OBJECTIVETo investigate the role of lymphatics in bacterial translocation from intestine of rats with burn.

METHODSEscherichia coli (E. coli) labeled with chloromethylbenzamidodialkylcarbocyanine (CM-DIL) were prepared. Sixty adult male Wistar rats were randomly divided into scald group and sham injury group according to the envelope method, with 30 rats in each group. Rats in both groups were gavaged with 0.5 mL fluid containing CM-DIL-labeled E. coli. Rats in scald group were inflicted with 30% TBSA deep partial-thickness scald (verified by pathological section) and resuscitated with fluid. Rats in sham injury group were sham injured by bathing in 25 degrees C water for 10 s (verified by pathological section) and also received with fluid infusion. Mesenteric lymph node (MLN), liver, mesenteric lymph fluid (MLF), and liver vein blood (LVB) were harvested at post injury hour (PIH) 2, 24, and 72. Bacteria translocation was detected with fluorescent tracing technique and bacteria culture. The endotoxin content in above-mentioned four kinds of specimens was quantitatively determined with chromogenic substrate limulus amebocyte lysate. The carrying capacity of endotoxin in MLF and LVB was calculated. Data were processed with t test or one-way analysis of variance.

RESULTS(1) Living bacteria were in short-stick form, and they were seen moving in single or in doubles or triples in sample fluid. Dead bacteria were in irregular aggregates. Labeled bacteria in small amount were detected in sham injury group, their number peaked at PIH 24. A large amount of labeled bacteria were detected in scald group at PIH 2, which peaked at PIH 24 and decreased at PIH 72. The largest amount of labeled bacteria were found in MLN in scald group as compared to those in the other samples, and the number peaked at PIH 24 [(5872 +/- 1976) x 10(3) CFU/g], which was obviously higher than that [(216 +/- 110) x 10(3) CFU/g, t = 30.129, P = 0.000] in sham injury group. The number of bacteria decreased at PIH 72, but it was still significantly different from that in sham injury group ( t = 4.323, P = 0.000). The number of bacteria in LVB was the smallest. (2) 29 (24.2%) samples out of the 120 samples in sham injury group were positive for bacteria. 72 (60.0%) samples out of the 120 samples in scald group were positive for bacteria. No alive bacterium was detected at any time point in LVB sample in both group; the other three samples were detected with alive bacteria since PIH 2. There were more alive bacteria detected in MLN and liver as compared with the other two kinds of samples in scald group. The amount of bacteria in MLN, liver, and MLF in scald group were higher than those in sham injury group (with t value respectively 4.353, 4.354, 4.965, P values all equal to 0.000). (3) The endotoxin level in each kind of sample at each time point was obviously higher in scald group than that in sham injury group, and it peaked at PIH 2 in liver and MLF. The difference of endotoxin level among 4 kinds of samples in scald group at PIH 2 was statistically significant ( F = 258.47, P = 0.000), and the endotoxin level was higher in liver, MLN, and MLF. They were obviously higher than those in sham injury group (with t value respectively 43.378, 43.123, 22.423, P values all equal to 0.000). The endotoxin level in MLF was 9 times of that in LVB. (4) The carrying capacity of endotoxin in LVB and MLF at each time point in scald group was higher than that in sham injury group.

CONCLUSIONSCM-DIL marked bacteria can reflect the microbial translocation condition. The lymphatic route is an important pathway for bacteria translocation.

Animals ; Bacterial Translocation ; Burns ; microbiology ; Intestinal Mucosa ; microbiology ; Lymph Nodes ; microbiology ; Lymphatic System ; microbiology ; Lymphatic Vessels ; Male ; Rats ; Rats, Wistar

Animals ; Cecum/microbiology* ; Hyperoxia/blood* ; Microbiota ; Rats

OBJECTIVETo reproduce a reliable rat model of burn with infection for the study of prevention and treatment of infected wound.

