c-Jun N-terminal kinase-dependent apoptotic photocytotoxicity of solvent exchange-prepared curcumin nanoparticles.

Indian spice curcumin is known for its anticancer properties, but the anticancer mechanisms of nanoparticulate curcumin have not been completely elucidated. We here investigated the in vitro anticancer effect of blue light (470 nm, 1 W)-irradiated curcumin nanoparticles prepared by tetrahydrofuran/water solvent exchange, using U251 glioma, B16 melanoma, and H460 lung cancer cells as targets. The size of curcumin nanocrystals was approximately 250 nm, while photoexcitation induced their oxidation and partial agglomeration. Although cell membrane in the absence of light was almost impermeable to curcumin nanoparticles, photoexcitation stimulated their internalization. While irradiation with blue light (1-8 min) or nanocurcumin (1.25-10 µg/ml) alone was only marginally toxic to tumor cells, photoexcited nanocurcumin displayed a significant cytotoxicity depending both on the irradiation time and nanocurcumin concentration. Photoexcited nanocurcumin induced phosphorylation of c-Jun N-terminal kinase (JNK), mitochondrial depolarization, caspase-3 activation, and cleavage of poly (ADP-ribose) polymerase, indicating apoptotic cell death. Accordingly, pharmacologial inhibition of JNK and caspase activity rescued cancer cells from photoexcited nanocurcumin. On the other hand, antioxidant treatment did not reduce photocytotoxicity of nanocurcumin, arguing against the involvement of oxidative stress. By demonstrating the ability of photoexcited nanocurcumin to induce oxidative-stress independent, JNK- and caspase-dependent apoptosis, our results support its further investigation in cancer therapy.

Phloroglucinol-Based Carbon Quantum Dots/Polyurethane Composite Films: How Structure of Carbon Quantum Dots Affects Antibacterial and Antibiofouling Efficiency of Composite Films.

Nowadays, bacteria resistance to many antibiotics is a huge problem, especially in clinics and other parts of the healthcare system. This critical health issue requires a dynamic approach to produce new types of antibacterial coatings to combat various pathogen microbes. In this research, we prepared a new type of carbon quantum dots based on phloroglucinol using the bottom-up method. Polyurethane composite films were produced using the swell-encapsulation-shrink method. Detailed electrostatic force and viscoelastic microscopy of carbon quantum dots revealed inhomogeneous structure characterized by electron-rich/soft and electron-poor/hard regions. The uncommon photoluminescence spectrum of carbon quantum dots core had a multipeak structure. Several tests confirmed that carbon quantum dots and composite films produced singlet oxygen. Antibacterial and antibiofouling efficiency of composite films was tested on eight bacteria strains and three bacteria biofilms.

Antibacterial and Antibiofouling Activities of Carbon Polymerized Dots/Polyurethane and C60/Polyurethane Composite Films.

The cost of treatment of antibiotic-resistant pathogens is on the level of tens of billions of dollars at the moment. It is of special interest to reduce or solve this problem using antimicrobial coatings, especially in hospitals or other healthcare facilities. The bacteria can transfer from medical staff or contaminated surfaces to patients. In this paper, we focused our attention on the antibacterial and antibiofouling activities of two types of photodynamic polyurethane composite films doped with carbon polymerized dots (CPDs) and fullerene C60. Detailed atomic force, electrostatic force and viscoelastic microscopy revealed topology, nanoelectrical and nanomechanical properties of used fillers and composites. A relationship between the electronic structure of the nanocarbon fillers and the antibacterial and antibiofouling activities of the composites was established. Thorough spectroscopic analysis of reactive oxygen species (ROS) generation was conducted for both composite films, and it was found that both of them were potent antibacterial agents against nosocomial bacteria (Klebsiela pneumoniae, Proteus mirabilis, Salmonela enterica, Enterococcus faecalis, Enterococcus epidermis and Pseudomonas aeruginosa). Antibiofouling testing of composite films indicated that the CPDs/PU composite films eradicated almost completely the biofilms of Pseudomonas aeruginosa and Staphylococcus aureus and about 50% of Escherichia coli biofilms.

