Rapid diagnosis of Hemophilus influenzae type b infections by latex particle agglutination and counterimmunoelectrophoresis.

Latex particle agglutination and counterimmunoelectrophoresis techniques were compared in a clinical trial to demonstrate their sensitivity, specificity, and usefulness in the rapid diagnosis of invasive Hemophilus influenzae type b disease. LPA, a simplified LPA performed by house officers, and CIE used in this study detected 0.2, 0.5, and 1 to 10 ng/ml of Hib capsular antigen, respectively. One hundred-six illnesses suspected of being caused by Hib were evaluated prospectively by these assays. A total of 39 of these were confirmed by culture or detection of antigen or both. LPA and simplified LPA were more sensitive and specific than CIE in the diagnosis of Hib disease (P less than 0.01), especially in invasive disease other than meningitis. LPA is inexpensive, can be performed quickly, and detects all invasive Hib infections. The results emphasize the usefulness of antigen detection in the rapid diagnosis of Hib infections, demonstrate that LPA is more sensitive and specific than CIE, and can be conveniently performed by physicians.     

Hemophilus influenzae type b disease in a day-care center. Report of an outbreak.

Four episodes of serious Hemophilus influenzae type b infection occurred in three children attending a day-care center. This was 100 times the expected annual total. The pharyngeal carriage rate of Hib was 60% for siblings of patients, 20% for adult household contacts, and 5% for well children at the center. No carriers were found in control populations. Escherichia coli K100, which cross-reacts serologically with Hib, was found in rectal swabs of 20% of family contacts of patients and 3.5% of well children at the center. It was recovered from two of seven persons who carried Hib in the pharynx and two of 75 who did not (P = 0.035), suggesting that carriage of one organism may facilitate carriage of the other. In a randomized prospective trial with 85 patient contact, Hib carriage was eradicated in all of four carriers given ampicillin and in all of three given rifampin. There were no statistically significant differences in the rate of adverse reactions in the two treatment groups. No further cases were reported.     

Chlamydial infection of mothers and their infants.

In 340 women, cultured prospectively during their pregnancies, the rate of infection with Chlamydia trachomatis was 8.8%. The women with positive cultures tended to be younger and more often single and black than their counterparts with negative cultures. There were no statistically significant clinical differences between the two groups. Eighteen children born to Chlamydia culture-positive women and 16 born to negative women were followed for nine months to examine the potential effects of maternal infection on infant growth, development, and illness. Eleven of 18 study patients had culture or tear antibody evidence of Chlamydia infection, as opposed to one of the control subjects (P = 0.00093). Eight of these 11 had clinical conjunctivitis, and two of the eight developed pneumonia. Growth retardation and developmental abnormalities were not detected in either group. It is concluded that maternal carriage of C. trachomatis is associated with a high incidence of clinical illness in the offspring.     

History of convulsions and use of pertussis vaccine

Data on 2062 reports from the Monitoring System for Adverse Events Following Immunization, Centers for Disease Control (CDC), were analyzed to compare the risk of a personal or family history of convulsions in children who had a neurologic adverse event after receipt of diphtheria-tetanus-pertussis (DTP) vaccine with those who had a nonneurologic adverse event. Children with a neurologic event after DTP vaccine had a 7.2 times higher risk for personal history of convulsions (95% confidence limits 4.5 to 11.5) and a 4.5 times higher risk for family history of convulsions (95% confidence limits 3.1 to 6.7) than did children with an adverse event that did not affect the nervous system. Children with either a febrile or nonfebrile convulsion after receipt of DTP were significantly more likely to have a personal history of convulsions than children with a nonneurologic adverse event (P less than 0.0001). Children with a febrile convulsion after receipt of DTP but not children with nonfebrile convulsions were significantly more likely to have a family history of convulsions than those with a nonneurologic adverse event. It is recommended that pertussis vaccination be deferred in children with a personal history of a convulsion until it can be determined that an evolving neurologic disorder is not present. If such disorders are found, these children should be given the combined pediatric diphtheria and tetanus toxoids (DT) vaccine to complete the series.     

Pseudomonas cepacia colonization in patients with cystic fibrosis: risk factors and clinical outcome

During the period of 1979 to 1983, 38 patients with cystic fibrosis (CF) at the CF center of St. Christopher's Hospital for Children in Pennsylvania developed respiratory tract colonization with Pseudomonas cepacia. Seventeen (45%) of the patients with colonization died. Yearly incidence rates of P. cepacia colonization fluctuated between 1.3% and 6.1%, suggesting an endemic phenomenon. Case-control studies showed that severe underlying CF, use of aminoglycosides, and having a sibling with CF and P. cepacia colonization were significant risk factors for P. cepacia colonization. Once colonized with P. cepacia, patients with CF were likely to be hospitalized longer (P = 0.008) and to die sooner (P = 0.0001) than control patients with CF. Environmental and microbiologic studies did not identify a common source or mode of transmission of P. cepacia among patients. The results of this investigation suggest that P. cepacia colonization of patients with CF was endemic in the hospital, occurred more frequently in those with severe disease, and was associated with adverse clinical outcome.