Background and objectives: Antibiotic resistance is a major public health challenge. The pervasive antibiotic misuse can lead to increased antibiotic resistance. Thus, there is a need for discovery of new compounds against drug-resistant microorganisms. We synthesized new series of 1, 3, 4-oxadiazole derivatives (4a-4d) and evaluated the antibacterial and antifungal activity of the derivatives against Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii, Klebsiella pneumoniae, Aspergillus fumigatus and Aspergillus flavus. Methods: The new derivatives of 1, 3, 4-oxadiazole were synthesized using a single-stage, high-yield method. The structure of the new compounds was confirmed by infrared spectroscopy, carbon-nuclear magnetic resonance and hydrogen-nuclear magnetic resonance. Then, antibacterial and antifungal activities of the prepared derivatives (1 mg/ml) were evaluated by determining minimum inhibitory concentration and minimum bactericidal/fungicidal concentration using the agar well diffusion method. Results: All synthesized compounds, especially (4d) with methoxyphenyl group, exhibited powerful antibacterial activity against the tested bacteria. However, the compounds had no antifungal effect. Conclusion: Our findings indicate the antibacterial potential of the novel synthetic 1, 3, 4-oxadiazole compounds.

Background & Objectives: Nanotechnology is one of great important part of technology. Nanoparticles can be used in different applications for industrial, medical, military and personal use. The objectives of this study were preparation of Polystyrene/ZnO nanocomposite films via a simple method and investigation of antibacterial activity of them.Materials and Methods: Polystyrene/ZnO nanoparticle (PS/nano-ZnO) composite films were prepared via simple method with 0, 0.1, 1 and 2.5% wt concentration of ZnO and characterized by scanning electron microscopy (SEM). The antibacterial properties of the product were investigated against Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Bacillus cereus.Results: The survival ratio of L. monocytogenes, E. coli, S. aureus and B. cereus decreased with increase of ZnO content on PS/nano-ZnO composite films and the best antibacterial activity was obtained with 2.5% wt ZnO-PS composite films for all bacteria. Results show the larger sensitivity of the S. aureus compared to other bacteria.Conclusion: The treated fabric with ZnO NP indicates significant improve for antibacterial properties for polystyrene fabric.

Background: Antibiotics called macrolide, lincosamide and streptogramin B (MLSB) are being used to treat staphylococci infections. Multiple pathways that impart resistance to MLSB antibiotics have been confirmed to cause clinical failure. The present work aimed to determine the frequency of constitutive and inducible clindamycin resistant among coagulase-negative staphylococci (CoNS) isolates of different clinical samples in Al-Basrah governorate, Iraq. Methods: The 28 CoNS, traditional techniques and the Vitek®, 2 system were used to identify the isolates. The disk diffusion technique was used to detect methicillin resistance and antibiotic sensitivity patterns via cefoxitin, gentamicin, ciprofloxacin, amikacin, teicoplanin, linezolid, doxycycline and vancomycin disks. Erythromycin and clindamycin antibiotic disks was used to detect the inducible and constitutive clindamycin resistance as well as a D-test according to CLSI guidelines. Results: Among 28 CoNS isolated, the Staphylococcus aureus 11(39. 29%), Staphylococcus epidermidis 7(25 %), Staphylococcus haemolyticus 4(14. 29%) and Staphylococcus saprophyticus 3 (10. 71%) were predominant isolated species. Out of 28 CoNS isolates, 15(53. 57%) were methicillin resistant coagulasenegative staphylococci (MRCoNS) isolates and 13(46. 43%) were methicillin sensitive coagulase-negative staphylococci (MSCoNS) isolates. The 15(53. 57%) isolates out of 28 CoNS, showed erythromycin resistance while 6(40%) isolates out of 15 CoNS, showed inducible macrolide-lincosamide-streptogramin B (iMLSB) and 2(13. 3%) of CONS isolated showed constitutive macrolide-lincosamide-streptogramin B (cMLSB). Conclusions: In order to achive the best result in choosing the suitable treatment and avoiding the loses the money and time, it is better to use the D-test for inducible clindamycin resistance in the daily routine work of antibiotic susceptibility testing in hospital and private clinical laboratories.

Objectives: The purpose was to determine the antibacterial properties of propolis and to evaluate its use as an antibacterial mouthwash with minimal complications. Materials and Methods: In this experimental laboratory study, an alcoholic propolis extract was prepared. The minimum inhibitory concentration (MIC) was calculated for four bacterial species including Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Lactobacillus acidophilus (L. acidophilus), and Enterococcus faecalis (E. faecalis) using agar dilution. According to the MIC, a propolis antibacterial mouthwash was produced and compared to water, chlorhexidine (CHX), and Listerine using laboratory rats for clinical examination. Salivary specimens of rats were collected at 12 hours, 1 week, and 2 weeks after using the mouthwash and examined by the real-time polymerase chain reaction (RT-PCR). Data were analyzed using one-way analysis of variance (ANOVA) and repeated measures ANOVA (α =0. 05). Results: The results of agar dilution by the number of colony-forming units (CFU) showed the lowest MIC for S. aureus and the highest for L. acidophilus. The results of the RT-PCR indicated that water alone had no effect on the level of oral bacteria. Propolis mouthwash showed a significant difference with CHX and Listerine (P<0. 05) in terms of the number of S. mutans, E. faecalis, and L. acidophilus colonies, while CHX and Listerine were less efficient. There was no significant difference between CHX and propolis (P=0. 110) regarding S. aureus colonies, but Listerine had a lower efficacy than either (P<0. 05). Conclusions: According to the results, propolis mouthwash was more efficient against the studied oral bacteria compared to CHX and Listerine.