Determination of Photothermal and EMI Shielding Efficiency of Graphene-Silver Nanoparticle Composites Prepared under Low-Dose Gamma Irradiation.

Silver nanoparticles (Ag NPs) have been produced by low-dose (1-20 kGy) gamma irradiation of silver nitrate in the presence of graphene-based material (graphene oxide or electrochemically exfoliated graphene). The large surface area of those graphene-based materials combined with the presence of oxygen-containing functional groups on the surface provided successful nucleation and growth of Ag nanoparticles, which resulted in a uniformly covered graphene surface. The obtained Ag nanoparticles were spherical with a predominant size distribution of 10-50 nm for graphene oxide and 10-100 nm for electrochemically exfoliated graphene. The photothermal efficiency measurement showed a temperature increase upon exposure to a 532 nm laser for all samples and the highest photothermal efficiency was measured for the graphene oxide/Ag NP sample prepared at 5 kGy. Electromagnetic interference (EMI) shielding efficiency measurements showed poor shielding for the composites prepared with graphene oxide. On the other hand, all composites prepared with electrochemically exfoliated graphene showed EMI shielding to some extent, and the best performance was measured for the samples prepared at 5 and 20 kGy doses.

Reduction in Pathogenic Biofilms by the Photoactive Composite of Bacterial Cellulose and Nanochitosan Dots under Blue and Green Light.

In this study, nanochitosan dots (ChiDs) were synthesized using gamma rays and encapsulated in bacterial cellulose (BC) polymer matrix for antibiofilm potential in photodynamic therapy. The composites were analyzed for structural changes using SEM, AFM, FTIR, XRD, EPR, and porosity measurements. Additionally, ChiD release was assessed. The results showed that the chemical composition remained unaltered, but ChiD agglomerates embedded in BC changed shape (1.5-2.5 µm). Bacterial cellulose fibers became deformed and interconnected, with increased surface roughness and porosity and decreased crystallinity. No singlet oxygen formation was observed, and the total amount of released ChiD was up to 16.10%. Antibiofilm activity was higher under green light, with reductions ranging from 48 to 57% under blue light and 78 to 85% under green light. Methicillin-resistant Staphylococcus aureus was the most sensitive strain. The new photoactive composite hydrogels show promising potential for combating biofilm-related infections.

Structural, optical, and bioimaging characterization of carbon quantum dots solvothermally synthesized from o-phenylenediamine.

Carbon quantum dots as a novel type of carbon nanomaterials have attracted the attention of many researchers because of their unique optical, antibacterial, and anticancer properties as well as their biocompatibility. In this study, for the first time, carbon quantum dots were prepared from o-phenylenediamine dissolved in toluene by a solvothermal route. Subsequently, the prepared carbon quantum dots were encapsulated into polyurethane films by a swelling-encapsulation-shrink method. Analyses of the results obtained by different characterization methods (AFM, TEM, EDS, FTIR, photoluminescence, and EPR) indicate the significant influence of the precursor on structural, chemical, and optical properties. Antibacterial and cytotoxicity tests showed that these dots did not have any antibacterial potential, because of the low extent of reactive oxygen species production, and showed low dark cytotoxicity. By investigating the cellular uptake, it was established that these dots penetrated the HeLa cells and could be used as probes for bioimaging.

Toxicity of pristine versus functionalized fullerenes: mechanisms of cell damage and the role of oxidative stress.

