Intra-abdominal Bacterial Infection Research Articles

A neutrophil-B-cell axis impacts tissue damage control in a mouse model of intraabdominal bacterial infection via Cxcr4.

Sepsis is a life-threatening condition characterized by uncontrolled systemic inflammation and coagulation, leading to multiorgan failure. Therapeutic options to prevent sepsis-associated immunopathology remain scarce. Here, we established a mouse model of long-lasting disease tolerance during severe sepsis, manifested by diminished immunothrombosis and organ damage in spite of a high pathogen burden. We found that both neutrophils and B cells emerged as key regulators of tissue integrity. Enduring changes in the transcriptional profile of neutrophils include upregulated Cxcr4 expression in protected, tolerant hosts. Neutrophil Cxcr4 upregulation required the presence of B cells, suggesting that B cells promoted disease tolerance by improving tissue damage control via the suppression of neutrophils' tissue-damaging properties. Finally, therapeutic administration of a Cxcr4 agonist successfully promoted tissue damage control and prevented liver damage during sepsis. Our findings highlight the importance of a critical B-cell/neutrophil interaction during sepsis and establish neutrophil Cxcr4 activation as a potential means to promote disease tolerance during sepsis.

Intra-Abdominal Candidiasis

Intra-abdominal candidiasis (IAC) is the second most common form of invasive candidiasis after candidaemia. IAC is a broad term and can be classified on the basis of anatomical site (Candida peritonitis, pancreatic candidiasis, biliary tract candidiasis, gastrointestinal candidiasis, and hepatosplenic candidiasis) as well as clinical setting (community acquired versus nosocomial). The risk factors linked with IAC are candida colonisation, anastomotic leak, multiple instrumentation, long-term broad spectrum antibiotic use, total parenteral nutrition, and immunocompromised state. Clinically, IAC is not different from intraabdominal bacterial infection. Patients generally present with signs and symptoms of intra-abdominal sepsis after not responding to antibiotic therapy and with a background history of multiple surgical interventions or history of delayed source control. Radiological investigations, like ultrasonography and computed tomography scan, not only aid in diagnosis but also assist in differentiating medical from surgical cases. Microbiological diagnosis requires isolation of candida from an intra-abdominal specimen. Differentiation between colonisation and infection is difficult. Generally, progressive and persistent colonisation is associated with high risk of infection. Blood cultures have poor sensitivity for IAC. Non-culture based techniques used for diagnosis are mannan/anti-mannan assay, beta-D glucan assay, and validated polymerase chain reaction. Four types of antifungal strategies described in the literature are prophylaxis (risk factor driven), pre-emptive (colonisation or biomarker driven), empirical (fever driven), and targeted therapy (microbiology driven). Over recent years, global epidemiology has shown a shift from Candida albicans to non-albicans. Local epidemiology plays an important role in selection of the appropriate empirical therapy. The purpose of this review is to discuss different types of IAC based on their classification, risk factors, and management.

Risk factors of intra-abdominal bacterial infection after liver transplantation in patients with hepatocellular carcinoma.

To explore the risk factors of intra-abdominal bacterial infection (IAI) after liver transplantation (LT) in patients with hepatocellular carcinoma (HCC). A series of 82 HCC patients who received LT surgeries in our department between March 2004 and April 2010 was recruited in this study. Then we collected and analyzed the clinical data retrospectively. Statistical analysis system (SPSS) software was adopted to perform statistical analysis. Chi-square test, t-test and Wilcoxon rank sum test were used to analyze the clinical data and compute the significance of the incidences of early-stage IAI after LT for HCC patients. Binary logistic regression was performed to screen out the risk factors, and multiple logistic regression analyses were performed to compute the independent risk factors. A series of 13 patients (13/82, 15.9%) had postoperative IAI. The independent risk factors of postoperative intra-abdominal bacterial infections after LT for HCC patients were preoperative anemia [Hemoglobin (HGB) <90 g/L] and postoperative abdominal hemorrhage (72 hours >400 mL), with the odds ratios at 8.121 (95% CI, 1.417 to 46.550, P=0.019) and 5.911 (95% CI, 1.112 to 31.432, P=0.037). Postoperative IAI after LT in patients with HCC was a common complication. Preoperative moderate to severe anemia, as well as postoperative intra-abdominal hemorrhage more than 400 mL within the first 72 hours might independently indicate high risk of IAI for these patients.

