Reducing the rate of nosocomially transmitted respiratory syncytial virus.

BACKGROUND: A large number (17) of nosocomial respiratory syncytial virus cases led to the development of control measures to prevent transmission of respiratory syncytial virus (RSV) within the Johns Hopkins Hospital's Children's Center. METHODS: The control plan is based on a 2-stage process. In stage 1, the staff are notified that RSV is in the community, and information is distributed through a communication tree. Stage 2 requires that nasopharyngeal aspirates be obtained from all children <3 years of age who have respiratory symptoms. The aspirates are tested directly for RSV antigen and cultured for RSV. The children are placed on pediatric droplet precautions pending those results. RESULTS: The proportion of nosocomial RSV cases dropped from 16.5% before the use of RSV control measures to 7.2% after the initiation of the control program. A case of RSV identified in the hospital was 2.6 times more likely to be nosocomially acquired before the intervention compared with after the intervention. Approximately 14 cases of RSV are prevented each year, which results in a savings of 56 hospital-days and more than $84,000 in direct hospital-related charges alone. CONCLUSIONS: The nosocomial spread of RSV can be reduced by a specific and feasible control plan that includes early identification and rapid isolation of potential RSV cases.

Clinical trial of cefamandole, cefazolin, and cefuroxime for antibiotic prophylaxis in cardiac operations.

A relatively large number of comparative trials of antibiotic prophylaxis in cardiac surgery have been published, many of which have serious design flaws. Despite the large number of studies, no single antibiotic regimen has emerged as clearly superior in preventing postoperative site infections. To determine if a superior regimen could be identified with a study designed to avoid flaws found in previous studies, we undertook a randomized, double-blind clinical trial of three cephalosporins. From March 1987 to February 1990, 2759 adults underwent median sternotomies: 1641 completed study participation, 203 were enrolled but were dropped from the study for protocol violations, and 815 were excluded. The characteristics of all 2759 patients were recorded with respect to case mix and infection risk factors, and the patients were followed-up by the same nurse throughout hospitalization and for 6 weeks after discharge for the assessment of infection outcome status. Of the 1641 participants, 141 (8.6%) had one or more operative site infections: 46 of 549 (8.4%) cefamandole recipients, 46 of 547 (8.4%) cefazolin recipients, and 49 of 545 (9.0%) cefuroxime recipients (p = 0.92). The sites of infection and the depth of tissue involvement were not significantly different across groups. Because no differences in effectiveness in preventing postoperative site infections were demonstrated in a rigorously designed trial, the costs of the drugs, including the costs of their preparation and delivery, may be the only variables by which to choose among these three antibiotic prophylaxis regimens.

Seroprevalence of human immunodeficiency virus type 1 among pregnant women.

Five (0.74%) of 678 women delivering in 1985 at a tertiary referral hospital for high-risk pregnancies and 16 (1.34%) of 1198 women visiting an urban prenatal obstetrics clinic in 1986-1987 had serologic evidence of human immunodeficiency virus type 1 (HIV-1) infection. Unlinked testing (removal of personal identifiers from the blood specimen and the epidemiologic data sheet) of residual serum from hepatitis B virus serologic testing was used. Neither age, marital status, payor status, nor serologic markers of hepatitis B virus infection was useful in identifying women at risk for HIV-1 infection. As a result of these data, we have initiated a program in which counseling is offered to all women and testing for those who consent. Unlinked testing of women who refuse consent is performed for epidemiologic purposes. This will allow us to continue to plan for health care resource needs and to track the course of the epidemic in various subgroups of pregnant women.

Comparison of nasal brush and nasopharyngeal aspirate techniques in obtaining specimens for detection of respiratory syncytial viral antigen by immunofluorescence.

Diagnosis of respiratory syncytial virus by antigen detection is dependent on obtaining adequate respiratory epithelial cells. Two specimen collection methods, nasopharyngeal aspiration (NPA) and nasal brushing (NB), were compared. Thirty-two pediatric patients with presumed viral pneumonia or bronchiolitis (34 episodes) had both NPA and NB performed. Of 34 specimens 15 were culture-positive for respiratory syncytial virus. Of these 12 NPA samples and 10 NB samples had viral inclusions by immunofluorescent antibody staining (IFA). Of culture-negative samples, 1 of 17 NB was positive by IFA. One specimen obtained by NB had too few cells to read by the IFA method. Sensitivity and specificity were 80 and 100% for NPA and 67 and 94% for NB. Total respiratory cells and IFA-positive cells (classified as few, moderate, or many) were greater with NPA; however, NB was also an effective procedure and was better tolerated by children, less expensive and easier to perform.

