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Query: UMLS:C0004610 (bacteremia)
 13,199 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism(s) by which the lipopolysaccharide (LPS) of Haemophilus influenzae type b may contribute to the virulence of this organism is unclear. Purified LPS of Haemophilus influenzae type b or phosphate buffered saline was administered intranasally to infant rats prior to the intranasal instillation of approximately 2-20 x 10(6) cfu of Hib two or three times per day for three consecutive days. The preadministration of 2.0 micrograms Hib LPS resulted in a significantly greater incidence of bacteremia (P = 0.0006) than PBS 30 min after the completion of the intranasal inoculation. Four days following completion of intranasal Hib inoculation the incidence of bacteremia was greater (P = 0.017) in the animals pretreated with LPS at 2.0 micrograms compared to the PBS pretreated animals. Preadministration of 0.2 micrograms LPS had no effect on the incidence of bacteremia or meningitis. There were no differences in the histology of the nasal cavities or turbinates of infant rats inoculated intranasally only with LPS or PBS. There were no differences in the frequency or density of bacteremia following intranasal administration of LPS from either Hib or E. coli. Although the mechanism is unknown, our findings suggest that the LPS of Hib may contribute to the ability of H. influenzae type b to invade the nasal mucosa in this infant rat model.
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PMID:Contribution of Haemophilus influenzae type b lipopolysaccharide to pathogenesis of infection. 307 63

To identify risk factors for the development of bacterial meningitis, we compared clinical characteristics in children with occult bacteremia who did and those who did not subsequently develop bacterial meningitis. The estimates of risk were adjusted for the possible confounding effects of other characteristics by using logistic regression. Of 310 children (median age 15 months) who had occult bacteremia with Streptococcus pneumoniae, Haemophilus influenzae type b, or Neisseria meningitidis at either Yale-New Haven Hospital or Children's Hospital of Pittsburgh, bacterial meningitis subsequently developed in 22 (7%). Compared with the risk associated with occult bacteremia with S. pneumoniae, the adjusted relative risk for bacterial meningitis was 85.6 (P less than 0.0001) and 12.0 (P = 0.0001) for N. meningitidis and H. influenzae type b, respectively. By contrast, the adjusted relative risk associated with a lumbar puncture at the initial visit was only 1.2 (P = 0.78). The development of bacterial meningitis in children with occult bacteremia is strongly associated with the species of bacteria that causes the infection, but not with a lumbar puncture or with other clinical characteristics identifiable at the initial visit.
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PMID:Risk factors for development of bacterial meningitis among children with occult bacteremia. 308 42

We have determined the time course of radiometric detection of microbial growth in 2348 positive blood culture specimens obtained at Wyler Children's Hospital during a 5-year interval. Overall 72 and 88% of isolates were detected within 48 and 72 hours after sampling, respectively. For pathogenic organisms aerobic detection was generally more rapid and more inclusive than anaerobic detection. At 48 hours of incubation the detection of six potential pathogens (Salmonella sp., Haemophilus influenzae, Group D streptococci, Neisseria meningitidis, coagulase-negative staphylococci, Candida sp.) was significantly delayed compared with detection of other pathogenic organisms recovered from blood. At 72 hours of incubation the detection rates remained less than 95% for H. influenzae, Staphylococcus aureus, Klebsiella sp., coagulase-negative staphylococci, Group D streptococci and Candida sp. These data should assist clinical decisions regarding duration of antibiotic therapy for the presumptive diagnosis of bacteremia in children.
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PMID:Time course of radiometric detection of positive blood cultures in childhood. 308 49

150 infected patients from 2 study centers had body fluids examined for presence of bacterial antigens (group B streptococcus, Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b) using the Pharmacia Phadebact system. The rates of detection of the pneumococcal antigens in the urine or serum of the patients with pneumococcal pneumonia, pneumococcal bacteremia and pneumococcal meningitis were 0.38, 0.47 and 0.5, respectively. The overall detection rate for H. influenzae infections was 0.92 and for group B streptococcal infections 0.87. Serum and urine from 100 non-infected patients were also tested for the presence of group B streptococcus, S. pneumoniae, N. meningitidis and H. influenzae type b antigens with only 1 false positive (H. influenzae type b).
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PMID:Detection of bacterial antigens in body fluids by the Phadebact system. 309 38

Although asplenic individuals are at higher risk for infection with encapsulated bacteria, it is not known whether they require a higher concentration of anticapsular antibody than normal individuals do for protection against invasive disease caused by Haemophilus influenzae type b. At 21 days of age, rats were passively immunized with human hyperimmune serum globulin against H. influenzae b polysaccharide (or saline) after recovery from splenectomy or a sham operation. Starting at 18 h after immunization, rats received three intranasal inoculations of 10(7) CFU of H. influenzae b over the next 24 h. Of sham-operated rats given 0.75 or 3.0 micrograms of anticapsular antibody, 91 or 96%, respectively, were protected from bacteremia, whereas only 59 and 67% of similarly treated asplenic rats were protected (P less than 0.004, control versus asplenic rats). A 12-microgram antibody dose resulted in the complete protection of both groups. The magnitude of bacteria was significantly higher in the asplenic group at each dose of antibody. Thus, asplenic hosts may require a higher concentration of anticapsular antibody than normal individuals do for protection against invasive H. influenzae b disease.
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PMID:Anticapsular antibody requirements for protection against experimental Haemophilus influenzae type b bacteremia after splenectomy. 325 41

