Outbreaks of nosocomial rotavirus gastro-enteritis in a paediatric ward

Prospective surveillance of nosocomial viral infections during and after hospitalization at a university children's hospital

BACKGROUND

In Switzerland 5% to 10% of hospitalized adults acquire nosocomial infections (NI) but few data are available in children. Most former studies on NI in hospitalized children analyzed specific units or pathogens and neglected the postdischarge period. We aimed to prospectively assess viral NI occurring during and shortly after hospitalization in children.

METHODS

Prospective surveillance was performed during a 24-month period. Electronic standardized questionnaires were completed for each patient by physicians during hospital stay. On a ward-based rotational schedule, follow-up information was obtained from a subset of patients 1 week after hospital discharge. NI were defined using CDC recommendations.

RESULTS

Overall, 6250 patients (34,608 patient hospitalization days, PHD) were enrolled and 1272 patients were recruited for postdischarge surveillance. Mean hospitalization duration was 5 days. Fifty-two (0.8%) patients acquired 54 viral NI during hospitalization and 12 patients (1.1%) acquired 12 viral NI after hospital discharge (NI incidence: 1.9 per 1000 PHD including follow-up period). NI rate in infants was higher compared with children >12 months old (2.0% vs. 0.8%; P 0.05) and the infant ward also had the highest incidence (4.0 NI per 1000 PHD). Most NI were gastrointestinal tract infections with 55% caused by rotavirus infection. NI rates were highest between November and March.

CONCLUSIONS

A significant part of NI will only be detected if surveillance includes the immediate postdischarge period. Given the strong seasonality of pediatric NI, intensifying hygiene measurements particularly on infant wards and prior to the cold season would be beneficial in reducing NI incidence.

Modeling nosocomial transmission of rotavirus in pediatric wards

Nosocomial transmission of viral and bacterial infections is a major problem worldwide, affecting millions of patients (and causing hundreds of thousands of deaths) per year. Rotavirus infections affect most children worldwide at least once before age five. We present here deterministic and stochastic models for the transmission of rotavirus in a pediatric hospital ward and draw on published data to compare the efficacy of several possible control measures in reducing the number of infections during a 90-day outbreak, including cohorting, changes in healthcare worker-patient ratio, improving compliance with preventive hygiene measures, and vaccination. Although recently approved vaccines have potential to curtail most nosocomial rotavirus transmission in the future, even short-term improvement in preventive hygiene compliance following contact with symptomatic patients may significantly limit transmission as well, and remains an important control measure, especially where resources are limited.

Infection control, hospital epidemiology, and patient safety

Health care-acquired are a major risk for hospitalized children. Similar to adult patients, children are vulnerable to infections related to medical devices. Children also are at significant risk of nosocomial transmission of common pediatric viral illness, such as respiratory syncytial virus and varicella. In addition, pediatric patients have unique or incompletely developed immune system.

Suivi prospectif des diarrhées nosocomiales dans 28 services de pédiatrie du quart Sud-Est de la France au cours d’un trimestre d’hiver

The aim of this study was to evaluate the risk of hospital-acquired diarrhoea during an epidemic period through a prospective multicentre observational study. A systemic investigation of the hospital-acquired diarrhoea (occurring at least 48 h after hospital admission) was conducted through a standardised questionnaire from January to March 1999 in patients of 5 years old or less hospitalised in 28 wards (620 beds) belonging to 20 hospitals located in the south-east part of France. Overall, 241 cases of hospital-acquired diarrhoea were collected, corresponding to a prevalence of 3.3% (3.6% after exclusion of patients admitted for diarrhoea) and a density of incidence of 0.81 per 100 days of hospitalisation. The mean stay duration of hospital-infected patients was greater than 10 days, versus 3.9 days for the other children (P < 0.001). A readmission was required in 27% of the infected children. Rotavirus was involved in 97.8% of microbiologically documented cases (88%). In 50% of the cases, the hospital-acquired diarrhoea was seen in patients with bronchiolitis. Contact isolation measures were prescribed in 88.4% of the cases. These results stress that hospital-acquired diarrhoea represent an important medical and economic load for paediatric units and could be used as reference data to evaluate the impact of preventive measures, especially to reduce readmission and mean stay duration.

Rotavirus outbreak on a pediatric oncology floor: possible association with toys

BACKGROUND

Several outbreaks of rotavirus gastroenteritis have occurred in hospitals and day care centers. In the spring of 1997, an outbreak of rotavirus occurred on our pediatric unit. Aggressive infection control measures were instituted, and potential lapses in infection control were assessed.

