Campylobacter enteritis

Etiology of Acute Diarrheal Disease and Antimicrobial Susceptibility Pattern in Children Younger Than 5 Years Old in Nepal

Diarrhea is a common cause of morbidity and mortality among children younger than 5 years in developing countries. Children from 3 to 60 months of age were recruited from two hospitals in Nepal- Bharatpur Hospital, Bharatpur, and Kanti Children's Hospital, Kathmandu-in 2006 to 2009. Stool specimens collected from 1,200 children with acute diarrhea (cases) and 1,200 children without diarrhea (control subjects) were examined for a broad range of enteropathogens by standard microbiology, including microscopy, enzyme immunoassay for viral pathogens (adenovirus, astrovirus, and rotavirus) and protozoa (Giardia, Cryptosporidium, and Entamoeba histolytica), as well as by using reverse transcription real-time polymerase for norovirus. Antimicrobial susceptibility testing was performed using the disk diffusion method. Overall, rotavirus (22% versus 2%), norovirus (13% versus 7%), adenovirus (3% versus 0%), Shigella (6% versus 1%), enterotoxigenic Escherichia coli (8% versus 4%), Vibrio (7% versus 0%), and Aeromonas (9% versus 3%) were identified significantly more frequently in cases than control subjects. Campylobacter, Plesiomonas, Salmonella, and diarrheagenic E. coli (enteropathogenic, enteroinvasive, enteroaggregative) were identified in similar proportions in diarrheal and non-diarrheal stools. Campylobacter was resistant to second-generation quinolone drugs (ciprofloxacin and norfloxacin), whereas Vibrio and Shigella were resistant to nalidixic acid and trimethoprim/sulfamethoxazole. This study documents the important role of rotavirus and norovirus in acute diarrhea in children younger than 5 years, followed by the bacteria Shigella, enterotoxigenic E. coli, Vibrio cholera, and Aeromonas. Data on the prevalence and epidemiology of enteropathogens identify potential pathogens for public health interventions, whereas pathogen antibiotic resistance pattern data may provide guidance on choice of therapy in clinical settings.

Diarrheal Mechanisms and the Role of Intestinal Barrier Dysfunction in Campylobacter Infections

Campylobacter enteritis is the most common cause of foodborne bacterial diarrhea in humans. Although various studies have been performed to clarify the pathomechanism in Campylobacter infection, the mechanism itself and bacterial virulence factors are yet not completely understood. The purpose of this chapter is to (i) give an overview on Campylobacter-induced diarrheal mechanisms, (ii) illustrate underlying barrier defects, (iii) explain the role of the mucosal immune response and (iv) weigh preventive and therapeutic approaches. Our present knowledge of pathogenetic and diarrheal mechanisms of Campylobacter jejuni is explained in the first part of this chapter. In the second part, the molecular basis for the Campylobacter-induced barrier dysfunction is compared with that of other species in the Campylobacter genus. The bacteria are capable of overcoming the intestinal epithelial barrier. The invasion into the intestinal mucosa is the initial step of the infection, followed by a second step, the epithelial barrier impairment. The extent of the impairment depends on various factors, including tight junction dysregulation and epithelial apoptosis. The disturbed intestinal epithelium leads to a loss of water and solutes, the leak flux type of diarrhea, and facilitates the uptake of harmful antigens, the leaky gut phenomenon. The barrier dysfunction is accompanied by increased pro-inflammatory cytokine secretion, which is partially responsible for the dysfunction. Moreover, cytokines also mediate ion channel dysregulation (e.g., epithelial sodium channel, ENaC), leading to another diarrheal mechanism, which is sodium malabsorption. Future perspectives of Campylobacter research are the clarification of molecular pathomechanisms and the characterization of therapeutic and preventive compounds to combat and prevent Campylobacter infections.

A One Health approach to prevention, treatment, and control of campylobacteriosis

PURPOSE OF REVIEW

To review recent findings regarding the control and treatment of campylobacteriosis.

RECENT FINDINGS

The application of improved diagnostics has led to an upward shift in the attributable burden of Campylobacter infections, in both the United States and Europe as well as in resource-poor settings. Increased focus has brought a fundamental feature of campylobacteriosis -- the ability to cause relapsing disease back into focus, and expanding data on antimicrobial resistance has lead from a switch in first-line therapy for severe diarrhea from quinolones to azithromycin in most contexts, even as evidence of expanding macrolide resistance emerges.

