Brânduşa Elena Lixandru

Cantacuzino Institute, Bucureşti, Bucureşti, Romania

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Publications (5)19.57 Total impact

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    ABSTRACT: Although Staphylococcus aureus is frequently reported among the common causative agents of foodborne diseases in Europe, very little is known about the strains involved in staphylococcal food-poisoning outbreaks in our region. Therefore, the aim of this study was to characterize the staphylococcal strains recovered from an autochthonous food-poisoning familial outbreak through phenotypic and genotypic methods. Ten S. aureus strains from food and human sources, submitted to the reference laboratory, were tested for susceptibility to 18 antibiotics by disk diffusion and production of enterotoxins A, B, C, D using a reversed passive latex-agglutination assay, and further analyzed by multiplex PCR-based assays for the detection of sea, seb, sec, sed, see, seh, sei, sej, sem, and sen genes. Phage typing, pulsed-field gel electrophoresis (PFGE) and spa typing were performed for evaluating the clonal relatedness of the isolates. Isolates from stool samples and food displayed a similar antibiotic resistance profile, produced enterotoxin B, were PCR-positive for seb, sei and sem genes, and revealed an indistinguishable SmaI macrorestriction pattern at PFGE analysis, suggesting that incriminated food was most likely the source of this food poisoning outbreak. The isolate which expressed a different antibiotic susceptibility profile and tested negative at the screening for enterotoxin production carried seh gene and was discriminated by a nine-band different PFGE profile from the rest. Combined phenotypic and genotypic profiles by multiple typing are necessary to explore key features of epidemic strains and start to lead to a better understanding of the local epidemiology of infections due to toxigenic S. aureus strains.
    Roumanian archives of microbiology and immunology 05/2014; 72(3):210-7.
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    ABSTRACT: Extended-spectrum-beta-lactamase (ESBL)-producing Escherichia coli (ESBL E. coli) strains are of major concern because few antibiotics remain active against these bacteria. We investigated the association between the fecal relative abundance (RA) of ESBL-producing E. coli (ESBL-RA) and the occurrence of ESBL E. coli urinary tract infections (UTIs). The first stool samples passed after suspicion of UTI from 310 women with subsequently confirmed E. coli UTIs were sampled and tested for ESBL-RA by culture on selective agar. Predictive values of ESBL-RA for ESBL E. coli UTI were analyzed for women who were not exposed to antibiotics when the stool was passed. ESBL E. coli isolates were characterized for ESBL type, phylogroup, relatedness, and virulence factors. The prevalence of ESBL E. coli fecal carriage was 20.3%, with ESBL E. coli UTIs being present in 12.3% of the women. The mean ESBL-RA (95% confidence interval [CI]) was 13-fold higher in women exposed to antibiotics at the time of sampling than in those not exposed (14.3% [range, 5.6% to 36.9%] versus 1.1% [range, 0.32% to 3.6%], respectively; P < 0.001) and 18-fold higher in women with ESBL E. coli UTI than in those with another E. coli UTI (10.0% [range, 0.54% to 100%] versus 0.56% [range, 0.15% to 2.1%[, respectively; P < 0.05). An ESBL-RA of <0.1% was 100% predictive of a non-ESBL E. coli UTI. ESBL type, phylogroup, relatedness, and virulence factors were not found to be associated with ESBL-RA. In conclusion, ESBL-RA was linked to the occurrence of ESBL E. coli UTI in women who were not exposed to antibiotics and who had the same clone of E. coli in urine samples and fecal samples. Especially, a low ESBL-RA appeared to be associated with a low risk of ESBL E. coli infection.
    Antimicrobial Agents and Chemotherapy 09/2013; 57(9). · 4.57 Impact Factor
  • Clinical Microbiology and Infection 05/2011; 17(S4):S206. · 4.58 Impact Factor
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    ABSTRACT: Objective: To characterize Staphylococcus aureus strains circulating in a new-born unit during the summer of 2010, in order to provide information for infection containment. Methods: Identification of strains was done by using conventional methods, authomated VITEK2 system and PCR nuc gene detection. We included nuc gene detection in a triplex in house PCR, together with mecA and luk S/F genes detection. For spa typing we used the SeqNet protocol and the Ridom StaphType software (Ridom GmbH). Pulsed Field Gel Electrophoresis was performed according to the HARMONY protocol (Stephen Murchan et al.) and SCCmec typing according to the PCR multiplex updated method (C. Milheirico et al. − AAC, 2007). Disc diffusion was used for antimicrobial susceptibility testing, according to the EUCAST method. For cefoxitin and vancomycin MIC detection we used the E-test. Results: Bacterial cultures received by our national reference laboratory from a new-born unit were isolated during two summer months, in 2010, from umbilical wounds (nr. = 13), nasal exsudate (nr. = 7), and two other body sites. We identified 22 S. aureus strains, from which 2 MSSA and 20 MRSA. All MRSA belongged to the t127 spa type. The 20 MRSA strains were equally distributted between 2 PFGE patterns, with a Dice index of similarity of 87.5%. All MRSA strains were SCCmec type VI or a type VI variant and PVL negative. The MSSA strains were of spa type t616 and t1556, respectively, showing a low similarity index with the MRSA strains. All MRSA strains, except one, showed the same antimicrobial resistance pattern, with resistance to FOX, E, DA (MLSBi), CN and TE. One strain was aditionally resistant to Ciprofloxacin. Conclusion: Molecular analysis of MRSA strains isolated from a newborn unit revealed a cluster of strongly related strains, supporting the hypothesis that a success clone is evolving in this care unit. Besides local measures, further studies are needed for deeper understanding the origin of the evolving strain.
    Clinical Microbiology and Infection 01/2011; 17(s4):S206. · 4.58 Impact Factor
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    ABSTRACT: Staphylococcus aureus nasal carriage is influenced by multifactorial interactions which are difficult to study in open populations. Therefore, we concomitantly assessed the epidemiological, microbiological, and human-genetic carriage-related factors in a nearly closed population. In 2006 and 2008, we collected nasal S. aureus strains, human DNA, and epidemiological data from 154 adult Wayampi Amerindians living in an isolated village in the Amazonian forest. The genetics of the strains (multilocus sequence type, spa type, and toxin-content type), epidemiological risk factors, antibiotic exposure, and allelic polymorphism of human genes putatively involved in carriage of the persistent carriers were compared with those of other volunteers. Overall carriage prevalence was 41.7% in 2006 and 57.8% in 2008, but the overall prevalence of persistent carriage was only 26%. The rare and phylogenetically distant multilocus sequence type ST1223 was present in 18.5% of the carriers in 2006 and 34.8% in 2008. No epidemiological factors or antibiotic exposure were significantly associated with persistent carriage, but single nucleotide polymorphism distribution in C-reactive proteins C2042T and C1184T and interleukin-4 C524T genes was significantly associated (P=.02, by global test). Host genetic factors appeared to be the predominant determinant for S. aureus persistent nasal carriage in humans.
    The Journal of Infectious Diseases 09/2010; 202(6):924-34. · 5.85 Impact Factor