The fullerene C(60), due to the physicochemical properties of its spherical cage-like molecule build exclusively from carbon atoms, is able to both scavenge and generate reactive oxygen species. While this unique dual property could be exploited in biomedicine, the low water solubility of C(60) hampers the investigation of its behavior in biological systems. The C(60) can be brought into water by solvent extraction, by complexation with surfactants/polymers, or by long-term stirring, yielding pristine (unmodified) fullerene suspensions. On the other hand, a modification of the C(60) core by the attachment of various functional groups results in the formation of water-soluble fullerene derivatives. Assessment of toxicity associated with C(60) preparations is of pivotal importance for their biomedical application as cytoprotective (antioxidant), cytotoxic (anticancer), or drug delivery agents. Moreover, the widespread industrial utilization of fullerenes may also have implications for human health. However, the alterations in physicochemical properties imposed by the utilization of different methods for C(60) solubilization profoundly influence toxicological effects of fullerene preparations, thus making the analysis of their potential therapeutic and environmental toxicity difficult. This review provides a comprehensive evaluation of the in vitro and in vivo toxicity of fullerenes, focusing on the comparison between pristine and derivatized C(60) preparations and the mechanisms of their toxicity to mammalian cells and tissues.

Antioxidative and Photo-Induced Effects of Different Types of N-Doped Graphene Quantum Dots.

Due to the increasing number of bacterial infections and the development of resistivity toward antibiotics, new materials and approaches for treatments must be urgently developed. The production of new materials should be ecologically friendly considering overall pollution with chemicals and economically acceptable and accessible to the wide population. Thus, the possibility of using biocompatible graphene quantum dots (GQDs) as an agent in photodynamic therapy was studied. First, dots were obtained using electrochemical cutting of graphite. In only one synthetic step using gamma irradiation, GQDs were doped with N atoms without any reagent. Obtained dots showed blue photoluminescence, with a diameter of 19-89 nm and optical band gap of 3.23-4.73 eV, featuring oxygen-containing, amino, and amide functional groups. Dots showed antioxidative activity; they quenched •OH at a concentration of 10 µg·mL-1, scavenged DPPH• radicals even at 5 µg·mL-1, and caused discoloration of KMnO4 at 30 µg·mL-1. Under light irradiation, dots were able to produce singlet oxygen, which remained stable for 10 min. Photoinduced effects by GQDs were studied on several bacterial strains (Listeria monocytogenes, Bacillus cereus, clinical strains of Streptococcus mutans, S. pyogenes, and S. sangunis, Pseudomonas aeruginosa, and one yeast strain Candida albicans) but antibacterial effects were not noticed.

Antibacterial composite hydrogels of graphene quantum dots and bacterial cellulose accelerate wound healing.

The increased antibiotic resistance of pathogenic bacteria requires intense research of new wound healing agents. Novel wound dressings should be designed to provide wound disinfection, good moisture, and fast epithelization. In this study, bacterial cellulose (BC) was impregnated with graphene quantum dots (GQDs) for potential use in wound healing treatment. The BC was successfully loaded with approximately 11.7 wt% of GQDs. The actual release of GQDs from new designed composite hydrogels were 13%. Novel GQDs-BC hydrogel composites are biocompatible and showed significant inhibition towards Staphylococcus aureus and Streptococcus agalactiae and bactericidal effect towards Methicillin-resistant Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The in vitro healing analysis showed significant migration of human fibroblasts after the GQDs-BC hydrogels application. Furthermore, after 72 h exposure to GQDs-BC, endothelial nitric oxide synthase, vascular endothelial growth factor A, matrix metallopeptidase 9, and Vimentin gene expression in fibroblast were significantly upregulated promoting angiogenesis. GQDs-BC hydrogel composites showed very good wound fluid absorption and water retention, which satisfies good dressing properties. All obtained results propose new designed GQDs-BC hydrogels as potential wound dressings.

Highly Efficient Antibacterial Polymer Composites Based on Hydrophobic Riboflavin Carbon Polymerized Dots.

Development of new types of antimicrobial coatings is of utmost importance due to increasing problems with pathogen transmission from various infectious surfaces to human beings. In this study, new types of highly potent antimicrobial polyurethane composite films encapsulated by hydrophobic riboflavin-based carbon polymer dots are presented. Detailed structural, optical, antimicrobial, and cytotoxic investigations of these composites were conducted. Low-power blue light triggered the composites to eradicate Escherichia coli in 30 min, whereas the same effect toward Staphylococcus aureus was reached after 60 min. These composites also show low toxicity against MRC-5 cells. In this way, RF-CPD composites can be used for sterilization of highly touched objects in the healthcare industry.

Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death.

We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuroblastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP). GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (•OH), superoxide anion (O2•-), and lipid peroxidation. Nonselective antioxidants, •OH scavenging, and iron chelators, but not superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagy-limiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proautophagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early (wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •OH/NO scavenging and induction of cytoprotective autophagy.

Chronic wound dressings - Pathogenic bacteria anti-biofilm treatment with bacterial cellulose-chitosan polymer or bacterial cellulose-chitosan dots composite hydrogels.

Since the pathogenic bacteria biofilms are involved in 70% of chronic infections and their resistance to antibiotics is increased, the research in this field requires new healing agents. New composite hydrogels were designed as potential chronic wound dressings composed of bacterial cellulose (BC) with chitosan polymer (Chi) - BC-Chi and chitosan nanoparticles (nChiD) - BC-nChiD. nChiD were obtained by gamma irradiation at doses: 20, 40 and 60 kGy. Physical and chemical analyses showed incorporation of Chi and encapsulation of nChiD into BC. The BC-Chi has the highest average surface roughness. BC-nChiD hydrogels show an irradiated dose-dependent increase of average surface roughness. New composite hydrogels are biocompatible with excellent anti-biofilm potential with up to 90% reduction of viable biofilm and up to 65% reduction of biofilm height. The BC-nChiD showed better dressing characteristics: higher porosity, higher wound fluid absorption and faster migration of cells (in vitro healing). All obtained results confirmed both composite hydrogels as promising chronic wound healing agents.

Bactericidal and antioxidant bacterial cellulose hydrogels doped with chitosan as potential urinary tract infection biomedical agent.

Therapy of bacterial urinary tract infections (UTIs) and catheter associated urinary tract infections (CAUTIs) is still a great challenge because of the resistance of bacteria to nowadays used antibiotics and encrustation of catheters. Bacterial cellulose (BC) as a biocompatible material with a high porosity allows incorporation of different materials in its three dimensional network structure. In this work a low molecular weight chitosan (Chi) polymer is incorporated in BC with different concentrations. Different characterization techniques are used to investigate structural and optical properties of these composites. Radical scavenging activity test shows moderate antioxidant activity of these biocompatible composites whereas in vitro release test shows that 13.3% of chitosan is released after 72 h. Antibacterial testing of BC-Chi composites conducted on Gram-positive and Gram-negative bacteria causing UTIs and CAUTIs (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) and encrustation (Proteus mirabilis) show bactericidal effect. The morphology analysis of bacteria after the application of BC-Chi shows that they are flattened with a rough surface, with a tendency to agglomerate and with decreased length and width. All obtained results show that BC-Chi composites might be considered as potential biomedical agents in treatment of UTIs and CAUTIs and as a urinary catheter coating in encrustation prevention.

Photoactive and antioxidant nanochitosan dots/biocellulose hydrogels for wound healing treatment.

Bacterial infection and their resistance to known antibiotics delays wound healing. In this study, nanochitosan dots (nChiD) produced by gamma irradiation have been encapsulated in bacterial cellulose (BC) polymer matrix to study the antibacterial potentials of these nanocomposites and their possible usage in wound healing treatment (scratch assay). Detailed analyses show that nChiDs have disc-like shape and average diameter in the range of 40 to 60 nm depending of the applied dose. All nChiDs as well as BC-nChiD nanocomposites emit green photoluminescence independently on the excitation wavelengths. The new designed nanocomposites do not have a cytotoxic effect; antioxidant analysis shows their moderate radical scavenging activity whereas antibacterial properties show significant growth inhibition of strains mostly found in difficult-to-heal wounds. The obtained results confirm that new designed BC-nChiD nanocomposites might be potential agent in wound healing treatment.

Oxidative stress-mediated hemolytic activity of solvent exchange-prepared fullerene (C60) nanoparticles.

