Biomedical subjects

J Vila

Publications and source records attributed to J Vila.

At least 19 recordsLinked to original sources

PubMed2007

Biofilm formation in uropathogenic Escherichia coli strains: relationship with prostatitis, urovirulence factors and antimicrobial resistance.

PURPOSE: Escherichia coli strains are the most frequent cause of urinary tract infections. Biofilm formation allows the strains to persist a long time in the genitourinary tract and interfere with bacterial eradication. We determined the possible relationships between the different urinary tract infections, and in vitro biofilm formation, the presence of urovirulence factors and nalidixic acid resistance. MATERIALS AND METHODS: A total of 151 E. coli strains collected from patients with cystitis (44 strains), pyelonephritis (75) and prostatitis (32) were analyzed for in vitro biofilm formation, the phylogenetic group, the presence of several urovirulence factors and resistance to nalidixic acid. RESULTS: E. coli strains causing prostatitis produced biofilm in vitro more frequently than those causing other urinary tract infections and had a higher frequency of hemolysin (p = 0.03 and 0.0002, respectively). However, only hemolysin was independently associated with prostatitis. On the other hand, strains forming biofilm presented a significantly higher frequency of hemolysin and type 1 fimbriae expression. CONCLUSIONS: Although hemolysin is the main virulence factor by which E. coli causes acute prostatitis, the association between hemolysin and biofilm formation may result in increased ability of E. coli strains to persist in the prostate.

Biofilms↗

PubMed2006

Antibacterial evaluation of a collection of norfloxacin and ciprofloxacin derivatives against multiresistant bacteria.

The objective of this study was to analyse an array of ciprofloxacin and norfloxacin derivatives in order to determine those with good activity against bacteria that already present fluoroquinolone resistance associated with mutations in the gyrA and/or parC genes. Four norfloxacin and 20 ciprofloxacin derivatives were synthesised and tested against quinolone-susceptible and -resistant Escherichia coli, Acinetobacter baumannii, Stenotrophomonas maltophilia and Staphylococcus aureus strains using a microdilution test. Among the derivatives, the 4-methyl-7-piperazine ciprofloxacin derivative showed a minimum inhibitory concentration for 50% of the organisms that was 16- and 8-fold lower than ciprofloxacin for A. baumannii and S. maltophilia, respectively. When the methyl group at position 4 in the piperazine ring was substituted by ethyl, butyl or heptyl groups, activity against A. baumannii steadily decreased. The 7-(4-methyl)-piperazine ciprofloxacin derivative (UB-8902) showed very good activity against these multiresistant microorganisms including A. baumannii and S. maltophilia.

Anti-Bacterial Agents↗

PubMed2006

Trials of bioremediation on a beach affected by the heavy oil spill of the Prestige.

The objective of this study was to assess the efficiency of several bioremediation products in accelerating the in situ biodegradation of the heavy fuel oil spill of the Prestige. Trials of bioremediation were conducted in sand, rocks and granite tiles on the beach of Sorrizo (A Coruña, NW Spain) that was polluted by the spill. Neither the added microorganisms nor the nutrients significantly enhanced the degradation rate of the fuel oil in rocks, granite tiles or sand. PAH degradation up to 80% was determined in sand and tiles. In tiles the oxygen content of the residual oil increased from 1.6% up to 8% in 90 days, which could be explained by the accumulation of products coming from the partial oxidation of the hydrocarbons. Eighteen months after the spill, the rocks of the beach were still coated by a black layer of weathered fuel oil. For this reason an oleophilic product, sunflower biodiesel was tested on a rock. The application of biodiesel accelerated the gradually clean-up of the polluted surface and could also accelerate the degradation of the residual oil.

Biodegradation, Environmental↗

PubMed2006

Dietary patterns and associated lifestyles in preconception, pregnancy and postpartum.

