Teresa Peláez

Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Madrid, Spain

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Publications (102)389.42 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To longitudinally assess the shedding of antimicrobial resistant Clostridium difficile strains by clinically healthy dogs raised at breeding facilities. 18 puppies from three different litters (#1, 2 and 3) were sampled weekly from parturition to day 20-55 postpartum. Faecal samples from the mothers of litters #2 and 3 were also available for analysis. Bacterial isolates were ribotyped, tested for in vitro antimicrobial susceptibility and further characterised. C. difficile was recovered from all sampled animals of litters #1 and 2, and a third of puppies from litter #3, but marked differences in C. difficile recovery were detected in different age groups (0-100%). Recovered PCR ribotypes included 056 (22 isolates), 010 (6 isolates), 078 and 213 (2 isolates each), and 009 and 020 (1 isolate each). Different ribotypes were shed by four individual animals. Regardless of their origin and ribotype, all isolates demonstrated full resistance to levofloxacin. Additionally, all but one isolate (belonging to ribotype 078) were resistant to ertapenem, and all ribotype 010 isolates displayed high-level resistance to clindamycin, clarithromycin and erythromycin. A single ribotype 078 isolate showed metronidazole heteroresistance. Healthy dogs can shed antimicrobial-resistant C. difficile strains. © 2014 British Small Animal Veterinary Association.
    Journal of Small Animal Practice 12/2014; · 1.18 Impact Factor
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    ABSTRACT: We studied whether STRAf can differentiate between A. fumigatus invasive and colonizing genotypes. Of the 395 genotypes detected (n=1,373 isolates), 50 were clusters, and 24 (6% of all genotypes) involved both patients with invasive aspergillosis and colonized patients, indicating that genotyping cannot discriminate between invasive and colonizing isolates. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
    Journal of clinical microbiology. 11/2014;
  • Enfermedades Infecciosas y Microbiología Clínica 07/2014; · 1.48 Impact Factor
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    ABSTRACT: We assessed the in vitro activity of micafungin against preformed Candida biofilms by measuring the concentration of drug causing the most fungal damage and inhibition of regrowth. We studied 37 biofilm-producing Candida spp. strains from blood cultures. We showed that micafungin was active against planktonic and sessile forms of C. albicans strains and moderately active against C. parapsilosis sessile cells. Concentrations of micafungin above 2 μg/mL were sufficiently high to inactivate regrowth of Candida sessile cells.
    Antimicrobial Agents and Chemotherapy 06/2014; · 4.57 Impact Factor
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    ABSTRACT: Catheter-related candidemia (CRC) is typically a biofilm related disease, but it is mostly unknown if the production of biofilm is a feature exclusively shown by Candida spp. isolates causing CRC. We performed an in vitro biofilm assay using Candida isolates obtained from the blood of patients with candidemia. We demonstrated that biofilm production was not a good predictor of catheter-related candidemia. Also, we demonstrated that there was no difference in the mortality of candidemia patients infected by biofilm-forming isolates and those in which the infection is caused by nonbiofilm-forming species.
    Medical mycology: official publication of the International Society for Human and Animal Mycology 04/2014; · 2.13 Impact Factor
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    ABSTRACT: We determined the in vitro amphotericin B susceptibility of 60 Malassezia pachydermatis isolates by the CLSI broth microdilution method and the Etest using lipid-enriched media. All isolates were susceptible at a MIC ≤1 μg/ml, confirming the high activity of amphotericin B against this yeast species. Overall essential agreement between the tested methods was high (80% and 96.7% after 48 h and 72 h, respectively) and all discrepancies were regarded as non-substantial differences.
