Bakground and objectives: "The comb antibiotic sensitivity test" is a quick, reliable and cost effective method to determine the susceptibility of bacteria to different antibiotics. The purpose of this study is to design a plate that is easy and quick to use, and enable to be interpreted easily without the need for measurement of the margins with a ruler.Material and Methods: First, Clinical and Laboratory Standards Institute data about the maximum growth inhibitory haloes formed with antibiotics and various MICro-organisms were statistically examined and determined that the most (99.7%) zone of inhibition growth is formed in the range of 42 mm. Accordingly, the obtained number (42 mm) and conventional plate size (100 mm) used for testing sensitivity were punched into Solid works software which was used to determine the best place of strip and shoulder plates. After that the efficacy this media were examined by determination of MIC Staphylococcus aureus and Klebsiella pneumonia, non-graded and graded plate shoulders were searched and compared.Results: Has been placed two combs MIC in a plate in this method and didn’t create growth inhibitory haloes interferences. Obtained MIC for Nitrofurantoin (10 µg/ml), Amikacin (0.5 µg/ml), GentaMICin (1 µg/ml), and Amoxicillin (0.5 µg/ml) against S.aureus, MIC Nalidicsic Acid, Amikcin, GentaMICin and Nitrofurantoin against K.pneumonia was 0.1, 0.5, 0.5 and 10 µg/ml, respectively.Conclusion: The comparison between this new innovative method and standard methods (Clinical Laboratory Standards Institute-CLSI) shows that there a marked reduction in the interference of antibiotic therapy and will also reduce time of interpretation.

Background: Cefepime was used as empirical treatment in ventilator-associated pneumonia (VAP) induced by gram-negative and gram-positive bacteria. This study aimed to determine the antiMICrobial susceptibility pattern of cefepime against MICroorganism causing VAP in Mazandaran, North of Iran.Methods: This study was performed on VAP patients diagnosed with clinical pulmonary infection score (CPIS) scores in ICU of two hospitals. For each patient suspected of having VAP, quantitative culture of endotracheal aspiration (QEA) was performed and MIC was determined by MICro dilution test. Data were collected and analyzed.Results: Thirty- five cases of enterobacteriaceae were isolated orderly including E coli 13, P. aeruginosa 11, Enterobacter 7 and K. pneumonia 4 cases. All the isolated E. coli, Enterobacter and Klebsiella, 54.5% of P. aeruginosa isolated were fully resistant to cefepime.Conclusion: The results of this study show that cefepime is not a reasonable choice for empirical treatment of nosocomial pneumonia and VAP.

Streptococcus pneumoniae continues to be a leading cause of morbidity and mortality in persons of all ages. For sensitive strains of pneumococci, penicillin remains the drug of choice for pneumococcal infections. Penicillin resistance occurred soon after the discovery of penicillin. Pneumococcal resistance is now distributed globally. In many countries, penicillin resistance in pneumococci is increasing. Our study carried out over 90 pneumococci isolates from 1997-1998 in Mashad with using MIC method nab agarie diffusion.The prevalance of pencillin susceptible, intermediate resistance and high resistance were 0%, 62.2% and 37.8% respectively. Results of our study denotes that pencillin cannot .be considered as an effective first line antibiotic at least for serious pneumococcal infections in Mashad. As a consequence, a switch of therapy from penicillin to other agents is mandatory in infections caused by penicillin resistant strains.

Background: Shigella dysenteriae causes one of the most acute kinds of diarrhea which could be established as chronic infection with alternative periods of recurrence. Administration of normal doses of antibiotics will suppress MICrobial infections; however it is possible to control these infections by consumption of sub-MIC doses of certain antibiotics.Materials and methods: In this basic study, a strain of Shigella dysenteriae (PTCC: 1188) was used. After determination of MIC by MICrodilution method in Muller-Hinton Broth and MBC in Muller-Hinton Agar, the different dilutions (1/2, 1/4, 1/8) of MIC were prepared in order to study the sub-MIC effects of ciprofloxacin on some traits of Shigella dysenteriae.Results: The results showed that different sub-MIC dilutions of ciprofloxacin could cause morphological changes in Shigella. The Shigella cells became filamentous in 1/2 MIC whereas this configuration was weaker in 1/4 MIC and 1/8 MIC. Meanwhile, the appearance of colonies was changed significantly due to the higher concentrations of sub-MIC. Some of the biocheMICal traits were affected by sub-inhibitory concentrations of ciprofloxacin.Conclusion: Ciprofloxacin is a drug of choice for shigellosis. According to the results of this study, treatment of Shigella infections would be possible by lower doses of ciprofloxacin.