OBJECTIVE: To identify dietary patterns in women who are planning immediate pregnancy in preconception, weeks 6, 10, 26 and 38 of pregnancy, and 6 months postpartum, and to describe how particular lifestyles, the body mass index (BMI) and sociodemographic factors are associated to these patterns. DESIGN: Longitudinal study throughout the reproductive cycle of food consumption carried out in a Spanish Mediterranean city. SETTING: Faculty of Medicine and Health Sciences, Rovira i Virgili University. SUBJECTS: In total, 80 healthy female volunteers who were planning immediate pregnancy. INTERVENTIONS: A seven-consecutive-day dietary record was used to evaluate the dietary intake. Exploratory factor analysis was used to identify the main dietary patterns in each of the periods. Fitted multiple linear regression models were used to study the associations between the lifestyle and sociodemographic variables, and each dietary pattern. RESULTS: The 'sweetened beverages and sugars' pattern was identified from preconception to 6 months postpartum and the 'vegetables and meat' pattern to the end of pregnancy. The 'sweetened beverages and sugars' pattern is positively associated with smoking and negatively associated with physical activity before conception and in the first trimester of pregnancy. The 'vegetables and meat' pattern is negatively associated with the BMI during the preconception period and positively associated with age in weeks 10 and 38 of pregnancy. It is shown that the patterns do not change significantly throughout the period studied. CONCLUSIONS: We have identified two stable dietary patterns from preconception to postpartum. The 'sweetened beverages and sugars' pattern is associated with habits of risk for the health of the pregnant woman and her offspring. SPONSORSHIP: 'Comisión Interministerial de Ciencia y Tecnología' (CICYT: ALI89-0388) and 'Instituto de Salud Carlos III', RCMN (C03/08), Madrid, Spain'.

Adolescent↗

PubMed2006

Implication of biofilm formation in the persistence of urinary tract infection caused by uropathogenic Escherichia coli.

Escherichia coli is the most frequent microorganism involved in urinary tract infection (UTI). Acute UTI caused by uropathogenic E. coli (UPEC) can lead to recurrent infection, which can be defined as either re-infection or relapse. E. coli strains causing relapse (n = 27) and re-infection (n = 53) were analysed. In-vitro production of biofilm, yersiniabactin and aerobactin was significantly more frequent among strains causing relapse. Biofilm assays may be helpful in selecting patients who require a therapeutic approach to eradicate persistent biofilm-forming E. coli strains and prevent subsequent relapses.

Adult↗

PubMed2006

Quinolones induce partial or total loss of pathogenicity islands in uropathogenic Escherichia coli by SOS-dependent or -independent pathways, respectively.

Escherichia coli is the most common microorganism causing urinary tract infections. Quinolone-resistant E. coli strains have fewer virulence factors than quinolone-susceptible strains. Several urovirulence genes are located in pathogenicity islands (PAIs). We investigated the capacity of quinolones to induce loss of virulence factors such as hemolysin, cytotoxic necrotizing factor 1, P fimbriae, and autotransporter Sat included in PAIs in three uropathogenic E. coli strains. In a multistep selection, all strains lost hemolytic capacity at between 1 and 4 passages when they were incubated with subinhibitory concentrations of ciprofloxacin, showing a partial or total loss of the PAI containing the hly (hemolysin) and cnf-1 (cytotoxic necrotizing factor 1) genes. RecA(-) mutants were obtained from the two E. coli strains with partial or total loss of the PAI. The inactivation of the RecA protein affected only the partial loss of the PAI induced by quinolones. No spontaneous loss of PAIs was observed on incubation in the absence of quinolones in either the wild-type or mutant E. coli strains. Quinolones induce partial or total loss of PAIs in vitro in uropathogenic E. coli by SOS-dependent or -independent pathways, respectively.

Anti-Infective Agents↗

PubMed2006

[Prevalence of the tetA and tetB genes as mechanisms of resistance to tetracycline and minocycline in Acinetobacter baumannii clinical isolates].

