Hospital-Acquired Pneumonia: Pathophysiology, Diagnosis, and Treatment

Kieninger, Alicia N.; Lipsett, Pamela A.

doi:10.1016/j.suc.2008.11.001

Cited by 57 publications

(49 citation statements)

References 111 publications

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“…Pseudomonas aeruginosa is an opportunistic pathogen of immunocompromised humans which typically infects the pulmonary tract, causing bacterial pneumonia (17). Notably, hospital-acquired pneumonia in mechanically ventilated patients is associated with a particularly high mortality rate (18,19). Moreover, P. aeruginosa can also lead to eye and ear infections, complicated intra-abdominal infections, urinary tract infections, and skin and soft tissue infections (20, 21).…”

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confidence: 99%

Pseudomonas aeruginosa and Its Bacterial Components Influence the Cytokine Response in Thymocytes and Splenocytes

et al. 2016

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Infections with Pseudomonas aeruginosa may cause many different diseases. The spectrum of such infections in general includes inflammation and bacterial sepsis. Hospital-acquired pneumonia, naturally resistant to a wide range of antibiotics, is associated with a particularly high mortality rate in mechanically ventilated patients. The pathogenesis of P. aeruginosa is complex and mediated by several virulence factors, as well as cell-associated factors. We have previously demonstrated that stimulation with different bacteria triggers the cytokine response of thymocytes. In this study, we investigated the effect of P. aeruginosa and its different components on the cytokine production of immature and mature immune cells. We found that the induced cytokine pattern in the thymus and the spleen after infections with P. aeruginosa is primarily mediated by lipopolysaccharide (LPS) of the outer cell membrane, but other components of the bacterium can influence the cytokine secretion as well. Stimulation with heatkilled P. aeruginosa and LPS does not influence the amount of cytokine-producing CD4 ؉ T cells but instead suppresses the emergence of Th17 cells. However, stimulation with P. aeruginosa or its components triggers the interleukin-17 (IL-17) response both in thymocytes and in splenocytes. We conclude that infections with P. aeruginosa affect the cytokine secretion of immature and mature cells and that IL-17 and Th17 cells play only a minor role in the development of pathological systemic inflammatory disease conditions during P. aeruginosa infections. Therefore, other inflammatory immune responses must be responsible for septic reactions of the host. Interleukin-17 (IL-17) is a potent inflammatory cytokine, which was initially reported to be produced mainly by activated memory T cells, also called T helper (Th) 17 cells (1). In addition to induced IL-17-producing T cells, which are primed in the immune periphery during the induction of an antigen-specific T cell response, these IL-17-producing cells are also present in the thymuses of naive wild-type mice (2, 3). In most mice, IL-17-producing thymocytes represent a subpopulation of CD4 ϩ T cells which are able to react immediately on environmental stimuli without further priming phase (2-5). Furthermore, innate immune cells can also produce IL-17 in response to early immune mechanisms (6). Intrinsically, IL-17-producing cells, also referred to as the sentinels of the immune system, play a critical role in several fields of innate and adaptive immunity, including immunity against microbial infections and tumors (6-9). Dysregulated IL-17 production can result in uncontrolled proinflammatory cytokine production and chronic inflammation, promoting tissue damage and leading to autoimmune diseases (10-12). The most commonly used animal model for the human inflammatory demyelinating disease multiple sclerosis is experimental autoimmune encephalomyelitis (EAE) (13).Systemic bacterial infections and bacterial sepsis are dangerous and potentially lethal disease conditions t...

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confidence: 99%

Pseudomonas aeruginosa and Its Bacterial Components Influence the Cytokine Response in Thymocytes and Splenocytes

et al. 2016

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“…The high rate of HAIs is of great concern not for its impact on the health of ICU patients, but financially as well. Catheter-associated urinary tract infections account for 34% of all HAIs while CLABSI accounts for 14 % (Klevens et al, 2007) and VAP for 15 % respectively (Kieninger & Lipsett, 2009). This study focused on the two most frequent HAIs.…”

Section: Development Of Hais Is Multifactorial and May Include Invasimentioning

confidence: 99%

“…The majority of the published reports and studies to date focus on preventive measures (Drakulovic et al, 1999;Elpern et al, 2009;Grap et al, 2003;Munro et al, 2009;Shahin, Dassen, & Halfens, 2009), diagnostic procedures (Kollef et al, 2008;Sole et al, 2002), mortality (Kieninger & Lipsett, 2009;Keoning & Truwit, 2006), morbidity (Combes et al, 2004), length of stay (Pyenson et al, 2007;Shorr, Combes, Kollef, & Chastre, 2006;Williams et al, 2010), and cost (Combes et al, 2004;Maki & Tambyah, 2001;Safdar, Dezfulian, Collard, & Saint, 2005;Scott, 2009). HAIs are a resulting complication of multifactor events associated with healthcare personnel and healthcare circumstances.…”

Section: Patient Outcomesmentioning

confidence: 99%

“…VAP, accounting for 15% of all HAIs, is frequently lethal, contributes greatly to increased health care costs, and accounts for higher indexes of morbidity and mortality (Kieninger & Lipsett, 2009). Eighty six percent of healthcare-associated pneumonias are associated with mechanical ventilation (Koenig & Truwit, 2006).…”

Section: Ventilator-associated Pneumonia (Vap)mentioning

confidence: 99%

“…The pathogenesis of VAP is multifactorial (Kieninger & Lipsett, 2009). Invasion of pulmonary tissue in patients with VAP typically arises from aspiration of secretions, colonization of the tract (i.e., biofilm), and use of contaminated equipment (Coffin et al, 2008).…”

Section: Ventilator-associated Pneumonia (Vap)mentioning

confidence: 99%

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