Causative bacteria associated with a clinically relevant postoperative pancreatic fistula infection after distal pancreatectomy.

PURPOSE: Clinically relevant postoperative pancreatic fistulas (CR-POPF) occurring after distal pancreatectomy often cause intra-abdominal infections. We monitored the presence of bacterial contamination in the ascitic fluid after distal pancreatectomy to clarify the bacterial origin of intra-abdominal infections associated with CR-POPF. METHODS: In 176 patients who underwent distal pancreatectomy, ascitic fluid bacterial cultures were performed on postoperative days (POD) 1-4 and when the drainage fluid became turbid. The association between postoperative ascitic bacterial contamination and CR-POPF incidence was investigated. RESULTS: CR-POPF occurred in 18 cases (10.2%). Among the patients with CR-POPF, bacterial contamination was detected in 0% on POD 1, in 38.9% on POD 4, and in 72.2% on the day (median, day 9.5) when the drainage fluid became turbid. A univariate analysis revealed a significant difference in ascitic bacterial contamination on POD 4 (p < 0.001) and amylase level on POD 3-4 (p < 0.001). A multivariate analysis revealed the amylase level and ascitic bacterial contamination on POD 4 to be independent risk factors. CONCLUSIONS: In the CR-POPF group, ascitic bacterial contamination was not observed in the early postoperative stage, but the bacterial contamination rate increased after pancreatic juice leakage occurred. Therefore, CR-POPF-related infections in distal pancreatectomy may be caused by a retrograde infection of pancreatic juice.

High risk pathogens and risk factors for postoperative pancreatic fistula after pancreatectomy; a retrospective case-controlled study.

BACKGROUND: Although the rates of surgical site infection are decreasing, surgical site infection after pancreatectomy remains frequent because of postoperative pancreatic fistula. Recent studies suggested a relationship between postoperative pancreatic fistula and pathogens cultured from drainage fluids after pancreatectomy. This study aimed to assess and evaluate high-risk pathogens cultured from postoperative drainage fluids for postoperative pancreatic fistulas or severe postoperative complications after pancreatectomy. MATERIALS AND METHODS: We retrospectively enrolled patients who underwent pancreaticoduodenectomy or distal pancreatectomy between 2012 and 2019. We assessed clinical characteristics and microbiological results of drainage cultures of pancreaticoduodenectomy or distal pancreatectomy patients, and we investigated the risk factors for clinically relevant postoperative pancreatic fistulas and Clavien-Dindo status using univariate and multivariate analyses. Finally, we detected high-risk pathogens from drainage cultures and analyzed the correlation between these pathogens and the severity of clinically relevant postoperative pancreatic fistula or Clavien-Dindo status. RESULTS: Four hundred and twenty-nine patients were enrolled: 257 underwent pancreaticoduodenectomy and 172 underwent distal pancreatectomy. Clinically relevant postoperative pancreatic fistulas and Clavien-Dindo status ≥ III were more frequently seen in pancreaticoduodenectomy patients than in distal pancreatectomy patients, namely grade C postoperative pancreatic fistula, which was observed in 19 pancreaticoduodenectomy patients. The most common pathogen found from drainage cultures was Enterococcus species, followed by Enterobacter species and Candida species. All pathogens were associated with clinically relevant postoperative pancreatic fistulas; however, Candida species was a dominant microorganism of clinically relevant postoperative pancreatic fistulas grade C, Clavien-Dindo status ≥ IV, and hemorrhage due to pseudoaneurysm. CONCLUSION: The presence of Candida species in the drainage fluid culture after pancreaticoduodenectomy can be a predictive factor of severe infectious complications, including postoperative pancreatic fistulas; thus, we should regularly collect cultures from drainage fluids and monitor for Candida infection.

Association of bacteria in pancreatic fistula fluid with complications after pancreatic surgery.

