Rutin-coated zinc oxide nanoparticles: a promising antivirulence formulation against pathogenic bacteria.

The use of engineered nanoparticles against pathogenic bacteria has gained attention. In this study, zinc oxide nanoparticles conjugated with rutin were synthesized and their antivirulence properties against Pseudomonas aeruginosa and Staphylococcus aureus. The physicochemical characteristics of ZnO-Rutin NPs were investigated using SEM, FT-IR, XRD, DLS, EDS, and zeta potential analyses. Antimicrobial properties were evaluated by well diffusion, microdilution, growth curve, and hemolytic activity assays. The expression of quorum sensing (QS) genes including the lasI and rhlI in P. aeruginosa and agrA in S. aureus was assessed using real-time PCR. Swimming, swarming, twitching, and pyocyanin production by P. aeruginosa were evaluated. The NPs were amorphous, 14-100 nm in diameter, surface charge of -34.3 mV, and an average hydrodynamic size of 161.7 nm. Regarding the antibacterial activity, ZnO-Rutin NPs were more potent than ZnO NPs and rutin, and stronger inhibitory effects were observed on S. aureus than on P. aeruginosa. ZnO-Rutin NPs inhibited the hemolytic activity of P. aeruginosa and S. aureus by 93.4 and 92.2%, respectively, which was more efficient than bare ZnO NPs and rutin. ZnO-Rutin NPs reduced the expression of the lasI and rhlI in P. aeruginosa by 0.17-0.43 and 0.37-0.70 folds, respectively while the expression of the agrA gene in S. aureus was decreased by 0.46-0.56 folds. Furthermore, ZnO-Rutin NPs significantly reduced the swimming and twitching motility and pyocyanin production of P. aeruginosa. This study demonstrates the antivirulence features of ZnO-Rutin NPs against pathogenic bacteria which can be associated with their QS inhibitory effects.

Diclofenac-loaded PLGA nanoparticles downregulate LasI/R quorum sensing genes in pathogenic P. aeruginosa isolates.

Poly(lactic-co-glycolic acid) (PLGA) is a biocompatible polymer that can gradually and consistently release drugs in a controlled manner. In this study, diclofenac sodium-loaded PLGA nanoparticles (DS-PLGA NPs) were produced by solvent evaporation technique and characterized using SEM, DLS, and zeta potential analyses. The antibacterial and antivirulence potential of DS-PLGA NPs against P. aeruginosa strains were examined using broth microdilution, crystal violet staining, hemolysis, and twitching quantification assays. Furthermore, the expression of the quorum sensing (QS) genes, lasI and lasR in P. aeruginosa strains after treatment with 1/2 MIC of DS-PLGA NPs was assessed using real-time PCR. SEM imaging of the synthesized NPs exhibited that the NPs have a spherical structure with a size range of 60-150 nm. The zeta potential of the NPs was - 15.2 mV, while the size of the particles in the aquatic environment was in a range of 111.5-153.8 nm. The MIC of prepared NPs against various strains of P. aeruginosa ranged from 4.5 to 9 mg/mL. Moreover, exposure of bacteria to sub-MIC of DS-PLGA NPs significantly down-regulated the expression of the lasI and lasR genes to 0.51- and 0.75-fold, respectively. Further, prepared NPs efficiently reduced the biofilm formation of P. aeruginosa strains by 9-27%, compared with the controls. Besides, DS-PLGA NPs showed considerable attenuation in bacterial hemolytic activity by 32-88% and twitching motility by 0-32.3%, compared with untreated cells. Overall, the present work exhibited the anti-QS activity of DS-PLGA NPs, which could be a safe and useful approach for treating P. aeruginosa infections.

In vitro and in silico assessment of anti-quorum sensing activity of Naproxen against Pseudomonas aeruginosa.

Serious infections caused by Pseudomonas aeruginosa are usually related to quorum sensing (QS)-dependent virulence factors. Hence, QS inhibition is a promising approach to overcoming P. aeruginosa infections. This study aimed to investigate the effect of naproxen on biofilm formation and QS-related virulence traits of P. aeruginosa. Furthermore, the anti-QS potential of naproxen was evaluated using real-time PCR and molecular docking analysis. Our findings supported the anti-QS activity of naproxen, as evidenced by down-regulation of the lasI and rhlI genes expression as well as the attenuation of bacterial protease, hemolysin, pyocyanin, biofilm, and motility. Additionally, the high binding affinity of naproxen with QS regulatory proteins was determined in the molecular docking simulation. Altogether, these findings suggest that naproxen has a promising potential in inhibiting QS-associated traits of P. aeruginosa.

