Comparison of two antigen detection techniques in a primate model of Haemophilus influenzae type b infection

Rapid diagnosis of Haemophilus influenzae type b meningitis is possible using immunological tests for capsular antigen (polyribophosphate, PRP), such as countercurrent immunoelectrophoresis (CIE) and latex particle agglutination (LPA). The authors compared 2 tests in monkeys with evolving, serially quantitated H. influenzae type b bacteremia (n = 23) and meningitis (n = 21). In vitro, the LPA test was sensitive to 0.5 ng of PRP/ml of saline, and the CIE test was sensitive to 1.0 ng/ml; in serum, however, CIE detected 5.0 ng of PRP/ml, whereas the sensitivity of LPA was unchanged. LPA detected PRP earlier in the course of bacteremia (mean, 12 hr after onset; range, 4 to 36 hr) than did CIE (mean, 45 hr; range, 4 to 168 hr) (P < 0.01). A positive LPA test required ≥ 100 bacteria per ml of blood, whereas CIE required ≥ 1,000/ml. PRP accumulated with continuing blood stream infection, aiding detection of low-grade bacteremia. LPA detected antigen in cerebrospinal fluid (CSF) earlier in the course of meningitis and at a lower bacteria density than did CIE. Both methods detected antigen reliably with ≥ 1,000 bacteria per ml of CSF. A close correlation existed between CSF concentrations of capsular antigen and bacteria (r = 0.90, P < 0.001). The authors conclude that the LPA method permits earlier diagnosis of H. influenzae type b infection in part because of its greater sensitivity

Comparison of two antigen detection techniques in a primate model of Haemophilus influenzae type b infection

Rapid diagnosis of Haemophilus influenzae type b meningitis is possible using immunological tests for capsular antigen (polyribophosphate, PRP), such as countercurrent immunoelectrophoresis (CIE) and latex particle agglutination (LPA). The authors compared 2 tests in monkeys with evolving, serially quantitated H. influenzae type b bacteremia (n = 23) and meningitis (n = 21). In vitro, the LPA test was sensitive to 0.5 ng of PRP/ml of saline, and the CIE test was sensitive to 1.0 ng/ml; in serum, however, CIE detected 5.0 ng of PRP/ml, whereas the sensitivity of LPA was unchanged. LPA detected PRP earlier in the course of bacteremia (mean, 12 hr after onset; range, 4 to 36 hr) than did CIE (mean, 45 hr; range, 4 to 168 hr) (P < 0.01). A positive LPA test required ≥ 100 bacteria per ml of blood, whereas CIE required ≥ 1,000/ml. PRP accumulated with continuing blood stream infection, aiding detection of low-grade bacteremia. LPA detected antigen in cerebrospinal fluid (CSF) earlier in the course of meningitis and at a lower bacteria density than did CIE. Both methods detected antigen reliably with ≥ 1,000 bacteria per ml of CSF. A close correlation existed between CSF concentrations of capsular antigen and bacteria (r = 0.90, P < 0.001). The authors conclude that the LPA method permits earlier diagnosis of H. influenzae type b infection in part because of its greater sensitivity

Prevalence of Toll-like receptor signalling defects in apparently healthy children who developed invasive pneumococcal infection

Human primary immunodeficiencies affecting Toll-like receptor (TLR) signalling reveal a non-redundant role for TLR function in defense against pneumococcal infection. To determine the clinical relevance of TLR abnormalities, we studied a population predicted to be enriched for TLR defects-healthy children who had developed invasive pneumococcal infection in the absence of classic risk factors for infection. We describe the development and optimization of a peripheral blood TLR assay. By testing 38 healthy control neonates, children and adults we demonstrated that TLR function was stable over the first six decades of life. We tested 50 children with a history of invasive pneumococcal infection and although TLR defects were predicted to be over-represented in this population, we did not identify any TLR abnormalities. Although TLR signalling defects are associated with greatly enhanced susceptibility to invasive pneumococcal infection, our results suggest that routine clinical screening for TLR defects in healthy children who develop invasive pneumococcal infection is not justified

Fever Management: Paediatric Nurses' Knowledge, Attitudes and Influencing Factors

ABSTRACT Background Despite evidence-based support for the beneficial effects of fever over the past three decades health professionals’ negative attitudes toward fever and reliance on antipyretics to reduce fever have persisted and continue to be reported in the literature. Aims This paper describes Australian paediatric nurses’ knowledge of and attitudes toward fever and fever management and the predictors of their intentions to administer paracetamol to a febrile child. Methods A self-report questionnaire identified knowledge, attitudes and factors influencing nurses’ intention to administer paracetamol to febrile children. Fifty-one paediatric nurses working in medical wards of a metropolitan paediatric hospital in Australia participated. An instrument was developed, piloted by test re-test and revised prior to data collection. Results Nurses’ mean knowledge about the physiology of fever, general fever management and antipyretics was 62%, not as high as expected. Participants reported positive attitudes toward the benefits of fever, the necessity for fever reduction in children with pre-existing cardiac or respiratory conditions and regular antipyretic administration masking the infective process. Negative attitudes included disbelief that temperature is often unrelated to illness severity. Conflicting attitudes toward febrile convulsions were highlighted by beliefs that antipyretic therapy prevents febrile convulsions and that antipyretics do not prevent initial febrile convulsions. Predictors of intentions to administer paracetamol were beliefs about the effectiveness of paracetamol and normative beliefs. Nurses reported strong intentions to administer paracetamol to the next febrile child they cared for. However, the use of a nurse manager for recruitment might have influenced socially desirable responses and undertaking the study at one site limits the generalisability of findings. Conclusions Fever management is an integral aspect of paediatric nursing. For consistent rational fever management nurses’ knowledge must improve, their positive attitudes enhanced and negative attitudes challenged. This highlights the need for continuing education in fever management