Enterotoxigenic Escherichia coli (ETEC) causes neonatal and post-weaning diarrhea in pigs. In order to determine the risk factors, rectal/fecal swabs and visceral organs obtained from pig farms in two regions of South Africa were analyzed microbiologically against risk variables. Seventy-two percent of young pigs were found to be positive for ETEC toxin genes; estB (38.9%), estB/STAP (25%), and estB/LT (13.9%) were dominant. Risk factors for ETEC-diarrhea in pigs include: leaving sick piglets in a pen with healthy piglets [odds ratio (OR) = 33.52; P < 0.0001]; water spillage in pen (OR = 42.87; P < 0.0001); hypothermic piglets (OR = 7.29; P < 0.0001); runt piglets in pen with healthy littermates (OR = 3.65; P < 0.0001); and prolonged use of antibiotics (OR = 3.05; P = 0.05).
Animals ; Animals, Newborn ; Diarrhea ; epidemiology ; microbiology ; Escherichia coli ; genetics ; isolation & purification ; Escherichia coli Infections ; epidemiology ; microbiology ; veterinary ; Genes, Bacterial ; Prevalence ; Rectum ; microbiology ; Risk Factors ; South Africa ; Swine ; Swine Diseases ; epidemiology ; microbiology ; Weaning

OBJECTIVETo investigate the inhibitory effect of Lactobacillus rhamnosus GG ( LGG) against Cronobacter-induced meningitis in neonatal rats.

METHODSThe cell adhesion and invasion capacities of Cronobacter were assayed in Caco-2 cells, and the optimal time length and concentration of the bacterium for infection were determined. The suppressive effects of LGG on the adhesion and invasion of Cronobacter in caco-2 cells were tested by competitive and exclusion experiments, and its inhibitory effect against Cronobacter-induced meningitis was evaluated in neonatal rats.

RESULTSCronobacter showed aggressive adhesion to caco-2 cells with an optimal infection time of 3 h. LGG produced a concentration-dependent inhibition of Cronobacter adhesion and invasion by competing with and excluding the latter for cell adhesion. In neonatal rats, LGG showed an obvious preventive effect and also a moderate therapeutic effect against Cronobacter-induced meningitis.

CONCLUSIONLGG can inhibit Cronobacter entry across the intestinal barrier to achieve preventive and therapeutic effects against Cronobacter-induced meningitis.

Animals ; Animals, Newborn ; Bacterial Adhesion ; Caco-2 Cells ; Cronobacter ; pathogenicity ; Enterobacteriaceae Infections ; therapy ; Humans ; Intestines ; microbiology ; Lactobacillus rhamnosus ; Meningitis, Bacterial ; therapy ; Probiotics ; Rats

OBJECTIVETo investigate MUC2 expression in rat colons induced by probiotics and its effects on the inhibition of E.coli K1 (E44) penetration of the intestinal barrier by probiotics.

METHODSSD rats were subjected to intragastric administration of probiotics, E44, or probiotics +E44 on a daily basis for 7 days, and MUC2 expression in the colons was determined by RT-PCR. MUC2-targeted shRNA (shRNA MUC2) and scrambled shRNA plasmids (shRNA NC) were respectively transfected into Lovo cells, and the efficiency of MUC2 knockdown was determined using qRT-PCR. Competitive exclusion assay was used to evaluate the effects of the probiotics against E44 adhesion and invasion.

RESULTSIntestinal MUC2 mRNA expression was up-regulated in the rats after intragastric administration of probiotics, while E44 administration caused significantly lowered MUC2 expression. MUC2 expression was down-regulated (by 66.7%) by transfection with shRNA MUC2 in Lovo cells as compared with the negative control and mock control cells. The inhibition of E44 adherence and invasion by probiotics was significantly attenuated in transfected Lovo cell culture (in which the relative adhesion and invasion rates of E44 were 56.64% and 66.64%, respectively) as compared with those in the control group.

CONCLUSIONThe up-regulation of MUC2 in rat colons can be one of the mechanisms of the probiotics in antagonizing the translocation of the pathogenic bacteria. Silencing MUC2 expression causes attenuated inhibitory effect of the probiotics on E. coli K1 penetration across human intestinal epithelial cells.

