Nocardia Identification at the Genus Level

To the Editor:

Takashima et al recently published their report on purulent pericarditis accompanying pericardial abscess induced by Nocardia in an immunocompromised patient.¹ The genus Nocardia that causes nocardiosis in human and animals is gram-positive and partially acid-fast. This bacterium was first reported by Edmond Nocard in 1888. Accurate identification at the genus level includes: colonial morphology, various stainings such as Gram stain, acid-fast and partially acid-fast, investigation of aerial hyphae with stereomicroscope, growth in lysozyme broth and molecular methods such as PCR-sequencing and PCR-RFLP. Furthermore, treatment of nocardial infections depends on the species.^2–7

We request the authors attend to the following questions.

1. Please explain the Nocardia isolation method, which was not mentioned in the report.

2. Other genera in the Actinomycetes family, such as non-Mycobacterium tuberculosis, Gordonia etc., are similar to Nocardia in some phenotypic characteristics. Please explain how Nocardia was identified at the genus level.

• Mehdi Fatahi-Bafghi, PhD
• Department of Microbiology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

References

• 1.    Takashima  A,  Yagi  S,  Yamaguchi  K,  Watanabe  S,  Yamamoto  N,  Ito  H, et al. Purulent pericarditis accompanying pericardial abscess induced by Nocardia in an immunocompromised patient. Circ J 2016; 80: 2409–2411.
• 2.    Goodfellow  M,  Lind  A,  Mordarska  H,  Pattyn  S,  Tsukamura  M. A co-operative numerical analysis of cultures considered to belong to the ‘rhodochrous’ taxon. Microbiology 1974; 85: 291–302.
• 3.    Goodfellow  M. Characterisation of Mycobacterium, Nocardia, Corynebacterium and related taxa. Ann Soc Belg Med Trop 1973; 53: 287–298.
• 4.    Brown-Elliott  BA,  Brown  JM,  Conville  PS,  Wallace  RJ. Clinical and laboratory features of the Nocardia spp. based on current molecular taxonomy. Clin Microbiol Rev 2006; 19: 259–282.
• 5.    Bafghi  MF,  Heidarieh  P,  Habibnia  S,  Rasouli-nasab  M,  Neyestanaki  DK,  Eshraghi  SS, et al. Phenotypic and molecular properties of the Nocardia species. Avicenna J Clin Microbiol Infect 2014; 1: e19215.
• 6.    Bafghi  MF,  Heidarieh  P,  Soori  T,  Saber  S,  Meysamie  A,  Gheitoli  K, et al. Nocardia isolation from clinical samples with the paraffin baiting technique. Germs 2015; 5: 12.
• 7.    Fatahi-Bafghi  M,  Heidarieh  P,  Rasouli-nasab  M,  Habibnia  S,  Hashemi-Shahraki  A,  Eshraghi  SS. Comparison of restriction enzyme pattern analysis and full gene sequencing of 16S rRNA gene for Nocardia species identification: The first report of Nocardia transvalensis isolated of sputum from Iran, and review of the literature. Antonie van Leeuwenhoek 2016; 109: 1285–1298.