Defining a sapovirus outbreak in this study as >1 sapovirus-positive fecal sample, 21 (23%) of the 93 norovirus-negative outbreaks were found to be caused by sapovirus.
First, testing a convenience sample of fecal specimens from norovirus-negative outbreaks might have introduced selection bias, the impact of which is uncertain.
The Minnesota Public Health Laboratory tested feces from 93 (66%) of the 142 norovirus-negative outbreaks with RT-PCRs for astrovirus, adenovirus, rotavirus, norovirus, and sapovirus (6 ).
Widdowson et al [ 18] found that 25% of bacteria-negative outbreaks were not analyzed to detect viral causes, but this type of information is not normally available.
In keeping with recent recommendations, at minimum, adding sapovirus to routine diagnostics of infections that occur in any setting and by any mode of transmission will establish etiologies of some norovirus-negative outbreaks and help define the disease impact and clinical characteristics of sapovirus infections (9, 10, 13 ).
We tested fecal samples from 93 norovirus-negative gastroenteritis outbreaks; 21 outbreaks were caused by sapovirus.
Nevertheless, if compared to other gram-negative bacteria, outbreaks by P. aeruginosa in NICU settings have been much less reported up-to-date and have been associated with both environmental reservoirs and healthcare workers' carriage [ 7- 10].
Briese et al. (1 ) are to be congratulated for their delineation of the global geographic presence of human rhinovirus (HRV) strains similar to those reported in 2006 from one third of cases of an otherwise pathogen-negative respiratory outbreak in New York.
Phosphatase tests on pasteurized milk and cheese products were also negative in both outbreaks (Table 2).
The presence of phenolic content confers O. europaea L. natural resistance to microbe (Gram negative, Gram positive) outbreak [32].
