Successful Small Intestine Colonization of Adult Mice by Vibrio cholerae Requires Ketamine Anesthesia and Accessory Toxins

Vibrio cholerae colonizes the small intestine of adult C57BL/6 mice. In this study, the physical and genetic parameters that facilitate this colonization were investigated. Successful colonization was found to depend upon anesthesia with ketamine-xylazine and neutralization of stomach acid with sodium bicarbonate, but not streptomycin treatment. A variety of common mouse strains were colonized by O1, O139, and non-O1/non-O139 strains. All combinations of mutants in the genes for hemolysin, the multifunctional, autoprocessing RTX toxin (MARTX), and hemagglutinin/protease were assessed, and it was found that hemolysin and MARTX are each sufficient for colonization after a low dose infection. Overall, this study suggests that, after intragastric inoculation, V. cholerae encounters barriers to infection including an acidic environment and an immediate immune response that is circumvented by sodium bicarbonate and the anti-inflammatory effects of ketamine-xylazine. After initial adherence in the small intestine, the bacteria are subjected to additional clearance mechanisms that are evaded by the independent toxic action of hemolysin or MARTX. Once colonization is established, it is suggested that, in humans, these now persisting bacteria initiate synthesis of the major virulence factors to cause cholera disease. This adult mouse model of intestinal V. cholerae infection, now well-characterized and fully optimized, should serve as a valuable tool for studies of pathogenesis and testing vaccine efficacy

Temporary Closure of the Open Abdomen: A Systematic Review on Delayed Primary Fascial Closure in Patients with an Open Abdomen

Background This study was designed to systematically review the literature to assess which temporary abdominal closure (TAC) technique is associated with the highest delayed primary fascial closure (FC) rate. In some cases of abdominal trauma or infection, edema or packing precludes fascial closure after laparotomy. This "open abdomen'' must then be temporarily closed. However, the FC rate varies between techniques. Methods The Cochrane Register of Controlled Trials, MEDLINE, and EMBASE databases were searched until December 2007. References were checked for additional studies. Search criteria included (synonyms of) "open abdomen,'' "fascial closure,'' "vacuum,'' "reapproximation,'' and "ventral hernia.'' Open abdomen was defined as "the inability to close the abdominal fascia after laparotomy.'' Two reviewers independently extracted data from original articles by using a predefined checklist. Results The search identified 154 abstracts of which 96 were considered relevant. No comparative studies were identified. After reading them, 51 articles, including 57 case series were included. The techniques described were vacuum-assisted closure (VAC; 8 series), vacuum pack (15 series), artificial burr (4 series), Mesh/sheet (16 series), zipper (7 series), silo (3 series), skin closure (2 series), dynamic retention sutures (DRS), and loose packing (1 series each). The highest FC rates were seen in the artificial burr (90%), DRS (85%), and VAC (60%). The lowest mortality rates were seen in the artificial burr (17%), VAC (18%), and DRS (23%). Conclusions These results suggest that the artificial burr and the VAC are associated with the highest FC rates and the lowest mortality rate

Vacuum-assisted wound closure and mesh-mediated fascial traction - A novel technique for late closure of the open abdomen

Background Open abdomen (OA) treatment often results in difficulties in closing the abdomen. Highest closure rates are seen with the vacuum-assisted wound closure (VAWC) technique. However, we have experienced occasional failures with this technique in cases with severe visceral swelling needing longer treatment periods with open abdomen. Feasibility and short-term outcome of a novel combination of techniques for managing the open abdomen are presented. Methods The VAWC technique was combined with medial traction of the fasciae through a temporary mesh in seven consecutive patients. The VAWC-system was changed and the mesh tightened every 2-3 days. Results Median (range) age in the 7 men was 65 (17-78) years. The diagnoses were ruptured abdominal aortic aneurysm (AAA) (3), operation for juxtarenal AAA (1), iatrogenic aortic lesion (1), trauma (1) and abdominal abscesses (1). Four patients were decompressed due to abdominal compartment syndrome (ACS) or intra-abdominal hypertension, and 3 could not be closed after laparotomy. Intra-abdominal pressure prior to OA treatment was 24 (17-36) mmHg. Maximal separation of the fasciae was 16 (7 -30) cm. Delayed primary closure was achieved in all patients after 32 (12-52) days with OA. No recurrent ACS was seen. No technique-specific complication was observed. Two small incisional hernias, one intra-abdominal abscess and one wound infection occurred in three patients. Conclusions Delayed primary closure in cases with severe visceral swelling and long periods of OA seems feasible with this technique