Is mycobacteria fast growing?
Rapidly growing mycobacteria (RGM) are non-tuberculous mycobacteria (NTM) that can form mature colonies on agar plates within 7 days [1].
A characteristic feature of mycobacteria is their slow growth rate, which in addition strongly varies in different species of the genus. All highly pathogenic species such as M. tuberculosis and M.
Abstract. The rapidly growing mycobacteria (RGM) differ from slow-growing mycobacteria such as Mycobacterium tuberculosis by virtue of their more rapid growth in culture media and their in vitro resistance to standard antituberculosis drugs. The RGM can produce numerous infections including chronic lung disease.
Introduction. Mycobacterium marinum is a pigmented slow-growing non-tuberculous mycobacterium associated with skin and soft tissue infections.
Fifty percent of species in the M. tuberculosis complex were detected within 14 days, and 50% were detected within 21 days.
Mycobacterial cultures grow MAC in about 1-4 weeks, depending on the culture technique and bacterial burden.
Among the slowly growing mycobacteria (SGM), the most clinically relevant species are members of M. avium complex (MAC), M. haemophilum, M.
M. intracellulare, M. avium, and MAC [8,9,14] typically take 2–3 weeks to grow in the traditional solid media phase, whereas broth media can produce more rapid results [1]. Both methods use media optimized for mycobacterial growth, most commonly 7H9 broth and 7H10 agar plates [1,8,9,14].
Slow-growing bacteria species are perhaps best known for Mycobacterium tuberculosis, a human pathogen with a generation time being no less than 16 h.
Mycobacterium tuberculosis grows within the phagocytic vacuoles of macrophages, where it encounters a moderately acidic and possibly nutrient-restricted environment. Other mycobacterial species encounter acidic conditions in soil and aquatic environments.
What is special about mycobacteria?
The hallmark of mycobacteria is their unique abundance in lipid, constituting up to 40% of the dry weight of the tubercle bacillus3,4. The mycobacterial cell wall contains up to 60% of lipids, as compared with some 20% for the lipid-rich cell walls of Gram-negative microorganisms4.
Clinical and radiographic manifestations
The symptoms are often nonspecific such as chronic cough, increased sputum production, dyspnea, low-grade fever, malaise and weight loss, and overlapping clinical characteristics with pulmonary TB11,12. Radiological imaging is important when NTM lung disease is suspected.
Mycobacteria have an outer membrane. They do not have capsules, and most do not form endospores. The distinguishing characteristic of all Mycobacterium species is that the cell wall is thicker than in many other bacteria, which is hydrophobic, waxy, and rich in mycolic acids/mycolates.
Different bacteria have different ways of responding to staining agents, and this allows scientists to differentiate between them. Because of its thick cell wall with the mycolic acids, mycobacterium tuberculosis does not respond very well to staining agents. In fact, it is very difficult to stain any mycobacterium.
Recent evaluations of the MacConkey agar test for differentiation of rapidly growing mycobacteria have revealed that certain strains of Mycobacterium fortuitum and M. chelonei that were expected to grow on MacConkey agar failed to do so.
Drug-susceptible TB is treated with isoniazid (INH), rifampicin (RIF), pyrazinamide and ethambutol for two months followed by four months of INH and RIF, while treatment of multi-drug-resistant (MDR) TB can require up to two years of chemotherapy with possible damaging side effects. Drugs that kill M.
Mycobacteria can grow in fluid environments, they can form aggregates, form biofilms and they are invasive i.e. they can grow and multiply within cells such as macrophages. Inside the macrophage they reside within a membrane-bound cytoplasmic vacuole referred to as the Mycobacterium phagosome.
A complete cure can be expected with some NTM strains but not with others. Reinfection is common. To avoid becoming infected again, you may need to make some lifestyle changes.
Nontuberculous mycobacteria are tiny germs found in soil, water, and on both tame and wild animals. They're harmless to most people. But sometimes when these bacteria get into your body, they can cause a serious lung disease. NTM infections are becoming more common, especially among people ages 65 and older.
In some people, MAC lung disease can cause respiratory failure and death, but this generally happens over a long period of time. Approximately 1 in 4 people with weakened immune systems who develop the cavitary type of MAC lung disease die within five years of the initial MAC lung disease diagnosis.
Can you survive MAC lung disease?
It is important to note that while MAC Lung Disease can be life-threatening for immune-compromised individuals, it can also be treatable and curable for many others! MAC Lung Disease is classified as curable if the sputum cultures show no evidence of infection for 12 months (Cleveland Clinic).
If untreated, there is a higher chance of developing bronchitis and pneumonia. The most severe type, Fibrocavitary Disease, occurs when the infection has created a cavity or “hole(s)” in the lung tissue. These patients need more immediate treatment to get the infection under control.
intracellulare are killed in <5 seconds (3) when exposed to 70oC; thus, all NTM species would likely be killed a few seconds after water reached the boiling point.