    Antimicrobial Agents and Chemotherapy 04/2014; · 4.57 Impact Factor
  • Journal of Medical Microbiology 01/2014; · 2.30 Impact Factor
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    ABSTRACT: Although ECVs (epidemiologic cutoff values) have been established for Candida spp. and the triazoles, they are based on MIC data from a single laboratory. We have established ECVs for eight Candida species and fluconazole, posaconazole and voriconazole based on wild-type (WT) MIC distributions for isolates of C. albicans (11, 241), C. glabrata (7, 538), C. parapsilosis (6, 023), C. tropicalis (3, 748), C. krusei (1, 073), C. lusitaniae (574), C. guilliermondii (373), and C. dubliniensis (162). The 24-h CLSI broth microdilution MICs were collated from multiple laboratories (Canada, Brazil, Europe, Mexico, Peru, and the United States). ECVs for distributions originating from ≥6 laboratories, which included ≥95% of the modelled WT population (fluconazole, posaconazole, and voriconazole, respectively) were: 0.5, 0.06 and 0.03 μg/ml for C. albicans; 0.5, 0.25, and 0.03 μg/ml for C. dubliniensis; 8, 1 and 0.25 μg/ml for C. glabrata; 8, 0.5 and 0.12 μg/ml for C. guilliermondii; 32, 0.5 and 0.25 μg/ml for C. krusei; 1, 0.06 and 0.06 μg/ml for C. lusitaniae; 1, 0.25 and 0.03 μg/ml for C. parapsilosis; and 1, 0.12 and 0.06 μg/ml for C. tropicalis. The low number of MICs (<100) for other less prevalent species (C. famata, C. kefyr, C. orthopsilosis, C. rugosa) precluded ECV definition, but their MIC distributions are documented. Evaluation of our ECVs for some species/agent combinations using published individual MICs for 136 isolates (harbouring mutations in or up-regulation of ERG11, MDR1, CDR1 and CDR2) and 64 WT isolates indicated that our ECVs may be useful in distinguishing WT from non-WT isolates.
    Antimicrobial Agents and Chemotherapy 01/2014; · 4.57 Impact Factor
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    ABSTRACT: Clostridium difficile is an emerging and potentially zoonotic pathogen, but its prevalence in most animal species, including exhibition animals, is currently unknown. In this study we assessed the prevalence of faecal shedding of C. difficile by zoo animals, and determined the ribotype, toxin profile and antimicrobial susceptibility of recovered isolates. A total of 200 samples from 40 animal species (36.5% of which came from plains zebra, Equus quagga burchellii) were analysed. C. difficile was isolated from 7 samples (3.5% of total), which came from the following animal species: chimpanzee (Pan troglodytes troglodytes), dwarf goat (Capra hircus), and Iberian ibex (Capra pyrenaica hispanica), with one positive sample each; and plains zebra, with 4 positive samples from 3 different individuals. Most recovered isolates (4/7, 57.1%) belonged to the epidemic PCR ribotype 078, produced toxins A and B, and had the genes encoding binary toxin (i.e. A(+)B(+)CDT(+) isolates). The remaining three isolates belonged to PCR ribotypes 039 (A(-)B(-)CDT(-)), 042 (A(+)B(+)CDT(-)) and 110 (A(-)B(+)CDT(-)). Regardless of their ribotype, all isolates displayed high-level resistance to the fluoroquinolones ciprofloxacin, enrofloxacin and levofloxacin. Some isolates were also resistant to meropenem and/or ertapenem. A ribotype 078 isolate recovered from a male zebra foal initially showed in vitro resistance to metronidazole (MIC≥256μg/ml), but lost that trait after subculturing on non-selective media. We conclude that zoo animals belonging to different species can carry ribotype 078 and other toxigenic strains of C. difficile showing resistance to antimicrobial compounds commonly used in veterinary and/or human medicine.
    Veterinary Microbiology 01/2014; · 3.13 Impact Factor
  • Enfermedades Infecciosas y Microbiología Clínica 01/2014; · 1.48 Impact Factor
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    ABSTRACT: Since epidemiological cutoff values (ECVs) using CLSI MICs from multiple laboratories are not available for Candida spp. and the echinocandins, we established ECVs for anidulafungin and micafungin based on wild-type (WT) MIC distributions (organisms in a species-drug combination with no detectable acquired resistance mechanisms) for 8,210 Candida albicans, 3,102 C. glabrata, 3,976 C. parapsilosis, 2,042 C. tropicalis, 617 C. krusei, 258 C. lusitaniae, 234 C. guilliermondii, and 131 C. dubliniensis isolates. CLSI broth microdilution MIC data gathered from 15 different laboratories in Canada, Europe, Mexico, Peru, and the United States were aggregated to statistically define ECVs. ECVs encompassing 97.5% of the statistically-modeled population (anidulafungin and micafungin, respectively) were 0.12 and 0.03 μg/mL for C. albicans, 0.12 and 0.03 μg/mL for C. glabrata, 8 and 4 μg/mL for C. parapsilosis, 0.12 and 0.06 μg/mL for C. tropicalis, 0.25 and 0.25 μg/mL for C. krusei, 1 and 0.5 μg/mL for C. lusitaniae, 8 and 2 μg/mL for C. guilliermondii, and 0.12 and 0.12 μg/mL for C. dubliniensis. Previously reported single and the multicenter ECVs defined in the present study were quite similar or within 1 two-fold dilution from each other. For a collection of 230 WT (no fks mutations) and 51 isolates with fks mutations, the species-specific ECVs for anidulafungin and micafungin correctly classified 47 (92.2%) and 51 (100%) of the fks mutants, respectively, as non-WT strains. These ECVs may aid in detecting non-WT isolates with reduced susceptibility to anidulafungin and micafungin due to fks mutations.
