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Alvaro Pascual

Publications and source records attributed to Alvaro Pascual.

At least 19 recordsLinked to original sources
PubMed2007

Analysis of plasmids encoding extended-spectrum beta-lactamases (ESBLs) from Escherichia coli isolated from non-hospitalised patients in Seville.

Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli is an emerging pathogen in the community. We investigated the specific types of ESBLs in E. coli isolates from non-hospitalised patients and the plasmids harbouring these ESBLs. Forty-eight consecutive ESBL-producing E. coli were studied. All the isolates were clonally unrelated. ESBLs were characterised by sequencing. Mobility of the undigested plasmids was investigated both by conventional electrophoresis and by pulsed-field gel electrophoresis. Southern restriction fragment length polymorphism (RFLP) experiments were carried out by digesting plasmids with EcoRI and HindIII. CTX-M-14 was the most frequent ESBL (28 isolates), followed by SHV-12 (16 isolates). Plasmids encoding CTX-M-14 appeared homogeneous both in hybridisation profile and mobility. In contrast, plasmids expressing SHV-12 were more varied in size and hybridisation patterns. Our data suggest that a single type or very closely related plasmids harbouring CTX-M-14 are spreading in the community among unrelated E. coli isolates in our area.

Blotting, Southern↗
PubMed2006

Bacteremia due to extended-spectrum beta -lactamase-producing Escherichia coli in the CTX-M era: a new clinical challenge.

BACKGROUND: Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli, particularly those producing CTX-M types of ESBL, are emerging pathogens. Bacteremia caused by these organisms represents a clinical challenge, because the organisms are frequently resistant to the antimicrobials recommended for treatment of patients with suspected E. coli sepsis. METHODS: A cohort study was performed that included all episodes of bloodstream infection due to ESBL-producing E. coli during the period from January 2001 through March 2005. Data on predisposing factors, clinical presentation, and outcome were collected. ESBLs were characterized using isoelectric focusing, polymerase chain reaction, and sequencing. RESULTS: Forty-three episodes (8.8% of cases of bacteremia due to E. coli) were included; 70% of the isolates produced a CTX-M type of ESBL. The most frequent origins of infection were the urinary (46%) and biliary tracts (21%). Acquisition was nosocomial in 21 cases (49%), health care associated in 14 cases (32%), and strictly community acquired in 8 cases (19%). Thirty-eight percent and 25% of patients had obstructive diseases of the urinary and biliary tracts, respectively, and 38% had recently received antimicrobials. Nine patients (21%) died. Compared with beta-lactam/beta-lactamase-inhibitor and carbapenem-based regimens, empirical therapy with cephalosporins or fluoroquinolones was associated with a higher mortality rate (9% vs. 35%; P=.05) and needed to be changed more frequently (24% vs. 78%; P=.001). CONCLUSIONS: ESBL-producing E. coli is a significant cause of bloodstream infection in hospitalized and nonhospitalized patients in the context of the emergence of CTX-M enzymes. Empirical treatment of sepsis potentially caused by E. coli may need to be reconsidered in areas where such ESBL-producing isolates are present.

Adult↗
PubMed2006

The Meropenem Yearly Susceptibility Test Information Collection antimicrobial susceptibility program in Spain: a 5-year analysis.

The Meropenem Yearly Susceptibility Test Information Collection program is a global study providing in vitro surveillance data on antimicrobial susceptibility in centers prescribing meropenem. This study summarizes data on the activity of meropenem and 5 comparators against 4022 clinical isolates from 7 centers in Spain (1999-2003). Those bacteria intrinsically resistant to meropenem were excluded. Among Enterobacteriaceae, 100% of Enterobacter spp., Citrobacter spp., and Serratia spp. were susceptible to meropenem. Escherichia coli and Klebsiella pneumoniae susceptibilities to carbapenems were 100% and > or =98%, respectively. Extended-spectrum beta-lactamase-producing Enterobacteriaceae were 3.8% of isolates, and all of them were susceptible to meropenem. Ciprofloxacin resistance in E. coli was around 20%. Meropenem and piperacillin/tazobactam were the most active agents against Pseudomonas aeruginosa. Acinetobacter baumannii were 61-90% susceptible to carbapenems, but only 6-21% susceptible to ciprofloxacin. In this period, around 100% of oxacillin-susceptible staphylococci were susceptible to meropenem. There was no significant decrease in susceptibility to the carbapenems throughout the 5-year period. The clinical use of meropenem in 7 Spanish centers did not increase bacterial resistance to this agent in the microorganisms evaluated.

