Sources of Airborne Norovirus in Hospital Outbreaks.

BACKGROUND: Noroviruses are the major cause of viral gastroenteritis. Disease transmission is difficult to prevent and outbreaks in health-care facilities commonly occur. Contact with infected persons and contaminated environments are believed to be the main routes of transmission. However, noroviruses have recently been found in aerosols and airborne transmission has been suggested. The aim of our study was to investigate associations between symptoms of gastroenteritis and the presence of airborne norovirus, and to investigate the size of norovirus-carrying particles. METHODS: Air sampling was repeatedly performed close to 26 patients with norovirus infections. Samples were analyzed for norovirus RNA by reverse transcription quantitative polymerase chain reaction. The times since each patient's last episodes of vomiting and diarrhea were recorded. Size-separating aerosol particle collection was performed. RESULTS: Norovirus RNA was found in 21 (24%) of 86 air samples from 10 different patients. Only air samples during outbreaks, or before a succeeding outbreak, tested positive for norovirus RNA. Airborne norovirus RNA was also strongly associated with a shorter time period since the last vomiting episode (odds ratio 8.1; P = .04 within 3 hours since the last vomiting episode). The concentrations of airborne norovirus ranged from 5-215 copies/m3, and detectable amounts of norovirus RNA were found in particles <0.95 µm and >4.51 µm. CONCLUSIONS: The results suggest that recent vomiting is the major source of airborne norovirus and imply a connection between airborne norovirus and outbreaks. The presence of norovirus RNA in submicrometre particles indicates that airborne transmission can be an important transmission route.

Hydrogen peroxide vapour treatment inactivates norovirus but has limited effect on post-treatment viral RNA levels.

BACKGROUND: Hydrogen peroxide vapour is used as a room disinfectant. Its activity against murine norovirus, a surrogate viability marker for human norovirus, indicates that it is also active against human norovirus. AIM: The aim of this study is to assess how this effect on viability is reflected in measurements of RNA by quantitative PCR (qPCR). METHODS: Faeces suspensions of two human norovirus field strains, genogroup I and II and one cultured murine norovirus strain, (genogroup V) were dried on plastic plates, and underwent hydrogen peroxide vapour treatment or were mock treated. The influence of hydrogen peroxide on RNA was measured on genogroups I, II and V by qPCRs and for the cultivable murine norovirus also for viability by cell culture. Virucidal activity on murine norovirus was measured by endpoint titrations as the 50% tissue culture infectious dose, based both on cytopathic effect and on presence of replicating intracellular minus strand RNA. RESULTS: The mean impact on the human norovirus qPCRs was 0.4 log10. The murine norovirus qPCR changed by 1.7 log10 but by an alternative qPCR only by 0.4 log10. These minor changes contrasted the 4.5-5.0 log10 murine norovirus viability reduction after treatment measured by cytopathic effect or intracellular negative-strand RNA. CONCLUSION: Inactivation of murine norovirus viability by hydrogen peroxide vapour was not reflected in qPCR levels. This finding might be extrapolated to the related human norovirus genogroups. We further found that cellular minus strand murine norovirus PCR was an observer-independent marker to study reduction of murine norovirus viability.

Hydrogen Peroxide Vapor Decontamination in a Patient Room Using Feline Calicivirus and Murine Norovirus as Surrogate Markers for Human Norovirus.

OBJECTIVE: To determine whether hydrogen peroxide vapor (HPV) could be used to decontaminate caliciviruses from surfaces in a patient room. DESIGN: Feline calicivirus (FCV) and murine norovirus (MNV) were used as surrogate viability markers to mimic the noncultivable human norovirus. Cell culture supernatants of FCV and MNV were dried in triplicate 35-mm wells of 6-well plastic plates. These plates were placed in various positions in a nonoccupied patient room that was subsequently exposed to HPV. Control plates were positioned in a similar room but were never exposed to HPV. METHODS: Virucidal activity was measured in cell culture by reduction in 50% tissue culture infective dose titer for FCV and by both 50% tissue culture infective dose titer and plaque reduction for MNV. RESULTS: Neither viable FCV nor viable MNV could be detected in the test room after HPV treatment. At least 3.65 log reduction for FCV and at least 3.67 log reduction for MNV were found by 50% tissue culture infective dose. With plaque assay, measurable reduction for MNV was at least 2.85 log units. CONCLUSIONS: The successful inactivation of both surrogate viruses indicates that HPV could be a useful tool for surface decontamination of a patient room contaminated by norovirus. Hence nosocomial spread to subsequent patients can be avoided.