Background: Bacterial meningitis is one of the most serious infections in infants and children. Three organisms include S.Pneumo;N.mening;H.Influ are the most common cause of meningitis in children between 2M-14y age. Etest is a new method for determination the MIC of some antiMICrobial drugs in agarose .This method is useful for some organisms like as S .Pneumo; N.mening; H.Influ;sensitive Streptococcus and anaerobic ;aerobic gram negative.Materials and Methods: In this descriptive cross sectional study; In 57 suspected meningitis children ; organisms isolated from blood; CSF or other sterile boy fluid after culturing and antibiogram;. .MIC of someorganisms detected by Etest method.Results: Streptococcuswas the most prevalent ( 70%) and S.pneumon( 90% of all Streptococcus); H.infl 2%;N.mening 4%and L.monocyt 6%(more than expected);Gram negative (Ecoli; Klebsiella; entrobacter and psudomona) 18%. There was significant difference (P =0.01)in type of organisms between age groups. S.pneumonia was more frequent in children > 2 year ;N.meningitis in>4yr old .Site of isolation :blood; CSF (35.8*;28.3%)other sterile site 18.4%;concomitant positive culture in two site:17%.Mean age in Streptococcus was significantly different with Listeria (p=0.05); N.meningitis (p=0.04);H.influ (p=0.04);.but no difference with Staphylococcus; Klebsiella and E.coli Two type of H.inf were sensitive to Ampici or chloram ;both of them were sensitive to ceftiaxon. GBS were sensitive to PNC or AmpiciStrep.nonAnonBnon-Cotrimoxazol>32MIC/ml /PNC >256MIC/ml/ Vanco>256MIC/ml Strep.D:Cotrimoxazol>0.062mg/ml/ /PNC >0.016MIC/ml/Imipenem>0.032MIC/ml.Strep Pneumonia:All fo them were sensitive except 3 cases/Cotrimoxazol>2ic/ml /PNC =0.01MIC/ml/Vanco>0.125MIC/ mVanco>0. 25MIC/ ml/.Cotrimoxazol>2ic/ml / PNC =0.01mg/mlVanco>0.125MIC/ ml / Cotrimoxazol>2MIC/ml /MIC-PNC >0.016MIC/ml Therefore high dose of PNC is adequate for S.pneu ;because of Interm resistance to PNCAll 3 N.menin were sensitive to PNC;Chlora;Ceftria and vancoResistant to all drugs and high MIC for cefotaxime;CIPRO>32MIC/ml. E coli: Pseudomona Aerogenosa::Ceftriaxon>256MIC/ml/ /Genta>0.038mg/mlImipenem>32MIC/ml.Klebsiella; only Sensitive to CiproStaph .Aureous:Sensitive to Clinda;Cipro;Chlora;Resistant toCeft;PNCand CotriConclusion: Most type of N.meningitidis;H.inf and S.pneumonia were sensitive to many drugs. Only minority of them were resistant to Ampicillin but sensitive to chloramphenicol and vice versa. limited number of pneumococcal resistance to penicillin is medium resistance( MIC:0.1-1) .we can treat this resistant type by increasing of penicillin dosage .The others were sensitive to all drugs. Therefore ampicillin and chloramphenicol are the drug of choice in empiric treatment of bacterial meningitis after neonatal period.

Introduction: Malva sylvestris belongs to Malvaceae family from which A great deal of (malvone A: 2- methony-5, 6di hydroxyl-1, 4naphthoquinone) anthocyanins and important natural pigments have been extracted. Anthocyanins and other substances of Malva sylvestris own antibacterial properties.Methods: In this study, antibacterial properties of Malva sylvestris were investigated on the 6 bacterial species (Pasteurella multosida, Listeria monocytogenes, Salmonella enterica, Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae) via Hydro-alcoholic extract (arial and root organs) Results: In this study, the anti-bacterial effects of alcoholic extract of Malva sylvestris was separately investigated according to which the most ani-bacterial effect belonged to the extract of the aerial parts on Pasteurella multosida (3.12 (0.19mg/ml) %) and no effect was observed on Salmonella enteritidis.Conclusion: however antibiotics play an important role in human health, with the increasing occurrence of bacterial resistance against available antibiotics, it has now become essential to look for newer antibiotics.

Background: Application of natural compounds, including essential oils (EOs) and lysozyme is an effective method against growth of bacterial pathogens in foods.Objective: Determination of minimum inhibitory concentration (MIC) of lysozyme and Zataria multiflora Boiss. essential oil on L. monocytogenes.Methods: In this study different concentrations of lysozyme and Zataria multiflora Boiss. EOwere used alone and in combination on BHI broth to determine MIC of Zataria multiflora Boiss. EO and lysozyme with macro dilution and MICro dilution methods and effect of sub inhibitory concentrations of them on bacterial growth curve of L. monocytogenes.Results: The minimum inhibitory concentration (MIC) of Z. multiflora Boiss EO was estimated %0.04 using macro and MICrodilution. lysozyme at the highest concentration (1000 mg/ ml) was not effective in inhibition of bacterial growth and no MIC value obtained. Combination of EO and Lysozyme decreased the MIC value to %0.02 and 250 mg/ mlfor Z. multiflora Boiss. EO and lysozyme, respectively. The results of growth curve analysis showed that combination was effective in increasing the lag phase.Conclusion: Z. multiflora Boiss and lysozyme showed to be effective against bacterial growth and its potential application in food systems may be suggested.