METHODS(1) Electrical burn producing apparatus equipped with constant temperature (80°C) and pressure (0.5 kg) was used to reproduce burn injury (with area of 4.5 cm(2)) on both sides of the back in 50 SD rats for different duration (4, 6, 8, 10, 12 s), with 10 rats for each burn duration. On post burn day (PBD) 1, gross condition of wounds was observed with naked eyes. Wounds on the left side were used to observe healing time. The wounds on the right side were used for histological observation to determine the depth of injury, and they were classified into superficial and deep partial-thickness injury. (2) Another 36 SD rats were divided into A (inflicted with superficial partial-thickness burn, n = 18) and B (inflicted with deep partial-thickness burn, n = 18) groups according to the random number table. Rats in both groups were treated in accordance with method of preliminary experiment. Immediately after burn, 0.1 mL of liquid containing 1 × 10(9), 1 × 10(7), 1 × 10(5) CFU Pseudomonas aeruginosa (PA) ATCC 27853 was respectively inoculated to the wounds on one side (with 6 rats for each amount), while the wounds on the other side were treated with the same volume of normal saline as control. Inflammatory reaction of wounds was examined with HE staining on post inoculation day (PID) 1. On PID 1, 2, 3, 5, 7, and 14, the number of subeschar bacteria was respectively counted and the bacteria were identified with Gram stain and biochemical reaction. Wound healing time was recorded. Data were processed with t test.

RESULTS(1) Burn for 6, 8 s was respectively identified as injury time resulting in superficial or deep partial-thickness injury according to histological observation and wound healing time. (2) Obvious inflammatory cell infiltration was observed in the wounds in B group which were inoculated with 1 × 10(7), 1 × 10(9) CFU PA, and the infiltration was less marked in A group with inoculation of 1 × 10(9) CFU PA. (3) The bacteria isolated from wounds of A and B groups was identified as PA. The subeschar bacteria count within PID 14 in A group, in which different amount of PA was inoculated, was mostly less than 1 × 10(5) CFU/g of tissue, while that in B group in which 1 × 10(9) CFU PA was inoculated was more than 1 × 10(5) CFU/g of tissue. (4) There was no obvious difference in wound healing time between wounds inoculated with different amount of PA and wounds treated with normal saline in A group (with t value respectively 1.26, 0.29, 1.07, P values all above 0.05). Wound healing time of wounds in B group, in which 1 × 10(9) CFU PA was inoculated, was longer as compared with that treated with normal saline [(22.5 ± 1.0) d vs. (19.4 ± 1.6) d, t = 2.73, P < 0.05].

CONCLUSIONSIn rat, deep partial-thickness burn wound inoculated with 1 × 10(9) CFU PA ATCC 27853 is a reliable model with high reproducibility for the study of infection of burn wound.

Animals ; Burns ; microbiology ; Disease Models, Animal ; Male ; Rats ; Rats, Sprague-Dawley ; Wound Infection ; microbiology

OBJECTIVETo observe the ultrastructural change of the route of gut bacterial translocation in a rat with spinal cord injury (SCI).

METHODSForty Wistar rats were divided into the following groups: control group and 3 SCI groups (10 in each group). The rats in the SCI groups were established SCI model at 24 h, 48 h, and 72 h after SCI. Small intestine mucous membrane tissue was identified and assayed by transmission electron microscope, scanning electron microscope and immunofluorescence microscopy.

RESULTSSmall intestine mucous membrane tissue in control group was not damaged significantly, but those in SCI groups were damaged significantly. Proliferation bacteria in gut lumen attached on microvilli. The extracellular bacteria torn the intestinal barrier and perforated into the small intestinal mucosal epithelial cell. The bacteria and a lot of particles of the seriously damaged region penetrated into the lymphatic system and the blood system directly. Some bacteria were internalized into the goblet cell through the apical granule. Some bacteria and particles perforated into the submucosa of the M cell running the long axis of M cells through the tight junctions. In the microcirculation of mucosa, the bacteria that had already broken through the microvilli into blood circulation swim accompanying with erythrocytes.

CONCLUSIONThe routes of bacterial translocation interact and format a vicious circle. At early step, the transcellular pathway of bacterial translocation is major. Following with the destroyed small intestine mucous, the routes of bacterial translocation through the lymphatic system and the blood system become direct pathways. The goblet cell-dendritic cell and M cell pathway also play an important role in the bacterial translocation.

Animals ; Bacteria ; Bacterial Translocation ; Epithelial Cells ; microbiology ; Goblet Cells ; microbiology ; Intestinal Mucosa ; microbiology ; pathology ; ultrastructure ; Intestine, Small ; microbiology ; pathology ; ultrastructure ; Microvilli ; microbiology ; Rats ; Rats, Wistar ; Spinal Cord Injuries ; microbiology

OBJECTIVESTo investigate the mechanism of the Chinese medicine theory that Fei (Lung) and Dachang (Large Intestine) are exteriorly and interiorly related via synchronous observation on the dynamic changes of the respiratory and intestinal microflora.

