No abstract

The high prevalence of SE genes detected indicates a potential risk for causing animal-originated food poisoning. The increasing prevalence of community-acquired MRSA and its emerging antibiotic resistance in foods is a serious problem for public health.

Background Brucellosis is a zoonotic disease caused by Brucella species. It has been estimated that more than 500,000 new cases of Brucellosis occur annually all around the world. Relapse of the disease is one of the most important challenges. The most important reason for the relapse of brucellosis is the survival of the bacteria inside the macrophages, which makes them safe from the immune system and disrupts drug delivery mechanism. Objectives The present study was performed to assess the effects of Doxycycline-loaded Solid Lipid Nanoparticles (DOX-SLN) on the Brucella melitensis inside macrophages. Methods DOX-SLN was prepared using double emulsion method. The technological characterization of DOX-SLN, including particle size, zeta potential, polydispersity index (PDI), drug loading and encapsulation efficiency were used. Fourier-transform infrared spectroscopy (FTIR) and Differential scanning calorimetry (DSC) were used to assess the interactions between Nanoparticles (NPs) components and crystalline form of doxycycline. Moreover, the effect of DOX-SLN on the bacteria were compared with that of the doxycycline using various methods, including well diffusion, Minimum Inhibitory Concentration (MIC), and investigation of their effects on murine macrophage-like cells cell line J774A.1. Results The means of particle size, zeta potential, PDI, drug loading and encapsulation efficiency were 299 ± 34 nm, − 28.7 ± 3.2 mV, 0.29 ± 0.027, 11.2 ± 1.3%, and 94.9 ± 3.2%, respectively. The morphology of NPs were spherical with a smooth surface. No chemical reaction was occurred between the components. Doxycycline was located within NP matrix in its molecular form. The DOX-SLN significantly decreased the microbial loading within macrophages (3.5 Log) in comparison with the free doxycycline. Conclusions Since the DOX-SLN showed better effects on B. melitensis enclosed in macrophages than the free doxycycline, it is recommended to use it for treating brucellosis and preventing relapse.

The rapid increase of drug resistance and failure of available antibiotics to treat biofilm-associated infections is of great health concern. Accordingly, our study aimed to evaluate the synergistic antibacterial, biofilm inhibitory, and biofilm removal activities of melittin in combination with colistin, imipenem, and ciprofloxacin against multidrug-resistant (MDR) strong biofilm producer Acinetobacter baumannii isolates. The kinetics of biofilm formation were evaluated for the isolates for 144 h. Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum biofilm inhibitory concentrations (MBICs), and biofilm removal activities for melittin and combinations with antibiotics were determined. Inhibition of biofilm-associated protein (bap) expression by melittin was evaluated with real-time polymerase chain reaction (PCR). Field emission scanning electron microscopy (FE-SEM) was used to visualize the effect of synergism on the inhibition of biofilm production. The geometric means of the fractional inhibitory concentration index (FICi) for melittin-colistin, melittin-imipenem, and melittin-ciprofloxacin combinations were calculated as 0.31, 0.24, and 0.94, respectively. Comparing the geometric means of the removal activity for melittin, colistin, imipenem, and combinations of them in both 6 and 24 h showed a significant difference between the groups (p-value < 0.05). Exposure to melittin induced a statistically significant downregulation of bap mRNA levels in all isolates at sub-MIC doses. Analysis of the FE-SEM results demonstrated that the synergism of melittin-colistin at 0.125-0.25 μg inhibited biofilm formation completely. In conclusion, our findings indicate that melittin possesses considerable potential for use in combination with colistin and imipenem to treat infections caused by MDR strong biofilm producer A. baumannii isolates.

A total of 200 cell lines including different human, monkey, mice, hamster and rat cell types were examined for mycoplasma infection status. PCR assay using generic-specific universal primers showed that 40 (20%) of the cell lines are contaminated with mycoplasma. Employment of species-specific primers within these infected cell lines revealed infection with M. hyorhinis (42.5%), M. fermentas (37.5%), M. arginini (37.5%), M. orale (12.5%) and A. laidlawii (7.5%). A number of the cultures were coinfected with 2 or 3 different species. Contaminated samples were treated with BM-Cyclin, Ciprofloxacin and mycoplasma removal agent (MRA). Mycoplasma eradication was subsequently checked by PCR following 2 weeks continuous culture of treated cells in antibiotic free culture medium. Mycoplasmal infections were eradicated in 100, 70 and 42% of infected cell lines when the samples were treated with BM-Cyclin, MRA and Ciprofloxacin, respectively. However, 12% (BM-Cyclin), 62.5% (MRA) and 82.5% (Ciprofloxacin) of mycoplasma regrowth was observed 4 months after the treatment. Notably, the risk of spontaneous culture death was 17.5, 12.5 and 0% for BM-Cyclin, MRA and Ciprofloxacin, respectively.