Animals ; Animals, Newborn ; Cell Line, Tumor ; Colon ; drug effects ; metabolism ; microbiology ; Escherichia coli ; pathogenicity ; Escherichia coli Infections ; genetics ; Female ; Gene Expression Regulation, Neoplastic ; Gene Silencing ; Humans ; Mucin-2 ; genetics ; Probiotics ; pharmacology ; RNA, Messenger ; genetics ; RNA, Small Interfering ; Rats ; Rats, Sprague-Dawley ; Transfection

The purpose of this study was to evaluate the capacity of a lactic acid bacteria (LAB) inoculum to protect calves with or without lactose supplements against Salmonella Dublin infection by evaluating histopathological lesions and pathogen translocation. Fifteen calves were divided into three groups [control group (C-G), a group inoculated with LAB (LAB-G), and a group inoculated with LAB and given lactose supplements (L-LAB-G)] with five, six, and four animals, respectively. The inoculum, composed of Lactobacillus (L.) casei DSPV 318T, L. salivarius DSPV 315T, and Pediococcus acidilactici DSPV 006T, was administered with milk replacer. The LAB-G and L-LAB-G received a daily dose of 109 CFU/kg body weight of each strain throughout the experiment. Lactose was provided to the L-LAB-G in doses of 100 g/day. Salmonella Dublin (2 x 1010 CFU) was orally administered to all animals on day 11 of the experiment. The microscopic lesion index values in target organs were 83%, 70%, and 64.3% (p < 0.05) for the C-G, LAB-G, and L-LAB-G, respectively. Administration of the probiotic inoculum was not fully effective against infection caused by Salmonella. Although probiotic treatment was unable to delay the arrival of pathogen to target organs, it was evident that the inoculum altered the response of animals against pathogen infection.
Administration, Oral ; Animals ; Animals, Newborn ; Cattle ; Cattle Diseases/*drug therapy/microbiology/pathology ; Dietary Supplements/*analysis ; Feces/microbiology ; Lactobacillus/metabolism ; Lactose/*metabolism ; Male ; Pediococcus/metabolism ; Probiotics/*therapeutic use ; Salmonella Infections, Animal/*drug therapy/microbiology/pathology ; Salmonella enterica/*drug effects/growth & development ; Tissue Distribution

OBJECTIVETo identify epidemic status of murine typhus in Hongta areas of Yuxi city and to provide evidence for control and prevention of the disease.

METHODSSerologic survey was conducted among residents and rodents. Isolation of Rickettsia moseri was performed.

RESULTSThe overall infection rate among general population was 28.92% (96/332) with geometric meantiter (GMT) as 10.83 and there was no difference between males and females (26.71%, 43/161 vs. 30.99%, 53/171, P > 0.05). Significant differences were found between age groups (P < 0.05) with positive rates of 29.63% (8/27), 18.06% (13/72), 39.62% (42/106), 27.50% (22/80) and 23.40% (11/47) among age groups 0-6, 7-18, 19-39, 40-59 and over 60, respectively. The overall rate of infection in mouse was 44.95% (89/198) with GMT as 30.30. Five isolates of R. moseri from mouse specimen, three from fleas plus one case of murine typhus were diagnosed. Rattus norvegicus and Rattus flavipectus were the predominant species of rodent animals (99.49%, 197/198) and Xenopsylla cheopis was the major species of vector (74.26%, 303/408). Flea index and mouse density were 2.06 and 11.13% respectively.

CONCLUSIONHigh infection rates on R. moseri were demonstrated in rodents and residents as well as high risk of murine typhus outbreak might occur in these areas.

Adolescent ; Adult ; Animals ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Mice ; Middle Aged ; Rats ; Rodent Diseases ; epidemiology ; microbiology ; transmission ; Siphonaptera ; microbiology ; Typhus, Endemic Flea-Borne ; epidemiology ; microbiology ; transmission ; Young Adult

OBJECTIVEScrub typhus is an infectious disease due to Orientia tsutsugamushi transmitted by infected chigger mites. Scrub typhus has long been recognized to occur in southern areas of China, but has recently been increasingly often reported from the north since the first case was reported in Mengyin County, Shandong Province in 1986. The key objectives of the present study were to investigate the clinical manifestations and epidemic factors of scrub typhus in children from the northern new natural foci.

METHODSThe case records of 56 children with scrub typhus who were admitted to the 5 hospitals of Fei County from September 1993 to January 2004 were reviewed. Orientia tsutsugamushi (Ot) was isolated from the cases. Based on ecological observations on the composition, seasonal fluctuation of animal hosts and chigger mites, Ot was isolated from rodents and chiggers. IgG antibodies to Ot was detected by IFA. Genotypes of the Ot isolates were also identified by nested PCR.

RESULTSAmong 56 children scrub typhus cases, 46 were male, 10 were female; 96% exhibited typical eschars or ulcers, 100% cases had high fever, skin rashes were observed in 55 cases (98%), and regional lymphadenopathy occurred in 48 cases (86%). All cases came from countryside, and all had histories of exposure to the crop field. fifty-one serum samples of suspected patients with scrub typhus were collected, 48 were positive for antibodies to Ot. The serotypes were Gilliam types. The cases only appeared in September to December with the peak at mid and late October. Leptotrombidium (L.) scutellare was the most important vector causing scrub typhus in the foci. Apodemus (A.) agrarius was the main host animals of Ot in the crop field. Totally 26 strains were isolated from patients, rodents, and chigger mites. The serotypes of 24 out of the 26 isolates were Gilliam types, while the genotypes of these isolates were Kawasaki types. The serotypes of the other 2 isolates were identical and both were Karp types.

