Characteristics of the electrodermal response. A model for analysis of central sympathetic reactivity

In ligated intestinal loops of actively immunized adult mice, growth of V. cholerae 569B was suppressed approximately seven fold when compared to bacterial growth in non-immune animals. Similarly, growth of V. cholerae 569B was reduced in mice immunized with a hybrid vibrio strain, NCV569B-165, which shares only flagella antigens with V. cholerae 569B. Immunofluorescence studies of intestinal loop contents and intestinal sections indicated that, in non-immune mice, vibrios coated the intestinal mucosa. In contrast, the intestinal mucosa of immune animals was almost free of bacteria. The vibrios were found agglutinated in the intestinal lumen contents of immune animals. It was concluded that immunization suppressed the growth of V. cholerae in the intestinal lumen and the possibility that bacterial agglutination mediates this growth suppression is discussed.     

Phenotypic expression of a mannose-sensitive hemagglutinin by a Vibrio cholerae O1 E1Tor strain and evaluation of its role in intestinal adherence and colonization

A Vibrio cholerae O1 strain (1150) of the EIT or biotype and Ogawa serotype with haemagglutination (HA) activity was subjected to TnphoA mutagenesis. Out of several mutants isolated, one HA- and another HA+ mutant were further characterised. The HA- mutant showed about 50% reduction in its intestinal adherence capacity in vitro and about 9-fold decrease of its colonisation ability in vivo, as compared to the wild-type strain. Subsequent studies showed that the HA activity of strain 1150 was mediated by a mannose-sensitive haemagglutinin (MSHA). Thus, the phenotypic expression of MSHA appears to be partly responsible for the intestinal adherence and colonisation properties of strain 1150.     

Heart signal recognition by Hidden Markov Models: the ECG case

From December 1989 to May 1990, 315 faecal samples from children under 5 years old with diarrhoea (215) and without diarrhoea (100) seen at paediatric clinics were investigated for bacterial, viral and parasitic enteropathogens. Standard and recently described methods were used for the investigations, which revealed that 74.9% of children with diarrhoea were infected with enteropathogens compared with 28% of controls. In the diarrhoeal group, 59.1% had a bacterial, 26.5% a viral and 2.3% a parasitic aetiology. Rotavirus was the pathogen most frequently detected, accounting for 22.3% of positive findings in the group with diarrhoea versus 9% in the control group. Other important agents were: enterotoxigenic Escherichia coli (ETEC) (14.4 versus 6%), enteropathogenic E. coli (EPEC) (10.7 versus 5%), enteroadherent E. coli (EAEC) (9.3 versus 4%), enterohaemorrhagic E. coli (EHEC) (5.1 versus 3%) and Salmonella spp. (3.3 versus 1%). The following enteropathogens were detected exclusively in the diarrhoeal stools: Shigella spp. (5.1%), Yersinia enterocolitica (0.9%), Aeromonas hydrophila (1.4%), Entamoeba histolytica (0.5%), Giardia lamblia (0.5%), Trichomonas hominis (0.5) and Trichuris trichiura (0.9%). The detection rates of rotavirus, EPEC and EAEC were much greater in the diarrhoeal than in the control patients. No Vibrio cholerae, enteroinvasive E. coli (EIEC), Plesiomonas spp. or Cryptosporidium spp. were detected in this study. Our data suggest that both the traditional and newly recognised diarrhoeal agents are important causes of diarrhoea in the children under 5 years old in Lagos, Nigeria.     

