[Effects of rhubarb on intestinal flora and bacterial translocation in rats with sepsis].

OBJECTIVE: To investigate the effects of rhubarb on intestinal flora and bacterial translocation in septic rats. METHODS: One hundred and four Sprague-Dawley (SD) rats were randomly divided into normal control group, burn group, sepsis group, and sepsis with rhubarb treatment group. All the animals except those in the normal control group were given 30% total body surface area (TBSA) III degree burn on their back followed by endotoxin challenge intraperitoneally in a dose of 20 mg/kg 24 hours after the burn injury. The animals were treated with intraperitoneal injection of ceftriaxone 24 hours after the second hit in various groups in a dose of 60 mg/kg, twice a day with a interval of 12 hours. Rhubarb was also given orally with a dose of 50 mg/kg, twice a day with an interval of 12 hours, at the same time. On 1, 3 and 9 days after treatment, intestinal bacilli in colon and the incidence of bacterial translocation in content of large intestine, liver, lung, mesenteric lymph node and blood in each group were determined. RESULTS: Neither intestinal bacilli in colon nor bacterial translocation showed significant change after the burn injury [(5.86+/-0.62) log cfu/g vs. (5.52+/-0.41) log cfu/g]. The second hit with endotoxin obviously increased the number of intestinal bacilli in colon [(8.96+/-0.73) log cfu/g, P<0.01], in which Colibacillus remain the predominant flora. At the same time, the incidence of Colibacillus translocation was also very high. The antibiotic ceftriaxone markedly reduced the number of Colibacillus on the 3rd and 9th day after the therapy [(4.43+/-0.64) log cfu/g, (5.82+/-0.99) log cfu/g, both P<0.01]. However, the number of some opportunistic pathogens, such as Pseudomonas aeruginosa and Baumanii, significantly increased, and they substituted Colibacillus to become the predominant flora in gut. Furthermore, the species of bacterial translocation also switched to Pseudomonas aeruginosa and Baumanii from Colibacillus. Rhubarb could prevent the loss of enteric bacilli in gut [(8.24+/-1.32) log cfu/g]. Moreover, it also extenuated the effects of antibiotics in diminishing commensal flore in gut. Lastly, the rhubarb could inhibit bacterial translocation at the early stage of sepsis (incidence of translocation on 1 th day of the therapy: 40.62% vs. 6.25%, P<0.05). CONCLUSION: Rhubarb can protect the gut microbiogeocoenosis, mitigate the bactericidal effect on antibiotics on commensal flora, and inhibit bacterial translocation at the early stage of sepsis.

Effect of broad-spectrum antibiotics on bacterial translocation in burned or septic rats.