METHODSForty specific pathogen free Sprague-Dawley rats were selected and randomly divided into blank (10 rats) and chronic bronchitis model groups (30 rats). The blank group rats were put into the smoke-free environment and the model group rats were put into the smoke environment in order to establish pulmonary disease (chronic bronchitis) model. Then the corresponding changes of the respiratory and intestinal microflflora of the model on 20th, 50th and 70th days were synchronously observed.

RESULTSThe respiratory tract microflflora showed an increase in the total aerobic and Staphylococcus aureus and reduced anaerobic amount signifificantly on 20th day in the respiratory tract microflflora (P<0.05 or 0.01). On 50th day, total aerobic, total anaerobic amount and bififidobacterium signifificantly increased (P<0.05). On 70th day, Staphylococcus aureus reduced and lactobacillus increased signifificantly (P<0.01). The intestinal microflflora showed an increase in the total aerobic, Clostridium perfringens, enterobacter and enterococcus significantly increased on 20th day (P<0.05 or 0.01). Staphylococcus aureus on 50th day increased significantly (P<0.05). Total aerobic and enterococcus increased, total anaerobic and Clostridium perfringens reduced signifificantly on 70th day (P<0.05 or 0.01).

CONCLUSIONThe microecosystem of respiratory tract and intestine of rat model during the pathological process showed a dynamic disorder, indicating an interaction between the lung and large intestine which may be one of the connotations as they exteriorly and interiorly related.

Animals ; Bronchitis, Chronic ; microbiology ; pathology ; Disease Models, Animal ; Gastrointestinal Microbiome ; Intestines ; microbiology ; Lung ; microbiology ; Male ; Rats, Sprague-Dawley ; Time Factors

OBJECTIVETo find out the vector ability and function of Nosopsyllus wualis leizhouensis in the transmitting plague.

METHODSIn T: 19 degrees C +/- 1 degrees C, RH: 85% +/- 5%, data regarding the vector ability as cluster spreading, single flea spreading, single flea transmitting plague to single animal, formative bacterial embolus and infection fleas life-span through experiments was gathered.

RESULTSThe rate of infection on fleas was 94.64%, with 100% transmission rate of colony to spread, and 30% from single flea spreading to single animal. In the experiment of single flea transmission, all of the 388 rattus loseas were bitten by the fleas with bacterial, but only 9 animals were characteristically infected with the transmission potential, vector efficiency, survival potential of embolus, vector index as 0.360, 0.257, 0.868 and 0.223 respectively. The mean survive days of infected flea feed with blood were 17.58 (1 - 58), and the mean survive days of hunger infected flea were 7.25 (1 - 16). Formative bacterial embolus days were 8.80 (2 - 16) and the rate of embolus flea was 78.12%.

CONCLUSIONNosopsyllus wualis leizhouensis could serve as vector and important in the mode of plague transmittion.

Animals ; Female ; Insect Vectors ; microbiology ; Male ; Plague ; transmission ; Rats ; Siphonaptera ; microbiology

Altitude ; Animals ; Bacteria ; classification ; genetics ; Feces ; microbiology ; Gastrointestinal Microbiome ; Hypoxia ; microbiology ; Male ; Rats, Sprague-Dawley

A total of 1,618 ticks [420 individual (adults) and pooled (larvae and nymphs) samples], 369 rodents (Apodemus arius, Rattus norvegicus, Tscherskia triton, Mus musculus, and Myodes regulus), and 34 shrews (Crocidura lasiura) that were collected in northern Gyeonggi-do near the Demilitarized Zone (DMZ) of Korea during 2004-2005, were assayed by PCR for selected zoonotic pathogens. From a total of 420 individual and pooled tick DNA samples, Anaplasma (A.) phagocytophilum (16), A. platys (16), Ehrlichia (E.) chaffeensis (63), Borrelia burgdorferi (16), and Rickettsia spp. (198) were detected using species-specific PCR assays. Out of 403 spleens from rodents and shrews, A. phagocytophilum (20), A. platys (34), E. chaffeensis (127), and Bartonella spp. (24) were detected with species-specific PCR assays. These results suggest that fevers of unknown causes in humans and animals in Korea should be evaluated for infections by these vector-borne microbial pathogens.
Anaplasma phagocytophilum/genetics/isolation & purification ; Animals ; Biological Warfare ; DNA, Bacterial/genetics/isolation & purification ; Ehrlichiosis/transmission/veterinary ; Humans ; Korea ; Mice/*microbiology ; Rats/*microbiology ; Seasons ; Shrews/*microbiology ; Ticks/*microbiology ; Zoonoses

OBJECTIVETo investigate the dynamic variability of intestinal flora and endotoxins in rats with fulminate hepatic failure.

