Occurrence, genetic diversity and antibiotic resistance of Arcobacter sp. in a dairy plant.

AIMS: The aim of this study was to evaluate the occurrence, diversity and resistance to antibiotics of Arcobacter sp. in a dairy plant samples. METHODS AND RESULTS: A total of 75 samples from dairy plant surfaces and materials and several food products collected in different steps of the cheese production process were analysed by culture, under aerobic and microaerobic atmospheric conditions, and by enrichment molecular detection. Isolates were identified and genotyped by ERIC-PCR, and their susceptibility to nine antibiotics was evaluated by agar dilution. Global prevalence of Arcobacter sp. was 42·7%, where 20 of the 42 food samples analysed were positive for A. butzleri by both culture and molecular detection, one for A. marinus by culture and one for A. cryaerophilus by molecular detection only; 10 of the 30 analysed materials and plant surfaces were positive for A. butzleri. All A. butzleri isolates were resistant to nalidixic acid and showed high resistance rates to ampicillin (56·2%) and cefotaxime (97·9%), being all strains susceptible to gentamicin and erythromycin. CONCLUSIONS: Contamination of dairy plant environment with A. butzleri and its progression along cheese production process were observed, however, the cheese ripening process may have a relevant role in the reduction of the contamination. SIGNIFICANCE AND IMPACT OF THE STUDY: This study showed the presence of Arcobacter sp. in a dairy plant, displaying its high prevalence and genetic diversity and highlighting its high resistance rates. The data obtained could contribute to further acknowledge the Arcobacter food contamination as a potential health hazard.

Synergistic activity of coriander oil and conventional antibiotics against Acinetobacter baumannii.

In this study we investigated the existence of synergistic antibacterial effect between coriander (Coriandrum sativum L.) essential oil and six different antibacterial drugs (cefoperazone, chloramphenicol, ciprofloxacin, gentamicin, tetracycline and piperacillin). The antibacterial activity of coriander oil was assessed using microdilution susceptibility testing and synergistic interaction by checkerboard assays. The association of coriander essential oil with chloramphenicol, ciprofloxacin, gentamicin and tetracycline against Acinetobacter baumannii showed in vitro effectiveness, which is an indicator of a possible synergistic interaction against two reference strains of A. baumannii (LMG 1025 and LMG 1041) (FIC index from 0.047 to 0.375). However, when tested the involvement between coriander essential oil and piperacillin or cefoperazone, the isobolograms and FIC index showed an additive interaction. The in vitro interaction could improve the antimicrobial effectiveness of ciprofloxacin, gentamicin and tetracycline and may contribute to resensitize A. baumannii to the action of chloramphenicol.

Screening of antimicrobial activity of Cistus ladanifer and Arbutus unedo extracts.

In this work, the in vitro antimicrobial activity of different crude extracts obtained from Cistus ladanifer L. and Arbutus unedo L. was investigated. The ethanol, methanol and acetone/water extracts of Cistus ladanifer and Arbutus unedo were prepared using different extraction methods and their antimicrobial activities against reference strains, including three Gram-positive, five Gram-negative and three yeasts, and against clinical isolates of Helicobacter pylori and methicillin-resistant Staphylococcus aureus, were investigated. All the extracts inhibited more than one microorganism; moreover all of them presented antimicrobial activity against the Gram-positive bacteria, Klebsiella pneumonia, Candida tropicalis and Helicobacter pylori. It is noteworthy that the most considerable in vitro effect was observed against Helicobacter pylori. These inhibitory effects can be considered relevant to the development of new agents for inclusion in the treatment or prevention of infections by the tested strains.

An evaluation of the potential of Acacia dealbata as raw material for bioethanol production.

In this work, the potential of Acacia dealbata as raw material for ethanol production was evaluated, as well as its composition with regard to cellulose, hemicelluloses, lignin, extractives and ash. The tree samples were subjected to several dilute acid pretreatments using a combined severity parameter ranging from 0.7 to 3.7. The highest ethanol concentration obtained was 10.31 g ethanol/L within 24 h by using a separate hydrolysis and fermentation of the water insoluble fraction after pretreatment at 180 °C with 0.8% of sulfuric acid for 15 min. With simultaneous saccharification and fermentation, results obtained for the washed solids of water insoluble fraction were better than those obtained with the whole slurry.

Bioethanol from the Portuguese forest residue Pterospartum tridentatum--an evaluation of pretreatment strategy for enzymatic saccharification and sugars fermentation.

Under the current energy scenario, the development of alternatives to fossil fuels, like bioethanol from lignocellulosic materials, is highly relevant. Therefore it is important to search and study new raw materials and to optimize the different steps that lead to bioethanol production. In this work, acid diluted pretreatment was optimized considering the release of sugars. Under the optimal conditions, the reducing sugars yield was of 293.4mg/g of dry biomass in liquid fraction. The tested pretreated samples of Pterospartum tridentatum that presented a higher glucose yield in enzymatic saccharification where those that were subject to a pretreatment at 180°C for 75min with 2.75% (w/w) of sulfuric acid when using a biomass/liquid ratio of 2.25g/10mL leading to a maximum yield of glucose that was 92% of the theoretical maximum. From the fermentation of filtrates it was possible to obtain a maximum ethanol yield of 0.26g ethanol/g total sugars, without previous detoxification.

