Osteomyelitis Because of Mycobacterium Xenopi in an Immunocompetent Child.

We present the case of a 6-year-old, immunocompetent boy with chronic osteomyelitis of the calcaneus caused by Mycobacterium xenopi. Of note, typical histopathology was not visible on the first biopsy and developed only later over a period of 6 weeks, highlighting the difficult differential diagnosis of osteomyelitis caused by nontuberculous mycobacteria.

Multilocus sequence typing of Mycobacterium xenopi.

Mycobacterium xenopi is an opportunistic mycobacterial pathogen of increasing clinical importance. Surveillance of M. xenopi is hampered by the absence of tools for genotyping and molecular epidemiology. In this study, we describe the development and evaluation of an effective multilocus sequence typing strategy for M. xenopi.

Mycobacterium heckeshornense lung infection that was diagnosed as Mycobacterium xenopi disease by DNA-DNA hybridization (DDH).

The DNA sequencing analyses of the 16S rRNA gene, rpoB and hsp65 were conducted to characterize six strains that had been identified as Mycobacterium xenopi by DNA-DNA hybridization (DDH) for past ten years in our hospital. The results revealed Mycobacterium heckeshornense infection in one of the six cases. A 47-year-old man, who had been treated for pneumonia, had pulmonary nontuberculous mycobacterial disease. The sputa from the patient were culture positive for mycobacterium in three times. And it was diagnosed as M. xenopiby DDH method. Chest X-ray showed fibrocavitary lesion in right upper lobe was successfully treated with clarithromycin for four weeks.

Unreliable detection of Mycobacterium xenopi by the nonradiometric Bactec MGIT 960 culture system.

From June 2006 to December 2007, 3,648 clinical specimens consecutively received for mycobacterial culture were investigated. Each processed sample was inoculated into Bactec MGIT 960 liquid medium and a Löwenstein-Jensen slant. Tubes that were flagged as positive by the instrument as well as those determined to be negative after 42 days of incubation were removed, visually inspected for growth, and checked for the presence of acid-fast bacilli. Three hundred sixty-nine mycobacterial strains were recovered; of the 44 Mycobacterium xenopi isolates recovered by MGIT medium, only 13 were detected by the instrument (P<0.0001). Most tubes yielding M. xenopi exhibited a peculiar pattern of growth characterized by a scant number of round, yellow-pigmented granules instead of the fine, evenly dispersed clumps usually observed for mycobacteria. It is suggested to check all individual tubes discarded by the MGIT 960 system at the end of the incubation period to prevent a significant amount of previously undetected growth from being missed.

Pulmonary disease caused by Mycobacterium xenopi: the first case in Korea.

Mycobacterium xenopi is a nontuberculous mycobacterium (NTM) that rarely causes pulmonary disease in Asia. Here we describe the first case of M. xenopi pulmonary disease in Korea. A 66-year-old man was admitted to our hospital with a 2-month history of productive cough and hemoptysis. His past medical history included pulmonary tuberculosis 44 years earlier, leading to a right upper lobectomy. Chest X-ray upon admission revealed cavitary consolidation involving the entire right lung. Numerous acid-fast bacilli were seen in his initial sputum, and M. xenopi was subsequently identified in more than five sputum cultures, using molecular methods. Despite treatment with clarithromycin, rifampicin, ethambutol, and streptomycin, the infiltrative shadow revealed on chest X-ray increased in size. The patient's condition worsened, and a right completion pneumonectomy was performed. The patient consequently died of respiratory failure on postoperative day 47, secondary to the development of a late bronchopleural fistula. This case serves as a reminder to clinicians that the incidence of NTM infection is increasing in Korea and that unusual NTM are capable of causing disease in non-immunocompromised patients.

