Zakieh Seifoori - Department of Microbiology, Islamic Azad University, Kerman Branch, Kerman, Iran
Nadia Kazemi Pour - Department of Microbiology, Islamic Azad University, Kerman Branch, Kerman, Iran

Introduction and Objectives: Upper respiratory tract infection is one of the most common bacterial infections in humans and the second reason for the high administration of antibiotics. The upward trend of antibiotic resistance in bacterial pathogens is a worldwide challenge. Materials and Methods: In this study, the upper respiratory tract samples of patients were evaluated during a three-month period from February 2019 to April 2019. Respiratory specimens were cultured on blood agar and nutrient agar media. The bacteria were grown on the plates then identified by conventional biochemical tests. The disc diffusion antibiotic susceptibility test was performed according to CLSI standards to 5 antibiotics. In addition, the minimum inhibitory concentration was done by broth macro dilution method for antibiotic resistant isolates about gentamicin antibiotic Next, the percentage of cell surface hydrophobicity for 13 strains was determined.5 isolated with the highest and lowest hydrophobicity were selected and used to study biofilm formation on glass, polypropylene surface with stable and shake condition. Results: 59 bacterial isolates with positive respiratory culture, were respectively including: 37.28% Staphylococcus spp.,20.33% Klebsiella spp.,16.94% Pseudomonas spp.,6.77% Escherichia Coli ,5.08%Streptococcus spp., and Citrobacter spp. Serratia spp. Proteus Spp. Corynebacterium Spp.3. 38%. Antibiotic susceptibility test for isolated showed maximum resistance to tetracycline and most of isolates sensitive to gentamicin. The MIC test showed that mostly of isolated were sensitive to gentamicin. The results of biofilm production on the selected surface, was indicate increasing the biofilm formation on propylene surfaces and in shaker condition. Conclusion: According to the results, there is a direct relationship between antibiotic resistance and biofilm formation potential in isolates. The incorrect prescription of antibiotics for treatment of this infection has increased the resistance of pathogens to antibiotics and also the production of biofilm. An effective program can be developed by evaluating antibiotics susceptibility patterns and new therapeutic methods.

Upper Respiratory Tract Infection, Bacteria, Antibiotic Resistance, Biofilm