CONCLUSIONChildren scrub typhus patients were frequently seen in the new natural foci of Shandong province. Exposure history, typical eschars or ulcers, and presence of IgG antibody were the important indexes to diagnose the disease.

Adolescent ; Animals ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Mice ; parasitology ; Orientia tsutsugamushi ; isolation & purification ; Scrub Typhus ; epidemiology ; Seasons ; Trombiculidae ; microbiology

A pair primer was designed by Oligo 6.0 according to the pilA gene sequence of E. coli isolated from human in GenBank. The pilA Gene was obtained by PCR with the enteropathogenic E. coli isolated from ducks as template and cloned into pMD18-T vector. It was identified by PCR, restriction endonuclease analysis, DNA sequencing and then subcloned into BamH I/Hind III site of prokaryotic expression vector pET-32a(+) and recombinant expression plasmid pET-32a-pilA was constructed successfully. The plasmid was transformed into Eschericha coli BL21 (DE3) and 36kD pilA recombinant protein was expressed be induced with IPTG. The protein was purified by Ni-agarose affinity chromatograghy and was prepared as vaccine with Freund' s adjuvant. The ducklings were immunized with the vaccine at 1 and 8-day-old respectively. Two weeks after last immunized, the antibody titer of duck serum was detected by ELISA and the ducklings were challenged with 10(9) PFU enteropathogenic E. coli GH1.2 virulent strain. The immunoprotection effect of pilA recombinant protein vaccine was evaluated according to the mortality, re-isolated rate of E. coli, and grades of pathological changes. The results show that the antibody titer are 1:12800, but 1:200 were detected from ducklings immunized with homologous whole cells E. coli inactivated vaccine. The mortality, re-isolated rate of E. coli, degree of pathological changes of immunized ducklings is lower than that of the control ducklings and showed significant or extremely significant differences (P < 0.01 or P < 0.05), but non-significant difference compared to the ducklings which immunized with homologous whole cells E. coli inactivated vaccine (P > 0.05). The results show that pilA recombinant protein has some immunoprotection effect with the challenging of virulent strains of E. coli GH1.2.
Animals ; Animals, Newborn ; Antibodies, Bacterial ; blood ; immunology ; Ducks ; microbiology ; Electrophoresis, Polyacrylamide Gel ; Enteropathogenic Escherichia coli ; genetics ; immunology ; pathogenicity ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli Proteins ; genetics ; immunology ; metabolism ; Fimbriae Proteins ; genetics ; immunology ; metabolism ; Humans ; Immunization ; Polymerase Chain Reaction ; Poultry Diseases ; immunology ; mortality ; prevention & control ; Recombinant Proteins ; administration & dosage ; immunology ; metabolism ; Survival Rate ; Virulence

Escherichia coli (E. coli) strains were collected from young diarrheic calves in farms and field. Strains that expressed the K99 (F5) antigen were identified by agglutination tests using reference antibodies to K99 antigen and electron microscopy. The K99 antigen from a selected field strain (SAR-14) was heat-extracted and fractionated on a Sepharose CL-4B column. Further purification was carried out by sodium deoxycholate treatment and/or ion-exchange chromatography. Monoclonal antibodies to purified K99 antigen were produced by the hybridoma technique, and a specific clone, NEK99-5.6.12, was selected for propagation in tissue culture. The antibodies, thus obtained, were affinity-purified, characterized and coated onto Giemsastained Cowan-I strain of Staphylococcus aureus (S. aureus). The antibody-coated S. aureus were used in a coagglutination test to detect K99+ E. coli isolated from feces of diarrheic calves. The specificity of the test was validated against reference monoclonal antibodies used in co-agglutination tests, as well as in ELISA. Specificity of the monoclonal antibodies was also tested against various Gram negative bacteria. The developed antibodies specifically detected purified K99 antigen in immunoblots, as well as K99+ E. coli in ELISA and co-agglutination tests. The co-agglutination test was specific and convenient for large-scale screening of K99+ E. coli isolates.
Agglutination Tests/methods/*veterinary ; Animals ; *Animals, Newborn ; Antibodies, Monoclonal/*immunology ; Antigens, Surface/immunology/isolation & purification ; Bacterial Toxins/immunology/isolation & purification ; Cattle ; Cattle Diseases/*immunology/*microbiology ; Chromatography, Gel/veterinary ; Chromatography, Ion Exchange/veterinary ; Chromatography, Liquid/veterinary ; Diarrhea/immunology/*veterinary ; Electrophoresis, Polyacrylamide Gel/veterinary ; Enzyme-Linked Immunosorbent Assay/veterinary ; Escherichia coli/*immunology ; Escherichia coli Infections/immunology/*veterinary ; Immunoblotting/veterinary ; Staphylococcus aureus