Pulmonary Disease Caused by Mycobacterium xenopi: The First Case in Korea

Mycobacterium xenopi is a nontuberculous mycobacterium (NTM) that rarely causes pulmonary disease in Asia. Here we describe the first case of M. xenopi pulmonary disease in Korea. A 66-year-old man was admitted to our hospital with a 2-month history of productive cough and hemoptysis. His past medical history included pulmonary tuberculosis 44 years earlier, leading to a right upper lobectomy. Chest X-ray upon admission revealed cavitary consolidation involving the entire right lung. Numerous acid-fast bacilli were seen in his initial sputum, and M. xenopi was subsequently identified in more than five sputum cultures, using molecular methods. Despite treatment with clarithromycin, rifampicin, ethambutol, and streptomycin, the infiltrative shadow revealed on chest X-ray increased in size. The patient's condition worsened, and a right completion pneumonectomy was performed. The patient consequently died of respiratory failure on postoperative day 47, secondary to the development of a late bronchopleural fistula. This case serves as a reminder to clinicians that the incidence of NTM infection is increasing in Korea and that unusual NTM are capable of causing disease in non-immunocompromised patients.

A decade surveillance study of Mycobacterium xenopi disease and antimicrobial susceptibility levels in a reference teaching hospital of northern Italy: HIV-associated versus non-HIV-associated infection.

OBJECTIVE AND METHOD: The aim of our survey is to investigate the epidemiology and in vitro antimicrobial susceptibility levels of 35 consecutive Mycobacterium xenopi strains responsible for confirmed disease at a University Hospital from 1993 to 2002 and to identify eventual differences in the in vitro sensitivity profile between the 17 strains isolated from patients with HIV disease and the 18 isolates cultured from non-HIV-infected individuals. RESULTS: The involvement of lower airways accounted for 88.6% of cases; but atypical pulmonary findings, including cavitation and a prominent inflammatory reaction, recently emerged in HIV-infected patients successfully treated with HAART, which raises the possible role of immune reconstitution syndrome in the clinical pathomorphism of this opportunistic disease. When compared with non-HIV-infected patients, patients with HIV disease had a lower mean age and a tendency to suffer from late relapses. The greatest overall in vitro sensitivity rate was registered for capreomycin and protionamide (100% of strains) followed by kanamicin (96.6%), whereas susceptibility rates for the first-line compounds such as ethambutol, isoniazid, and rifampicin were slightly lower (85.7% to 91.4%). No temporal variation in the susceptibility index was seen over the study decade. Non-HIV-infected patients experienced a higher frequency of M. xenopi isolates that proved to be resistant to at least one tested compound compared with HIV-associated episodes, despite the heavy and prolonged exposure of HIV-infected patients to broad spectrum antimicrobials, which included agents effective on atypical mycobacteria. Only one HIV-positive patient developed rifampicin resistance in his third disease recurrence. CONCLUSION: A rapid diagnosis, a reliable differentiation between colonization and disease, and an optimal therapeutic choice for atypical mycobacterial disease (including M. xenopi one) are still serious challenges for clinicians and bacteriologists who treat immunocompromised patients, such as those with HIV disease. In the immunocompromised host, diagnostic difficulties posed by late identification and eventually concurrent opportunistic disorders add their negative effects to therapeutic problems due to the unpredictable in vitro susceptibility profile of atypical mycobacteria, such as M. xenopi.

Identification of three strains of Mycobacterium species isolated from clinical samples using fatty acid methyl ester profiling.

The cellular fatty acid profiles of 67 strains belonging to three different species of the genus Mycobacterium were determined by gas chromatography of the fatty acid methyl esters, using the MIDI Sherlock Microbial Identification System (MIS). The species M. tuberculosis, M. xenopi and M. avium complex were clearly distinguishable and could be identified based on the presence and concentrations of 12 fatty acids: 14:0, 15:0, 16:1 omega 7c, 16:1 omega 6c, 16:0, 17:0, 18:2 omega 6.9c, 18:1 omega 9c, 18:0, 10Me-18:0 tuberculostearic acid, alcohol and cyclopropane. Fatty acid analysis showed that there is great homogeneity within and heterogeneity between Mycobacterium species. Thus the MIS is an accurate, efficient and relatively rapid method for the identification of mycobacteria.