Antibacterial potential and cytotoxic activity of iron oxide nanoparticles conjugated with thymol (Fe3O4@Glu-Thymol) on breast cancer cells and investigating the expression of BAX, CASP8, and BCL-2 genes.

The use of metal nanoparticles (NPs) conjugated with natural herbal molecules in biomedical applications has been growing. In this work, we synthesized Iron oxide NPs conjugated with thymol (Fe3O4@Glu-Thymol) and investigated their antibacterial and anticancer potentials. Physicochemical features of the NPs were studied by FT-IR, EDS-mapping, XRD, DLS, zeta potential, and electron microscopy. The antibacterial activity of the NPs against Pseudomonas aeruginosa and anticancer activity for breast cancer cells was investigated by broth microdilution and MTT and flow cytometry assays, respectively. The expression of apoptosis signaling genes in breast cancer cells that were treated with the NPs was studied by qPCR assay. The NPs were spherical, in a size range of 40-66 nm, without impurities, and with zeta potential and hydrodynamic size of - 23 mV and 185 nm, respectively. Moreover, the FT-IR and XRD assays confirmed the proper synthesis of Fe3O4 and conjugation with thymol. The minimum inhibitory concentration of the NPs for P. aeruginosa strains was 64-128 µg/mL. Our results showed that Fe3O4@Glu-Thymol was considerably more toxic for breast cancer cells than normal human cells and the 50% inhibitory concentration were 90.4 and 322 µg/mL, respectively. Upon treating breast cancer cells with the NPs the frequency of cell apoptosis increased by 18.9%. Also, the expression of the BAX and CASP8 genes in NPs treated cells significantly increased by 1.75 and 2.25 folds, respectively while the BCL-2 gene remained almost constant. This study reveals that Fe3O4@Glu-Thymol has considerable potential to be used in biomedical fields.

Effect of samarium oxide nanoparticles on virulence factors and motility of multi-drug resistant Pseudomonas aeruginosa.

Biofilm formation and quorum sensing (QS) dependent virulence factors are considered the major causes of the emergence of drug resistance, therapeutic failure and development of Pseudomonas aeruginosa infections. This study aimed to investigate the effects of samarium oxide nanoparticles (Sm2O3NPs) on biofilm, virulence factors, and motility of multidrug-resistant P. aeruginosa. Sm2O3NPs were synthesized using curcumin and characterized by Transmission Electron Microscopy, X-ray diffractometer, Field Emission Scanning Electron Microscopy, and Energy-dispersive X-ray spectroscopy. Minimum inhibitory concentration (MIC) was determined using broth microdilution method. The antibiofilm potential of Sm2O3NPs was also evaluated by crystal violet staining and light microscopy examination. Then, the effect of sub-MICs concentrations of Sm2O3NPs on the proteolytic and hemolytic activities of P. aeruginosa was investigated. Finally, the effect of Sm2O3NPs on various types of motility including swarming, swimming, and twitching was studied. Our results showed that Sm2O3NPs significantly inhibited biofilm formation of P. aeruginosa by 49-61%. Additionally, sub-MICs concentrations of Sm2O3NPs effectively decreased virulence factors including pyocyanin (33-55%), protease (24-45%), and hemolytic activity (22-41%). Moreover, swarming, swimming, and twitching motility remarkably was reduced after exposure to the NPs. The findings of this work showed that Sm2O3NPs have a high potential in inhibiting QS-dependent virulence of P. aeruginosa, which could be considered for antibacterial chemotherapy after further characterization.

Evaluation of the effect of ibuprofen in combination with ciprofloxacin on the virulence-associated traits, and efflux pump genes of Pseudomonas aeruginosa.

