Browsing by Autor "Marta Benedetti"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item type: Item ,
    Evaluation of a rapid screening method for detection of antimicrobial resistance in the commensal microbiota of the gut
    (Oxford University Press, 2005) Alessandro Bartoloni; Marta Benedetti; Lucia Pallecchi; Mattias Larsson; Antonia Mantella; Marianne Strohmeyer; Filippo Bartalesi; Connie Fernandez; Elisa Guzmán; Yolanda Vallejos
    The assessment of antimicrobial resistance among commensal bacteria is an indicator of the spread of antimicrobial resistance. Rapid screening methods for detection of antimicrobial-resistant faecal Escherichia coli directly on MacConkey plates have been successfully adopted but suffer from lack of standardisation. The purpose of this study was to evaluate a direct plating method (DPM) for detection of antimicrobial-resistant faecal E. coli and to compare it with a conventional method. Faecal samples were collected from 71 healthy children from Peru and Bolivia. In the DPM, a faecal swab was directly plated onto a MacConkey agar plate and antimicrobial disks were applied onto the seeded plate. Raw data were obtained by direct reading of the plate and were subjected to confirmatory analysis. Good concordance between the DPM and a conventional method was observed in detecting carriage of resistant E. coli, with a higher sensitivity for the DPM. Analysis of the results allowed interpretive criteria to be defined for DPM raw data. The DPM showed good sensitivity and specificity at very low cost (ten times cheaper than the conventional method) to investigate the faecal carriage of drug-resistant E. coli. It may represent a useful tool to conduct large-scale resistance surveillance studies and to monitor resistance control programmes cost effectively, particularly in low-resource countries.
  • Thumbnail Image
    Item type: Item ,
    Multidrug-resistant Commensal<i>Escherichia coli</i>in Children, Peru and Bolivia
    (Centers for Disease Control and Prevention, 2006) Alessandro Bartoloni; Lucia Pallecchi; Marta Benedetti; Connie Fernandez; Yolanda Vallejos; Elisa Guzmán; Ana Liz Villagrán; Antonia Mantella; Chiara Lucchetti; Filippo Bartalesi
    Using a rapid screening method, we investigated the prevalence of fecal carriage of antimicrobial drug-resistant Escherichia coli in 3,174 healthy children from 4 urban settings in Peru and Bolivia. High resistance rates were observed for ampicillin (95%), trimethoprim-sulfamethoxazole (94%), tetracycline (93%), streptomycin (82%), and chloramphenicol (70%). Lower resistance rates were observed for nalidixic acid (35%), kanamycin (28%), gentamicin (21%), and ciprofloxacin (18%); resistance to ceftriaxone and amikacin was uncommon (<0.5%). In a random sample of 1,080 resistant E. coli isolates, 90% exhibited a multidrug-resistance (MDR) phenotype. The 2 most common MDR phenotypes (ampicillin/tetracycline/trimethoprim-sulfamethoxazole and ampicillin/tetracycline/trimethoprim-sulfamethoxazole/chloramphenicol) could be transferred en bloc in conjugation experiments. The most common acquired resistance genes were blaTEM, tet(A), tet(B), drfA8, sul1, sul2, and catI. These findings underscore the magnitude of the problem of antimicrobial drug resistance in low-resource settings and the urgent need for surveillance and control of this phenomenon.