838 Abdominal Tuberculosis Due to Mycobacterium Bovis

BackgroundCurrently, disease related to Mycobacterium bovis (MB) is rare in Spain (less than 1% of tuberculosis cases). However, it’s more frequent in undeveloped countries where the way to become infected...

Outcomes of Intra-Abdominal Fungal vs. Bacterial Infections in Severe Acute Pancreatitis

Intra-abdominal infection in severe acute pancreatitis (SAP) has significant morbidity and mortality; however, reports conflict on the outcome of patients with intra-abdominal fungal infection (IFI). We aimed to compare the morbidity and mortality of IFI compared with intra-abdominal bacterial infection (IBI) and no intra-abdominal infection (NII) in patients with SAP. Medical records of 207 consecutive patients admitted with SAP (per the Atlanta classification) to the Mayo Clinic (Rochester, Minnesota) between 1992 and 2001 were reviewed. All intra-abdominal microbiology cultures from pancreatic and peri-pancreatic necrosis, abscess, and/or pseudocyst obtained at operation, endoscopic necrosectomy or computed tomography-guided aspiration were reviewed. Patients were divided into three groups-IFI, IBI, and NII. Primary fungal infections were those for which there had been no prior abdominal interventions, and secondary infections were those that followed a prior intervention. Our main outcome was in-hospital mortality and secondary outcomes included the presence of organ failure (OF), need for surgical intervention, need for intensive care unit (ICU) care, and duration of hospitalization. The groups were similar in terms of baseline characteristics, use of prophylactic antibiotics, use of enteral/parenteral nutrition, development of necrosis, and peripancreatic fluid collections. Fifty-two percent of patients had an intra-abdominal infection; all of these developed bacterial infections and 30 (15%) developed concomitant fungal infections. There were 7 primary fungal infections and 23 secondary infections-no important outcome differences were noted between these groups. Compared with patients with IBI, patients with IFI had longer hospital (63 vs. 37 days, P<0.01) and ICU (28 vs. 9 days, P<0.01) stays and higher rates of OF (73 vs. 47%, P<0.04), but similar mortality rates (20 vs. 17%, P0.41). Multivariate analysis revealed the presence of OF (odds ratio (OR) 2.4, 95% confidence interval (CI) 1,7) and the need for ICU care (OR 4.3, 95% CI 1,28) to be associated with IFI. Patients with SAP and IFI suffered greater in-hospital morbidity than did patients with IBI alone. Concomitant fungal infection, however, did not increase the in-hospital mortality rate.

Microbial tolerance in secondary peritonitis is dose dependent

Local microbial tolerance was investigated in a murine model of peritonitis. Peritoneal bacterial burden and inflammatory cytokine concentrations were determined at different times, within 48 h after infection. Peritoneal macrophages were harvested from naïve mice or from mice 48 h after infection and underwent ex vivo stimulation with different concentrations of Klebsiella. Cytokine secretion was determined in the supernatants. Peritoneal bacteria concentrations, remained relatively steady between 24 h (median: 5.04 log CFU) and 48 h (median: 5.19 log CFU) after infection. Peritoneal cytokine concentrations peaked early but were already diminished at 48 h after infection, despite persistent high bacteria levels. Macrophages, harvested from naïve mice responded vigorously to ex vivo stimulation with 10 5 CFU and 2 × 10 8 CFU Klebsiella. Cells harvested from animals 48 h after infection, were unresponsive to an ex vivo stimulation with 10 5 CFU Klebsiella, but fully responded to 10 8 CFU. Persistent intraabdominal bacterial infection induced dose dependent microbial tolerance in peritoneal macrophages.

Donor-Type Myelodysplastic Syndrome with t(2;3) and Monosomy 7 after Allogeneic Peripheral Blood Stem Cell Transplantation and Liver Transplantation in a Patient with Severe-Type Aplastic Anemia.

