Primary human herpesvirus 6 infection in young children.

BACKGROUND: Human herpesvirus 6 (HHV-6) is a recently discovered virus that, on the basis of serologic evidence, appears to infect most children by the age of three years. However, the clinical manifestations of primary HHV-6 infection have not been well defined. METHODS: We studied consecutive children two years old or younger who presented to an emergency ward with febrile illnesses. Our evaluation included the isolation of HHV-6 from peripheral-blood mononuclear cells, an immunofluorescent-antibody assay, the detection of HHV-6 by the polymerase chain reaction (PCR), and restriction-endonuclease-fragment profiles of HHV-6 isolates. RESULTS: HHV-6 was isolated from 34 of 243 acutely ill children (14 percent). The children with viremia had irritability, high temperatures (mean, 39.7 degrees C), and inflammation of tympanic membranes (in 21), but few other localizing signs. Two children were hospitalized, but all 34 recovered after an average of four days of fever. The rash characteristic of roseola, which has been associated with HHV-6 infection, was noted in only three children. In 29 children (85 percent), serum samples obtained during convalescence had at least a fourfold increase in IgG antibody titers; 4 infants less than three months old who presumably had maternal antibody did not have this increase. HHV-6 was isolated from blood obtained during convalescence in only one child, but in two thirds of the children the virus could be detected by PCR. The isolates had genomic heterogeneity, indicating the presence of multiple strains. CONCLUSIONS: Primary infection with HHV-6 is a major cause of acute febrile illness in young children. Such infection is associated with varied clinical manifestations, viremia, and the frequent persistence of the viral genome in mononuclear cells.

Risk of secondary bacterial infection in infants hospitalized with respiratory syncytial viral infection.

Because infants hospitalized with respiratory syncytial virus (RSV) infection frequently receive antibiotics, our study was undertaken to determine what the actual risk of secondary bacterial infections in patients with RSV infection is and what effect antibiotic treatment might have on the course of illness. In a 9-year prospective study of 1706 children hospitalized with acute respiratory illnesses, 565 children had documented RSV infections. A subsequent bacterial infection rarely developed in those with RSV lower respiratory tract disease. The rate of subsequent bacterial infection was 1.2% in the total group of children infected with RSV, and 0.6% in the 352 children who received no antibiotics. A significantly greater proportion (4.5%) of subsequent bacterial infections occurred in infants who received parenteral antibiotics (p = 0.01), and especially in a subgroup who received parenteral antibiotics for 5 or more days (11%, p less than 0.001). We conclude that the risk of secondary bacterial infection appears to be low for most infants with RSV infection. In a few infants given parenteral broad-spectrum antibiotics the risk may be greater, but whether this is related to the antibiotic therapy or to other risk factors is not clear.

Five years of experience with the exclusive use of amikacin in a neonatal intensive care unit.

From November 1, 1980, to December 31, 1985, 3959 infants were admitted to the neonatal intensive care unit and 2385 infants (60%) received 2791 courses of aminoglycoside therapy. Aminoglycoside use totaled 16,279 patient days of which 16,070 (98.7%) were with amikacin. From November 1, 1980, to January 31, 1983, 1017 pairs of pre- and posttreatment endotracheal or pharyngeal specimens yielded 318 Gram-negative bacteria isolates. From November 1, 1980, to December 31, 1985, Gram-negative bacteria were isolated from 381 clinical specimens. Of the 318 surveillance and 380 clinical isolates tested, 285 (90%) and 358 (94%), respectively, were susceptible to amikacin. Amikacin resistance did not increase during the study. Amikacin-resistant organisms were isolated more frequently from patients receiving multiple courses than those receiving single courses of amikacin and resistant organisms were not usually found before the administration of amikacin. None of the 15 amikacin-resistant isolates made 6'-N-aminoglycoside acetyltransferase and 3 isolates took up only small amounts of radiolabeled amikacin, suggesting that resistance was due to decreased permeability. The extensive use of amikacin in a neonatal intensive care unit for over 5 years did not result in an increase of amikacin-resistant Gram-negative bacteria.

The use of eye-nose goggles to control nosocomial respiratory syncytial virus infection.

We evaluated an eye-nose goggle to determine its usefulness in reducing nosocomial RSV infection in patients and staff members on our infant ward. During a community outbreak of RSV in 1984, infection was assessed by biweekly routine viral cultures on all ward personnel and patients and also by seroconversion in personnel. For three weeks staff members wore the goggles; two (5%) adults and one (6%) child acquired nosocomial infection. During the subsequent three-week study period, goggles were not used and 34% of personnel and 43% of susceptible infants became infected. The use of the disposable eye-nose goggles was associated with a significant decrease in nosocomial RSV infections (P less than .003 for staff and P less than .05 for contact infants).

Nosocomial viral infections: I. Epidemiology and significance.

Viral illnesses in Strong Memorial Hospital were monitored over a 17-month period. Using criteria based primarily on the incubation periods for a number of common virus infections, the infections we found were classified as hospital- or community-acquired. Hospital-acquired viral infections occurred on most hospital services; the majority of infections occurred on the pediatric and psychiatric services. Infections due to herpesviruses were seen more frequently in a group of patients aged 14 years or older, while infections in patients aged three years or younger were more likely to be due to respiratory syncytial virus, influenzavirus, adenovirus, or parainfluenza virus. Patients with nosocomial infections due to viruses were hospitalized an average of 9.3 days longer than uninfected controls; thus nosocomial viral infections result in increased costs of hospitalization.