<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Although antibiotic-resistant bacteria (ARB) have been isolated from tap water worldwide, the knowledge of their resistance patterns is still scarce. Both horizontal and vertical gene transfer has been suggested to contribute to the resistance spread among tap water bacteria. In this study, ARB were isolated from finished water collected at two independent water treatment plants (WTPs) and tap water collected at several point-of-use taps during summer and winter sampling campaigns. A total of 24 strains were identified to genus or species level and subjected to antibiotic and disinfectant susceptibility testing. The investigated tap water ARB belonged to phyla <italic>Proteobacteria, Bacteroidetes, Actinobacteria</italic>, and <italic>Firmicutes</italic>. The majority of the isolates proved multidrug resistant and resistant to chemical disinfectant. Neither seasonal nor WTP-dependent variabilities in antibiotic or disinfectant resistance were found. Antibiotics most effective against the investigated isolates included imipenem, tetracyclines, erythromycin, and least effective – aztreonam, cefotaxime, amoxicillin, and ceftazidime. The most resistant strains originate from <italic>Afipia</italic> sp. and <italic>Methylobacterium</italic> sp. Comparing resistance patterns of isolated tap water ARB with literature reports concerning the same genera or species confirms intra-genus or even intra-specific variabilities of environmental bacteria. Neither species-specific nor acquired resistance can be excluded.</p></abstract>

Although antibiotic-resistant bacteria (ARB) have been isolated from tap water worldwide, the knowledge of their resistance patterns is still scarce. Both horizontal and vertical gene transfer has been suggested to contribute to the resistance spread among tap water bacteria. In this study, ARB were isolated from finished water collected at two independent water treatment plants (WTPs) and tap water collected at several point-of-use taps during summer and winter sampling campaigns. A total of 24 strains were identified to genus or species level and subjected to antibiotic and disinfectant susceptibility testing. The investigated tap water ARB belonged to phyla Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes. The majority of the isolates proved multidrug resistant and resistant to chemical disinfectant. Neither seasonal nor WTP-dependent variabilities in antibiotic or disinfectant resistance were found. Antibiotics most effective against the investigated isolates included imipenem, tetracyclines, erythromycin, and least effective – aztreonam, cefotaxime, amoxicillin, and ceftazidime. The most resistant strains originate from Afipia sp. and Methylobacterium sp. Comparing resistance patterns of isolated tap water ARB with literature reports concerning the same genera or species confirms intra-genus or even intra-specific variabilities of environmental bacteria. Neither species-specific nor acquired resistance can be excluded.

Antibiotic and Disinfectant Resistance in Tap Water Strains – Insight into the Resistance of Environmental Bacteria

Polish Journal of Microbiology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Although antibiotic-resistant bacteria (ARB) have been isolated from tap water worldwide, the knowledge of their resistance patterns is still scarce. Both...

Antibiotic and Disinfectant Resistance in Tap Water Strains – Insight into the Resistance of Environmental Bacteria

Article Category: original-paper

Published Online: Mar 19, 2021

Page range: 57 - 67

Received: Oct 24, 2020

Accepted: Jan 11, 2021

DOI: https://doi.org/10.33073/pjm-2021-004

Keywords
susceptibility testing, antibiograms, MIC testing, drinking water bacteria, environmental strains

© 2021 Agata Siedlecka et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Antibiotic and Disinfectant Resistance in Tap Water Strains – Insight into the Resistance of Environmental Bacteria

Article Category: original-paper

Published Online: Mar 19, 2021

Page range: 57 - 67

Received: Oct 24, 2020

Accepted: Jan 11, 2021

DOI: https://doi.org/10.33073/pjm-2021-004

Keywordssusceptibility testing, antibiograms, MIC testing, drinking water bacteria, environmental strains

© 2021 Agata Siedlecka et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
susceptibility testing, antibiograms, MIC testing, drinking water bacteria, environmental strains