BACKGROUND: Antibiotics are frequently used to treat critically ill patients, and its use is often accompanied by intestinal dysbiosis that might further lead to bacterial translocation (BT). Nevertheless, studies on the relationship between antibiotic therapy and BT are rare. In the present study, we investigated the effect of broad-spectrum antibiotics on BT in an experimental rat model of burn or sepsis injury. METHODS: The septic rat model was simulated by a second insult with lipopolysaccharides after burn injury. Ninety-two male Sprague-Dawley rats were randomly divided into control, burn, and sepsis groups (n = 8 or 9, each group), and the latter two groups were then treated with imipenem or ceftriaxone for 3 or 9 days. The mesenteric lymph nodes, liver, lungs, and blood were collected at each time point under sterile conditions for quantitative bacterial culture and strain identification. The differences between the groups were compared by Fisher exact test or Mann-Whitney U test. RESULTS: Only minimal Escherichia coli translocation to the mesenteric lymph nodes was observed in the normal control group, in which the BT rate was 12.5%. Burn injury did not affect the BT rate (Burn group vs. Control group, 12.5% vs. 12.5%, P = 1.000), whereas the BT rate showed an increased trend after the second insult with lipopolysaccharide (Sepsis group vs. Control group, 44.4% vs. 12.5%, P = 0.294), and many strains of Enterobacteria spp. were detected in distant organs (liver, lung, and blood) [Sepsis group vs. Control group, 0 (0,3) vs. 0 (0,0), U = 20, P = 0.045]. After the antibiotic treatment, BT to the distant organs was increased in burned rats [Burn IT3 group vs. Burn group, 0 (0,2) vs. 0 (0,0); Burn IT9 group vs. Burn group, 0 (0,1) vs. 0 (0,0); Burn CT9 group vs. Burn group, 0 (0,2) vs. 0 (0,0); all U = 20 and P = 0.076] but decreased in septic rats [Sepsis CT3 group vs. Sepsis group, 0 (0,0) vs. 0 (0,3), U = 20, P = 0.045]. The total amount of translocated bacteria, regardless of which antibiotic was used, was increased in burned rats [Burn IT9 group vs. Burn group, 2.389 (0,2.845) vs. 0 (0,2.301) Log10 colony-forming units (CFU)/g, U = 14, P = 0.034; Burn CT3 group vs. Burn group, 2.602 (0,3.633) vs. 0 (0,2.301) Log10 CFU/g, U = 10.5, P = 0.009], but there was a slightly decreased trend in septic rats [Sepsis IT9 group vs. Sepsis group, 2.301 (2,3.146) vs. 0 (0,4.185) Log10 CFU/g, U = 36, P = 0.721; Sepsis CT9 group vs. Sepsis group, 2 (0,3.279) vs. 0 (0,4.185) Log10 CFU/g, U = 32.5, P = 0.760]. Remarkably, the quantity of Enterococci spp. dramatically increased after broad-spectrum antibiotic treatment in both the burned and septic groups [Burn IT3 group vs. Burn group, 1 (0,5.164) vs. 0 (0,0) Log10 CFU/g, U = 16; Burn IT9 group vs. Burn group, 1 (0,2.845) vs. 0 (0,0) Log10 CFU/g, U = 16; Burn CT3 group vs. Burn group, 2.602 (0,3.633) vs. 0 (0,0) Log10 CFU/g, U = 8; Burn CT9 group vs. Burn group, 1 (0,4.326) vs. 0 (0,0) Log10 CFU/g, U = 16; Sepsis IT3 group vs. Sepsis group, 2.477 (0,2.903) vs. 0 (0,0) Log10 CFU/g, U = 4.5; Sepsis IT9 group vs. Sepsis group, 2 (0,3.146) vs. 0 (0,0) Log10 CFU/g, U = 9; Sepsis CT3 group vs. Sepsis group, 1.151 (0,2.477) vs. 0 (0,0) Log10 CFU/g, U = 18; Sepsis CT9 group vs. Sepsis group, 2 (0,3) vs. 0 (0,0) Log10 CFU/g, U = 13.5; all P < 0.05]. CONCLUSIONS: Broad-spectrum antibiotics promote BT in burned rats but prevent BT in septic rats, especially preventing BT to distant organs, such as the liver and lung. Moreover, Enterococci spp. with high drug resistance and high pathogenicity translocated most after antibiotic treatment.

[Influence of broad-spectrum antibiotics on the gut microflora in sepsis in rats].

