Parvovirus B19-associated hemophagocytic syndrome.

Parvovirus B19 is a recently described pathogen, associated with an increasing spectrum of clinical manifestations. We present the first reported case, to our knowledge, of parvovirus B19-associated hemophagocytic syndrome, in which the diagnosis of parvovirus infection was documented by the presence of B19-specific IgM and IgG antibodies. Pancytopenia resolved immediately following splenectomy and the patient recovered completely.

Kinetics of immunoglobulin transport into canine bronchial secretions.

Radiolabeled 125I Preparations of canine IgG, IgM, and F(ab')2 fragments of IgG were injected intramuscularly into normal dogs to quantitate the transfer of immunoglobulins from the intravascular space into the lower respiratory tract and to observe the clearance of these proteins from lung secretions. Respiratory fluids were sampled by serial broncho-alveolar lavages during a 3-4 week interval. Only a small portion (0.15%) of the passively administered IgG was recovered in respiratory specimens indicating that minimal transfer of humoral IgG occurs under normal conditions. Alteration of the IgG molecule by removal of the Fc portion almost eliminates its penetration into lung secretions. Furthermore, IgM, which is not a prominent component of normal lung secretions, is not detected in these secretions following passive intramuscular injection.

Improved antibiotic usage following introduction of a novel prescription system.

We investigated the impact of a novel antibiotic prescription system on antibiotic use. After a two-month baseline monitoring period, an antibiotic prescription form was introduced on surgical and medical wards, which obliged physicians to categorize antibiotic use as prophylactic, empirical (culture results unavailable), or therapeutic. Depending on the category, administration of antibiotics was automatically discontinued after two days (prophylactic), three days (empirical), or seven days (therapeutic) unless the physician renewed the order or specified an alternate duration of administration. In the subsequent two-month intervention period, 233 (60%) of 390 surgical patients received prophylactic antibiotics compared with 281 (68%) of 413 in the baseline period. Mean duration of prophylaxis was reduced from 4.9 +/- 2.4 days to 2.9 +/- 1.6 days. In the intervention period, 11% of patients received their first prophylactic dose postoperatively, compared with a 30% baseline rate. The percentage of urology patients receiving appropriate therapy for urinary tract infection increased from 38% to 89%. No significant changes in antibiotic use were noted on the medical service. This antibiotic prescription system may have a substantial impact on antibiotic use.

Nosocomial infections in a neonatal intensive care unit.

Based on five years of surveillance in a neonatal intensive care unit (NICU), host and therapeutic risk factors for nosocomial infection were determined and the impact of staffing and environment on the rate of nosocomial infection was evaluated. From January 1974 to February 1977, infants occupied a crowded, hectic NICU that lacked basic infection control features, and 5.2% of the infants had at least one major nosocomial infection. The risk of nosocomial infection was associated with low birth weight, patent ductus arteriosus, surgery, and multiple supportive measures. After a new NICU opened in February 1977, 0.9% of the patients had major nosocomial infections (relative risk [old nursery/new nursery] = 5.06; P less than 10(-5); 95% confidence interval, 2.62-9.73). Improvements included 50% more nurses, increased space per infant, convenient sinks, and isolation facilities. Host and therapeutic risk factors for nosocomial infections were comparable in the old and new nurseries. The decrease in the rate of nosocomial infections therefore appeared to be due to improved staffing and environment.

Nosocomial infection and death in a neonatal intensive care unit.

Based on five years of prospective surveillance in a neonatal intensive care unit (NICU), the association of nosocomial infection with death during hospitalization was studied. Low birth weight and patent ductus arteriosus (PDA) were the variables most strongly associated with nosocomial infection. After stratification for these variables, there was a persistent association between nosocomial infection and increased risk of death (relative risk = 1.96; 95% confidence interval, 1.09-4.44; P = 0.03). The relative risk of mortality with nosocomial infection was significantly modified (P = 0.02) by the presence of PDA (relative risk = 3.42; 95% confidence interval, 1.68-6.95 for infants without PDA; no effect for infants with PDA). Relocation of the NICU to an improved, better-staffed facility was associated with a significant decrease in the adjusted nosocomial infection rate (relative risk [old NICU/new NICU] = 9.73; 95% confidence interval, 4.30-22.0). This improvement was accompanied by a statistically insignificant reduction in the overall mortality because other causes of death, such as low birth weight and serious underlying disease, are much more common in this population and thus are more important determinants of outcome.

Evaluation of blood culture procedures in a pediatric hospital.

To determine optimal clinical laboratory techniques for detecting pediatric bacteremia, we studied 7,768 consecutive blood cultures in a 1-year period. Blood was inoculated into one vented 50-ml bottle of brucella broth with 0.05% sodium polyanetholsulfonate and one unvented 50-ml bottle of Columbia broth with 0.05% sodium polyanetholsulfonate and 0.05% cysteine. Bottles were visually examined for growth on days 1 through 7 and blindly subcultured aerobically and anaerobically on days 1, 2, and 7. There were 724 (9.3%) positive cultures, and 484 (6.2%) were clinically significant. The most frequent isolates from bacteremic patients were Haemophilus influenzae (24%) and Streptococcus pneumoniae (17%). Growth was noted in only one bottle in 25% of clinically significant isolates. Bottles inoculated with greater than or equal to 1 ml of blood became positive earlier than bottles inoculated with less than 1 ml. After 1 day of incubation, 48% of the clinically significant cultures showed growth on visual examination, whereas 85% showed growth on subculture. Only 19% of Haemophilus isolates were detected visually on day 1, whereas 88% were recovered on subculture. By day 7, 3.5% of all isolates (including 18% of pneumococcal isolates and 1% of Haemophilus isolates) could no longer be recovered on subculture. We conclude that a two-bottle blood culture system and blind subculture within 24 h will optimize detection of pediatric bacteremia.

Experimental pneumonia due to Pseudomonas aeruginosa in leukopenic dogs: prolongation of survival by combined treatment with passive antibody to Pseudomonas and granulocyte transfusions.

Treatment with type-specific IgG antibody to Pseudomonas aeruginosa significantly increased rates of survival after experimental induction of pseudomonas pneumonia in leukopenic dogs. Longer survival times were correlated with higher titers of circulating antibody in serum; however, no animals treated with antibody alone were long-term survivors. Subsequent development of sepsis or the recovery of Pseudomonas from infected lung tissue was not altered by treatment with antibody. Therapy with granulocyte transfusions plus gentamicin was associated with a 27% rate of long-term survival. Passive immunization with IgG (reciprocal mean hemagglutination titer, 52) in addition to granulocyte transfusions and treatment with gentamicin resulted in a rate of long-term survival of 67% (P less than 0.05). Dogs that died while receiving this combination therapy still had a survival time significantly longer than those of controls or animals treated only with granulocytes and antibiotic.

Chediak-Higashi syndrome: reversal of increased susceptibility to infection by bone marrow transplantation.

Transplantation of normal bone marrow to mice with the Chediak-Higashi syndrome (CHS) resulted in normal granulopoiesis and a reversal of their increased susceptibility to challenge with intravenous Candida albicans. These findings suggest that (1) the leukocyte defect in CHS can be reversed by marrow transplantation and (2) the mechanism for increased susceptibility to infection in these animals is due to a bone-marrow-derived cellular defect. Because of similarities between murine and human CHS, bone marrow transplantation might be considered as a mode of therapy in selected cases of the human disease.