Mucosal and disseminated candidiasis in gnotobiotic SCID mice

The alimentary tracts of germ-free SCID (severe combined immunodeficient) mice were susceptible to colonization with Candida albicans. Large viable populations (10(6)-10(8) colony forming units g-1) of C. albicans, in pure culture, were present in all sections of the intestinal tract. Candida-colonized SCID mice, sacrificed at various time intervals over a 16 week study, manifested chronic superficial mucosal candidiasis of keratinized epithelial surfaces (tongue and stomach). Despite the continuous presence of large viable populations of C. albicans in their intestinal tract, only superficial mucosal candidiasis and no progressive disseminated candidiasis of endogenous origin was evident in these mice. Treatment with cyclophosphamide (100 mg kg-1, intraperitoneally) enhanced the susceptibility of SCID mice to mucosal (tongue and stomach) candidiasis. Gnotobiotic (C. albicans-colonized) SCID mice were also found to be as resistant as immunocompetent BALB/c mice to acute (intravenous challenge) renal candidiasis. Colonization of the alimentary tract with a bacterial flora appeared to enhance the resistance of SCID mice to disseminated candidiasis. This study demonstrates that innate immune mechanisms (phagocytic and/or NK cells), in the absence of functional T- and B-cells, play an important role in the resistance of SCID mice to mucosal and disseminated candidiasis of endogenous (intestinal tract) or acute (intravenous challenge) origin.     

Role of rpoS in stress survival and virulence of Vibrio cholerae

Vibrio cholerae is known to persist in aquatic environments under nutrient-limiting conditions. To analyze the possible involvement of the alternative sigma factor encoded by rpoS, which is shown to be important for survival during nutrient deprivation in several other bacterial species, a V. cholerae rpoS homolog was cloned by functional complementation of an Escherichia coli mutant by using a wild-type genomic library. Sequence analysis of the complementing clone revealed an 1.008-bp open reading frame which is predicted to encode a 336-amino-acid protein with 71 to 63% overall identity to other reported rpoS gene products. To determine the functional role of rpoS in V. cholerae, we inactivated rpoS by homologous recombination. V. cholerae strains lacking rpoS are impaired in the ability to survive diverse environmental stresses, including exposure to hydrogen peroxide, hyperosmolarity, and carbon starvation. These results suggest that rpoS may be required for the persistence of V. cholerae in aquatic habitats. In addition, the rpoS mutation led to reduced production or secretion of hemagglutinin/protease. However, rpoS is not critical for in vivo survival, as determined by an infant mouse intestinal competition assay.     

Analysis of the roles of antilipopolysaccharide and anti-cholera toxin immunoglobulin A (IgA) antibodies in protection against Vibrio cholerae and cholera toxin by use of monoclonal IgA antibodies in vivo

Secretory immunoglobulin A (IgA) antibodies (sIgA) directed against cholera toxin (CT) and surface components of Vibrio cholerae are associated with protection against cholera, but the relative importance of specific sIgAs in protection is unknown. A monoclonal IgA directed against the V. cholerae lipopolysaccharide (LPS), secreted into the intestines of neonatal mice bearing hybridoma tumors, was previously shown to provide protection against a lethal oral dose of 10(7) V. cholerae cells. We show here that a single oral dose of 5 to 50 micrograms of the monoclonal anti-LPS IgA, given within 2 h before V. cholerae challenge, protected neonatal mice against challenge. In contrast, an oral dose of 80 micrograms of monoclonal IgA directed against CT B subunit (CTB) failed to protect against V. cholerae challenge. A total of 80 micrograms of monoclonal anti-CTB IgA given orally protected neonatal mice from a lethal (5-micrograms) oral dose of CT. Secretion of the same anti-CTB IgA antibodies into the intestines of mice bearing IgA hybridoma backpack tumors, however, failed to protect against lethal oral doses of either CT (5 micrograms) or V. cholerae (10(7) cells). Furthermore, monoclonal anti-CTB IgA, either delivered orally or secreted onto mucosal surfaces in mice bearing hybridoma tumors, did not significantly enhance protection over that provided by oral anti-LPS IgA alone. These results demonstrate that anti-LPS sIgA is much more effective than anti-CT IgA in prevention of V. cholerae-induced diarrheal disease.     