Biofilm formation and antibiotic efflux are two determinant factors in the development of drug resistance phenotype by Pseudomonas aeruginosa. Non-steroid anti-inflammatory drugs have shown the antimicrobial potential to be used in combination with antibiotics against bacterial pathogens. In this work, the effect of ibuprofen alone and in combination with ciprofloxacin on some virulence traits and the expression of the alginate synthesis and efflux pump genes of clinical isolates of P. aeruginosa was investigated. The checkerboard titration assay was used to evaluate the synergism of the drugs. P. aeruginosa strains were grown in the presence of sub-inhibitory concentrations of the drug and their biofilm formation level, swarming, swimming, and hemolytic activity were assessed. Also, the relative expression of the alg44, algT/U, mexB, and oprM genes was determined by qPCR assay. The MIC of ibuprofen and ciprofloxacin were measured 2048 and 32 µg/mL and the drugs showed synergic antibacterial activity (FIC = 0.4). Moreover, ibuprofen alone and in combination with ciprofloxacin, significantly reduced the expression of alg44 (0.22 and 0.25 folds) and algT/U (0.26 and 0.37 folds) genes, while increased the expression of the mexB (1.64 and 1.83 folds) and oprM (1.36 and 1.92 folds) genes. Simultaneous treatment of bacterial cells with ibuprofen and ciprofloxacin significantly decreased bacterial biofilm formation (65%), swimming, swarming, and hemolytic activity (85%), compared with the control. This work suggests that ibuprofen has considerable anti-virulence potential against P. aeruginosa and could be employed for combination therapy with antibiotics after further characterizations.

Ibuprofen involves with the reduced expression of pelD and pelF in pathogenic Pseudomonas aeruginosa strains.

Biofilm formation is an important factor in disease development by Pseudomonas aeruginosa. Similar to many bacterial species, biofilm formation in P. aeruginosa is regulated by the bacterial quorum sensing system. The pel genes are responsible for the synthesis of a glucose-rich polysaccharide that is associated with biofilm initiation and maturation. The antibiofilm potential of ibuprofen has been reported; however, the effect of the drug on the expression of the genes involved with biofilm formation has rarely been described. In this work, the effect of ibuprofen on the biofilm formation and expression of pelD and pelF genes among pathogenic P. aeruginosa strains was investigated. Multiple drug-resistant P. aeruginosa strains were treated with ibuprofen at ½ MIC concentration and their biofilm formation and expression of pelD and pelF genes was determined using the crystal violet and real-time PCR assays, respectively. The results showed that the ibuprofen at 1024 µg/mL significantly reduced biofilm formation of P. aeruginosa strains by 52-77%, compared with the controls. In addition, treating the bacteria with ibuprofen decreased the expression of pelD and pelF genes to 0.56 and 0.69 folds, respectively. We hypothesized that the attenuation of the pel genes could be associated with the reduction of bacterial QS autoinducers, which in turn reduced cellular c-di-GMP level. This work suggests that ibuprofen is a potent antibiofilm drug that could be used to enhance bacterial susceptibility to antimicrobials through the inhibition of biofilm formation.

Characterization of oxaliplatin removal by multispecies bacterial populations in moving bed biofilm and suspended-biomass reactors.

AIMS: This work aimed to characterize the oxaliplatin removal potential of multispecies microbial populations using the suspended-biomass (SB) and moving bed biofilm (MBB) reactors. METHODS AND RESULTS: Bacterial strains were isolated from pharmaceutical wastewater, their oxaliplatin degrading potential was screened and oxaliplatin removal efficacy in multispecies bacterial populations was investigated using HPLC. Five bacterial strains able to degrade oxaliplatin with an oxaliplatin removal efficacy of 21%-52% were isolated. The synthetic consortium including Xenorhabdus spp., Pantoea agglomerans and Bacillus licheniformis showed the highest potential with an oxaliplatin removal efficacy of 88.6% and 94.0% using the SB and MBB reactors, respectively. Also, the consortium reduced the chemical oxygen demand (COD) by 91.6 and 33% in MBB and SB reactors, respectively. A kinetic study showed a faster oxaliplatin removal in MBB (0.134 kg-1 ) than in the SB reactor (0.101 kg-1 ). Based on the GS/MS analysis, the overall biochemical pathway of oxaliplatin degradation was hypothesized to be initiated through the oxygenation of diamino-dicyclohexan-platinium complex and the cleavage of the aromatic ring. CONCLUSION: Microbial removal of oxaliplatin using MBB and SB reactors seems to be an efficient and promising approach for oxaliplatin removal in pharmaceutical and hospital wastewater treatment plants. SIGNIFICANCE AND IMPACT OF THE STUDY: Employing bacterial populations using the MBB reactor is a promising way to treat pharmaceutical wastewater to reduce the discharge of anticancer drugs into the environment.

