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Alvaro Pascual

Publications and source records attributed to Alvaro Pascual.

48 records · Page 3Linked to original sources
PubMed2003

Zinc eluted from siliconized latex urinary catheters decreases OprD expression, causing carbapenem resistance in Pseudomonas aeruginosa.

The activities of carbapenems against Pseudomonas aeruginosa decreased in the presence of siliconized latex urinary catheters (SLUCs). This effect was associated with the loss of OprD. The zinc that eluted from SLUCs is responsible for this phenomenon. We have found that zinc exerts a negative effect on the expression of OprD, the porin responsible for carbapenem entry into P. aeruginosa.

Carbapenems↗
PubMed2003

In vitro activity of azithromycin in combination with amikacin, ceftazidime, ciprofloxacin or imipenem against clinical isolates of Acinobacter baumannii.

The in vitro activity of the two-drug combinations of azithromycin with amikacin, ceftazidime, ciprofloxacin or imipenem against five clonally unrelated strains of Acinobacter baumannii were evaluated. Synergy studies were performed by the checkerboard microtiter method. The fractional inhibitory concentration (FIC) index was calculated for each drug combination. None of the four combinations tested was antagonistic. The combination of azithromycin and ceftazidime was synergistic (FIC index <or=0.5) for one strain and partially synergistic (FIC index 0.75) for another strain. An additive effect (FIC index = 1) was observed for the combinations of azithromycin with imipenem (two strains) or ceftazidime (one strain). The activities of the other combinations were indifferent (FIC index range from 1.5 to 2.5). It is concluded that azithromycin combined with ceftazidime has moderate synergistic activity against some multiresistant A. baumannii.

Acinetobacter baumannii↗
PubMed2003

Effect of linezolid on the phagocytic functions of human polymorphonuclear leukocytes.

The effect of linezolid on the phagocytic and bactericidal functions of human polymorphonuclear neutrophils (PMN) against gram-positive cocci was evaluated. Preincubation (30 min; 37 degrees C) of PMN with different concentrations of linezolid (2, 10 and 20 mg/l) did not significantly affect the phagocytosis of either Staphylococcus aureus (methicillin susceptible and resistant) or Enterococcus faecalis (vancomycin susceptible and resistant). Overnight exposure of vancomycin-resistant E. faecalis to 1/4 minimum inhibitory concentrations (MIC) of linezolid slightly increased phagocytosis by PMN. Preincubation of the other three strains with 1/4 MIC of linezolid did not affect phagocytosis by these cells. Preincubation of PMN (30 min; 37 degrees C) using different extracellular concentrations of linezolid (2, 10 and 20 mg/l) did not affect their production of either superoxide or hydrogen peroxide radicals. In conclusion, linezolid did not affect the phagocytic and bactericidal functions of human PMN.

Acetamides↗
PubMed2003

[Extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in spanish hospitals (GEIH-BLEE Project 2002)].

INTRODUCTION: To describe demographic aspects of a prospective multicentric nationwide study on Escherichia coli and Klebsiella pneumoniae producing extended spectrum b -lactamases (ESBL) in Spain, between March and June 2000. METHODS: 352 E. coli and K. pneumoniae strains showing a phenotype compatible to ESBL production were collected from 40 Spanish Hospitals. A form with demographic and clinical data was filled for every isolate. Identification and susceptibility testing (microdilution, NCCLS guidelines) were performed in a reference centre. RESULTS. 240 strains (170 E. coli and 70 K. pneumoniae) produced ESBL. E. coli ESBL (+) strains were isolated in 33 out of 40 participating hospitals, whereas K. pneumoniae were isolated in 17 hospitals. E. coli ESBL (+) prevalence ranged from 0% to 2.4% and K. pneumoniae ESBL (+) from 0% to 16.7%. Fifty-one percent of E. coli ESBL (+) were from outpatients, whereas 93% of K. pneumoniae ESBL (+) were from inpatients. E. coli ESBL (+) were mainly collected from Medicine and Surgery wards and K. pneumoniae from ICU and Paediatrics. ESBL (+) strains were isolated more frequently from urine samples. Patients' ages ranged from 0 to 93 years for E. coli (median 58 years) and 0 to 83 years for K. pneumoniae (median: 1 year). Paediatric cases excluded, these median values were 64 and 53 years, respectively. CONCLUSIONS: E. coli and K. pneumoniae ESBL (+) were identificated in 90% of the participating hospitals. Although E. coli was more frequently isolated than K. pneumoniae, production of ESBL was more prevalent in K. pneumoniae. Fifty-one percent of ESBL producing E. coli were isolated from outpatients.

