Claudia Barberis

University of Buenos Aires, Buenos Aires, Buenos Aires F.D., Argentina

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Publications (7)15.16 Total impact

  • Article: Impact of heteroresistance to colistin in meningitis caused by Acinetobacter baumannii.
    The Journal of infection 10/2011; 64(1):119-21. · 4.13 Impact Factor
  • Article: Novel gastric helicobacters and oral campylobacters are present in captive and wild cetaceans.
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    ABSTRACT: The mammalian gastric and oral mucosa may be colonized by mixed Helicobacter and Campylobacter species, respectively, in individual animals. To better characterize the presence and distribution of Helicobacter and Campylobacter among marine mammals, we used PCR and 16S rDNA sequence analysis to examine gastric and oral samples from ten dolphins (Tursiops gephyreus), one killer whale (Orcinus orca), one false killer whale (Pseudorca crassidens), and three wild La Plata river dolphins (Pontoporia blainvillei). Helicobacter spp. DNA was widely distributed in gastric and oral samples from both captive and wild cetaceans. Phylogenetic analysis demonstrated two Helicobacter sequence clusters, one closely related to H. cetorum, a species isolated from dolphins and whales in North America. The second related cluster was to sequences obtained from dolphins in Australia and to gastric non-H. pylori helicobacters, and may represent a novel taxonomic group. Dental plaque sequences from four dolphins formed a third cluster within the Campylobacter genus that likely represents a novel species isolated from marine mammals. Identification of identical Helicobacter spp. DNA sequences from dental plaque, saliva and gastric fluids from the same hosts, suggests that the oral cavity may be involved in transmission. These results demonstrate that Helicobacter and Campylobacter species are commonly distributed in marine mammals, and identify taxonomic clusters that may represent novel species.
    Veterinary Microbiology 04/2011; 152(1-2):138-45. · 3.33 Impact Factor
  • Article: [A case of melioidosis in Argentina].
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    ABSTRACT: We describe a case of 17-year- old man native of Dominican Republic, with Hodgkin's lymphoma, who presented soft espontaneous draining nodules. In the clinical samples grew Burkholderia pseudomallei; the etiological agent of melioidosis. He received antimicrobial treatment with imipenem and amoxicillin/clavulanic with very good clinical evolution of the infectious process. Melioidosis diagnosis could be underestimated due to the low incidence of Burkholderia pseudomallei in our continent. The definitive diagnosis depends of the isolation and identification in the clinical sample.
    Medicina 01/2011; 71(1):39-41. · 0.47 Impact Factor
  • Article: Capsule expression and genotypic differences among Staphylococcus aureus isolates from patients with chronic or acute osteomyelitis.
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    ABSTRACT: There is ample evidence that Staphylococcus aureus capsular polysaccharide (CP) promotes virulence. Loss of capsule expression, however, may lead to S. aureus persistence in a chronically infected host. This study was conducted to determine the relative prevalence of nonencapsulated S. aureus in patients with chronic and acute osteomyelitis. Only 76/118 (64%) S. aureus isolates from patients with osteomyelitis expressed CP, whereas all 50 isolates from blood cultures of patients with infections other than osteoarticular infections expressed CP (P = 0.0001). A significantly higher prevalence of nonencapsulated S. aureus was found in patients with chronic osteomyelitis (53%) than in those with acute osteomyelitis (21%) (P = 0.0046). S. aureus isolates obtained from multiple specimens from five of six patients with chronic osteomyelitis exhibited phenotypic (expression of CP, alpha-hemolysin, beta-hemolysin, slime, and the small-colony variant phenotype) and/or genotypic (pulsed-field gel electrophoresis and spa typing) differences. Nonencapsulated S. aureus was recovered from at least one specimen from each chronic osteomyelitis patient. Fourteen isolates obtained from two patients with acute osteomyelitis were indistinguishable from each other within each group, and all produced CP5. In conclusion, we demonstrated that nonencapsulated S. aureus is more frequently isolated from patients with chronic osteomyelitis than from those with acute osteomyelitis, suggesting that loss of CP expression may be advantageous to S. aureus during chronic infection. Our findings on multiple S. aureus isolates from individual patients allow us to suggest that selection of nonencapsulated S. aureus is likely to have occurred in the patient during long-term bone infection.