METHODSEstablishing the fulminate hepatic failure models by intraperitoneal injection of Galactosamine. Forty Sprague-Dawley rats were divided into three groups: group A (n=10) were killed at the beginning of the experiment as control; while Group B (n=12) and C (n=18), the fulminate hepatic failure models, were killed 24 and 48 hours respectively after successful induction. Then, the contents of the jejunum, ileum and colon descendents were collected and a quantitative analysis was made about intestinal flora. Meanwhile, the concentrations of endotoxin in portal vein and right ventricle were determined and so were those in contents of ileums and colons.

RESULTSOur experiments showed that the livers of rats in group B were injured most seriously among three groups, and a minor recovery of hepatic function was observed in group C with the decrease of total bile acids (P< 0.05). Analysis on intestinal flora show: the intestinal enterobacteriacea increase and the lactobacillus decrease in group B (P< 0.01 in jejunum and ileum and P<0.05 in colon). The comparisons between group C and B showed that the enterobacteriacea in the former decreased in both jejunum and colon (P< 0.05) while the number of lactobacillus recovered in the jejunum of group C (P<0.05). Quantitative analysis on endotoxins showed that the ileum endotoxin increased in group B (P< 0.05) and in group C, endotoxins in ileum and colons also increased (vs. control, P<0.01); portal endotoxin in group B showed higher level than that in group A and C (P< 0.01).

CONCLUSIONThe alteration of intestinal flora was observed in fulminate hepatic failure rats. Abnormal intestinal flora might lead to incline of endotoxin in ileum, colon and portal vein, while the recovery of normal intestinal flora would decrease the level of portal endotoxin.

Animals ; Bacteria ; isolation & purification ; Endotoxins ; analysis ; Intestines ; chemistry ; microbiology ; Liver ; physiopathology ; Liver Failure ; microbiology ; Male ; Rats ; Rats, Sprague-Dawley

This paper is to explore changes of intestinal mucosal barrier, intestinal flora, and bacterial translocation in rats with severe acute pancreatitis (SAP). Twenty four male SD rats were randomly divided into the control group (n = 10) and the experimental group (n = 14). The model of severe acute pancreatitis of rats was induced by the method of injecting adversely 5% sodium taurocholate into the common biliary-pancreatic duct. All of the rats were killed after 24 hours and the level of the serum amylase and the plasma endotoxin was determined after that. The pathological changes of pancreas and small intestine were observed through hematoxylin-eosin staining (HE staining) and the abdominal viscera bacterial translocation rates were tested. With the method of real-time polymerase chain reaction (RT-PCR) the quantity of the intestinal flora was analyzed. In the control group, the level of Escherichia coli, Lactobacillus and Bifidobacterium were 2.08 ± 1.29, 11.04 ± 7.55 and 12.21 ± 4.95, respectively. On the contrast, the level of Escherichia coli in the cecum contents was much higher (9.72 ± 3.58, P < 0.01), while the Lactobacillus number was decreased significantly (0.67 ± 0.34, P < 0.01), and the Bifidobacterium number was also decreased (4.59 ± 3.42, P < 0.05) in the experimental group, so the ratio of Bifidobacterium/Escherichia coli was reversed. Besides, in the experimental group, the plasma endotoxin positive rates and the bacterial translocation rates were much higher (P < 0.01 or P < 0.05) and the pathology scores of pancreas and small intestines were also significantly higher (P < 0.01) than those in the control group. These results indicated that in severe acute pancreatitis rats, the intestinal mucosal barrier was severely damaged and the dysbacteriosis occurs in the intestinal canal. And these might relate to the occurrence and development of multiple organ infection.
Animals ; Bacterial Translocation ; Endotoxins ; Intestinal Mucosa ; pathology ; Intestines ; microbiology ; Male ; Pancreas ; pathology ; Pancreatitis ; microbiology ; pathology ; Rats ; Rats, Sprague-Dawley