Influence of rectal washout on bacterial counts in the rectal stump

Forty-three patients undergoing a restorative colorectal resection were randomized to have their rectal stump washed out with either 0.9 per cent saline, 2.5 per cent povidone-iodine or 0.3 per cent sodium hypochlorite. The bacterial counts before and after washout for Escherichia coli and Bacteroides fragilis were compared using the Mann-Whitney U test. There was no significant difference in the counts for E. coli before and after washout with saline (log 9.7-log 9.7 organisms/ml) and saline had no influence on the counts of B. fragilis (log 7.9-log 6.5 organisms/ml). Hypochlorite was associated with a significant reduction in E. coli counts (log 6.1-log 1.1 organisms/ml, P less than 0.005) and the counts of B. fragilis (log 8.1-log 0.0 organisms/ml, P less than 0.005). The counts of B. fragilis were significantly reduced by povidone-iodine (log 8.1-log 1.1 organisms/ml, P less than 0.005) but there was no significant reduction in counts of E. coli (log 5.6-log 5.3 organisms/ml). The data suggest that sodium hypochlorite is better than povidone-iodine or saline as a rectal washout for colorectal anastomosis.     

Hemorrhagic shock induces bacterial translocation from the gut

Sepsis and multiple organ failure are common after hemorrhagic shock. The goal of the current experiments was to determine whether hemorrhagic shock would promote the translocation of bacteria from the gut to visceral organs. Twenty-four hours after being subjected to sham shock, or 30, 60, or 90 minutes of shock (30 mm Hg), rats were sacrificed and their organs quantitatively cultured for translocating bacteria. There was a direct relationship between the duration of hemorrhagic shock and the 24-hour mortality rate (p = 0.02). Bacteria did not translocate from the gut in the sham-shock rats, but did translocate to the mesenteric lymph nodes, livers, and spleens of the rats subjected to hemorrhagic shock (p less than 0.01). Rats subjected to 90 minutes of shock shock exhibited a greater degree of bacterial translocation than rats receiving 30 or 60 minutes of shock (p less than 0.05). The most common translocating bacteria were Escherichia coli and Enterococcus. Hemorrhagic shock injured the gut mucosa and caused subepithelial edema and focal areas of necrosis. Thus hemorrhagic shock followed by reinfusion of shed blood disrupts the gut barrier and allows indigenous bacteria normally contained within the gut to cause systemic infections.     

Obstructive jaundice promotes bacterial translocation from the gut

Experiments were performed to determine if obstructive jaundice promotes the translocation of bacteria from the gastrointestinal tract to visceral organs. Three groups of mice were studied: control (n = 20), sham ligated (n = 28), and bile duct ligated (n = 33). The sham-ligated group underwent laparotomy and manipulation of the portal region, whereas the ligated group had their common bile ducts ligated. Seven days later, the mice were killed, their organs cultured, and the gastrointestinal tract examined histologically. The bilirubin levels of the ligated group (18.7 mg/dL) were elevated compared with the other groups (0.5 mg/dL) (p less than 0.05). The incidence of bacterial translocation was higher in the ligated (33%) than in the control (5%) or sham-ligated (7%) groups (p less than 0.05). Since bile is important in binding endotoxin and maintaining a normal intestinal microflora, cecal bacterial populations were quantitated. The cecal levels of gram-negative, enteric bacilli were 100-fold higher in the bile duct-ligated mice in which bacterial translocation occurred (p less than 0.05), indicating that intestinal bacterial overgrowth was a major factor responsible for bacterial translocation. The mucosal appearance of the intestines from the control and sham-ligated groups was normal. In contrast, subepithelial edema involving the ileal villi was present in the ligated group. In conclusion, the absence of bile within the gastrointestinal tract allows intestinal overgrowth with enteric bacilli and the combination of bacterial overgrowth and mucosal injury appears to promote bacterial translocation.     

Total parenteral nutrition promotes bacterial translocation from the gut

Bacterial translocation from the gut may be the primary event in many disease processes. The purpose of this study was to examine the route of nutrient administration on bacterial translocation from the gut. Each of 90 female Fischer rats underwent placement of a central venous catheter and was randomized to one of three groups. Group I (control) received food and water ad libitum. Group II received standard TPN solution orally from a bottle sipper and drank the solution ad libitum. Group III underwent TPN via the central catheter by pair feeding of the animals with group II. Animals were fed for 2 weeks, and liver, spleen, mesenteric lymph nodes, blood, and cecum were aseptically obtained for culture. A statistically significant difference (p less than 0.014) was found between translocation rates of parenterally fed animals compared with enterally fed animals. Two thirds of the animals (18/27) fed parenterally had culture-positive mesenteric lymph nodes compared with one third (9/27) of the enterally fed group and none (0/30) of the control group. A statistically significant increase in the cecal bacterial count was demonstrated in the animals fed the TPN solution, independent of route. Parenteral nutrition promotes bacterial translocation from the gut by increasing the cecal bacterial count and impairing intestinal defense.     

