Intracellular Campylobacter-like organism from ferrets and hamsters with proliferative bowel disease is a Desulfovibrio sp

Antibiotic-Resistant Desulfovibrio Produces H2S from Supplements for Animal Farming

Sulphate-reducing bacteria, primarily Desulfovibrio, are responsible for the active generation of H2S in swine production waste. The model species for sulphate reduction studies, Desulfovibrio vulgaris strain L2, was previously isolated from swine manure characterized by high rates of dissimilatory sulphate reduction. The source of electron acceptors in low-sulphate swine waste for the high rate of H2S formation remains uncertain. Here, we demonstrate the ability of the L2 strain to use common animal farming supplements including L-lysine-sulphate, gypsum and gypsum plasterboards as electron acceptors for H2S production. Genome sequencing of strain L2 revealed the presence of two megaplasmids and predicted resistance to various antimicrobials and mercury, which was confirmed in physiological experiments. Most of antibiotic resistance genes (ARG) are carried by two class 1 integrons located on the chromosome and on the plasmid pDsulf-L2-2. These ARGs, predicted to confer resistance to beta-lactams, aminoglycosides, lincosamides, sulphonamides, chloramphenicol and tetracycline, were probably laterally acquired from various Gammaproteobacteria and Firmicutes. Resistance to mercury is likely enabled by two mer operons also located on the chromosome and on pDsulf-L2-2 and acquired via horizontal gene transfer. The second megaplasmid, pDsulf-L2-1, encoded nitrogenase, catalase and type III secretion system suggesting close contact of the strain with intestinal cells in the swine gut. The location of ARGs on mobile elements allows us to consider D. vulgaris strain L2 as a possible vector transferring antimicrobials resistance determinants between the gut microbiote and microbial communities in environmental biotopes.

Gut microbiota modulates bleomycin-induced acute lung injury response in mice

BACKGROUND

Airway instillation of bleomycin (BLM) in mice is a widely used, yet challenging, model for acute lung injury (ALI) with high variability in treatment scheme and animal outcomes among investigators. Whether the gut microbiota plays any role in the outcome of BLM-induced lung injury is currently unknown.

METHODS

Intratracheal instillation of BLM into C57BL/6 mice was performed. Fecal microbiomes were analyzed by 16s rRNA amplicon and metagenomic sequencing. Germ-free mice conventionalization and fecal microbiota transfer between SPF mice were performed to determine dominant commensal species that are associated with more severe BLM response. Further, lungs and gut draining lymph nodes of the mice were analyzed by flow cytometry to define immunophenotypes associated with the BLM-sensitive microbiome.

RESULTS

Mice from two SPF barrier facilities at the University of Chicago exhibited significantly different mortality and weight loss during BLM-induced lung injury. Conventionalizing germ-free mice with SPF microbiota from two different housing facilities recapitulated the respective donors' response to BLM. Fecal microbiota transfer from the facility where the mice had worse mortality into the mice in the facility with more survival rendered recipient mice more susceptible to BLM-induced weight loss in a dominant negative manner. BLM-sensitive phenotype was associated with the presence of Helicobacter and Desulfovibrio in the gut, decreased Th17-neutrophil axis during steady state, and augmented lung neutrophil accumulation during the acute phase of the injury response.

CONCLUSION

The composition of gut microbiota has significant impact on BLM-induced wasting and death suggesting a role of the lung-gut axis in lung injury.

Evaluation of host and bacterial gene modulation during Lawsonia intracellularis infection in immunocompetent C57BL/6 mouse model

BACKGROUND

Proliferative enteritis caused by Lawsonia intracellularis undermines the economic stability of the swine industry worldwide. The development of cost-effective animal models to study the pathophysiology of the disease will help develop strategies to counter this bacterium.

OBJECTIVES

This study focused on establishing a model of gastrointestinal (GI) infection of L. intracellularis in C57BL/6 mice to evaluate the disease progression and lesions of proliferative enteropathy (PE) in murine GI tissue.

METHODS

We assessed the murine mucosal and cell-mediated immune responses generated in response to inoculation with L. intracellularis.

RESULTS

The mice developed characteristic lesions of the disease and shed L. intracellularis in the feces following oral inoculation with 5 × l07 bacteria. An increase in L. intracellularis 16s rRNA and groEL copies in the intestine of infected mice indicated intestinal dissemination of the bacteria. The C57BL/6 mice appeared capable of modulating humoral and cell-mediated immune responses to L. intracellularis infection. Notably, the expression of genes for the vitamin B12 receptor and for secreted and membrane-bound mucins were downregulated in L. intracellularis -infected mice. Furthermore, L. intracellularis colonization of the mouse intestine was confirmed by the immunohistochemistry and western blot analyses.

CONCLUSIONS

This is the first study demonstrating the contributions of bacterial chaperonin and host nutrient genes to PE using an immunocompetent mouse model. This mouse infection model may serve as a platform from which to study L. intracellularis infection and develop potential vaccination and therapeutic strategies to treat PE.

Dynamic Alterations of the Gut Microbial Pyrimidine and Purine Metabolism in the Development of Liver Cirrhosis

Background: Liver cirrhosis is the common end-stage of liver disease which lacks effective treatment, thus studies to determine prevention targets are an urgent need. The intestinal microbiota (IM) play important roles in modulating liver diseases which are mediated by microbial metabolites. Despite decades of growing microbial studies, whether IM contribute to the development of cirrhosis and the intimate metabolic link remain obscure. Here, we aimed to reveal the dynamic alterations of microbial composition and metabolic signatures in carbon tetrachloride (CCl₄)-induced liver cirrhosis mice.

Methods: CCl₄-treated mice or normal control (NC) were sacrificed (n = 10 per group) after 5 and 15 weeks of intervention. The disease severity was confirmed by Masson’s trichrome or Sirius red staining. Metagenomics sequencing and fecal untargeted metabolomics were performed to evaluate the composition and metabolic function of IM in parallel with the development of cirrhosis.

Results: The CCl₄-treated mice presented liver fibrosis at 5 weeks and liver cirrhosis at 15 weeks indicated by collagen deposition and pseudo-lobule formation, respectively. Mice with liver cirrhosis showed distinct microbial composition from NC, even in the earlier fibrosis stage. Importantly, both of the liver fibrosis and cirrhosis mice were characterized with the depletion of Deltaproteobacteria (p < 0.05) and enrichment of Akkermansia (p < 0.05). Furthermore, fecal metabolomics revealed distinguished metabolomics profiles of mice with liver fibrosis and cirrhosis from the NC. Notably, pathway enrichment analysis pointed to remarkable disturbance of purine (p < 0.001 at 5 weeks, p = 0.034 at 15 weeks) and pyrimidine metabolic pathways (p = 0.005 at 5 weeks, p = 0.006 at 15 weeks) during the development of liver cirrhosis. Interestingly, the disorders of pyrimidine and purine metabolites like the known microbial metabolites thymidine and 2′-deoxyuridine had already occurred in liver fibrosis and continued in cirrhosis.

