Monitoring of thermotolerant coliforms and their antibiotic resistance in the Marombas river sub-basin

Abstract

The presence of antibiotic-resistant coliforms, despite not being a criterion considered by legislation, is a serious and worrying aspect because it causes difficult-to-treat illnesses and deaths. The present study evaluated the concentration of thermotolerant coliforms and their resistance to ampicillin, ciprofloxacin and tetracycline in four rivers in the Marombas River Sub-basin, in Santa Catarina. Analyses were carried on bimonthly for one year. Data were subjected to analysis of variance and the means were separated by the Tukey test. The average number of thermotolerant coliforms was 709 ^. 100 mL^-1, corresponding to class 2, indicated for animal consumption and irrigation, in accordance with the water use made by the population. However, 41% of coliform isolates were resistant to ampicillin, while 10% were resistant to tetracycline and ciprofloxacin. Resistant isolates were found in all rivers and in all sampling dates, which indicates a high frequency and abundant spread of these microorganisms. The presence of antibiotic-resistant bacteria in water can cause serious human and animal health problems, in addition to contaminating the soil when used for irrigation, causing negative impacts on the environment and the entire ecosystem. Therefore, the importance of monitoring resistant bacteria in water, the need for environmental conservation programs and the rational and correct use of antibiotics is highlighted, in order to minimize the occurrence of microbial resistance.

Key words: antimicrobial resistance; microbiological water quality; thermotolerant coliforms.