Microbiology
Zahra Yousefpour; Fateme Davarzani; Parviz Owlia
Abstract
Background & Objective: The ability of Pseudomonas aeruginosa to form biofilm has an important role in establishment of chronic phase of infections. Biofilm formation can be affected by antibiotics sub-MIC concentrations. The principal aim of the present study was to evaluate the effect of gentamicin ...
Read More
Background & Objective: The ability of Pseudomonas aeruginosa to form biofilm has an important role in establishment of chronic phase of infections. Biofilm formation can be affected by antibiotics sub-MIC concentrations. The principal aim of the present study was to evaluate the effect of gentamicin at sub-MIC concentrations on biofilm formation in 100 Pseudomonas aeruginosa clinical isolates.Methods: Determination of minimal inhibitory concentration of gentamicin for clinical isolates was done using micro broth dilution method. The amount of biofilm formation in the treated and untreated isolates with gentamicin sub-MIC (1/2&1/4MIC) concentrations was evaluated using microtitre plate assay. pelA and pslA genes were detected in clinical isolates by PCR method.Results: 99% of clinical isolates were biofilm producer. Different changes in amountof biofilm formation were observed in the treated clinical isolates with sub-MIC concentrations of gentamicin. Two dominant changes were observed in 80% of clinical isolates. These concentrations had inhibitory effect on biofilm formation in 46.4% of isolates and caused a significant decrease in its amount. While in 31.3% of the isolates, the biofilm formation was significantly increased. The frequency of pelA and pslA genes among clinical isolates was 100%. Conclusion: gentamicin sub-MIC concentrations cause different changes on biofilm formation of Pseudomonas aeruginosa clinical isolates. Therefore, further studies are needed for discovering new treatment strategies and using sub-MIC concentrations of the antibiotic in prevention and treatment of Pseudomonas aeruginosa infections.
Mohsen Mirzaee; Shahin Najar Peerayeh; Abdol-Majid Ghasemian
Volume 9, Issue 4 , October 2014, , Pages 257-262
Abstract
Background & Objectives: Methicillin resistance Staphylococcus aureus (MRSA) is one of the most important pathogens that causes several nosocomial and community infections. Adhesion to surfaces and biofilm formation is considered main step in staphylococcal infection. The aims of this study ...
Read More
Background & Objectives: Methicillin resistance Staphylococcus aureus (MRSA) is one of the most important pathogens that causes several nosocomial and community infections. Adhesion to surfaces and biofilm formation is considered main step in staphylococcal infection. The aims of this study were to determine presence oficaABCD genes and relation to the biofilm formation in of MRSA isolates. Methods: Of the 63 MRSA clinical isolates collected from selected hospitals in Tehran, Iran,quantitative biofilm formation was determined by microtiter tissue culture plates (MtP). All MRSA isolates were examined for determination the icaABCD genes by using PCR method. Results: twenty nine (46%) of the isolates were strong produced biofilm on Mtp. All of the MRSA isolates carried icaD and icaC genes, whereas, the prevalence of icaA and icaB was 60.3% and 51% respectively. Conclusions: S. aureus clinical isolates have different capacity to production biofilm and adhesion. This may be caused by a different in the expression of biofilm genes and hetrogenicity in genetic origins.