Conclusion: These novel findings indicated the crucial role of IM-modulated pyrimidine and purine metabolites in the development of liver cirrhosis, which provides microbial targets for disease prevention.

Fecal microbiota changes in NZB/W F1 mice after induction of lupus disease

The association between the gut microbiota and the development of lupus is unclear. We investigated alterations in the gut microbiota after induction of lupus in a murine model using viral peptide of human cytomegalovirus (HCMV). Three treatment arms for the animals were prepared: intraperitoneal injection of HCMVpp65 peptide, adjuvant alone, and PBS injection. Feces were collected before and after lupus induction biweekly for 16S rRNA sequencing. HCMVpp65 peptide immunization induced lupus-like effects, with higher levels of anti-dsDNA antibodies, creatinine, proteinuria, and glomerular damage, compared with mice treated with nothing or adjuvant only. The Simpson diversity value was higher in mice injected with HCMVpp65 peptide, but there was no difference in ACE or Chao1 among the three groups. Statistical analysis of metagenomic profiles showed a higher abundance of various families (Saccharimonadaceae, Marinifiaceae, and Desulfovibrionaceae) and genera (Candidatus Saccharimonas, Roseburia, Odoribacter, and Desulfovibrio) in HCMVpp65 peptide-treated mice. Significant correlations between increased abundances of related genera (Candidatus Saccharimonas, Roseburia, Odoribacter, and Desulfovibrio) and HCMVpp65 peptide immunization-induced lupus-like effects were observed. This study provides insight into the changes in the gut microbiota after lupus onset in a murine model.

Environmental Impact of Sulfate-Reducing Bacteria, Their Role in Intestinal Bowel Diseases, and Possible Control by Bacteriophages

Sulfate-reducing bacteria (SRB) represent a group of prokaryotic microorganisms that are widely spread in the anoxic environment (seabed, riverbed and lakebed sediments, mud, intestinal tract of humans and animals, metal surfaces). SRB species also have an impact on processes occurring in the intestinal tract of humans and animals, including the connections between their presence and inflammatory bowel disease (IBD). Since these SRB can develop antimicrobial resistance toward the drugs, including antibiotics and antimicrobial agents, bacteriophages could represent an additional potential effective treatment. The main objectives of the review were as follows: (a) to review SRB (both from intestinal and environmental sources) regarding their role in intestinal diseases as well as their influence in environmental processes; and (b) to review, according to literature data, the influence of bacteriophages on SRB and their possible applications. Since SRB can have a significant adverse influence on industry as well as on humans and animals health, phage treatment of SRB can be seen as a possible effective method of SRB inhibition. However, there are relatively few studies concerning the influence of phages on SRB strains. Siphoviridae and Myoviridae families represent the main sulfide-producing bacteria phages. The most recent studies induced, by UV light, bacteriophages from Desulfovibrio vulgaris NCIMB 8303 and Desulfovibrio desulfuricans ATCC 13541. Notwithstanding costly and medically significant negative impacts of phages on SRB, they have been the subject of relatively few studies. The current search for alternatives to chemical biocides and antibiotics has led to the renewed interest in phages as antibacterial biocontrol and therapeutic agents, including their use against SRB. Hence, phages might represent a promising treatment against SRB in the future.

Etiopathogenesis of sacroiliitis: implications for assessment and management

The sacroiliac joints connect the base of the sacrum to the ilium. When inflamed, they are suspected to cause low back pain. Inflammation of the sacroiliac joints is called sacroiliitis. The severity of the pain varies and depends on the degree of inflammation. Sacroiliitis is a hallmark of seronegative spondyloarthropathies. The presence or absence of chronic sacroiliitis is an important clue in the diagnosis of low back pain. This article aims to provide a concise overview of the anatomy, physiology, and molecular biology of sacroiliitis to aid clinicians in the assessment and management of sacroiliitis. For this narrative review, we evaluated articles in English published before August 2019 in PubMed. Then, we selected articles related to the painful manifestations of the sacroiliac joint. From the retrieved articles, we found that chronic sacroiliitis may be caused by various forms of spondyloarthritis, such as ankylosing spondyloarthritis. Sacroiliitis can also be associated with inflammatory bowel disease, Crohn’s disease, gout, tuberculosis, brucellosis, and osteoarthritis, indicating common underlying etiological factors. The pathophysiology of sacroiliitis is complex and may involve internal, environmental, immunological, and genetic factors. Finally, genetic factors may also play a central role in progression of the disease. Knowing the genetic pre-disposition for sacroiliitis can be useful for diagnosis and for formulating treatment regimens, and may lead to a substantial reduction in disease severity and duration and to improved patient performance.

Gastrointestinal Diseases of Rabbits

Gastrointestinal stasis syndrome is a very common presentation of an ill rabbit to the veterinarian. The causes involved in this syndrome are often multifactorial, and an inappropriate diet puts the rabbit at a greater risk of developing this syndrome. Complications of this disorder can lead to gastrointestinal obstruction, a life-threatening condition that necessitates aggressive medical and in some case surgical therapy. Rabbits may also be presented with signs of diarrhea. However, abnormal cecotrophs must be differentiated from true intestinal diarrhea. The common causes, diagnosis and management of diarrhea including dysbiosis and enteritis are discussed. Other important causes of gastrointestinal disease are infectious disease and liver lobe torsion. Rabbit hemorrhagic disease virus has a new variant that has been identified in mainland Europe, the United Kingdom, and Australia. Subclinical infection of intestinal coccidiosis is a common cause of weight loss in adult rabbits. Liver lobe torsion is a challenging condition to diagnose in rabbits; this chapter discusses the presenting signs, diagnostic techniques, and therapeutic options.

Do different livestock dwellings on single grassland share similar faecal microbial communities?

Huge numbers of microorganisms reside in livestock faeces and constitute one of the most complex microbial ecosystems. Here, faecal microbial communities of three typical livestock in Xilingol steppe grassland, i.e. sheep, cattle, and horse, were investigated by Illumina MiSeq sequencing and quantitative real-time polymerase chain reaction (qPCR). Firmicutes and Bacteroidetes comprised the majority of bacterial communities in three livestock faeces. Sordariomycetes, Leotiomycetes, and Dothideomycetes were dominant in fungal communities, as well as Methanobacteria and Methanomicrobia were dominant in archaeal communities in three livestock faeces. Similar fungal community dominated in these samples, with 95.51% of the sequences falling into the overlap of three livestock faeces. In contrast, bacterial communities were quite variable among three different livestock faeces, but a similar community was observed in sheep and cattle faeces. Nearly all the archaea were identified as methanogens, whilst the most diverse and abundant methanogens were detected in cattle faeces. Potential pathogens including Bacteroides spp., Desulfovibrio spp., and Fusarium spp. were also detected in livestock faeces. Overall, this study provides the first detailed microbial comparison of typical livestock faeces dwelling on single grassland, and may be help guide management strategies for livestock grazing and grassland restoration.