To evaluate the possibility that immunization with a capsular polysaccharide vaccine decreases immunity in the immediate postvaccination period and renders an animal susceptible to invasive Haemophilus influenzae type b disease, we passively immunized infant rat pups with an immune globulin preparation, vaccinated them with an H. Influenzae type b capsular polysaccharide vaccine at a wide range of doses, and challenged them with H. influenzae type b given intraperitoneally. Bacteremia occurred in 89% of protected, vaccinated pups compared with 17% of protected, unvaccinated pups (p = 0.0001). In protected, vaccinated pups the rate of bacteremia resembled that in unprotected, unvaccinated control pups and did not vary with the dose of vaccine administered. The magnitude of bacteremia and the incidence of meningitis in protected, vaccinated pups exceeded that occurring in the protected, unvaccinated control animals, but these effects diminished with the dose of vaccine. Diminution of anticapsular antibody occurred in association with the largest doses of vaccine. We conclude (1) that the administration of H. influenzae type b capsular polysaccharide vaccine in infant rats is associated with a diminution of passively acquired anticapsular antibody immediately after vaccination and (2) that experimental challenge with H. influenzae type b at this time produces disease resembling that in animals not passively given protection.
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PMID:Postvaccination susceptibility to invasive Haemophilus influenzae type b disease in infant rats. 326 86

In the course of using the infant rat model to determine the ability of various rabbit antisera to protect against challenge by Haemophilus influenzae type b we made two unexpected observations. In these experiments 4-day-old rats were inoculated s.c. on the dorsum with either rabbit serum or physiological buffers (sham serum) and then were challenged the next day with H. influenzae type b injected i.p. Bacteremia, as a marker for disease, was measured 24 h later on day 6. We observed the following. (i) Pre-immune, i.e., normal rabbit serum, containing minimal levels of antibodies to outer membrane proteins and depleted of antibodies to capsule and lipopolysaccharide, nevertheless significantly (P less than 0.01) protected the rats from challenge with H. influenzae type b when compared to a sham inoculation of buffer; (ii) In the absence of a serum inoculation on day 4 (a buffer was used as a sham serum inoculation), the levels of bacteremia obtained after inoculation with bacteria on day 5 depended upon the composition of the buffer in which the H. influenzae inoculum was suspended. Use of phosphate buffered saline (PBS) resulted in higher levels of bacteremia than PBS containing 0.5% bovine serum albumin (PBS-BSA) (P less than 0.001), i.e. the BSA apparently acted to protect the rats from H. influenzae infection. In fact the use of PBS-BSA as an inoculum buffer masked the protective effect noted above of the absorbed normal rabbit serum.
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PMID:Unexpected effects of absorbed normal rabbit serum and bovine serum albumin on survival of Haemophilus influenzae type b in the infant rat. 326 78

Bacteraemia with Haemophilus pneumonia is uncommon. To determine its incidence and features case notes of patients in whom Haemophilus spp. were isolated from blood and pleural fluid over a five-year period were reviewed. Eight adult patients with H. influenzae bacteraemia were identified, five of whom had pneumonia on clinical and radiographic criteria. Only one patient had a predisposing factor, chronic obstructive lung disease. Two patients had beta-lactamase producing isolates, one of whom developed an empyema, following treatment with ampicillin, which required surgical drainage. Four patients were elderly, aged 69-80 yrs and were clinically in shock at the time of diagnosis. Seven of the eight patients survived.
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PMID:Bacteraemic Haemophilus influenzae pneumonia. 326 67

We report a series of 60 children with epiglottitis, 42 who were admitted via our emergency room and 18 who were transferred to Children's Hospital of Michigan (CHM) after initial airway management elsewhere. Patients managed entirely at CHM had lateral neck x-rays performed (diagnostic in each case), and underwent nasotracheal intubation in the operating room. There was no mortality or permanent morbidity in this group. Transferred patients were managed in a variety of ways at their referring institutions, sometimes without an artificial airway. Complications in this group included transient hypoxic encephalopathy (three children) and permanent severe encephalopathy (one child); four other children died. Blood cultures were positive for Hemophilus influenzae type b in 96% of the entire series. This study illustrates the importance of a consistent, well-organized approach to the diagnosis and management of epiglottitis, the reliability of a lateral neck x-ray, the high incidence of H. influenzae bacteremia, and the efficacy of nasotracheal intubation for maintaining airway patency in this disease.
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PMID:Acute epiglottitis in children: a conservative approach to diagnosis and management. 348 44

A collection of 242 strains of Haemophilus influenzae, including 65 nontypable (unencapsulated) isolates and 177 encapsulated serotype b isolates recovered largely from children with invasive and noninvasive diseases in the United States, was characterized by the electrophoretic mobilities of 15 metabolic enzymes presumably encoded by chromosomal genes. All enzymes were polymorphic for three to seven electromorphs, and 94 distinctive multilocus genotypes (electrophoretic types [ETs]) were distinguished, among which mean genetic (allelic) diversity was 0.500. Isolates recovered from cases of invasive or noninvasive diseases did not differ significantly in level of genetic variation. The observation that 29 ETs were represented exclusively by serotype b isolates and that each of the 65 nontypable isolates was of a unique ET strongly confirmed the hypothesis that unencapsulated clinical isolates are not merely phenotypic variants of the common serotype b cell lines. Rather, the two types of isolates are distinctive subsets of the multilocus chromosomal genotypes of the species as a whole. Serotype b capsule occurred in three groups of isolates that are distantly related in multilocus enzyme genotype. Isolates of four closely related nontypable biotype IV ETs associated with obstetrical infections or neonatal bacteremia were highly divergent from all others examined and may be specifically distinct. A phylogenetic scenario was proposed in which the ancestor of H. influenzae was encapsulated and the nontypable clones arose by convergent evolutionary loss of the ability to synthesize or extracellularly express a polysaccharide capsule.
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PMID:Genetic relationships of serologically nontypable and serotype b strains of Haemophilus influenzae. 348 74


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