A multiplex PCR for the simultaneous detection of five virulence genes (asa1, gelE, cylA, esp, and hyl) in enterococci was developed. The presence of these genes was investigated in 153 clinical and 118 fecal Enterococcus faecium isolates from inpatients at an increased risk of developing infections (such as patients in intensive care units and hematology wards) from 13 hospitals in eight European countries. Of the 271 E. faecium isolates, 135 were vancomycin resistant E. faecium (VREF) isolates and 136 were vancomycin susceptible E. faecium (VSEF) isolates. Susceptibilities to ampicillin, gentamicin, streptomycin, vancomycin, teicoplanin, ramoplanin, quinupristin-dalfopristin, and linezolid were tested by the microdilution method. Overall, the prevalence of esp was significantly higher (P ‫؍‬ 0.03) in clinical VREF isolates (92%) than in fecal VREF isolates (73%). In Italy, the prevalence of esp was significantly higher (P ‫؍‬ 0.02) in VREF isolates (91%) than in VSEF isolates (68%), whereas in the United Kingdom, hyl was significantly more prevalent (P ‫؍‬ 0.01) in VREF isolates (71%) than in VSEF isolates (29%). No significant differences were found for the other countries. Pulsed-field gel electrophoresis was used to check the clonality among the strains tested and showed the spread of two center-specific (esp-positive) VREF clones in Italy and one center-specific (hyl-positive) clone in the United Kingdom. These clones were resistant to ampicillin, gentamicin, and streptomycin. The multiplex PCR reported in this study is a convenient and rapid method for the simultaneous detection of the virulence genes asa1, gelE, cylA, esp, and hyl in enterococci. Molecular analysis showed the intrahospital spread of esp-positive VREF clones (in Italy) and hyl-positive VREF clones (in the United Kingdom); the role of hyl remains to be elucidated.Enterococci form part of the normal flora of both the human and the animal gastrointestinal tract. However, vancomycinresistant enterococci have emerged as a major cause of nosocomial infections (28). Several virulence factors have been described in enterococci, for instance, aggregation substance (14), gelatinase (39), cytolysin (4), enterococcal surface protein (38), and, very recently, hyaluronidase (35). The first four virulence factors are found in Enterococcus faecalis, while the fourth and fifth virulence factors are specific for Enterococcus faecium.

Platelets migrate extravascularly in response to a sensitizing allergen via a mechanism dependent on the interaction among allergen, allergen-specific IgE, and the FcepsilonRI, and this may allow them to participate directly in allergic tissue inflammation.

No abstract

Glycopeptide resistance has been studied in detail in enterococci and staphylococci. In these microorganisms, high-level resistance is achieved by replacing the C-terminal D-alanyl-D-alanine of the nascent peptidoglycan with D-alanyl-D-lactate or D-alanyl-D-serine, thus reducing the affinities of glycopeptides for cell wall targets. Reorganization of the cell wall is directed by the expression of the van gene clusters. The identification of van gene homologs in the genomes of several glycopeptide-producing actinomycetes suggests the involvement of a similar self-resistance mechanism to avoid suicide. This report describes a comprehensive study of self-resistance in Actinoplanes teichomyceticus ATCC 31121, the producer of the clinically relevant glycopeptide teicoplanin. A. teichomyceticus ATCC 31121 showed a MIC of teicoplanin of 25 g/ml and a MIC of vancomycin of 90 g/ml during vegetative growth. The vanH, vanA, and vanX genes of A. teichomyceticus were found to be organized in an operon whose transcription was constitutive. Analysis of the UDP-linked peptidoglycan precursors revealed the presence of UDP-glycomuramyl pentadepsipeptide terminating in D-alanyl-D-lactate. No trace of precursors ending in D-alanyl-D-alanine was detected. Thus, the van gene complex was transcribed and expressed in the genetic background of A. teichomyceticus and conferred resistance to vancomycin and teicoplanin through the modification of cell wall biosynthesis. During teicoplanin production (maximum productivity, 70 to 80 g/ml), the MIC of teicoplanin remained in the range of 25 to 35 g/ml. Teicoplanin-producing cells were found to be tolerant to high concentrations of exogenously added glycopeptides, which were not bactericidal even at 5,000 g/ml.Glycopeptide antibiotics are produced by actinomycetes and inhibit the synthesis of bacterial cell wall by blocking peptidoglycan assembly. They bind to the D-alanyl-D-alanine (DAla-D-Ala) C terminus of the nascent peptidoglycan and prevent it from being utilized in the following cross-linking reactions catalyzed by transglycosylases and transpeptidases (18,38,44). The structurally related glycopeptides vancomycin and teicoplanin have been used in clinical settings since 1958 and 1988, respectively. These drugs are still extensively used against multiresistant enterococci and methicillin-resistant staphylococci. Concern about vancomycin-resistant enterococci has been increasing during the last decade, and highly vancomycin resistant Staphylococcus aureus isolates have recently appeared in clinical specimens (10, 11).Two resistance phenotypes, VanA and VanB, have been extensively studied in enterococci and are considered of main importance, since the genes responsible for resistance (van genes) are inducible and transferable and confer high-level resistance to vancomycin (at concentrations up to 1,000 g/ml or more) (42). The vanA gene cluster also confers high-level resistance to teicoplanin (4,9,15,16) (16,45,51). The genes vanH, vanA/vanB, and vanX are organized in a cluster and are oft...

We evaluated a number of terthiophenes and polyynes, from the Asteraceae, for biological activities against microorganisms, viruses, and tumor cells, with and without the aid of UVA (long wavelength ultraviolet) radiation. The terthiophenes, which represented the basic alpha-terthienyl nucleus with simple side chains, showed impressive UVA-dependent activities, some of which were superior to alpha-terthienyl itself. In contrast, the polyynes had no significant biological activity, with or without UVA. We believe that these terthiophenes would be worthwhile evaluating in animal models of infectious diseases.