Norovirus GII.4 Detection in Environmental Samples from Patient Rooms during Nosocomial Outbreaks

Abstract

c Norovirus (NoV) is an important cause of nosocomial gastroenteric outbreaks. This 5-month study was designed to characterize NoV contamination and airborne dispersal in patient rooms during hospital outbreaks. Air vents, overbed tables, washbasins, dust, and virus traps designed to collect charged particles from the air were swabbed to investigate the possibility of NoV contamination in patient rooms during outbreaks in seven wards and in an outbreak-free ward. Symptomatic inpatients were also sampled. Nucleic acid extracts of the samples were examined for NoV RNA using genogroup I (GI) and GII real-time reverse transcription-PCR (RT-PCR). The NoV strains were characterized by RT-PCR, sequencing, and phylogenetic analysis of the RNA-dependent RNA-polymerase-N/S capsid-coding region (1,040 nucleotides [nt]). Patient strains from two outbreaks in one ward were sequenced across the RNA-dependent-RNA-polymerase major capsid-coding region (2.5 kb), including the hypervariable P2 domain. In the outbreak wards, NoV GII was detected in 48 of 101 (47%) environmental swabs and 63 of 108 patients (58%); NoV genotype II.4 was sequenced from 18 environmental samples, dust (n ‫؍‬ 8), virus traps (n ‫؍‬ 4), surfaces (n ‫؍‬ 6), and 56 patients. In contrast, NoV GII was detected in 2 (GII.4) of 28 (7%) environmental samples and in 2 (GII.6 and GII.4) of 17 patients in the outbreak-free ward. Sequence analyses revealed a high degree of similarity (>99.5%, 1,040 nt) between NoV GII.4 environmental and patient strains from a given ward at a given time. The strains clustered on 11 subbranches of the phylogenetic tree, with strong correlations to time and place. The high nucleotide similarity between the NoV GII.4 strains from patients and their hospital room environment provided molecular evidence of GII.4 dispersal in the air and dust; therefore, interventional cleaning studies are justified.

Contamination of healthcare workers' mobile phones by epidemic viruses

“…However, epidemic viruses such as influenza viruses, rotavirus (RV) and norovirus (NV) have been shown to be able to adhere and contaminate inert surfaces as well as medical devices close to the patients' environment [10][11][12]. NV and RV were shown to be particularly resistant; they can survive for weeks, even months, on surfaces and in the hospital environment [11,[13][14][15][16]. Contamination of hospital surfaces by these viruses may therefore play a role in nosocomial epidemics [11,13].…”

Burden of norovirus in healthcare facilities and strategies for outbreak control

“…16,19–22 A study of environmental samples from outbreak-affected hospital wards found GII norovirus on almost half of the swabs, including in dust and on surfaces. 23 Once the virus is ingested, there is an incubation period of between 12 and 48 h, after which infected persons generally experience acute onset of symptoms of gastroenteritis, such as vomiting, diarrhoea, abdominal cramps, as well as systemic symptoms, including fever. However, 20–30% of infected individuals may remain asymptomatic.…”

Generic aspects of the airborne spread of human pathogens indoors and emerging air decontamination technologies

“…Indoor air, in particular, can expose us to noxious chemicals, particulates, and a variety of infectious agents, as well as pollen and other allergens. 4,5 Emerging pathogens, such as noroviruses 6 and Clostridium difficile, 7 have also been detected in indoor air, with a strong potential for airborne dissemination. Pathogens discharged into the air may settle on environmental surfaces, which could then become secondary vehicles for the spread of infectious agents indoors.…”