Jørgen Lassen

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BACKGROUND On 20-21 February 2006, six cases of diarrhoea-associated haemolytic uraemic syndrome (HUS) were reported by paediatricians to the Norwegian Institute of Public Health. We initiated an investigation to identify the etiologic agent and determine the source of the outbreak in order to implement control measures. METHODS A case was defined as a(More)
In 1989 and 1990, a case-control study designed to identify risk factors for sporadic infections with thermotolerant Campylobacter bacteria was conducted in three counties in southeastern Norway. The investigation was confined to infections which were acquired in Norway. A total of 52 bacteriologically confirmed cases and 103 controls matched by age, sex,(More)
On November 15, 2004, a cluster of three cases of Salmonella Thompson infection was registered by the Norwegian reference laboratory. In the following days further cases occurred, prompting a case-control study among the first 13 cases and 26 matched controls. By December 31, 21 cases had been reported, with the first onset on October 24. Consumption of(More)
We report the emergence of Salmonella enterica isolates of serotype Concord (and its monophasic variant 6,7:l,v:-) producing the extended-spectrum beta-lactamases (ESBLs) SHV-12 and CTX-M-15 in France and Norway between 2001 and 2006 (43 in France and 26 in Norway). The majority of these isolates were from adopted children from Ethiopia, most of whom were(More)
In July 2001, the Norwegian Institute of Public Health (Folkehelseinstituttet, FHI) reported a cluster of Salmonella Enteritidis of phage type 14b infections in Norwegian travellers returning from Greece. An increase in the same uncommon phage type was also registered in Sweden and Finland at the same time. Cases of S. Enteritidis PT 14b in patients(More)
A multiplex PCR assay, amplifying seven specific virulence genes and one internal control gene in a single reaction, was developed to identify the five main pathotypes of diarrheagenic Escherichia coli and Shigella spp. The virulence genes selected for each category were Stx1, Stx2, and eaeA for enterohemorrhagic E. coli (EHEC), eaeA for enteropathogenic E.(More)
In 1987, a nationwide outbreak of Salmonella typhimurium O:4-12 infection traced to contaminated chocolate bars occurred in Norway. In the 5 years after the outbreak, elevated numbers of sporadic cases caused by the epidemic strain of Salmonella were detected, followed by a decline in subsequent years. To characterize the epidemiology of this infection, the(More)
The antimicrobial resistance of 809 Salmonella Typhimurium isolates collected from humans in Norway between 1975 and 1998 was studied. The material was subdivided into domestic and foreign isolates according to whether the patient had recently travelled abroad or not. In imported isolates the largest increase in resistance was in 1996 when 35% of the(More)
Biochemical and genetic identification by RFLP (restriction fragment length polymorphism) of the PCR-amplified 16S r-RNA sequence were compared for a selection of 171 clinical and environmental isolates of Aeromonas spp. The investigation revealed large differences between the two methods. The species phenotypic identification scheme and the genetic(More)