The occurrence of antibiotics in the natural environment has been a growing issue and correlations between this presence and developing resistance bacteria are explored. The purpose of this study was to investigate the presence of antibiotics of different classes and associated resistant bacteria, in water samples taken from urban river waters in Curitiba, Brazil. A method for the quantification of antibiotics (azithromycin, amoxicillin, norfloxacin ciprofloxacin, doxycycline and sulfamethoxazole) was developed and validated using liquid chromatography coupled with mass spectrometry. To investigate and identify coliforms resistant to these antibiotics, we performed selective microbiological culturing techniques. We detected antibiotics in our water samples; concentrations ranged from 0.13 to 4.63 μg L⁻¹, with the highest being amoxicillin at 4.63 μg L^-1. In all water samples this study, antibiotic resistant bacteria were detected. Escherichia coli was resistant to amoxicillin, norfloxacin, ciprofloxacin, doxycycline and sulfamethoxazole. Strains producing β-lactamase with extended spectrum (ESBL and AmpC) were also found in these isolates. Enterococcus spp. displayed resistance to norfloxacin and ciprofloxacin, and some isolates were resistant to vancomycin, gentamicin and streptomycin (complementary tests). No P. aeruginosa resistant strains were observed. It is possible these antibiotics came from domestic effluents and may be contributing to the spread of bacterial resistance

在自然环境中，抗生素的存在已成为一个日益严重的问题，并探索了这种存在与正在发展的抗药性细菌之间的相关性。这项研究的目的是调查从巴西库里提巴城市河水中采集的水样中不同类别的抗生素和相关耐药菌的存在。建立了一种定量分析抗生素（阿奇霉素，阿莫西林，诺氟沙星，环丙沙星，多西环素和磺胺甲恶唑）的方法，并通过液相色谱与质谱联用进行了验证。为了研究和鉴定对这些抗生素具有抗性的大肠菌群，我们进行了选择性微生物培养技术。我们在水样中检测到了抗生素；浓度范围从0.13至4.63μgL ^-1，最高的是阿莫西林，为4.63μgL ^-1。在这项研究的所有水样中，均检测到抗生素抗性细菌。大肠杆菌对阿莫西林，诺氟沙星，环丙沙星，强力霉素和磺胺甲恶唑具有抗性。在这些分离物中还发现了产生具有扩展光谱的β-内酰胺酶的菌株（ESBL和AmpC）。肠球菌。表现出对诺氟沙星和环丙沙星的耐药性，一些分离株对万古霉素，庆大霉素和链霉素耐药（补充试验）。没有观察到铜绿假单胞菌抗性菌株。这些抗生素可能来自生活污水，可能有助于细菌耐药性的传播