Antibiotic resistance and biofilm formation of Pseudomonas strains isolated from patients with respiratory tract infections in Kerman hospitals, Iran

Background and Aim : Pseudomonas is one of the most common pathogenic bacteria in pulmonary infections and frequently develops resistance to different antibiotics. Accordingly, the aim of this research was to investigate antibiotic resistance and biofilm formation of Pseudomonas strains isolated from respiratory tract infections of hospitalized patients in Kerman, Iran.Methods : In this study, ۸۹ samples were obtained from patients and identified by biochemical methods during ۲۰۱۹. Antiboigram test with eight antibiotics was performed by disk diffusion method. Hydrophobicity of the bacteria was investigated by xylene for biofilm analysis. Selected bacteria with biofilm formation were examined on glass and plastic surfaces under static and shaking conditions.Results : Twenty Pseudomonas were isolated with the highest resistance to Carbenicillin (۷۶%) and the lowest antibiotic resistance to gentamicin (۳۲%). Minimum inhibitory concentration of the Gentamicin was observed in concentrations of ۲ to ۴ micrograms/ml ۵ (۲۸%), and for the same concentrations for amikacin ۱ (۴%). For the biofilm test, two bacteria with hydrophobicity above ۷۰% and two bacteria with hydrophobicity below ۳۰% were evaluated. Accordingly, high hydrophobicity was directly related to biofilm production under shaking conditions. Resistant strains with high biofilm formation were also identified by PCR method.Conclusion : Overuse and self-administration of drugs during recent years have caused antibiotic resistant strains of Pseudomonas with high ability in biofilm formation, which can lead to deaths in immunocompromised patients. So, by similar researches, our information about antibiotic resistance and biofilm formation patterns of Pseudomonas strains should be upgraded for appropriate therapy.

Keywords:

Pseudomonas , MIC , Antibiotic resistance , Hydrophobicity , Biofilm formation