DNA-based detection of Mycobacterium avium subsp. paratuberculosis in domestic and municipal water from Porto (Portugal), an area of high IBD prevalence

Telma Sousa; Marta Costa; Pedro Sarmento; Maria Conceição Manso; Cristina Abreu; Tim J Bull; José Cabeda; Amélia Sarmento

doi:10.3934/microbiol.2021011

DNA-based detection of Mycobacterium avium subsp. paratuberculosis in domestic and municipal water from Porto (Portugal), an area of high IBD prevalence

AIMS Microbiol. 2021 May 17;7(2):163-174. doi: 10.3934/microbiol.2021011. eCollection 2021.

Authors

Telma Sousa^{1

2}, Marta Costa^{1

2}, Pedro Sarmento³, Maria Conceição Manso^{1

2}, Cristina Abreu^{1

2}, Tim J Bull⁴, José Cabeda^{1

5

6}, Amélia Sarmento^{1

2

7}

Affiliations

¹ FP-ENAS (UFP Energy, Environment and Health Research Unit), Universidade Fernando Pessoa, Rua Carlos da Maia, 296 - 4200-150 Porto, Portugal.
² Faculdade de Ciências da Saúde, Universidade Fernando Pessoa, Rua Carlos da Maia, 296 - 4200-150 Porto, Portugal.
³ Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
⁴ Institute of Infection and Immunity, St George's University of London, Cranmer Terrace London SW17 0RE, UK.
⁵ Escola Superior de Saúde Fernando Pessoa, Rua Delfim Maia, 334 - 4200-253 Porto, Portugal.
⁶ Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Avenida General Norton de Matos, 4450-208 Matosinhos, Portugal.
⁷ I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208 - 4200-135 Porto, Portugal.

Abstract

Mycobacterium avium subsp. paratuberculosis (MAP) may play a role in the pathology of human inflammatory bowel disease (IBD). Previously, we found a high frequency (98% in patients with active disease) of MAP DNA detection in the blood of Portuguese Crohn's Disease patients, suggesting this cohort has high exposure to MAP organisms. Water is an important route for MAP dissemination, in this study we therefore aimed to assess MAP contamination within water sources in Porto area (the residential area of our IBD study cohort). Water and biofilms were collected in a wide variety of locations within the Porto area, including taps connected to domestic water sources and from municipal water distribution systems. Baseline samples were collected in early autumn plus further domestic water samples in early winter, to assess the effect of winter rainfall. DNA was extracted from all 131 samples and IS900-based nested PCR used to assess the frequency of MAP presence. Our results show high MAP positivity in municipal water sources (20.7% of water samples and 41.4% of biofilm samples) and even higher amongst domestic sources (30.8% of water samples and 50% of biofilm samples). MAP positivity in biofilms correlated with positivity in water samples from the same sources. A significantly higher frequency of MAP-positivity was observed during winter rains as compared with samples collected in autumn prior to the winter rainfall period (61.9% versus 30.8%). We conclude that domestic and municipal water sources of Porto region have a high burden of MAP contamination and this prevalence increases with rainfall. We hypothesize that human exposure to MAP from local water supplies is commonplace and represents a major route for MAP transmission and challenge which, if positively linked to disease pathology, may contribute to the observed high prevalence of IBD in Porto district.

Keywords: MAP detection; Mycobacterium avium subsp. paratuberculosis; inflammatory bowel disease; water contamination.