INTRODUCTION: Two hundred twenty-one Acinetobacter baumannii clinical strains were collected from 25 hospitals in Spain. The aim of this study was to analyze the prevalence of the tetA and tetB genes in a collection of A. baumannii strains that were not epidemiologically related. METHODS: The strains were distributed in 79 clones by genomic DNA analysis with low frequency restriction enzymes and pulsed-field gel electrophoresis. The MICs for tetracycline and minocycline were determined by the E-test. One strain representing each of the tetracycline-resistant clones was analyzed by polymerase chain reaction (PCR) with specific primers for the tetA and tetB genes. RESULTS: Fifty-nine (74.7%) out of the 79 clones were tetracycline-resistant (MIC > or = 16 mg/l) and 40 (50.6% of the total) were also minocycline-resistant (MIC > 1 mg/l). One strain representative of each tetracycline-resistant clone was taken to study the prevalence of the tetA and tetB genes. The PCR analysis showed that 39 strains representing the same number of clones (66%) had the tetB gene, while only 8 (13.6%) were positive for the tetA gene. Twelve strains did not have any of these genes. None of the analyzed strains had both genes. CONCLUSION: Although resistance to tetracycline in Acinetobacter baumannii clinical isolates is greater than that to minocycline, the tetB gene, which affects both antimicrobial agents, has a higher prevalence than the tetA gene, which affects only tetracycline.

Acinetobacter baumannii↗

PubMed2005

Electrical conductivity of aqueous solutions of aluminum salts.

We present experimental measurements of the specific electrical conductivity (sigma) in aqueous solutions of aluminum salts at different temperatures, covering all salt concentrations from saturation to infinite dilution. The salts employed were AlCl(3), AlBr(3), AlI(3), and Al(NO(3))(3), which present a 1:3 relationship between the electrical charges of anion and cation. In addition, we have measured the density in all ranges of concentrations of the four aqueous electrolyte solutions at 298.15 K. The measured densities show an almost linear behavior with concentration, and we have fitted it to a second order polynomial with very high degree of approximation. The measurement of the specific conductivity at constant temperature reveals the existence of maxima in the conductivity vs concentration curves at molar concentrations around 1.5M for the three halide solutions studied, and at approximately 2M for the nitrate. We present a theoretical foundation for the existence of these maxima, based on the classical Debye-Hu ckel-Onsager hydrodynamic mean-field framework for electrical transport and its high concentration extensions, and also a brief consideration of ionic frictional coefficients using mode-coupling theory. We also found that the calculated values of the equivalent conductance vary in an approximately linear way with the square root of the concentration at concentrations as high as those where the maximum of sigma appears. Finally, and for completeness, we have measured the temperature dependence of the electrical conductivity at selected concentrations from 283 to 353 K, and performed a fit to an exponential equation of the Vogel-Fulcher-Tamman type. The values of the calculated temperatures of null mobility of the four salts are reported.

Journal Article↗

PubMed2005

Genetic diversity of Shigella species from different intercontinental sources.

One hundred and twenty three strains of Shigella spp. (mostly Shigella sonnei and Shigella flexneri) were isolated between 1995 and 2000 from patients suffering from traveller's diarrhoea. Seventy nine of them have been typed by digestion of their chromosomal DNA with Xba I and pulsed field gel electrophoresis. Results show a high degree of heterogeneity in both S. sonnei and S. flexneri isolates. This is the first time that the molecular typing of such a high number of geographically unrelated isolates of Shigella sp. is carried out, showing a high level of genomic re-arrangement.

Bacterial Typing Techniques↗

PubMed2005

Antioxidant effect of virgin olive oil in patients with stable coronary heart disease: a randomized, crossover, controlled, clinical trial.

The Mediterranean diet, in which olive oil is the main source of fat, has been associated with a reduced incidence of coronary heart disease (CHD) and low blood pressure levels. Virgin olive oil (VOO), besides containing monounsaturated fat, is rich in phenolic compounds (PC) with antioxidant properties. The aim of this study was to examine the antioxidant and anti-hypertensive effect of two similar olive oils, but with differences in their PC (refined: 14.7 mg/kg versus virgin: 161.0 mg/kg), in 40 males with stable CHD. The study was a placebo controlled, crossover, randomized trial. A raw daily dose of 50 mL of VOO and refined olive oil (ROO) were sequentially administered over two periods of 3 weeks, preceded by 2-week washout periods in which ROO was used. Lower plasma oxidized LDL (p < 0.001) and lipid peroxide levels (p = 0.003), together with higher activities of glutathione peroxidase (p = 0.033), were observed after VOO intervention. Systolic blood pressure decreased after intake of VOO (p = 0.001) in hypertensive patients. No changes were observed in diastolic blood pressure, glucose, lipids, and antibodies against oxidized LDL. Consumption of VOO, rich in PC, could provide beneficial effects in CHD patients as an additional and complementary intervention to the pharmacological treatment.