OBJECTIVE: To study the influence of broad-spectrum antibiotics on intestinal microecology in septic rats. METHODS: Fifty-six Sprague-Dawley (SD) rats were randomly divided into normal control, burn and sepsis group. Rats in the latter two groups received 30% total body surface area (TBSA) III degree burns on back followed by an injection of endotoxin in a dose of 20 mg/kg 24 hours later. The animals in sepsis group were treated with intraperitoneal injection of ceftriaxone 12 hours after the endotoxin challenge in a dose of 60 mg/kg, and it was repeated 12 hours later. Another group of rats received burn injury only. Eight rats in burn group and sepsis group were sacrificed before ceftriaxone treatment, 3 days and 9 days after the treatment, respectively. The gastric, intestinal and colonic contents were collected for bacterial cultures and species determination. RESULTS: The influence of burn injury on the number and species of gut bacteria was not obvious. The addition of endotoxin could markedly increase the number of enteric bacilli in small intestine and colon (both P < 0.01), but not in stomach. However, the number of enteric bacilli was sharply decreased in intestine and colon after ceftriaxone treatment (all P < 0.01). Furthermore, the ratio of cocci to bacilli was seriously inverted in intestine and colon after ceftriaxone treatment, though burn injury followed by endotoxin had dramatically raise the ratio of cocci to bacilli in intestine and colon.It also produce a loss of anaerobic bacteria in colon, though the difference in number was not statistically significant. CONCLUSION: Broad-spectrum antibiotics could decrease the amount of enteric bacilli, making enterococci to be the predominant microbial flora in gut.

[Selective action of broad-spectrum antibiotics on intestinal flora in sepsis in rats].

OBJECTIVE: To investigate the selective effect of broad-spectrum antibiotics on the intestinal flora in sepsis in rats. METHODS: Fifty-six SD rats were randomly divided into normal control group, scald group [before ceftriaxone sodium (rocephin) treatment group], scald group with 3 days of rocephin treatment, scald group with 9 days of rocephin treatment, and sepsis group (before rocephin treatment group), sepsis group with 3 days of rocephin treatment, and sepsis group with 9 days of rocephin treatment. All the animals were incurred with 30% III degree burns on their back followed by endotoxin challenge with a dose of 20 mg/kg 24 hours after the burn injury. The animals were treated with intraperitoneal injection of ceftriaxone 24 hours (60 mg/kg, quaque 12 hours) after the second hit with endotoxin. At the end of the treatment, the bacteria in stomach, intestine and colon were cultured. The number and kind of the bacteria were also determined. RESULTS: Antibiotics significantly increased the number of cocci (P<0.05 or P<0.01). The ratio between cocci and bacilli was markedly inverted. In selective culture of gut bacilli, E.Coli was almost the only bacteria in the contents of stomach, intestine and colon in normal control group, but after burns and endotoxin challenge, Klebsiella pneumoniae, Proteus mirabilis appeared. After the rats received antibiotics treatment, E. coli decreased in number or disappeared, and was replaced mainly by Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, Enterobacter cloacae and Proteus and other bacilli. CONCLUSION: Broad-spectrum antibiotics can induce imbalance of bacteria flora in the gut, resulting in a reversion of the ratio between cocci and bacilli, and also reduction in intestinal colonization resistance. Then, opportunistic pathogens become dominant flora in gut, which may cause antibiotic-related gut-origin diseases.

Impact of imipenem treatment on colonic mycobiota in rats with double-hit sepsis.

BACKGROUND: Broad-spectrum antibiotic administration promotes intestinal colonization of exogenous fungal pathogens in healthy animals and has been recognized as one of the risk factors of invasive fungal infection in clinical settings. It is unclear whether broad-spectrum antibiotic treatment would change the intestinal mycobiota without exogenous fungal challenge in the context of sepsis. METHODS: We established a rat model of double-hit sepsis using burn injury and endotoxin challenge. Rats with burn injury or double-hit sepsis received imipenem treatment for 3 days or 9 days, and their colon contents were sampled for selective fungal culture and isolation counts. RESULTS: Imipenem treatment promoted the overgrowth of the commensal fungus Geotrichum capitatum in rats with burn injury. Imipenem treatment also promoted colon colonization by exogenous fungi in rats with burn injury and double-hit sepsis, including Trichosporon cutaneum, Candida albicans, Candida krusei, and Candida glabrata. A longer duration of imipenem treatment had a stronger impact on colon colonization by exogenous fungi. CONCLUSION: Imipenem treatment facilitates the overgrowth of commensal fungi and colonization by exogenous, potentially pathogenic fungi in the colons of rats with burn injury or double-hit sepsis.