Search

Introduction Although major changes of the immune system have been described in sepsis, it has never been studied whether these may differ in relation to the type of underlying infection or not. This was studied for the first time. Methods The statuses of the innate and adaptive immune systems were prospectively compared in 505 patients. Whole blood was sampled within less than 24 hours of advent of sepsis; white blood cells were stained with monoclonal antibodies and analyzed though a flow cytometer. Results Expression of HLA-DR was significantly decreased among patients with severe sepsis/shock due to acute pyelonephritis and intraabdominal infections compared with sepsis. The rate of apoptosis of natural killer (NK) cells differed significantly among patients with severe sepsis/shock due to ventilator-associated pneumonia (VAP) and hospital-acquired pneumonia (HAP) compared with sepsis. The rate of apoptosis of NKT cells differed significantly among patients with severe sepsis/shock due to acute pyelonephritis, primary bacteremia and VAP/HAP compared with sepsis. Regarding adaptive immunity, absolute counts of CD4-lymphocytes were significantly decreased among patients with severe sepsis/shock due to community-acquired pneumonia (CAP) and intraabdominal infections compared with sepsis. Absolute counts of B-lymphocytes were significantly decreased among patients with severe sepsis/shock due to CAP compared with sepsis. Conclusions Major differences of the early statuses of the innate and adaptive immune systems exist between sepsis and severe sepsis/shock in relation to the underlying type of infection. These results may have a major impact on therapeutics.

We read with interest the study by Batacchi and colleagues in a recent issue of Critical Care [1]. Vacuum-assisted closure (VAC) decompression is promising for the management of open abdomen, but our limited experience with this system suggests that dissemination of bacteria may occur. Recently, two patients were treated with VAC in our intensive care unit (ICU). Patient 1 was a 62-year-old man who was originally operated on for paraganglioma and underwent left nephrectomy and gastrojejunal anastomosis. Patient 2 was a 54-year-old woman who was admitted to the ICU two months after a complicated laparoscopic sleeve gastrectomy for morbid obesity. In both patients, at a certain point during their course, intra-abdominal sepsis developed, and they were both managed with extensive debridement, drainage, and VAC placement. Both patients developed fistulas, and although dressings and VAC pump containers were meticulously changed, leaks were repeatedly observed around the dressings. Furthermore, 2 to 4 weeks after the placement of VAC, a rise of positive cultures for Gram-negative bacteria was observed in all patients in our ICU (Figure ​(Figure1).1). As depicted in Figure ​Figure2,2, Klebsiella pneumoniae species became prevalent in our flora despite barrier measures and the isolation of both patients in a separate ward. In 12 out of 34 cases, KPC K. pneumoniae was isolated, whereas in one case it was resistant to all antibiotics. Figure 1 Number of positive Gram-negative and Gram-positive cultures in our intensive care unit during the stay of patients 1 (left) and 2 (right). The arrows represent the time of vacuum-assisted closure placement for each patient. Figure 2 Number of Klebsiella pneumoniae-positive cultures during the stay of patients 1 and 2. The solid arrow represents vacuum-assisted closure (VAC) placement in patient 1. The dotted arrow represents VAC placement in patient 2. Recent literature is inconclusive on this subject. We believe that further studies are needed to confirm the dissemination of bacteria from patients with VAC devices and abdominal leaks.