Assessment of Antibiotic Resistance in Waterborne Pathogens

Abstract

This study aimed to assess the antibiotic susceptibility of bacterial isolates from raw water samples using the broth microdilution method. The tested antibiotics demonstrated inhibitory effects on bacterial growth. MIC values ranged from <0.25–7.81 μg/mL for tetracycline, 0.98–62.25 μg/mL for ampicillin, and <0.001–0.25 μg/mL for ciprofloxacin. The findings revealed that while most isolates were susceptible to the tested antibiotics, resistance was detected in specific strains. Escherichia coli V9 and Enterobacter cloacae V7 exhibited resistance to tetracycline, while Citrobacter braakii V1 and Raoultella ornithinolytica V4, V5, and V10 were resistant to ampicillin. All tested isolates remained susceptible to ciprofloxacin. Additionally, Acinetobacter spp. and Aeromonas spp. were intrinsically resistant to ampicillin, consistent with established resistance patterns. These findings reveal antibiotic-resistant bacteria in raw water, underscoring environmental risks and the need for ongoing research to curb resistance spread and protect public health.