Effect of different combinations of dietary additives on bacterial translocation and survival in gut-derived sepsis

BACKGROUND: Dietary arginine, glutamine, and fish oil each have been shown to improve resistance to infection. The purpose of this study was to assess the potential benefit of different combinations and amounts of these components on bacterial translocation and related mortality during gut-derived sepsis. METHODS: Balb/c mice were fed for 10 days with an AIN-76A diet supplemented with different combinations and percentages of arginine, glutamine, glycine, fish oil, and medium-chain triglycerides. Controls were fed a complete AIN-76A diet or chow. After 10 days of feeding, all animals were transfused. On day 15, the animals were gavaged with 10(10) 111In-radiolabeled or unlabeled Escherichia coli and given a 30% burn injury. Animals gavaged with unlabeled bacteria were observed for survival (n = 317). Groups that showed the best survival as well as control groups were gavaged with labeled bacteria and killed 4 hours postburn (n = 60) for harvest of mesenteric lymph nodes, liver and spleen. RESULTS: Mice fed diets enriched with 5% fish oil + 2% arginine, 2% arginine + 2% glutamine, or 5% fish oil + 2% glutamine had higher survival than control groups. The animals fed fish oil+glutamine had significantly reduced translocation to the liver and spleen. Animals fed arginine+glutamine had an enhanced ability to kill translocated organisms in the liver compared with other groups. Fish oil+arginine improved both barrier function and microbial killing. CONCLUSIONS: Feeding with arginine+glutamine, fish oil+arginine, or fish oil+glutamine supplemented diets positively affects the outcome in a gut-derived sepsis model.     

Validation of a volunteer model of cholera with frozen bacteria as the challenge

To evaluate a standardized inoculum of Vibrio cholerae for volunteer challenge studies, 40 healthy adult volunteers were challenged at three different institutions with a standard inoculum prepared directly from vials of frozen, virulent, El Tor Inaba V. cholerae N16961, with no further incubation. Groups of 5 volunteers, with each group including 2 volunteers with blood group O, were given a dose of 10(5) CFU, and 34 of the 40 volunteers developed diarrhea (mean incubation time, 28 h). Transient fevers occurred in 15 (37.5%) of the volunteers. V. cholerae was excreted by 36 of 40 volunteers. Five additional volunteers received 10(4) CFU, and four developed diarrhea but with a lower average purging rate than required for the model. Of the 40 volunteers, 37 developed rises in their vibriocidal and antitoxin titers similar to those in previous groups challenged with freshly harvested bacteria. We conclude that challenge with frozen bacteria results in a reproducible illness similar to that induced by freshly harvested bacteria. Use of this model should minimize differences in attack rates or severity when groups are challenged at different times and in different institutions.     

Experimental investigation of the distribution of residual strains in the artery wall

Diarrheal diseases often result from ingestion of contaminated water or food. The population of La Paz, Bolivia is directly or indirectly exposed to the sewage-contaminated La Paz River. We conducted a bacteriologic survey of the La Paz River to quantify the level of bacterial contamination, with particular reference to enteropathogens. A total bacterial count exceeding 10(6) colony-forming units (CFU)/ml, including lactose fermenting and nonfermenting, gram-negative bacilli of approximately 10(5) CFU/ml, respectively, were detected in river water samples collected near two densely populated areas. A total bacterial count of 10(5) CFU/ml was also detected at the most downstream area of the river near a sparsely populated area. At four sampling locations, several enteropathogens were detected, including five enterotoxigenic Escherichia coli (ETEC) (serotype O6, O15, and O159), two enteropathogenic E. coli (EPEC) (serotype O44), two enteroinvasive E. coli (EIEC) (serotype O29), and three Salmonella O4 group isolates. The heat-labile enterotoxin gene and the invasive toxin gene were detected in all ETEC and EIEC isolates by polymerase chain reaction analysis. Nine isolates of E. coli were found by the agar dilution method to be susceptible to ampicillin, kanamycin, nalidixic acid, tetracycline, and chloramphenicol, and ampicillin resistance was found in only two isolates of EIEC 7-4 (serotype O29) and EPEC 7-5 (serotype O44). Ampicillin resistance was coded on plasmids and transferred conjugatively to E. coli chi1037 at a frequency of 10(-5) CFU/donor by the broth mating method. Strains of Aeromonas caviae, which can cause diarrheal disease in infants, were detected in vegetables grown in fields irrigated by water from the La Paz River. The survival of nine isolates of E. coli in filtered river water was compared with that of laboratory strains (E. coli chi1037, W3110, and ATCC29577). The survival time of seven isolates, excluding two ampicillin-resistant isolates, was markedly longer than that of the laboratory strains. Our results show a high bacterial contamination of the La Paz river and suggest that such levels may contribute to the high incidence of diarrheal disease in the city of La Paz.     

