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- Acute fibrinous organising pneumonia: a manifestation of trimethoprim-sulfamethoxazole pulmonary toxicity. [Journal Article]
- BMJ Case Rep 2014.
A 50-year-old man was treated with trimethoprim-sulfamethoxazole (TMP-SMX) for acute arthritis of his right big toe. Within a few days, he developed dyspnoea, hypoxaemia and diffuse pulmonary infiltrates. Symptoms improved with discontinuation of the antibiotic but worsened again with its reintroduction. An open lung biopsy was performed. We describe the workup performed and the factors that pointed to a final diagnosis of TMP-SMX-related pulmonary toxicity in the form of acute fibrinous organising pneumonia.
- Operation of integrated sequencing batch membrane bioreactor treating dye-containing wastewater at different SRTs: study of overall performance and fouling behavior. [JOURNAL ARTICLE]
- Environ Sci Pollut Res Int 2014 Oct 30.
The main aim of the present work was to study the overall performance and the fouling behavior of the integrated sequencing batch membrane bioreactor (SBMBR) treating synthetic dye-containing wastewater at different sludge retention times (SRTs) of 10, 40, and 160 days. For this reason, the removal efficiencies of color and chemical oxygen demand (COD) and the membrane fouling rates as well as the main sludge characteristics including extracellular polymeric substances (EPS), soluble microbial products (SMP), particle size distribution (PSD), and apparent viscosity were evaluated during the operation time of three SBMBRs. According to the obtained results, the decolorization efficiency was found to increase with increasing the SRT while the COD removal efficiency was similarly high (94-97 %) in all SBMBRs regardless of SRT change. The rate of rise of transmembrane pressure (TMP) was much lower in the SBMBR operating at SRT of 160 days compared with the two other SBMBRs. Cake development on the membrane surface was recognized as the predominant fouling mechanism in three SBMBRs. Among the stated sludge properties, specific EPS and uniformity coefficient of the particle size distribution were suggested to be the controlling factors of the membrane fouling rate in three SBMBRs. During the operation at prolonged SRT (160 days in this study), better decolorization efficiency and lower biofouling rate were obtained in SBMBR system.
- Characterization of trimethoprim-sulfamethoxazole resistance genes and their relatedness to class 1 integron and insertion sequence common region in gram negative bacilli. [JOURNAL ARTICLE]
- J Microbiol Biotechnol 2014 Oct 28.
Trimethoprim-sulfamethoxazole (TMP-SMX) has been used for the treatment of urinary tract infectinons but increasing resistance to TMP-SMX has been reported. In this study, we analyzed TMP-SMX resistance genes and their relatedness with integrons and insertion sequence common regions (ISCRs) in uropathogenic gram negative bacilli. Consecutive non-duplicate TMP-SMX non-susceptible clinical isolates of E. coli, K. pneumoniae, Acinetobacter spp., and P. aeruginosa were collected from urine. Minimal inhibitory concentration was determined by Etest. TMP-SMX resistance genes (sul and dfr), integrons and ISCRs were analyzed by PCR and sequencing. A total of 45 E. coli (37.8%), 15 K. pneumoniae (18.5%), 12 Acinetobacter spp. (70.6%), and 9 Pseudomonas aeruginosa (30.0%) isolates were found to be resistant to TMX- SMX. Their MICs were all over 640. In E. coli and K. pneumonia, sul1 and dfr genes were highly prevalent in relation with integron1. Sul3 gene was detected in E. coli. In P. aeruginosa and Acinetobacter spp., only sul1 was prevalent in relation with class 1 integron, however, dfr was not detected and sul2 was less prevalent than in Enterobacteriaceae. ISCR1 and/or ISCR2 were detected in E. coli, K. pnuemoniae, and Acinetobacter spp. but relatedness with TMP-SMX resistance genes was not prominent. ISCR14 was detected in 6 isolates of E. coli. In conclusion, resistance mechanisms for TMX-SMX were different between Enterobacteriaceae and glucose non-fermenting gram negative bacilli. Class 1 integron was widely disseminated in uropathogenic gram negative baciili, so adoption of prudent use of antimicrobial agents and establishment of surveillance system are needed.
- Synergistic Interaction of Vancomycin with Different Antibiotics in Escherichia coli: Trimethoprim and Nitrofurantoin Display Strong Synergies with Vancomycin in Wild-type E.coli. [JOURNAL ARTICLE]
- Antimicrob Agents Chemother 2014 Oct 27.
Gram-negative bacteria are normally resistant to the antibiotic vancomycin (VAN), which cannot significantly penetrate the outer membrane. We used Escherichia coli mutants that are partially sensitive to VAN to study synergies between VAN and 10 other antibiotics representing 6 different functional categories. We detected strong synergies with VAN and nitrofurantoin (NIT) and with VAN and trimethoprim (TMP), and moderate synergies with other drugs, such as aminoglycosides. These synergies are powerful enough to show activity of VAN in wild-type E. coli at concentrations of VAN as low as 6.25 μg/ml. This suggests that a very small percentage of exogenous VAN does enter E. coli, but normally has insignificant effects on growth inhibition or cell killing. We used the results of pair-wise interactions with VAN and the other 10 antibiotics tested to place VAN into a functional category of its own, as previously defined by Yeh, Tschumi and Kishony (1).