Isolation and identification of Treponema pedis and Treponema phagedenis-like organisms from bovine digital dermatitis lesions found in dairy cattle in Turkey

The isolation and identification of microorganisms associated with digital dermatitis (DD) in Turkish dairy cattle was investigated using punch skin biopsy samples from typical clinical lesions; they were collected from dairy farms and abattoirs in 5 different geographical locations in Turkey. Morphological characteristics and flagellation types were examined using a transmission electron microscope, and their enzyme profiles by enzyme activation kits; their catalase reaction characteristics were evaluated by the addition of 3% H₂O₂. Their phylogenies were identified using 16S rRNA and the results compared with known gene bank data. Bacterial cells were 5.0 to 18.2 µm long, 0.2 to 0.5 µm wide, and their minimum number of periplasmic flagellum was 4 (4:8:4) with a maximum of 8 (8:16:8). All isolates were catalase negative. Of the spirochetes isolated and identified, group I organisms showed close similarity with Treponema pedis (99% genetic homology), whereas those in group II were similar to Treponema phagedenis (98% homology). This is the first report of specific sub-groups of Treponema spp., isolated from Turkish dairy cattle presenting with DD lesions, being associated with this disease; these morphotypes were similar to those found globally in housed dairy cattle units and are probably significant microorganisms associated with the aetiopathogensis of this infectious disease causing acute bovine lameness. These results suggest that the distribution of DD-associated treponemes is not specific to particular geographic regions of Turkey.

Conservation Implications of Shifting Gut Microbiomes in Captive-Reared Endangered Voles Intended for Reintroduction into the Wild

The Amargosa vole is a highly endangered rodent endemic to a small stretch of the Amargosa River basin in Inyo County, California. It specializes on a single, nutritionally marginal food source in nature. As part of a conservation effort to preserve the species, a captive breeding population was established to serve as an insurance colony and a source of individuals to release into the wild as restored habitat becomes available. The colony has successfully been maintained on commercial diets for multiple generations, but there are concerns that colony animals could lose gut microbes necessary to digest a wild diet. We analyzed feces from colony-reared and recently captured wild-born voles on various diets, and foregut contents from colony and wild voles. Unexpectedly, fecal microbial composition did not greatly differ despite drastically different diets and differences observed were mostly in low-abundance microbes. In contrast, colony vole foregut microbiomes were dominated by Allobaculum sp. while wild foreguts were dominated by Lactobacillus sp. If these bacterial community differences result in beneficial functional differences in digestion, then captive-reared Amargosa voles should be prepared prior to release into the wild to minimize or eliminate those differences to maximize their chance of success.

Sulphate-reducing bacteria from ulcerative colitis patients induce apoptosis of gastrointestinal epithelial cells

The human microbiome consists of a multitude of bacterial genera and species which continuously interact with one another and their host establishing a metabolic equilibrium. The dysbiosis can lead to the development of pathology, such as inflammatory bowel diseases. Sulfide-producing prokaryotes, including sulphate-reducing bacteria (SRB) constituting different genera, including the Desulfovibrio, are commonly detected within the human microbiome recovered from fecal material or colonic biopsy samples. It has been proposed that SRB likely contribute to colonic pathology, for example ulcerative colitis (UC). The interaction of SRB with the human colon and intestinal epithelial cell lines has been investigated using Desulfovibrio indonesiensis as a model mono-culture and in a co-culture with E. coli isolate, and with SRB consortia from human biopsy samples. We find that D. indonesiensis, whether as a mono- or co-culture, was internalized and induced apoptosis in colon epithelial cells. This effect was enhanced in the presence of E. coli. The SRB combination obtained through enrichment of biopsies from UC patients induced apoptosis of a human intestinal epithelial cell line. This response was not observed in SRB enrichments from healthy (non-UC) controls. Importantly, apoptosis was detected in epithelial cells from UC patients and was not seen in epithelial cells of healthy donors. Furthermore, the antibody raised against exopolysaccharides (EPS) of D. indonesiensis cross reacted with the SRB population from UC patients but not with the SRB combination from non-UC controls. This study reinforces a correlation between the presence of sulphate-reducing bacteria and an inflammatory response in UC sufferers.

PREVALENCE OF ANTIBODY TO AND DNA OF LAWSONIA INTRACELLULARIS IN SAMPLES FROM WILD ANIMALS IN KOREA

We evaluated the prevalence of Lawsonia intracellularis infection in three wild animal species in Korea; the Korean water deer ( Hydropotes inermis ), Siberian roe deer ( Capreolus pygargus ), and raccoon dogs ( Nyctereutes procyonoides ). We collected 136 sera and 109 fecal samples from individuals in 10 Wildlife Rescue and Conservation Centers. Serum samples were tested for anti- L. intracellularis antibodies using a blocking enzyme-linked immunosorbent assay (bELISA), and fecal samples were subjected to a real-time PCR assay for L. intracellularis . Thirty-five (25.7%) sera and 36 (33.0%) fecal samples were positive. We found a higher proportion of positive sera (64.7%, χ²=15.439, P<0.01) and feces (58.8%, χ²=6.126, P<0.05) in raccoon dogs (χ²=11.855, P<0.01) than in the other species (20% positive sera and 29% positive feces in Korean water deer; 20% positive sera and 25% positive feces in Siberian roe deer). Our data indicate infection by L. intracellularis in Korean water deer, Siberian roe deer, and raccoon dogs throughout the country. It is imperative to know whether these infected animal species are natural hosts for L. intracellularis in addition to domestic pigs ( Sus scrofa domesticus).

Alcohol Consumption and Periodontitis: Quantification of Periodontal Pathogens and Cytokines

BACKGROUND

There are few studies on periodontal status related to microbiologic and immunologic profiles among individuals not or occasionally using alcohol and those with alcohol dependence. The aim of this study is to determine the effect of alcohol consumption on the levels of subgingival periodontal pathogens and proinflammatory cytokines (interleukin [IL]-1β and tumor necrosis factor [TNF]-α) in the gingival fluid among individuals with and without periodontitis.

