Skip to main content

Catheter-related bloodstream Mycobacterium wolinskyi infection in an umbilical cord blood transplant recipient: a case report



Catheter-related bloodstream infection (CRBSI), caused by rapidly growing mycobacteria (RGM), is a rare infectious complication in hematopoietic stem cell transplant (HSCT) recipients and can often be misdiagnosed as Gram-positive rod (GPR) bacteremia.

Case presentation

We present a case of CRBSI caused by Mycobacterium wolinskyi, a rare RGM, in a 44-year-old female patient who received an umbilical cord blood transplant.


Rapidly growing mycobacteria can stain as GPRs and may grow in routine blood culture media after 3–4 days of incubation. These features are not widely known to clinicians, and acid-fast staining is therefore recommended when unidentifiable GPRs are detected in blood cultures, especially in immunocompromised patients, such as those with hematologic malignancies or intravascular devices.

Peer Review reports


Mycobacterium wolinskyi is a rapidly growing non-tuberculous mycobacteria (NTM) that belongs to the Mycobacterium smegmatis group [1]. Infections caused by M. wolinskyi are rare, with less than 30 cases reported to date. Most of them are skin and soft-tissue infections or prosthetic joint infections after trauma or surgery, and only four were bloodstream infections [2,3,4,5].

In hematopoietic stem cell transplant (HSCT) recipients, catheter-related bloodstream infections (CRBSI) are the most commonly encountered NTM infectious complications [6, 7], mostly caused by rapidly growing mycobacteria (RGM) [7], which are defined as mycobacteria growing within 7 days [8]. They may grow in routine blood culture media after 3–4 days of incubation [8, 9]. However, the diagnosis is often difficult and delayed, since RGM may be misidentified as Gram-positive rods (GPRs) rather than acid-fast bacilli [10,11,12,13,14].

Here, we have described a case of peripherally inserted central catheter-associated bloodstream infection due to M. wolinskyi, diagnosed by acid-fast staining in a second umbilical cord blood transplant recipient. We have also reviewed the clinical course and outcomes of previously reported M. wolinskyi bacteremia.

Case presentation

A 44-year-old woman had undergone first allogeneic cord blood transplantation (CBT, 2.35 × 106/kg nucleated cells, two locus mismatch) for acute myeloid leukemia after two courses of induction therapy that led to hematologic complete remission. The patient was pre-treated with cytarabine, cyclophosphamide, and total body irradiation conditioning. Graft-versus-host disease prophylaxis consisted of cyclosporine and methotrexate. Her medical, family, and social histories were unremarkable. The patient underwent a second CBT (2.0 × 107/kg nucleated cells) 32 days after the first due to graft failure.

Seven days after the second CBT, she presented with high fever and shaking chills. Upon physical examination, painful induration with linear erythema along the superficial veins was observed in the peripherally inserted central catheter (PICC) site, which was inserted on the day after the second CBT. Two sets of blood samples were drawn for culture and meropenem treatment was started. The blood culture was positive on the third day of incubation (10 days after the second CBT). Gram staining of a positive blood culture revealed GPR (Fig. 1, left), and vancomycin was added thereafter. Fever persisted and PICC was removed on day 11 after the second CBT (PICC was maintained for 10 days). The VITEK® 2 system (bioMérieux, Durham, NC, USA) was not able to identify the organism. Blood cultures drawn on days 10, 11, 15, and 22 after CBT were also positive for GPR. On the 14th day after the second CBT, Ziehl–Neelsen staining was performed and was found to be positive for acid-fast bacilli (Fig. 1, right).

Fig. 1
figure 1

Left Gram staining of blood cultures shows diphtheroid bacilli and short branching filaments. Right Ziehl–Neelsen staining of colonies obtained by subculture

The nucleotide sequences were analyzed using the National Center for Biotechnology Information BLAST ( The almost full-length (1442-bp) 16S rDNA gene sequence of the isolate shared 100% similarity to M. wolinskyi type strain ATCC 700010.

In addition to PICC removal, imipenem/cilastatin (IPM/CS), amikacin (AMK), levofloxacin (LVX), and azithromycin (AZM) were started empirically. Antibiotic susceptibilities were determined using the broth microdilution method (BrothMIC RGM®; Kyokuto, Tokyo, Japan) based on the Clinical and Laboratory Standards Institute M24 recommendations (Table 1) [15].