SUMMARY

Campylobacter spp. infection is a common infection worldwide. Antibiotic-resistant Campylobacter spp. has become an emerging threat with the increase in industrial poultry production, as well as the broad use of antibiotics in both animals and humans.

Travellers' diarrhoea: Impact of TD definition and control group design on study results

BACKGROUND

Travellers' diarrhoea (TD) is a common health problem among visitors to the (sub)tropics. Much research deals with aetiology, prevention, and post-infection sequalae, yet the data may not allow comparisons due to incompatible definitions of TD and No TD control groups.

METHOD

The impact of defining TD and No TD control groups was explored by revisiting our recent data. We set up two TD groups: classical TD i.e. ≥3 loose or liquid stools/day and WHO TD (diarrhoea as defined by the WHO) i.e. any diarrhoea, and four No TD groups by TD definition and timing (no classical/WHO TD during travel, no ongoing classical/WHO TD).

RESULTS

TD was recorded for 37% versus 65% of subjects when using classical versus WHO definitions, respectively; the proportions of the various pathogens proved similar. The strictest criterion for the No TD control group (no WHO TD during travel) yielded pathogens among 61% and the least strict (no ongoing classical TD) among 73% of the travellers; the differences were greatest for enteroaggregative Escherichia coli and Campylobacter.

CONCLUSIONS

Definition of TD and control group design substantially impact on TD study results. The WHO definition yields more cases, but the pathogen selection is similar by both definitions. Design of the No TD control group was found critical: only those remaining asymptomatic throughout the journey should be included.

Antimicrobial therapy of acute diarrhoea: a clinical review

Diarrhoea is one of the most commonly occurring diseases. This article presents a review of the current state of the treatment of acute infectious diarrhoea, as well as of the most important pathogens. The general principles of the therapy of diarrhoea are exemplified, followed by a description of the targeted antimicrobial therapy of the most important bacterial gastrointestinal infections, including salmonellosis, shigellosis and Campylobacter infections, as well as infections with pathogenic Escherichia coli strains, yersiniosis and cholera. Diarrhoea caused by toxigenic Clostridium difficile strains has increased in incidence and in severity. These infections will therefore be described in detail, including important new aspects of treatment. Symptomatic therapy is still the most important component of the treatment of infectious diarrhoea. However, empirical antibiotic therapy should be considered for severely ill patients with a high frequency of stools, fever, bloody diarrhoea, underlying immune deficiency, advanced age or significant comorbidities. Increasing resistance, in particular against fluoroquinolones, must be taken into consideration. Therapy with motility inhibitors is not recommended for Shiga toxin-producing Escherichia coli (STEC) infections, Clostridium difficile infections (CDI), and severe colitis. The macrocyclic antibiotic fidaxomicin can reduce the rate of recurrent disease in CDI. Furthermore, evidence for the benefits of faecal microbiota transplantation as a treatment option for multiple recurrences of CDI is increasing. In conclusion, the treatment of acute diarrhoea is still primarily supportive. General empirical antibiotic therapy for acute diarrhoea is not evidence-based.

First Case Report of Campylobacter volucris Bacteremia in an Immunocompromised Patient

We report a case of Campylobacter volucris bacteremia in an immunocompromised patient with polycythemia vera and alcoholic liver cirrhosis. To our knowledge, this is the first case report in which this organism has been isolated from a human clinical specimen.

Campylobacteremia in stage IV gliosarcoma with bevacizumab treatment

Primary campylobacter enteritis with secondary bacteremia was diagnosed in an immunocompromised patient with stage IV gliosarcoma. She developed mild diarrhea followed by systemic symptoms with transient generalized weakness and fever. She was treated with azithromycin and had a full recovery and without relapse through 2 months of follow-up. Her diagnosis was confirmed by a positive stool culture for Campylobacter sp. and blood culture for Campylobacter jejuni/coli.

Acute and chronic histological changes of the small bowel secondary to C. jejuni infection in a rat model for post-infectious IBS

BACKGROUND

Campylobacter jejuni has been implicated in the pathogenesis of post-infectious irritable bowel syndrome (PI-IBS) in humans, effects which may be because of cytolethal distending toxin (CDT). In this study, we characterized both acute and chronic-phase histological changes of the small bowel in rats exposed to wild-type C. jejuni 81-176, or a strain that does not produce CDT, by using a validated rat model of PI-IBS.

