Biofilm formation, antibiotic-resistance and clonal relatedness among clinical isolates of Acinetobacterbaumannii.

In this work, the antibiotic resistance, biofilm formation capability, and clonal relatedness of 50 A. baumannii isolates collected from three hospitals in Ardabil city, Iran, were evaluated. Antibiotic sensitivity and biofilm formation of isolates were determined by disk diffusion and microtiter-plate methods, respectively. Molecular typing of isolates was also performed using repetitive sequence-based PCR (REP-PCR). The majority of isolates were resistant to cephems, aminoglycosides, and carbapenems, with 80 % classified as multi-drug resistant (MDR). While, only isolates collected from blood and tracheal were resistant to colistin. Additionally, 42 isolates (84 %) had biofilm formation capability. According to rep-PCR results, 34 isolates showed similar banding patterns, while 16 isolates had unique banding patterns. Finally, based on the molecular analysis, there was a direct relationship between biofilm formation and the antibiotic resistance of isolates. In other words, MDR isolates had a higher ability to form biofilm.

Toxicity effects of AgZnO nanoparticles and rifampicin on Mycobacterium tuberculosis into the macrophage.

The World Health Organization acknowledges tuberculosis as a global threat. Tuberculosis infection is one of the top 10 causes of death worldwide. Nanotechnology and microbiology researchers are looking for new and safe nano drugs for eliminating Mycobacterium tuberculosis, the causative agent of tuberculosis. In this study, AgZnO nano-crystals (AgZnONCs) is synthesized via the decomposition of the precursor of oxalate method. Characterization of AgZnONCs were evaluated. Next, various concentrations of AgZnONCs, as well AgZnONCs+Rifampicin, were prepared. The MTT assay was employed to study the viability of human macrophage cell lines (THP-1) exposed to AgZnONCs. The bactericidal effects of AgZnONCs and AgZnONCs+Rifampicin were studied by Minimum Bactericidal Concentration (MBC) test. Subsequently, THP-1 were infected by H37 Rv strain of M. tuberculosis (H37 RvMtb). Also, bactericidal effects of AgZnONCs and AgZnONCs+Rifampicin were compared with ex-vivo conditions. The MBC of AgZnONCs and AgZnONCs+Rifampicin were ratios of 1:4 and 1:32 respectively (p-value <0.05). Also, more than 50% and 80% of THP-1 were alive in ratios of 1:4 and 1:32 in the presence of AgZnONCs, respectively. All phagocytic H37 RvMtb were killed in the presence of AgZnONCs+Rifampicin (p-value <0.05), while AgZnONCs were not able to kill all the H37 RvMtb (p-value >0.05). This study showed that, AgZnONCs+Rifampicin has the most anti-tubercular behavior with respect to the macrophages.

Bactericidal impact of Ag, ZnO and mixed AgZnO colloidal nanoparticles on H37Rv Mycobacterium tuberculosis phagocytized by THP-1 cell lines.

The purpose of this research project was to infection of human macrophages (THP-1) cell lines by H37Rv strain of Mycobacterium tuberculosis (H37RvMTB) and find out the ratio/dilution of mixture silver (Ag NPs) and zinc oxide nanoparticles (ZnO NPs) whose ability to eliminate phagocytized bacteria compared to rifampicin. The colloidal Ag NPs and ZnO NPs were synthesized and their characteristics were evaluated. The THP-1 cell lines were infected with different concentration of H37RvMTB. Next, the infected cells were treated with different ratios/dilutions of Ag NPs, ZnO NPs and rifampicin. The THP-1 were lysed and were cultured in Lowenstein-Jensen agar medium, for eight weeks. The TEM and AFM images of NPs and H37RvMTB were supplied. It is observed that Ag NPs, 2Ag:8ZnO and 8Ag:2ZnO did not have any anti-tubercular effects on phagocytized H37RvMTB. Conversely, ZnO NPs somehow eliminated 18.7 × 104 CFU ml-1 of H37RvMTB in concentration of ∼ 0.468 ppm. To compare with 40 ppm of rifampicin, ∼ 0.663 ppm of 5Ag:5ZnO had the ability to kill of H37RvMTB, too. Based on previous research, ZnO NPs had strong anti-tubercular impact against H37RvMTB to in-vitro condition, but it was toxic in concentration of ∼ 0.468 ppm to both of THP-1 and normal lung (MRC-5) cell lines. It also seems that 5Ag:5ZnO is justified because in concentration of ∼ 0.663 ppm of 5Ag:5ZnO, phagocytized H37RvMTB into the THP-1 had died without any toxicity effects against THP-1 and also MRC-5 cell lines. It is obvious that the mixture of colloidal silver and zinc oxide NPs with ratio of 5Ag:5ZnO would be trustworthy options as anti-tubercular nano-drugs in future researches.

Development a rapid and accurate multiplex real time PCR method for the detection Chlamydia trachomatis and Mycoplasma hominis.

BACKGROUND: Sexually transmitted diseases easily spread among sexually active people and often have no symptoms. Rapid and accurate method for detecting these infections are necessary in early stages. The traditional detection methods of them are difficult and time-consuming. METHODS: In this study, multiplex real time PCR was optimized for rapid identification of Chlamydia trachomatis and Mycoplasma hominis in a single tube and was performed with our designed primers. The sensitivity test was carried out to designed primers with diluted genomic DNA. To defined the specificity, non STD bacteria were used as DNA template. RESULTS: This study indicated that the developed multiplex real time PCR can be an effective alternative procedure to the conventional methods for rapid and accurate identification of C Chlamydia trachomatis and Mycoplasma hominis. Multiplex real-time PCR Results of them were checked with melting curves. The sensitivity of our designed primer by multiplex real time PCR for Chlamydia trachomatis and Mycoplasma hominis were 4.78×1010 and 8.35×1010 , respectively, Which the primers did not amplify any product from a non-STD species. CONCLUSIONS: Multiplex real time PCR by our new primers and analysis of melting curves were successfully usable for rapid and accurate detection of Chlamydia trachomatis and Mycoplasma hominis. This assay instead of traditional culture method, has considerable potential to be rapid, accurate and highly sensitive molecular diagnostic tool for simultaneous and direct detection.