Effects of antimicrobials over sessile and planktonic microbiota associated with an industrial cooling water system

Abstract

The bacterial community from a cooling water system was investigated through culture-dependent and independent strategies, and the responses of planktonic and sessile bacteria (grown in glass slides and stainless-steel coupons) to antimicrobials of industrial and clinical use were assessed. The morphotypes with higher biofilm-forming potential were Pseudoxanthomonas sp., Rheinheimera sp., Aeromonas sp. and Staphylococcus sp., and the first also exhibited lower susceptibility to all antibiotics and biocides tested. 16S rRNA high throughput sequencing indicated that Pseudomonadota (77.1% on average, sd 11.1%), Bacteroidota (8.4, sd 5.7%), and Planctomycetota (3.0, sd 1.3%) were the most abundant phyla. KEGG orthologs associated with antibiotics and biocide resistance were abundant in all samples. Although the minimum inhibitory and bactericidal concentrations were generally higher for biofilms, morphotypes in planktonic form also showed high levels of resistance, which could be associated with biofilm cells passing into the planktonic phase. Overall, monochloramine was the most effective biocide.

Keywords:

• Biocides
• antibiotics
• biofilm control
• bacterial community

Acknowledgements

The authors are also thankful to the Department of Microbiology of the Universidade Federal de Minas Gerais for providing research facilities and to the Petróleo Brasileiro S.A. Petrobrás for the access to research and sampling facilities. The authors are grateful to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/Brazil), the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and the Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) for the financial support and fellowship. Additionally, VLS is a research fellow supported by CNPq.

Disclosure statement

The authors report no competing interests.

Data availability statement

The data that support the findings of this study are available upon request.

Additional information

Funding

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/Brazil) (Process 88882.348380/2010-1) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Process 314822/2021-6).