Seroepidemiology of hepatitis B virus infection in the United States. 1976 to 1980.

The prevalence of hepatitis B virus (HBV) infection was determined using sera from persons participating in the second National Health and Nutrition Examination Survey, conducted from 1976 to 1980. Of 14,488 scientifically selected participants aged 12 to 74, 821 had evidence of past or present infection with HBV. In the white population, the weighted estimate of hepatitis B infection was 3.2 percent (95 percent confidence interval, 3.1 to 4.2). A steady increase with age was seen; by ages 65 to 74, the prevalence was 6.9 percent (95 percent confidence interval, 5.2 to 8.5). In the black population, the overall weighted estimate of prevalence was 13.7 percent (95 percent confidence interval, 11.6 to 15.8). In this racial group, there was a dramatic increase with age, with the oldest age groups having a prevalence of 39.6 percent (95 percent confidence interval, 29.1 to 50.0). In both racial groups, there was a low prevalence of infection in young children that began to rise between ages 12 and 18. In a multivariate analysis of factors associated with infection, there was an interaction of race with age; therefore, the odds ratio for race is presented for four ages. This ratio ranged from 3.0 (95 percent confidence interval, 1.8 to 4.2) for a 15-year-old to 8.2 (95 percent confidence interval, 6.5 to 10.3) for a 70-year-old. These relative odds estimates were not substantially affected by adjustment for the available information on risk factors for HBV infection. The results of this study in a representative sample of the United States population show that adult black Americans are at high risk for hepatitis B infection. Other independent predictors of HBV positivity include male sex; residing in the South, Northeast, or West; residing in a city of 250,000 or more people; serving in the armed forces; living below the poverty level; and having a positive treponemal test for syphilis. These data suggest that the immunization practices for controlling this disease should be re-examined.

Immunity to diphtheria and tetanus in inner-city women of childbearing age.

This study was conducted to determine immunity to diphtheria and tetanus in 232 inner-city women experiencing a recent birth. Forty-three (18.5 percent) of the women had levels of diphtheria antitoxin below the protective level (less than 0.01 unit/ml), whereas only 10 (4.3 percent) had insufficient levels of tetanus antitoxin. The percent of women susceptible increased with age, with 33 percent and 25 percent of women over the age of 30 years susceptible to diphtheria and tetanus, respectively.

Response of preterm infants to diphtheria-tetanus-pertussis vaccine.

The American Academy of Pediatrics recommendation that immunization of preterm infants with diphtheria-tetanus-pertussis (DTP) vaccine should begin at 2 months after birth, regardless of gestational age, is based on limited data. A prospective study was conducted to determine the immunogenicity and safety of DTP vaccine in preterm infants. One hundred ten preterm and 146 full term infants received doses of DTP at 2, 4 and 6 months after birth. Adjusted analysis of the antibody responses indicated that after three doses mean titers among preterm infants to each vaccine component were comparable to those of full term infants. Adjusted analysis of the incidence of adverse events indicated that the risk of adverse events in preterm infants was not significantly higher than that in full term infants. DTP vaccine is immunogenic and safe in preterm infants when the series is initiated at 2 months after birth, and this study supports the current recommendation of the American Academy of Pediatrics.

Gastrointestinal inflammation after bone marrow transplantation: graft-versus-host disease or opportunistic infection?

Gastrointestinal inflammation after allogeneic bone marrow transplantation may be due to acute graft-versus-host disease (GVHD) and/or superinfection with opportunistic organisms. Twenty-eight patients with barium studies suggesting gastrointestinal inflammation after bone marrow transplantation and either acute GVHD, viral infection, or both were studied to characterize the radiographic appearances of each disease and to determine whether acute GVHD could be distinguished from viral superinfection on the basis of radiographic findings. Thirteen patients had minimal or no acute GVHD, with viral infection proved in eight and strongly suspected in four others; the remaining patient was thought to have nonspecific inflammatory bowel disease. Five patients had pure acute GVHD, and 10 patients had viral enteritis superimposed on acute GVHD. Radiographic abnormalities were found in the gastrointestinal tract in both acute GVHD and viral infection and were more extensive than previously reported. Findings were similar in both entities, although gastric abnormalities were not seen in pure acute GVHD but only in viral infection, either alone or together with acute GVHD. Prolonged small bowel barium coating occurred in both viral infection and acute GVHD. Fold thickening evolved into fold effacement with a shaggy contour in two patients with viral infection. Colonic findings in all groups mimicked ulcerative colitis. Our data indicate that differentiation between acute GVHD and viral enteritis is not possible on the basis of radiographic findings alone. Both entities should be considered when gastrointestinal inflammation occurs after bone marrow transplantation.