Characteristics of women choosing birth center care

Certain strains of mice, designated V beta a, have a deletion of the gene segments encoding the beta chain of the T-cell receptor variable region. These mice do not express 40 to 50% of the T-cell receptor V beta chains. In this study, we examined the influence of this deletion on susceptibility to Histoplasma capsulatum. In addition, H. capsulatum-injected V beta a mice were tested for their capacity to generate T-cell dependent responses to H. capsulatum antigens. Susceptibility profiles of V beta a mice, SWR/J (H-2q), SJL/J (H-2s) and C57L-(H-2b), were compared to V beta b strains, C57BL/6 (H-2b) and DBA/l (H-2q), following intravenous (IV) injection of sublethal and lethal inocula of H. capsulatum yeast cells. One week after injection of 6 x 10(5) yeast cells, the spleens of SWR/J, SJL/J and C57L mice contained 5- to 7-fold fewer colony forming units (CFU) than spleens of C57BL/6 mice. Approximately 50% fewer CFU of H. capsulatum were recovered from the spleens of DBA/l mice compared to those from C57BL/6 animals. Subsequently, groups of mice were challenged IV with either 1.5 x 10(7) or 7.5 x 10(6) yeast cells and observed for 30 days. Survival of SWR/J,SJL/J, C57L and DBA/l mice was significantly prolonged compared to C57BL/6 mice. V beta a and DBA/l mice injected with viable H. capsulatum yeast cells mounted a delayed-type hypersensitivity response to an extract from the cell wall and cell membrane of yeast cells and to HIS-62, a purified antigen derived therefrom.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunogenicity and protective role of three formulations of oral cholera vaccine

Three formulations of oral cholera vaccine were compared with respect to their immunogenicity and protective ability in a rat ileal loop model. Eight-week-old Wistar rats were divided into five groups. The first group received orally vaccine A consisting of liposome-associated V. cholera lipopolysaccharide, fimbriae and procholeragenoid, whereas the rats of groups 2 and 3 received orally vaccines B and C consisting of heatkilled fimbriated and non-fimbriated whole cell V. cholerae, respectively. Rats of groups 4 and 5 were controls that received orally liposomes alone and normal saline solution, respectively. It was found that vaccine A elicited stronger immune responses to all three V. cholerae antigens. The antibody responses were detected in both serum and intestinal lavage samples. Vaccine B elicited only modest serum and intestinal responses to V. cholerae fimbriae (anti-F). No detectable immune response was found in rats of group 3 immunized with vaccine C. Rats immunized with vaccines A and B had a similar order of magnitude of numbers of vibrios adhered to their intestinal mucosa. These numbers were less than those associated with the intestinal tissues of control rats of groups 4 and 5 by about two orders of magnitude. Although without any detectable immune response, rats of group 3 that were immunized with vaccine C showed some reduction in numbers of vibrios associated with their intestinal mucosa. The numbers of vibrios recovered from the intestinal segments of rats of all treatment groups were in the order group 1 = 2 < 4 = 5. Electron micrography also revealed patches of vibrio colonization on the mucosa of rats of groups 3, 4 and 5. These features were not found in the groups vaccinated with vaccines A and B. The inhibition of vibrio colonization afforded by the vaccines was biotype- and serotype-non-specific. The results suggest that the heat-killed whole cell fimbriated V. cholerae may be an alternative vaccine preparation to the liposome-associated refined antigen vaccine at a lower cost.     

