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ABSTRACTIn May 2000, the first outbreak of vancomycin-resistant Enterococcus faecium(VREF) was detected in the University Medical Center Utrecht in the nephrology ward. The question arose why some VREF strains spread among hospitalized patients, whereas other strains do not. Thirty patients who were found to be colonized with VREF between May and November 2000 were included in the study. Molecular typing confirmed that 19 of them carried an identical epidemic strain which harbored the espgene while 11 were colonized by nonepidemic strains that were all espnegative. Acquisition of the outbreak strain was significantly associated with diabetes mellitus, renal transplantation, and extensive use of antibiotics, especially cephalosporins, in the 2-month period before the first isolation of VREF. To establish the duration of colonization, prospective surveillance of VREF carriage for a 6-month period starting from the first isolation of VREF was realized for 20 patients. After 6 months, VREF was still recovered from 60% of carriers of the outbreak strain versus 20% of carriers of nonepidemic strains (P< 0.01). However, antibiotic use during the follow-up period was significantly higher by carriers of the outbreak strain than by carriers of nonepidemic strains. The fact that the outbreak strain was recovered for a longer period of time than nonepidemic strains may facilitate dissemination of the strain. The results support a careful restrictive antibiotic policy for wards at risk for spread of VREF and implementation of isolation precautions for patients who are colonized with esp-positive outbreak strains.

Since the mid1980s, there have been increasing numbers of reports on the resurgence of severe invasive group A streptococcal infections worldwide. Despite prompt therapy with penicillin andor clindamycin, the mortality rates of these infections, including streptococcal toxic shocklike syndrome, remain high. Among the many virulence factors pyrogenic exotoxins A SPEA and B SPEB, associated with certain virulent serotypes including M1 and M3 strains, have been implicated in the pathogenesis of serious streptococcal manifestations. The biological effects of SPEA and SPEBin vitroas well asin vivoare summarised and the implications for the pathogenesis and treatment of invasive group A streptococcal diseases are discussed.

In this pilot study, we investigated the relative avidities for streptococcal pyrogenic exotoxin A (SPE-A) and SPE-B of antibodies in sera from patients with fatal streptococcal toxic shock-like syndrome and from healthy individuals and in intravenous immunoglobulin (IVIG) preparations. We observed a great variation in the relative avidities of patient, control, and IVIG immunoglobulin G (IgG) (values estimated to be between 10(-7) and 10(-11) M), with mean values for patient IgG about 10-fold lower than those of control IgG.

An important role in the pathogenesis of invasive group A streptococcal disease has been ascribed to the production of streptococcal pyrogenic exotoxin A. We present a new technique for the purification of streptococcal pyrogenic exotoxin A from Streptococcus pyogenes NY-5 supernate, which is highly efficient with respect to yield (35%), purity (> or = 99%), and time.