Food without fiber promotes bacterial translocation from the gut

To determine whether the route and/or composition of nutritional support alters intestinal barrier function (measured as bacterial translocation), rats were divided into three groups: food (controls), intravenous total parenteral nutrition (IV-TPN) fed, and oral total parenteral nutrition (ORAL-TPN) fed. Bacterial translocation did not occur in the rats that were fed normally, but did occur in 60% of the rats fed the IV-TPN or the ORAL-TPN diets for 7 days (p less than 0.05). Since both the IV-TPN and ORAL-TPN diets induced bacterial translocation and the TPN solution (28% glucose and 4.5% amino acids) lacks fiber, two additional groups of rats were fed orally 2.5 gm cellulose powder/day plus TPN solution by either the intravenous or the oral route. The addition of cellulose powder decreased the incidence of bacterial translocation to 8% in the group fed the ORAL-TPN diet and to 0% in the group fed the IV-TPN diet. Cellulose improved intestinal barrier function, even though it did not prevent bacterial overgrowth or the loss of mucosal mass in the rats fed the IV-TPN or ORAL-TPN diets. Cellulose powder appears to have prevented bacterial translocation primarily by preventing IV-TPN- or ORAL-TPN-induced alterations in mucosal structure. Thus the oral administration of this fiber maintains intestinal barrier function and prevents bacterial translocation even in the absence of oral nutrients.     

创伤及休克肠道细菌移位的研究

研究创伤失血性休克肠道细菌移位的发生率。设计兔创伤失血性休克试验模型，实验组３０只兔，腹部皮肤撕脱１００ｍｍ×９０ｍｍ，并行股动脉放血致休克，对照组１０只兔，腹部撕脱同实验组，不放血致休克。对照组术后１小时、３小时、５小时取标本均未发现肠道细菌移位，实验组术后１小时采标本已有肠道细菌移位，３小时、５小时组细菌移位达３０％。认为创伤失血性休克早期即有肠道细菌移位，并讨论了其临床意义     

Effect of stress and trauma on bacterial translocation from the gut

Previously, we established that bacteria contained within the gut can cross the GI mucosal barrier and spread systemically, a process termed bacterial translocation. Three models were used to extend this work: cold exposure (up to 16 hr at 4 degrees C), a nontissue injury stress model; femoral fracture-amputation, a trauma model; and thermal injury (30% third-degree burn), a trauma model with retained necrotic tissue. CD-1 mice either with a normal GI microflora or who were monoassociated with Escherichia coli C-25 were subjected to sham or actual stress or trauma. The animals were sacrificed at various times postinsult and the ceca, mesenteric lymph nodes (MLN), spleens, and livers were quantitatively cultured. Neither the incidence nor the magnitude of bacterial translocation was increased in the cold-exposed animals compared to control mice. The incidence of bacterial translocation to the systemic organs was higher in the animals with a normal flora receiving femoral fracture amputation (11%) (P less than 0.02) than in animals receiving a thermal injury (1%) or sham-injured control mice (0%). In contrast, the incidence of translocation to the liver or spleen was higher in burned mice monoassociated with E. coli C-25 (60%) (P less than 0.01) than in E. coli monoassociated mice sustaining femoral fracture amputation (17%). Stress alone (cold exposure) does not promote bacterial translocation; however, trauma, especially in combination with retained necrotic tissue, promotes bacterial translocation. Thus bacteria colonizing the gut can invade systemic organs after trauma, especially when the normal ecology of the gut flora has been disrupted.     

Management of civilian extraperitoneal rectal injuries

OBJECTIVE: The mortality and morbidity of rectal injuries are highly unsatisfactory. We retrospectively reviewed our experience with rectal injuries to draw some practical guidelines for management of such injuries. METHODS: The medical records of all patients diagnosed at our hospitals with full-thickness rectal injuries between 1994 and 2003 were retrospectively reviewed. RESULTS: Full-thickness rectal injuries were identified in 23 patients; 19 patients had extraperitoneal injuries and four had both intra- and extraperitoneal injuries. The mean age was 33.5 years (range, 5-73 years). The mechanism of injury was penetrating in 11 patients, blunt in six, impalement in three and iatrogenic in three. Injuries were closed primarily in 17 patients, with variable combinations of adjunct procedures. Eight patients were treated without colostomy. Drainage and rectal washout were performed in 11 and six patients, respectively. Overall, 11 patients developed complications, including eight wound infections and five pelvic septic complications related to the rectal injury. Four of the five pelvic septic complications and all three deaths occurred in patients with shock, at least two associated-organ injuries and more than 6 hours' delay in treatment. CONCLUSION: Rectal injuries are serious additive mortality and morbidity factors in multi-injured patients. Regardless of treatment modality, wound infection is associated with shock at presentation and more than 6 hours' delay in treatment.     

