Characterization of Multidrug Antibiotics Resistant Strains from Soil Samples

The spread of antibiotic residues increases the burden of antibiotic resistance microorganisms. The purpose of this study was to determine the antibiotic resistance pattern in isolated bacteria from Isfahan soils. The soil samples collected from agricultural lands (19 samples) and non-agricultural (industrial) (16 samples). The resistant bacterial population was determined using five antibiotics including erythromycin, vancomycin, and co-trimoxazole (0.5 mg/L), gentamicin (1 mg/L) and, penicillin G (2mg/L) and identified by standard cultural, morphological and biochemical characteristics. Antibiotic susceptibility of the isolates determined by minimum inhibitory concentration (MIC) by macro broth dilution. Subsequently, minimum bactericidal concentration (MBC) and multiple antibiotic resistance (MAR) profiles were determined. A total of 152 bacteria from different genera such as Staphylococcus, Corynebacterium and Bacillus sp were determined. The incidence of gentamicin and erythromycin-resistant bacteria were highest in agricultural and industrial soils, respectively. The MIC and MBC concentration of penicillin G were significantly higher than other antibiotics. Results revealed that 84% of isolates were MAR which half of them were tetra and penta-resistance to antibiotics. Many factors such as the Zayanderud River and using of livestock is affected by bacterial resistance in soil and water.