METHODS

Sprague-Dawley rats were given 1.0 × 10(8) CFU of either wild-type C. jejuni 81-176 (C+, PI/C+) or the CDT-negative strain (CDT-), or vehicle alone (Control). Acute-phase rats (C+, CDT-) were euthanized on days 2, 4, 8, 16, and 32. Chronic-phase rats (PI/C+, Control) were euthanized 3 months after clearing the initial infection. Segments of duodenum, jejunum, and ileum were resected and the contents plated for C. jejuni culture, and tissue sections were stained for histology.

RESULTS

We observed preferential infection of the ileum and jejunum by Campylobacter jejuni. Compared with controls, epithelial cell basal membrane ballooning, villous tip disruption, and reduced villous-to-crypt ratios were observed for both C+ and CDT- rats. Villous widening, the only result significantly different in C+ vs. CDT- rats, was greatest at day 4 (134.1 ± 21.12 μm vs. 109.9 ± 10.6 μm for CDT-, P < 0.01). Little or no cellular inflammatory changes were seen during acute C. jejuni infection. Three months after clearing the initial infection, no histological changes remained.

CONCLUSION

Significant histological changes, with the absence of inflammatory cells, are seen in the duodenum, jejunum, and ileum of rats during acute infection with C. jejuni. These changes occurred irrespective of the presence or absence of the CDT toxin.

Campylobacter epidemiology: an aquatic perspective

Members of the genus Campylobacter have established themselves as the most common human gastro-enteric pathogens throughout much of the developed world. The ubiquitous distribution of Campylobacter spp. in animal reservoirs and food products derived thereof make such vehicles primary risk factors in contracting campylobacteriosis. The contamination rates, identification of common pathogenic serotypes and extended survival of Campylobacter in surface waters illustrates the potential, but yet to be quantified, campylobacteriosis risk associated with untreated water. The existence and potential pathogenicity of viable but nonculturable forms of Campylobacter remains a contentious subject. Furthermore, the role of such forms in the epidemiology of Campylobacter related disease and their involvement in the large number of waterborne gastroenteritis outbreaks from which a disease agent cannot be isolated remains to be fully clarified. This article presents a survey of current perspectives with regard to the survival and epidemiology of Campylobacter spp. in natural water systems.

Temperature-dependent phenotypic variation of Campylobacter jejuni lipooligosaccharides

BACKGROUND

Campylobacter jejuni is a major bacterial cause of food-borne enteritis, and its lipooligosaccharide (LOS) plays an initiating role in the development of the autoimmune neuropathy, Guillain-Barré syndrome, by induction of anti-neural cross-reactive antibodies through ganglioside molecular mimicry.

RESULTS

Herein we describe the existence and heterogeneity of multiple LOS forms in C. jejuni strains of human and chicken origin grown at 37 °C and 42 °C, respectively, as determined on sodium dodecyl sulphate-polyacrylamide electrophoresis gels with carbohydrate-specific silver staining and blotting with anti-ganglioside ligands, and confirmed by nuclear magnetic resonance (NMR) spectroscopy. The C. jejuni NCTC 11168 original isolate (11168-O) was compared to its genome-sequenced variant (11168-GS), and both were found to have a lower-M(r) LOS form, which was different in size and structure to the previously characterized higher-M(r) form bearing GM₁ mimicry. The lower-M(r) form production was found to be dependent on the growth temperature as the production of this form increased from ~5%, observed at 37 °C to ~35% at 42 °C. The structure of the lower-M(r) form contained a β-D-Gal-(1→3)-β-D-GalNAc disaccharide moiety which is consistent with the termini of the GM₁, asialo-GM₁, GD₁, GT₁ and GQ₁ gangliosides, however, it did not display GM₁ mimicry as assessed in blotting studies but was shown in NMR to resemble asialo-GM₁. The production of multiple LOS forms and lack of GM1 mimicry was not a result of phase variation in the genes tested of NCTC 11168 and was also observed in most of the human and chicken isolates of C. jejuni tested.

CONCLUSION

The presence of differing amounts of LOS forms at 37 and 42 °C, and the variety of forms observed in different strains, indicate that LOS form variation may play a role in an adaptive mechanism or a stress response of the bacterium during the colonization of different hosts.

