MICROBIOLOGICAL ANALYSIS OF WATER AND ANTIMICROBIAL SENSITIVITY PROFILE OF Escherichia coli STRAINS ISOLATED FROM THE CACHOEIRA RESERVOIR IN SOBRAL–CE

Abstract

Water is essential for health, but uncontrolled urbanization has compromised its quality through contamination with effluents and pesticides. At the Cachoeira reservoir in Sobral, Ceará, which is used for various activities, the presence of solid waste, murky water, and livestock indicates possible sources of pollution. Water quality is monitored by bioindicator microorganisms, and contamination can contribute to the spread of antibiotic-resistant bacteria, making isolation, identification, and sensitivity testing of microorganisms essential. This research aimed to evaluate the microbiological conditions of the Cachoeira reservoir and to outline the sensitivity profile of Escherichia coli strains to antibiotics. Four collections were carried out at three different points, totaling twelve samples. The analyses included the determination of the Most Probable Number of total and thermotolerant coliforms, the count of mesophilic aerobic bacteria, biochemical tests of the IMViC, and antibiogram for analysis of the antimicrobial sensitivity profile. The results showed that total coliforms ranged from 3x10¹ to 1.6x10³ CT/mL, exceeding the legal limit, while thermotolerant coliforms were within the established parameters, ranging from <2.5x10¹ to 1.4x10² CTT/100mL. The count of mesophilic aerobes was <2.5x10¹ to 2.5x10⁵ CFU/mL, exceeding the limits in the first three collections. The Escherichia coli strains were sensitive to Azithromycin, but some showed resistance to Ciprofloxacin, Gentamicin, and Imipenem. It is concluded that the water is unfit for human consumption and may contribute to the spread of resistant bacteria. Therefore, continuous monitoring is necessary to avoid contamination and spread of resistant bacteria. It is concluded that the water is suitable for recreation and animal drinking but unsuitable for human consumption, in addition to favoring the spread of resistant bacteria. Therefore, continuous monitoring is necessary to avoid contamination and the spread of resistant bacteria.