Prosthetic joint infection due to Mycobacterium xenopi: a review of the literature with a new case report.

PURPOSE: Extrapulmonary infections due to M. xenopi, particularly osteoarticular localizations, are rare. The purpose of this paper is to describe a case of prosthetic hip infection and to review the published literature on cases of M. xenopi osteoarticular infections. METHODS: Literature search was performed in the following databases: MEDLINE (PubMed), Embase, Central (the Cochrane Library 2019, Issue 1), LILACS (BIREME) (Latin American and Caribbean Health Science Information database) and Clinical Trials databases (14th August 2018). We included all case reports and case series on adult patients diagnosed with bone or joint infection by M. xenopi for whom the treatment and outcome were specified. RESULTS: We retrieved 30 cases published between 1982 and 2012, among which 25 (83.3%) were reported from Europe. The two most common infection sites were spine (12/30, 40%) and knee (9/30, 30%). Risk factors for infection were previous invasive procedures (11/30, 36.7%), autoimmune disease (8/30, 26.7%), AIDS (4/30, 13.3%) and other comorbidities (2/30, 6.7%); five patients had no past medical history. All patients were treated with antibiotic combinations, but composition and duration of regimens hugely varied. Surgical intervention was performed in 16 patients (53.3%). Only 11 patients obtained full recovery of articular mobility after treatment. CONCLUSION: This work highlights the difficulties in diagnosing and treating M. xenopi osteoarticular infections. Globally, evidence supporting the best practice for diagnosis and treatment of this infection is scanty.

[Pulmonary aspergillosis complicating atypical mycobacterial infection in two patients suffering from chronic obstructive pulmonary disease]. / Aspergillose pulmonaire compliquant une infection à mycobactérie atypique chez deux patients atteints de bronchopneumopathie chronique obstructive.

INTRODUCTION: Atypical mycobacteria and Aspergillus are opportunistic organisms responsible for severe pulmonary diseases whose development is encouraged by the presence of chronic obstructive pulmonary disease (COPD) and related immunosuppression. CASE REPORTS: We report the cases of two patients, both alcoholics with emphysematous COPD, who developed chronic pulmonary aspergillosis following atypical mycobacterial infection. Patient 1 developed chronic necrotising aspergillosis several months after the diagnosis of infection with Mycobacterium avium. Patient 2 developed an aspergilloma several weeks after the diagnosis of infection with Mycobacterium xenopi. The association of these two pathologies presents diagnostic and therapeutic problems that are discussed. CONCLUSION: The development of Aspergillus pulmonary disease may complicate atypical mycobacterial infections and explain a poor response to treatment. Our two case reports suggest that a systematic search should be made for pulmonary aspergillosis during the follow-up of patients with atypical mycobacterial infection.

Nontuberculous mycobacteria: susceptibility pattern and prevalence rate in Shanghai from 2005 to 2008.

BACKGROUND: An increasing incidence of disease caused by nontuberculous mycobacteria (NTM) is being reported. The purpose of this study was to determine the isolation rates of NTM from various clinical specimens, and their antimicrobial susceptibility patterns, over a 4-year period in Shanghai. METHODS: All NTM isolated between 2005 and 2008 at Shanghai Pulmonary Hospital, a key laboratory of mycobacteria tuberculosis in Shanghai, China, were identified with conventional biochemical tests and 16S rRNA gene sequencing. Antimicrobial susceptibility for all NTM was determined using the BACTEC MGIT 960 system. RESULTS: A total of 21,221 specimens were cultured, of which 4868 (22.94%) grew acid fast bacilli (AFB), and 248 (5.09%) of the AFB were NTM. The prevalence rate of NTM was determined as 4.26%, 4.70%, 4.96% and 6.38% among mycobacteria culture positive samples in years 2005, 2006, 2007 and 2008 respectively. These data indicated that the prevalence rate has continuously increased. Sixteen different species of NTM were identified, the most commonly encountered NTM in Shanghai were M. chelonae (26.7%), followed by M. fortuitum (15.4%), M. kansasii (14.2%), M. avium-intracellulare complex (13.1%) and M. terrae (6.9%). The rare species identified were M. marinum, M. gastri, M. triviale, M. ulcerans, M. smegmatis, M. phlci, M. gordonae, M. szulgai, M. simiae, M. scrofulaceum and M. xenopi. The five most commonly identified NTM species showed high drug resistance to general anti-tuberculosis drugs, particularly, M. chelonae and M. fortuitum appear to be multi-drug resistance. CONCLUSIONS: The prevalence of NTM in Shanghai showed a tendency to increase over the course of the study. The five most commonly isolated NTM species showed high drug resistance to first line anti-tuberculosis drugs.

Interactions between Mycobacterium xenopi, amoeba and human cells.

Outbreaks due to Mycobacterium xenopi have been linked with contaminated water. M. xenopi has been shown to interact with the biofilm formed in water distribution systems and to be hosted by free-living Acanthamoeba. The present study investigated the interaction between M. xenopi and A. polyphaga amoeba, and between M. xenopi and human fibroblast HEL cells. Examination using the light microscopy together with electronic and confocal microscopy demonstrated that M. xenopi was located within the amoeba and in HEL cells. The Light Cycler measurement of the M. xenopi:A. polyphaga DNA ratio and the M. xenopi:HEL cell DNA ratio demonstrated intra-amoebal and intracellular growth of M. xenopi with doubling-times of five-days and 10 days, respectively. Intra-amoebal M. xenopi survived protozoan encystment and germination. These data demonstrate that M. xenopi is a facultative intra-amoebal and intracellular pathogen. Testing intra-amoebal M. xenopi might be necessary to properly evaluate decontamination procedures for hospital water supply systems in order to achieve eradication.

Mycobacterium xenopi multiplies within human macrophages and enhances HIV replication in vitro.

Mycobacterium xenopi can cause opportunistic infections, particularly in persons infected with human immunodeficiency virus type 1 (HIV-1). The primary focus of this effort was to determine if M. xenopi isolates could survive and grow in human peripheral blood macrophage (MPhi), and if these isolates could promote the replication of HIV-1 in vitro. M. xenopi bacilli survived and replicated 10-fold within 48 h in human MPhi while avirulent Mycobacterium smegmatis, did not grow within the MPhi. M. xenopi bacilli when cultured with peripheral blood mononuclear cells enhanced HIV-1 replication 30- and 50-fold with the macrophage-tropic HIV-1(Ba-L) and 50- and 75-fold with T-cell-tropic strain HIV-1(LAI) by 6 days post-infection when compared to M. smegmatis. The enhanced HIV replication was associated with increased production of TNF-alpha. Partial inhibition of HIV-1 induction was observed using a neutralizing anti-TNF-alpha monoclonal antibody, pentoxifylline, and matrix metalloproteinase (MMP) inhibitor I. Similar mechanisms of pathogenesis among mycobacterial species may help elucidate better treatment approaches in HIV co-infected persons.

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.