Does ibuprofen affect the expression of alginate genes in pathogenic Pseudomonas aeruginosa strains?

Conversion to mucoid form is a crucial step in the pathogenesis of P. aeruginosa in burns and cystic fibrosis (CF) patients. Alginate is considered the major component of biofilm and is highly associated with the formation of mucoid biofilm in this species. Nonsteroid anti-inflammatory drugs (NSAIDs), including ibuprofen, have shown promising antibacterial and antibiofilm potential for bacterial pathogens. In this study, we aimed to evaluate the effect of ibuprofen on the expression of alginate synthetase (alg8), GDP-mannose dehydrogenase (algD), and alginate lyase (algL) genes in multiple drug-resistant (MDR) P. aeruginosa strains. The biofilm formation potential and the expression of alg8, algD, and algL among the bacteria treated with ibuprofen (at sub-inhibitory concentration) were investigated using the crystal violet staining and real-time PCR assays, respectively. The minimum inhibitory concentration of ibuprofen for the studied strains was determined 1024-2048 µg/mL. We observed that ibuprofen was able to reduce bacterial biofilm by 51-77%. Also, the expression of alg8, algD, and algL decreased by 32, 52, and 48%, respectively. The reduction of the genes responsible for alginate synthesis indicates promising antivirulece potential of ibuprofen to combat P. aeruginosa infection, especially in burns and CF patients. Our findings suggest that ibuprofen could be used to reduce the pathogenicity of P. aeruginosa that could be used in combination with antibiotics to treat drug-resistant infections.

Association of a genetic variant in Interleukin-10 gene with increased risk and inflammation associated with cervical cancer.

BACKGROUND: Cervical-cancer is among the most commonly diagnosed cancers in women, and infection with human papillomavirus (HPV) is associated with an increased risk of cervical cancer and altered serum concentrations of inflammatory cytokines. We have explored the association between a genetic variation in the Interleukin-10 (IL-10) gene (rs1800896) and cervical cancer risk and its relationship with tissue Interferon gamma (IFN-γ), Transforming growth factor beta (TGF-ß), Tumor necrosis factor alpha (TNF-α) concentrations in women with cervical cancer. METHODS: A total of 315 women with, or without cervical cancer, were recruited into the study. DNA was extracted from cervical cells, and genotyping was undertaken using Taq-man real-time PCR. The genotype frequency and allele distribution were analyzed together with their association with pathological data. The association of the rs1800896 gene variation with tissue levels of the inflammatory cytokines was also investigated. RESULTS: Our data showed a significant association between the A allele of the rs1800896 gene variant and the presence of cervical cancer. In particular, patients with AG/AA genotypes had an increased risk of cervical cancer with an odds ratio of 1.929 (95% confidence interval [CI]: 0.879-4.23, P < 0.001) in a recessive model, compared with the GG genotype. Also, the tissue concentrations of IFN-γ, TGF-ß, and TNF-α in cervical tissues were significantly higher in women with cervical cancer (P < 0.001) and were associated with the AA genotype. CONCLUSION: We have found an association between the polymorphism rs1800896 in the IL-10 gene and an increased risk of cervical cancer as well as a higher level of tissue inflammatory cytokines. Further investigations are necessary on the value of emerging biomarkers for the risk stratification for the management of cervical cancer patients.

Effects of heat shock protein inducer on Hsp70 gene expression and immune parameters during Streptococcus iniae infection in a Persian sturgeon fry.

Heat shock proteins (HSPs) as stress-related factors play a fundamental role in innate and adaptive immune responses in fish, which can be considered as strong candidates for the development of new methods for fish disease prevention. It has been proven that Pro-Tex® as a heat shock protein inducer (HSPi) reduces harmful effects of cellular stress by increasing the Hsp70 protein production. We evaluated the effects of Pro-Tex® as an HSPi in a Persian sturgeon, (Acipenser persicus) exposed to a pathogenic bacterium. Therefore, A. persicus fries were pre-treated with 25.00, 50.00 and 100 mg L-1 of Pro-Tex® and then, injected with Streptococcus iniae ATCC29178. The Hsp70 gene expressions were determined in various organs including liver, gill and intestine and lysozyme (LYZ) activities along with supplemental levels of complement component 3 (C3) and immunoglobulin M (IgM) were also determined in sturgeon blood in days 3 and 7 after infection. Expression of Hsp70 gene was increased during the first three days of infection and then, it was found to be down-regulated during the infection process. Also, levels of LYZ activity, C3 and IgM increased in a concentration-dependent manner; but these parameters decreased after 7 days. Our data suggest that induction of Hsp70 is a promising approach in modulation of immune response in A. persicus and it might be employed to confer protection in fish against bacterial infections.

