Prevalence, Antibiotic Resistance, and Biofilm Formation of Bacterial Species in Water Samples from Baghdad, Iraq

Abstract

Background: Our global health is seriously threatened by the emergence rapid spread of antibiotic resistance bacteria. The misuse of antibiotics has resulted in heightened selection pressure and the proliferation of multidrug-resistant pathogens, thereby diminishing the efficacy of treatments. Water sources serve as important reservoirs for the transmission of antibiotic-resistant bacteria. This study aimed to isolate and identify aquatic bacterial species from diverse sources in Baghdad, assess their antibiotic resistance profiles, and detect the biofilm formation of the most multidrug resistance bacterial species to find the relationship between slime layer production and resistance to antibiotics. Methodology: We conducted an analysis of bacterial species in water samples obtained from 80 varied locations between July 2023 and April 2024, employing chromogenic media, biochemical testing, and the API system. The antibiotic sensitivity test of the bacterial isolates was conducted using the Kirby-Bauer method for ten types of antibiotics from various groups, including (AMP, AMC, CTX, HLS, C, CIP, TR, K, AK and O. Biofilm production of the most resistance to the highest number of antibiotics bacteria was assessed using two methods: Congo red agar and adhesion to a smooth surface. Results: Findings indicate an isolation rate of 40 bacterial isolates, distributed among water samples as follows: 18 (45%) from rivers, 13 (32.5%) from stagnant water, 5 (12.5%) from turbid water, 4 (10%) from tank water, and none from tap water. The primary bacterial species include Escherichia coli isolates, Pseudomonas aeruginosa, Enterobacter, Klebsiella oxytoca, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter, and Salmonella. The most common bacterial species were E. coli and P. aeruginosa. The majority of isolates exhibited resistance to AMP, AMC, then HLS, K, AK, O, then CTX, C, TR, and CIP that has the lowest resistance percentage. The results indicate variability in slime layer production among the isolates, and E. coli, P. aeruginosa were high resistance to AMP and AMC. Conclusions: The findings reveal the existence of multiple bacterial species in Baghdad water, which show susceptibility to various antibiotics while exhibiting resistance to ampicillin, tetracycline, and kanamycin, and differ in their production of slime layers. The findings increase public health awareness of antibiotic resistance bacterial species and slime layer production load in aquatic environments.