METHODS

This observational analytic study includes 88 volunteers allocated in four groups (n = 22): individuals with alcohol dependence and periodontitis (ADP), individuals with alcohol dependence and without periodontitis (ADNP), individuals not or occasionally using alcohol with periodontitis (NAP), and individuals not or occasionally using alcohol without periodontitis (NANP). Levels of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Eikenella corrodens, and Fusobacterium nucleatum were determined by real-time polymerase chain reaction on the basis of the subgingival biofilm, and IL-1β and TNF-α were quantified by enzyme-linked immunosorbent assay in gingival fluid samples.

RESULTS

Individuals with alcohol dependence showed worse periodontal status and higher levels of P. intermedia, E. corrodens, F. nucleatum, and IL-1β than non-users. No significant correlations between TNF-α and bacterial levels were observed. However, in the ADP group, higher levels of E. corrodens were correlated with higher levels of IL-1β.

CONCLUSION

A negative influence of alcohol consumption was observed on clinical and microbiologic periodontal parameters, as well as a slight influence on immunologic parameters, signaling the need for additional studies.

Biology and Diseases of Rabbits

Beginning in 1931, an inbred rabbit colony was developed at the Phipps Institute for the Study, Treatment and Prevention of Tuberculosis at the University of Pennsylvania. This colony was used to study natural resistance to infection with tuberculosis (Robertson et al., 1966). Other inbred colonies or well-defined breeding colonies were also developed at the University of Illinois College of Medicine Center for Genetics, the Laboratories of the International Health Division of The Rockefeller Foundation, the University of Utrecht in the Netherlands, and Jackson Laboratories. These colonies were moved or closed in the years to follow. Since 1973, the U.S. Department of Agriculture has reported the total number of certain species of animals used by registered research facilities (1997). In 1973, 447,570 rabbits were used in research. There has been an overall decrease in numbers of rabbits used. This decreasing trend started in the mid-1990s. In 2010, 210,172 rabbits were used in research. Despite the overall drop in the number used in research, the rabbit is still a valuable model and tool for many disciplines.

Biology and Diseases of Hamsters

The hamster species used as research models include the Syrian (golden), Mesocricetus auratus; the Chinese (striped-back), Cricetulus griseus; the Armenian (gray), C. migratorius; the European, Cricetus cricetus; and the Djungarian, Phodopus campbelli (Russian dwarf) and P. sungorus (Siberian dwarf). Hamsters are classified as members of the order Rodentia, suborder Myomorpha, superfamily Muroidea and in family Cricetidae. Animals in this family are characterized by large cheek pouches, thick bodies, short tails, and an excess of loose skin. They have incisors that erupt continuously and cuspidate molars that do not continue to grow ((I 1/1, C 0/0, PM 0/0, M 3/3) × 2 = 16). In 2010, it was reported that approximately 146,000 hamsters were used in research in the United States (United States Department of Agriculture, 2010).

Recent Advances in Understanding the Pathogenesis of Lawsonia intracellularis Infections

Proliferative enteropathy is an infectious disease caused by an obligate intracellular bacterium, Lawsonia intracellularis, and characterized by thickening of the intestinal epithelium due to enterocyte proliferation. The disease is endemic in swine herds and has been occasionally reported in various other species. Furthermore, outbreaks among foals began to be reported on breeding farms worldwide within the past 5 years. Cell proliferation is directly associated with bacterial infection and replication in the intestinal epithelium. As a result, mild to severe diarrhea is the major clinical sign described in infected animals. The dynamics of L. intracellularis infection in vitro and in vivo have been well characterized, but little is known about the genetic basis for the pathogenesis or ecology of this organism. The present review focuses on the recent advances regarding the pathogenesis and host-pathogen interaction of L. intracellularis infections.

Shigella in Brazilian children with acute diarrhoea: prevalence, antimicrobial resistance and virulence genes

Diarrhoeal disease is still considered a major cause of morbidity and mortality among children. Among diarrhoeagenic agents, Shigella should be highlighted due to its prevalence and the severity of the associated disease. Here, we assessed Shigella prevalence, drug susceptibility and virulence factors. Faeces from 157 children with diarrhoea who sought treatment at the Children's Hospital João Paulo II, a reference children´s hospital in Belo Horizonte, state of Minas Gerais, Brazil, were cultured and drug susceptibility of the Shigella isolates was determined by the disk diffusion technique. Shigella virulence markers were identified by polymerase chain reaction. The bacterium was recovered from 10.8% of the children (88.2% Shigella sonnei). The ipaH, iuc, sen and ial genes were detected in strains isolated from all shigellosis patients; set1A was only detected in Shigella flexneri. Additionally, patients were infected by Shigella strains of different ial, sat, sen and set1A genotypes. Compared to previous studies, we observed a marked shift in the distribution of species from S. flexneri to S. sonnei and high rates of trimethoprim/sulfamethoxazole resistance.

Platelet-activating factor receptor blockade ameliorates Aggregatibacter actinomycetemcomitans-induced periodontal disease in mice

Periodontal disease (PD) is a chronic inflammatory and alveolar bone destructive disease triggered by oral biofilm-producing microorganisms, such as Aggregatibacter actinomycetemcomitans. The levels of the phospholipid platelet-activating factor (PAF) in the saliva, gingival crevicular fluid, and periodontal tissues are significantly increased during inflammatory conditions, such as PD, but the exact mechanism that links PAF to alveolar bone resorption is not well understood. In the current study, alveolar bone resorption was induced by experimental PD through the oral inoculation of A. actinomycetemcomitans in wild-type (WT) and PAF receptor knockout (Pafr(-/-)) mice. In vitro experiments using A. actinomycetemcomitans lipopolysaccharide (LPS)-stimulated RAW 264.7 cells treated with a PAF receptor antagonist (UK74505) were also performed. The expression of lyso-PAF acetyltransferase in periodontal tissues was significantly increased 3 h after A. actinomycetemcomitans LPS injection in mice. WT and Pafr(-/-) mice that were subjected to oral inoculation of A. actinomycetemcomitans presented neutrophil accumulation and increased levels of CXCL-1 and tumor necrosis factor alpha (TNF-α) in periodontal tissues. However, Pafr(-/-) mice presented less alveolar bone loss than WT mice. The in vitro blockade of the PAF receptor impaired the resorptive activity of A. actinomycetemcomitans LPS-activated osteoclasts. In conclusion, this study shows for the first time that the blockade of PAF receptor may contribute to the progression of PD triggered by A. actinomycetemcomitans by directly affecting the differentiation and activity of osteoclasts.