Effect of curcumin on the expression of ahyI/R quorum sensing genes and some associated phenotypes in pathogenic Aeromonas hydrophila fish isolates.

Quorum sensing (QS) in Aeromonas hydrophila is mainly based on the modulation of ahyI/R genes that regulates bacterial virulence determinant phenotypes. The use of QS inhibitors would be of particular interest in inhibiting bacterial pathogenicity and infections. In this study, we aimed to determine the effect of curcumin, a natural component of Curcuma longa, on the expression of QS regulating genes, ahyI and ahyR, as well as some QS regulated virulence characteristics in pathogenic fish isolated A. hydrophila strains. The minimum inhibitory concentration (MIC) of curcumin against bacteria was determined using the broth micro-dilution method and the expression of quorum sensing genes ahyI and ahyR among the bacteria treated with curcumin was determined using quantitative polymerase chain reaction (qPCR). Also, the effect of curcumin on some QS associated traits, including biofilm formation, swarming and swimming motility, proteolytic potential, and bacterial hemolytic activity was investigated. According to the results, curcumin, at a concentration of 32 µg/mL, significantly reduced the expression of both ahyI and ahyR genes among bacterial strains up to 64.2 and 91.0%, respectively. Moreover, curcumin efficiently inhibited bacterial biofilm formation, swimming, and swarming motility. Also, bacterial proteolytic activity was slightly reduced, while hemolytic activity was not significantly affected. This study demonstrated the use of curcumin to attenuate ahyI/R QS genes and several QS associated phenotypes in A. hydrophila. These findings indicate the therapeutic potential of curcumin as an anti-QS agent, to be used against A. hydrophila pathogenesis in aquaculture.

Effect of silver nanoparticles conjugated to thiosemicarbazide on biofilm formation and expression of intercellular adhesion molecule genes, icaAD, in Staphylococcus aureus.

Biofilm formation is regarded as an important factor in the establishment of infections caused by Staphylococcus aureus. In the present study, phenotypic and molecular assays were used to evaluate antibiofilm potential of thiosemicarbazide (Tsc) conjugated with silver nanoparticles (Ag NPs) and functionalized by glutamic acid (Ag@Glu/Tsc NPs) against methicillin-resistant S. aureus (MRSA). Ag NPs were synthesized using precipitation method and conjugated to Tsc using glutamic acid. The NPs were characterized using SEM and FTIR spectroscopy analyses. Then, antibiofilm potential of the prepared NPs against MRSA strains was evaluated using phenotypic method and their effects on the expression of biofilm-associated genes icaA and icaD. Finally, the genes involved with the synthesis of intercellular adhesion molecules were determined. According to the results, Ag@Glu/Tsc NPs inhibited biofilm formation of MRSA strains up to 76.7% compared with the control. In addition, expression of the biofilm-associated genes icaA and icaD reduced by 66.7% and 60.3%, respectively in the presence of sub-inhibitory concentration of Ag@Glu/Tsc NPs. In conclusion, Ag@Glu/Tsc NPs could be considered as a potent antibacterial agent to inhibit bacterial biofilms.

Functionalization of ZnO Nanoparticles by Glutamic Acid and Conjugation with Thiosemicarbazide Alters Expression of Efflux Pump Genes in Multiple Drug-Resistant Staphylococcus aureus Strains.

