Detection of Antibiotic-resistant Escherichia coli in the Euphrates River, Iraq

Abstract

Water plays a crucial role in the spread of antibiotic-resistant bacteria (ARB) among humans, animals, and the environment. The emergence of antibiotic resistance is a global health and environmental problem. This study aimed to identify the temporal and spatial patterns and hotspots of antibiotic-resistant Escherichia coli (AREs) in the Euphrates River in central Iraq. Integrating Escherichia coli (E. coli) testing with key environmental parameters allowed for linking resistant bacteria to pollution sources. Water samples were collected from four selected points along the river during the dry and wet seasons of 2023 and 2024. Fecal samples (non-environmental samples) were also collected from areas surrounding the river to study their impact on it. Resistance patterns of E. coli and multidrug resistance to 12 antibiotics of 11 rows were tested for 80 river water isolates and 39 non-environmental isolates by using methodological methods. E. coli showed the highest resistance to ampicillin (97.5%), followed by cefotaxime (96.25%). Importantly, multidrug resistance was recorded in 93.75% and 97.44%, of river and non-environmental isolates, respectively. The recorded values for the Antibiotic Resistance Index exceeded the threshold. Environmental parameters showed varying degrees of association with antibiotic resistance. There are few reports about ARB in Iraqi rivers due to the focus on clinical samples. Nevertheless, a full understanding of the origin, spread, and persistence of antibiotic resistance requires an integrative strategy that considers all ecosystems that may contribute to its spread. Our findings demonstrate the urgent need to address fecal contamination and the spread of ARB in Iraqi rivers.