Publications (2)6.69 Total impact
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Article: VanA-type enterococci from humans, animals, and food: species distribution, population structure, Tn1546 typing and location, and virulence determinants.
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ABSTRACT: VanA-type human (n=69), animal (n=49), and food (n=36) glycopeptide-resistant enterococci (GRE) from different geographic areas were investigated to study their possible reservoirs and transmission routes. Pulsed-field gel electrophoresis (PFGE) revealed two small genetically related clusters, M39 (n=4) and M49 (n=13), representing Enterococcus faecium isolates from animal and human feces and from clinical and fecal human samples. Multilocus sequence typing showed that both belonged to the epidemic lineage of CC17. purK allele analysis of 28 selected isolates revealed that type 1 was prevalent in human strains (8/11) and types 6 and 3 (14/15) were prevalent in poultry (animals and meat). One hundred and five of the 154 VanA GRE isolates, encompassing different species, origins, and PFGE types, were examined for Tn1546 type and location (plasmid or chromosome) and the incidence of virulence determinants. Hybridization of S1- and I-CeuI-digested total DNA revealed a plasmid location in 98% of the isolates. Human intestinal and animal E. faecium isolates bore large (>150 kb) vanA plasmids. Results of PCR-restriction fragment length polymorphism and sequencing showed the presence of prototype Tn1546 in 80% of strains and the G-to-T mutation at position 8234 in three human intestinal and two pork E. faecium isolates. There were no significant associations (P>0.5) between Tn1546 type and GRE source or enterococcal species. Virulence determinants were detected in all reservoirs but were significantly more frequent (P<0.02) among clinical strains. Multiple determinants were found in clinical and meat Enterococcus faecalis isolates. The presence of indistinguishable vanA elements (mostly plasmid borne) and virulence determinants in different species and PFGE-diverse populations in the presence of host-specific purK housekeeping genes suggested that all GRE might be potential reservoirs of resistance determinants and virulence traits transferable to human-adapted clusters.Applied and Environmental Microbiology 05/2007; 73(10):3307-19. · 3.83 Impact Factor -
Article: Recovery from a single blood culture of two enterococcus gallinarum isolates carrying both vanC-1 and vanA cluster genes and differing in glycopeptide susceptibility.
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ABSTRACT: Two Enterococcus gallinarum isolates distinguished by different colony sizes were recovered from the same blood culture from a woman with acute myeloid leukemia. They were designated E31 (the one with larger colonies) and E32 (the one with smaller colonies). Both isolates were glycopeptide resistant, but the MICs of vancomycin and teicoplanin for E31 (32 and 2 microg/ml, respectively, consistent with the VanC phenotype) and E32 (128 and 16 microg/ml, respectively, consistent with the VanA phenotype) were different. E31 and E32 had the same plasmid profile and showed identical pulsed-field gel electrophoresis patterns after digestion of total DNA with NotI and a two-band variation after digestion with SmaI. Polymerase chain reaction experiments showed that both isolates had both the vanC-1 and vanA genes and carried a Tn1546-related transposon lacking orf1, vanY, and vanZ. The absence of these three genes was confirmed by Southern analysis with appropriate probes. Southern hybridization experiments using a vanA probe showed that this atypical Tn1546-related element appeared to be located on the chromosome. In both E31 and E32, the vanA probe hybridized to EcoRV and HindIII fragments larger in size than the hybridizing fragments observed in the VanA prototype strain Enterococcus faecium BM4147, suggesting the lack of the relevant EcoRV and HindIII restriction sites.European Journal of Clinical Microbiology 06/2001; 20(5):309-14. · 2.86 Impact Factor
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Institutions
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2007
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Istituto Superiore di Sanità
- Department of Technology and Health
Roma, Latium, Italy
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