Helicobacter pylori (H. pylori) infection is acquired mainly in early childhood but the precise transmission routes are unclear. This study examined the maternal H. pylori infection status in order to determine the potential of perinatal transmission. These issues were investigated using an experimental murine model, the Mongolian gerbil, which has been reported to be the most suitable laboratory animal model for studying H. pylori. Pregnant Mongolian gerbils, infected experimentally with H. pylori, were divided into two groups. The stomachs of the mother and litters were isolated and assessed for the transmission of H. pylori at the prenatal period (2 weeks after pregnancy) and at the parturition day. The bacterial culture, polymerase chain reaction (PCR) and rapid urease test were used to examine the presence of the transmitted H. pylori. There was no H. pylori observed in any of the fetuses during pregnancy and in the litters at parturition. This suggests that vertical infection during the prenatal period or delivery procedure is unlikely to be route of mother-tochild transmission of a H. pylori infection.
Animals ; Animals, Newborn ; Disease Models, Animal ; *Disease Transmission, Vertical ; Female ; Gerbillinae ; Helicobacter Infections/microbiology/*transmission ; Helicobacter pylori/*growth&development ; Male ; Polymerase Chain Reaction ; Pregnancy ; Pregnancy Complications, Infectious/*microbiology ; Specific Pathogen-Free Organisms ; Stomach Diseases/*microbiology

OBJECTIVETo investigate the expression of glial fibrillary acidic protein (GFAP), GFAP mRNA and interleukin-1beta mRNA (IL-1beta mRNA), tumor necrosis factor-alpha mRNA (TNF-alpha mRNA) in neonatal rat brain after intrauterine infection.

METHODSEscherichia coli (E. coli) was inoculated into both uterine horns of pregnant rats when gestation was 70% complete (15 days). The control group was treated with normal saline. The pups were killed on the postnatal day 1 (P1), P3 and P7, respectively. The cerebral white matter damage of the neonatal rats was determined by HE staining. Immunohistochemistry was used for evaluation of GFAP expression in neonatal rat brains and RT-PCR to analyze GFAP mRNA, IL-1beta mRNA and TNF-alpha mRNA expression at P1, P3 and P7.

RESULTSThe major histopathological changes in neonatal cerebral white matter at P7 after intrauterine infections were: weak staining of cerebral white matter and focal rarefaction. GFAP-positive cells were observed in both the control and the E. coli-treated groups. The numbers of GFAP-positive cells of the E. coli-treated group pups were markedly increased in periventricular white matter and hippocampus at P7 compared with those of the control group (periventricular white matter: 9.73 +/- 3.55 vs 5.67 +/- 1.90, P < 0.05 and hippocampus: 7.81 +/- 3.61 vs 2.16 +/- 1.11, P < 0.05, respectively). No significantly different levels of GFAP expression in corpus callosum were found between two groups (P > 0.05). The expression of GFAP mRNA in brain of the E. coli-treated neonatal rat was higher than the control at P1, P3 (P1: 0.25 +/- 0.07 vs 0.15 +/- 0.08, P < 0.05 and P3: 0.50 +/- 0.09 vs 0.39 +/- 0.08, P < 0.05, respectively), but the expression of GFAP mRNA in brain of the neonatal rat at P7 had no significant difference between two groups (P > 0.05). The expression of IL-1beta mRNA and TNF-alpha mRNA in brain of the E. coli-treated neonatal rat were higher than of the control at P1 (IL-1beta mRNA: 0.83 +/- 0.19 vs 0.50 +/- 0.30, P < 0.05 and TNF-alpha mRNA: 0.74 +/- 0.30 vs 0.30 +/- 0.20, P < 0.05, respectively), but the expression of IL-1beta mRNA and TNF-alpha mRNA in brain of the neonatal rat at P3 and P7 had no significant difference between two groups (P > 0.05).

CONCLUSIONSThe intrauterine infection could cause neonatal white matter damage and IL-1beta, TNF-alpha may be a mechanism mediating between the two events.

Animals ; Animals, Newborn ; Brain ; metabolism ; pathology ; Disease Models, Animal ; Escherichia coli Infections ; microbiology ; physiopathology ; Female ; Glial Fibrillary Acidic Protein ; analysis ; genetics ; Immunohistochemistry ; Interleukin-1 ; genetics ; Pregnancy ; Pregnancy Complications, Infectious ; microbiology ; physiopathology ; RNA, Messenger ; metabolism ; Rats ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Necrosis Factor-alpha ; genetics ; Uterus ; microbiology