BACKGROUND: Pancreatic fistula (PF) is a common complication after pancreatic surgery. It is unclear how microbes in PF fluid affect outcomes and which microbes are present after pancreatoduodenectomy (PD) and distal pancreatectomy (DP). The aim of this study was to compare the microbiological spectrum of PF fluid after PD versus DP, and its association with postoperative complications. METHODS: Bacterial strains and antibiotic resistance rates of bacterial swabs obtained from the PF fluid of patients who underwent DP or PD were analysed. Cultured bacteria were classified as Enterobacterales and as 'other intestinal and non-intestinal microorganisms' based on whether they are typically part of the normal human intestinal flora. RESULTS: A total of 847 patients had a pancreatic resection (PD 600; DP 247) between July 2007 and December 2016. Clinically relevant PF was detected in 131 patients (15·5 per cent). Bacterial swabs were obtained from 108 patients (DP 47; PD 61), of which 19 (17·6 per cent) were sterile. Enterobacterales were detected in 74 per cent of PF fluid swabs after PD, and in 34 per cent after DP. Infected, polymicrobial or multidrug-resistant PF fluid was more common after PD (rates of 95, 50 and 48 per cent respectively) than after DP (66, 26 and 6 per cent respectively). Patients with higher grade complications (Clavien-Dindo grade IV-V) or grade C PF had more Enterobacterales and multidrug-resistant Enterobacterales in the PF fluid after DP. CONCLUSION: Enterobacterales and multidrug-resistant bacteria are detected frequently after PD and DP, and are associated with more severe complications and PF in patients undergoing DP.

ANTECEDENTES: La fístula pancreática (pancreatic fistula, PF) es una complicación frecuente de la cirugía pancreática. No está claro cómo los microorganismos que se encuentran en el líquido de la PF (pancreatic fistula fluid, PFF) afectan los resultados y qué microbios están presentes después de la duodenopancreatectomía (pancreaticoduodenectomy, PD) y de la pancreatectomía distal (distal pancreatectomy, DP). El objetivo de este estudio fue comparar el espectro microbiológico del PFF después de PD versus DP y su asociación con las complicaciones postoperatorias. MÉTODOS: Se analizaron las cepas bacterianas y las tasas de resistencia a los antibióticos de las muestras bacterianas obtenidas del PFF de pacientes de nuestra institución que se sometieron a DP o PD. Las bacterias identificadas en los cultivos se clasificaron en "enterobacterias" y "otros microorganismos intestinales y no intestinales" en función de si típicamente forman parte de la flora intestinal humana normal o no. RESULTADOS: Un total de 847 pacientes se sometieron a resección pancreática (PD: 600, DP: 247) entre julio de 2007 y diciembre de 2016, y se detectó FP clínicamente relevante en 131 pacientes (15,5%). Se obtuvieron muestras bacterianas de 108 pacientes (DP n = 47, PD N = 61), de los cuales 19 (18%) eran estériles. Se detectaron enterobacterias en el 74% del PFF después de PD y en el 34% después de DP. El PFF infectado, con flora polimicrobiana o flora multirresistente fue más frecuente después de la PD (95,1%, 50%, 47,5%, respectivamente) que después de la DP (66,0%, 25,8%, 6,4%, respectivamente). Los pacientes con complicaciones de grado superior (Clavien-Dindo 4/5) o PF grado C presentaron más enterobacterias y enterobacterias multirresistentes en el PFF después de DP. CONCLUSIÓN: Las enterobacterias y las bacterias multirresistentes se detectaron con frecuencia después de la PD y la DP, y se asociaron a complicaciones más graves y PF en pacientes sometidos a DP.

Influence of bile contamination for patients who undergo pancreaticoduodenectomy after biliary drainage.

