Comment on: Disseminated Nocardia cyriacigeorgia causing pancreatitis in a haploidentical stem cell transplant recipient.

To the Editor,

Chen et al. recently published their report on Disseminated Nocardia cyriacigeorgia causing pancreatitis in a haploidentical stem cell transplant recipient [1]. The genus Nocardia are partially acid-fast, Gram-positive and relatively slow growth bacteria which are lives in environment resources such as water, soil, milk and decaying vegetable. These group of bacteria cause dangerous infectious disease, nocardiosis, by entering the respiratory tract or traumatic inclusion. Accurate identification at the genus level includes: colonial morphology, Gram stain, partially acid-fast, growth in lysozyme broth, biochemical test (Hydrolysis of amino acids such as hypoxanthine, xanthine, tyrosine, casein, gelatin and urea, production of nitrate reductase, growth at 35 °C and 45 °C, and utilization of some carbohydrates) and molecular methods such as PCR-sequencing and PCR-RFLP using 16S rRNA, hsp65, 16–23S rRNA (ITS), rpoB and secA. Moreover, appropriate treatment of nocardial infections depends on accurate identification of Nocardia species because each species are different susceptibility drug patterns [2], [3].

I’m request the authors attend to the following questions.

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

Based on scientific evidence, growth in lysozyme broth is important for the genus Nocardia identification [4]. but in this study, used of Gram-stain and partially acid-fast characteristics. While according to the reports, other partially acid-fast bacteria such as Rhodococcus and Gordonia are able cause of disseminated and blood-stream infections [5], [6]. therefore, please explain how Nocardia was identified at the genus level.