Secondary clonal hematological disease in donor cells has rarely been reported as a complication of allogeneic stem cell transplantation in hematological disease. We report a case of myelodysplastic syndrome that showed cytogenetic abnormalities of t(2;3) and monosomy 7, which developed two years after peripheral blood stem cell transplantation for aplastic anemia and one year after liver transplantation for drug-induced hepatic failure. A 23-year-old female was diagnosed as having a severe-type aplastic anemia in April, 2000. Treatment with immunosuppressive drugs was not successful. Nineteen months later, she received allogeneic PBSCT from an HLA-matched elder on November 12, 2001. Her clinical course after PBSCT was marked by serious drug-induced hepatitis. Ten months after allogeneic PBSCT, she suddenly developed hepatic failure. On September 29, 2002, she was emergently transplanted with living donor-derived liver from the sibling who was the donor for allogeneic PBSCT. One month after liver transplantation (LT), pancytopenia had gradually progressed. At that time, chromosomal analysis showed 46, XX (20/20), and chimerism analysis of PB showed 100% donor-type. Late graft rejection of bone marrow was not suspected due to there being no relative lymphocytosis and the persistence of 100% complete donor-type chimerism. Thereafter, pancytopenia worsened, even with the stable complete donor-type chimerism, and G-CSF and EPO were administered. Bone marrow aspirate at seven months after the start of cytokine therapy showed trilineage dysplasia, suggesting secondary myelodysplasia. Cytogenetic analysis at that time showed t(2;3) in 17/20 cells. Eight months later, at 31 months post allogeneic PBSCT and 21 months post-LT, her bone marrow showed chromosomal abnormality with t(2;3) and additional monosomy 7 in 14/20 cells. There was no evidence of graft rejection because of sustained 100% donor-type chimerism. There was no possibility of second SCT because of hepatic dysfunction and hyperbilirubinemia even after LT as well as repeated intra-abdominal bacterial infection through a gastrostomy tube for nutrition. Bone marrow aspirations performed two and six months later showed an increased proportion of t(2;3) and monosomy 7 to 100%. She suddenly died of intra-abdominal bleeding due to profound thrombocytopenia 42 months after allogeneic PBSCT and 32 months after LT. The donor is currently alive and well with completely normal hematological data. This secondary malignancy of donor origin is most frequently seen in patients with leukemia. We suspect that the chromosomal abnormalities are related to hepatitis-associated aplastic anemia, administration of granulocyte colony-stimulating factor and erythropoietin for post-transplant pancytopenia, and repeated infections after liver transplantation.

Dry-reagent strips for testing milk pasteurization

Biostrips have become more popular for diagnosis of various diseases as well as for testing of different chemical and biochemical parameters. Alkaline phosphatase (ALP) is an enzyme naturally present in raw milk, which is used as an indicator for proper milk pasteurization. Nonpasteurized or raw milk contains ALP, which causes intra-abdominal bacterial infection after drinking the milk, whereas after pasteurization, ALP is denatured. Therefore, milk industries test the milk after pasteurization using conventional methods such as colorimetric and fluorescence. Our attention was drawn to develop quick, simple and economical test using dry-reagent strips for detection of ALP activity in milk. It is based on ALP reaction with p-nitrophenyl phosphate in the presence of water to liberate p-nitrophenol and inorganic phosphate. p-Nitrophenol on reacting with a specific chromogen changes the colour of the strip from light blue to green, which is visualized by the naked eyes. The strip has a sensitivity of >0.5 units/L. The strips may be used in dairy industries and remote areas where expensive instruments are not available. The strip is stable for more than a year at room temperature.

Intra‐abdominal Bacterial Infection Reactivates Latent Pulmonary Cytomegalovirus in Immunocompetent Mice

Critically ill surgery patients are susceptible to pulmonary reactivation of latent cytomegalovirus (CMV), but what triggers this reactivation is unknown. Immunosuppression and bacterial sepsis are thought to stimulate reactivation of CMV, and in this study it was hypothesized that immunosuppressive effects of surgery with or without concomitant bacterial infection may reactivate latent CMV. Mice infected with CMV were allowed to develop latent infections. Latently infected mice underwent a laparotomy with cecal ligation and puncture (CLP; n=30), a laparotomy alone (sham; n=10), or no surgery (control; n=5). Lung tissue homogenates were evaluated for viral activity, and, 2 and 3 weeks after CLP, lungs of 7 of 7 and 5 of 5 mice, respectively, showed reactivation of latent CMV. In contrast, lungs from all sham-operated animals and controls showed no viral reactivation. These findings demonstrate that surgery with subsequent intra-abdominal bacterial infection reactivated CMV in lungs of latently infected mice. The mechanism of this reactivation is unknown but likely involves cytokines induced by sepsis.