BACKGROUND: The influence of bile contamination on the infectious complications of patients undergoing pancreaticoduodenectomy (PD) has not been thoroughly evaluated. AIM: To evaluate the effect of preoperative biliary drainage and bile contamination on the outcomes of patients who undergo PD. METHODS: The database of 4101 patients who underwent PD was reviewed. Preoperative biliary drainage was performed in 1964 patients (47.9%), and bile contamination was confirmed in 606 patients (14.8%). RESULTS: The incidence of postoperative infectious complications was 37.9% in patients with preoperative biliary drainage and 42.4% in patients with biliary contamination, respectively. Patients with extrahepatic bile duct carcinoma, ampulla of Vater carcinoma, and pancreatic carcinoma had a high frequency of preoperative biliary drainage (82.9%, 54.6%, and 50.8%) and bile contamination (34.3%, 26.2%, and 20.2%). Bile contamination was associated with postoperative pancreatic fistula (POPF) Grade B/C, wound infection, and catheter infection. A multivariate logistic regression analysis revealed that biliary contamination (odds ratio 1.33, P = 0.027) was the independent risk factor for POPF Grade B/C. The three most commonly cultured microorganisms from bile (Enterococcus, Klebsiella, and Enterobacter) were identical to those isolated from organ spaces. CONCLUSION: In patients undergoing PD, bile contamination is related to postoperative infectious complication including POPF Grade B/C. The management of biliary contamination should be standardised for patients who require preoperative biliary drainage for PD, as the main microorganisms are identical in both organ spaces and bile.

Intraoperative Dexamethasone Decreases Infectious Complications After Pancreaticoduodenectomy and is Associated with Long-Term Survival in Pancreatic Cancer.

BACKGROUND: Dexamethasone is administered intraoperatively to prevent anesthesia-related nausea and vomiting and to reduce postoperative opioid administration. However, the adverse effects of corticosteroids on anastomotic healing and wound infection as well as oncologic outcomes remain unclear. We analyzed the effect of intraoperative dexamethasone administration on surgical outcomes after pancreaticoduodenectomy and on long-term survival in pancreatic cancer patients. METHODS: A total of 679 pancreaticoduodenectomies from a prospectively maintained database were analyzed. Surgical outcomes were compared between patients who received intraoperative dexamethasone and those who did not. Kaplan-Meier curves and Cox-regression survival analysis were performed in patients with pancreatic cancer. A propensity analysis was done to reduce the inherent bias of retrospective design. RESULTS: Patients who received dexamethasone (117, 17.2%) were younger and more likely to be female than those who did not (p = 0.001). Overall and 30-day major morbidity were similar among all resected patients, although there were fewer infectious complications in the dexamethasone group (18.8% vs. 28.5%, p = 0.032). In pancreatic cancer patients, dexamethasone was associated with significantly improved median overall survival (46 vs. 22 months, p = 0.017). This effect occurred independently of stage, pathologic characteristics, or adjuvant therapy, with adjusted hazard ratios, derived from pre-propensity and post-propensity analysis, of 0.67 (0.47-0.97) and 0.57 (0.37-0.87), respectively. CONCLUSIONS: A single intraoperative dose of dexamethasone did not increase morbidity after pancreaticoduodenectomy and, in fact, was associated with a decrease in infectious complications. The treatment was independently associated with improved overall survival in patients with pancreatic adenocarcinoma, an effect that cannot be explained and needs further validation in a prospective setting.

Clinical significance of drain fluid culture after pancreaticoduodenectomy.

BACKGROUND: The mechanism of infected postoperative pancreatic fistula (POPF) following pancreaticoduodenectomy (PD) is undefined. Drain amylase has been used to predict POPF, whereas little data are available about the value of drain fluid culture. The aim was to investigate the incidence, risk factors and association with surgical outcomes of positive drainage culture (PDC) after PD. METHODS: A single-center retrospective analysis was conducted of prospectively collected data from patients who underwent PD between January 2005 and December 2015. Drain fluid samples were obtained for microbiological analysis after surgery. Risk factors for PDC were evaluated, and its influence on surgical outcomes was explored. RESULTS: Of 768 patients, 261 (34%) had PDC during the postoperative period. Among them, a total of 434 isolates were yielded. One hundred and seven (24.7%) were Gram-positive, 283 (65.2%) Gram-negative, and 44 (10.1%) fungi. Multivariate analysis revealed that body mass index (BMI) ≥25 kg/m2 , preoperative chemoradiation and intra-operative red blood cell transfusion were independent risk factors for PDC. PDC was associated with higher incidences of complications including POPF, major complications and reoperation, but with no correlation between the day of PDC and complications. BMI ≥25 kg/m2 , early PDC (≤3 days), main pancreatic duct <3 mm, and soft pancreas were revealed as independent predictors for POPF. There was a correlation between type of microorganisms and complications. CONCLUSION: Considering the correlation between PDC and postoperative complications, preventive measures are crucial to improve outcomes after PD. Whether antibiotic treatment for early PDC will alter the clinical course of POPF needs further evaluation.