Diagnosis of liver disease in domestic ferrets (Mustela putorius)

Liver disease in ferrets is often subclinical and underdiagnosed. Clinical pathology and diagnostic imaging are needed to guide clinicians but definite diagnosis is based on histopathologic lesions. Inflammatory digestive conditions can lead to ascending tract infection and hepatobiliary inflammation. Ferrets have a specific sensitivity to hepatic lipidosis. Incidence of hepatic neoplasia is high in ferrets. After a summary of anatomy and physiology of the ferret liver, hepatic diseases known in ferret species are reviewed with their subsequent diagnostic procedures.

Attaching and effacing Escherichia coli and Shiga toxin-producing E. coli in children with acute diarrhoea and controls in Teresina/PI, Brazil

This 3.5-year prospective study was conducted to ascertain the level of attaching and effacing Escherichia coli (AEEC) associated diarrhoea in children from Teresina, a northeastern state of Brazil. Passed faecal specimens from 400 patients (250 with and 150 without diarrhoea) up to 60 months of age attending from 2004 to 2007 at two public hospitals were investigated. Conventional microbiology methods and PCR were employed. Escherichia coli was isolated from 390 children, 240 of them with diarrhoea. A total of 117 AEEC strains were cultivated from specimens from 63 children, 37 with and 26 without diarrhoea. No association between AEEC and diarrhoea was observed. Atypical enteropathogenic E. coli (a-EPEC) (79.4%) was more commonly found than typical EPEC (t-EPEC). Association between EPEC and EPEC subtypes and diarrhoea was not detected. Mixed infection by t-EPEC and a-EPEC and infection by Shiga toxin-producing E. coli (STEC) were rare. Enteropathogenic E. coli was more common in males and in children aged less than 12 months. Correlation between serotyping and PCR results was 0.19. High resistance rates of AEEC to ampicillin, cephalotin, and trimethoprim-sulfamethoxazole were found. In conclusion, EPEC is very common in children with diarrhoea and controls in the population we studied, with a-EPEC predominating. This diarrhoeagenic E. coli (DEC) pathotype is more common in infant males and is resistant to drugs frequently used in clinical practice.

MIF induces osteoclast differentiation and contributes to progression of periodontal disease in mice

Periodontal disease (PD) is a chronic inflammatory and alveolar bone destructive disease triggered by microorganisms from the oral biofilm. Oral inoculation of mice with the periodontopathogen Aggregatibacter actinomycetemcomitans (Aa) induces marked alveolar bone loss and local production of inflammatory mediators, including Macrophage Migration Inhibitory Factor (MIF). The role of MIF for alveolar bone resorption during PD is not known. In the present study, experimental PD was induced in BALB/c wild-type mice (WT) and MIF knockout mice (MIF⁻/⁻) through oral inoculation of Aa. Despite enhanced number of bacteria, MIF⁻/⁻ mice had reduced infiltration of TRAP-positive cells and reduced alveolar bone loss. This was associated with decreased neutrophil accumulation and increased levels of IL-10 in periodontal tissues. TNF-α production was similar in both groups. In vitro, LPS from Aa enhanced osteoclastic activity in a MIF-dependent manner. In conclusion, MIF has role in controlling bacterial growth in the context of PD but contributes more significantly to the progression of bone loss during PD by directly affecting differentiation and activity of osteoclasts.

Chemical composition of Desulfovibrio desulfuricans lipid A

Lipopolysaccharides also called endotoxins are an integral component of the outer membrane of Gram-negative bacteria. When released from the bacterial surface, they interact with a host immune system, triggering excessive inflammatory response. Lipid A is the biologically most active part of endotoxin, and its activity is modulated by the quantity, quality and arrangement of its fatty acids. Desulfovibrio desulfuricans is sulfate-reducing, Gram-negative bacterium that is supposed to be opportunistic pathogens of humans and animals. In the present study, chemical composition of lipid A from various strains of D. desulfuricans was analyzed by gas chromatography/mass spectrometry. It was found that the fatty acid component of the lipid A contains dodecanoic, tetradecanoic, 3-hydroxytetradecanoic and hexadecanoic acids, and its carbohydrate core is composed of glucosamine. The analysis of 3-acyloxyacyl residue of the lipid A revealed the presence of amide-bound 3-(dodecanoyloxy)tetradecanoic and 3-(hexadecanoyloxy)tetradecanoic acids and ester-bound 3-(tetradecanoyloxy)tetradecanoic acid. It was concluded that both fatty acid and 3-acyloxyacyl residue profiles of the lipid A from the studied bacteria were similar to those of E. coli and S.enterica.

Prevalence of Helicobacter pylori vacA, cagA, iceA and oipA genotypes in Tunisian patients

Background

Distinct virulence factors of H. pylori have been described: the vaculating cytotoxin (vacA), the cytotoxin associated gene (cagA), the induced by contact with epithelium factor Antigen (iceA gene) and the outer membrane protein oipA. In Tunisia, there are no data regarding the pattern of H. pylori genotypes; therefore, this prospective and multicentre study was the first to be done in Tunisia and aimed to investigate the prevalence of the vacA, cagA, iceA and oipA genotypes of H. pylori isolates from Tunisian patients with peptic ulceration, gastric cancer, MALT lymphoma and gastritis.

Methods

H. pylori was cultured from endoscopic biopsies obtained from 281 Tunisian patients. The vacA alleles, cagA, iceA and oipA genotypes were determined by PCR.

Results

The vacA s1m1, s1m2 and s2m2 were respectively found in 10.7%, 12.5% and 45.6% of strains. The s2m1 genotype was not detected in our study. The cagA was found in 61.6% of isolates. The iceA1 and the iceA2 genotypes were respectively isolated in 60.2% and in 16% of strains. The oipA genotype was detected in 90.8% of strains. Considering the vacA and iceA genotypes, the presence of multiple H. pylori strains in a single biopsy specimen was found respectively in 31.4% and 23.8%. The comparison between strains isolated from antrum and fundus showed that Tunisian patients were infected with two or more strains of different cagA, vacA, iceA and oipA genotypes and the discordance was respectively in 9.6%, 4.6%, 8.9% and 8.5% of strains.

Conclusion

Our results showed that in 46% (131 strains among 281), the H. pylori strains were highly virulent in relation of the three or four virulent factors they could carry. These finding were described before in the literature. Tunisian patients were colonized by one or multiple strains of H. pylori in the same time in relation of presence of vacA m1/m2 and iceA1/iceA2 in the same biopsy. The discordance between strains isolated from antrum and fundus was high, and it is in favour of multicolonization.