Comparison of relative renal function measured with either 99mTc-DTPA or 99mTc-EC dynamic scintigraphies with that measured with 99mTc-DMSA static scintigraphy.

OBJECTIVE: The aim of this study was to compare the renal function measured with either 99mTc-DTPA or 99mTc-EC dynamic scintigraphies with that measured using 99mTc-DMSA static scintigraphy. METHODS: the values of relative renal function measured in 111 renal dynamic scintigraphies performed either with 99mTc-DTPA (55 studies) or with 99mTc-EC (56 studies) were compared with the relative function measured using 99mTc-DMSA static scintigraphy performed within a 1-month period. The comparisons were performed using Wilcoxon signed rank test. The number of 99mTc-DTPA and 99mTc-EC studies that presented relative renal function different by more than 5% from that measured with 99mTc-DMSA, using chi square test were also compared. RESULTS: the relative renal function measured with 99mTc-EC is not statistically different from that measured with 99mTc-DMSA (p = 0.97). The relative renal function measured with 99mTc-DTPA was statistically different from that measured using 99mTc-DMSA, but with a borderline statistical significance (p = 0.05). The number of studies with relative renal function different by more than 5% from that measured with 99mTc-DMSA is higher for the 99mTc-DTPA scintigraphy (p = 0.04) than for 99mTc-EC. CONCLUSION: the relative renal function measured with 99mTc-EC dynamic scintigraphy is comparable with that measured with 99mTc-DMSA static scintigraphy, while the relative renal function measured with 99mTc-DTPA dynamic scintigraphy presents a significant statistical difference from that measured with 99mTc-DMSA static scintigraphy.

Comparison of relative renal function measured with either 99mTc-DTPA or 99mTc-EC dynamic scintigraphies with that measured with 99mTc-DMSA static scintigraphy

OBJECTIVE: The aim of this study was to compare the renal function measured with either 99mTc-DTPA or 99mTc-EC dynamic scintigraphies with that measured using 99mTc-DMSA static scintigraphy. METHODS: the values of relative renal function measured in 111 renal dynamic scintigraphies performed either with 99mTc-DTPA (55 studies) or with 99mTc-EC (56 studies) were compared with the relative function measured using 99mTc-DMSA static scintigraphy performed within a 1-month period. The comparisons were performed using Wilcoxon signed rank test. The number of 99mTc-DTPA and 99mTc-EC studies that presented relative renal function different by more than 5 percent from that measured with 99mTc-DMSA, using chi square test were also compared. RESULTS: the relative renal function measured with 99mTc-EC is not statistically different from that measured with 99mTc-DMSA (p = 0.97). The relative renal function measured with 99mTc-DTPA was statistically different from that measured using 99mTc-DMSA, but with a borderline statistical significance (p = 0.05). The number of studies with relative renal function different by more than 5 percent from that measured with 99mTc-DMSA is higher for the 99mTc-DTPA scintigraphy (p = 0.04) than for 99mTc-EC. CONCLUSION: the relative renal function measured with 99mTc-EC dynamic scintigraphy is comparable with that measured with 99mTc-DMSA static scintigraphy, while the relative renal function measured with 99mTc-DTPA dynamic scintigraphy presents a significant statistical difference from that measured with 99mTc-DMSA static scintigraphy.

Isolation of a fusion protein containing the antigenic domain 1 of human cytomegalovirus glycoprotein B and its application in ELISA tests.

The glycoprotein B (gB) of human cytomegalovirus represents a dominant antigen for the humoral immune response. The immunodominant region on gB is the antigenic domain 1 (AD-1), a complex structure that requires a minimal continuous sequence of more than 75 amino acids for antibody binding. In this study, this domain was expressed in Escherichia coli as a fusion protein with beta-galactosidase but yielded insoluble protein aggregates as inclusion bodies. To recover the fusion protein, inclusion bodies were solubilized by two extractions with urea 8 M: and the fusion protein then isolated using gel filtration chromatography. After confirmation of fusion protein antigenicity by Western blotting, the purified product was used as the capturing antigen in an enzyme-linked immunosorbent assay (ELISA) to determine the presence of viral antibodies in serum samples of pregnant women. A cut-off point of approximately 0.2 absorbance units could discriminate the results of seropositive from seronegative pregnant women. The data indicates the potential usefulness of the fusion protein for the development of immunoassay for detection of the HCMV antibodies.

Improved recovery of a fusion protein containing the antigenic domain 1 of the human cytomegalovirus glycoprotein B.

Heterologous expression in Escherichia coli often leads to production of the expressed proteins as insoluble and inactive inclusion bodies. The general strategy for protein recovery includes isolation and washing of inclusion bodies, solubilization of aggregated protein and refolding of solubilized protein. The process of refolding, as well as the other steps involved in inclusion body recovery, must be optimized according to the characteristics of each protein. For the development of reliable and inexpensive serodiagnostic tests, the antigenic domain 1 (AD-1) of human cytomegalovirus glycoprotein B was expressed in E. coli and a process was developed to increase recovery of the fusion protein containing AD-1. A comparison of disruption methods and different conditions involved in recovery of this fusion protein from inclusion bodies is presented. The developed method gives a high yield of the fusion protein with a purity sufficient for use in diagnostic tests.