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

Infant rats were infected intranasally with mixtures of streptomycin-sensitive and streptomycin-resistant strains of Haemophilus influenzae type b and cultures of nasopharyngeal washings, blood, and cerebrospinal fluid were obtained. If the infecting organisms cooperated with each other during the establishment of infection, nasopharyngeal, blood, and cerebrospinal fluid cultures should have contained mixtures of the variants. If each organism acted independently, then with small infecting inocula all the organisms in nasopharynx, blood, or cerebrospinal fluid should be descended from a single bacterium. Cultures should then contain only one of the variants. Single variant nasopharyngeal cultures were obtained from 8 out of 19 (42%) rats when the intranasal inoculum was <100 organisms. As the inoculum was increased, single variant cultures were less frequently observed. When the inoculum was >/=10(5) organisms, nasopharyngeal cultures were always mixtures. Single variant blood cultures were obtained in 46 of 67 (68.7%) episodes of bacteremia when rats were inoculated intranasally with 10(8) organisms. Single variants were isolated from the cerebrospinal fluid of 13 of 19 (68.4%) rats with meningitis whose blood contained both streptomycin-sensitive and streptomycin-resistant variants. When the blood contained a single variant, this same variant was cultured from the cerebrospinal fluid on 39 of 40 (97.5%) occasions. These studies demonstrated that invasive. H. influenzae b infections of infant rats resulted from independent action, as opposed to cooperative interaction of intransally inoculated organisms. The results also suggested that the meninges were invaded by the hematogenous route.
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PMID:Haemophilus influenzae bacteremia and meningitis resulting from survival of a single organism. 30 28

Infant rats inoculated intraperitoneally with Haemophilus influenzae type b develop bacteremia and meningitis. Rats were infected at 10 to 12 days of age and studied for the development of serum anticapsular antibody and bactericidal and opsonizing activity. Seven and 11 weeks after inoculation, convalescent animals showed a higher frequency of anticapsular antibody responses than uninfected controls, but 35 to 40% of the infected group had undetectable levels of anticapsular antibody (<0.10 mug/ml). In contrast, all of the convalescent animals, but none of the controls, showed moderate titers of serum bactericidal activity; and bactericidal activity persisted after absorption of the convalescent sera with type b capsule. Bactericidal activity was detected primarily in the eluted fraction corresponding to a molecular weight of 150,000 and was present in the offspring of convalescent females. Offspring of convalescent females were protected against challenge with H. influenzae type b, and control offspring could also be protected by passive immunization with convalescent serum which lacked detectable anticapsular antibody. Convalescent serum samples efficiently opsonized H. influenzae type b, and this activity persisted after absorption of the serum with capsular antigen. These data are consistent with the hypothesis that antibody to the noncapsular surface antigens of H. influenzae type b play an important role in host defenses.
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PMID:Experimental Haemophilus influenzae type b meningitis: immunological investigation of the infant rat model. 30 39

Forty-seven infants and children with a variety of infections including bacteremia, ethmoiditis, and periorbital cellulitis, soft tissue infection, pneumonia, and lymphadenitis were treated with intravenous cefamandole. The infections were due to Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, and Haemophilus influenzae. The clinical response was prompt, and, with the exception of two cases who developed skin rash, significant side effects were not noted. In vitro cefamandole was very effective in inhibiting the growth of H. influenzae, including ampicillin-resistant isolates.
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PMID:Clinical and laboratory investigation of cefamandole in infections of infants and children. 30 39

The role of antibodies to capsular and somatic antigens in the clearance of Haemophilus influenzae was investigated by active and passive immunization. The clearance index (k) and the proportion of strain b organisms cleared 30 min after intravenous administration (deltaY30) were greater in eight-week-old actively immunized rats (k = 0.693, deltaY30 = 4.07) than in nonimmune animals (k = 0.075, deltaY30 = 0.95)(P less than 0.025 for all); however, clearance correlated imprecisely with titers of bactericidal or anticapsular antibody. In three-week-old rats, intranasal immunization with strain b or U significantly increased (P less than 0.005) the rate of clearance of strains b and U. Passive immunization with antibodies to somatic or capsular antigens significantly increased the rate of clearance (P less than 0.001) and the proportion of bacteria cleared (P less than 0.05) with all test strains. The increased clearance associated with passive immunization correlated with increased splenic uptake of 32P-labeled H. influenzae (r = 0.83, P less than 0.025). Analysis of the disappearance of viable organisms and bacterial 32P suggested that bacteriolysis of H. influenzae did not occur during clearance of the bacteremia. Either antibody to capsular antigen or antibody to somatic antigen, administered or evoked in rats, accelerates intravenous clearance of H. influenzae by promotion of reticuloendothelial phagocytosis.
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PMID:Role of immunity in the clearance of bacteremia due to Haemophilus influenzae. 30 94

Haemophilus influenzae is an important agent of bacteremia and has fastidious growth requirements. The purpose of this investigation was to determine the ability of commercial blood culture media to support the growth of this fastidious microorganism. Twenty-three types of blood culture media were inoculated with individual suspensions of eight strains of H. influenzae in the presence or absence of an erythrocyte-serum mixture. The rates of recovery of the H. influenzae strains from the various types of blood culture media were compared. The results demonstrated that the type of medium, the manufacturer, the erythrocyte-serum mixture, and the strain of H. influenzae influenced the recovery rates of H. influenzae. Optimal recovery of the strains of H. influenzae was obtained from brain heart infustion blood culture medium (GIBCO). Trypic soy broth (GIBCO) and supplemental peptone of Becton, Dickinson and Co. also were found to be superior to the remaining types of media tested for the recovery of H. influenzae.
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PMID:Recovery of Haemophilus influenzae from twenty-three blood culture media. 31 78