Postoperative pancreatic fistula: Microbial growth determines outcome.

BACKGROUND: Postoperative pancreatic fistula is a dangerous complication in pancreatic surgery. This study assessed the impact of microbiologic pathogens detected in postoperative pancreatic fistula on clinical outcomes after partial pancreatoduodenectomy and distal pancreatectomy. METHODS: Microorganisms in postoperative pancreatic fistula were identified by microbiologic analyses from abdominal drains or intraoperative swabs during relaparotomy. Demographic, operative, and microbiologic data, as well as postoperative outcomes were examined. RESULTS: Of 2,752 patients undergoing partial pancreatoduodenectomy and distal pancreatectomy, 256 patients with clinically relevant postoperative pancreatic fistula (International Study Group of Pancreatic Surgery [ISGPS] grades B and C) were identified (9.3%) and microbiologic cultures were positive in 210 patients (82.0%), with a higher rate after partial pancreatoduodenectomy (95.8%) than after distal pancreatectomy (64.3%; P < .001). Microbiologic spectra differed distinctively between partial pancreatoduodenectomy and distal pancreatectomy. Detection of microorganisms in postoperative pancreatic fistula resulted in a higher morbidity and mortality, including postpancreatectomy hemorrhage (42.4% vs 21.7%; P = .009), sepsis (38.1% vs 6.5%; P < .001), wound infection (30.0% vs 6.5%; P = .001), reoperation (48.1% vs 10.9%; P < .001), hospital stay (median 42 vs 26 days; P < .001), and overall 90-day mortality (19.5% vs 4.3%; P = .013) and was identified as an independent risk factor for sepsis, wound infection, and reoperation in the multivariate analysis. CONCLUSION: Detection of microorganisms in postoperative pancreatic fistula is frequent after pancreatic resection and indicates a turning point in the development of postoperative pancreatic fistula into a life-threatening condition. Whether early anti-infective therapy in combination with interventional measures or a surgical reintervention are warranted, has yet to be elucidated.

Eikenella corrodens perirenal abscess resulting from a pancreatic fistula in a patient with chronic pancreatitis. Case report and literature review.

We present a case of a right perirenal Eikenella corrodens abscess in a patient with chronic pancreatitis and poor dental hygiene. Endoscopic Retrograde CholangioPancreaticography (ERCP) revealed a pancreatic fistula draining to the right perirenal loge. The patient was treated with broad-spectrum antibiotics, percutaneous drainage and endoscopic stenting of the duct of Wirsung, stopping the supply of the fistula. A full recovery in our patient was observed. Considering the uncommon location of the abscess, a review of the different aetiologies of perirenal abscesses and their distrubution patterns, and the endoscopic treatment of symptomatic pancreatic fistulas seemed worthwhile.

Contaminated drainage fluid and pancreatic fistula after pancreatoduodenectomy: A retrospective study.