    Antimicrobial Agents and Chemotherapy 11/2013; · 4.57 Impact Factor
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    ABSTRACT: Clostridium difficile ribotype 027 (Cd027) has caused outbreaks in the United States, Canada, and Europe since 2001. In Spain, the importance of Cd027 is still unknown. In 2007, we began active surveillance of Cd027 to determine its incidence in our hospital. From January 2007 to April 2012, isolates of C. difficile by multiplex PCR were studied to detect toxin genes. Binary toxin-positive isolates were characterized using PCR-ribotyping. Cd027 were further characterized by toxino-typing, sequencing of tcdC gene, and MLVA (multilocus-variable-number-tandem-repeat-analysis). Only 8 strains were Cd027 from 3666 isolates of C. difficile analyzed during the study period. These strains were isolated from 4 patients: a Spanish patient previously hospitalized in the UK, a pregnant laboratory technician, a British tourist, and a Spanish patient without epidemiological antecedents for acquiring Cd027. MLVA typing of Cd027 isolates revealed 4 different patterns. The first patient had 2 episodes of diarrhea caused by different Cd027. The strains from the first episode of patient 1 and the strain from patient 2 were grouped in the same clonal cluster (these cases were previously published as laboratory transmission), while strains from patients 3 and 4 were genetically unrelated to each other, and to the strains from patients 1 and 2. We report the first finding of an autochthonous case of non-severe Cd027 infection. Our results indicate that Cd027 diarrhea is uncommon in our area, and it appears mainly as imported cases. MLVA typing enables us to distinguish different genotypes among our Cd027 isolates.
    Enfermedades Infecciosas y Microbiología Clínica 09/2013; · 1.48 Impact Factor
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    ABSTRACT: Although CLSI clinical breakpoints (CBPs) are available for interpreting echinocandin MICs for Candida spp., epidemiologic cutoff values (ECVs) based on collective MIC data from multiple laboratories have not been defined. While collating CLSI caspofungin MICs for 145 to 11,550 Candida isolates from 17 laboratories (Brazil, Canada, Europe, Mexico, Peru and the United States), we observed an extraordinary amount of modal variability (wide ranges) among laboratories as well as truncated and bimodal MIC distributions. The species-specific modes across different laboratories ranged from: 0.016-0.5 μg/ml for C. albicans and C. tropicalis; 0.031-0.5 μg/ml for C. glabrata; 0.063-1 μg/ml for C. krusei; variability was also similar among C. dubliniensis and C. lusitaniae. The exceptions were C. parapsilosis and C. guilliermondii MIC distributions, where most modes were within one twofold dilution of each other. These findings were consistent with available EUCAST data (403 to 2,556 MICs) for C. albicans, C. glabrata, C. krusei, and C. tropicalis. Although many factors (caspofungin powder source, stock solution solvent, powder storage time length and temperature, and MIC determination testing parameters) were examined as a potential cause of such unprecedented variability, a single specific cause was not identified. Therefore, it seems highly likely that the use of the CLSI species-specific caspofungin CBPs could lead to reporting an excessive number of wild-type [WT] (e.g., C. glabrata and C. krusei) as either non-WT or resistant isolates. Until this problem is resolved, routine testing or reporting of CLSI caspofungin MICs for Candida is not recommended; micafungin or anidulafungin data could be used instead.
