Mycobacterium hassiacum
Encyclopedia
Mycobacterium hassiacum is a rapid-growing thermophilic mycobacterium
Mycobacterium
Mycobacterium is a genus of Actinobacteria, given its own family, the Mycobacteriaceae. The genus includes pathogens known to cause serious diseases in mammals, including tuberculosis and leprosy...

 that was isolated in human urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...

 in 1997 by researchers at the German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 University of Regensburg
University of Regensburg
The University of Regensburg is a public research university located in the medieval city of Regensburg, Bavaria, a city that is listed as a UNESCO World Heritage Site. The university was founded on July 18, 1962 by the Landtag of Bavaria as the fourth full-fledged university in Bavaria...

. It is not believed to cause disease in humans.

Description

M. hassiacum is a 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 bacteria with partially 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. The scotochromogenic
Scotochromogenic
Scotochromogenic bacteria develop pigment in the dark or in the light. Runyon Group II nontuberculous mycobacteria are examples but the term could apply to many other organisms....

 colonies are yellow, moist, and slimy when grown at 37°C. Distinct and drier colonies form when grown at 60°C.

Physiology

  • Aerobic
    Aerobic organism
    An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment.Faculitative anaerobes grow and survive in an oxygenated environment and so do aerotolerant anaerobes.-Glucose:...

     and thermophilic rapid growth on Löwenstein-Jensen medium at a temperature range between 30°C and 65°C.
  • Growth also occurs on 5% NaCl
    Sodium chloride
    Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...

     and 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...

     without methyl violet
    Methyl violet
    Methyl violet is a family of organic compounds that are mainly used as dyes. Depending on the amount of attached methyl groups, the color of the dye can be altered. Its main use is as a purple dye for textiles and to give deep violet colors in paint and ink...

    .
  • Susceptible to some antibiotics, including streptomycin
    Streptomycin
    Streptomycin is an antibiotic drug, the first of a class of drugs called aminoglycosides to be discovered, and was the first antibiotic remedy for tuberculosis. It is derived from the actinobacterium Streptomyces griseus. Streptomycin is a bactericidal antibiotic. Streptomycin cannot be given...

    , ethambutol
    Ethambutol
    Ethambutol is a bacteriostatic antimycobacterial drug prescribed to treat tuberculosis. It is usually given in combination with other tuberculosis drugs, such as isoniazid, rifampicin and pyrazinamide....

    , cycloserine
    Cycloserine
    Cycloserine is an antibiotic effective against Mycobacterium tuberculosis. For the treatment of tuberculosis, it is classified as a second line drug, i.e...

    , ciprofloxacin
    Ciprofloxacin
    Ciprofloxacin is a synthetic chemotherapeutic antibiotic of the fluoroquinolone drug class.It is a second-generation fluoroquinolone antibacterial. It kills bacteria by interfering with the enzymes that cause DNA to rewind after being copied, which stops synthesis of DNA and of...

     and clarithromycin
    Clarithromycin
    Clarithromycin is a macrolide antibiotic used to treat pharyngitis, tonsillitis, acute maxillary sinusitis, acute bacterial exacerbation of chronic bronchitis, pneumonia , skin and skin structure infections...

    .
  • Resistant to isoniazid
    Isoniazid
    Isoniazid , also known as isonicotinylhydrazine , is an organic compound that is the first-line antituberculosis medication in prevention and treatment. It was first discovered in 1912, and later in 1951 it was found to be effective against tuberculosis by inhibiting its mycolic acid...

    , rifampicin
    Rifampicin
    Rifampicin or rifampin is a bactericidal antibiotic drug of the rifamycin group. It is a semisynthetic compound derived from Amycolatopsis rifamycinica ...

     and prothionamide
    Protionamide
    Protionamide is a drug used in the treatment of tuberculosis.It has also been tested for use in the treatment of leprosy....

    .

Differential characteristics

Like many heat tolerant rapid growers, M. hassiacum has an extended helix 10, due to the insertion of an extra cytosine
Cytosine
Cytosine is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine . It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached . The nucleoside of cytosine is cytidine...

, and a short helix 18. Phylogenetic clustering algorithms place it either with other thermotolerant rapid growers or in a position close to the slowly growing species Mycobacterium xenopi
Mycobacterium xenopi
Mycobacterium xenopi is a slow-growing scotochromogenic species of Mycobacterium. It was first reported by Schwabacher in 1959, having been isolated in lesions found on a Xenopus laevis, but the possibility of human infection was not confirmed until 1965.It has low pathogenicity in humans, and...

.

However, it is easy to distinguish from other mycobacteria by its growth at 65°C and inability to utilise any sugar or citrate
Citrate
A citrate can refer either to the conjugate base of citric acid, , or to the esters of citric acid. An example of the former, a salt is trisodium citrate; an ester is triethyl citrate.-Other citric acid ions:...

. Another key identifying feature is its ability to split benzamide
Benzamide
Benzamide is an off-white solid with the chemical formula of C6H5CONH2. It is a derivative of benzoic acid. It is slightly soluble in water, and soluble in many organic solvents.- External links :* *...

. M. hassiacum can also split urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

, nicotinamide
Nicotinamide
Nicotinamide, also known as niacinamide and nicotinic acid amide, is the amide of nicotinic acid . Nicotinamide is a water-soluble vitamin and is part of the vitamin B group...

, and pyrazinamide
Pyrazinamide
Pyrazinamide is a drug used to treat tuberculosis. The drug is largely bacteriostatic, but can be bacteriocidal on actively replicating tuberculosis bacteria.-Abbreviations:...

.

Pathogenesis

Mycobacterium hassiacum was first isolated from human urine in the German province of Hesse
Hesse
Hesse or Hessia is both a cultural region of Germany and the name of an individual German state.* The cultural region of Hesse includes both the State of Hesse and the area known as Rhenish Hesse in the neighbouring Rhineland-Palatinate state...

, with the host showing no signs of disease. Another isolation of M. hassiacum from urine was also apathogenic. For these reasons, M. hassiacum has been assigned a 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...

1, meaning it is not known to consistently cause disease in healthy adult humans, and is a minimal hazard to laboratory personnel and the environment.

Type strain

Strain 3849 = CCUG 37519 = CIP 105218 = DSM 44199 = JCM 12690. rDNA sequence accession number: U49401.
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