Table 1 Results of antimicrobial susceptibility testing of Mycobacterium wolinskyi isolated in our case

According to the susceptibilities, IPM/CS and AZM were discontinued, and minocycline (MIN) was added. LVX was changed to moxifloxacin (MFX) based on previous case series [4]. After 1 month of intravenous administration of AMK, the patient was discharged on an oral regimen of MFX and MIN. Although MXF had to be discontinued after 4 months due to nausea, MIN was continued for 6 months.

After 3 weeks of combination antimicrobial therapy, blood cultures became negative. She showed successful engraftment by day 28. The patient responded well to therapy and no recurrence of infection was identified at 1-year follow-up.

Discussion and conclusion

Herein, we have described a case of PICC-related bloodstream M. wolinskyi infection in an umbilical cord blood transplant recipient. The findings suggested that acid-fast staining should be conducted when unidentifiable GPRs are detected in blood cultures, especially in immunocompromised patients with long-term indwelling catheters.

Misidentification of RGM as GPRs, including Corynebacterium spp. [11, 14, 16, 17], Rhodococcus, Brevibacterium [10], Actinomyces, or Nocardia [17, 18], had been reported earlier and performing acid-fast staining is recommended for cases in which Gram-positive bacilli have been cultured from high-risk patients. One study at a quality-control center in Switzerland [13], in which investigators delivered M. fortuitum specimens labelled as ‘pus from an abscess’ to 50 laboratory facilities, had shown only 13 of 50 (26%) to be correctly identified as “RGM” or “M. fortuitum”; 46% were incorrectly identified as Nocardia sp., 8% as Rhodococcus sp. Gram-positive rods, Actinomyces, Streptococcus, or Corynebacterium. Notably, all laboratories that did not use acid-fast stains were unable to correctly identify the organisms.

We reviewed all available literature for the five cases of M. wolinskyi bloodstream infections, including the present one (Table 2). Three of the five cases had hematologic malignancies as comorbidities. In all three cases for which Gram stain results were available, blood cultures showed GPRs. An intravascular device was present in 4 of the 5 cases, and the device was removed in 3 cases. Blood cultures were positive within 2 to 5 days of incubation for all cases. The prognosis was generally good, especially for those whose devices had been removed. No death was reported during the treatment.

Table 2 Summary of published cases of M. wolinskyi bacteremia

We reported a case of peripherally inserted central catheter-associated bloodstream infection caused by Mycobacterium wolinskyi in a second umbilical cord blood transplant recipient. M. wolinskyi is an RGM and a rare cause of bacteremia in immunosuppressed patients with hematologic malignancies or intravascular devices.

Rapidly growing mycobacteria may grow in routine blood culture media and sometimes be confused with Gram-positive rods, resulting in delayed diagnosis. In immunocompromised patients or those with intravascular devices and bacteremia caused by “unidentifiable Gram-positive rods”, acid-fast staining should be performed.

Availability of data and materials

Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study.



Catheter-related bloodstream infection


Rapidly growing mycobacteria


Hematopoietic stem cell transplant


Gram-positive rod


Non-tuberculous mycobacteria


Cord blood transplantation


Peripherally inserted central catheter














  1. Brown BA, Springer B, Steingrube VA, et al. Mycobacterium wolinskyi sp. nov. and Mycobacterium goodii sp. nov., two new rapidly growing species related to Mycobacterium smegmatis and associated with human wound infections: a cooperative study from the International Working Group on Mycobacterial Taxonomy. Int J Syst Bacteriol. 1999;49:1493–511.

    Article  CAS  PubMed  Google Scholar 

  2. Chen YC, Jou R, Huang WL, et al. Bacteremia caused by Mycobacterium wolinskyi. Emerg Infect Dis. 2008;14:1818–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  3. Ohno T, Kishimoto W, Chihara D, et al. First case report of sepsis caused by Mycobacterium wolinskyi in chronic myelogenous leukemia. Diagn Microbiol Infect Dis. 2008;62:433–6.

    Article  PubMed  Google Scholar 

  4. Ariza-Heredia EJ, Dababneh AS, Wilhelm MP, et al. Mycobacterium wolinskyi: a case series and review of the literature. Diagn Microbiol Infect Dis. 2011;71:421–7.

    Article  PubMed  Google Scholar 

  5. Kitajima H, Oba Y, Ohira T, et al. First case report of prosthetic valve endocarditis caused by Mycobacterium wolinskyi. J Infect Chemother. 2021;27:766–9.

    Article  PubMed  Google Scholar 

  6. Doucette K, Fishman JA. Nontuberculous mycobacterial infection in hematopoietic stem cell and solid organ transplant recipients. Clin Infect Dis. 2004;38:1428–39.