BACKGROUND: Appropriate bacterial infection control in the perioperative period of a pancreaticoduodenectomy (PD) is important to prevent and manage serious complications including postoperative pancreatic fistula (POPF). In the present study, the clinical impact of bacterial contamination of intra-abdominal discharge on the rate of POPF after PD was analysed retrospectively. MATERIALS AND METHODS: The data for 82 consecutive patients who had undergone PD at our hospital between January 2009 and July 2014 were retrospectively analysed to review patient characteristics and perioperative and postoperative parameters. We compared the clinicopathologic features between patients with bacterial contamination of drainage fluid and those without bacterial contamination of drainage fluid. We also examined the relationship between POPF and bacterial contamination of drainage fluid, according to the bacterial strain involved. RESULTS: The incidence of Grade B/C POPF was significantly higher in the bacterial contamination positive group than in the bacterial contamination negative group (44.0% vs. 0.0%; p < 0.001). Soft gland texture and bacterial contamination of intra-abdominal discharge were found to be risk factors for POPF (odds ratio: 9.00, 95% confidence interval: 1.17-409.46 and odds ratio: 43.94, 95% confidence interval: 5.72-1992.04, respectively). The incidence of Grade B/C POPF was significantly higher in patients harbouring Pseudomonas aeruginosa than in patients harbouring bacteria other than Pseudomonas aeruginosa (p = 0.005). CONCLUSION: Bacterial contamination of intra-abdominal discharge is a risk factor for the development of pancreatic fistulae. Cases involving contamination with Pseudomonas aeruginosa warrant extreme caution.

The occurrence of Enterococcus faecium and faecalis Is significantly associated With anastomotic leakage After pancreaticoduodenectomy.

BACKGROUND AND AIMS: Enterococcus has emerged as a virulent species; Enterococcus faecium especially has arisen as a source of nosocomial infections. Furthermore, specific Enterococcus faecalis species are significantly associated with anastomotic leakage in rodent studies. The objective of this study was to investigate whether the occurrence of Enterococci ( E. faecium and E. faecalis) obtained from drain samples was associated with leakage in humans undergoing pancreaticoduodenectomy. MATERIALS AND METHODS: All patients undergoing pancreaticoduodenectomy had a peritoneal drain sample sent for culturing between postoperative days 3 and 10. Postoperative pancreatic fistulas were defined and classified according to the International Study Group of Pancreatic Fistula. Bile leakage was radiologically verified. Postoperative complications were classified according to the Dindo-Clavien classification. RESULTS: A total of 70 patients were eligible and enrolled in this study. Anastomosis leakage was observed in 19 patients; 1 leakage corresponding to the hepaticojejunostomy and 18 pancreatic fistulas were identified. In total, 10 patients (53%) with leakage had Enterococci-positive drain samples versus 12 patients (24%) without leakage [odds ratio (OR) = 5.1, 95% confidence interval (CI) = 1.4-19.4, p = 0.02]. Preoperative biliary drainage with either endoscopic stenting or a percutaneous transhepatic cholangiography catheter was associated with the occurrence of Enterococci in drain samples (OR = 5.67, 95% CI = 1.8-12.9, p = 0.003), but preoperative biliary drainage was not associated with leakage (OR = 0.45, 95% CI = 0.1-1.7, p = 0.23). CONCLUSION: Enterococci in drain sample cultures in patients undergoing pancreaticoduodenectomy occurs significantly more among patients with anastomotic leakage compared to patients without leakage.

Abdominal contamination with Candida albicans after pancreaticoduodenectomy is related to hemorrhage associated with pancreatic fistulas.

BACKGROUND/OBJECTIVES: Pancreatic fistulas are one of the most frequent morbidities after pancreaticoduodenectomy. Several reports have suggested a relationship between bacterial infections and postoperative pancreatic fistulas, although details of the mechanisms involved in hemorrhage in association with the fistulas have not been elucidated. This study retrospectively examined the relationship between positive drainage culture and hemorrhage associated with pancreatic fistulas after pancreaticoduodenectomy. METHODS: From January 2012 to December 2015, 142 consecutive patients underwent pancreaticoduodenectomy at our institution. We retrospectively reviewed the patients' demographic data, perioperative laboratory data, and drainage culture results. RESULTS: Twenty-four (17%) patients had clinically relevant postoperative pancreatic fistulas, whereas thirty-four (24%) patients experienced positive drainage culture. Multivariable analysis revealed that positive drainage culture was independently associated with clinically relevant postoperative pancreatic fistulas (odds ratio, 18.1; 95% confidence interval, 5.5-72.2; P < 0.001). Additionally, the prevalence of Candida albicans in the lavage of eight patients significantly correlated with hemorrhage associated with pancreatic fistulas (odds ratio, 43.5; 95% confidence interval, 6.2-513.3; P < 0.001). Seventy-five percent (6/8) of these patients suffered potentially lethal hemorrhagic complications and needed intervention. CONCLUSIONS: A positive abdominal drainage culture is associated with the development of pancreatic fistulas. Moreover, the presence of Candida albicans in drainage fluid may be a risk factor for hemorrhagic complications.