Activation of the Campylobacter jejuni FlgSR two-component system is linked to the flagellar export apparatus

Activation of sigma(54)-dependent gene expression essential for formation of flagella in Campylobacter jejuni requires the components of the inner membrane-localized flagellar export apparatus and the FlgSR two-component regulatory system. In this study, we characterized the FlgS sensor kinase and how activation of the protein is linked to the flagellar export apparatus. We found that FlgS is localized to the C. jejuni cytoplasm and that His141 of FlgS is essential for autophosphorylation, phosphorelay to the cognate FlgR response regulator, motility, and expression of sigma(54)-dependent flagellar genes. Mutants with incomplete flagellar export apparatuses produced wild-type levels of FlgS and FlgR, but they were defective for signaling through the FlgSR system. By using genetic approaches, we found that FlgSR activity is linked to and downstream of the flagellar export apparatus in a regulatory cascade that terminates in expression of sigma(54)-dependent flagellar genes. By analyzing defined flhB and fliI mutants of C. jejuni that form flagellar export apparatuses that are secretion incompetent, we determined that formation of the apparatus is required to contribute to the signal sensed by FlgS to terminate in activation of expression of sigma(54)-dependent flagellar genes. Considering that the flagellar export apparatuses of Escherichia coli and Salmonella species influence sigma(28)-dependent flagellar gene expression, our work expands the signaling activity of the apparatuses to include sigma(54)-dependent pathways of C. jejuni and possibly other motile bacteria. This study indicates that these apparatuses have broader functions beyond flagellar protein secretion, including activation of essential two-component regulatory systems required for expression of sigma(54)-dependent flagellar genes.

Restoration of flagellar biosynthesis by varied mutational events in Campylobacter jejuni

Both a complex regulatory cascade involving the FlgSR two-component system and phase variation control expression of sigma(54)-dependent flagellar genes in Campylobacter jejuni. In this study, mutational mechanisms influencing production of the FlgS histidine kinase were discovered. Random non-motile, non-flagellated flgS variants were impaired for growth in the chick intestinal tract. Spontaneous revertants restored for flagellar biosynthesis, gene expression, and motility identified by in vivo and in vitro studies had undergone diverse intragenic and extragenic mutational events relative to flgS. Restorative intragenic events included true phase variation, second-site intragenic reversion, and insertion and deletion of short DNA segments within flgS. In vivo-isolated motile revertants possessed an identical, single extragenic mutation to create a partially constitutively active FlgR protein in the absence of FlgS. Considering that FlgR production is also influenced by phase variation, these new findings suggest that the FlgSR two-component system is unique in that each protein is controlled by phase variation and phosphorylation. In addition, this study highlights the mutational activities of C. jejuni and suggests that the bacterium may possess a repertoire of mutational mechanisms to overcome genetic lesions that impair production of virulence and colonization determinants while lacking a normal mismatch repair system.

Genomic differences between Campylobacter jejuni isolates identify surface membrane and flagellar function gene products potentially important for colonizing the chicken intestine

Campylobacter spp. are one of the leading bacterial etiologic agents of acute human gastroenteritis among industrialized countries. Poultry are implicated as a major source of the organism for human illness; however, the factors involved with colonization of poultry gastrointestinal systems remain unclear. Genomics and proteomics analyses were used to identify differences between poor- versus robust-colonizing Campylobacter jejuni isolates, 11168(GS) and A74/C, respectively. Sequence analyses of subtracted DNA resulted in A74/C-specifc genes similar to a dimethyl sulfoxide reductase, a serine protease, polysaccharide modification proteins, and restriction modification proteins. DNA microarray analyses were performed for comparison of A74/C to the complete genome sequences published for two C. jejuni. A total of 114 genes (7.1%) were determined absent from A74/C relative to those genomes. Additionally, proteomics was completed on both soluble and membrane protein extracts from 11168(GS) and A74/C. Variation in protein expression and physical characteristics such as pI was detected between the two isolates that included the major outer membrane protein, flagella, and aconitate hydratase. Several proteins including cysteine synthase and a Ni/Fe hydrogenase were determined to be differentially present between the two isolates. Finally, DNA hybridization analyses of 19 C. jejuni isolates recovered from chickens and humans worldwide over the past 20 years were performed to determine the distribution of a subset of differentially identified gene sequences.