    Article  PubMed  Google Scholar 

  7. Nagata A, Sekiya N, Najima Y, et al. Nontuberculous mycobacterial bloodstream infections after allogeneic hematopoietic stem cell transplantation. Int J Infect Dis. 2020;97:131–4.

    Article  CAS  PubMed  Google Scholar 

  8. Griffith DE, Aksamit T, Brown-Elliott BA, et al. An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. Am J Respir Crit Care Med. 2007;175:367–416.

    Article  CAS  PubMed  Google Scholar 

  9. Hawkins C, Qi C, Warren J, Stosor V, et al. Catheter-related bloodstream infections caused by rapidly growing nontuberculous mycobacteria: a case series including rare species. Diagn Microbiol Infect Dis. 2008;61:187–91.

    Article  PubMed  Google Scholar 

  10. Takekoshi D, Al-Heeti O, Belvitch P, et al. Native-valve endocarditis caused by Mycobacterium chelonae, misidentified as polymicrobial Gram-positive bacillus infection. J Infect Chemother. 2013;19:754–6.

    Article  PubMed  Google Scholar 

  11. Williamson JC, Miano TA, Morgan MR, et al. Fatal Mycobacterium abscessus endocarditis misidentified as Corynebacterium spp. Scand J Infect Dis. 2010;42:222–4.

    Article  PubMed  Google Scholar 

  12. Garg P, Athmanathan S, Rao GN. Mycobacterium chelonei masquerading as Corynebacterium in a case of infectious keratitis: a diagnostic dilemma. Cornea. 1998;17:230–2.

    Article  CAS  PubMed  Google Scholar 

  13. von Graevenitz A, Pünter-Streit V. Failure to recognize rapidly growing mycobacteria in a proficiency testing sample without specific request—a wider diagnostic problem? Eur J Epidemiol. 1998;14:519–20.

    Article  Google Scholar 

  14. Larkin JA, Shashy RG, Gonzalez CA. Difficulties in differentiating a rapidly growing Mycobacterium species from diphtheroids in an immunocompromised patient. Clin Microbiol Newsl. 1997;19:108–11.

    Article  Google Scholar 

  15. CLSI. Susceptibility testing of Mycobacteria, Nocardia spp., and other aerobic actinomycetes. CLSI standard M24. 3rd ed. Wayne: Clinical and Laboratory Standard Institute; 2018.

    Google Scholar 

  16. Marshall C, Samuel J, Galloway A, et al. Mycobacterium mucogenicum from the Hickman line of an immunocompromised patient. Case reports. J Clin Pathol. 2008;61:140–1.

    Article  CAS  PubMed  Google Scholar 

  17. Rodgers GL, Mortensen JE, Blecker-Shelly D, et al. Two case reports and review of vascular catheter-associated bacteremia caused by nontuberculous Mycobacterium species. Pediatr Infect Dis J. 1996;15:260–4.

    Article  CAS  PubMed  Google Scholar 

  18. Short WR, Emery C, Bhandary M, et al. Misidentification of Mycobacterium peregrinum, the causal organism of a case of bacteremia and automatic implantable cardioverter defibrillator-associated infection, due to its unusual acid-fast staining characteristics. J Clin Microbiol. 2005;43:2015–7.

    Article  PubMed  PubMed Central  Google Scholar 

Download references


We sincerely appreciate that the patient agreed to publish this report.


No funding was obtained for this study.

Author information

Authors and Affiliations



EM conceptualized the manuscript structure, curated data and wrote the original draft of the manuscript. RH collaborated in organizing the information, in the literature review and discussion, in writing important parts of the manuscript and revising it extensively. RH and YU explained the implications of this article to the patient and obtained her consent. EM, RH and YU were involved in the patient’s care. TW and YO were responsible for the identification of this organism. NH edited the manuscript and critically reviewed the scientific and formal content. All authors critically revised the manuscript and approved the final manuscript.

Corresponding author

Correspondence to Emiri Muranaka.

Ethics declarations

Ethics approval and consent to participate

Ethics approval was not required and the patient gave her written consent to participate.

Consent for publication

The patient gave both oral and written informed consent to the publication of her case (including her personal and clinical details). The data presented in this case report do not allow identification of the patient.

Competing interests

The authors declare no competing interests.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Muranaka, E., Hase, R., Utsu, Y. et al. Catheter-related bloodstream Mycobacterium wolinskyi infection in an umbilical cord blood transplant recipient: a case report. BMC Infect Dis 22, 520 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: