Antibacterial susceptibility of bacteria isolated from burns and wounds of cancer patients

In this study 540 burns and wound swabs were collected from cancer patients of some Egyptian hospitals. The single infection was detected from 210, and 70 cases among wounded and burned patients, while mixed infection was 30 and 45, respectively. We recovered where 60 isolates of Pseudomonas aeruginosa, 60 isolates of Staphylococcus aureus, 7 isolates of Staphylococcus epidermidis, 4 isolates of Streptococcus pyogenes, 25 isolates of Escherichia coli, 23 isolates of Klebsiella pneumoniae and 27 isolates of Proteus vulgaris from 355 burn and surgical wound infections . All bacterial isolates showed high resistance to the commonly used β-lactams (amoxycillin, cefaclor, ampicillin, vancomycin, amoxicillin/clavulonic), and low resistance to imepenim and ciprofloxacin. Plasmid analysis of six multidrug resistant and two susceptible bacterial isolates revealed the same plasmid pattern. This indicated that R-factor is not responsible for the resistance phenomenon among the isolated opportunistic bacteria. The effect of ultraviolet radiation on the isolated bacteria was studied.     

Distribution and types of bacteria isolated from an inland saltern

The physico-chemical characteristics and bacterial populations of an inland saltern were studied. The well water leading into the ponds of the saltern differed from sea water in its total salinity (18 % (w/v)) and had lower Mg²⁺ and SO₄²⁻ contents and much higher contents of Cl⁻, Ca²⁺ and K⁺A high proportion of halotolerant microorganisms were isolated, although marine bacteria were not found. Most of the halophilic strains isolated appeared to be typical moderate halophiles, and included six groups: Vibrio (39 %), Deleya-Pseudomonas (28 %), Acinetobacter (6.5 %), Flavobacterium (6.5 %), Paracoccus (1.5 %), Planococcus (1.5 %) and non-classified (17 %). All extreme halophiles could be assigned to Hallobacterium (31 %) and Halococcus (68 %).     

Biosorption of heavy metals by bacteria isolated from activated sludge

Twelve aerobic bacteria from activated sludge were isolated and identified. These included both Gram-positive (e.g., Bacillus) and Gram-negative (e.g., Pseudomonas) bacteria. The biosorption capacity of these strains for three different heavy metals (copper, nickel, and lead) was determined at pH 5.0 and initial metal concentration of 100 mg/L. Among these 12 isolates, Pseudomonas pseudoalcaligenes was selected for further investigation owing to its high metal biosorption capacity. The lead and copper biosorption of this strain followed the Langmuir isotherm model quite well with maximum biosorption capacity (q _max) reaching 271.7mg of Pb²⁺/g of dry cell and 46.8 mg of Cu²⁺/g of dry cell at pH 5.0. Study of the effect of pH on lead and copper removal indicated that the metal biosorption increased with increasing pH from 2.0 to 7.0. A mutual inhibitory effect was observed in the lead-copper system because the presence of either ion affected the sorption capacity of the other. Unequal inhibitions were observed in all the nickel binary systems. The increasing order of affinity of the three metals toward P. pseudoalcaligenes was Ni<Cu<Pb. The metal biosorptive potential of these isolates, especially P. pseudoalcaligenes, may have possible applications in the removal and recovery of metals from industrial effluents.     

Molecular characterization of bacteria isolated from waste electrical transformer oil

Electrical transformer oil (ETO) includes as dielectric fluids hazardous compounds such as PAHs and sometimes PCBs, which are highly toxic and resistant to degradation. Three species of bacteria, belonging to Acinetobacter lwoffii, Bacillus amyloliquefaciens, and Bacillus pumilus, were isolated from waste ETO. Phenotypic and molecular assays revealed a high potential of A. lwoffii for catabolism of phenanthrene and ETO as a sole carbon and energy source. This article reports for the first time the isolation, identification, and characterization of bacterial diversity hidden in ETO. The article is published in the original.     

Microbial production of polyhydroxyalkanoates by bacteria isolated from oil wastes

A Gram-positive coccus-shaped bacterium capable of synthesizing higher relative molecular weight (M _r), polyhydroxybutyrate (PHB) was isolated from sesame oil and identified as Staphylococcus epidermidis (by Microbial ID, Inc., Newark, NJ). The experiment was conducted by shake flask fermentation culture using media containing fructose. Cell growth up to a dry mass of 2.5 g/L and PHB accumulation up to 15.02% of cell dry wt was observed. Apart from using single carbohydrate as a sole carbon source, various industrial food wastes including sesame oil, ice cream, malt, and soya wastes were investigated as nutrients for S. epidermidis to reduce the cost of the carbon source. As a result, we found that by using malt wastes as nutrient for cell growth, PHB accumulation of S. epidermidis was much better than using other wastes as nutrient source. The final dried cell mass and PHB production using malt wastes were 1.76 g/L and 6.93% polymer/cells (grams/gram), and 3.5 g/L and 3.31% polymer/cells (grams/gram) in shake flask culture and in fermentor culture, respectively. The bacterial polymer was characterized by ¹H-nuclear magnetic resonance (NMR), ¹³C-NMR, Fourier transform infrared, and differential scanning calorimetry. The results show that with different industrial food wastes as carbon and energy sources, the same biopolymer (PHB) was obtained. However, the use of sesame oil as the carbon source resulted in the accumulation of PHB with a higher melting point than that produced from other food wastes as carbon sources by this organism under similar experimental conditions.     

Action of chitosan against Xanthomonas pathogenic bacteria isolated from Euphorbia pulcherrima

The antibacterial activity and mechanism of two kinds of chitosan were investigated against twelve Xanthomonas strains recovered from Euphorbia pulcherrima. Results indicated that both chitosans markedly inhibited bacterial growth based on OD loss. Furthermore, the release of DNA and RNA from three selected strains was increased by both chitosans. However, the release of intracellular proteins was inhibited by both chitosans at different concentration and incubation times, except chitosan A at 0.1 mg/mL for 0.5 h incubation and 0.2 mg/mL for 2.0 h incubation increased the release of proteins, indicating the complexity of the interaction and cell membranes, which was affected by incubation time, bacterial species, chitosan type and concentration. Transmission electron microscopic observations revealed that chitosan caused changes in protoplast concentration and surface morphology. In some cells, the membranes and walls were badly distorted and disrupted, while other cells were enveloped by a thick and compact ribbon-like layer. The contrary influence on cell morphology may explain the differential effect in the release of material. In addition, scanning electron microscope and biofilm formation test revealed that both chitosans removed biofilm biomass. Overall, this study showed that membrane and biofilm play an important role in the antibacterial mechanism of chitosan.     

Dereplication and targeted isolation of bioactive sulphur compound from bacteria isolated from a hydrothermal field

Marine micro-organisms in the deep-sea hydrothermal vent systems are considered as potential sources of bioactive natural products. Sixteen bacterial strains were isolated from a deep-sea hydrothermal field and screened for bioactive metabolism studies. After the strains were subjected to bioactive testing at different culture media, chemical dereplication by HPLC coupled to high-resolution mass spectrometer was performed to analyse or determine the main secondary metabolisms in those strains. Strain 06204 was large-scale fermented with relative optimal media, for isolating the desired sulphur compound. Butyrolactone I 3-sulphate was isolated and structurally identified from the extract, guided by dereplication and showed moderate antivirus activities against H3N2 and EV71 viruses. Our study suggests that deep-sea hydrothermal bacteria are good sources of sulphur natural products. Meanwhile, the described approach, mainly bioactive screening, dereplication and targeted isolation, is effective and efficient to discover interesting bioactive compounds in hydrothermal bacteria.     

Gram-negative bacteria viable in ultrapure water: identification of bacteria isolated from ultrapure water and effect of temperature on their behavior

This study describes the effect of temperature on the behavior of bacteria viable in ultrapure water and the contamination of ultrapure water by bacteria. Three species of bacteria were isolated from ultrapure water (total organic carbon, 60 ppb and 5 ppb; effluent resistivity > 18 MΩ cm at 25°C) and identified by morphological and physiological characteristics. The three isolates were incubated in water for injection and PYG broth to check the growth profile at various temperatures. In PYG broth, temperature influenced the behavior of bacteria directly; however, it did not in water for injection. By checking both viable and non-viable bacterial numbers and endotoxin concentration in pure water, the water was found to be contaminated with non-viable bacteria and newly generated endotoxins besides viable bacteria. A column treatment, a mixed bed of fully regenerated strong acid cation exchange resin (SACER) and strong base anion exchange resin (SBAER), was used to remove bacteria from pure water. Bacteria could not grow on the surfaces of ion exchange resins in the mixed bed. The removal of bacteria was more effective as pure water was circulated through the mixed bed more rapidly.     