Aged↗

PubMed2005

[Lung cancer at a university hospital: epidemiological and histological characteristics of a recent and a historical series].

OBJECTIVE: To describe the clinical, histological, and epidemiological characteristics of patients diagnosed with lung cancer in our hospital over a period of 5 years and compare them with those of historical cases treated at the same hospital. PATIENTS AND METHODS: The cases of patients diagnosed with lung cancer from January 1998 through December 2002 were studied retrospectively and compared with data published for the period from 1978 through March 1981. RESULTS: A total of 678 patients (89% men, mean age 67 years) were studied. Fifty-six percent of the men and 38% of the women were smokers (P<.001). The most common histological types were squamous cell carcinoma (33%) and adenocarcinoma (30%): squamous carcinoma in men (36%) and adenocarcinoma in women (56%). Metastasis was present in 42% of the patients with non-small cell lung cancer and in 55% of those with small cell lung cancer. In patients with a history of neoplastic disease, laryngeal tumors were most common in patients with squamous carcinoma whereas bladder tumors were the most frequent in patients with adenocarcinoma. The ratio of men to women was lower in the recent series than in the historical one. The percentage of squamous carcinoma was lower and that of adenocarcinoma higher (P<.001). The percentage of patients diagnosed with regional involvement was greater in the recent series (P<.001). CONCLUSIONS: Squamous cell carcinoma continues to be the most frequent histological type. Male sex and smoking are associated with squamous carcinoma and female sex is associated with adenocarcinoma. Epidemiological and histological patterns have changed, possibly in relation to changes in smoking habits.

Adenocarcinoma↗

PubMed2005

[Validation of a respiratory polygraphy system in the diagnosis of sleep apnea syndrome].

OBJECTIVE: To validate a cardiorespiratory polygraphy system (BITMED NGP 140) by comparing it to conventional polysomnography in the diagnosis of sleep apnea-hypopnea syndrome. PATIENTS AND METHODS: Polysomnography and cardio-respiratory polygraphy were performed simultaneously on 103 consecutive patients referred because of suspected sleep apnea-hypopnea syndrome. The Bland and Altman method and intraclass correlation coefficients were used to assess agreement between the 2 methods of measurement. Receiver operating characteristic (ROC) curves were used to calculate the yield of cardiorespiratory polygraphy compared to that of conventional polysomnography. RESULTS: Ninety-two valid studies were obtained for 72 men and 20 women (mean [SD] age: 52.4 [12] years). By the Bland and Altman method, the difference between the respiratory event index obtained with the BITMED NGP140 and the apnea-hypopnea index (AHI) obtained by conventional polysomnography was 7.6 (13.2) in the manual analysis (95% confidence interval [CI], 4.9-10.4) and 12 (15.3) (95% CI, 8.8-15.3) in the automatic analysis. For a corrected AHI (AH/total time in bed) mean differences were -2.2 (5.9) and 2.4 (8.2) for manual and automatic analysis. The intraclass correlation coefficients were greater than 0.94. The areas under the ROC curves of the respiratory event index were greater than 0.97 for all cut points. For an AHI of 30 or higher, the best cut-off point determined by manual cardiorespiratory polygraphy analysis was 27 (sensitivity, 98% and specificity, 98%). For the different cut-off points cardiorespiratory polygraphy correctly classified between 92% and 98% of patients in both the manual and automatic analyses. CONCLUSIONS: The BITMED NGP140 had good agreement with conventional polysomnography for the measurement of respiratory events and provided high diagnostic yield.