Key Facts. MAC infection is a serious condition that can cause damage to the lungs. MAC infection is not contagious. Common signs and symptoms of MAC lung disease include fatigue, chronic cough, shortness of breath, night sweats, coughing up blood and weight loss.
The most common species of NTM is called MAC, or Mycobacterium avium complex. Sometimes, doctors will call an NTM infection "MAC" or "MAC lung disease" because it's the species most often identified in patients. Eight out of 10 NTM infections in the US are caused by MAC.
The current TB drugs isoniazid (INH) and ethionamide (ETH) kill mycobacteria via direct conversion to free radicals that may contribute to the formation of MDR M. tuberculosis strains.
The NTM infection in the lungs causes scarring, fibrosis and the formation of cavities or pits in the lung tissue. This damage can lead to respiratory failure. This form is most commonly found in people with a smoking history who also have existing lung disease such as COPD or bronchiectasis.
Humans are the only reservoir for Mycobacterium tuberculosis. The organism is an acid-fast, aerobic bacillus with a high cell wall content of high-molecular-weight lipids. Visible growth takes 3 to 8 weeks on solid media.
Traditionally, mycobacteria are identified by phenotypic methods, based on culture, such as morphological characteristics, growth rates, preferred growth temperature, pigmentation and on a series of biochemical tests.
An AFB culture can positively confirm a diagnosis of TB or other infection. But it takes 6–8 weeks to grow enough bacteria to detect an infection.
Which atypical mycobacteria is rapid grower?
Rapidly growing mycobacteria (RGM) have a propensity to produce skin and soft-tissue infections. Among the RGM, the three most clinically relevant species are M. abscessus, M. chelonae, and M.
Abstract. In summary, rapidly growing mycobacteria, M. fortuitum and M. chelonei, are pathogens of increasing importance which are often hospital-acquired and can infect patients with iatrogenic immunosuppression.
The Greek prefix myco- means 'fungus', alluding to the way mycobacteria have been observed to grow in a mold-like fashion on the surface of cultures.
- They cannot be stained by the Gram stain because of their high lipid content.
- Acid fast staining is used to stain mycobacteria. Bacteria are treated with a red dye (fuchsin) and steamed. ...
- EPIDEMIOLOGY.
- THE DISEASE TUBERCULOSIS (Pathogenesis, Clinical Findings, and Host Response)
The hallmark of mycobacteria is their unique abundance in lipid, constituting up to 40% of the dry weight of the tubercle bacillus3,4. The mycobacterial cell wall contains up to 60% of lipids, as compared with some 20% for the lipid-rich cell walls of Gram-negative microorganisms4.
Mycobacteria can grow in fluid environments, they can form aggregates, form biofilms and they are invasive i.e. they can grow and multiply within cells such as macrophages. Inside the macrophage they reside within a membrane-bound cytoplasmic vacuole referred to as the Mycobacterium phagosome.
Treatment options include clarithromycin or azithromycin, with the addition of amikacin, cefoxitin, or imipenem for serious and complicated infections.
Rapid-growing mycobacteria are a distinctive subset of the "atypical" or non-tuberculous mycobacteria. Widely distributed in the environment, they appear to be generally acquired from soil or water, but they are unfortunately common as agents of nosocomial infection.
Removal of foreign bodies, such as breast implants and percutaneous catheters, is important and essential to achieving cure, as M fortuitum forms biofilm. Surgical debridement of cutaneous or subcutaneous lesions is often required to achieve cure.
Mycobacterium fortuitum is one of the many species of nontuberculosis mycobacteria (NTM) that are commonly found in the environment.
What are the symptoms of Mycobacterium?
- Cough.
- Weight loss.
- Coughing up blood or mucus.
- Weakness or fatigue.
- Fever and chills.
- Night sweats.
- Lack of appetite and weight loss.
Nontuberculous mycobacteria are a type of bacteria found in water and soil. These bacteria are typically harmless. However, when they enter the body, they can cause skin lesions, soft tissue infections, and serious lung problems.
Mycobacterium abscessus [mī–kō–bak–tair–ee–yum ab–ses–sus] (also called M. abscessus) is a bacterium distantly related to the ones that cause tuberculosis and Hansen's Disease (Leprosy). It is part of a group of environmental mycobacteria and is found in water, soil, and dust.
Mycobacteria are Gram-positive, catalase positive, non-motile, non-spore forming rod-shaped bacteria (0.2–0.6 μm wide and 1.0–10 μm long). The colony morphology of mycobacteria varies with some species growing as rough or smooth colonies. Colony colour ranges from white to orange or pink (Iivanainen, 1999).
Drug-susceptible TB is treated with isoniazid (INH), rifampicin (RIF), pyrazinamide and ethambutol for two months followed by four months of INH and RIF, while treatment of multi-drug-resistant (MDR) TB can require up to two years of chemotherapy with possible damaging side effects.
Mycobacterial cells are irregular rods 0.3–0.5 μm in diameter and of variable length (Wayne and Kubica, 1986).