Shigella toxin and the pathogenesis of shigellosis

Shigella dysenteriae 1 produces a periplasmic protein with multiple toxic effects in vivo and in vitro. These include neurotoxicity, cytotoxicity and enterotoxicity, as well as the ability to inhibit cell-free protein synthesis. The purified toxin is a protein of relative molecular mass (Mr) 64 000. It is composed of one catalytically active A subunit (Mr = 32 000) that inhibits protein synthesis, and a complex of five B monomers (Mr approximately 6500 each). Studies using subunit-specific antibodies demonstrate that the B subunit mediates the binding of toxin to toxin receptors in the cell membrane. In a model system in HeLa cell culture, the surface membrane receptor has been shown to be a glycoprotein, most probably asparagine-linked, and to contain oligomeric beta 1----4 linked N-acetyl-D-glucosamine. Studies with metabolic inhibitors and agents that disrupt the cytoskeleton, and/or alter the pH and function of acidic cytoplasmic vesicles, provide indirect evidence that toxin is transported from the cell surface to the cell interior. This process is probably receptor-mediated endocytosis, since it is also inhibited by amines that prevent receptor-mediated uptake of other ligands in well-characterized systems. The toxic action in the HeLa cell is due to the subsequent inhibition of protein synthesis which results from catalytic inactivation of the 60S ribosomal subunit and the cessation of polypeptide chain elongation. Inhibition of protein synthesis by toxin produced subsequent to bacterial invasion of colonic epithelial cells could explain the destructive lesions found in shigellosis. Although toxin can induce jejunal secretion in animal models, there is at present no clear explanation for the secretory response of the gut mucosa in shigella infection.

Proteomic analyses of a robust versus a poor chicken gastrointestinal colonizing isolate of Campylobacter jejuni

Campylobacter spp. are a significant contributor to the bacterial etiology of acute gastroenteritis in humans. Epidemiological evidence implicates poultry as a major source of the organism for human illness. However, the factors involved in colonization of poultry with Campylobacter spp. remain unclear. Determining colonization-associated factors at the proteome level should facilitate our understanding of Campylobacter spp. contamination of poultry. Therefore, proteomic analyses were utilized to identify expression differences between two Campylobacter jejuni isolates, a robust colonizer A74/C and a poor colonizing strain of the chicken gastrointestinal system designated NCTC 11168-PMSRU. Proteomic analyses by two-dimensional gel electrophoresis revealed the specific expression of an outer membrane-fibronectin binding protein, serine protease, and a putative aminopeptidase in the soluble portion of the robust colonizer A74C. Several proteins including a cysteine synthase and aconitate hydratase were detected specifically in the poor colonizer C. jejuni NCTC 11168-PMSRU isolate. Variation in the amino acid sequences resulting in different isoelectric points and relative mobility of the flagellin and C. jejuni major outer membrane (MOMP) protein were also detected between the two isolates. Western blotting of the bacterial proteins revealed the presence of two flagellin proteins in the poor colonizer versus one in the robust colonizing isolate, but no differences in MOMP. The results demonstrated that proteomics is useful for characterizing phenotypic variation among Campylobacter spp. isolates. Interestingly, different gene products potentially involved in robust colonization of chickens by Campylobacter spp. appear to conform to recently identified expression patterns in Biofilm or agar-adapted isolates.

Explaining unexplained diarrhea and associating risks and infections

Gastrointestinal illnesses are common afflictions. However, knowledge of their etiology is often lacking. Moreover, most cases of infections with reportable enteric pathogens (Campylobacter jejuni, Escherichia coli O157:H7, Salmonella, Shigella, Yersinia, Cryptosporidia and Giardia) have sporadic modes of acquisition, yet control measures are often biased towards mitigation of risks discerned by outbreak analysis. To determine the etiology of unexplained diarrhea it is important to study populations that can be matched to appropriate controls and to couple thorough classic microbiologic evaluation on receipt of specimens with archiving and outgrowth capabilities. Research evaluations should address the potential roles of a broad panel of candidate bacterial pathogens including diarrheagenic E. coli, Listeria monocytogenes, Helicobacters and jejuni Campylobacters, and also apply novel massively parallel sequencing and nucleic acid detection technologies that allow the detection of viral pathogens. To fill voids in our knowledge regarding sources of known enteric pathogens it will be critical to extend case-control studies to assess risk factors and exposures to patients with non-epidemic illnesses and to appropriate controls. By filling these gaps in our knowledge it should be possible to formulate rational prevention mechanisms for human gastrointestinal illnesses.