Efflux-mediated drug resistance in bacterial strains is regarded as a major cause of drug resistance. In this study, we aimed to evaluate the expression of some major facilitator superfamily class efflux pump genes (EPGs) in the presence of ZnO nanoparticles (NPs) conjugated to thiosemicarbazide (TSC) under amine functionalization by glutamic acid (ZnO@Glu-TSC) as well as ciprofloxacin (CIP) among multiple drug-resistant Staphylococcus aureus. Synthesized NPs were characterized by ultraviolet-visible spectroscopy, X-ray diffraction pattern, and transmission electron microscopy. Antibiogram and ethidium bromide agar cartwheel method were used to determine the efflux-mediated multidrug-resistant phenotype of clinical strains. Then, expression of EPGs, including norA, norB, norC, and tet38 among the strains, exposed to ZnO@Glu-TSC and CIP was evaluated using quantitative real-time PCR (qPCR). According to the results, the strains resistant to CIP showed minimum inhibitory concentration (MIC) values ranging from 256 to 1,024 µg/mL, while ZnO@Glu-TSC NPs showed MICs from 8 to 256 µg/mL against bacterial strains, which indicates stronger antibacterial activity of NPs (2-8-fold) compared to CIP. ZnO@Glu-TSC NPs showed a good bacterial inhibitory potential with average inhibition zones of 11, 15, and 20 mm for concentrations of 50, 100, and 150 µg/mL, respectively. Moreover, simultaneous use of ZnO@Glu-TSC NPs (1/2 MIC) in combination with CIP (1/2 MIC) significantly reduced the expression of norA, norB, norC, and tet38 by 5.4-, 3.8-, 2.1-, and 3.4-fold, respectively, compared to the CIP alone. Therefore, ZnO@Glu-TSC NPs with their potent antimicrobial effects could be used as an antimicrobial agent against S. aureus for preventive and/or therapeutic approaches.

Isolation and molecular identification of a cellulotic bacterium from muncipal waste and investigation of its cellulase production / Isolamento e identificação molecular de uma bactéria celulolítica do lixo municipal e investigação de sua produção de celulase

Municipal waste is rich in lignocellulosic compounds which contain cellulose, lignin and hemicellulose. Microorganisms can break down such compounds and convert them into glucose and other carbohydrates. The current study was performed to isolate and identify cellulolytic bacteria in municipal waste. Municipal waste samples were collected and plated on Carboxymethyl cellulose (CMC) agar. Preliminary identification of the isolates was performed using standard biochemical assays. The activity of carboxymethyl cellulose (CMCase) was specified through measuring the release of reducing sugars from CMC. Different nitrogen sources at various concentrations and initial pH values were evaluated for their effect on enzyme production. Further the enzyme production was determined at different fermentation times. Molecular identification was then performed using bacterial 16s rRNA gene amplification and sequencing. A cellulolytic bacterium was isolated from municipal waste samples and identified based on morphological, physiological and biochemical characteristics along with 16S rRNA analysis. The isolated bacterium was identified as Bacillus subtilis (accession number: KU681044). Whose growth characteristics showed that its growth curve entered the logarithmic phase following 10­18 h with the stable growth phase ranging from 23 to 37 h. The optimal carbon source for fermentation was 1% rice hull, with the nitrogen source comprised of 2% peptone and yeast extract. The the minimum CMCase activity was observed at an initial medium pH of 4.0, while the maximum was observed at pH 7. The strain grew vigorously and the cellulase yield was high at 6­24 h fermentation time period. The isolated bacteria showed the degrading potential of cellulose which could be employed in local industrial process.

Resíduos urbanos são ricos em compostos lignocelulósicos que contêm celulose, lignina e hemicelulose. Microrganismos podem quebrar esses compostos e convertê-los em glicose e outros carboidratos. O presente estudo foi realizado para isolar e identificar bactérias celulolíticas em resíduos urbanos. Amostras de resíduos municipais foram coletadas e plaqueadas em ágar Carboximetilcelulose (CMC). A identificação preliminar dos isolados foi realizada utilizando ensaios bioquímicos padrão. A atividade da carboximetilcelulose (CMCase) foi especificada através da medição da liberação de açúcares redutores da CMC. Diferentes fontes de nitrogênio em várias concentrações e valores iniciais de pH foram avaliados quanto ao seu efeito na produção de enzimas. Além disso, a produção de enzima foi determinada em diferentes tempos de fermentação. A identificação molecular foi então realizada utilizando amplificação e sequenciamento do gene bacteriano 16s rRNA. Uma bactéria celulolítica foi isolada de amostras de resíduos urbanos e identificada com base em características morfológicas, fisiológicas e bioquímicas, juntamente com a análise 16S rRNA. A bactéria isolada foi identificada como Bacillus subtilis (número de acesso: KU681044). Cujas características de crescimento mostraram que sua curva de crescimento entrou na fase logarítmica após 10-18 h com a fase de crescimento estável variando de 23 a 37 h. A fonte de carbono ótima para a fermentação foi 1% de casca de arroz, com a fonte de nitrogênio composta de 2% de peptona e extrato de levedura. A atividade mínima de CMCase foi observada em um pH médio inicial de 4,0, enquanto a máxima foi observada em pH 7. A linhagem cresceu vigorosamente e o rendimento de celulase foi alto no período de 6 a 24 horas de fermentação. As bactérias isoladas mostraram o potencial de degradação da celulose que poderia ser empregada no processo industrial local.