低位直肠癌保肛手术中直肠冲洗治疗对预后的影响

目的研究低位直肠癌保肛术中应用直肠冲洗对预后的影响。方法随机选择98例低位直肠癌患者分为冲洗组（A组）和单纯手术组（B组）,各49例。在经腹低位直肠前切除中,A组进行远端直肠冲洗并将冲洗液进行细胞学检查。将两组2年局部复发率和1、3、5年生存率进行比较。结果A组有27例找到癌细胞,术后局部复发率为1413％,B组为30．6％,两组比较差异有统计学意义（P〈0．05）;A组术后1、3、5年生存率分别为96．8％、72．3％、52．3％,B组分别为95．7％、65．4％、43．0％,两组术后3、5年生存率比较,差异有统计学意义（P〈0．05）。结论低位直肠癌保肛术中远端直肠冲洗是必要的,可以提高低位直肠癌的治疗效果。     

Acidification of formula reduces bacterial translocation and gut colonization in a neonatal rabbit model

BACKGROUND/PURPOSE: The authors hypothesized that gastric acidity is protective because it is bactericidal. They tested acidified formula for protection against gut colonization and bacterial translocation. METHODS: In vitro: Formula was acidified to pH of 2, 3, 4, 5 and innoculated with Enterobacter. Growth over time was quantitatively assessed. In vivo: 442 premature rabbit pups were sorted randomly and fed formula of pH 2, 3, 4, or 7, with ranitidine. Two models were utilized: (1) with bacterial challenge using a known acid sensitive organism, (2) without bacterial challenge to simulate natural gut colonization and to test against organisms of unknown acid sensitivity. Normal acid animals received pH 7 formula, no ranitidine. On day 3, the mesenteric lymph nodes (MLN), spleen, liver, and cecum were harvested and cultured. RESULTS: Bacterial growth was inhibited at pH 2 and 3, growth was logarithmic above pH 4 (P<.001). Total and organ-specific translocation was reduced at pH 3 and below in both models (P<.05). Translocation with formula pH 3 equaled normal acid animals. Quantitative cecal colonization was reduced in pups receiving pH 3 and below in both models (P<.05). CONCLUSION: Acidification of formula below pH 4 is bactericidal to enteric organisms. Acidified formula decreases bacterial translocation and gut colonization.     

Endotoxin but not malnutrition promotes bacterial translocation of the gut flora in burned mice

Previously we have shown that under certain conditions, bacteria can pass through the intact epithelial mucosa to the mesenteric lymph nodes (MLN), liver, spleen, and bloodstream to cause infection, a process termed bacterial translocation. To extend these studies, we determined the influence of protein malnutrition and endotoxemia on bacterial translocation in burned (25% TBSA) and unburned mice. The results of these experiments documented that protein malnutrition did not promote bacterial translocation from the gut in either burned or unburned animals, although it did disrupt the normal indigenous gut flora. In contrast, a nonlethal dose of endotoxin (IP) promoted bacterial translocation to the mesenteric lymph nodes in burned and unburned mice, but only in burned mice did the bacteria translocate from the gut to other systemic organs (p less than 0.01). Furthermore, the mortality rate of mice receiving only endotoxin or burn was less than 10%, while the combination of endotoxin plus a thermal injury increased the mortality rate to 100% (p less than 0.01). These studies support the concept that bacteria may translocate from the gut to other organs and be a potential source of lethal infections after thermal injury.     

The effect of surgical trauma on the bacterial translocation from the gut.

Bacterial translocation is the passage of viable bacteria from the lumen of the gastrointestinal tract through the intestinal mucosa to other sites. It is believed that bacterial translocation may lead to infection and septicemia. The purpose of this study was to determine what factors in experimental surgical trauma lead to bacterial translocation. Two-month-old Wistar albino rats were divided into five groups: (A) control; (B) anesthesia (ether inhalation); (C) anesthesia and surgery (median laparotomy and transient compression of the intestines); (D) fasting only; and (E) anesthesia, surgery, and fasting. After 48 hours, ileum, mesenteric lymph nodes, and blood were cultured for aerobic and anaerobic organisms. In each group the number of animals with bacteria overgrowth was calculated. The incidence of bacterial translocation to mesenteric lymph nodes and blood in groups B and D were similar to the controls (P greater than .01). There was a significant increase in the number of animals with bacterial translocation in groups C and E (P less than .001). The majority of translocating bacteria were E coli.     

