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Introduction: Extracts of leaves from Camellia sinensis L contains polyphenolic components with antimicrobial activity. In this investigation biofilm inhibitory effects of black and green tea extracts were defined for five members of enterobacteriacea family including: Enteropathogenic Escherichia coli, Shigella flexneri, Proteus mirabilis, Klebsiella pneumoniae and Salmonella enterica serovar Typhimurium. Because tea is the most widely drunk beverage in Iran, therefore investigation of its effects on enterobacterial biofilm formation and colonization is very important. Materials and Methods: In this experimental study after extraction of samples with Soxhlet extractor in water/ methanol solution, further extraction took place in Ethyl acetate phase. The extracts preserved in 4oC refrigerator after sterilization by 0.44 µ filters. Well diffusion (Kirby Bauer) and broth dilution methods were used for evaluation of minimum inhibitory concentration of biofilm formation in black and green tea extracts treated cultures. Evaluation of biofilm formation was assayed by observation of colony forming unit of cultured bacteria per milliliter by sampling from Erlenmeyer flask wall scratching onto Tripticase soy agar medium and comparing the results with controls. Analysis of data was done using analysis of variance. Results: Biofilm inhibitory effects of black tea were greater than green tea. The concentration of 4.5 mg/ml of black tea and 5mg/ml of green tea had bactericidal effects against examined bacteria. On Mueller Hinton agar, Proteus mirabilis was more sensitive to black tea EPEC was more sensitive to green tea and Klebsiella pneumoniae showed more resistance to both extracts. Conclusion: Due to the fact that gastrointestinal tract is directly affected with consumed beverage, the high concentration of tea entered in lumen can reduce the number of enterobacteriaceae and can reduce their carcinogenic amine products. Thus it plays an important role in inhibition of gastrointestinal lymphoma and colon carcinoma. Also application of tea polyphenols as a food preservative can be useful.

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Background: Candida albicans is the fourth common cause of chronic fungal infections that cause both mucosal and deep tissue infections. Nowadays, mortality and morbidity due to C .albicans infections via medical devices, such as catheter and implants, are increasing. Therefore, finding new methods of combating such infectious agents seems necessary. In this study antifungal effects of titanium dioxide nanoparticles and photocatalyst TiO2 nanoparticles on C .albicans biofilms were investigated. Materials and Methods: In this experimental study, TiO2 nanoparticles were synthesized and exposed to UV ray with 370 nm wavelength. Biofilms of C. albicans were developed on flat-bottomed 96-well microtiter plates, and antifungal effects of TiO2 and photocatalyst TiO2 nanoparticles were evaluated. Data were analyzed by t-test using SPSS software. Results: MIC50 of photocatalyst TiO2 nanoparticles was 1.9 µg/ml and its MIC90 was 2.74 µg/ml while MFC was determined to be 3.37 µg/ml. Biofilms inhibitory concentration of TiO2 nanoparticles, photocatalyst TiO2 nanoparticles, and fluconazole for susceptible strains were 5.14, 4.54, and 4 µg/ml, respectively. These values for the fluconazole resistant strains were 5.35, 4.88, and 8 µg/ml, respectively. Conclusion: Photocatalyst TiO2 nanoparticles showed a suitable antifungal property against C. albicans biofilms compared with fluconazole. Thus it can be a new strategy in prevention of fungal biofilms, especially those formed on the surface of medical devices.

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Background: Numerous factors, such as Enterococcus antimicrobial resistance and expression of virulence factors, may account for the maintenance and prevalence of Enterococci infection. The aim of the present study was to assess the occurrence of esp and eep genes in the E.faecalis and E.facium strains isolated from the patients with urethral system infections. Materials and Methods: In this experimental study, 214 clinical samples, including 80 catheters and 134 urine samples, were collected from the patients. The identification of the isolated samples was based on the growth on Bilesculin agar culture media, tolerance of 6.5% Nacl, gram staining, and catalase, hydrolysis of hyporate, telorite reduction, arginine hydrolization, and fermentation of the carbohydrates tests. The assessment of genes was done by PCR method. Results: esp gene was present in 83% of the urine samples and in 97% of the catheters while eep gene was present in 100% of the urine samples and 90% of the urine catheters. The results of antibiogram indicated that the multi-antibiotic resistance was about 78.1% against vancomycin and tetracyclin, 75% against cyprofeloxin and tetracyclin, 59.3% against vancomycin and cyprofeloxin, and about 53% against vancomycin and streptomycin. Conclusion: The findings of this study indicate that esp gene plays an important role in formation of biofilm in patients. Due to the presence of eep gene in almost all of the samples, it can used as a rapid identical agent for the assessment of pheromone production and provision of suitable conditions for plasmid transformation between clinical strains and the prevalence of antibiotic resistance.