Adult↗

PubMed2005

Isolation of an amikacin-resistant Escherichia coli strain after tobramycin treatment of previous recurrent episodes of respiratory tract infections caused by Pseudomonas aeruginosa.

Amikacin-resistant Escherichia coli strains are isolated rarely from clinical samples. In the present study, investigation of an amikacin-resistant clinical isolate of E. coli demonstrated the presence of two class 1 integrons carrying the aacA4 gene plus the aacA7 gene, and the dfrA17 gene plus the aadA5 gene, respectively. Resistance to amikacin in this E. coli isolate was related to the presence of both aacA4 and aacA7.

Amikacin↗

PubMed2005

The selection of resistance to and the mutagenicity of different fluoroquinolones in Staphylococcus aureus and Streptococcus pneumoniae.

Two quinolone-susceptible Staphylococcus aureus and five quinolone-susceptible Streptococcus pneumoniae isolates were used to obtain in-vitro quinolone-resistant mutants in a multistep resistance selection process. The fluoroquinolones used were ciprofloxacin, moxifloxacin, levofloxacin, gemifloxacin, trovafloxacin and clinafloxacin. The mutagenicity of these quinolones was determined by the Salmonella and the Escherichia coli retromutation assays. All quinolone-resistant Staph. aureus mutants had at least one mutation in the grlA gene, while 86.6% of quinolone-resistant Strep. pneumoniae mutants had mutations in either or both the gyrA and parC genes. Moxifloxacin and levofloxacin selected resistant mutants later than the other quinolones, but this difference was more obvious in Staph. aureus. Accumulation of the fluoroquinolones by Staph. aureus did not explain these differences, since levofloxacin and moxifloxacin accumulated inside bacteria to the same extent as clinafloxacin and trovafloxacin. The results also showed that moxifloxacin and levofloxacin had less mutagenic potency in both mutagenicity assays, suggesting a possible relationship between the selection of resistance to quinolones and the mutagenic potency of the molecule. Furthermore, gemifloxacin selected efflux mutants more frequently than the other quinolones used. Thus, the risk of developing quinolone resistance may depend on the density of the microorganism at the infection site and the concentration of the fluoroquinolone, and also on the mutagenicity of the quinolone used, with moxifloxacin and levofloxacin being the least mutagenic.

Aza Compounds↗

PubMed2005

Risk-factors for the acquisition of imipenem-resistant Acinetobacter baumannii in Spain: a nationwide study.

Potential risk-factors for the acquisition of imipenem-resistant Acinetobacter baumannii were investigated in a cohort study in 25 Spanish hospitals. The clonal relationship among isolates was determined by pulsed-field gel electrophoresis (PFGE). In total, A. baumannii was isolated from 203 patients, with imipenem-resistant (MIC(90) 128 mg/L) isolates being obtained from 88 patients (43%), and imipenem-susceptible isolates from 115 patients (57%). A wide clonal distribution was observed among the imipenem-resistant isolates, but spread of the same clone among centres was not demonstrated. The results indicated that imipenem-resistant A. baumannii is a widely distributed nosocomial pathogen in Spain and reaches an alarming frequency in some centres. Independent risk-factors for the acquisition of imipenem-resistant A. baumannii were a hospital size of >500 beds (multivariate OR, 6.5; 95% CI, 1.8--23), previous antimicrobial treatment (multivariate OR, 4.3; 95% CI, 1.6--11), a urinary catheter (multivariate OR, 2.7; 95% CI, 1.1--6.7) and surgery (multivariate OR, 2; 95% CI, 1.07--3.8).

Acinetobacter Infections↗

PubMed2005

Analysis of the mechanisms of resistance to several antimicrobial agents in Shigella spp. causing travellers' diarrhoea.

Eighty isolates of Shigella spp. (37 Shigella flexneri and 43 Shigella sonnei) from patients with travellers' diarrhoea were studied. Susceptibility tests revealed high levels of resistance, especially to ampicillin (65%), tetracycline (78%) and trimethoprim (75%), and particularly among the S. flexneri isolates. Dihydrofolate reductase 1 genes (dfrA1) were prevalent among the trimethoprim-resistant isolates, while oxa genes predominated among the ampicillin-resistant isolates. Chloramphenicol resistance was associated with production of chloramphenicol acetyltransferase, while nalidixic acid-resistant isolates had a single mutation in the gyrA gene. The results indicate a continuing need for resistance surveillance and rational use of antimicrobial agents.