[Inflammatory bowel diseases and enteric microbiota]

Intestinal mucosal layers are colonized by a complex microbiota that provides beneficial effects under normal physiological conditions, but is capable of contributing to chronic inflammatory disease such as inflammatory bowel disease (IBD) in susceptible individuals. Studies have shown that the enteric microbiota may drive the development of the gut immune system and can induce immune homeostasis as well as contribute to the development of IBD although the precise etiology is still unknown. Therefore, intestinal microbes seem to play a key role in the disease pathogenesis. Especially, dysbiosis, which is a shift in the composition of enteric microbiota to a nonphysiologic composition, is associated with one or more defects in mucosal immune functions, including microbe recognition, barrier function, intercellular communication, and anti-microbial effector mechanisms. This review focuses on the impact of enteric microbiota on the development and perpetuation of IBD. In addition, interactions with enteric bacteria and mucosal cells, including intestinal epithelial cells, dendritic cells, and T cells, to induce immune responses at mucosal surfaces have been discussed in the point of IBD pathogenesis. Further extension of the knowledge of enteric microbiota may lead to insights on the pathogenesis and new therapeutic strategies for IBD.

Effects of Helicobacter pylori infection on the expressions of Bax and Bcl-2 in patients with chronic gastritis and gastric cancer

The aim of the present study is to evaluate the influence of Helicobacter pylori on Bax and Bcl-2 mRNA and protein levels in patients with chronic gastritis and gastric cancer. The study included 217 patients, of which 26 were uninfected; 127 had chronic gastritis and were H. pylori-positive, and 64 had gastric cancer. Bacterial genotypes were evaluated by PCR, and the expression values were determined by quantitative real-time PCR and immunohistochemistry. Our data showed that the up-regulationary effects of H. pylori infection on the pro-apoptotic gene, Bax, were stronger than its induction of Bcl-2; this effect may increase apoptosis in patients with chronic gastritis. In patients with gastric cancer, the up-regulation of the anti-apoptotic gene, Bcl-2, counteracted the pro-apoptotic effects of Bax, leading to a deregulation of apoptosis-associated gene expression, favoring cell proliferation. Thus, the disturbance in Bax and Bcl-2 balance, induced by H. pylori, might be important in gastric cancer development.

Bacterial and parasitic diseases of ferrets

The domestic ferret, Mustela putorius furo, is a popular companion animal and is used in biomedical research. When compared with other companion mammals, primary bacterial and parasitic infections are less common in domestic ferrets. In countries such as the United States, pet ferrets are generally kept indoors, and the risk for exposure to primary bacterial and parasitic infectious agents is low. Companion, breeding, and working ferrets are commonly kept outdoors in other parts of the world, placing them at comparatively greater risk for exposure to infectious diseases. This article discusses clinical signs, diagnosis, and treatment of bacterial and parasitic diseases of ferrets.

Intestinal bacteria and inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are the two principal forms of inflammatory bowel disease (IBD). Animal studies show that bacteria are involved in the etiology of IBD, and much is now known about the inflammatory processes associated with CD and UC, as well as the underlying genetic, environmental, and lifestyle issues that can affect an individual's predisposition to these diseases. However, while a number of candidate microorganisms have been put forward as causative factors in IBD, the primary etiologic agents are unknown. This review discusses the potential role of luminal and mucosal microbial communities in the etiology of IBD, and outlines studies that have been made using a variety of biotherapeutic therapies, involving the use of antibiotics, probiotics, prebiotics, and synbiotics.

Effects of Helicobacter infection on research: the case for eradication of Helicobacter from rodent research colonies

Infection of mouse colonies with Helicobacter spp. has become an increasing concern for the research community. Although Helicobacter infection may cause clinical disease, investigators may be unaware that their laboratory mice are infected because the pathology of Helicobacter species is host-dependent and may not be recognized clinically. The effects of Helicobacter infections are not limited to the gastrointestinal system and can affect reproduction, the development of cancers in gastrointestinal organs and remote organs such as the breast, responses to vaccines, and other areas of research. The data we present in this review show clearly that unintentional Helicobacter infection has the potential to significantly interfere with the reliability of research studies based on murine models. Therefore, frequent screening of rodent research colonies for Helicobacter spp. and the eradication of these pathogens should be key goals of the research community.

Influence of Helicobacter pylori infection on the expression of MLH1 and MGMT in patients with chronic gastritis and gastric cancer

The aim of the present study was to evaluate the influence of Helicobacter pylori on MLH1 and MGMT mRNA levels in patients with chronic gastritis and gastric cancer. The study included 217 patients, of which 26 were uninfected, 127 had chronic gastritis and were H. pylori-positive, and 64 had gastric cancer. Bacterial genotypes were evaluated by polymerase chain reaction (PCR), and the expression levels of MLH1 and MGMT were determined by quantitative real-time PCR and immunohistochemistry. There was an association between infection with cagA, vacA s1m1 strains and gastric cancer development. When the gastric epithelium and associated inflammation were examined for expression of MLH1 and MGMT, an overall increase in expression was observed. On the other hand, these levels decrease significantly among gastric cancer patients. The loss of MLH1 and MGMT expression in gastric cancer patients suggests that it is not an early event in H. pylori-associated gastric carcinogenesis.

Infection of different strains of mice with Lawsonia intracellularis derived from rabbit or porcine proliferative enteropathy

This report describes intestinal lesions in five strains of mice infected orally with Lawsonia intracellularis-infected tissue homogenates from rabbits or pigs (RLI and PLI). BALB/cA, C3H/HeJ, C57BL/6J and ICR mice were susceptible to infection with RLI, whereas only C3H/HeJ, C57BL/6J and ICR strains were susceptible to PLI. In susceptible mice, crypt epithelial hyperplasia occurred in association with an inflammatory reaction, as in proliferative enteropathy (PE) in other species. The intestinal changes in the infected mice varied from mild to severe. Unlike rabbit or porcine PE, in which the changes are confined to the ileum, the lesions in mice were located in the caecum. Immunolabelling of L. intracellularis antigen was abundant in early infection when the epithelial hyperplasia was mild or absent. When the hyperplasia had become severe, however, immunolabelling was weak. For this reason, it is suggested that transitory infection of the epithelium induces epithelial hyperplasia. Genetic differences between mouse strains appeared to play an important role in the response to L. intracellularis infection. Moreover, the susceptibility of BALB/cA mice to RLI but not to PLI suggests that there are significant biological differences between L. intracellularis isolates from rabbit PE and porcine PE.

Physiological alterations of a Fusobacterium nucleatum strain exposed to oxidative stress

AIM

The purpose of this study was to investigate the effect of oxidative stress on physiological and genetic characteristics of Fusobacterium nucleatum and its interference on this microbial identification methods.

