. Ondansetron HCL (Zofran) is an antiemetic often given to offset the nausea and vomiting that are a common side effect of Imipenem. Severe infections require IV treatment combined with oral antibiotics for a prolonged period, up to several months. The guideline recommends “for serious skin, bone, and soft tissue M fortuitum disease, a minimum of 4 months of therapy with at least two agents with in vitro activity against the clinical isolate is necessary to provide a high likelihood of cure. Surgery is generally indicated with extensive disease, abscess formation, or where drug therapy is difficult.”

Type Strain

• Found world-wide in soil
  Soil
  Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
  
  , dust
  Dust
  Dust consists of particles in the atmosphere that arise from various sources such as soil dust lifted up by wind , volcanic eruptions, and pollution...
  
  , river
  River
  A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
  
  s, lakes and tap water
  Tap water
  Tap water is a principal component of "indoor plumbing", which became available in urban areas of the developed world during the last quarter of the 19th century, and common during the mid-20th century...
  
  .
• First isolated from a 25-year old patient (syringe abscess) in Rio de Janeiro
  Rio de Janeiro
  Rio de Janeiro , commonly referred to simply as Rio, is the capital city of the State of Rio de Janeiro, the second largest city of Brazil, and the third largest metropolitan area and agglomeration in South America, boasting approximately 6.3 million people within the city proper, making it the 6th...
  
  .
• Also isolated from lymph glands of cattle
  Cattle
  Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
  
   and systemic or nodular infection of frog
  Frog
  Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
  
  s.

Strain ATCC

American Type Culture Collection

The American Type Culture Collection is a private, not-for-profit biological resource center whose mission focuses on the acquisition, authentication, production, preservation, development and distribution of standard reference microorganisms, cell lines and other materials for research in the...

 6841 = CCUG 20994 = CIP 104534 = DSM 46621 = IFO (now NBRC) 13159 = JCM 6387 = NCTC 10394.

Subsequently, this species has been divided into subspecies
M. fortuitum subsp. acetamidolyticum