    Antimicrobial Agents and Chemotherapy 09/2013; · 4.57 Impact Factor
  • E Bouza, M Marín, T Peláez, L Alcalá
    Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 09/2013; 26(3):261-286. · 0.84 Impact Factor
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    ABSTRACT: A population-based survey was conducted to investigate the epidemiology and the antifungal resistance in Spanish clinical strains of filamentous fungi isolated from deep tissue samples, blood cultures and respiratory samples. The study was conducted in two different periods (October 2010 and May 2011) to analyze seasonal variations. A total of 325 strains were isolated in 29 different hospitals. Average prevalence was 0.0016/1,000 habitants. Strains were identified by sequencing of DNA targets and susceptibility testing by EUCAST reference procedure. The most frequent genus was Aspergillus accounting for 86.3% of the total isolates, followed by Scedosporium 4.7%; Mucorales 2.5%; Penicillium 2.2%, and Fusarium, 1.2%. The most frequent species was Aspergillus fumigatus (48.5%), followed by A. flavus (8.4%), A. terreus (8.1%), A. tubingensis (6.8%) and A. niger (6.5%). Cryptic/sibling species of Aspergillus accounted for 12% of total cases. Resistance to amphotericin B was found in 10.8% of isolates, while extended spectrum triazole resistance ranged between 10 to 12.7% depending on the azole tested. Antifungal resistance was more common among emerging species such as Scedosporium and Mucorales and also among cryptic species of Aspergillus with a 40% of these isolates showing resistance to all antifungal compounds tested. Cryptic Aspergillus species seems to be underestimated and their correct classification could be clinically relevant. Performing antifungal susceptibility testing of the strains implicated in deep infections and multicentric studies are recommended to evaluate the incidence of these cryptic species in other geographical areas.
    Antimicrobial Agents and Chemotherapy 08/2013; · 4.57 Impact Factor
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    ABSTRACT: Candida tropicalis ranks between third and fourth among Candida species most commonly isolated from clinical specimens. Invasive candidiasis and candidemia are treated with amphotericin B or echinocandins as first-line therapy, with extended-spectrum triazoles as acceptable alternatives. Candida tropicalis is usually susceptible to all antifungal agents although several azole drug resistant clinical isolates are being reported. However, C. tropicalis resistant to amphotericin B is uncommon and only a few strains have reliably demonstrated a high resistance level to this agent. The resistance mechanisms operating in C. tropicalis strains isolated from clinical samples showing resistance to azole drugs alone or joined to amphotericin B cross-resistance were elucidated. Antifungal drug resistance was related to mutations of the azole target (Erg11p) with or without alterations of the ergosterol biosynthesis pathway. The antifungal drug resistance shown in vitro correlated very well with the results obtained in vivo using the model host Galleria mellonella. Using this panel of strains, the G. mellonella model system was validated as a simple, non-mammalian, mini host model that can be used to study in vitro/in vivo correlation of antifungals in C. tropicalis. The development of C. tropicalis antifungal drug resistance with different mechanisms during antifungal treatment has potential clinical impact and deserves specific prospective studies.
    Antimicrobial Agents and Chemotherapy 07/2013; · 4.57 Impact Factor
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    ABSTRACT: Previous studies in intensively raised piglets have detected a high prevalence of the epidemic Clostridium difficile PCR ribotype 078. In this article we present a longitudinal survey of C. difficile colonisation in a population of Iberian pigs reared under a free-range system. A total of 160 faecal samples from 20 piglets belonging to different litters were obtained by weekly sampling. C. difficile was recovered from samples collected at different times throughout the survey from a 90% of piglets, resulting in an overall prevalence of 25.6% in the studied samples. Most positive samples (75.6%) came from ⩽15-day animals, but some piglets shed C. difficile even on day +50. All isolates were ribotype 078, harboured toxin-encoding genes and showed in vitro resistance to several fluoroquinolones. A majority of isolates (80.5%) were also high-level resistant to ertapenem, and four metronidazole heteroresistant isolates (9.8%) were detected. In conclusion, Iberian free-range pigs can be a potential reservoir of epidemic antimicrobial-resistant strains of C. difficile, showing a prevalence rate similar to that found for intensively raised animals.