METHODS AND RESULTS

Fus. nucleatum ssp. nucleatum ATCC 25586 (wt-strain) and an oxidative-stress-adapted strain derived from the wt-strain (aero-strain) were employed in the study. Cell-free crude protein extracts were obtained from both strains and differentially expressed proteins were identified by two-dimensional electrophoresis. Bacterium identification was performed by conventional biochemical tests, automated Rapid ID 32A system and specific PCR analysis. Genetic diversity between wt- and aero-strain was assessed by arbitrarily-primed (AP)-PCR. There were significant changes in the protein profile of aero-strain. The identification of the wt-strain was confirmed by all methods employed. Similar results were obtained for aero-strain when conventional biochemical tests and PCR were used. However, aero-strain was identified as Fusobacterium varium when submitted to Rapid ID 32A system. According to AP-PCR analysis, no significant genetic alteration was detected in aero-strain.

CONCLUSIONS

The adaptive response of Fus. nucleatum to oxidative stress is associated with changes on its biology, which may lead to misidentification of the organism, according to the conventional identification methods.

SIGNIFICANCE AND IMPACT OF THE STUDY

Oxidative stress may act as a cause of adaptive response in Fus. nucleatum with consequences to its biology, such as alterations on biochemical and physiological profile.

Relationship among oxidative DNA damage, gastric mucosal density and the relevance of cagA, vacA and iceA genotypes of Helicobacter pylori

The aim of this study was to evaluate the relationship among oxidative DNA damage, density of Helicobacter pylori and the relevance of cagA, vacA and iceA genotypes of H. pylori. Gastric epithelial cells were isolated from 24 uninfected patients, 42 H. pylori infected patients with gastritis, and 61 patients with gastric cancer. Oxidative DNA damage was analyzed by the Comet assay, the density of H. pylori was measured by real-time polymerase chain reaction (PCR), and allelic variants of cagA, vacA and iceA were identified using the PCR. Infected patients by Helicobacter pylori cagA(+), vacAs1 m1 and iceA1 genotype showed higher levels of oxidative DNA damage than infected patients with H. pylori cagA(-), vacAs2 m2 and iceA2 genotypes and uninfected patients. Density of H. pylori did not influence oxidative DNA damage. Our results indicate that H. pylori genotype is more relevant than density for oxidative DNA damage.

J. Análise das impressões digitais de DNA e de fatores de virulência de linhagens de Helicobacter pylori

RACIONAL: Helicobacter pylori é hoje aceito como o principal agente etiológico de gastrite em seres humanos e fator de risco para úlcera péptica e câncer gástrico. A evolução da infecção está relacionada a diversos fatores, inclusive bacterianos, como presença do gene cagA e o genótipo vacA s1m1, associados ao desenvolvimento de úlcera e adenocarcinoma gástrico. A técnica de RAPD ("random amplified polimorphic") tem sido amplamente utilizada para obtenção de impressões digitais de DNA para examinar a similaridade entre linhagens. OBJETIVOS: Avaliar a presença de cagA e alelos do vacA em amostras de H. pylori e associar os achados com a doença apresentada e também investigar possível clonicidade entre os fatores de virulência e as doenças com a impressão digital de DNA gerada pelo RAPD-PCR. MÉTODOS: Foram incluídas 112 amostras provenientes de pacientes com diferentes laudos endoscópicos: gastrite (n = 41), esofagite de refluxo (n = 14), úlcera gástrica (n = 19) e úlcera duodenal (n = 38). A análise dos fatores de virulência da bactéria foi feita por PCR e as impressões digitais de DNA foram estabelecidas pelo método de RAPD-PCR. RESULTADOS: Os resultados obtidos indicam que houve uma associação significativa entre úlcera duodenal e o mosaico vacA s1m1. Analisando-se os padrões de bandas geradas pelo RAPD-PCR, sete diferentes dendogramas foram construídos e não foi possível detectar associação significativa entre os agrupamentos, sugerindo que as amostras não possuem perfil clonal. CONCLUSÃO: Os resultados reforçam a importância do gene vacA como um marcador de virulência do H. pylori. O RAPD da impressão digital de DNA realizado foi incapaz de associar o padrão de bandas com as enfermidades e os genótipos de vacA e cagA.

Proliferative enteropathy: a global enteric disease of pigs caused byLawsonia intracellularis

Proliferative enteropathy (PE; ileitis) is a common intestinal disease affecting susceptible pigs raised under various management systems around the world. Major developments in the understanding of PE and its causative agent,Lawsonia intracellularis, have occurred that have led to advances in the detection of this disease and methods to control and prevent it. Diagnostic tools that have improved overall detection and early onset of PE in pigs include various serological and molecular-based assays. Histological tests such as immunohistochemistry continue to be the gold standard in confirmingLawsonia-specific lesions in pigspost mortem. Despite extreme difficulties in isolatingL. intracellularis, innovations in the cultivation and the development of pure culture challenge models, have opened doors to better characterization of the pathogenesis of PE throughin vivoandin vitro L. intracellularis–host interactions. Advancements in molecular research such as the genetic sequencing of the entireLawsoniagenome have provided ways to identify various immunogens, metabolic pathways and methods for understanding the epidemiology of this organism. The determinations of immunological responsiveness in pigs to virulent and attenuated isolates ofL. intracellularisand identification of various immunogens have led to progress in vaccine development.

Detection of Lawsonia intracellularis in wild boar and fallow deer bred in one game enclosure in the Czech Republic

The prevalence of Lawsonia intracellularis between wild boar (Sus scrofa) and fallow deer (Dama dama) bred in one game reserve was investigated using the nested PCR method. In the study, 88 clinically healthy wild boars of different age categories and two fallow deer bagged in the game reserve were examined. Lawsonia intracellularis was demonstrated in the mucous membrane of the intestine of eight (9.1%) wild boars and one fallow deer. Of the nine wild boar whose tissues of corresponding lymph nodes were examined in addition to the mucous membrane of the ileum, one tested positive for the microorganism. A relationship between the occurrence of L. intracellularis and age of wild boar was demonstrated. Because wild boar and fallow deer are bred together in one game reserve, the possibility of inter-species transfer of L. intracellularis should be borne in mind.

Actinobacillus actinomycetemcomitansserotype-specific genotypes and periodontal status in Brazilian subjects

Periodontitis is associated with members of the oral microbiota, such as Actinobacillus actino mycetem comitans. To our knowledge, this is the first study to evaluate, by PCR, the occurrence of the six known bacterium serotypes that included subjects with and without periodontitis. Our group comprised 49 Brazilian subjects. We studied 146 bacterial isolates from 23 patients with aggressive or chronic periodontitis and 26 subgingival specimens from subjects with or without periodontitis, all originating in our collection. Serotypes b and c were observed in similar frequencies, and no subject harboured d, e, or f serotype strains. Around 78% subjects had single-serotype infection. Mixed infection was seen only in aggressive periodontitis patients. An association between serotype b and healthy periodontium and between serotype c and chronic periodontitis was observed. Our results diverge from those previously reported, which may be explained by specific distribution patterns in distinct populations. The association of different serotypes with the same periodontal status or conversely of a serotype with different periodontal conditions indicates that organism serotyping should not be used as a sole reliable marker for predicting the outcome of the infection. Evaluation of factors involved in human oral cavity colonization by subsets of A. actinomycetemcomitans is essential for elucidating organism-host-environment relationships.Key words: Actinobacillus actinomycetemcomitans, genotyping, serotyping, periodontitis.