Infection control for prevention of pancreatic fistula after pancreaticoduodenectomy.

BACKGROUND/AIMS: Effectiveness of infection control for prevention of pancreatic fistula (PF) after pancreaticoduodenectomy (PD) is not clear. We analyzed the impact of infection on the development of PF and examined the effect of enhanced infection control to prevent PF. METHODOLOGY: Amylase level (D-amylase) and bacterial culture (D-culture) of drainage fluid were evaluated on POD 1, 3, 5 and 7, in 90 consecutive patients with soft pancreas who underwent PD. The study period was divided into two periods. The relationship between D-amylase and D-culture was examined, and the clinicopathological factors predicting PF were analyzed in the first period. Then, anti-infection measures were introduced in the second period, and the effect of enhanced infection control was examined. RESULTS: Twenty-nine out of 58 patients (50.0%) developed PF in the first period. D-amylase were higher in patients with D-culture infection than in those without it (p<0.05). D-amylase above 10,000IU/L on POD1 and D-culture infection on POD3 were independent predictive factors for PF by multivariate analysis (p<0.01). After introduction of enhanced infection control in the second period, four out of 32 patients (12.5%) developed PF. The rates of PF and D-culture infection were significantly reduced (p<0.05). CONCLUSIONS: Infection of drainage fluid is related to an increased level of amylase, resulting in PF. Enhanced infection control can effectively prevent PF after PD in soft pancreas.

Bacterial contamination in ascitic fluid is associated with the development of clinically relevant pancreatic fistula after pancreatoduodenectomy.

OBJECTIVES: Clinically relevant postoperative pancreatic fistula (POPF) after pancreatoduodenectomy is often accompanied by bacterial infection. To elucidate the mechanism of bacterial infection associated with POPF, we investigated the relationship between POPF and bacteria isolated from ascitic fluid and removed drains. METHODS: Subjects were 101 patients who had undergone pancreatoduodenectomy. Microbial culture was performed using ascitic fluid obtained from drains. We also compared the isolated bacteria from removed drains on postoperative day (POD) 4 and after POD 7. RESULTS: In 23 patients (22.8%), microbial cultures were already positive on POD 1, although purulent discharge was not observed. Among patients with grade B/C POPF, bacteria were detected on POD 1 in 53.8%; these isolated bacteria were the same as those isolated after POPF formation. In contrast, only 7.7% of patients with grade A POPF were positive on POD 1. The number of bacteria isolated from drains removed after POD 7 significantly increased compared with those isolated from drains removed on POD 4. CONCLUSIONS: Bacterial contamination in ascitic fluid may be an initiating event that leads to the development of clinically relevant POPF. Therefore, it is important to perform both the administration of the appropriate antibiotics and early drain removal.

Role of octreotide in the treatment of external pancreatic pure fistulas: a single-institution prospective experience.

INTRODUCTION: Octreotide was studied in the treatment of pure external pancreatic fistulas. METHODS: Eighteen cases (12 males, 6 females) were prospectively observed. Six patients (four after radical surgery for periampullary cancer, one endocrine tumor enucleation and one pancreojejunostomy in chronic pancreatitis) were treated as outpatients with octreotide alone because of low basal fistula output (mean+/-SD: 96.6+/-27.4 cc/24 h). Twelve (five radical surgery for cancer, five surgery for severe pancreatitis, one enucleation and one pancreojejunostomy) were treated as inpatients with octreotide plus total parenteral nutrition because of the high output (mean+/-SD: 448.4+/-248.2 cc/24 h). RESULTS: Ten of the 12 high-output fistulas healed in 27.8+/-27.7 days, whereas all low-output fistulas healed in 12.1+/-6.6 days. CONCLUSION: Octreotide appears useful in the treatment of external pancreatic fistulas. For optimal results to be achieved, there must be no local infection and no mechanical or anatomical obstacles to the free flow of juice.