METHODS

Memorial Sloan-Kettering Cancer Center is a 434-bed cancer hospital in New York City. The pediatric unit is a 42-bed ward with both bone marrow transplant patients and non-bone marrow transplant oncology patients. Nosocomially acquired rotavirus was defined as diarrhea, vomiting, or gastrointestinal upset with onset 48 hours or more after hospital admission, accompanied by a positive enzyme immunoassay for rotavirus antigen.

RESULTS

Between February 24 and April 4, 1997, 8 patients on the pediatric unit had nosocomial rotavirus. Aggressive infection control measures were instituted. Patients with rotavirus were cohorted and placed on contact precautions (strict handwashing, gloves, and gown). Investigation by the infection control team revealed that communal toys in the playroom were not being cleaned according to the weekly protocol.

CONCLUSIONS

An outbreak of nosocomial rotavirus occurred on our pediatric oncology unit. Shared toys may have served as fomites in the transmission of rotavirus.

[Evaluation of a prevention program against nosocomial rotavirus infections in a pediatric ward]

The incidence of nosocomial rotavirus infections was evaluated by a study made in the pediatric ward in Cholet during the winter of 1993-1994. A second study was performed three years later at the same place and in similar conditions in order to evaluate the efficacy of the prevention measures taken in between.

PATIENTS AND METHODS

All children below three years of age and admitted to hospital between 1 December 1996 and 15 March 1997 were included in the prospective study (348 children). Fecal specimens were collected for each patient at admission in order to search for rotavirus. Then, a second stool analysis was performed if diarrhea occurred during hospitalization or within 48 hours of discharge. These last cases were detected by a phone call.

RESULTS

Thirty percent of the children had diarrhea at admission to hospital (19.3% in 1993-1994). Rotavirus was present in 11.8% of the first stool analyses (8.6% in 1993-1994). The rotavirus nosocomial infection rate has decreased from 3.7% (13 cases) in 1993-1994 to 2.9% (ten cases). The mean length of hospitalization has also decreased from 2.7 to 1.6 days.

CONCLUSION

The decrease in the rotavirus nosocomial infection rate leads to enforcing the prevention measures, among which the most important seems to us to be the short length of stay. However, the study also shows the limits of prevention that are linked to the virus characteristics and the conditions of hospitalization.

VP7 and VP4 genotyping of human group A rotavirus in Buenos Aires, Argentina

Specific and sensitive tests for the detection and typing of group A rotavirus strains are needed for a more comprehensive knowledge of the epidemiology of rotaviral infection. In this study 500 stool specimens taken from 1996 to 1998 from children with acute diarrhea in Buenos Aires were examined. Group A rotavirus was unequivocally demonstrated in 62% of the samples tested by enzyme-linked immunosorbent assay (ELISA) for detection of VP6 antigen, polyacrylamide gel electrophoresis of double-stranded RNA, and reverse transcription-PCR (RT-PCR) for amplification of the VP7:G (1, 062 bp) and VP4:P (876 bp) genes. Only five positive specimens were found by RT-PCR but not by ELISA. G and P typing was carried out by nested amplification of variable sequences of the VP7 and the VP4 genes with six G- and five P-type-specific primers (multiplex PCR). Results obtained by this method showed the prevalence of the following G and P types: G1, 39%; G2, 43%; G4, 4%; P[8], 16%; P[4], 71%. Unexpectedly, the G-P type combination most frequently found was G2P[4] (43%) rather than G1P[8] (12%), which is the most commonly found worldwide. Unusual strains of the type G1P[4] accounted for 14% of the total, while mixed infections with more than one type were found in 10% of the samples. Detection of fecal rotavirus-specific immunoglobulin M (IgM) and IgA antibodies in consecutive samples of two patients taken at daily intervals demonstrated that high levels of IgM and IgA antibodies were detected on day 1 after the onset of disease and that the samples remained positive for about 10 days, after which virus shedding was no longer observed. Multiplex PCR offers a sensitive and specific alternative to determine the prevalence of group A rotavirus G and P types and to identify the emergence of uncommon strains, whereas detection of fecal IgM and IgA antibodies represents a useful supplement to virus detection for the diagnosis of current or recently acquired infections.

Monitoring rotavirus environmental contamination in a pediatric unit using polymerase chain reaction

Rotavirus environmental contamination in a pediatric unit was investigated. Surfaces were swabbed, then viruses eluted, ultracentrifuged, and detected by polymerase chain reaction (PCR) amplification. Of 55 samples, 25 (46%) tested positive. Rotavirus RNA was more prevalent on surfaces in direct contact with children (thermometers and play mats) than on other environmental surfaces (washbasins, door handles, etc). PCR has proved useful for monitoring rotavirus environmental contamination.