• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.363-373
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• 1986

We developed a giant colony test system with rapidly growing mycobacteria by stab-culture with a loopful inoculum of cells into Middlebrook 7H10 agar medium containing soluble extracts of the fruits of Gardenia jasminoides(7H10-crocin agar medium) and assessed the significance of the giant colony test with 28 strains of 10 clusters of rapidly growing mycobacteria classified by the simple biological 5-test characters. Of the 10 clusters of mycobacteria tested, some of strains which belonged to cluster No. 1a, 5a and 11a did grow as gravis types, whereas most of other clusters gave mitis or intermedius types in their colonial sizes at 12 days culture. By this test, pathogenic strains of M. fortuitum-chelonei complex which belonged to cluster No. 5a, b, 7a and 8a, b could be divided into gravis, intermedius and mitis colony types and the gravis ones were characterized by bluish-white "mushroom-shaped" colonies with central complexes in the texture, whereas the intermedius gave grayish-white "flower-shaped" colonies with radiated folds, but without any central complexes. The mitis colonies were characterized by grayish-white smooth or smooth mucoid colonies and were common among the clusters in their shapes. The colony of M. chelonei was bluish-white mitis type and was characterized by its hilly rhizoid colony. The gravis colony of cluster No. 1a identified as M. phlei was characterized by yellow "round straw- mat-shaped" or "chrysanthemum-shaped" colony with whole complexes in the texture, and the gravis colonies of the cluster No. 11a gave grayish-white "flower-shaped" colonies with central stamens, radiating trough and fine cup-shaped strands in the texture. The four colony types of pathogenic species of M. fortuitum-chelonei complex on 7H10-crocin agar medium were distinctive from those of other clusters of rapidly growing mycobacteria and these results indicated that the giant colony test, in conjunction with the simple 5-test characters, would be of value in the differentiation of M. fortuitum complex from other clusters of rapidly growing mycobacteria.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.2
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• pp.177-184
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• 2019

Mycobacteria grow slowly. Therefore, a solid medium should be used for eight weeks and a liquid medium for six weeks. The purpose of this study was to find the growth factors that can grow Mycobacterium rapidly and to help develop a solid medium for rapid identification. Three types of Mycobacterium growth factors were evaluated with 10 Mycobacteria by adding activated charcoal, defibrinated sheep blood, and L-ascorbic acid to $Difco^{TM}$ Mycobacteria 7H11 agar (Becton, Dickinson and Company, Sparks, MD, USA). The time to detection and the distinguishability of a colony were compared with that of the current method. In the rapidly growing Mycobacterium, the difference in detection time between the new media and conventional media confirmed that the new media was faster. M. kansasii and M. intracelluare grew faster in 7H11 C than in 7H11 medium. MTB grew faster than the other media in 7H11 C. This study confirmed that the two growth factors affect fast-growing Mycobacteria and slow-growing Mycobacteria. 7H11 C showed better distinguishability than the conventional media in all 10 Mycobacterium due to the color contrast. In particular, when the MTB was grown, the size of the colonies was larger than with other media, so visualization was easy.

• Archives of Plastic Surgery
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• v.39 no.1
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• pp.18-24
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• 2012

Background : Infection caused by rapidly growing mycobacteria (RGM) is not uncommon, and the prevalence of RGM infection has been increasing. Clinical diagnosis is difficult because there are no characteristic clinical features. There is also no standard antibiotic regimen for treating RGM infection. A small series of patients with RGM infections was studied to examine their treatments and outcomes. Methods : A total of 5 patients who had developed postoperative infections from January 2009 to December 2010 were retrospectively reviewed. Patients were initially screened using a mycobacteria rapid screening test (polymerase chain reaction [PCR]-reverse blot hybridization assay). To confirm mycobacterial infection, specimens were cultured for nontuberculous mycobacteria and analyzed by 16 S ribosomal RNA and rpoB gene PCR. Results : The patients were treated with intravenous antibiotics during hospitalization, and oral antibiotics were administered after discharge. The mean duration of follow-up was 9 months, and all patients were completely cured of infection with a regimen of a combination of antibiotics plus surgical treatment. Although none of the patients developed recurrence, there were complications at the site of infection, including hypertrophic scarring, pigmentation, and disfigurement. Conclusions : Combination antibiotic therapy plus drainage of surgical abscesses appeared to be effective for the RGM infections seen in our patients. Although neither the exact dosage nor a standardized regimen has been firmly established, we propose that our treatment can provide an option for the management of rapidly growing mycobacterial infection.

• IMMUNE NETWORK
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• v.21 no.6
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• pp.40.1-40.20
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• 2021

Mycobacteroides abscessus (previously Mycobacterium abscessus; Mabc), one of rapidly growing nontuberculous mycobacteria (NTM), is an important pathogen of NTM pulmonary diseases (NTM-PDs) in both immunocompetent and immunocompromised individuals. Mabc infection is chronic and often challenging to treat due to drug resistance, motivating the development of new therapeutics. Despite this, there is a lack of understanding of the relationship between Mabc and the immune system. This review highlights recent progress in the molecular architecture of Mabc and host interactions. We discuss several microbial components that take advantage of host immune defenses, host defense pathways that can overcome Mabc pathogenesis, and how host-pathogen interactions determine the outcomes of Mabc infection. Understanding the molecular mechanisms underlying host-pathogen interactions during Mabc infection will enable the identification of biomarkers and/or drugs to control immune pathogenesis and protect against NTM infection.

