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Background: A retrospective study of the clinical, epidemiologic, and virologic features of norovirus gastroenteritis in 12 adult allogeneic hematopoietic stem cell transplant (HSCT) recipients., Methods: Norovirus infection was diagnosed by reverse-transcriptase polymerase chain reaction. Strains were genotyped by nucleic acid sequence of the most highly conserved region of the norovirus gene encoding the capsid S (shell) domain., Results: Ten of 12 patients presented with vomiting of short duration, but diarrhea was present in all. The median time from onset to norovirus diagnosis was 1 month (range, 0.25-6.0 months). Eleven patients were receiving immunosuppression when norovirus infection was diagnosed: 8 for graft-versus-host disease (GVHD) in an organ other than gut, 1 for previous gut GVHD, and 2 for presumed gut GVHD that proved to be norovirus gastroenteritis. Six patients required enteral or parenteral nutrition for severe weight loss. In 10 patients, diarrhea lasted a median of 3 months (range, 0.5-14 months) and virus was shed at a high level throughout. The remaining 2 patients died after 4 months of diarrhea (one died of unrelated complications, and the other died of malnutrition). The noroviruses found were GII (untyped), GII-3, GII-4, and GII-7 in 1, 1, 9, and 1 patients, respectively. Eleven of the 12 patients had acquired their infection in the community. Phylogenetic analysis of the GII-4 strains demonstrated that all differed., Conclusions: Noroviruses are a hitherto unsuspected cause of prolonged morbidity and mortality in adults after allogeneic HSCT. The use of reverse-transcriptase polymerase chain reaction to detect high viral load levels in feces distinguishes norovirus gastroenteritis from gut GVHD.

Objective: Surveillance data on Helicobacter pylori antibiotic susceptibilities in Wales are limited, despite resistance being a key factor in treatment failure. A single-centre survey was undertaken over 3 years to determine local antibiotic resistance rates on isolates from dyspeptic patients in Bangor, Gwynedd (North Wales)., Methods: Susceptibilities were determined for 363 isolates by disc diffusion and the Etest. Isolates were also genotyped (cagA presence and vacA allelic types)., Results: Overall in vitro resistance rates were 24% for metronidazole and 7% for clarithromycin, with 4% resistant to both antibiotics. Resistant strains typically had high MICs of >256 mg/L. Tetracycline resistance was identified in only one isolate whereas no isolates showed resistance to amoxicillin. There was a two-fold increase in resistance over the study period. No gender and age associations with resistance were detected. Resistant and susceptible isolates were genotypically diverse with respect to cagA/vacA type but the vacA s1m2 form was a feature of all clarithromycin-resistant isolates compared with 56% of the susceptible isolates., Conclusion: Although the overall antibiotic resistance rates of H. pylori from North Wales were low compared with many other regions in Europe, continued surveillance, particularly of high-level resistance (MIC >256 mg/L), is recommended to monitor the effects of the 'test and treat' strategy for H. pylori eradication.

Helicobacter pullorum was first isolated from the faeces and carcasses of poultry and has been associated with human gastroenteritis. The aim of this study was to examine interstrain genetic diversity within H. pullorum. Two fingerprinting techniques were used: amplified fragment length polymorphism (AFLP) and pulsed field gel electrophoretic (PFGE) analysis. The 20 strains examined were from four countries and comprised 13 human isolates and seven poultry isolates. Their identity was confirmed by a species-specific PCR assay. The human and poultry isolates had distinct genotypes and most strains showed a high degree of genetic diversity. Genotyping also indicated a clonal origin for two strains from the same poultry flock, and established a close relatedness between three chicken carcass isolates from a processing plant. It is concluded that these two genotyping techniques will provide a useful basis for future epidemiological investigations of H. pullorum in poultry, and may provide a link with its possible causal role in human gastrointestinal infections.

Streptococcus pyogenes strains were genotyped by a combination of molecular methods for high- resolution epidemiologic studies of disease outbreaks. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the emm gene is reported. Alone or in conjunction with other molecular techniques (16S ribotyping, pulsed-field gel electrophoresis, and detection of exotoxin genes), PCR-RFLP could differentiate outbreak-related strains from contemporaneous background strains of the same M serotype. Three outbreaks were studied: pharyngitis in a boarding school (serotype M5), cross-infection in a hospital burn unit (serotype M76), and severe invasive disease in two elderly care homes (serotype R28). It was possible, for example, to identify within serotype R28 a clone with particular potential for invasive disease. In all cases, the four molecular methods yielded complementary results that were hierarchically related. Strains could be assigned to the outbreak or the background in a precise, reproducible, and rapid manner.