Introduction: Although bacteria producing biofilm are more resistance to antimicrobial agents, biofilm formation can stimulated by sub-MINIMAL INHIBITORY CONCENTRATIONS (sub-MICs) of some antimicrobial agents. Therefore, we designed present study to investigate the in vitro efficacy of several antibiotics (including ceftazidime, piperacillin, ticarcillin, carbenicillin, aztreonam, meropenem, gentamicin, amikacin and ciprofloxacin) and biocides (including savlon, benzalkonium chloride and chlorohexidin) on biofilm formation in Pseudomonas aeruginosa (P. aeruginosa) isolates.Materials and methods: A total of 10 uropathogenic P. aeruginosa isolates were collected from Mostafa Khomaini Hospital in Ilam. The isolates were evaluated for MIC, biofilm formation ability and finally the effect of different concentration of antimicrobial agents on the biofilm formation.Results: Our finding demonstrated that all antimicrobial agents except gentamicin, aztreonam, and savlon were able to induce biofilm formation at sub-MICs. Moreover, savlon was the best agents for encountering biofilm formation in P. aeruginosa.Conclusion: Some antimicrobial agents are able to induce biofilm formation at sub-MICs. Biofilm formation inducement depended on antimicrobial agents, strains, and matrix composition.

Background: L- forms of S. aureus are cell wall -defective bacteria that grow and multiply in hypertonic media. Vancomycin is an effective antibiotic for remedy of staphylococcal infections an important inducer of L-forms. The present study investigated whether staphylococcal L-forms induction is related to concentration of vancomycin and whether these forms are stable in blood or not.Materials and methods: In this study, effect of different CONCENTRATIONS of vancomycin on standard strain of S.aureus (ATCC 25923) were tested; Then growth of bacteria in four media (BHI Agar, BHI broth, LPM Agar and LPM broth) were studied. After induction of L-forms in LPM broth, these forms were injected to human complete blood.Results: In bactericidal and MINIMAL INHIBITORY CONCENTRATIONS of vancomycin, no growth of bacteria in three media was observed, but growth of bacteria in LPM broth after 72 hours was observed. Injection of S.aureus L - forms in to human blood caused changes of these forms to natural bacteria.Conclusions: The results confirm that use of one cell wall affecting Antibiotic alone for remedy of staphylococcal infections, may increase the risk of induction of L - forms and drug resistant bacteria.

Background: Phototherapy is an important modality in dermatology and the number of skin diseases which can be controlled with it IS mcreasmg. In order to start treatment, the first dose of phototherapy is determined by measurement of MINIMAL erythema dose (MED) in each patient individually or according to patient"s skin type. Objective: To determine the relationship of skin type with MED in patients under UV phototherapy referred to Razi Hospital in Tehran Patients and Methods: In patients referred to Razi Hospital in 1381(2002-2003) for UVB phototherapy, skin type was determined according to Fitzpatrick"s classification and MED was measured using a UV-meter. Age, sex and the disease of the patients were also recorded. The data were analysed using one way ANOVA and Welch tests. Results: Eighty patients including 39 males and 41 females were studied. The mean age of the patients was 32 years (SD=15.8). Their diseases include psonasls, vitiligo, parapsoriasis, pityriasis lichenoides chronica, perforating disorder and patch stage mycosis fungoides. The mean of MED in 17patients with skin type Il was 111.8±39.2, in 42 patients with skin type III was 105.9±43.1 and in 21 patients with skin type IV was l14.3±39.2 mJ/cm2 , with no significant statistical difference. Conclusion: The first dose of phototherapy could not be determined based on skin type and measurement of MED is necessary in each patient.

We define MINIMAL CN-dominating graph MCN (G), commonality MINIMAL CN-dominating graph CMCN (G) and vertex MINIMAL CN-dominating graph M vCN (G), characterizations are given for graph G for which the newly defined graphs are connected. Further serval new results are developed relating to these graphs.

Background: A surgical site infection (SSI) is the most common nosocomial infection after surgery and is the third most common infection in hospitalized patients. The aim of this study was to asses minimum INHIBITORY concentration (MIC) of the causing agents of SSI and antimicrobial susceptibility patterns.Methods: This cross sectional study was done in three referral hospitals in North of Iran during 2011-2012. The samples were taken one month after orthopedic, abdominal, cesarean section surgery and coronary artery bypass graft (CABG) in patients with scores compatible to SSIs criteria. The sample was sent for bacteriologic culture and MIC determination for positive cases by broth microdilution method. The data were collected and analyzed.Results: From 103 positive cases S. aureus, E.coli and coagulase negative staphylococci were the most common isolated agents as 29.12%, 23.3% and 21.3%, respectively. S. aureus was sensitive to vancomycin (70%), amikacin (70%) and teicoplanin (76.6%) and cogulase negative staphylococci was sensitive to vancomycin (68.1%) and teicoplanin (72.6%) and E.coli to amikacin (95.83%) and imipenem and meropenem (66.66%). P.aeroginosa showed no sensitivity to cefepime and was sensitive to imipenem (93.75%) and meropenem (81.25%).Conclusion: The most important point is worrisome problem of the increased MIC of S. aureus to vancomycin that causes difficult use in the treatment of staphylococcal SSIs. In spite of resistance of micro-organisms to cephalosporins, gram negative organisms had low MIC to carbapenemes especially P.aeroginosa although the rate of its MIC is increasing.

