RT-PCR identification and typing of astroviruses and Norwalk-like viruses in hospitalized patients with gastroenteritis:: evidence of nosocomial infections

Background: Astroviruses (HAstVs) and "Norwalk-like viruses" (NLV) are frequent causes of gastroenteritis worldwide, though no data on the strains in circulation or their prevalence is available for France. Objectives: We applied molecular methods to detect HAstVs and NLVs by reverse transcription-polymerase chain reaction (RT-PCR) in fecal samples collected during a 2-year period from children and adults hospitalized with gastroenteritis. Study design: All samples negative for rotavirus and adenovirus by latex agglutination which contained small (25-40 nm) viral particles observed by electron microscopy (EM) were examined by RT-PCR. RT-PCR products were sequenced to characterize the HAstVs and NLV strains present. Results: A total of 75 samples were analyzed by RT-PCR, of which 15 were positive for HAstV and 24 for NLV. Several distinct strains of serotype 1 HAstV, the predominant serotype, circulated during the period. Nineteen of the 24 NLVs were of the G2 genogroup including Mexico-like (n = 10), Bristol-like (n = 8), and Hawaii-like viruses (n = 1); two were genogroup 1. Overall, seven (47%) of the 15 HAstV infections and nine (37.5%) of the 24 NLV infections appeared to be nosocomially acquired based on the date of admission in hospital and the date of illness. Conclusion: This study provides additional evidence of the importance of nosocomial infections caused by NLV and HAstV. (C) 2000 Published by Elsevier Science B.V.