Biofilm formation in uropathogenic Escherichia coli: association with adhesion factor genes

Background/aim: Biofilm formation is a major determinant factor in the development of urinary tract infections (UTIs) by uropathogenic Escherichia coli (UPEC). Several adhesion factors are involved in attachment of bacterial cells to the urinary tract and biofilm development. Materials and methods: The possible relationship between different adhesion factor genes (AFGs) and biofilm formation among UPEC isolates was investigated. Prevalence of different AFGs including fimA, fimH, papAH, papC, papEF, sfa-S, foc/G, and bmaE and their association to biofilm formation were investigated. Phenotypic expression of type 1 and P fimbriae was also investigated. Results: Our results showed that 84% of UPEC were moderate to strong biofilm producers. Prevalence of the type 1 and P fimbriae associated genes (fimA, fimH, papEF, papC) as well as the F1C fimbriae gene (foc/G) did not show a difference among different biofilm-producing groups, while higher prevalence of papAH, bmaE (M fimbriae), and sfaS (S-fimbriae) was observed for the strains producing moderate to strong biofilms. Phenotypic expression of type 1 fimbriae was associated with biofilm formation, while no association was observed for P fimbriae. Conclusion: Different AFGs (especially M and S fimbria) and their expression levels affect the biofilm formation ability of UPEC.

Two contrary roles of Fe3O4 nanoparticles on kinetic and thermodynamic of Paclitaxel degradation by Citrobacter amalonaticus Rashtia immobilized on sodium alginate gel beads.

Roles of Fe3O4 nanoparticles (NPs) on biodegradation of Paclitaxel by Citrobacter amalonaticus immobilized on alginate gel beads were investigated. Limitation in substrate diffusion is the major drawback of the cell immobilization method. To overcome this problem, bacterial cells were immobilized on the gel beads containing different concentrations (5-20mg/mL) of Fe3O4 NPs and their Paclitaxel degrading potential at different temperatures was investigated using kinetic and thermodynamic modeling. Co-immobilization of bacterial cells with 5, 10 and 20mg/mL Fe3O4 NPs enhanced biodegradation efficiencies to 66%, 80% and 78%, respectively, compared to the NPs free immobilized cells (41.9%). The optimum concentration of Fe3O4 NPs (10mg/mL) had both inhibitory and accelerating effects on paclitaxel degradation depending on the incubation time and temperature. Increasing dose of Fe3O4 NPs could increase paclitaxel degradation, despite increasing of thermodynamic inhibitory factors, only when longer time and higher temperature were used. ΔG values increased about 11.2 KJ/mol at all temperatures of 285, 295 and 305K, and ΔH increased 54.4%, in comparison with the treatment without NPs. This indicates that, inclusion of Fe3O4 NPs into the immobilization gels can increase the local concentration of Paclitaxel (with OH2+ groups) and bacterial accessibility to the substrate and thus enhance biodegradation efficiency.

