Microbes and infection
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The prevention of nosocomial infections is an important aspect of patient care, particularly in high-risk areas such as intensive care units (ICUs). Local hospital leadership needs to develop easily defined infection-control policies that are evidence-based. These infection-control policies also require the presence of a dedicated group of infection-control practitioners to provide education, collect surveillance data, and oversee the implementation of the local infection-control plan.
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Microbes and infection · Feb 2005
Respiratory nosocomial infections in the medical intensive care unit.
Intensive care unit (ICU)-acquired lower respiratory tract infections include acute tracheobronchitis and hospital-acquired and ventilator-associated pneumonia (VAP). Nosocomial pneumonia is the second most common hospital-acquired infection and the leading cause of death in hospital-acquired infections. The mortality rate in VAP ranges from 24% to 76% in several studies. ⋯ Once the physician decides to treat a suspected episode of ICU-acquired pneumonia, some issues should be kept on mind: first, the adequacy of the initial empiric antibiotic therapy; second, the modification of initial inadequate therapy according to microbiological results; third, the benefit of combination therapy; and finally, the duration of the antimicrobial treatment. Additionally, a protocolized work-up to identify the causes of non-response to treatment is mandatory. All these issues are discussed in depth in this article.
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Microbes and infection · Nov 2004
Essential role for the p40 subunit of interleukin-12 in neutrophil-mediated early host defense against pulmonary infection with Streptococcus pneumoniae: involvement of interferon-gamma.
Interleukin (IL)-12 is a critical cytokine in the T helper (Th)1 response and host defense against intracellular microorganisms, while its role in host resistance to extracellular bacteria remains elusive. In the present study, we elucidated the role of IL-12 in the early-phase host defense against acute pulmonary infection with Streptococcus pneumoniae, a typical extracellular bacterium, using IL-12p40 gene-disrupted (IL-12p40KO) mice. IL-12p40KO mice were highly susceptible to S. pneumoniae infection, as indicated by the shortened survival time, which was completely restored by the replacement therapy with recombinant (r) IL-12, and increased bacterial counts in the lung. ⋯ Neutralizing anti-IFN-gamma monoclonal antibody (mAb) significantly decreased the effect of rIL-12. Anti-IFN-gamma mAb shortened the survival time of infected mice and reduced the recruitment of neutrophils and production of MIP-2 and TNF-alpha in the lungs. Our results indicated that IL-12p40 plays a critical role in the early-phase host defense against S. pneumoniae infection by promoting the recruitment of neutrophils to the infected tissues.
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Microbes and infection · Nov 2004
IL-1 receptor-associated kinase 1 mediates protection against Staphylococcus aureus infection.
The interleukin-1 receptor-associated kinase-1 (IRAK-1) mediates signal transduction from Toll-like/IL-1/IL-18 receptors. Though a critical protective role against Staphylococcus aureus infection has been previously attributed to myeloid differentiation factor 88 (MyD88) and IRAK-4, both also involved in TLR/IL-1/IL-18 signaling, the role of IRAK-1 is unknown. IRAK-1-deficient (IRAK-1-/-) and wild-type mice were inoculated i.v. with 2 x 10(7) or 1 x 10(6) S. aureus per mouse to evaluate the role of IRAK-1 in S. aureus sepsis. ⋯ IRAK-1-/- mice are susceptible to a high dose of S. aureus compared to wild-type controls. In contrast to the high mortality and extensive weight loss seen in IL-1R-deficient mice in response to 1 x 10(6) S. aureus, IRAK-1-/- mice are resistant to this low dose of S. aureus. Thus IRAK-1 plays an important role in the host response to staphylococcal sepsis.