The present study investigated the hemolytic properties of fullerene (C(60)) nanoparticles prepared by solvent exchange using tetrahydrofuran (nC(60)THF), or by mechanochemically assisted complexation with macrocyclic oligosaccharide gamma-cyclodextrin (nC(60)CDX) or the copolymer ethylene vinyl acetate-ethylene vinyl versatate (nC(60)EVA-EVV). The spectrophotometrical analysis of hemoglobin release revealed that only nC(60)THF, but not nC(60)CDX or nC(60)EVA-EVV, was able to cause lysis of human erythrocytes in a dose- and time-dependent manner. Atomic force microscopy revealed that nC(60)THF-mediated hemolysis was preceded by erythrocyte shrinkage and increase in cell surface roughness. A flow cytometric analysis confirmed a decrease in erythrocyte size and demonstrated a significant increase in reactive oxygen species production in red blood cells exposed to nC(60)THF. The nC(60)THF-triggered hemolytic activity was efficiently reduced by the antioxidants N-acetylcysteine and butylated hydroxyanisole, as well as by serum albumin, the most abundant protein in human blood plasma. These data indicate that nC(60)THF can cause serum albumin-preventable hemolysis through oxidative stress-mediated damage of the erythrocyte membrane.

Graphene quantum dots as singlet oxygen producer or radical quencher - The matter of functionalization with urea/thiourea.

Due to their low cost and possible green synthesis, high stability and resistance to photobleaching, graphene quantum dots (GQDs) can be considered as one of the class of carbon nanomaterials which may have great potential as an agent for photosensitized oxygen activation. In such a way, GQDs can be used as a theranostic agent in photodynamic therapy. In this work pristine GQDs, GQDs irradiated with gamma rays and GQDs doped with N and N, S atoms are produced using a simple, green approach. By using different techniques (AFM, HR-TEM, SEM-EDS, FTIR, XRD, PL and UV-Vis) we investigated structural and optical properties of the new types of GQDs. We showed that GQDs functionalized with thiourea (GQDs-TU) completely lost the ability to produce singlet oxygen (1O2) upon photoexcitation while functionalization with urea (GQDs-U) improves the capability of GQDs to produce 1O2 upon the same conditions. Thus, presented GQDs modification with urea seems like a promising approach for the production of the efficient photosensitizer. On the opposite, GQDs-TU are efficient OH quencher. Due to high singlet oxygen production and low cytotoxicity below 100 µg/mL against HeLa cells, GQDs-U is a good candidate as an agent in photodynamic therapy at this concentration.

Graphene quantum dots inhibit T cell-mediated neuroinflammation in rats.

We investigated the therapeutic capacity of nano-sized graphene sheets, called graphene quantum dots (GQD), in experimental autoimmune encephalomyelitis (EAE), an animal model of immune-mediated central nervous system (CNS) damage. Intraperitoneally administered GQD (10 mg/kg/day) accumulated in the lymph node and CNS cells of Dark Agouti rats in which EAE was induced by immunization with spinal cord homogenate in complete Freund's adjuvant. GQD significantly reduced clinical signs of EAE when applied throughout the course of the disease (day 0-32), while the protection was less pronounced if the treatment was limited to the induction (day 0-7 post-immunization) or effector (from day 8 onwards) phase of the disease. GQD treatment diminished immune infiltration, demyelination, axonal damage, and apoptotic death in the CNS of EAE animals. GQD also reduced the numbers of interferon-γ-expressing T helper (Th)1 cells, as well as the expression of Th1 transcription factor T-bet and proinflammatory cytokines tumor necrosis factor, interleukin-1, and granulocyte-macrophage colony-stimulating factor in the lymph nodes and CNS immune infitrates. The protective effect of GQD in EAE was associated with the activation of p38 and p42/44 mitogen-activated protein kinases (MAPK) and Akt in the lymph nodes and/or CNS. Finally, GQD protected oligodendrocytes and neurons from T cell-mediated damage in the in vitro conditions. Collectively, these data demonstrate the ability of GQD to gain access to both immune and CNS cells during neuroinflammation, and to alleviate immune-mediated CNS damage by modulating MAPK/Akt signaling and encephalitogenic Th1 immune response.