Estimation of the viability of Vibrio cholerae 0139 by assessing cell membrane integrity

Changes in the viability of Vibrio cholerae 0139 Bengal, estimated by cellular membrane integrity, in batch culture over 35 days, were investigated. Data indicated an initial period of rapid growth with up to 30% of bacterial mortality, followed by a period of slower growth, lower culturability but higher viability, from day 7 onwards. The size of viable bacteria significantly decreased during the incubation time, whilst the size of dead bacteria showed a less pronounced decrease. V. cholerae 0139 changed from a straight or curved rod shape to a spherical shape. This study shows that BacLight dyes are a fast and useful tool to examine health risk-associated bacteria, providing useful information about their viability and concentration.     

Oligomerization of Vibrio cholerae cytolysin yields a pentameric pore and has a dual specificity for cholesterol and sphingolipids in the target membrane

Vibrio cholerae cytolysin permeabilizes animal cell membranes. Upon binding to the target lipid bilayer, the protein assembles into homo-oligomeric pores of an as yet unknown stoichiometry. Pore formation has been observed with model liposomes consisting of phosphatidylcholine and cholesterol, but the latter were much less susceptible to the cytolysin than were erythrocytes or intestinal epithelial cells. We here show that liposome permeabilization is strongly promoted if cholesterol is combined with sphingolipids, whereby the most pronounced effects are observed with monohexosylceramides and free ceramide. These two lipid species are prevalent in mammalian intestinal brush border membranes. We therefore propose that, on its natural target membranes, the cytolysin has a dual specificity for both cholesterol and ceramides. To assess the stoichiometry of the pore, we generated hybrid oligomers of two naturally occurring variants of the toxin that differ in molecular weight. On SDS-polyacrylamide gel electrophoresis, the mixed oligomers formed a pattern of six distinct bands. Ordered by decreasing electrophoretic mobility, the six oligomer species must comprise 0 to 5 subunits of the larger form; the pore thus is a pentamer. Due to both lipid specificity and pore stoichiometry, V. cholerae cytolysin represents a novel prototype in the class of bacterial pore-forming toxins.     

Diagnosis of Lyme borreliosis with western blotting]

The endemic and seasonal nature of cholera depends upon the survival of Vibrio cholerae 01 in a viable but not necessarily culturable state in ecologic niches in aquatic environments during interepidemic periods. To understand the ecology of V. cholerae it is necessary to know which aquatic ecosystems can harbor it and thus contribute to the endemic presence of cholera in Latin America. This article presents a summary of the ecology of V. cholerae 01, organized according to the abiotic and biotic factors that are relevant to the microbe's survival in aquatic environments. This pathogen finds favorable conditions in waters characterized by moderate salinity, high nutrient content, warm temperature, neutral or slightly alkaline pH, and the presence of aquatic macrophages, phytoplankton, zooplankton, fish, mollusks, and crustaceans. These ecologic conditions are typical of estuaries and coastal swamps, and toxigenic V. cholerae 01 is now considered an autochthonous member of the microbial flora of these environments. The microorganism has also shown the ability to colonize freshwater ecosystems in its viable but not necessarily culturable form, if organic or inorganic substrates that favor its survival are available.     

Bombesin protects against bacterial translocation induced by three commercially available liquid enteral diets: a prospective, randomized, multigroup trial

OBJECTIVE: To test the hypothesis that certain commercially available liquid diets would cause bacterial translocation and that this diet-induced translocation could be reduced with bombesin (an intestinal hormone stimulant). DESIGN: Prospective, multigroup trial in which animals fed each test diet were randomized to receive either bombesin or saline for 7 days. On day 7, the mice were killed and their organs were cultured for translocating bacteria, their cecal bacterial population concentrations were measured, and ileal and jejunal mucosal protein content was determined. SETTING: Small animal laboratory. SUBJECTS: Outbred ICR mice weighing 25 to 35 g. INTERVENTIONS: Mice received bombesin (10 micrograms/kg) or saline subcutaneously three times daily for 7 days before sacrifice. MEASUREMENTS AND MAIN RESULTS: The incidence of bacterial translocation to the mesenteric lymph node was significantly increased (p < .05) in mice fed Vivonex (53%), Criticare (67%), or Ensure (60%) compared with chow-fed controls (0%). All three liquid diets were associated with the development of cecal bacterial overgrowth and loss of jejunal and ileal mucosal protein content. Bombesin reduced the incidence of bacterial translocation and loss of mucosal protein content in all three liquid diet groups (p < .05), but did not prevent diet-induced cecal bacterial overgrowth. CONCLUSIONS: Three different liquid diets induced bacterial translocation to the mesenteric lymph node. Since bombesin was effective in reducing bacterial translocation, it appears that bacterial translocation induced by these liquid diets can be modulated hormonally.     