The usefulness of conducting investigations on intra-abdominal bacterial contamination in digestive tract operations.

A bacteriological study of 108 cases of gastrointestinal surgery was conducted by analyzing intra-abdominal bacterial contamination (IABC) and postoperative surgical site infections (SSI). We utilized an anaerobic porter to detect intra-abdominal bacterial infection and transport bacteria to the laboratory. The positive IABC rate was 42.9% for gastric cancer surgery, 22.6% for biliary tract surgery, and 85.7% for colorectal cancer surgery. Most cases of SSI were IABC-positive, and isolated bacterial species from the SSI were similar to those from the IABC. In colorectal cancer surgery, a preoperative chemical intestinal preparation and the prophylactic use of antibiotics had a major influence on the sensitivity of bacteria isolated from the SSI. These data suggest that prophylactic antibiotics should be chosen from among those to which bacteria from the IABC are highly sensitive, and that therapeutic antibiotics should be chosen from among those to which bacteria isolated from the SSI are highly sensitive. Finally, the exploration of IABC enables us to predict the incidence of SSI.

Intra-abdominal Candida infection during acute necrotizing pancreatitis has a high prevalence and is associated with increased mortality.

To analyze the frequency of intra-abdominal Candida infection during acute necrotizing pancreatitis and to compare the outcome to patients without Candida infections. Retrospective analysis of data from 37 patients with and without Candida infection. Surgical intensive care unit (ICU) in a university hospital. Thirty-seven patients with acute necrotizing pancreatitis. Patients were subject to necrosectomy and programmed lavage. Clinical parameters contained in the Acute Physiology and Chronic Health Evaluation (APACHE) II score were monitored, as were microbiological results from the intra-abdominal primary focus and from sites of secondary infections. Body mass index, distribution of underlying diseases, length of ICU stay, number of operations, and outcome were recorded. Multivariate logistic regression analysis for mortality as the dependent variable was performed. Intra-abdominal Candida infection was observed in 13 of 37 cases and was associated with a four-fold greater mortality rate compared with intra-abdominal bacterial infection alone. Multivariate logistic regression analysis demonstrated that Candida infection contributed to mortality significantly (p < .025) and independently from APACHE II (p < .006; mortality odds ratio for the two parameters=12.5). Lack of antimycotic treatment was associated with an increase to 29.2 (p<.001) in the odds ratio. Given the impact of Candida infection on mortality to acute necrotizing pancreatitis and the apparent benefit from antimycotic chemotherapy, the data argue for an early fungicide chemotherapeutic intervention.

Does laparoscopy increase bacteremia and endotoxemia in a peritonitis model?

Laparoscopy is increasingly used in patients with intraabdominal bacterial infection although pneumoperitoneum may increase bacteremia by elevated intraabdominal pressure. The influence of laparotomy and laparoscopy on bacteremia, endotoxemia, and postoperative abscess formation was investigated in a rat model. Rats received intraperitoneally a standardized fecal inoculum and underwent laparotomy (n = 20), or laparoscopy (n = 20), or no further manipulation in the control group (n = 20). Bacteremia and endotoxemia were higher after laparotomy and laparoscopy compared to the control group (p = 0.01) 1 h after intervention. One hour after intervention, aerobic and anaerobic bacterial species were detected in the laparotomy group while only anaerobic bacteria were found in the other two groups. Although bacteremia and endotoxemia did not differ among the three groups after 1 week, the mean number of intraperitoneal abscesses was significantly higher (p < 0.05) after laparotomy (n = 10) compared with laparoscopy (n = 6) and control group (n = 5). Laparoscopy does not increase bacteremia and intraperitoneal abscess formation compared to laparotomy in an animal model of peritonitis.