直肠癌前切除术中直肠冲洗对预后的影响分析

目的 分析术中直肠冲洗对直肠癌前切除术患者预后的影响.方法 分析2006年5月至2007年11月中国医学科学院肿瘤医院腹部外科手术的144例直肠癌根治性前切除术患者的临床资料.将144例分为两组,术中直肠冲洗组69例,同期未冲洗组75例,比较两组患者的术后局部复发率及术后5年无瘤生存率.应用SPSS 13.0进行统计学分析,计数资料比较采用x2检验,计量资料采用t检验,Kaplan-Meier法计算术后生存率.结果 直肠冲洗组有55例在冲洗液中找到脱落癌细胞,阳性率达79.7％;直肠冲洗组术后局部复发率为4.6％,未冲洗组为6.7％(x2=0.368,P=0.721);两组患者术后5年无瘤生存率分别为79.7％和74.7％ (x2 =0.517,P=0.553).结论 直肠癌前切除术中,直肠腔内脱落癌细胞的阳性率高,直肠冲洗能够有效清除脱落的癌细胞,可能降低局部复发率并提高远期生存率.     

大鼠脊髓损伤致截瘫后肠道细菌移位的实验研究

目的：探讨大鼠脊髓损伤致截瘫后是否发生肠道细菌移位。方法：建立大鼠脊髓损伤性截瘫模型，以脊髓损伤性截瘫后12h、24h、48h大白鼠为实验组，未损伤脊髓的正常大白鼠为对照组。在无菌条件下，采集动物下腔静脉血进行内毒素定量测定和细菌培养，采集肝、脾、肠系膜淋巴结、肠腔内容物作细菌培养并进行菌种鉴定。取实验组和对照组各动物的肝、脾、肠系膜淋巴结、空肠、回肠进行病理切片HE染色检查，取空、回肠进行电镜检查。结果：大鼠脊髓损伤致截瘫后24h开始出现内毒素血症，截瘫后48h出现细菌移位。结论：大鼠脊髓损伤致截瘫后将发生肠道细菌移位，提示脊髓损伤截瘫的病人应尽早给予抗生素治疗。     

早期肠内营养对肝移植术后肠屏障及细菌移位的影响

目的探讨早期肠内营养对肝移植术后病人肠屏障功能和细菌移位的影响。方法40名肝移植病人被随机分成早期肠内营养（EN）组、胃肠外营养（PN）组。术前、术后第1天及术后第8天检测血浆内毒素水平、D-乳酸水平及二胺氧化酶（DAO）水平，术前及术后第1～7天每日行外周血细菌聚合酶链反应（PCR）检测及血细菌培养。结果（1）术后第8天EN组内毒素、D-乳酸及DAO水平显著低于PN组（P〈0．01）。（2）术后第1天两组内毒素、D-乳酸及DAO水平显著高于术前（P〈0．05），两组之间无统计学差异。术后第8天EN组内毒素、D-乳酸及DAO水平显著低于术后第1天水平（P〈0．05），低于术前水平（P〈0．05）。PN组内毒素、D-乳酸及DAO水平显著高于术前水平（P〈0．05），和术后第1天水平无统计学差异（P〉0．05）。（3）40例肝移植病人PCR检测外周血细菌DNA片段阳性总数为25例，阳性率62．5％，术后第4天起两组有显著差异。（4）PCR大肠杆菌检出占所有细菌检出的60％。（5）40名肝移植病人27例出现全身炎症反应综合征（SIRS），其中EN组12例，PN组15例，PCR阳性组SIRS发生率为96％，PCR阴性组SIRS发生率为20％，SIRS发生组PCR阳性率为88．89％，SIRS阴性组PCR阳性率为7．69％。（6）术后血细菌培养阳性率27．5％，显著低于PCR的62．5％（P〈0．01）；培养阳性者，PCR均呈阳性。（7）PCR阳性组感染并发症发生率为64％（16／25），阴性组均未发生感染（0／15），二者差异有显著性（P〈0．01）。结论肝移植术后施行早期肠内营养能有效的维护肠黏膜屏障功能、防止细菌及内毒素移位，减少术后感染的发生。     

Rapid bacterial screening in the treatment of civilian wounds

A rapid quantitative bacterial screening technique was evaluated in acute traumatic wounds treated in a civilian emergency room. In 80 wounds, the infection rate was 9%. The factors found to have the greatest bearing on the development of infection were the number of bacteria in the wound and the time between wounding and repair. All wound infections occurred in wounds which contained > 10⁵ organisms per gram of tissue. The rapid screening technique was accurate in predicting the critical number of bacteria in 95% of the cases. It is suggested that this quantitative bacteriological screening be used in patients presenting for treatment with wounds over 3 hr old.