[Use of cell-surface antigens of Bacteroides thetaiotaomicron in the passive hemagglutination test and in the inhibition of passive hemagglutination]. / Zastosowanie powierzchniowych antygenów Bacteroides thetaiotaomicron w odczynach hemaglutynacji biernej i zahamowania hemaglutynacji biernej.

The antigens were prepared from three B. thetaiotaomicron strains of different origin (NCTC 10582--reference strain, 312/85--isolated from a pancreas fistula drain of a patient, and 9/18--derived from normal human intestinal microflora). Lipopolysaccharides were extracted by the hot phenol-water method and purified by nuclease tretment. Degradation of lipopolysaccharides was achieved by mild acid hydrolysis obtaining polysaccharide (PS) and lipid (LA) fractions. Capsular polysaccharide (CPS) was extracted from the clinical strain 312/85 producing thick capsules. Antibacterial sera were prepared by immunization of rabbits with formolized suspensions of investigated strains. HA and IHA were performed with all antigens and immune sera. Examined cell-surface antigens (LPSs and CPS) were capable of coating formolized sheep erythrocytes. The titres obtained in the passive hemagglutination test in homologous reactions were 160-320. Polysaccharide fractions (PS) prepared by means of mild acid hydrolysis of LPSs were unable to coat formolized sheep red blood cells. The activity of sensitization of sheep erythrocytes was revealed by lipid fractions of LPSs. All preparations were active as inhibitors in the inhibition of passive hemagglutination. The strongest inhibitors in homologous systems were polysaccharide fractions of LPSs and capsular polysaccharide (the concentration of inhuibitor 8-15 micrograms/ml). The results of performed serological tests indicated the antigenic similarity of standard B. thetaiotaomicron strain NCTC 10582 and clinical strain 312/85. The strain 9/18 from normal human intestinal microflora showed distinct antigenicity. High-molecular cell-surface B. thetaiotaomicron antigens containing carbohydrates (LPS and CPS) can be applied in the passive hemagglutination test and in the inhibition of passive hemagglutination.

A novel replicating agent isolated from the human intestinal tract having characteristics shared with Creutzfeldt-Jakob and related agents.

A novel replicating agent (IFDO) was isolated from ileal fluid. Growth occurred in vitro under aerobic and anaerobic conditions, and was faster at 37 degrees C than at room temperature. The doubling time was 15.8 min. Colonies were dark brown in colour and occurred beneath the surface of agar after conventional surface inoculation. Provisional data indicate that the agent may be a normal intestinal commensal. The agent was remarkably resistant to inactivation by steam at 134 degrees C, formaldehyde and glutaraldehyde; it was relatively resistant to ionising radiation, and it was filterable through membranes with a nominal pore diameter of 10 nm. Such properties, with the exception of growth in cell-free medium, are shared by "unconventional agents" such as those of Creutzfeldt-Jakob disease and scrapie. Further comparison of the properties of the intestinal agent and of slow viruses revealed additional shared characteristics, including resistance to proteinase K and trypsin, and inactivation by guanidine thiocyanate, diethyl pyrocarbonate, phenol and sodium hydroxide. The agent differs from that of scrapie in being inactivated by ethidium bromide, zinc nitrate, EDTA, hydroxylamine in the presence Sarkosyl, and, under certain circumstances, by ribonuclease. Broth cultures of the agent contained particles possessing considerable size heterogeneity. The smaller filterable particles were generally more susceptible to inactivation, did not survive autoclaving, and were inactivated by papaya protease and lipase. It is possible that the replicating agent may be formed by crystallisation from constituents of the medium, and not by a biological process. This does not exclude the postulated relationship to slow viruses.