- Study on the interaction between ligustrazine and 12-tungstophosphoric acid using resonance Rayleigh scattering and resonance nonlinear scattering spectra, and its analytical applications. [JOURNAL ARTICLE]
- Luminescence 2014 Oct 24.
In an HCl medium (pH 1.5), ligustrazine (2,3,5,6-tetramethylpyrazine, TMP) reacted with 12-tungstophosphoric acid (TP) to form a 3 : 1 ion-association complex. As a result, the intensities of resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering (FDS) were greatly enhanced and new scattering spectra appeared. The maximum RRS, SOS and FDS wavelengths of the ion-association complexes were located at 379, 738 and 395 nm, respectively. The scattering intensity increments (ΔIRRS , ΔISOS and ΔIFDS ) were directly proportional to the concentration of ligustrazine within certain ranges. The detection limits (3σ) of RRS, SOS and FDS were 1.6, 3.2 and 2.8 ng/mL. Optimal conditions for the RRS method and factors influencing the method were discussed, and the structure of the ion-association complex and the reaction mechanism were investigated. Transmission electron microscopy (TEM) was used to characterize the structures of the ion-association complex. Based on the ion-association reaction and its spectral response, a rapid, simple and sensitive RRS method for the determination of TMP was developed. It was applied to the determination of TMP in tablet and urine samples with satisfactory results. Copyright © 2014 John Wiley & Sons, Ltd.
- Selective phenol methylation to 2,6-dimethylphenol in a fluidized bed of iron-chromium mixed oxide catalyst with o-cresol circulation. [Journal Article]
- Chem Cent J 2014; 8(1):51.
2,6-dimethylphenol (2,6-DMP) is a product of phenol methylation, especially important for the plastics industry. The process of phenol methylation in the gas phase is strongly exothermic. In order to ensure good temperature equalization in the catalyst bed, the process was carried out using a catalyst in the form of a fluidized bed - in particular, the commercial iron-chromium catalyst TZC-3/1.Synthesis of 2,6-dimethylphenol from phenol and methanol in fluidized bed of iron-chromium catalyst was carried out and the fluidization of the catalyst was examined. Stable state of fluidized bed of iron-chromium catalyst was achieved. The measured velocities allowed to determine the minimum flow of reactants, ensuring introduction of the catalyst bed in the reactor into the state of fluidization. Due to a high content of o-cresol in products of 2,6-dimethylphenol synthesis, circulation in the technological node was proposed. A series of syntheses with variable amount of o-cresol in the feedstock allowed to determine the parameters of stationary states.A stable work of technological node with o-cresol circulation is possible in the temperature range of350-380°C, and o-cresolin/phenolin molar ratio of more than 0.48. Synthesis of 2,6-DMP over the iron-chromium catalyst is characterized by more than 90% degree of phenol conversion. Moreover, the O-alkylation did not occur (which was confirmed by GC-MS analysis). By applying o-cresol circulation in the 2,6-DMP process, selectivity of more than 85% degree of 2,6-DMP was achieved. The participation levels of by-products: 2,4-DMP and 2,4,6-TMP were low. In the optimal conditions based on the highest yield of 2,6-DMP achieved in the technological node applying o-cresol circulation, there are 2%mol. of 2,4-DMP and 6%mol. of 2,4,6-TMP in the final mixture, whereas 2,4,6-TMP can be useful as a chain stopper and polymer's molar mass regulator during the polymerization of 2,6-DMP.
- Enzymatic synthesis of poly(catechin)-antibiotic conjugates: an antimicrobial approach for indwelling catheters. [JOURNAL ARTICLE]
- Appl Microbiol Biotechnol 2014 Oct 21.
Biofilm formation in urinary indwelling catheters is one of the most critical issues that patients face. Catheters were coated with poly(catechin)-antibiotic conjugates with enhanced antimicrobial properties. Catechin was conjugated with two antibiotics, namely trimethoprim (TMP) and sulfamethoxazole (SMZ) via activation with N,N'-disuccinimidyl carbonate (DSC) and subsequent coupling to molecules containing α-amine moieties. Silicone and polyurethane catheters were functionalized in situ through laccase oxidation of catechin-antibiotic conjugates. Four antimicrobial coatings were produced, namely with poly(catechin), poly(catechin)-TMP, poly(catechin)-SMZ and poly(catechin)-TMP-SMZ. The bacterial adhesion reduction was tested on the functionalized devices using gram-negative and gram-positive strains. The most significant reduction in adhesion was observed with poly(catechin)-TMP (gram-negative -85 % and gram-positive -87 %) and with poly(catechin)-TMP-SMZ (gram-negative -85 % and gram-positive -91 %). The cytotoxicity to mammalian cells was tested by indirect contact for 5 days and revealed that all the tested coatings supported more than 90 % of viable cells. A promising approach for the increase of the indwelling catheter lifespan was developed aiming to reduce catheter-associated chronic infections.
