Background: In this study antimicrobial effectiveness test was performed on eye-drops which had high microbial contaminations in hospital practice to find out whether their antimicrobial efficacies affect the magnitude of microbial contamination during their uses.Materials and Methods: Artificial tear, atropine sulfate, betamethasone, homatropine hydrobromide, phenylephrine hydrochloride, phenylephrine zinc, pilocarpine hydrochloride, tetracaine hydrochloride and tropicamide eye-drops were subjected to the United States Pharmacopeia (USP) and British Pharmacopeia (BP) antimicrobial preservative effectiveness tests.Results: The results of this study showed that eight out of the nine products met the BP 'B' and USP criteria. The preservative employed in phenylephrine zinc eye-drop did not possess adequate antimicrobial activity against P. aeruginosa. Other eye-drops showed appropriate reductions in bacterial viability after 6 hrs, 24 hrs and 7 days, but showed a very low bacterial recovery after 28 days which didn’t comply with the no recovery (NR) term of BP 'A' criteria. Since viable microbial counts were usually determined by plate count method, it seems that the term of NR should define an acceptable range. Conclusion: The results indicated that there is not a clear correlation between antimicrobial efficacy testing of eye-drops and the rate of their microbial contamination while are being used. Other factors such as hygienic practices of eye-drops, proper bottle design and training of patients could influence their microbial contaminations. Regulation of in-use efficacy testing of eye-drops which is influenced by the environment, the frequency and technique of use, might be essential.

Objectives: The purpose of the present study was to evaluate the antimicrobial effect of various sizes and concentrations of zinc oxide (ZnO) nanoparticles on Streptococcus mutans (S. mutans), Enterococcus faecalis (E. faecalis), Lactobacillus fermentum (L. fermentum), and Candida albicans (C. albicans). Materials and Methods: Solutions at the concentration of 10 μ g/ml were prepared using 20-nm, 40-nm, and 140-nm nano ZnO (nZnO) powder. The antimicrobial effect of nZnO was determined using the disk diffusion method. The inhibition zone (mm) was measured using a ruler. Data were analyzed by analysis of variance (ANOVA) and the Bonferroni correction. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of nZnO were determined using the broth microdilution method in Mueller-Hinton Agar (MHA) for S. mutans and E. faecalis, De Man, Rogosa, and Sharpe (MRS) agar, and Sabouraud Dextrose Agar (SDA). Results: The greatest inhibition zones were observed against S. mutans with 20-nm and 40-nm nZnO, while 140-nm nZnO formed the greatest inhibition zones against S. mutans and E. faecalis. The smallest inhibition zones were observed against C. albicans with the three nZnO particle sizes. The MICs for C. albicans with 40-nm and 140-nm particles and for L. fermentum with 140-nm particles were higher than 10 μ g/ml. A significant correlation was found between the particle size and the antibacterial activity against S. mutans (P=0. 00), L. fermentum, and E. faecalis (P<0. 02). Conclusion: The antimicrobial activity of nZnO increases with decreasing the particle size. The greatest antimicrobial effect was observed against S. mutans and E. faecalis. S. mutans is more sensitive to the changes in the particle size compared to other bacteria.

Background and Aim: Considering the search for an effective antimicrobial agent comparable to chlorhexidine (CHX), this study aimed to assess the antimicrobial effect of Punica granatum (P. granatum) hydroalcoholic extract on Streptococcus sobrinus (S. sobrinus), Streptococcus sanguinis (S. sanguinis) and Candida albicans (C. albicans), in comparison with CHX. Materials and Methods: In this in vitro study, the disc diffusion test was used to assess the antimicrobial activity of the extract by measuring the growth inhibition zones,while, the microdilution and macrodilution broth tests were applied to find the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract against the tested microorganisms. The MBC was measured using the blood agar or Mueller Hinton agar culture medium. The Sabouraud dextrose agar culture medium was used for C. albicans. Each test was repeated in triplicate, and data were analyzed by independent samples t-test and Mann-Whitney U test. Results: None of the tested microorganisms showed any resistance to the extract. CHX had the highest antimicrobial effect against all tested microorganisms. The MIC of the hydroalcoholic extract of P. granatum was 2. 5 mg/mL for S. sobrinus and S. sanguinis, and 5 mg/mL for C. albicans. Its MBC was 5 mg/mL for S. sobrinus and S. sanguinis, and 10 mg/mL for C. albicans. The mean diameter of the growth inhibition zone for S. sobrinus caused by CHX was significantly greater than that caused by P. granatum extract (Mann-Whitney U test, P=0. 043). The same result was obtained for S. sanguinis (Student sample t-test, P=0. 002), and C. albicans (Mann-Whitney U test, P=0. 046). Conclusion: The hydroalcoholic extract of P. granatum has bacteriostatic and bactericidal effects on S. sanguinis and S. sobrinus and antifungal effect on C. albicans comparable to CHX.