Prevalence of ambler class a extended-spectrum- ß -lactamases (ESBLS) among Uropathogenic Escherichia coli strains isolated from Rasht city, Iran / Prevalência de ambler extended-spectrum classe A- ß -lactamases (ESBLs) entre Uropathogenic Escherichia coli isolados da cidade de Rasht, Irã

Extended spectrum -lactamases (ESBLs), a group of bacterial enzymes which are the major cause of resistance to penicillins, broad spectrum cephalosporins and monobactams, are found among the member of Enterobacteriaceae. The class A ESBLs are mainly encoded by the plasmid mediated blaSHV, blaTEM and blaCTX-M genes. In this study, prevalence of Ambler class A ESBL genes among uropathogenic E. coli (UPEC) isolates associated with community acquired infections and their antibiotic susceptibility pattern was investigated. Seventy UPEC strains were isolated from urine samples and subjected to antimicrobial susceptibility assay using disk diffusion method. Phenotypic screening of ESBL production was evaluated according to the CLSI combined disk method. Genotyping of Ambler class A ESBLs was investigated using PCR. According to the results, ESBLs was identified in 37 isolates while molecular assay showed 47 isolates harbored ESBL genes. The most prevalence was recorded for blaTEM (74.2%) followed by blaCTX-M (43.2%) and blaSHV (12.2%). Imipenem was the most effective drug and ESBL producing isolates showed higher resistance to CAZ, CRO, CFZ, CTX and FOX compared to non ESBL isolates. In conclusion, high prevalence of class A ESBL genes was observed in our study which needs more consideration and rational antibiotic prescription.

As -lactamases de espectro alargado (ESBLs), um grupo de enzimas bacterianas que são a principal causa de resistência às penicilinas, cefalosporinas de largo espectro e monobactamas, encontram-se entre os membros das Enterobacteriaceae. As ESBLs de classe A são principalmente codificadas pelos genes blaSHV, blaTEM e blaCTX-M mediados por plasmídeo. Neste estudo, foi investigada a prevalência dos genes ESBL de classe A de Ambler entre isolados de E. coli uropatogênicos (UPEC) e seu padrão de suscetibilidade aos antibióticos. Setenta cepas UPEC foram isoladas a partir de amostras de urina e submetidas a ensaio de susceptibilidade antimicrobiana utilizando o método de difusão em disco. O rastreio fenotípico da produção de ESBL foi avaliado de acordo com o método de disco combinado CLSI. A genotipagem de ESBL de classe A de Ambler foi investigada usando PCR. De acordo com os resultados, as ESBLs foram identificadas em 37 isolados enquanto que o ensaio molecular mostrou 47 isolados portadores de genes ESBL. A maior prevalência foi registrada para blaTEM (74,2%), seguida de blaCTX-M (43,2%) e blaSHV (12,2%). O imipenem foi o fármaco mais eficaz e os isolados produtores de ESBL apresentaram maior resistência a CAZ, CRO, CFZ, CTX e FOX em comparação com os isolados não ESBL. Em conclusão, a alta prevalência de genes ESBL de classe A foi observada em nosso estudo, que necessita de maior atenção e prescrição de antibióticos racionais.

Microbial degradation of Paclitaxel using Citrobacter amalonaticus Rashtia isolated from pharmaceutical wastewater: kinetic and thermodynamic study.

Paclitaxel is a highly toxic anticancer agent which is used in a wide range against ovarian, breast, lung, and prostate cancers. Paclitaxel is manufactured recently in the north of Iran which may lead to the introduction of the drug into the environment via pharmaceutical wastewater. To our knowledge, Paclitaxel degradation is currently performed using physicochemical methods and biological degradation of Paclitaxel has not been reported. In this study, a Paclitaxel degrading bacterium was isolated from pharmaceutical wastewater for the first time. The bacterium was identified using biochemical and molecular assays and its Paclitaxel degradation potential was evaluated using High Performance Liquid Chromatography (HPLC). In addition, kinetic and thermodynamic study of Paclitaxel degradation at different experimental conditions was performed. A Citrobacter species named as C. amalonaticus Rashtia able to degrade and utilize Paclitaxel as the sole carbon source was isolated. The isolated strain tolerated high level concentration of Paclitaxel (0.4 mg/mL) in liquid culture media and was able to degrade spillage-level concentrations of the drug (0.01-0.1 mg/mL) with 87-93 % efficacy under aerobic condition. Kinetic and thermodynamic study at different pHs (4.0, 7.0 and 10.0) and temperatures (285, 295 and 310 K) revealed that Paclitaxel degradation is a non-spontaneous process and the highest rate constant was observed in the basic condition and at the highest temperature. The ΔG values at 285, 295 and 310 K were determined 103.3, 105.9 and 109.9 kJ/mol, respectively. In addition, The ΔH and activation energy (Ea) of the process were determined +28.7 kJ/mol and +30.87 kJ/mol, respectively.