Academic Medical Centers↗
PubMed2006

Comparative in vitro activity of ertapenem against extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolated in Spain.

The in vitro activity of ertapenem was tested against extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae isolated in Spain. Ertapenem activity was similar to that of imipenem and meropenem and better than that of the other antimicrobials tested. No differences in activity were observed regarding the origin of the isolates or type of ESBL produced.

Anti-Bacterial Agents↗
PubMed2006

Prevention of rifampicin resistance in Acinetobacter baumannii in an experimental pneumonia murine model, using rifampicin associated with imipenem or sulbactam.

OBJECTIVES: To examine the development of rifampicin resistance in multidrug-resistant Acinetobacter baumannii exposed to rifampicin and the prevention of the appearance of rifampicin-resistant mutants when rifampicin is used in association with imipenem or sulbactam. METHODS: A clinical strain of multidrug-resistant A. baumannii was used to examine the frequency of resistance to rifampicin in vivo, in a pneumonia model in immunocompetent C57BL/6 mice. The in vitro and in vivo prevention of the development of resistance to rifampicin was analysed using rifampicin alone or in association with imipenem or sulbactam, in time-kill studies and in the experimental murine pneumonia, respectively. RESULTS: Rifampicin-resistant mutants were found at 48 and 72 h, both in vitro and in vivo, when rifampicin was used alone, with the MIC increasing from 4 to > or =128 mg/L. The in vivo frequency of rifampicin-resistant mutants was 3 x 10(-6). On the contrary, no resistant mutants appeared after 72 h, in vitro or in vivo, when rifampicin was employed in association with imipenem or sulbactam. After six daily passages in rifampicin-free agar plates the resistant mutants maintained the high resistance to rifampicin (> or =128 mg/L). CONCLUSIONS: These results suggest that rifampicin must not be used alone in the treatment of infections caused by multidrug-resistant A. baumannii. In these cases, rifampicin may be used in combination with imipenem or sulbactam, which prevent the development of resistance to rifampicin.

Acinetobacter Infections↗
PubMed2006

In vivo selection of Enterobacter aerogenes with reduced susceptibility to cefepime and carbapenems associated with decreased expression of a 40 kDa outer membrane protein and hyperproduction of AmpC beta-lactamase.

The mechanism(s) of resistance or decreased susceptibility to cefepime (FEP) and/or imipenem (IMP) in three consecutive isolates of Enterobacter aerogenes (Ea1, Ea2 and Ea3) cultured from bronchial aspirates of the same patient after treatment with ceftriaxone and FEP were studied. Identification was performed with the VITEK 2 system. All three isolates showed identical pulsed-field gel electrophoresis patterns and were resistant (minimum inhibitory concentrations (MICs)) to cefoxitin (MIC, >1024 mg/L), cefotaxime (CTX; MIC, 32-128 mg/L) and ceftazidime (CAZ; MIC, 32-128 mg/L) but susceptible to meropenem (MIC, Glu. Three outer membrane proteins (OMPs) of 51 kDa, 40 kDa and 38 kDa were observed in the three isolates by sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) (10% polyacrylamide gels with 4 M urea), although expression of the 40 kDa OMP was reduced in Ea2. In conclusion, decreased susceptibility to FEP and IMP in Ea2 is related to reduced expression of a 40 kDa OMP and hyperproduction of AmpC, whereas resistance to FEP in Ea3 is associated with hyperproduction of an altered AmpC.

Anti-Bacterial Agents↗
PubMed2006

Plasmid-mediated quinolone resistance in Australia.