• Tuberculosis and Respiratory Diseases
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• v.54 no.3
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• pp.283-294
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• 2003

Introduction : Rapidly growing nontuberculous mycobacteria (RGM) can produce numerous types of manifestations including a pulmonary infection. Managing a pulmonary infection due to RGM is unusually difficult to treat because the organism is invariably resistant to traditional antituberculous drugs and has a varying susceptibility to other antibiotics. The experiences of treatments for a RGM pulmonary infection with various antibiotics are also limited. This study evaluated the clinical manifestations, treatment, and the therapeutic outcomes of a RGM pulmonary infection. Subjects and method : Fifty-four cases with RGM from respiratory specimens were identified between November of 1996 and September of 2002 in the Asan medical center. The medical records and radiographic findings in 20 patients who fulfilled the diagnostic criteria of nontuberculous mycobacteria (NTM) pulmonary disease by ATS guidelines. The clinical, laboratory, and radiological parameters between subgroups. Results : Of the 20 patients, 15 were female. The mean age was 57.7 yrs (${\pm}7.5$), and all of the patients had a history of pulmonary tuberculosis. Most (90%) had an underlying lung disease. The majority of the isolates (80%) were M. abscessus. Chest radiography showed bilateral involvement in 80% of the patients. Bronchiectasis and multiple nodules were the main findings. Cavitation was present in 35% of the patients. Even though 70 % of the patients received antituberculous drugs prior to the correct diagnosis, all of the patients eventually received antibiotics. A mean of 3.5 antibiotics were given for an average of 439 days(${\pm}168$). After completing treatment, nine patients showed improvement after a mean 591(${\pm}311$) days of treatment, whereas the antibiotic treatment was unsuccessful in 2 patients. Conclusion : Many patients with a RGM pulmonary infection show an atypical pattern of radiological findings (bronchiectasis and multiple centrilobular nodules). It is very important to differentiate between M. tuberculosis and NTM and to identify the causative organisms among the NTM because a misdiagnosis can lead to an inappropriate and prolonged treatment. Combined antibiotic treatment yielded promising results, and is recommended for treating patients with a RGM pulmonary infection.

• Annals of Geriatric Medicine and Research
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• v.22 no.4
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• pp.204-207
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• 2018

Mycobacterium abscessus comprises rapidly growing mycobacteria, and the clinical manifestations of M. abscessus skin infection include papule, nodule, ulcer, scar and mixed form. The cutaneous infections have been reported due to minor trauma, cosmetic therapy, acupuncture and disseminated infection. A 75-year-old man presented with pruritic diffuse various sized erythematous papuloplaques and pustules on the neck and chest for 2 months. The cutaneous lesions were spread around the wound of the shaving on the neck. The histopathologic findings were consistent with abscess showing infiltrations of neutrophils and lymphocytes in the dermis and negative findings were observed on immunohistochemical stain including acid-fast bacilli stain. One month later, mycobacterial culture result showed positive findings, and the pathogen was identified by reversetranscriptase polymerase chain reaction with hybridization. The patient was treated with combination of clarithromycin and ethambutol for 5 months and there is no evidence of recurrence after 6 months of follow-up. Herein, we report a case of M. abscessus cutaneous infection through minor trauma caused by shaving in the elderly.

• Tuberculosis and Respiratory Diseases
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• v.54 no.1
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• pp.45-56
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• 2003

Background : Mycobacterium abscessus is the most common respiratory pathogen in rapidly growing mycobacteria and is resistant to all of the first-line antituberculosis drugs. This report describes the clinical and radiographic characteristics in patients with pulmonary disease caused by M. abscessus. Materials and Methods : Twelve patients with pulmonary disease caused by M. abscessus who fulfilled the 1997 American Thoracic Society diagnostic criteria for a nontuberculous mycobacterial pulmonary infection were observed over a five-and-a-half year period. The clinical characteristics and chest radiographic findings were analyzed, retrospectively. Results : The patients were predominantly female(11/12, 92%) and nonsmokers(12/12, 100%). Coughing (10/12, 83%), sputum(10/12, 83%) and hemoptysis(10/12, 83%) were the common symptoms and they had prolonged periods from the onset of symptoms to the diagnosis of their disease(median 6.5 years). Eleven (92%) patients had a previous history of being treated for pulmonary tuberculosis. The sputum specimens were acid-fast bacilli smear-positive in all patients. All patients were administered antituberculosis drugs. Six (50%) patients were treated with second-line antituberculosis drugs on account of persistent smear-positive sputum specimens. The chest radiographs showed that reticulonodular opacities(11/12, 92%) were the most common pattern of abnormality, followed by cavitary lesions(5/12, 42%). The computed tomography findings suggested bronchiolitis from the centrilobular nodules with a tree-in-bud appearances(9/10, 90%) and bronchiectasis (9/10, 90%) were the most common, followed by well-defined nodules smaller than 10-mm in diameter(7/10, 70%). Conclusions : M. abscessus pulmonary disease should be recognized as a cause of chronic mycobacterial lung disease, and respiratory isolates should be assessed carefully.

• Annals of Clinical Microbiology
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• v.17 no.1
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• pp.23-27
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• 2014

Rapidly growing mycobacteria are ubiquitous in the environment and are increasingly being recognized as opportunistic pathogens. Recently, a new species, Mycobacteium conceptionense, has been validated from the Mycobacterium fortuitum third biovariant complex by molecular analysis. However, there are few reports, and postsurgical wound infection by this species is rare. We report a case of postsurgical wound infection caused by M. conceptionense in an immunocompetent patient that was identified by a sequencing analysis of 16S rRNA, hps65, and rpoB genes.