Conversion of arsenobetaine to dimethylarsinic acid by arsenobetaine-decomposing bacteria isolated from coastal sediment

Arsenobetain [(CH₃)₃As⁺CH₂COO^-]-containing growth media (1/5 ZoBell 2216E and solution of inorganic salts) were inoculated with two bacterial strains, which were isolated from a coastal sediment and identified as members of the Vibro-Aeromonas group, and incubated under aerobic and anaerobic conditions. Arsenobetaine was converted to a metabolite only under aerobic conditions. This arsenic metabolite was identified as dimethylarsinic acid [(CH₃)₂AsOOH] by hydride generation/cold trap/GC MS/SIM analysis and high-performance liquid-chromatographic behaviour. The conversion pattern shown by these arsenobetaine-decomposing bacteria (that is, arsenobetaine → dimethylarsinic acid) was fairly different from that shown by the addition of sediment itself as the source of arsenobetaine-decomposing micro-organisms (that is, arsenobetaine → trimethylarsine oxide → inorganic arsenic). This result suggests to us that various micro-organisms, including the arsenobetaine-decomposing bacteria isolated in this study, participate in the degradation of arsenobetaine in marine environments.     

Antibacterial activity of an aqueous extract of Petroselinum crispum leaves against pathogenic bacteria isolated from patients with burns infections in Al-najaf Governorate, Iraq

The purpose of this study was to investigate, by use of the agar well diffusion method, the ability of cold-water and hot-water extracts of Petroselinum crispum leaves to inhibit bacteria isolated from patients with burns infections. The results revealed that 250 mg/ml of the hot-water extract was the more effective inhibitor of the growth of P. aeruginosa. The inhibition zone diameter of 29.667 mm was significantly different (P < 0.05) from that for nitrofurantoin, chosen as positive control. From the overall results obtained it is evident that the plant screened has anti-bacterial activity against some bacteria associated with burns infections.     

A general framework for inhibitor resistance in protein kinases

Protein kinases control virtually every aspect of normal and pathological cell physiology and are considered ideal targets for drug discovery. Most kinase inhibitors target the ATP binding site and interact with residue of a hinge loop connecting the small and large lobes of the kinase scaffold. Resistance to kinase inhibitors emerges during clinical treatment or as a result of in vitro selection approaches. Mutations conferring resistance to ATP site inhibitors often affect residues that line the ATP binding site and therefore contribute to selective inhibitor binding. Here, we show that mutations at two specific positions in the hinge loop, distinct from the previously characterized "gatekeeper," have general adverse effects on inhibitor sensitivity in six distantly related kinases, usually without consequences on kinase activity. Our results uncover a unifying mechanism of inhibitor resistance of protein kinases that might have widespread significance for drug target validation and clinical practice.     

A chemiluminescence study on degradation of gelatine: Biodegradation by bacteria and fungi isolated from cinematographic films

Chemiluminescence (CL) has become a sensitive tool for the study of polymer degradation, induced by exposure to various factors, such us heat, UV-light and oxygen. In this paper, the results obtained with this technique in the study of gelatine samples hydrolytically degraded under sterilisation conditions are presented. Also, photographic gelatine exposed to bacterial and fungal degradations, in water solution and under controlled conditions, have been study by the chemiluminescence emission of their corresponding films and the biodegradation extent was determined by viscosity. The bacteria and fungi employed in this work have been isolated from cinematographic films in a previous work.The high intensities of chemiluminescence emission obtained for gelatines biodegraded by bacteria and fungi, in aqueous solution at 37 and 25 °C, respectively, are different to those obtained in the thermal degradation. The hydrolytic degradation mechanism is through a cleavage of the peptide bond of the protein without significant oxidation of the material. In contrast, biodegradation by bacteria and fungi at low temperatures decreases the molecular weight of the gelatine (viscosity) by the enzymatic activity but, also, produces an important oxidation in the material due to the reactive oxygen species (ROS) generated in the microbial metabolism.     