Post modern medicine

BACKGROUND: Nucleoside-nucleotide mixture has been shown to improve gut morphology and reduce the incidence of bacterial translocation in protein deficient mice. AIMS: To compare the reparative effect of nucleoside-nucleotide mixture and their individual components on maintenance of gut integrity and bacterial translocation based on their differential metabolism and utilisation. METHODS: ICR (CD-1) mice were randomised into eight groups of 10 animals each and fed 20% casein diet (control), protein free diet, or protein free diet supplemented with 3 M cytidine, uridine, thymidine, inosine, guanosine monophosphate, or nucleoside-nucleotide mixture for four weeks. On the fourth week, each mouse was injected lipopolysaccharide intraperitoneally (50 micrograms/500 microliters) and the incidence of bacterial translocation, caecal bacterial populations, and the ileal histology, noted 48 hours later. RESULTS: The death rate in the control group was 40% compared with 10% in the nucleoside-nucleotide mixture and 20% each in the individual components groups, respectively. Bacterial translocation to the mesenteric lymph node did occur in 100% of the surviving mice fed the control diet in comparison with 44% (nucleoside-nucleotide), 50% (cytidine), 75% (thymidine), 75% (uridine), 63% (inosine), and 63% (guanosine monophosphate). Histologically, the damage to the gut was more distinct in the protein free diet group. Villous height, crypt depth, and wall thickness in the nucleoside-nucleotide mixture group mean (SEM) (5.01 (0.34); 0.87 (0.14); 0.33 (0.10)), were respectively, higher compared with the protein free diet (3.34 (0.34); 0.61 (0.03); 0.18 (0.04)) group. In the cytidine group, crypt depth (0.86) (0.08)), and wall thickness (0.30 (0.002)) were higher. The same measurements in the components groups tended to be higher than the protein free diet group. Caecal bacterial populations were, however, similar in all groups. CONCLUSIONS: These results suggest that dietary nucleosides and nucleotides are essential nutrients for intestinal repair; nucleotides or cytidine provide a better response.     

Induction of the lysogenic phage encoding cholera toxin in naturally occurring strains of toxigenic Vibrio cholerae O1 and O139

In toxigenic Vibrio cholerae, the CTX genetic element which carries the genes for cholera toxin (CT) is the genome of a lysogenic bacteriophage (CTXPhi). Clinical and environmental strains of V. cholerae O1 or O139 and stools that were culture positive for cholera were analyzed to study the induction and transmission of CTXPhi. To our knowledge, this is the first report of the examination of CTXPhi in clinical materials and in naturally occurring strains. DNA probe analysis revealed that 4.25% (6 of 141) of the isolated V. cholerae strains spontaneously produced a detectable level of extracellular CTXPhi particles in the culture supernatants whereas another 34.04% (48 of 141) produced CTXPhi particles when induced with mitomycin C. CTXPhi isolated from 10 clinical or environmental strains infected a CT-negative recipient strain, CVD103, both inside the intestines of infant mice and under laboratory conditions. All culture-positive stools analyzed were negative for the presence of CTXPhi both in the DNA probe assay and by in vivo assay for the infection of the recipient strain in infant mice. These results suggested that naturally occurring strains of toxigenic V. cholerae are inducible lysogens of CTXPhi but that cholera pathogenesis in humans is not associated with the excretion of CTXPhi particles in stools, indicating that induction of the phage may not occur efficiently inside the human intestine. However, in view of the efficient transmission of the phage under conditions conducive to the expression of toxin-coregulated pili, it appears that propagation of CTXPhi in the natural habitat may involve both environmental and host factors.     