Six soft tissue infections (three epiglottitis, one cellulitis, one pneumonia, and one arthritis) with ampicillin-resistant Haemophilus influenzae were treated initially with high doses of ampicillin (200 to 400 mg/kg/day intravenously) alone and had good clinical responses. All had documented bacteremia with H. influenzae. One child was treated only with ampicillin; treatment in the remainder was changed to oral therapy with other antibiotics to facilitate discharge. There was no recurrence of disease. Disc diffusion studies done on clinical isolates of both resistant and sensitive organisms indicate a break point at which the resistant organism shows progressive sensitivity to increasingly higher concentrations of ampicillin.
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PMID:Treatment of ampicillin-resistant Haemophilus influenzae in soft tissue infections with high doses of ampicillin. 31 30

Children not initially admitted to the hospital accounted for 42 of 94 episodes of bacteremia due to Haemophilus influenzae. Antibiotics were prescribed for 22 of the 42 children who were initially sent home; at second visit, 17 were improved, including all 13 with pneumonia. No antibiotics were prescribed for 20 children; at second visit, 15 had persistent fever or new focal infection and five had resolution of symptoms. New diagnoses of focal infection were made at second visit in three of the 22 treated and in 11 of the 20 untreated children, including three who had a new diagnosis of meningitis (one treated with antibiotics initially; two not treated). Cultures of blood positive for H. influenzae were obtained at second visit in ten children who were not treated initially; no child who was treated initially had a second positive culture. These findings indicate that although young children with bacteremia due to H. influenzae may be mildly ill at first visit, many are at risk for development of serious focal infection, including meningitis.
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PMID:Unsuspected bacteremia due to Haemophilus influenzae: outcome in children not initially admitted to hospital. 31 72

Two cases of bacterial endocarditis caused by Haemophilus parainfluenzae are reported with a review of 33 other cases of H. parainfluenzae endocarditis and 5 cases of H. influenzae endocarditis. Although H. parainfluenzae is usually considered a non-pathogenic microorganism, this review firmly establishes its role as a causative agent in endocarditis. Furthermore, several clinical features were noted which were atypical when compared to findings usually present in patients with bacterial endocarditis. The mean age of the patients was only 27 years. Over 60% of the patients had no identifiable predisposing illness, an unexpected finding in view of the low degree of pathogenicity associated with this microorganism. Polymicrobial bacteremia, usually with viridans streptococci, was found in 11% of patients. Major arterial emboli were documented in 57% of patients, an incidence unchanged from the pre-antibiotic era. Diagnosis of the disease is dependent upon an awareness of the fastidious cultural requirements necessary for isolation of Haemophilus species. Culture media must contain a source of X and V factors. Mortality from H. parainfluenzae endocarditis has been reduced from 100 per cent prior to 1940 to about 12 per cent by use of appropriate antimicrobial agents. Awareness that Haemophilus species can cause bacterial endocarditis is important because the diagnosis is dependent upon utilization of special culture methods and the patient may not respond to some of the empiric regimens used for treating bacterial endocarditis. It should be especially considered as a possible cause of "culture-negative" or "abacteremic" endocarditis.
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PMID:Haemophilus parainfluenzae and influenzae endocarditis: a review of forty cases. 32 16

Neonatal gastrointestinal colonization of newborn rats with Escherichia coli 075:K100:H5, cross-reactive with the capsular polysaccharide of Haemophilus influenzae type b, was harmless but failed to stimulated detectable ( greater than 200 ng/ml) serum anticapsular antibodies. Neonatally colonized rats, when challenged at age 13 weeks by intraperitoneal inoculation of H. influenzae b, showed no difference in the frequency, magnitude, or duration of bacteremia or in the postinfection anticapsular antibody response when compared with saline-fed controls. However, neonatally colonized rats challenged at age 4 weeks had a significantly decreased incidence of sustained bacteremia and/or endophthalmitis when compared with controls. This decreased frequency of disease correlated with a significant increase in postinfection serum anticapsular antibodies. Neonatal gastrointestinal colonization with cross-reacting E. coli appears to "prime" the young host to respond to infection with H. influenzae b with an anticapsular antibody response that protects against sustained H. influenzae b bacteremia and its complications.
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PMID:Effect of neonatal gastrointestinal colonization with cross reacting Escherichia coli on anticapsular antibody production and bacteremia in experimental Haemophilus influenzae type b disease of rats. 32 98

The pathogenesis of bacterial meningitis was studied in infant rats. Intranasal intoculation of greater than 10(3) Haemophilus influenzae type b resulted in an incidence of bacteremia that was directly related to the size of hte challenge inoculum. The temporal and quantitative relationship of bacteremia to meningitis indicated that bacteria spread to the meninges by the hematogenous route and that the magnitude of bacteremia was a primary determinant in the development of meningitis. In a sparate series of experiments, infant rats that were fed Escherichia coli strain C94 (O7:K1:H-) became colonized and developed bacteremia and meningitis, but invasive disease was rare when rats were fed E. Coli strain Easter (O75:K100:H5). A comparison of intranasal vs. oral challenge indicated that the nasopharynx was the most effective route for inducing H. influenzae bacteremia, whereas the gastrointestinal route was the more effective challenge route for the E. coli K1 serotype.
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PMID:The infant rat as a model of bacterial meningitis. 33 Jul 77


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