Supplement 2003-2007 (No. 47) to the White-Kauffmann-Le Minor scheme.

This supplement reports the characterization of 70 new Salmonella serovars recognized between 2003 and 2007 by the WHO Collaborating Center for Reference and Research on Salmonella: 44 were assigned to Salmonella enterica subspecies enterica, 11 to subspecies salamae, 5 to subspecies arizonae, 8 to subspecies diarizonae, one to subspecies houtenae and one to Salmonella bongori. One new serovar, Mygdal, displayed a new H factor, H:z(91).

L-Sorbose utilization by virulent Escherichia coli and Shigella: different metabolic adaptation of pathotypes.

The frequency of L-Sorbose utilization differs significantly between pathotypes of Escherichia coli and Shigella from 93% to 0%. Among 266 strains tested, this frequency increased in the order Shigella, enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), Shiga toxin-producing E. coli (STEC), enteroaggregative E. coli, enteropathogenic E. coli (EPEC), and neonatal bacterial meningitis (NBM) E. coli. This suggests an association of pathomechanism with the capability to degrade L-Sorbose. The use of a selective agar, containing L-Sorbose and antibiotics, facilitated the isolation of L-Sorbose-non-utilizing ETEC from stool specimens of patients. The sor operon, comprising seven genes in the order sorCDFBAME, confers L-Sorbose utilization. Surprisingly, L-Sorbose-non-degrading Shigella harbored all genes of the sor operon indicating L-Sorbose-utilizing E. coli as ancestor. Additionally, strains of several EIEC and STEC serotypes harbored an inactivated sor operon. These L-Sorbose-non-utilizing Shigella, EIEC, and STEC showed significantly reduced amounts of transcripts as examined for sorC and sorD. Common surface antigens, types of intimin gene, and hemolysin gene as well as use of L-Sorbose suggested the relatedness of attaching and effacing O26:H11 and O55:H7 EPEC and STEC, respectively. pepE and yibC genes flank the sor operon of E. coli and Shigella strains. Surprisingly, one O7:K1:H- NBM E. coli harbored an aroE-homologous gene between its sor operon and pepE as in Klebsiella pneumoniae suggesting a horizontal gene transfer. In conclusion, L-Sorbose utilization of virulent E. coli and Shigella is characterized by different adaptation that represents a valuable tool for evolutionary and diagnostic analysis of related patho- and serotypes.

Shiga toxin-producing Escherichia coli infection in Germany: different risk factors for different age groups.

The authors conducted a matched case-control study in Germany to identify risk factors for sporadic illness associated with Shiga toxin-producing Escherichia coli (STEC) infection, regardless of serogroup. From April 2001 through March 2003, cases were prospectively enrolled through a laboratory-based sentinel surveillance system located in 14 of the 16 German federal states. One control was identified per case, matched by age and region. Conditional logistic regression was used in the analysis, which was conducted separately for three age groups (<3 years, 3-9 years, and > or =10 years). The median age of the 202 enrolled cases was 2.5 years (range, 3 months-89 years). Hemolytic uremic syndrome developed in five patients. Non-O157 strains accounted for 85% of the isolated STEC. In children under 3 years of age, having touched a ruminant had the highest odds of disease, and raw milk was the only food identified as a risk factor. In contrast, in persons aged 10 years or older, only food items (i.e., lamb meat, raw spreadable sausages) were significantly associated with illness. In this study, risk factors were age-specific. Direct transmission through food played a lesser role in children under 3 years of age, the population at greatest risk of both acquiring STEC infection and developing hemolytic uremic syndrome.

Salmonella agona outbreak from contaminated aniseed, Germany.

A nationwide outbreak of Salmonella Agona caused by aniseed-containing herbal tea occurred from October 2002 through July 2003 among infants in Germany. Consumers should adhere strictly to brewing instructions, although in exceptional cases this precaution may not be protective, particularly when preparing tea for vulnerable age groups.

Supplement 2002 (no. 46) to the Kauffmann-White scheme.

This supplement reports the characterization of 18 new Salmonella serovars recognized in 2002 by the WHO Collaborating Centre for Reference and Research on Salmonella: 12 were assigned to S. enterica subspecies enterica, 2 to subspecies salamae, 2 to subspecies diarizonae, 1 to subspecies houtenae and 1 to S. bongori.

Supplement 2001 (no. 45) to the Kauffmann-White scheme.

This supplement reports the characterization of 22 new Salmonella serovars recognized in 2001 by the WHO Collaborating Centre for Reference and Research on Salmonella: 14 were assigned to S. enterica subspecies enterica, 2 to subspecies salamae, 1 to subspecies arizonae, 4 to subspecies diarizonae and 1 to subspecies indica.

Comparative and genetic analyses of the putative Vibrio cholerae lipopolysaccharide core oligosaccharide biosynthesis (wav) gene cluster.

We identified five different putative wav gene cluster types, which are responsible for the synthesis of the core oligosaccharide (OS) region of Vibrio cholerae lipopolysaccharide. Preliminary evidence that the genes encoded by this cluster are involved in core OS biosynthesis came from analysis of the recently released O1 El Tor V. cholerae genome sequence and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of O1 El Tor mutant strains defective in three genes (waaF, waaL, and wavB). Investigations of 38 different V. cholerae strains by Southern blotting, PCR, and sequencing analyses showed that the O1 El Tor wav gene cluster type is prevalent among clinical isolates of different serogroups associated with cholera and environmental O1 strains. In contrast, we found differences in the wav gene contents of 19 unrelated non-O1, non-O139 environmental and human isolates not associated with cholera. These strains contained four new wav gene cluster types that differ from each other in distinct gene loci, providing evidence for horizontal transfer of wav genes and for limited structural diversity of the core OS among V. cholerae isolates. Our results show genetic diversity in the core OS biosynthesis gene cluster and predominance of the type 1 wav gene locus in strains associated with clinical cholera, suggesting that a specific core OS structure could contribute to V. cholerae virulence.

Shiga Toxin-Producing Escherichia coli Infections in Germany †.

A prospective study was carried out in collaboration with two children's hospitals in Würzburg, Germany to assess the incidence and clinical manifestations of infections due to Shiga toxin-producing Escherichia coli (STEC) in children. Between 1991 and 1995, stool samples from 2788 children with enteritis were investigated for the occurrence of STEC. STEC cultures from stools were screened using PCR with primers complementary to Shiga toxin 1(Stx1) and Shiga toxin 2 (Stx2) genes. PCR-positive samples were further subjected to colony blot hybridization and probe positive colonies were serotyped and analyzed for the presence of virulence genes. There was an increase in the incidence of STEC infections from 0.4% in 1991 to 2.8% in 1994. In 1995 the number of infections remained nearly unchanged (2.5%). Infection with STEC was associated with painful nonbloody diarrhea in most patients. Among the 35 patients in this study with stools containing STEC, only 9 (25.7%) had O157 colonies of which 3 (8.6%) were O157:H7 and 6 (17.1%) were sorbitol-fermenting O157:H-. In an additional study in 1994/l995, STEC etiology in 88 patients with HUS from Germany was confirmed in our laboratories by culture of STEC from stools, and in 20 additional HUS cases by serological analysis. Of the strains from stools of HUS patients, 78% belonged to serogroup O157. The most frequently isolated non-O157 serogroups were O26 and O111. These results demonstrate that when analyzing stools of patients with bloody diarrhea, HUS, or painful nonbloody diarrhea, the occurrence of non-O157:H7 strains should be considered when classical microbiological analysis fails to yield a standard enteric pathogen, such as Campylobacter . E. coli O157:H7, Salmonella . Shigella , or Yersinia .