Peracetic acid activity on biofilm formed by Escherichia coli isolated from an industrial water system.

One of the major problems in industrial water systems is the generation of biofilm, which is resistant to antimicrobial agents and causes failure of sanitization policy. This work aimed to study the anti-biofilm activity of peracetic acid (PAA) at contact times and temperatures combinations. To this end, a 96-well microtiter-based calorimetric method was applied in in vitro biofilm production using Escherichia coli, isolated from the water supply system of a pharmaceutical plant. The phenotypic and phylogenetic tests confirmed that the isolated bacteria belong to strains of Escherichia coli. The anti-biofilm activity of peracetic acid on formed biofilm was investigated at concentrations of 0·15-0·5% for a contact time of 5-15 min at 20-60°C. The maximum biofilm formation by MTP method using an Escherichia coli isolate was achieved in 96-h incubation in TSB containing wells at 37°C. Biofilm formation rate shown to be high by the environmental isolate compared with that of standard strain. PAA at concentrations above 0·25%, the temperature of 40°C and a minimum of 10 min of contact time was effective in the eradication of biofilm in an MTP-based system.

Study of Antimicrobial Effects of Clarithromycin Loaded PLGA Nanoparticles against Clinical Strains of Helicobacter pylori.

Clarithromycin (CLR) formulation was prepared as PLGA nanoparticles in order to enhance the therapeutic effects using the distinctive features of a nanoparticulate delivery system. CLR loaded PLGA nanoparticles were prepared by Quasi Emulsion Solvent Diffusion (QESD) method using Poly lactic-co-Glycolic Acid (PLGA) as a biodegradable polymer. Antibacterial activity of the prepared formulations was evaluated against clinical strains of Helicobacter pylori, isolated from gastric biopsies of patients with gastritis, duodenal ulcer, peptic ulcer, and gastroesophageal reflux disease undergoing endoscopy, by using agar dilution method.Spherical nanoparticles with relatively narrow size distribution (between 200 and 800 nm) in the size range of 305 ± 138, 344 ± 148 and 362 ± 110 nm were achieved for F22, F23 and F23 respectively. CLR encapsulation percentages were measured to be 57.4 ± 4.3 to 80.2 ± 4.0%. CLR loaded PLGA nanoparticles showed equal or enhanced eradication effect against H. pylori strains according to the declined MIC values in comparison with the untreated CLR.In conclusion, the prepared CLR nanoformulation showed appropriate physicochemical properties and improved activity against H. pylori that could be a suitable candidate for oral preparations.

Study of antimicrobial effects of vancomycin loaded PLGA nanoparticles against enterococcus clinical isolates.

Researchers have demonstrated that antimicrobial agents in nanoparticle (NP) forms have better activities. Vancomycin (VCM), as a glycopeptide antibiotic with antimicrobial activity against gram positive bacteria, is poorly absorbed from the intestinal tract. Enterococcus is a genus of bacteria that became resistant to a wide range of antibiotics in last decades, and cause severe infections in hospitalized patients. This paper describes preparation of VCM--loaded poly (lactic-co-glycolic acid) (PLGA) NPs and compares the antimicrobial effects with drug solution against clinical Enterococcus isolates. VCM-loaded PLGA NPs were fabricated by W1/O/W2 solvent evaporation method. The comparison of obtained Minimum Inhibitory Concentration (MIC) values showed a significant decrease in the antimicrobial effect of VCM -loaded NPs. Results also indicated that the potency of the NPs against VCM resistant isolates of Enterococcus was less than VCM susceptible isolates. The reduced antimicrobial effect of formulated NPs in invitro condition is perhaps related to the strong electrostatic linkage between hydrophilic drug (VCM) and hydrophobic polymer (PLGA) that lead to the slow release of the antibiotic from polymeric NPs.

Preparation and characterization of chitosan/ß-cyclodextrin nanoparticles containing plasmid DNA encoding interleukin-12.

Interleukin-12 (IL-12) as a cytokine has been proved to possess antitumor effects via stimulating the immune system. Non-viral gene delivery systems offer several advantages, including easiness in production, low cost, safety; low immunogenicity and can carry higher amounts of genetic material without limitation on their sizes.pUMVC3-hIL12 loaded Low Molecular Weight chitosan/ß-cyclodextrin (LMW CS/CD) nanoparticles were prepared using ionotropic gelation method and characterized in terms of size, zeta potential, polydispersity index, morphology, loading efficiency and cytotoxicity against the CT-26 colon carcinoma cell line.All prepared particles were spherical in shape and nano-sized (171.3±2.165 nm, PdI: 0.231±0.014) and exhibited a positive zeta potential (34.3±1.55). The nanoparticles demonstrated good DNA encapsulation efficiencies (83.315%±2.067). Prepared pUMVC3-hIL12 loaded LMW CS/CD nanoparticles showed no cell toxicity in murine CT-26 colon carcinoma cells. At the concentration of 0.1 µg/ml of nanoparticles, the transfection ability was obviously higher than that of the naked DNA.LMW CS/CD-plasmid DNA nanoparticles encoding IL-12 prepared using ionotropic gelation method with no toxic effect on the tested cells can be considered as a basis for further gene delivery studies both in vitro and in vivo to enhance the expression of IL-12.