Lawsonia intracellularis Proliferative Enteropathy in a Filly

Proliferative enteropathy (PE) caused by the obligate intracellular bacterium Lawsonia intracellularis is a disease of high economic impact in swine worldwide. In most other species the disease occurs as a sporadic infection. This paper reports a PE caused by L. intracellularis in a 9-month-old Pura Raza Española filly with a history of profuse diarrhoea. Pathological lesions consisted of a severe proliferative enteritis associated with argyrophilic bacteria in the apical cytoplasm of proliferating crypt epithelium. Characteristic PCR products confirmed the presumptive diagnosis of L. intracellularis infection. To our knowledge this is the first report of PE in a horse in Europe caused by L. intracellularis.

Issues to consider for preparing ferrets as research subjects in the laboratory

The domestic or European ferret (Mustela putorius furo) has been domesticated for thousands of years. Ferrets have been used for hunting and fur production, as pets, and as models in biomedical research. Despite the relatively small numbers used in the laboratory, ferrets have some unique applications including study of human influenza and severe acute respiratory syndrome (SARS)-associated corona virus. They have served as models for peptic ulcer disease, carotenoid metabolism, cystic fibrosis, and drug emesis screening, among others. Most research ferrets are males, due to estrus-related health problems in females. They may be housed conventionally and are easy to care for when their biology and behavior are understood. Due to the small number of ferret suppliers, animals are often shipped long distances, requiring air transport and intermediate handlers. It is important to minimize shipment stress, especially with weanling and pregnant animals. Additional expertise is required for success with pregnant and whelping ferrets and for rearing of neonates. The animals have specific dietary requirements, and proper nutrition is key. Successful housing requires knowledge of ferret behaviors including social behavior, eating habits, a general inquisitive nature, and a species-typical need to burrow and hide. Regular handling is necessary to maintain well-being. A ferret health care program consists of physical examination, immunization, clinical pathology, and a working knowledge of common ferret diseases. Various research methodologies have been described, from basic procedures such as blood collection to major invasive survival surgery. Ferrets have a distinct niche in biomedical research and are hardy animals that thrive well in the laboratory.

Use of Comet assay to assess DNA damage in patients infected by Helicobacter pylori: comparisons between visual and image analyses

Studies of DNA damage in gastric epithelial cells of Helicobacter pylori (H. pylori)-infected patients are conflicting, possibly due to different methods used for scoring DNA damage by Comet assay. Therefore, we compared the sensitivity of visual microscopic analysis (arbitrary units-scores and comets%) and image analysis system (tail moment), in the gastric epithelial cells from the antrum and corpus of 122 H. pylori-infected and 32 non-infected patients. The feasibility of cryopreserved peripheral blood lymphocytes and whole-blood cells for DNA damage biomonitoring was also investigated. In the antrum, the levels of DNA damage were significantly higher in H. pylori-infected patients with gastritis than in non-infected patients with normal mucosa, when evaluated by image analysis system, arbitrary units and comets%. In the corpus, the comets% was not sufficiently sensitive to detect the difference between H. pylori-infected patients with gastritis and non-infected patients with normal mucosa. The image analysis system was sensitive enough to detect differences between non-infected patients and H. pylori-infected patients with mild gastritis and between infected patients with moderate and severe gastritis, in both antrum and corpus, while arbitrary units and comets% were unable to detect these differences. In cryopreserved peripheral blood lymphocytes, the levels of DNA damage (tail moment) were significantly higher in H. pylori-infected patients with moderate and severe gastritis than in non-infected patients. Overall, our results indicate that the image analysis system is more sensitive and adequate to measure the levels of DNA damage in gastric epithelial cells than the other methods assayed.

An abundance of Escherichia coli is harbored by the mucosa-associated bacterial flora of interleukin-2-deficient mice

Mice deficient in interleukin-2 are well suited for use as an animal model for inflammatory bowel disease. Raised under specific-pathogen-free conditions, interleukin-2-deficient mice develop an inflammatory bowel disease resembling ulcerative colitis in humans. The finding that colitis was attenuated when the mice were kept under germfree conditions implies that the resident intestinal flora is involved in the pathogenesis of colitis. The present study addresses the composition of the mucosa-associated bacterial flora in colon samples from interleukin-2-deficient mice that developed colitis. This was investigated by comparative 16S ribosomal DNA (rDNA) sequence analysis and fluorescence in situ hybridization using rRNA-targeted fluorescent probes to quantify the bacterial populations of the mucosa-associated flora. The investigations revealed distinct differences in the bacterial composition of the mucosa-associated flora between interleukin-2-deficient mice and healthy controls. Fluorescence in situ hybridization identified up to 10% of the mucosa-associated flora in interleukin-2-deficient mice as Escherichia coli, whereas no E. coli was detected in the mucosa from healthy wild-type mice. This finding was consistent with the results from comparative 16S rDNA analysis. About one-third of the clones analyzed from 16S rDNA libraries of interleukin-2-deficient mice represented Enterobacteriaceae, whereas none of the clones analyzed from the healthy controls harbored 16S rDNA from Enterobacteriaceae. The abundance of E. coli in the colonic mucosa of interleukin-2-deficient mice strongly suggests a participation in the pathogenesis of colitis in the interleukin-2-deficient mouse model for inflammatory bowel disease.

DNA Damage in Patients Infected by Helicobacter pylori

Helicobacter pylori (H. pylori) is considered to predispose carriers to gastric cancer but its role on gastric carcinogenesis is still unknown. The aim of this study was to investigate DNA damage by the comet assay in gastric epithelial cells from antrum and corpus in H. pylori-infected patients with gastritis of different degrees. H. pylori status, gastric histology, and DNA damage were studied in 62 H. pylori-infected and 18 non-infected patients, all of them non-smokers, non-alcoholics, and non-drug users. DNA damage was significantly higher in H. pylori-infected patients presenting gastritis than in non-infected patients with normal mucosa. A direct correlation between the levels of DNA damage and the intensity of gastritis was observed in H. pylori-infected patients. Association between DNA damage and age was also found. The levels of DNA damage were significantly higher in patients older than 50 years than in younger patients with the same degree of gastritis. Our results indicate that H. pylori infection is associated with DNA damage in gastric epithelial cells, which could be a biomarker of risk for gastric cancer in humans.