Expression of mucin-type glycoprotein K88 receptors strongly correlates with piglet susceptibility to K88(+) enterotoxigenic Escherichia coli, but adhesion of this bacterium to brush borders does not

Three antigenic variants of the K88 fimbrial adhesin exist in nature, K88ab, K88ac, and K88ad. Enterotoxigenic Escherichia coli (ETEC) strains that produce these fimbriae cause life-threatening diarrhea in some but not all young pigs. The susceptibility of pigs to these organisms has been correlated with the adherence of bacteria to isolated enterocyte brush borders. Whether that correlation holds for multiple K88 variants and over a broad genetic base of pigs is unknown and was the impetus for this study. We also desired to examine the correlation of the expression of a porcine intestinal brush border mucin-type glycoprotein (IMTGP) which binds K88ab and K88ac with the susceptibility of piglets to K88(+) ETEC. Of 31 neonatal gnotobiotic pigs inoculated with K88ab+ or K88ac+ ETEC, 13 developed severe diarrhea, became dehydrated, and died or became moribund. Another pig became severely lethargic but not dehydrated. In vitro brush border adherence analysis was not possible for 10 of the severely ill pigs due to colonization by challenge strains. However, of the 17 pigs that did not become severely ill, 8 (47%) had brush borders that supported the adherence of K88ab+ and K88ac+ bacteria in vitro, suggesting a poor correlation between in vitro brush border adherence and piglet susceptibility to K88(+) ETEC. By contrast, the expression of IMTGP was highly correlated with susceptibility to K88(+) ETEC. Of the 12 pigs that produced IMTGP, 11 developed severe diarrhea. The other pig that produced IMTGP became lethargic but not severely diarrheic. Only 2 of 18 pigs that did not produce IMTGP became severely diarrheic. Colonizing bacteria were observed in histologic sections of intestines from all pigs that expressed IMTGP except for the one that did not develop severe diarrhea. However, colonizing bacteria were observed in histologic sections from only one pig that did not produce IMTGP. The bacterial concentration in the jejuna and ilea of pigs expressing IMTGP was significantly greater (P < 0.005) than that in pigs not expressing IMTGP. These observations suggest the IMTGP is a biologically relevant receptor for K88ab+ and K88ac+ E. coli or a correlate for expression for such a receptor.     

Rapid detection of Vibrio cholerae O139 Bengal from stool specimens by PCR

In a previous study using pure bacterial cultures in a PCR assay, a primer pair corresponding to a unique chromosomal region of Vibrio cholerae O139 Bengal generated an amplicon from only V. cholerae O139 Bengal. PCR with the same primer pair was used to screen 180 diarrheal stool specimens. All the 67 V. cholerae O139 culture-positive stool specimens were positive by PCR, and the remaining specimens, which contained either other recognized enteric pathogens or no pathogens, were all negative by PCR.     

Arginine-supplemented diets inhibit endotoxin-induced bacterial translocation in mice

We studied the effects of supplemental dietary arginine (ARG) on endotoxin-induced bacterial translocation. Mice were fed a 20%-casein diet (control) or a 20%-casein diet supplemented with 2% or 4% ARG and then injected with lipopolysaccharide (1 mg/500 microliters). The incidence of bacterial translocation was noted by the recovery of viable organisms from the mesenteric lymph node (MLN) and spleen. The mortality rates of the mice were 40%, 10%, and 20% in the control group and 2%- and 4%-ARG groups, respectively. Of the surviving mice, bacterial translocation occurred in 100% of the control group, in 56% (MLN) and 56% (spleen) in the 2%-ARG group, and in 36% (MLN) and 25% (spleen) in the 4%-ARG group. Quantitative colony counts and median numbers of viable bacteria were lower (p < 0.05) in the 2%-ARG group and slightly lower in the 4%-ARG group compared with the control group. MLN and spleen weights expressed as a percentage of body weight were heavier (p < 0.05) only in the 2%-ARG group. These results support the concept that bacteria may translocate from the gut to other organs and be a potential source of lethal infection after injury, and that supplementation with 2% or 4% ARG could improve outcome.