Prevention of perinatal transmission of hepatitis B virus: the sensitivity, specificity, and predictive value of the recommended screening questions to detect high-risk women in an obstetric population.

The Advisory Committee on Immunization Practices recommends that all pregnant women be questioned concerning risk factors for hepatitis B virus infection and that those giving positive responses be serotested. The sensitivity, specificity, and predictive value of those recommended questions among 692 parturient women were determined. A total of 59 currently or previously infected women (hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs), or antibody to hepatitis B core antigen (anti-HBc) seropositive) were compared with the 633 seronegative women. Among nonwhite women, the sensitivity of a positive response to any one of the recommended questions was 60%. Specificity and positive predictive value were 71% and 19%, respectively. Among white women, the sensitivity, specificity, and positive predictive value were 56%, 75%, and 11%, respectively. To increase such unacceptably low sensitivity, the authors included two additional questions: single marital status and Medicaid/medical assistance payer status. Sensitivity increased to 96% among nonwhite women and 84% among white women. However, a positive response to at least one of the recommended questions or to additional questions was elicited from 78% of all women (92% nonwhite and 64% white). The authors conclude that to prevent perinatal transmission of hepatitis B, we must serotest all women in our obstetric population.

The critical role of 3-D CT reconstructions for defining spinal disease.

Three dimensional processing of routine CT images has previously been applied to osseous related maxillo-facial and spinal disorders. Two groups of patients, 25 with substantial spinal trauma and 25 with 'failed back' syndrome had 2-D and 3-D like displays processed by the Cemax 1000 system. The goal was to objectify whether the adjunct of 3-D imaging was truly valuable diagnostically. All images were recorded on 35 mm slides and projected both randomly and as an organized case; intra- and interpersonal evaluations were made. 3-D imaging in 19 of the 25 (76%) trauma patients disclosed additional diagnostic information which was considerably important to both the neuroradiologist and the referring surgeon. In the 'failed back' group, the 3-D images showed supplementary information in 15 of 25 (60%) cases. 3-D displays were usually in color showing complete regional information obtained from high resolution, medium thickness (4 mm) CT slices with minor overlapping (1 mm). The displays were optimized to the plane best defining the pertinent osseous and joint morphology; this included variably rotated and sometimes hemisected views. The images presented here are static, however, when viewed rapidly or by dynamic rotation, the regional morphology results in a highly graphic 3-D presentation.

Septic and technical complications of central venous catheterization. A prospective study of 200 consecutive patients.

The results of central venous catheterization for total parenteral nutrition were prospectively evaluated in 200 consecutive patients. All catheters were fabricated of polyurethane tubing inserted by the Seldinger technique. Two hundred sixty-three lines were inserted in 200 patients for a total of 4103 days. Major complications occurred in 2.3% patients. Twenty-four per cent of catheters were associated with suspected sepsis; of these, 52% were removed directly and 48% were changed over a guidewire. The total catheter sepsis rate was 5.7%. The incidence of sepsis correlated with the number of attempts to insert the line and with positive skin cultures. These data indicate that: use of the Seldinger technique to insert nonthrombogenic flexible catheters results in lower technical morbidity; the incidence of established infection is much lower than the incidence of suspected sepsis; guidewire change may be performed without risk to the patient or interruption of therapy; sepsis rates can be decreased by reducing the number of attempts to catheterize the subclavian vein; and sepsis rates correlate with positive skin cultures at the insertion site.

Methicillin-resistant Staphylococcus aureus (MRSA): risk and outcome of colonized vs. infected patients.

A retrospective study of 204 patients culture positive for methicillin-resistant Staphylococcus aureus compared infected and colonized patients. Seventy-eight patients were colonized and never developed infection (C), 24 were colonized and subsequently infected (C----I), and 102 patients had 1 or more nosocomial infections with MRSA at time of first culture (I). The most prevalent sites of infection were wound (26.5%) and blood-stream (20.7%), whereas the respiratory tract and surgical wounds were both frequent sites of colonization. Stepwise discriminant analysis found the most important factors in differentiating likelihood of colonization vs. infection were recent prior hospitalization, history of wound debridement, and number of invasive procedures. Ten percent of (C) died and 25.5% of (I) died. MRSA contributed to death in 57.6% of the (I) deaths (p less than .05). These results underscore the importance of differentiating (C) vs. (I) in hospitals where MRSA is endemic so that early specific treatment may be initiated. Risk factors for infection should be discriminated from those for acquisition of the organism.

