Community-acquired Legionella Pneumonia in the intensive care unit: Impact on survival of combined antibiotic therapy.
ABSTRACT OBJECTIVES: To compare intensive care unit (ICU) mortality in patients with severe community-acquired pneumonia (SCAP) caused by Legionella pneumophila receiving combined therapy or monotherapy. METHODS: A prospective multicenter study was made, including all patients with sporadic, community-acquired Legionnaires' disease (LD) admitted to the ICU. Admission data and information on the course of the disease were recorded. Antibiotic prescriptions were left to the discretion of the attending physician and were not standardized. RESULTS: Twenty-five cases of SCAP due to L. pneumophila were included, and 7 patients (28%) out of 25 died after a median of 7 days of mechanical ventilation. Fifteen patients (60%) presented shock. Levofloxacin and clarithromycin were the antibiotics most commonly used in monotherapy, while the most frequent combination was rifampicin plus clarithromycin. Patients subjected to combination therapy presented a lower mortality rate versus patients subjected to monotherapy (odds ratio for death [OR] 0.15; 95%CI 0.02-1.04; p=0.08). In patients with shock, this association was stronger and proved statistically significant (OR for death 0.06; 95%CI 0.004-0.86; p=0.04). CONCLUSIONS: Combined antibiotic therapy decreases mortality in patients with SCAP and shock caused by L. pneumophila.
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ABSTRACT: Absolute lymphocytopenia is recognised as an important hallmark of the immune response to severe infection and observed in patients with Legionnaires' disease. To explore the immune response, we studied the dynamics of peripheral blood lymphocyte subpopulations in the acute and subacute phase of LD. EDTA-anticoagulated blood was obtained from eight patients on the day the diagnosis was made through detection of L. pneumophila serogroup 1 antigen in urine. A second blood sample was obtained in the subacute phase. Multiparametric flow cytometry was used to calculate lymphocyte counts and values for B-cells, T-cells, NK cells, CD4(+) and CD8(+) T-cells. Expression of activation markers was analysed. The values obtained in the subacute phase were compared with an age and gender matched control group. Absolute lymphocyte count (×10(9)/l, median and range) significantly increased from 0.8 (0.4-1.6) in the acute phase to 1.4 (0.8-3.4) in the subacute phase. B-cell count showed no significant change, while T-cell count (×10(6)/l, median and range) significantly increased in the subacute phase (495 (182-1024) versus 979 (507-2708), p = 0.012) as a result of significant increases in both CD4(+) and CD8(+) T-cell counts (374 (146-629) versus 763 (400-1507), p = 0.012 and 119 (29-328) versus 224 (107-862), p = 0.012). In the subacute phase of LD, significant increases were observed in absolute counts of activated CD4(+) T-cells, naïve CD4(+) T-cells and memory CD4(+) T-cells. In the CD8(+) T-cell compartment, activated CD8(+) T-cells, naïve CD8(+) T-cell and memory CD8(+) T-cells were significantly increased (p<0.05). The acute phase of LD is characterized by absolute lymphocytopenia, which recovers in the subacute phase with an increase in absolute T-cells and re-emergence of activated CD4(+) and CD8(+) T cells. These observations are in line with the suggested role for T-cell activation in the immune response to LD.PLoS ONE 01/2013; 8(4):e62265. · 3.73 Impact Factor