Background and Objectives: Endophytic fungi are believed to possess compounds as antibacterial agents. This study was designed to determine in vivo antibacterial activity of the crude extracts from Lasiodiplodia pseudotheobromae IBRL OS-64 against pathogenic bacteria. Materials and Methods: The qualitative and quantitative screenings were performed using agar plug and disk diffusion antimicrobial tests, respectively. Besides that, the MIC and MBC value of the extracts were determined using broth microdi-lution assay and morphological changes of the bacterial cells exposed to the extract were observed under Scanning Electron Microscope (SEM). Results: Agar plug diffusion assay revealed that V. parahaemolyticus ATCC 17802 and Exiguobacterium profundum IBRL MA6 were the most sensitive to the extract with the size of inhibition zones of 11 to ≤,20 mm. The MIC and MBC values of the extract varied depending on the test bacteria. Observation through SEM revealed that the bacterial cells exposed to the extract experienced severe damage such as irregular shape with crumpled and shrunken cells which led to cell death. Conclusion: The data suggest that the crude extracts of L. pseudotheobromae IBRL OS-64 exert antibacterial activity against test bacteria and principally affect the cell wall in growing pathogenic bacterial cells.

Background and Objective: Pseudomonas aeruginosa has become a frequent cause of nosocomial infections, particularly in intensive care units (ICUs). Many reports have documented high rates of resistance in this species to commonly-used broad-spectrum antibiotics. The aim of this study was to assess the in vitro activity of some antibiotics against Pseudomonas aeruginosa strains to determine the susceptibility patterns of isolates to different antibiotics. Materials and Methods: A total of 233 Pseudomonas aeruginosa isolates obtained from various clinical specimens of hospitalized children in Ali-Asghar hospital of Tehran (Iran) were considered for susceptibility test. These strains were tested against 12 different antibiotics by a disk diffusion method. Of these isolates, 33.9% were from trachea, 31.8% from urine, 6.9% from eye, 5.2% from blood, 5.1% from ear, 1.3% from cerebrospinal fluid, 1.2% from stool, and 14.6% from other sites. In addition, 48.5% of P. aeruginosa strains were isolated from patients in ICUs. Results: The most active antimicrobials were amikacin and other active compounds were gentamicin, ceftazidime, and ciprofloxacin respectively. Isolates from ICUs were more resistant to amikacin and gentamicin as compared to those from non-ICU wards (p<0.05). Isolates from trachea were more resistant to amikacin, gentamicin, ciprofloxacin and ceftazidime than those from other sites (p<0.05).Conclusion: Our study showed that amikacin was the most active agent against P. aeruginosa followed by gentamycin, ceftazidime, and ciprofloxacin. According to our in vitro study results, active antibiotic susceptibility testing and surveillance should be continued in order to curtail the problem of antibiotic resistance.

inflammatory conditions. In this study, the antibacterial effect of methanolic and aqueous extracts of Poulk on bacterial infection of urine, was investigated.Methods: In this experimental study, techniques for determining minimum inhibitory concentration (MIC) of bacterial growth, minimum bactericidal concentration (MBC), and disk diffusion were used to investigate the antibacterial effects of Poulk on the mentioned bacteria. Data were analyzed using analysis of variance and Duncan’s tests. Significance level was considered p<0.05.Results: In this study, Staphylococcus aureus, Klebsiella pneumoniae, and Enterobacter aerogenes bacteria showed sensitivity to aqueous and methanolic extracts of Poulk in different concentrations. Proteus mirabilis bacteria with an inhibition zone diameter of (2.00±0.2 mm) was the most resistant and Staphylococcus aureus bacteria with an inhibition zone diameter of (20.50±0.2mm) was the most sensitive bacteria to the extract effect. The effect of methanolic and aqueous extracts on staphylococcus aureus was the same. Hydro-methanolic extracts showed MIC and MBC, but aqueous extracts had no bactericidal effect on the bacteria.Conclusion: The findings of this research indicate that aqueous and methanolic extracts of poulk have strong antibacterial effects on Enterobacter aerogenes and Klebsiella pneumoniae, and Staphylococcus aureus (bacteria causing urinary infections), but no effect on Proteus mirabilis.