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Background: Biofilm formation is one of the pathogenicity factors of Staphylococcus aureus that can help the bacteria to stick to the other surface and also increase antibiotic resistance pattern. This study aimed to investigate the phenotypic and genotypic indices for formating biofilm in Staphylococcus aureus isolates isolated from infectous samples.

Materials and Methods: 250 Staphylococcus aureus strains isolated from hospital infections were selected. Antibiotic resistance pattern was determined by using disk diffusion method. The ability of biofilm formation was investigated by molecular and phenotypic method.

Results: In this study, 73.5% of isolates were able to bind strongly, 5.33% had the ability of medium connection and 15.4% had the ability of weak connection in biofilm production. The frequency of icaC and icaB genes were 67.3% and 63.2%, respectively. 92.2% of biofilm producing isolates have mecA gene.

Conclusion: The spread of antibiotic resistance in isolates especially isolates that produce biofilm will create serious problems in the hospital therapeutic wards.

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Background: In the recent years, introducing plant materials with the ability to destroy or control of biofilm formation of Streptococcus mutans is highly regarded.This study was planned to investigate the anti-bacterial activity and biofilm inhibition of Satureja Khuzestanica Jamzad against biofilm and single form of S.mutans.

Materials and Methods: The plant material collected, air dried and powdred. Then thier methanolic extract prepared by maceration method.The concentrated extract then diluted by sterile phosphate buffer.The anti-bacterial and biofilm inhibition activity of the extracts evaluated by dick diffiusion and micro titeration method respectively. Also, bioinformatic study of glucansucrase inhibition by dominant plant compounds of S.Khuzestanica Jamzad investigated by molecular docking method using Auto dock4 software.

Results: The results revalued that all tested extracts especially leaf ectract had significant antibacterial activity against single form of S.mutans.Results also showed that leaf and stem extract had most and least biofilm inhibition with 70 and 13 presend inhibition, respectively. The bioinformatics results also confirmed that studied phytochemicals especially gama-terpinen, carvacrol and beta-bisabolene can effectively inhibit the glucansucrase.

Conclusion: The results of present study showed that S.Khuzestanica Jamzad had significant antibacterial activity against single form of S.mutans and gama-terpinen, carvacrol and beta-bisabolene are most effective compounds in biofilm inhibition.

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Abstract

Background: Acinetobacters are aerobic gram-negative bacteria which are distributed widespread in soil and water. The bacteria are isolated from cultured skin, mucous membranes, secretions and hospital environment. Acinetobacter baumannii, is a strain that more frequently isolated. Acinetobacter strains are often resistant against antimicrobial agents.

Materials and Methods: The method of this study was based on field, observation and test. On August and October 2015, samples were isolated from the soil and water of the Sadeghieh Square river in Tehran, respectively, and were transferred to the laboratory in the ice pack. 50 baumannii samples were isolated by biochemical methods (TSI, SIM, OF and gram test). November 1394, 100 clinical samples were isolated from Imam Khomeini hospital by biochemical method, and in the culture media Mueller Hinton agar plates were transferred to the laboratory. Antibiogram test for 150 baumannii samples was performed. Biofilms formation of Acinetobacter baumannii environmental and clinical samples was investigated by Congo red agar and culture plate methods.

Results: In all samples (clinical and soil), most of antibiotic resistance was 92% for imipenem and the resistance of water samples to imipenem was 99.9%. Biofilm formation by Congo red agar in water, soil, and clinical samles was resprctively 44%, 40% and 1%. All isolates were negative biofilm culture plate.

Conclusion: Considering Acinetobacter baumannii resistance to antibiotics and the lack of biofilm formation of in clinical and environmental isolates, it was concluded that there wasn’t any relationship between antibiotic resistance and biofilm formation.

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