    Infection and immunity 04/2009; 77(5):1968-75. · 4.21 Impact Factor
  • Article: Antimicrobial susceptibility of non-enterococcal intrinsic glycopeptide-resistant Gram-positive organisms.
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    ABSTRACT: Non-enterococcal Gram-positive bacteria that are intrinsically vancomycin-resistant have been infrequently isolated in association with serious infections. However, well-documented infections have lately been reported with increasing frequency. Because these organisms may be pathogens, we tested the MICs of 19 antimicrobial agents by the agar dilution method for predicting susceptibility. The activity of these antimicrobial agents was assessed against 28 strains (Lactobacillus rhamnosus, 6; Lactobacillus acidophilus, 1; Lactobacillus casei, 1; Lactobacillus fermentum, 2; Lactobacillus brevis, 1; Lactobacillus plantarum, 1; Weissella confusa, 2; Leuconostoc mesenteroides, 7; Leuconostoc lactis, 4; Pediococcus acidilactici, 2; Pediococcus pentosaceus, 1), isolated from clinical specimens in an Argentinian university hospital from 1997 to 2003. The MICs of penicillin for 67% of the Lactobacillus strains and 100% of the Leuconostoc spp. and Pediococcus spp. strains tested were in the 0.25-2 microg/mL range. Erythromycin was the most active antimicrobial overall. Multiresistance was observed in 2 strains (Lactobacillus rhamnosus, 1; Lactobacillus plantarum, 1).
    Diagnostic Microbiology and Infectious Disease 03/2007; 57(2):183-8. · 2.53 Impact Factor
  • Article: [Validation of a rapid urease test for the diagnosis of Helicobacter pylori infection].
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    ABSTRACT: Several non-commercial rapid urease tests have been designed with the objective of reducing the cost of Helicobacter Pylori infection diagnosis. The objective of the present prospective trial is to assess one of these tests, using the histologic evaluation for the presence of Helicobacter Pylori, as the standard reference of diagnosing this infection. Patients undergoing upper endoscopy for various reasons were prospectively enrolled. Three endoscopic biopsies of the antrum and three from the corpus of the stomach were taken in every patient enrolled. The specimens were evaluated by the rapid urease test on an individual basis, comparing the results with the histology assessment of the Helicobacter Pylori status, which was considered as the standard reference for the diagnosis of the infection. One hundred and four patients were enrolled, of which 94 were eligible. Fifty-five patients (60.43%) were infected with Helicobacter Pylori. The sensibility and specificity of the urease test evaluated at 4 hours was 65.45% and 100% respectively. The evaluation at 24 hours of the sensibility and specificity was 83% and 94% respectively. The non-commercial rapid urease test is a practical, fast, and cost effective method for the detection of Helicobacter Pylori infection, and its diagnostic utility is similar to the commercial test available.
    Acta gastroenterologica Latinoamericana 06/2002; 32(1):29-34.
  • Article: [Resistance to extended-spectrum cephalosporins in non-inducible AmpC enterobacteria: evaluation of the new MIC breakpoints].
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    ABSTRACT: The aims of this study were to evaluate the in vitro activity of extended-spectrum cephalosporins (ESC) in non-inducible AmpC enterobacteria throµgh phenotypic and genotypic characterization of the mechanisms of resistance (ESBL, plasmid-mediated AmpC and KPC) and to evaluate the interpretation criteria proposed by the existing recommendations and the new breakpoints established by the CLSI and the EUCAST. Susceptibility tests and PCR multiplex for b/aSHV and b/aCTX-M and amplification using specific primers was performed. One hundred sixty nine resistant isolates: K/ebsie//a pneumoniae (95), Escherichia co/i (55), and Proteus mirabi/is (19) were recovered. ESC resistance was 56.2 %, 32.6%, and 11.2 %, respectively. ESBL was detected in 152 (90 %) isolates, plasmid-mediated AmpC in 12 (7 %) and KPC in 5 (3 %). The CLSI 2009 recommendations and the breakpoints sµggested by the CLSI 2010 and the EUCAST for ceftriaxone were efficacious to detect ESBL, whereas the different breakpoints for ceftazidime presented discrepancies. The CLSI 2010 breakpoints only detected 55 % of the ESBL-producing isolates due to the endemic presence of CTX-M ESBLs in our country. Regarding the plasmid-mediated AmpC producers, the recommendations of the CLSI 2010 and the EUCAST 2010 proved to be more efficient than the old ones.
    Revista Argentina de microbiología 44(1):30-5. · 0.50 Impact Factor