Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 17, Number 3—March 2011
Letter

Mycobacterium novocastrense–associated Pulmonary and Wound Infections

Cite This Article

To the Editor: Although the clinical role of nontuberculous mycobacteria has long been appreciated (1), the high endemicity of tuberculosis (TB) in developing countries has overshadowed the emergence of these organisms. They are simply dismissed as being contaminants or are misidentified as Mycobacterium tuberculosis (2).

No report on M. novocastrense has been published since its original description in 1997 (3), except for a study in France by N’Guessan et al. (4). That study initiated speculation about the possible role of this bacterium in the etiology of human infection. We report isolation of M. novocastrense in 2 independent clinical cases—1 from tissue biopsy specimen of an apparently healthy adult, the other from bronchoalveolar lavage of an HIV-infected patient—that will cast light on the clinical relevance of this rare species.

Case-patient 1, a 60-year-old woman, was referred to a hospital because of high fever, productive cough, thoracic pain, and noticeable weight loss. After her husband’s AIDS-related death in a state prison, HIV infection had been diagnosed in this case-patient. At admission, laboratory testing showed negative tuberculin skin test result, lymphopenia, an elevated C-reactive protein level of 76 mg/L, an erythrocyte sedimentation rate of 73 mm/h, a viral load of 500 copies/mL, and negative blood culture for bacterial growth. Her outpatient records indicated that she empirically was given numerous courses of antimicrobial drugs because of a provisional diagnosis of bacterial pneumonia, but her condition did not improve. Subsequent hospital referral was prompted by worsening of her symptoms. With a diagnosis of suspected TB, bronchoalveolar lavage fluid was collected. Direct microscopic examination of the specimen showed acid-fast bacilli with subsequent formation of typical colonies of a relatively rapidly growing photochromogenic Mycobacterium spp. on Löwenstein-Jensen (LJ) medium. The patient was treated with amikacin, and her condition markedly improved.

Case-patient 2, a 23-year-old woman, sought care for a 6-month history of soft tissue swelling in her left leg resulting from an accidental injury in a paddy field. The lesion had not been treated and subsequently increased in size. The large nodule self-ruptured and excreted yellow-pale pus. She was prescribed minocycline by her general practitioner, but the lesion did not resolve. When the patient arrived at the hospital, her clinical and laboratory assessments were normal. She had negative test results for HIV, hepatitis C, and hepatitis B infections. Erythrocyte sedimentation rate was 255 mm/h. Culture of a biopsy specimen from the cutaneous lesion on ordinary culture media was negative, although microscopic observation of the drainage fluid showed acid-fast bacilli. This finding was confirmed by a positive culture on LJ medium. A repeat specimen resulted in isolation of the same organism in pure culture. The patient was given amikacin and fully recovered in <1 month.

The isolates, i.e., HNTM1 and HNTM10, were subjected to preliminary identification and susceptibility to common antimycobacterial agents for rapidly growing mycobacteria according to standard procedures (5,6). The isolates were then subjected to molecular identification, which included PCR amplification of a genus-specific region of the 65-kDa heat shock protein (hsp) gene (7) and the direct sequence analysis of 16S rDNA, hsp65, and rpoB genes as described (3,8,9). GenBank accession numbers for the gene sequences of HNTM1 as a representative isolate determined in this study are HM807280–HM807282.

The isolates we observed by acid-fast staining of the specimens and recovered on LJ medium were a yellow pigmented photochromogenic species that grew rapidly at 25°C, 37°C, and 42°C. They grew on MacConkey agar without crystal violet and LJ medium containing 5% NaCl; were positive for semiquantitative catalase, arylsulfatase activity in 14 days, and nitrate reduction; and were negative for urease activity, niacin production, tellurite and Tween hydrolysis, heat-stable (68°C) catalase, and iron uptake. They were susceptible to amikacin, clarithromycin, doxycycline, sulfamethoxazole, streptomycin, imipenem, ciprofloxacin, isoniazid, and ethambutol but resistant to rifampin.