Ampicillin↗

PubMed2005

Chondroitin sulfate and hyaluronic acid (500-730 kda) inhibit stromelysin-1 synthesis in human osteoarthritic chondrocytes.

Chondroitin sulfate (CS) and 500-730 kDa hyaluronic acid (HA) are symptomatic slow-acting drugs for the treatment of osteoarthritis (OA). In addition, a growing body of evidence suggests a role for CS and this specific HA as modifiers of the course of OA. The therapeutic efficacy of CS and HA lies in their different mechanisms of action. Stromelysin-1 (metalloprotease-3 [MMP-3]) is a cartilage proteolytic enzyme, which induces cartilage destruction and acts as a mediator of the inflammatory response. However, there are few studies evaluating the in vitro effect of CS and HA on MMP-3 synthesis in human chondrocyte cultures from OA patients. Thus, the aim of the present study was to analyze the effect of CS and HA (500-730 kDa) on MMP-3 synthesis induced by interleukin-1beta (IL-1beta) in chondrocytes from patients with hip OA. Chondrocyte cultures were incubated for 48 h with IL-1beta (2.5 ng/ml) in the absence or presence of different HA 500-730 kDa (Hyalgan, Bioibérica Farma, Barcelona, Spain) concentrations, or alternatively, CS (Condro.san, Bioibérica Farma) at concentrations of 10, 50, 100, 150, 200 and 1,000 microg/ml. The results revealed that both CS and HA (500-730 kDa) inhibited MMP-3 synthesis induced by IL-1beta in human OA chondrocytes. Specifically, CS and HA (500-730 kDa) reduced MMP-3 expression levels at all tested concentrations. Therefore, our study provides new data on the mechanism of action of these drugs, which could help to explain their clinical efficacy in OA patients.

Adjuvants, Immunologic↗

PubMed2004

Timing of follow-up densitometry in hormone replacement therapy users for optimal osteoporosis prevention.

The objectives of the study were (1) to determine the time interval for repeat dual-energy X-ray absorptiometry (DXA) to detect significant bone loss, i.e., greater than the coefficient of variation (CV) of the center (2.8 x CV%) and (2) to assess how long hormone replacement therapy can be maintained to avoid undetected development of low bone mass and to not unduly delay appropriate treatment. A total of 3,826 healthy women, aged 40-65 years, participated in a prospective cohort study, 807 of whom were treated with transdermal estrogen replacement therapy and 626 with transdermal estrogen/progesterone regimens. The untreated group included the remaining 2,393 women. Between 1996 and 2002 they underwent a baseline DXA scan, and DXA scans were then repeated annually. There were no differences among the study groups at entry into the study. Treatment with estrogen was a protective factor for loss of bone mass at the lumbar spine (odds ratio [OR] =0.431, 95% confidence interval [CI] 0.344 to 0.522) and at the femoral neck (OR =0.433, 95% CI 0.352 to 0.521). Treatment with estrogen/progesterone also showed a protective effect against significant changes in follow-up BMD (>2.8 x 1.05% CV of densitometry at L1-L4, >2.8 x 2.3% CV at the femoral neck). In the treated group, significant differences in BMD at the lumbar spine (OR =1.593, 95% CI 1.423 to 2.355) did not appear within the first 3 years, and differences in BMD at the femoral neck (OR =3.555, 95% CI 2.782 to 4.905) did not appear within the first 4 years. It is concluded that in women aged 45-65 years, receiving transdermal hormone replacement therapy without risk factor for loss of bone mass, such as age < 55 years and body mass index <25 kg/m(2), periodical follow-up densitometries would not be necessary, provided that the duration of estrogen or estrogen/progesterone therapy is shorter than 3 years.

Absorptiometry, Photon↗