- Effects of filtration modes on membrane fouling behavior and treatment in submerged membrane bioreactor. [JOURNAL ARTICLE]
- Bioresour Technol 2014 Sep 20.:391-395.
Relaxation or backwashing is obligatory for effective operation of membrane module and intermittent aeration is helpful for nutrients removal. This study was performed to investigate effects of different filtration modes on membrane fouling behavior and treatment in membrane bioreactor (MBR) operated at three modes i.e., 12, 10 and 8min filtration and 3, 2, and 2min relaxation corresponding to 6, 5 and 4cycles/hour, respectively. Various parameters including trans-membrane pressure, specific cake resistance, specific oxygen uptake rate, nutrients removal and sludge dewaterability were examined to optimize the filtration mode. TMP profiles showed that MBR(8+2) with 8min filtration and 2min relaxation reduced the fouling rate and depicted long filtration time in MBR treating synthetic wastewater. MBR(12+3) was more efficient in organic and nutrients removal while denitrification rate was high in MBR(8+2).
- Isolation and antibiotic susceptibility of Shigella species from stool samples among hospitalized children in Abadan, Iran. [Journal Article]
- Gastroenterol Hepatol Bed Bench 2014; 7(4):218-23.
The aim of this study was to determine the incidence of Shigella species and their antimicrobial susceptibility patterns in hospitalized children with Shigellosis in Abadan, Iran.Shigellosis is caused by different species of Shigella and one of the most common causes of diarrhea in children. This disease is endemic in many developing countries including Iran.This prospective cross sectional study was conducted in a teaching hospital in Abadan, Iran during June 2011 to May 2013. Stool specimens were collected from pediatric age group. All isolates were confirmed as Shigella species by biochemical and serologic tests. Antibiotic sensitivity pattern of these isolates was studied by disk diffusion Method.Among all 705 stool samples, 36 (5.1%) yielded Shigella. Of cases, 392 (55.6%) were girl and 313 (44.4%) were boy. The most common Shigella isolates were S. flexneri (n=19, 52.7%) followed by S. sonnei (n=11, 30.5%), S. boydii (n=4, 11.1%) and S. dysenteriae 2(5.5%). Of the Shigella isolates, 47.2% showed resistance to two or more antimicrobial agents. Resistance pattern against various antimicrobials were as follows: trimethoprim-sulphamethoxazole (80.5%), ampicillin (63.8%), tetracycline (58.3%), chloramphenicol (33.3%), nalidixic acid (27.7%), and cefixime (16.6%). There was no resistance against ciprofloxacin and ceftriaxone.The most common isolates were S. flexneri followed by S. Sonnei. There was no antibiotic resistance against ciprofloxacin and ceftriaxone. TMP-SMZ showed highest resistance pattern.
- Efficacy of caspofungin, a 1,3-β-D-glucan synthase inhibitor, on Pneumocystis carinii pneumonia in rats. [JOURNAL ARTICLE]
- Med Mycol 2014 Oct 6.
Pneumocystis carinii pneumonia (PcP) is a common and potentially fatal opportunistic infection in immunosuppressed patients, and the standard trimethoprim-sulfamethoxazole (TMP-SMZ) treatment has serious side effects. The cell wall of the causative fungal pathogen is enriched in 1-3-β-D-glucan, providing an alternative therapeutic target. We directly compared the efficacy of the 1,3-β-D-glucan synthase inhibitor caspofungin to TMP-SMZ for promoting survival and reducing lung cyst number during the early phase of treatment in a rat model of PcP. Rats were immunosuppressed using dexamethasone for 8 weeks and PcP infection confirmed in test animals by lung print smear. The remaining rats were randomly divided into three control groups, a baseline group and two observed for 7 or 14 days, two caspofungin groups treated intravenously for 7 or 14 days (1 mg/kg/d), and 2 TMP-SMZ positive control groups treated by oral gavage for 7 or 14 days (300 mg/kg/d). Mortality was markedly reduced by both caspofungin and TMP-SMZ after 14 days (caspofungin: 20.0%, TMP-SMZ: 13.3%, Control: 40.0%). Body weight gain in caspofungin-treated rats after 7 (3.04 ± 3.54%) and 14 (4.27 ± 2.79%) days was similar to that in TMP-SMZ-treated rats (3.35 ± 1.88% and 5.85 ± 2.78%, respectively), whereas untreated controls showed weight loss. Lung weight to body weight ratio, and mean cyst number per 50 microscopic fields were significantly lower (all P < 0.05) in caspofungin-treated rats than untreated controls at both 7 and 14 days, and similar to those in the TMP-SMZ-treated rats (all P > 0.05 vs. caspofungin). Caspofungin exhibited similar efficacy to TMP-SMZ for enhancing survival and reducing lung edema and cyst load in a rat model of PcP, suggesting potential clinical utility against PcP.