Nosocomial disseminated Mycobacterium chelonae infection in an immunocompromised patient

ARTICLE

Auteur(s) : Emilie Sbidian^a1, Nora Kramkimel^a1, Emilie Routier¹, Sorin Bularca¹, Tu-Anh Duong¹, Jean-Claude Roujeau¹, Philippe Legrand², Lionel Deforges², Martine Bagot¹

¹Service de Dermatologie, Hôpital Henri Mondor, 51 avenue du Maréchal de Lattre de Tassigny, 94 010 Créteil, France
²Department of Bacteriology-Virology, Henri Mondor Hospital, AP-HP, Créteil, France

Non-tuberculosis mycobacteria (NTM) are environmental saprophytes. Contamination of hospital drinking water systems by NTM is a known cause of nosocomial infections [1]. Most nosocomial NTM infection outbreaks are caused by M. fortuitum and M. abscessus [2]. Here, we report a sporadic case of probable nosocomial disseminated infection due to Mycobacterium chelonae.

A 62-year-old man was admitted for extensive eczema. His medical history reported dialysis, cardiomyopathy and colostomy perforation. His eczema was improved by using topical steroids and balneotherapy with tap-water. 3 weeks after the beginning of treatment, diffuse abscesses appeared on the limbs. There was no fever. Cultures of the lesions were sterile for conventional bacteriology and fungi. However, he was, initially, treated with intravenous penicillin, surgical debridement and skin care with antiseptics diluted in tap water, without improvement. New samples were taken from the abscesses. Histopathological analysis of skin biopsies showed granulomatous lesions with focal neutrophil abscesses and no evidence of acid fast bacilli. The specimen cultures grew M.chelonae. Multifocal osteomyelitis was directly related to the cutaneous lesions. Discovertebral biopsy showed an inflammatory cell infitrate with no germs. Blood cultures were negative and transthoracic echocardiography was normal. In order to determine the M. chelonae source, tap water samples were collected from his hospital room and from the dialysis departments (usual and hospital ones); the samples were filtered through a sterile cellulose nitrate membrane then the filter membranes were used for culture, without preliminary decontamination. Typing of M. chelonae strains was performed using pulsed-field gel electrophoresis (PFGE) with XbaI as the restriction enzyme at the National Reference Centre laboratory, as described previously [3]. The PFGE patterns of M.chelonae isolated from the patient and from hospital tap water were different. The final diagnosis was probable nosocomially acquired infection with M. chelonae, though the source of contamination was not clearly identified. No other case was detected following this one. The patient was initially treated with clarithromycin, tobramycin and tygacyl. He developed refractory disease and interferon gamma was administered in addition to other antimycobacterial medications. The skin lesions ultimately progressed and the patient died several weeks later because of acute hemodynamic compromise during dialysis.

M. chelonae is mostly responsible for cutaneous and soft tissue infections such as abscesses, cellulitis or ulcers [4]. It is also associated with ocular and pulmonary infections [5]. Disseminated infections due to M. chelonae usually present with disseminated cutaneous lesions [4] and have been reported in severely immunocompromised subjects (lymphoma and leukemia, cell-mediated immunodeficiency, AIDS, immunosuppressive drugs for longer than 6 months). There are 2 categories of sources: the natural environment (streams, ground-water [6]…) and the built environment (swimming-pools, cooling towers [5]…). Among built sources, contaminated hospital water systems are being recognized with increasing frequency as responsible for nosocomial infections. M. chelonae infections have been reported following liposuction [2], mesotherapy injections or the use of contaminated endoscopes. Despite the absence of similarity between the M.chelonae isolated from our patient and from hospital tap water, we suspected that the M. chelonae infection may have resulted from the application of contaminated water on eczema lesional skin (balneotherapy with tap-water first, then skin care with antiseptics diluted in tap water). Moreover, the abscesses were not present on admission to our hospital. In all previously published hospital cases, the hospital reservoir of water was found to contain M. chelonae. Even though the concentration of NTM in these water samples was not clearly associated with higher risk, it is important to consider tap water as a possible source for infections. Prevention of these outbreaks could consist of guidelines for medical instrument disinfection, antibioprophylaxis for patients at high risk of NTM infections [1] and the use of sterile fluids (water or saline) in skin care.

Acknowledgements

References

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3 Carbonne A, Brossier F, Arnaud I, et al. Outbreak of nontuberculous mycobacterial subcutaneous infections related to multiple mesotherapy injections. J Clin Microbiol 2009; 47: 1961-4.

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5 Hsieh HC, Lu PL, Chen TC, et al. Mycobacterium chelonae empyema in an immunocompetent patient. J Med Microbiol 2008; 57: 664-7.

6 Pagnier I, Merchat M, Raoult D, La Scola B. Emerging Mycobacteria spp. in cooling towers. Emerg Infect Dis 2009; 15: 121-2.

a The two first authors contributed equally to this work.