Identification of Mycobacterium xenopi by gas chromatography.

For the purposes of the following study we cultured 32 strains of Mycobacterium xenopi isolated from clinical specimens and several strains of other slowly growing mycobacteria. The cultures were grown in liquid medium and then analysed--after saponification, methylation, extraction with organic solvent and washing of the organic phase--using a highly sensitive manual gas-liquid chromatographic assay for the determination of secondary alcohol 2-OH-docosanol. The percentage of this compound was compared with that previously measured in strains of Mycobacterium xenopi grown on solid medium. The presence of this specific alcohol was always apparent, even though its quantity was lower than that obtained by growing mycobacteria on solid medium. The absence of interference peaks around the compound was checked by analyzing strains of other slowly growing mycobacteria in the same conditions.

Mycobacterium xenopi and related organisms isolated from stream waters in Finland and description of Mycobacterium botniense sp. nov.

Three scotochromogenic Mycobacterium xenopi-like organisms were isolated from stream waters in Finland. These strains grew at 36-50 degrees C but not at 30 degrees C. One of the three strains was fully compatible with the M. xenopi type strain according to GLC-MS, biochemical tests, and 16S rDNA and 16S-23S rDNA internal transcribed spacer (ITS) sequencing. Two of the strains closely resembled M. xenopi in lipid analyses and biochemical tests, but analysis by GLC-MS verified the presence of two new marker fatty acids (2,4,6,x-tetramethyl-eicosanoic acid and 2,4,6,x,x-pentamethyl-docosanoic acid). The 16S rDNA and ITS region sequences of these two strains differed from those of M. xenopi and other previously described mycobacterial sequences. Therefore, the strains are regarded as new species of slow-growing mycobacteria, for which the name Mycobacterium botniense sp. nov. is proposed. The chemical, physical and microbiological quality of the water reservoirs of M. xenopi and M. botniense are described. As far as is known, this is the first time that M. xenopi has been isolated from natural waters. The strains of M. botniense sp. nov. (E347T and E43) have been deposited in the ATCC as strains 700701T and 700702, respectively.

Mycobacterial linear plasmids have an invertron-like structure related to other linear replicons in actinomycetes.

The authors previously identified large plasmids in Mycobacterium xenopi, M. branderi and M. celatum which appeared to have a linear topology. This study has confirmed the presence of such linear plasmids in mycobacteria, including M. avium, and demonstrated that the ends of these replicons are covalently bound with protein(s), suggesting an invertron-like structure. The termini of one 25 kb plasmid, designated pCLP, from M. celatum were cloned and the first 500 bp of each terminus were sequenced. The termini of this plasmid show the characteristic features of invertrons with terminal inverted repeats of 45 bp (with imperfect matches) and several palindromic sequences. Moreover, similarity existed in the structure and terminal nucleotide sequence of pCLP and the termini of linear replicons of Streptomyces and Rhodococcus species, indicating a conservation of these linear extrachromosomal elements within the Actinomycetales.

[Manifestations, diagnosis and treatment of non-tuberculous mycobacterial infections in non-immunodepressed patients]. / Manifestations, diagnostics et traitements des mycobactérioses non tuberculeuses chez le sujet non immunodéprimé.

Non-tuberculous mycobacteria (NTM) can be the etiologic agents of chronic pulmonary disease, lymphadenitis, skin and soft-tissue infection and disseminated disease in non-immunocompromised patients. The recognition of disease needs repeated isolation of the NTM from bronchopulmonary secretions or from tissue biopsies, and its identification by specific laboratory methods. A wide spectrum of clinical presentations and severity of disease can be found, from spontaneous healing to progressive and destructive lung disease, and death, according to predisposing conditions and mycobacterial species. The choice of surgical and drug treatment will depend on identification of specific pathogen and clinical evaluation.