Mycobacterium phlei characteristics, morphology, diseases

Alexander Pearson

Mycobacterium phlei It is a fast-growing bacterium that belongs to the group of nontuberculous mycobacteria. As such, it shares many of its characteristics with other mycobacteria..

It was isolated for the first time by the German microbiologist Alfred Möeller in 1898, who initially gave it a provisional name (Bacillus Timothy). It owes its definitive name to the scientists Karl Bernhard Lehmann and Rudolf Otto Neumann.

The Ziehl Neelsen staining method is used to stain acid-fast mycobacteria. Source: This image is a work of the Centers for Disease Control and Prevention, part of the United States Department of Health and Human Services, taken or made during the performance of an employee's official duties. As a work of the United States of the federal government, the image is in the public domain.

In general, this bacterium does not represent a threat to humans, since it is not pathogenic. On rare occasions, strains of this bacterium have been isolated in people with an infection, but those described in the literature are very specific cases..

This is a bacterium that has an excellent response to antibiotic therapy, so it is not fatal. This, of course, when it is detected in time.

Article index

  • 1 Taxonomy
  • 2 Morphology
  • 3 Features
  • 4 Diseases
    • 4.1 -Peritonitis
    • 4.2 -Septic arthritis
  • 5 Treatment
  • 6 References


The taxonomic classification of the Mycobacterium phlei is the next:

Domain: Bacteria

Edge: Actinobacteria

Order: Actinomycetales

Family: Mycobacteriaceae

Gender: Mycobacterium

Species: Mycobacterium phlei.


The Mycobacterium phlei it is a bacterium that is shaped like a thin rod with rounded ends. Bacillus-shaped cells are seen under the microscope, measuring approximately 1 to 2 microns in length..

Its cells are smooth, they do not have any type of extension such as a cilium or flagellum. It also has the characteristic cell wall of bacteria of the genus Mycobacterium. They have a thick layer composed of peptidoglycan and mycolic acid, as well as a middle layer made up of a polysaccharide called arabinogalactan..

Peptidoglycan and arabinogalactan are strongly linked through phosphodiester type bonds. In the cultures, mostly dense colonies with smooth edges and yellowish orange color are observed.

Its genetic material is contained in a single circular chromosome, in which there is an unusual amount of the nitrogenous bases cytosine and guanine, which amounts to approximately 73%.


Growth temperature

This is a bacterium that has a wide-range growth temperature. The bacteria can grow in temperatures ranging from 28 ° C to 52 ° C.

It's Ziehl - Nielsen positive

Thanks to the configuration of its cell wall, this bacterium, like all those belonging to the genus Mycobacterium, cannot be stained through the Gram procedure. This is why other methods such as Ziehl - Nielsen are used..

With this staining method, the bacterial cells take on a reddish coloration that contrasts with the blue background provided by methylene blue..

It's aerobic

The Mycobaterium phlei requires for its development an environment in which there is a wide availability of oxygen, since it needs this vital chemical element to carry out its various metabolic processes.

It's acidic - alcohol resistant

Taking into account the structure of its cell wall, this bacterium is resistant to discoloration by alcohol or acid. This is an indispensable step in traditional staining processes such as the Gram stain. Because of this, these bacteria are stained through other less conventional methods such as Ziehl-Nielsen..

Does not produce spores

Like the rest of the mycobacteria, the Mycobacterium phlei does not generate spores as a survival mechanism in harsh environments.

It is fast growing

The Mycobacterium phlei It is characterized by its high growth rate in culture media. This bacterium has an average growth rate of less than 7 days.

It is catalase positive

This bacterium is characterized by synthesizing the enzyme catalase, through which it is capable of dividing the hydrogen peroxide molecule (HtwoORtwo) in water and oxygen, generating the characteristic bubbles in the process.

It is scotochromogenic

The Mycobacterium phlei belongs to the group of mycobacteria that produce intense yellow carotenoid pigments. Scotochromogens specifically do so in the absence of sunlight.

It is urease positive

This bacterium synthesizes the enzyme urease, thanks to which it can hydrolyze urea into carbon dioxide and ammonia. This is a property that is taken into account to identify bacteria at an experimental level..

Synthesizes the enzyme nitrate reductase

The Mycobacterium phlei synthesizes the enzyme nitrate reductase. This enzyme is responsible for catalyzing the chemical reaction by which nitrate is reduced to nitrite, extracting oxygen from nitrate..


Generally the Mycobacterium phlei it is a non-pathogenic bacteria. However, it has sometimes been associated with several pathologies, among which are: peritonitis in patients with peritoneal dialysis, septic arthritis and infections related to cardiac devices (Endocarditis).


Peritonitis is an inflammation of the membrane that covers the entire inner wall of the abdomen and the organs in it. Peritonitis can have several causes: infection by a viral or bacterial agent, accumulation of fluids, trauma or wounds, among others..

In the case of peritonitis due to Mycobacterium phlei, what happens is that the bacteria enter the abdominal cavity through the peritoneal catheter.


The main symptom that a person with peritonitis experiences is abdominal pain. However, in order to make an accurate diagnosis of peritonitis, it is necessary for the doctor to appreciate the following signs:

  • Abdominal pain
  • Abdominal pain on palpation
  • Abdominal rebound.

Likewise, taking into account that it is a condition that affects the organs of the abdominal cavity, which are part of the digestive system, the following symptoms may also occur:

  • Sickness
  • Vomiting
  • Diarrhea

Similarly, the presence of peritoneal fluid with a cloudy appearance, containing leukocytes, should be appreciated. When making a culture of this liquid, the presence of bacterial cells must be determined, in this case, Mycobacterium phlei.

-Septic arthritis

It consists of the inflammation of a joint due to bacterial or fungal origin.


Among the symptoms of this ailment can be named:

  • Joint pain
  • Joint redness
  • Joint swelling
  • Feverish state

When the doctor examines the patient, they will most likely perform an aspiration of the joint fluid in order to carry out a culture and thus determine the causative agent.


Once an infection by Mycobacterium phlei, the doctor will prescribe an antibiotic-based treatment.

In the culture carried out, information must be obtained about the resistance and susceptibility of the localized bacterial strain. Taking this into account, the doctor will design the treatment to follow.


  1. Septic arthritis. Retrieved from:
  2. Biology of mycobacteria. Obtained from:
  3. Das, S., Petterson, F., Krishna, P., Ramesh, M., Dasgupta, S., Bhattacharya, A. and Kirsebon, L. (2016). The Mycobacterium phlei genome: expectations and surprises. Genome Biol Evol. 8 (4). 975-985
  4. Devarajan, P. (1998). Mycobacterium phlei peritonitis: a rare complication of chronic peritoneal dialysis. Pediatric Nephr 12 (1). 67-68
  5. García, P. and García, L. (2012). Clinical significance and antimicrobial susceptibility of rapidly growing mycobacteria. Obtained from:
  6. Montenegro J. Peritonitis and catheter infections in peritoneal dialysis. In Lorenzo V, López Gómez JM (Eds) Nefrología al Día. Taken from
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