Mediastinal infection after cardiac surgery.

Mediastinitis is an uncommon complication after cardiac surgery; however, its associated morbidity and mortality demand early recognition and emergency therapy. This review is intended to emphasize certain features of the incidence, pathogenesis, and bacteriology of this complication in patients undergoing cardiopulmonary bypass through a median sternotomy. The diagnosis and treatment of mediastinitis after cardiac surgical procedures, as well as methods of prevention, are also reviewed.

Comparison of broth and filtration methods for culturing of intravenous fluids.

Ninety-six specimens of intravenous fluid solutions (D5/025 NS) were inoculated with S. aureus, E. coli, P. aeruginosa, K. pneumoniae, E. agglomerans, or C. albicans in concentrations of .1, 1, 10, or 10(2) organisms/ml. They were cultured in tubes containing 5 ml of double enriched broth and after passage through a .45 mu pore membrane filter. After 24 hours of incubation, broth cultures were 68% as sensitive as the filter cultures (p less than .001). At the lowest concentration (.1 organism/ml) broth cultures wer only 45% as sensitive as the membrane filter technique after 24 hours of growth (p less than .001). Membrane filters provide a rapid method to accurately detect and quantitate the presence of microbial contamination even at very low levels of concentration. The simplicity and accuracy of the filtration method offers the clinician a valuable adjunct in managing suspected cases of intravenous fluid related sepsis.

An efficacy evaluation of a synergized glutaraldehyde-phenate solution in disinfecting respiratory therapy equipment contaminated during patient use.

Reusable, corrugated, expiratory limb ventilator tubing that had been in use for 24 hours, were randomly allocated to one of three groups: no treatment (N = 36); detergent wash (N = 83); or a detergent wash followed by a 10 minute immersion in a 1:16 dilution of synergized glutaraldehyde-phenate solution which was reused for 30 days. (Between 10 and 22 tubes were tested in each five day interval during this 30-day period.) Tubes were quantitatively and qualitatively cultured. There were significant differences in both the percent of contaminated tubes (no treatment = 92%, detergent wash = 72%, glutaraldehyde-phenate = 0 to 20%) and numbers of microorganisms per tube (no treatment = 3.2 x 10(6), detergent wash = 1.3 x 10(4), glutaraldehyde-phenate = 0 to 182) between groups. There was no apparent decrease in glutaraldehyde-phenate's efficacy throughout the 30-day reuse period, and in the final five days of the reuse period it was completely effective.

Infectious gastroenteritis in bone-marrow-transplant recipients.

We prospectively evaluated infections with several gastrointestinal pathogens in patients undergoing bone-marrow transplantation, in an attempt to correlate infection with morbidity and mortality. Thirty-one of 78 patients (40 per cent) were infected with one or more of the following enteric pathogens during the study: adenovirus (12 infections), rotavirus (nine), coxsackievirus (four), or Clostridium difficile (12). Several patients were infected with more than one pathogen. Infection correlated with the occurrence of diarrhea and abdominal cramps. The mortality rate among the infected patients was 55 per cent--significantly higher than the rate (13 per cent) among the noninfected patients (P less than 0.001). This study indicates that enteric pathogens that often cause mild diarrhea in normal populations can cause serious infections in marrow-transplant recipients. Measures aimed at preventing or treating such infections might reduce the morbidity and mortality associated with marrow transplantation.

Outbreak of Coxsackie A1 gastroenteritis: a complication of bone-marrow transplantation.

In a three-week period 7 of 14 transplant recipients were infected with coxsackie A1 virus. Diarrhoea and mortality were significantly associated with infection (7 of 7 infected compared with 0 of 7 non-infected, and 6 of 7 infected compared with 1 of 7 non-infected, respectively). Early in the outbreak, the diarrhoea was presumed to be due to acute graft-versus-host disease (AGVHD). However, the distribution of AGVHD among infected and non-infected patients was nearly equal, and at necropsy 3 of 6 infected patients who had had diarrhoea showed no evidence of gastrointestinal involvement with AGVHD. Infection with viral enteric pathogens may be an important factor in the clinical course of transplant recipients.