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Bacterial diversity and antibiotic resistance in water habitats: searching the links with the human microbiome

Publication . Vaz-Moreira, Ivone; Nunes, Olga C.; Manaia, Celia M.

Water is one of the most important bacterial habitats on Earth. As such, water represents also a major way of dissemination of bacteria between different environmental compartments. Human activities led to the creation of the so-called urban water cycle, comprising different sectors (waste, surface, drinking water), among which bacteria can hypothetically be exchanged. Therefore, bacteria can be mobilized between unclean water habitats (e.g. wastewater) and clean or pristine water environments (e.g. disinfected and spring drinking water) and eventually reach humans. In addition, bacteria can also transfer mobile genetic elements between different water types, other environments (e.g. soil) and humans. These processes may involve antibiotic resistant bacteria and antibiotic resistance genes. In this review, the hypothesis that some bacteria may share different water compartments and be also hosted by humans is discussed based on the comparison of the bacterial diversity in different types of water and with the human-associated microbiome. The role of such bacteria as potential disseminators of antibiotic resistance and the inference that currently only a small fraction of the clinically relevant antibiotic resistome may be known is discussed.

2014Journal article

Open access

Biodegradation of sulfamethoxazole and other sulfonamides by Achromobacter denitrificans PR1

Publication . Reis, Patrícia J. M.; Reis, Ana C.; Ricken, Benjamin; Kolvenbach, Boris A.; Manaia, Célia M.; Corvini, Philippe F.X.; Nunes, Olga C.

This study aimed to isolate and characterize a microbial culture able to degrade sulfonamides. Sul-famethoxazole (SMX)-degrading microorganisms were enriched from activated sludge and wastewater.The resultant mixed culture was composed of four bacterial strains, out of which only Achromobacterdenitrificans PR1 could degrade SMX. This sulfonamide was used as sole source of carbon, nitrogen andenergy with stoichiometric accumulation of 3-amino-5-methylisoxazole. Strain PR1 was able to removeSMX at a rate of 73.6 ± 9.6 molSMX/gcell dry weighth. This rate more than doubled when a supplement ofamino acids or the other members of the mixed culture were added. Besides SMX, strain PR1 was able todegrade other sulfonamides with anti-microbial activity. Other environmental Achromobacter spp. couldnot degrade SMX, suggesting that this property is not broadly distributed in members of this genus.Further studies are needed to shed additional light on the genetics and enzymology of this process.

2014Journal article

Open access