The aim of this study was to search for plasmid-encoded quinolone resistance determinants QnrA and QnrS in fluoroquinolone-resistant and extended-spectrum beta-lactamase (ESBL)-producing enterobacterial isolates recovered in Sydney, Australia, in 2002. Twenty-three fluoroquinolone-resistant, of which 16 were also ESBL-positive, enterobacterial and nonrelated isolates were studied. PCR with primers specific for qnrA and qnrS genes and primers specific for a series of ESBL genes were used. A qnrA gene was identified in two ESBL-positive isolates, whereas no qnrS-positive strain was found. The QnrA1 determinant was identified in an Enterobacter cloacae isolate and in a carbapenem-resistant Klebsiella pneumoniae isolate, both of which expressed the same ESBL SHV- 12. Whereas no plasmid was identified in the E. cloacae isolate, K. pneumoniae K149 possessed two conjugative plasmids, one that harbored the qnrA and bla (SHV)-12 genes whereas the other expressed the carbapenemase gene bla (IMP-4). The qnrA gene, was located in both cases downstream of the orf513 recombinase gene and upstream of the qnrA1 gene, a structure identical to that found in sul1-type integron In36 and qnrA-positive strains from Shanghai, China. However, the gene cassettes of the sul1-type integrons were different. This study identified the first plasmid-mediated quinolone resistance determinant in Enterobacteriaceae in Australia.

Anti-Bacterial Agents↗
PubMed2006

Intracellular penetration and activity of DX-619 in human polymorphonuclear leukocytes.

The intracellular penetration and activity of DX-619 in human polymorphonuclear leukocytes have been evaluated. DX-619 reached intracellular concentrations 10 times higher than the extracellular concentrations reached. Uptake was rapid, reversible, nonsaturable, and affected by environmental temperature, some metabolic inhibitors, and a soluble membrane activator. DX-619 showed intracellular activity against Staphylococcus aureus.

Cells, Cultured↗
PubMed2006

[Epidemiology, clinical features and prognosis of infections due to Stenotrophomonas maltophilia].

INTRODUCTION: Stenotrophomonas maltophilia is a multiresistant pathogen that is being isolated with increasing frequency from patients with predisposing factors. Few studies have assessed the epidemiology and clinical relevance of this pathogen in various types of patients from general hospitals. METHODS: This is a prospective study performed in the cohort of patients with infection due to S. maltophilia in Hospital Univeritario Virgen Macarena (Seville, Spain) between January 1998 and January 2001. The following data were collected: demographics, underlying diseases, APACHE II score at admission, invasive procedures, previous antimicrobial treatment, systemic response, therapy and outcome. RESULTS: S. maltophilia was isolated from a clinical sample in 87 patients and was considered to be the cause of infection in 45 (52%) of them, who were included in the study. Among the total, 40% were in the ICU and 13% were outpatients. The infection was considered health care-associated in 91%; 82% had received antimicrobial treatment. The most frequent type of infection was pneumonia, followed by other infections of the respiratory tract, urinary tract infections, and skin and soft tissue infections. Criteria for severe sepsis or septic shock were present in 12%. The most common antimicrobials used were the combination trimethoprim-sulfamethoxazole (60%). Crude mortality was 44% and the only associated variable was the APACHE II score. Infection-related mortality was 13%; all deaths occurred in patients with pneumonia. CONCLUSION: S. maltophilia caused a wide range of health care-associated infections in debilitated patients, even though half the patients from whom the organism was isolated were considered only colonized. Crude mortality was associated with the severity of the baseline situation. Pneumonia was associated with high mortality.

Adolescent↗
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↗
PubMed2006

[Activity of fosfomycin against extended-spectrum beta-lactamase producing Escherichia coli and Klebsiella pneumoniae].

INTRODUCTION: Infection due to extended-spectrum beta-lactamase (ESBL)-producing microorganisms is an emerging problem in the community; a high proportion of these microorganisms have been isolated from urine samples of women with uncomplicated urinary tract infections (UTI). The options for oral treatment of uncomplicated UTI are limited because of the multiple drug resistance typical of ESBL-producing strains. METHODS: The in vitro activity of fosfomycin (FOS) was determined against 428 ESBL-producing strains, including 290 (68%) E. coli and 138 (32%) K. pneumoniae. Activity of fosfomycin was compared with that of amoxicillin-clavulanate (AMC), ciprofloxacin (CIP) and cotrimoxazole (SxT). MICs of AMC, CIP, and SxT, and detection of ESBL production were tested by the broth microdilution method, whereas FOS MICs were determined by the agar dilution method. ESBLs were characterized by isoelectric focusing, polymerase chain reaction (PCR) and direct sequencing of encoding genes. The genetic relationship among the isolates was determined by REP-PCR. RESULTS: Among the 428 ESBL-producing isolates studied, 417 (97.4%) were susceptible to FOS (MIC < or = 64 microg/mL). The resistance rate of E. coli to FOS was 0.3%, and was lower than resistance to AMC (11.7%), whereas the resistance rate of K. pneumoniae was 7.2% and was equal to resistance to AMC. SxT and CIP were the least active antibiotic agents against ESBL-producing isolates (sensitivity < 50%). There were no differences in fosfomycin activity against strains expressing different types of ESBLs. CONCLUSION: Fosfomycin showed maintained activity against ESBL-producing strains and did not present co-resistance with other antimicrobial groups.