Minimum INHIBITORY CONCENTRATIONS (MIC) of some essential oils and citric acid were determined against two micro-organisms associated with spoilage of orange juice (Saccharomyces cervisiae and Leuconostoc mesenteroids) and against four unidentified microorganisms isolated from citrus surface and spoiled orange juice. MIC for limonene were obtained less than 5% w/v aqueous against Saccharomyces cervisiae and Iso-2.Lianalool minimum INHIBITORY CONCENTRATIONS was less than 5% w/v aqueous for Leuconostoc mesenteroids. MIC for other microorganisms and essential oils and citric acid were determined more than 5 % w/v aqueous. Survivor Curve testing was conducted on 6 microorganisms.

Bioethanol made from lignocelluloses biomass resources, provides unique environmental, economic and strategic benefits, when compared to gasoline as automobile fuel. To be able to substitute gasoline by bioethanol, one should over come many obstacles, including the production of furfural and hydroxyl-methyl furfural, which are produced when cellulosic materials are treated in the presence of acids in high temperature and pressure to produce simple sugars. These INHIBITORY compounds have a profound negative effect on the growth of ethanol producing yeasts and their ethanol production. Saccharomyces cerevisiae Lalvin EC1118™, an industrial ethanologenic strain, was used in media with high CONCENTRATIONS of furfural (i.e. 4, 5 and 6 g/L) to study the tolerance it shows against this compound. Results showed that both the amount of growth and ethanol production were decreased when furfural was present in the media. The amount of decrease was higher in the concentration of 6 g/L of furfural than 4 and 5 g/L.

Recently, plant pathogen’s biocontrol is a priority considering hazards and environmental threats of chemical pesticides. Using plant materials as antimicrobes has typically attracted many attentions. The aim of current study was evaluation of plant materials obtained from purple coneflower against Pectobacteriumcaratovorum subsp. caratovorum the casual agent of potato soft rot. Aqueous, acetone, methanol, ethanol and HCl extracts of coneflower root, stem, leaf and flower were obtained byrotary set while flower essential oils were extracted using Clevenger apparatus. The antimicrobial activity of coneflower extracts and essential oil was evaluated in laboratory with disc diffusion and MINIMAL INHIBITORY and bactericidal concentration methods. The bacterium was more sensitive to flower essential oil than extracts. Root extracts were more INHIBITORY compared with other organs’ extracts. Also, aqueous and acetone extracts had very limited antibacterial activities on studied bacterium. Leaf extract possessed more growth inhibitor characteristic rather than bactericide traits. Regarding the results, plant materials obtained from coneflower could be a potent candidate against potato soft rot bacterium and might be considered as a promising biocontrol agent in the future.

Background and Aim: Staphylococcus aureus (S.aureus) is one of the most prevalent causes of nosocomial infections. It is also involved in community acquired infections. The resistance of this bacterium towards methicillin which has been reported since 1961, made Vancomycin the last choice for treatment of Staphylococcal infections.Considering the reduced sensitivity or resistance to vancomycin which has been observed since 1996, this study was conducted with the aim of evaluating the vancomycin MIC values (Minimun INHIBITORY Concentration) of S. aureus cells isolated from hospitalized patients and compared with those recovered from outpatients.Materials and Methods: A cross sectional - analytic survey was conducted from 2006 till 2007. A total of 200 S.aureus strains were isolated from various clinical sources including blood, sputum, urine and sinus secretions. Their susceptibilities to vancomycin were initially surveyed by disk diffusion method. Subsequently, the MIC values of each individual strain towards vancomycin were determined by E-test strips, and the obtained data was analyzed by SPSS (V. 11) software. For statistical analysis, t-test was used.Results: In 125 S. aureus strains isolated from hospitalized patients, the growth inhibition zones were 14-18 mm and the MIC values were 1-2 mg/ml. In 75 S. aureus strains isolated from outpatients, the growth inhibition zones were 16-20 mm and the MIC values were 0.75-1.5 mg/ml.Conclusion: The result of this survey shows increased MIC values for vancomycin in hospitalized patients as compared to outpatients.

Background: Today with raised use of antibiotics and prevalence of resistant strains, there is need for antimicrobial drugs that have fewer side effects than antibiotics. Rosmarinus officinalis is a medicinal plant which had many uses in traditional medicine. In this study, methanol leave extract of this plant is tested on various pathogens.Materials and Methods: In this in vitro study Rosmarinus officinalis was used to evaluate its antimicrobial effects. Methanol leave extract of this plant with CONCENTRATIONS of 400, 200, 100, and 50 mg/ml were prepared, and antibacterial activities were evaluated by well diffusion method on strains of Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus and Staphylococcus aureus. Minimum INHIBITORY concentration and minimum bactericidal concentration were determined by the microplate method.Results: In this study, the most efficacy of thanol extract of rosemary leaves was at concentration of 400 mg/ml against Pseudomonas aeruginosa and Escherichia coli. Minimum INHIBITORY concentration of the extract on the growth of these bacteria showed changes from 6.25 mg/ml to 100 mg/ml. Also MBC of extract showed range from 12.5 to 200 mg/ml respectively.Conclusion: It was found that rosemary methanol extract inhibited growth of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa but did not inhibit of Bacillus cereus growth.