Mycobacterium malmoense lymphadenitis in Spain: first two cases in immunocompetent patients

Abstract number: 902_p1506

López-Calleja A.I.


Mycobacterium malmoense is a slow-growing, non-photochromogenic mycobacterium that has been recognised as nontuberculous pathogen in northern and northwestern Europe. Recently, it has been isolated from clinical samples in other areas. It can cause pulmonary and extrapulmonary disease and also disseminated infection.

The objective is to present two cases of M. malmoense lymphadenitis in two immunocompetent children in Spain. These are the first documented cases of extrapulmonary infection by M. malmoense in our country.

Case report and methods:

Two patients, an eight-year-old boy and a two-year-old girl were referred for evaluation of an enlarged painless superficial lymph node on the cervical area. One fine needle aspiration biopsy was performed in both cases to establish the diagnosis. Specimens were decontaminated and seeded onto Löwenstein–Jensen slants and into a liquid system, the BacT/Alert(R) MP (BioMérieux, inc. Durham).


Microscopic examination of specimens yielded few acid-fast bacilli in both cases. Cultures in liquid medium showed growth of mycobacteria after 72 days in the first case, and 36 days in the second. Primary cultures on Löwenstein–Jensen remained negative after 75 days. Cultures were confirmed as slow-growing mycobacteria, non-photochromogenic; M. malmoense was identified by polymerase chain reaction and restriction enzyme pattern analysis (PRA) and on analysis of the 16S-rRNA gene


Unilateral cervical lymphadenitis is the most frequent extrapulmonary infection due to M. malmoense, and predominantly affects children. To ensure a sensitive primary isolation of M. malmoense, it is crucial to carefully choose culture media and conditions. New clinical isolates from different countries and the isolation from the environment question the fact that M. malmoense is exclusively limited to specific zones. Probably, M. malmoense is present in many geographic areas and may colonise or cause infections in humans and animals. We want to draw the attention of microbiologists and clinicians to this emergent pathogen that should be added to the list of nontuberculous mycobacteria responsible for disease in immunocompetent patients.


Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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