Amoxicillin-Potassium Clavulanate Combination↗
PubMed2005

Clinical and molecular epidemiology of extended-spectrum beta-lactamase-producing Escherichia coli as a cause of nosocomial infection or colonization: implications for control.

BACKGROUND: Extended-spectrum beta-lactamase (ESBL)-producing members of the Enterobacteriaceae family are important nosocomial pathogens. Escherichia coli producing a specific family of ESBL (the CTX-M enzymes) are emerging worldwide. The epidemiology of these organisms as causes of nosocomial infection is poorly understood. The aims of this study were to investigate the clinical and molecular epidemiology of nosocomial infection or colonization due to ESBL-producing E. coli in hospitalized patients, consider the specific types of ESBLs produced, and identify the risk factors for infection and colonization with these organisms. METHODS: All patients with nosocomial colonization and/or infection due to ESBL-producing E. coli in 2 centers (a tertiary care hospital and a geriatric care center) identified between January 2001 and May 2002 were included. A double case-control study was performed. The clonal relatedness of the isolates was studied by repetitive extragenic palindromic-polymerase chain reaction and pulsed-field gel electrophoresis. ESBLs were characterized by isoelectric focusing, polymerase chain reaction, and sequencing. RESULTS: Forty-seven case patients were included. CTX-M-producing E. coli were clonally unrelated and more frequently susceptible to nonoxyimino-beta-lactams. Alternately, isolates producing SHV- and TEM-type ESBL were epidemic and multidrug resistant. Urinary catheterization was a risk factor for both CTX-M-producing and SHV-TEM-producing isolates. Previous oxyimino-beta-lactam use, diabetes, and ultimately fatal or nonfatal underlying diseases were independent risk factors for infection or colonization with CTX-M-producing isolates, whereas previous fluoroquinolone use was associated with infection or colonization with SHV-TEM-producing isolates. CONCLUSIONS: The epidemiology of ESBL-producing E. coli as a cause of nosocomial infection is complex. Sporadic CTX-M-producing isolates coexisted with epidemic multidrug-resistant SHV-TEM-producing isolates. These data should be taken into account for the design of control measures.

Adult↗
PubMed2005

Uptake and intracellular activity of voriconazole in human polymorphonuclear leucocytes.

OBJECTIVES: The intracellular penetration of voriconazole into human polymorphonuclear leucocytes (PMNs) and its intracellular activity against Candida spp. were evaluated. METHODS: The intracellular penetration of voriconazole into PMNs was evaluated by a radiometric assay. The effect of cell viability, environmental conditions, metabolic inhibitors and membrane stimulation was also studied. The intracellular activity was determined by incubation of PMNs containing intracellular blastospores in the presence of voriconazole for 3 h. RESULTS: The uptake of voriconazole by PMNs was rapid and not saturable. The cellular to extracellular concentration (C/E) ratio for voriconazole was 8.5+/-1.3. Voriconazole was rapidly released from loaded PMNs. The uptake of voriconazole was not affected by environmental temperature and cell viability. Neither the external pH nor the metabolic inhibitors affected the uptake of voriconazole. The ingestion of opsonized zymosan, but not of opsonized Candida spp., significantly decreased the levels of PMN-associated voriconazole. At the extracellular concentrations evaluated, voriconazole did not affect the intracellular survival of Candida. CONCLUSIONS: Voriconazole reached high intracellular concentrations within human PMNs. The uptake was rapid and not saturable but it did not affect the intracellular killing of Candida spp.

Antifungal Agents↗