The PCR amplification of a 228-bp genus-specific fragment of the hsp65 gene reliably confirmed that the isolates belonged to the genus Mycobacterium. The almost complete 16S rDNA gene sequence (1,476 bp) and partial sequences of hsp65 and rpoB genes of the isolates showed the highest similarity of 99.86%, 99.45%, and 99.7% with that of M. novocastrense reference strain. These values correspond to 2-nt differences for each gene.

Our report of 2 independent clinical cases might support evidence the clinical relevance of M. novocastrense. Our findings show that M. novocastrense, however rare its incidence might be, can cause infection in healthy and immunocompromised patients. However, because of the complexity of identifying nontuberculous mycobacteria, emphasis should be placed on the quality of regional laboratories for TB in developing countries to differentiate isolates to the species level.

Top

Acknowledgment

This study was supported by the office of vice-chancellor for research, Isfahan University of Medical Sciences.

Top

Hasan ShojaeiComments to Author , Abodolrazagh Hashemi, Parvin Heidarieh, and Abass Daei Naser
Author affiliations: Author affiliations: Isfahan University of Medical Sciences, Isfahan, Iran (H. Shojaei, A. Hashemi, A.D. Naser); Tehran University of Medical Sciences, Tehran, Iran (P. Heidarieh)

Top

References

  1. Falkinham  JO III. Epidemiology of infection by nontuberculous mycobacteria. Clin Microbiol Rev. 1996;9:177215.PubMedGoogle Scholar
  2. Jarzembowski  JA, Young  MB. Nontuberculous mycobacterial infections. Arch Pathol Lab Med. 2008;132:133341.PubMedGoogle Scholar
  3. Shojaei  H, Magee  JG, Freeman  R, Yates  M, Horadagoda  NU, Goodfellow  M. Mycobacterium novocastrense sp. nov., a rapidly growing photochromogenic Mycobacterium. Int J Syst Bacteriol. 1997;47:12057. DOIPubMedGoogle Scholar
  4. N’Guessan  K, Vincent  V, Nahoua  G, Kamate  M, Dosso  M. Mycobacterium novocastrense isolated from sputum: contamination or pulmonary infection? [in French]. Med Mal Infect. 2006;36:180.PubMedGoogle Scholar
  5. Kent  PT, Kubica  GP. Public health mycobacteriology: a guide for the level III laboratory. Atlanta: Centers for Disease Control, US Department of Health and Human Services; 1985.
  6. National Committee for Clinical Laboratory Standards. Susceptibility testing of mycobacteria, nocardiae, and other aerobic actinomycetes: approved standard. Wayne (PA): The Committee; 2003.
  7. Khan  IU, Yadav  JS. Development of a single-tube, cell lysis-based, genus-specific PCR method for rapid identification of mycobacteria: optimization of cell lysis, PCR primers and conditions, and restriction pattern analysis. J Clin Microbiol. 2004;42:4537. DOIPubMedGoogle Scholar
  8. Kim  H, Kim  SH, Shim  TS, Kim  MN, Bai  GH, Park  YG, Differentiation of Mycobacterium species by analysis of the heat-shock protein 65 gene (hsp65). Int J Syst Evol Microbiol. 2005;55:164956. DOIPubMedGoogle Scholar
  9. Adékambi  T, Colson  P, Drancourt  M. rpoB-based identification of nonpigmented and late-pigmenting rapidly growing mycobacteria. J Clin Microbiol. 2003;41:5699708. DOIPubMedGoogle Scholar

Top

Cite This Article

DOI: 10.3201/eid1703.101400

Related Links

Top

Table of Contents – Volume 17, Number 3—March 2011

EID Search Options
presentation_01 Advanced Article Search – Search articles by author and/or keyword.
presentation_01 Articles by Country Search – Search articles by the topic country.
presentation_01 Article Type Search – Search articles by article type and issue.

Top

Comments

Please use the form below to submit correspondence to the authors or contact them at the following address:

Hasan Shojaei, Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

Send To

10000 character(s) remaining.

Top

Page created: July 25, 2011
Page updated: July 25, 2011
Page reviewed: July 25, 2011
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
file_external