Antibacterial photodynamic activity of carbon quantum dots/polydimethylsiloxane nanocomposites against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae.

Despite great efforts, the design of antibacterial surfaces is still a challenge. In this work, results of structural, mechanical, cytotoxic and antibacterial activities of hydrophobic carbon quantum dots/polydimethylsiloxane surfaces are presented. Antibacterial action of this surface is based on the generation of reactive oxygen species which cause bacteria damage by oxidative stress. At the same time, this surface was not cytotoxic towards the NIH/3T3 cells. Swelling-encapsulation-shrink method is applied for encapsulation of hydrophobic carbon quantum dots in medical grade silicone-polydimethylsiloxane. XPS and photoluminescence spectroscopy analyses confirm that hydrophobic carbon quantum dots have been encapsulated successfully into polydimethylsiloxane polymer matrix. Based on stress-strain test the improvement of mechanical properties of these nanocomposites is established. It is shown by electron paramagnetic resonance spectroscopy and luminescence method that nanocomposite generates singlet oxygen initiated by 470 nm blue light irradiation. Antibacterial testing shows the nanocomposite in the form of foil kills Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae and is very effective after only a 15 min irradiation.

Graphene oxide size and structure pro-oxidant and antioxidant activity and photoinduced cytotoxicity relation on three cancer cell lines.

Photoactive materials called photosensitizers can be used for treatment of different types of cancer in combination with light source. In this paper, we have investigated pro-oxidant and antioxidant potentials of four graphene based nanomaterials (graphene oxide-GO, graphene quantum dots-GQDs, carbon quantum dots-CQDs and N-doped carbon quantum dots-N-CQDs) depending on the presence/absence of visible light source. Structural and optical properties of these materials and their potentials for reactive oxygen species generation/quenching are investigated by applying different microscopy and spectroscopy techniques (transmission electron microscopy, FTIR, UV-Vis, photoluminescence, electron paramagnetic resonance). Results show that all types of quantum dots has pro-oxidant and antioxidant potentials whereas GO demonstrated only moderate antioxidant effect. The best free radical scavenger is CQDs sample in the absence of light. CQDs are the best singlet oxygen generator under blue light irradiation as well. To check photo-cytotoxicity of these materials, photo-cytotoxic concentrations of the GO, GQDs, CQDs and N-CQDs were determined for three cellular lines: human rhabdomyosarcoma (RD), cell line derived from human cervix carcinoma Hep2c (HeLa) and fibroblast cell line from murine (L2OB). Cytotoxicity test has indicated that all samples are much less photocytotoxic than cis-diamminedichloroplatinum (cis-DPP). The production method and doping of quantum dots affect the photodynamic activity of tested samples very much.

Photo-induced antibacterial activity of four graphene based nanomaterials on a wide range of bacteria.

Due to controversial reports concerning antibacterial activity of different graphene based materials it is very important to investigate their antibacterial action on a wide range of Gram-positive and Gram-negative bacteria. In this paper we have investigated the structure induced phototoxic antibacterial activity of four types of graphene based materials: graphene oxide (GO), graphene quantum dots (GQDs), carbon quantum dots (CQDs) and nitrogen doped carbon quantum dots (N-CQDs). Antibacterial activity was tested on 19 types of bacteria. It is found that nanometer-size CQDs and N-CQDs are the most potent agents whereas micrometer-size GO has very poor antibacterial activity. Electron paramagnetic resonance measurements confirmed photodynamic production of singlet oxygen for all types of used quantum dots. Detailed analysis has shown that N-CQDs are an excellent photodynamic antibacterial agent for treatment of bacterial infections induced by Enterobacter aerogenes (E. aerogenes), Proteus mirabilis (P. mirabilis), Staphylococcus saprophyticus (S. saprophyticus), Listeria monocytogenes (L. monocytogenes), Salmonella typhimurium (S. typhimurium) and Klebsiella pneumoniae.