Adolescent↗
PubMed2002

Energy-dependent accumulation of norfloxacin and porin expression in clinical isolates of Klebsiella pneumoniae and relationship to extended-spectrum beta-lactamase production.

The relationships between porin deficiency, active efflux of fluoroquinolones, and extended-spectrum beta-lactamase (ESBL) production were determined for 53 clinical isolates of Klebsiella pneumoniae. Thirty-two ESBL-positive strains (including 22 strains expressing porins and 10 strains lacking porins) and 21 ESBL-negative strains were evaluated. Active efflux of norfloxacin was defined as a >/=50% increase in the accumulation of norfloxacin in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) in comparison with the corresponding basal value in the absence of CCCP. The quinolone resistance-determining regions of both gyrA and parC from 13 strains, representing all isolates with different porin profiles and with or without active efflux, were determined. Porin loss was significantly more common among ESBL-positive strains (10 of 32 [31.2%]) than among ESBL-negative strains (0 of 2 [0%]) (P < 0.01). Active efflux was observed in 7 of 10 (70%) strains lacking porins and in 4 of 43 (9.3%) strains producing porins (P < 0.001). The 11 strains showing active efflux corresponded to 3 of 21 (14.3%) ESBL-negative strains and 8 of 32 (25.5%) ESBL-positive strains (P > 0.05). Basal values of norfloxacin accumulation were higher in strains lacking active efflux than in those that had this mechanism (P < 0.05). In the absence of topoisomerase changes, the contribution of either porin loss or active efflux to fluoroquinolone resistance in K. pneumoniae was negligible. It is concluded that among K. pneumoniae strains of clinical origin, porin loss was observed only in those producing ESBL, and that a significant number of porin-deficient strains also expressed active efflux of norfloxacin. In terms of fluoroquinolone resistance, both mechanisms are significant only in the presence of topoisomerase modifications.

Anti-Infective Agents↗
PubMed2002

Uptake and intracellular activity of linezolid in human phagocytes and nonphagocytic cells.

The intracellular penetration and activity of linezolid in human polymorphonuclear leukocytes and tissue-cultured cells (McCoy) were evaluated. Linezolid reached intracellular concentrations slightly greater than extracellular ones in both types of cell. The uptake was rapid and not saturable and was affected by environmental temperature and cell viability. Linezolid showed slight intracellular activity against Staphylococcus epidermidis at high extracellular concentrations.

Acetamides↗
PubMed2002

Comparison of an assay using signal amplification of the heat-dissociated p24 antigen with the Roche Monitor human immunodeficiency virus RNA assay.

We compared an assay using signal amplification of a heat-dissociated p24 antigen (HDAg) with the Roche Monitor human immunodeficiency virus (HIV) RNA assay. The two assays gave comparable results when 130 specimens from 130 patients were tested (r = 0.60, P < 0.0001). The HDAg assay was almost as sensitive (85%) as the Roche HIV RNA kit (95%), just as specific (25 negative results from 25 HIV seronegative volunteers [100%]), less variable (mean log standard deviation of 0.07 compared to 0.11 when eight specimens were tested three or four times), and less expensive (reagent and labor costs, $8 versus $75). The assay appeared to be useful for monitoring established patients (n = 17) and identifying seroconverters (n = 4). HIV subtypes A to F were all recognized. This assay should be useful for monitoring patients in resource-poor countries and for monitoring vaccine recipients.

HIV Core Protein p24↗
PubMed1995

Evaluation of CrystalTM Rapid Stool/Enteric ID System for Identification of Aerobic Gram-negative Bacilli.

OBJECTIVE: The evaluation of the new miniaturized CrystalTM Rapid Stool/Enteric System (Becton-Dickinson, USA) for identification of aerobic gram-negative bacilli. METHODS: a total of 154 clinical organisms (Enterobacteriaceae: 120 strains; oxidase-positive fermenters: 13 strains; non-fermenters: 21 strains) were tested. Results were compared with those obtained with the PASCOR system (Difco, USA) and divergent identifications were evaluated by standard biochemical tests. RESULTS: without additional testing, correct identification was obtained for 146 strains (Enterobacteriaceae: 95%; oxidase-positive fermenters 87%; non-fermenters 100%). For adequate identification of Yersinia enterocolitica strains, however, panels had to be incubated for 5 instead of 3 hours. CONCLUSIONS: the CrystalTM Rapid Stool/Enteric system offers a safe, accurate and rapid method for the identification of frequent isolates of the family Enterobacteriaceae and bacterial stool pathogens.

Journal Article↗