Abundance of Mycobacterium avium ssp. hominissuis in soil and dust in Germany - implications for the infection route

The nontuberculous mycobacteria (NTM) are a heterogeneous group of bacteria found in soil, water and dust. The spread of NTM infection depends on the exposure to reservoirs with high proportions of mycobacteria, the virulence of the NTM strains, the enhanced sensitivity to infections such as those of immune-compromised hosts and patient risk factors such as Cystic Fibrosis. Since several decades, NTM lung disease has been increasingly observed in slender postmenopausal women. The most important NTM in Germany is Mycobacterium avium ssp. hominissuis (MAH). The routes of MAH infection are in almost all cases unknown, but water is often suspected as source of infection. We wanted to examine this hypothesis by determining the frequency of MAH in environmental samples of water, biofilms, soil and dust originating from Germany. We found MAH in 33% of the dust samples and 20% of the soil samples. No MAH could be isolated from water and biofilm. Dust and soil clearly presented more abundance of MAH in comparison with water and biofilms. Therefore, more attention should be paid to soil and dust in Germany as an important source of Myco. avium infections.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study was conducted to investigate the ecological abundance of the most prominent clinical nontuberculous mycobacteria (NTM) in Germany, the Mycobacterium avium ssp. hominissuis (MAH). Examination of soil, water, dust and biofilm samples revealed that MAH in Germany was predominant in soil and dust. No MAH was identified in water and biofilms. Our finding contributes to the identification of the environmental niche of this opportunistic pathogen and proposes soil and dust as sources of MAH infection in Germany.

[The use of the Epidemiology Cancer registry Baden-Württemberg in the follow-up of the EPIC cohort]

The European Prospective Investigation into Cancer and Nutrition (EPIC) is a prospective multicentre study that has been implemented to further the understanding of the association between diet and chronic diseases with emphasis on cancer. In Heidelberg from June 1994 until October 1998 about 25,500 subjects aged 35 to 65 years in women and 40 to 65 years in men were recruited. Apart from extensive questions about food intake, the participants were also asked to provide detailed information about their smoking habits, physical activity, subjective well-being, medical history and use of medications. As well as completing the questionnaire and a personal interview, the participants also gave blood samples and anthropometiric measures and the blood pressure were taken in standardized manner. The analyses of the EPIC study will depend on achieving a comprehensive record of all new cancer cases, and all deaths, together with the corresponding cause of death, within the study population. To date all self-reported incident cancer cases are verified by comparing them with pathology reports and hospital records. They are then coded according to the coding list for the International Classification of Diseases (ICD-O2) issued by the World Health Organisation (WHO). Since at begin of the investigation in the study region no cancer registration existed, the participants are followed -up by interval questioning ('active follow-up'). In order to integrate increasingly the data of the Cancer registry Baden-Württemberg (EKR-BW) attempts were made to explore record linkage systems. For this purpose, in the years 2000, 2002, 2003 record linkages between EPIC-Heidelberg and EKR-BW were performed. Procedures were evaluated for performing an anonymous linkage of the EPIC data with the data of the EKR-BW. After a pilot project on the feasibility of the linkage the program was evaluated on the EPIC data, record linkages are performed regularly. Different coding systems were applied. Simultaneously, the EPIC data about on cancer cases among the Heidelberg study participants are passed on to the Cancer Registry, thus contributing to improve completeness of the registry. So far the active follow-up can not be replaced by passive follow-up through record linkage with the cancer registry, but in the long-term it may be possible. Since the technical requirements are complied with, attempts should be made to improve the completeness of the epidemiological cancer registry Baden- Württemberg.