9 research outputs found
VanA type enterococci from humans, animals and food: species distribution, population structure, Tn1546-typing and location, and virulence determinants
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
Detection of viable but non-culturable staphylococci in biofilms from central venous catheters negative on standard microbiological assays
none7To our knowledge this is the first evidence that S. epidermidis
and S. aureus can enter the VBNC state. If positively
documented, their ability to persist in this state could help to
explain the well-known prevalence of both species in recurrent
CVC-related infections [4,8,17,18]. Detection of S. epidermidis in 62% of CVCs demonstrated to contain non-culturable bacteria (removed from febrile patients, 27% of whom also had a positive blood culture) supports this hypothesis. Further research into the relationship among VBNC forms found in CVC-associated biofilms, their actual metabolic activity and recurrent infection, as well as careful recording of concurrent clinical data, are required to gain insights into the possible role of VBNC bacterial cells in indwelling medical device-related persistent infections.G. Zandri;S. Pasquaroli;C. Vignaroli;S. Talevi;E. Manso;G. Donelli;F. BiavascoG., Zandri; Pasquaroli, Sonia; Vignaroli, Carla; S., Talevi; E., Manso; G., Donelli; Biavasco, Francesc
Valutazione della presenza di forme batteriche vitali ma non coltivabili (VBNC) di stafilococco presenti in biofilm associati a cateteri venosi centrali (CVC).
VanA-Type Enterococci from Humans, Animals, and Food: Species Distribution, Population Structure, Tn1546 Typing and Location, and Virulence Determinants▿
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