Magnetic nanoparticles for antimicrobial drug delivery.

Magnetic nanoparticles (MNP), fabricated by loading a therapeutic agent into a magnetic nanoparticle through encapsulation or adsorption, have gained particular interest during the last decade because of their intrinsic magnetic nature as well as enhanced physicochemical properties. Using their superior specifications MNPs can address the shortcomings of traditional therapeutic agents especially antimicrobials. The aim of this review, therefore, is to focus on the properties, fabrication and most recent finding in the application of MNPs for antimicrobial delivery.

Natural antimicrobial peptides from bacteria: characteristics and potential applications to fight against antibiotic resistance.

Because of the emergence of antibiotic-resistant pathogens worldwide, a number of infectious diseases have become difficult to treat. This threatening situation is worsened by the fact that very limited progress has been made in developing new and potent antibiotics in recent years. However, a group of antimicrobials, the so-called bacteriocins, have been much studied lately because they hold a great potential in controlling antibiotic-resistant pathogens. Bacteriocins are small antimicrobial peptides (AMPs) produced by numerous bacteria. They often act toward species related to the producer with a very high potency (at pico- to nanomolar concentration) and specificity. The common mechanisms of killing by bacteriocins are destruction of target cells by pore formation and/or inhibition of cell wall synthesis. Several studies have revealed that bacteriocins display great potential in the medical sector as bacteriocinogenic probiotics and in the clinic as therapeutic agents. In this review, we discuss the emerging antibiotic resistance and strategies to control its dissemination, before we highlight the potential of AMPs from bacteria as a new genre of antimicrobial agents.

Antibacterial activity of clarithromycin loaded PLGA nanoparticles.

Novel drug delivery systems such as nanoparticles (NPs) have been proved to enhance the effectiveness of many drugs. Clarithromycin is a broad spectrum macrolide antibiotic, used in many infectious conditions like upper and lower respiratory tract infections, and skin and other soft tissue infections. This paper describes the preparation and enhanced in vitro antibacterial activities of clarithromycin loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles. A modified quasi-emulsion solvent diffusion (MQESD) method was used to prepare clarithromycin (CLR) NPs. The antibacterial activity of the NPs was evaluated using the agar well diffusion method against Escherichia coli (PTCC 1330), Haemophilus influenzae (PTCC 1623), Salmonella typhi (PTCC 1609), Staphylococcus aureus (PTCC 1112) and Streptococcus pneumoniae (PTCC 1240). The inhibition zone diameters related to each nano formulation were compared with those for untreated CLR at the same concentrations. The results indicated that the mean inhibition zone diameters of NPs against all the bacteria tested were significantly higher than those of untreated CLR, particularly in the case of S. aureus. The increased potency of CLR NPs may be related to some physicochemical properties of NPs like modified surface characteristics, lower drug degradation, and increased drug adsorption and uptake.

Delivery of nanoparticulate drug delivery systems via the intravenous route for cancer gene therapy.

While the systemic route of administration enables therapeutic genes to spread through the bloodstream and access target cells, it is a challenge to achieve this. Several studies demonstrate that systemic administration of therapeutic genes or other nucleic acid-based constructs such as siRNA to solid tumors as well as cancer metastases are better with nanoparticulate systems compared to administration of free (uncomplexed) nucleic acids. Nanoparticle-based nucleic acid delivery systems might be more pertinent, due to the several privileges in terms of enhanced tissue penetrability, improved cellular uptake and to a lesser extent, targeted gene delivery to the cells of interest provided targeting ligands are used. Systemic delivery of nanoplexes has already been reported with different nanoparticles containing DNA via various routes of administration. The goal of the present article is to review the current state of intravenous delivery of nanoparticles for gene therapy of cancer.

The effect of hydrophilic and lipophilic polymers and fillers on the release rate of atenolol from HPMC matrices.

The objective of this study is to investigate the effect of various polymers, and fillers, and their concentrations on the release rate of atenolol from polymeric matrices. Four polymers namely hydroxypropylmethylcellulose (HPMC), Eudragit RSPO, ethylcellulose (EC) and sodium carboxymethylcellulose (NaCMC) were used. The dissolution profiles showed that an increase in the concentration of HPMC and EC resulted in a reduction in the release rate of atenolol. The results indicate that it is difficult to obtain a zero-order release from the matrices containing either HPMC or EC. It is also observed that the amount of HPMC played a dominant role, affecting the drug release in binary mixtures of Eudragit-HPMC. Generally, the presence of NaCMC caused an increase in the release rate of atenolol from HPMC matrices. To determine the effect of fillers on the release rate of atenolol from HPMC matrices, lactose (a soluble filler) and dicalcium phosphate (an insoluble filler) were used. The results showed that an increase in the concentration of fillers resulted in an increase in the release rate of the drug from matrices and hydrophilicity or hydrophobicity of fillers had no significant effect on the release profile. In order to determine the mode of release, the data were analysed based on the equation Q = K (t - l)(m). Values of m were in the range of 0.32-0.99 indicating that release was controlled by both diffusion and erosion, depending on the type of polymer and concentration.