Browsing by Autor "Lucia Pallecchi"

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Carriage of Antibiotic-Resistant Escherichia coli Among Healthy Children and Home-Raised Chickens: A Household Study in a Resource-Limited Setting
(Mary Ann Liebert, Inc., 2011) Eleonora Riccobono; Lucia Pallecchi; Antonia Mantella; Filippo Bartalesi; Ignacio Chavez Zeballos; Christian Trigoso; Ana Liz Villagrán; Alessandro Bartoloni; Gian María Rossolini
We have previously observed high rates of acquired antibiotic resistance in commensal Escherichia coli from healthy children living in urban areas of Bolivia and Peru, including resistance to tetracycline and quinolones, which are not routinely used in childhood. In this work we investigated acquired resistance in commensal E. coli from healthy children and home-raised chickens in 12 households from one of the previously surveyed urban area in Bolivia, to ascertain the possibility of human-animal exchange of resistant strains in similar settings. The resistance rates to ampicillin, tetracycline, chloramphenicol, streptomycin, and trimethoprim-sulphametoxazole were overall high (≥50%) and comparable between children and chickens, whereas those to quinolones were significantly higher in chickens (81% vs. 29% for nalidixic acid; 43% vs. 10% for ciprofloxacin). Molecular characterization of tetracycline- and quinolone-resistant isolates (n = 66) from children and chickens of three selected households revealed a remarkable clonal diversity and, in some cases, the presence of the same resistant strains among children or among chickens living in the same household, but not between children and chickens. Several resistance plasmids were characterized, but inter-clonal plasmid dissemination was not detected. Overall, the results from the present study suggested that cross-transmission between children and home-raised chickens could not represent a major spreading mechanism for resistant E. coli in households of resource-limited settings with high human-animal promiscuity.
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.
Increasing Resistance in CommensalEscherichia coli, Bolivia and Peru
(Centers for Disease Control and Prevention, 2008) Alessandro Bartoloni; Lucia Pallecchi; Costanza Fiorelli; Tiziana Di Maggio; Connie Fernandez; Ana Liz Villagrán; Antonia Mantella; Filippo Bartalesi; Marianne Strohmeyer; Angela Bechini
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Low prevalence of methicillin-resistant Staphylococcus aureus nasal carriage in urban and rural community settings in Bolivia and Peru
(Elsevier BV, 2012) Alessandro Bartoloni; Lucia Pallecchi; Connie Fernandez; Antonia Mantella; Eleonora Riccobono; Donata Magnelli; Dario Mannini; Marianne Strohmeyer; Filippo Bartalesi; Higinio Segundo
This study provides an insight into the epidemiology of MRSA in community settings of Bolivia and Peru. Reliable, time-saving, and low-cost methods should be implemented to encourage continued surveillance of MRSA dissemination in resource-limited countries.
Multidrug-resistant CommensalEscherichia coliin 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.
Population Structure and Resistance Genes in Antibiotic-Resistant Bacteria from a Remote Community with Minimal Antibiotic Exposure
(American Society for Microbiology, 2007) Lucia Pallecchi; Chiara Lucchetti; Alessandro Bartoloni; Filippo Bartalesi; Antonia Mantella; Herlan Gamboa; Alessandra Carattoli; Franco Paradisi; Gian María Rossolini
In a previous study, we detected unexpectedly high levels of acquired antibiotic resistance in commensal Escherichia coli isolates from a remote Guaraní Indian (Bolivia) community with very low levels of antibiotic exposure and limited exchanges with the exterior. Here we analyzed the structure of the resistant E. coli population from that community and the resistance mechanisms. The E. coli population (113 isolates from 72 inhabitants) showed a high degree of genetic heterogeneity, as evidenced by phylogenetic grouping (77% group A, 10% group B1, 8% group D, 5% group B2) and genotyping by randomly amplified polymorphic DNA (RAPD) analysis (44 different RAPD types). The acquired resistance genes were always of the same types as those found in antibiotic-exposed settings [blaTEM, blaPSE-1, catI, cmlA6, tet(A), tet(B), dfrA1, dfrA7, dfrA8, dfrA17, sul1, sul2, aphA1, aadA1, aadA2, aadA5, aadB, and sat-1]. Class 1 and class 2 integrons were found in 12% and 4% of the isolates, respectively, and harbored arrays of gene cassettes similar to those already described. The cotransferability of multiple-resistance traits was observed from selected isolates and was found to be associated with resistance conjugative plasmids of the F, P, and N types. Overall, these data suggest that the resistance observed in this remote community is likely the consequence of the dissemination of resistant bacteria and resistance genes from antibiotic-exposed settings (rather than of an independent in situ selection) which involved both the clonal expansion of resistant strains and the horizontal transfer/recombination of mobile genetic elements harboring resistance genes.
Relentless increase of resistance to fluoroquinolones and expanded-spectrum cephalosporins in Escherichia coli: 20 years of surveillance in resource-limited settings from Latin America
(Elsevier BV, 2012) Alessandro Bartoloni; Lucia Pallecchi; Eleonora Riccobono; Antonia Mantella; Donata Magnelli; T. Di Maggio; A.L. Villagran; Yosleidys Rivero Lara; Carlos Saavedra; M. Strohmeyer