The aims of this study were to determine the microbial community in five rivers in the proximity of a city in the Czech Republic using 454-pyrosequencing, as well as to assess seasonal variability over the course of 1 year and to identify the factors influencing the structure of bacterial communities. Samples from five rivers around the city of Brno were obtained during four seasons and analysed using 454 pyrosequencing of the 16S rRNA gene. The core composition of bacterial communities consisted of Actinobacteria, Bacteroidetes, Proteobacteria, Firmicutes, Fusobacteria, TM7 and others. Our approach enabled us to more closely study the correlation between the abundance of different families and environmental factors. Overall, Actinobacteria negatively correlated with phosphorus, sulphate, dissolved particle and chloride levels. In contrast, Proteobacteria positively correlated with sulphate, dissolved particle, chloride, dissolved oxygen and nitrite levels. Future work should focus on the dynamics of bacterial communities present in river water and their relation to the overall stability of the water ecosystem.

An excessive use of antimicrobial agents poses a risk for the selection of resistant bacteria. Of particular interest are antibiotics that have large consumption rates in both veterinary and human medicine, such as the tetracyclines and macrolide-lincosamide-streptogramin (MLS) group of...

The environment is a reservoir of nontuberculous mycobacteria and is considered a source of infection for animals and humans. Mycobacteria can persist in different types of environments for a relatively long time. We have studied their possible internalization into plant tissue through intact, as well as damaged, root systems of different types of plants grown in vitro and under field conditions. The substrate into which plants were seeded was previously contaminated with different strains of Mycobacterium avium (10 ⁸ to 10 ¹⁰ cells/g of soil) and feces from animals with paratuberculosis. We detected M. avium subsp. avium , hominissuis , and paratuberculosis in the stems and leaves of the plants by both culture and real-time quantitative PCR. The presence of mycobacteria in the plant tissues was confirmed by microscopy. The concentration of mycobacteria found inside plant tissue was several orders of magnitude lower (up to 10 ⁴ cells/g of tissue) than the initial concentration of mycobacteria present in the culture medium or substrate. These findings led us to the hypothesis that plants may play a role in the spread and transmission of mycobacteria to other organisms in the environment.

Non-tuberculous mycobacteria are increasingly described as infectious agents in immunocompromised patients. A 17-year-old male patient suffering from secondary non-Hodgkin's lymphoma and treated with chemotherapeutic agents was admitted to hospital due to pleuropneumonia. Mycobacterium neoaurum was cultured repeatedly from his sputum and, Mycobacterium avium subsp. avium (M. a. avium) was detected by IS901 qPCR from detached fragments of his intestinal mucosa. We attempted to determine the possible sources of infection by analysing environmental samples from the closed oncology unit and conventional unit in the hospital, and from the patient's home residence and places which he frequented. The environment of the patient harboured mycobacteria (41 isolates in total); however, M. neoaurum was not recovered. M. a. avium was detected by qPCR in the environmental samples from a small flock of hens kept by his neighbour. Although it was not confirmed by DNA fingerprinting methods, the M. a. avium infection could have been acquired through the eating of incompletely cooked eggs.