Design for the post-antibiotic era: experiences from a new building for infectious diseases in malmö, sweden.

OBJECTIVE: To describe the experience of planning and designing a new facility for infectious diseases in Sweden and to discuss underlying theories relating to infection prevention and evidence-based design. BACKGROUND: Departments of Infectious Diseases are common in healthcare facililties in Sweden. In 2005, a decision was made to build a new facility. The program required spacious single rooms, with a high ventilation standard, and anterooms. METHODS: In this article we present an analysis of the future of infectious diseases. Underlying theories are discussed. We also describe how a program was outlined using literature studies, including evidence-based healthcare design, focus groups of staff, and study visits. RESULTS: Active involvement of users and infection control specialists was important in the building process. A full-scale patient room mock-up was built with ventilation, electrical, and other systems. The mock-up was cost effective because it avoided costly mistakes during the building process. The mock-up also was a place where staff could assess and begin adapting to their future work environment. Separate ventilation and separate entrances to patient rooms from the building exterior allowed placement of isolation units in the main hospital area. CONCLUSIONS: Antimicrobial resistance, emerging diseases, healthcare associated infections, and outbreaks highlight the need for infection control measures in all hospital design. Infection control should be integrated in all hospital planning and be part of contracts. In this study we describe a specialized unit where a high degree of standardization and flexibility has made it possible to have a unique standard of preparedness for the post-antibiotic era. KEYWORDS: Design process, evidence-based design, infection control, planning, safety.

Human wound infections caused by Neisseria animaloris and Neisseria zoodegmatis, former CDC Group EF-4a and EF-4b.

BACKGROUND: Neisseria animaloris and Neisseria zoodegmatis, former CDC Group EF-4a and -4b, are considered to be rare zoonotic pathogens, usually associated with dog or cat bites. The aim of the study was to phenotypicaly characterize 13 EF-4 isolates from wound infections, determine their antibiotic susceptibility and to follow the clinical outcome of the patients. METHODS: 13 of the EF-4 isolates were cultured on agar plates. Conventional biochemical tests and the Biolog system were used for phenotypical identification. An arbitrary primed polymerase chain reaction (AP-PCR) was carried out to determine the genetic profiles. Minimum inhibitory concentration (MIC) values were determined for different antibiotics were determined. According to this, clinical data for the patients were recorded. RESULTS: 11 isolates were identified as N. animaloris and 2 as N. zoodegmatis due to the production of arginine dihydrolase. A majority of the patients had a history of dog bite. In 6 cases only grewth of N. animaloris or zoodegmatis was registered. When a patient received antibiotic treatment the most common drug of choice was penicillin V. Only 3 patients received treatment for which the isolated EF-4 bacterium was fully susceptible. CONCLUSION: Human infections involving N. animaloris and N. zoodegmatis usually present themselves as local wound infection, but severe complications can occur. Despite their pathogenic potentia, l N. animaloris and N. zoodegmatis are often misidentified, dismissed as skin contaminants or not recognized at all. Due to the fact that N. animaloris and N. zoodegmatis are significant pathogens in animal bites, physicians should keep these bacteria in mind when choosing antibiotic therapy.

Eradication of nasopharyngeal carriage of penicillin-non-susceptible Streptococcus pneumoniae--is it possible?

BACKGROUND: The South Swedish Pneumococcal Intervention Project (SSPIP) was started in 1995 with the aim of limiting the spread of penicillin-non-susceptible pneumococci (PNSP) in Skåne County, Sweden. As part of the SSPIP, eradication therapy with rifampicin in combination with 1 more antibiotic was considered on a social indication after prolonged carriage of 2-3 months. METHODS: In this retrospective study, 125 medical records were analyzed. Children aged 0-10 y referred for eradication therapy in Malmö and Lund, due to a prolonged nasopharyngeal carriage of PNSP with a penicillin G minimum inhibitory concentration of ≥ 0.5 mg/l, between the y 1997 and 2011 were included. Two consecutive negative cultures, with the second one no shorter than 7 days after treatment completion, were required for the carriage to be considered eradicated. RESULTS: Out of 125 children, 71 received treatment with rifampicin in combination with amoxicillin (n = 44), erythromycin (n = 22), or clindamycin (n = 5) for 7 days. Eradication treatment was successful in 91.5% of the children. Six children (8.5%) had treatment failure with amoxicillin and rifampicin; 3 were found by late follow-up. There was a trend towards a better outcome with erythromycin and clindamycin combinations in comparison to amoxicillin. CONCLUSIONS: Eradication therapy was successful, but a proper follow-up is essential.