Roimatacene: an antibiotic against Gram-negative bacteria isolated from Cystobacter ferrugineus Cb G35 (Myxobacteria)

Roimatacene (1) was isolated from the myxobacterium Cystobacter ferrugineus strain Cb G35 in a bioactivity-guided process, by following the antimicrobial activity against Escherichia coli. Since 1 was extremely sensitive to oxygen, a protective isolation and handling protocol was developed, by utilizing the free radical scavenger 4-ethoxyphenol. The structure of 1 was determined by HRMS, 1D and 2D NMR spectroscopy and chemical derivatization to acetonides and Mosher esters to finally establish the absolute configuration. Methionine and acetate were identified as building blocks in the biosynthesis of 1 by feeding experiments with differently (13)C-labeled precursors. The antimicrobial activity of 1 was determined in a broad screening revealing 1 to inhibit several Gram-negative bacteria.     

Berberine and itraconazole are not synergistic in vitro against Aspergillus fumigatus isolated from clinical patients

The incidence of Aspergillus fumigatus infections has become more frequent as a consequence of widespread immunosuppression. At present, the number of available antifungal agents in the clinic is limited, and most of them, such as itraconazole (ICZ), are toxic and show resistance. Berberine (BER) is a plant alkaloid used in the clinic mainly for alimentary infections. We have used BER and ICZ to measure in vitro resistance in A. fumigatus isolated from clinical patients. The minimum inhibitory concentration ranges of BER and ICZ were 4-256 and 0.031-0.250 μg/mL, respectively. In addition, against A. fumigatus IFM 40808 strain, the MIC?? values of BER and ICZ were 8 and 0.125 μg/mL. Using this strain, we compared the giant colonies with or without BER, and concluded that BER could restrain A. fumigatus mycelial growth and conidial pigment production. Combinations of the two drugs were also tested by the checkerboard assay to identify any functional interactions between them. Thirty-two out of 42 isolates had FICI values > 4.0, indicating that two drugs were mutually antagonistic. In conclusion, it is not advised that BER and ICZ be used in the clinic at the same time. Our results indicated that BER may inhibit A. fumigatus through the ergosterol biosynthesis pathway, like ICZ.     

Capillary electrophoretic profiling and pattern recognition analysis of urinary nucleosides from thyroid cancer patients

Metabolic profiling analysis by capillary electrophoresis (CE) was combined with pattern recognition methods to see some correlation between urinary nucleoside levels and thyroid cancer. A total of 15 nucleosides were identified in urines from 12 female thyroid cancer patients and 12 healthy females studied. From the scatter plot evaluation, inosine showed the highest estimated diagnostic power with ca. 97.725% confidence level, followed by N²-methylguanosine. Star symbol graphs showed differences in levels of both minor and major nucleosides between cancer and normal groups more efficiently, compared with histogram. The stepwise discriminant analysis (SDA) selected N²-methylguanosine, N²,N²-dimethylguanosine and 1-methylguanosine as the most discriminating variables between thyroid cancer and normal groups. The canonical discriminant analysis (CDA) correctly classified all urine specimens studied into two separate clusters of cancer and normal groups in a canonical plot. The principal component analysis (PCA) distinguished cancer patients from normal controls in a principal component plot. The cluster analysis (CA) yielded a dendrogram displaying group separation without any single wrong linkage.     

Molecular characterization and antioxidant assay of pigment producing bacteria,Sphingomonas paucimobilis and Microbacterium arborescens isolated from fresh water sediments

Abstract

This study focuses on isolation of pigment producing bacteria from fresh water sediment. The isolated bacteria were grown in nutrient broth and the maximum absorbance of 2.512 was obtained for the extracted pigment at 500 nm. The effective strains were optimized, pH 11 and temperature 30 °C was found to be more favorable for its maximum growth. The isolates were identified based on their molecular characterestics as Microbacterium arborescens and Sphingomonas paucimobilis, molecular size of the amplified 16S rRNA gene sequence was found to be approximately 1270 and 765 bp respectively. The antioxidant property of the pigment was analyzed using DPPH and ABTS assay. The IC₅₀ value of Microbacterium arborescens was higher in all the three assays in comparison with Sphingomonas paucimobilis. The extracted pigment was characterized for the presence of compounds using GC-MS and FTIR analysis to determine the functional groups. As the pigment obtained from M. arborescens had shown better antioxidant activity it may be used as colorant in food industrial applications.