    Research in Veterinary Science 07/2013; · 1.77 Impact Factor
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    ABSTRACT: We retrospectively studied 22 patients with catheter-related candidemia caused by Candida albicans. Strains isolated simultaneously from blood and catheter tips were genotyped using six microsatellite markers. Matches between genotypes of isolates recovered from both sample sources were found in 20/22 (91%) patients. Consequently, identification of the same species from both the catheter tip and blood could be used to confirm catheter-related candidemia.
    Medical mycology: official publication of the International Society for Human and Animal Mycology 07/2013; · 2.13 Impact Factor
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    ABSTRACT: Clostridium difficile is an emerging pathogen for humans and animals and there is concern about the possibility that livestock might serve as a reservoir of epidemic strains. In Spain, ribotype 078 is one of the most prevalent in human episodes of C. difficile infection, but the distribution of this and other ribotypes in animals is yet unknown. We present the first report on the ribotype distribution and antimicrobial susceptibility of C. difficile in swine in Spain. A total of 144 isolates were PCR ribotyped, and their MIC values for 13 antimicrobial agents were determined using the Etest. Toxin A and B production was assessed using a commercial immunoassay and, in the case of toxin B, a specific cytotoxicity test. Our results show a high prevalence of the toxigenic 078 ribotype (94.4%) and multidrug resistance (49.3%) among the studied isolates. A minority of isolates (5.6%) belonged to a mostly non-toxinogenic ribotype. All isolates were resistant to the fluoroquinolone ciprofloxacin, but susceptible to daptomycin, linezolid, meropenem, rifampicin, teicoplanin, tigecycline, metronidazole and vancomycin. Resistance to clindamycin, ertapenem, erythromycin and moxifloxacin was common (≥ 27.8% in all cases). Resistance rates for the different antibiotics tested were in all cases independent from the ribotype of isolates and the host's condition (diarrheic or non-diarrheic), but erythromycin and moxifloxacin resistance was associated with the geographic origin of isolates. Metronidazole heteroresistance was found among animal isolates of C. difficile. Our results highlight the role of livestock as a potential source of epidemic multidrug resistant strains in Spain.
    Anaerobe 06/2013; · 2.02 Impact Factor
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    ABSTRACT: Epidemiologic cutoff values (ECVs) were established for the new triazole isavuconazole and Aspergillus spp. Wild type (WT) MIC distributions (organisms in a species/drug combination with no detectable acquired resistance mechanisms) were defined with the available isolates of the following Aspergillus species complexes: 855 A. fumigatus, 444 A. flavus, 106 A. nidulans, 207 A. niger, 384 A. terreus, and 75 A. versicolor; 29 Aspergillus section Usti isolates were also included. CLSI broth microdilution MIC data gathered in Europe, India, Mexico and the United States were aggregated to statistically define ECVs. ECVs expressed in μg/ml were: A. fumigatus species complex 1; A. flavus species complex 1; A. nidulans species complex 0.25; A. niger species complex 4, A. terreus species complex 1 and A. versicolor species complex 1; due to the low number of isolates, an ECV was not proposed for Aspergillus section Usti. These ECVs may aid in detecting isavuconazole non-WT isolates with reduced susceptibility to this agent due to cyp51A (an A. fumigatus species complex resistance mechanism among the triazoles) or other mutations.
    Antimicrobial Agents and Chemotherapy 05/2013; · 4.57 Impact Factor

Publication Stats

2k Citations
389.42 Total Impact Points


  • 2012–2014
    • Instituto de Investigación Sanitaria Gregorio Marañón
      Madrid, Madrid, Spain
    • University of Iowa
      Iowa City, Iowa, United States
  • 1997–2014
    • Complutense University of Madrid
      Madrid, Madrid, Spain
  • 1991–2014
    • Hospital General Universitario Gregorio Marañón
      • • Servicio de Aparato Digestivo
      • • Clinical Microbiology and Infectious Diseases
      • • Servicio de Microbiología
      • • Department of Clinical Microbiology
      Madrid, Madrid, Spain
  • 2013
    • JMI Laboratories
      North Liberty, Iowa, United States
  • 2010–2013
    • Richmond VA Medical Center
      Richmond, Virginia, United States
  • 2011
    • University of Adelaide
      Tarndarnya, South Australia, Australia