Molecular Phylogeny of theflaAShort Variable Region AmongCampylobacter jejuniIsolates Collected During an Annual Evaluation of Poultry Flocks in the Southeastern United States

Production and processing samples were collected from eight commercial poultry flocks in the southeastern United States and examined for the presence of Campylobacter spp. In an effort to determine relatedness, recovered isolates were typed using flaA short variable region (SVR) DNA sequence analysis. Six of the eight production flocks tested were Campylobacter positive. In general, multiple Campylobacter flaA SVR types were present within a flock. Additionally, types found within a flock were also recovered from the final processed carcass. However, in two cases, the population of Campylobacter flaA SVR types on the processed carcass differed from those recovered from the production samples. Comparison of subtypes among flocks reared on different farms and during different seasons revealed that subtypes of Campylobacter spp. persisted throughout the year and in different locations. Environmental samples from seven of the eight farms tested were also Campylobacter positive. In one flock, a drag swab of the rearing facility was Campylobacter spp. positive while the flock and the final product were both negative. For the remaining sampling periods, environmental samples were positive for Campylobacter spp. concomitant with recovery of Campylobacter spp. from the chickens. In the remaining six flocks, the majority of environmental isolates recovered possessed flaA SVR types identical to isolates recovered from the birds, while in only one case, a recovered environmental isolate possessed a flaA SVR type that was not related to isolates obtained from the flock. Interpretation of these data suggest that the external environment and the poultry production environment share common subtypes of Campylobacter spp. and that these subtypes can contribute to contamination of the final commercial product.

Occurrence of Campylobacter jejuni in Shiraz, Southwest Iran

OBJECTIVE

To investigate the occurrence of Campylobacter jejuni among other bacterial agents of acute diarrhea.

SUBJECTS AND METHODS

Over a period of 3 months, 114 specimens of acute diarrhea were collected from patients aged 2-58 years referred to Nemazi Hospital, Shiraz, Iran. The samples were tested for bacterial pathogens causing acute diarrhea.

RESULTS

Of the 114 samples, 40 proved to be positive for bacterial enteric pathogens: C. jejuni 11 (9.6%), Salmonella spp.18 (15.8%) and Shigella spp. 11 (9.6%). Maximum prevalence of C. jejuni was observed in patients aged 11-15 years. Significantly more females than males were infected with all diarrheal agents (p <0.05).

CONCLUSION

This study confirmed the presence of C. jejuni as a significant cause of gastroenteritis in Shiraz, Southwest Iran.

Campylobacter spp. subtype analysis using gel-based repetitive extragenic palindromic-PCR discriminates in parallel fashion to flaA short variable region DNA sequence analysis

AIMS

The repetitive extragenic palindromic-PCR (rep-PCR) subtyping technique, which targets repetitive extragenic DNA sequences in a PCR, was optimized for Campylobacter spp. These data were then used for comparison with the established genotyping method of flaA short variable region (SVR) DNA sequence analysis as a tool for molecular epidemiology.

METHODS AND RESULTS

Uprime Dt, Uprime B1 or Uprime RI primers were utilized to generate gel-based fingerprints from a set of 50 Campylobacter spp. isolates recovered from a variety of epidemiological backgrounds and sources. Analysis and phenogram tree construction, using the unweighted pair group method with arithmetic mean, of the generated fingerprints demonstrated that the Uprime Dt primers were effective in providing reproducible patterns (100% typability, 99% reproducibility) and at placing isolates into epidemiological relevant groups. Genetic stability of the rep-PCR Uprime Dt patterns under nonselective, short-term transfer conditions revealed a Pearson's correlation approaching 99%. These same 50 Campylobacter spp. isolates were analysed by flaA SVR DNA sequence analysis to obtain phylogenetic relationships.

CONCLUSIONS

The Uprime Dt primer-generated rep-PCR phenogram was compared with a phenogram generated from flaA SVR DNA sequence analysis of the same isolates. Comparison of the two sets of resulting genomic relationships revealed that both methods segregated isolates into similar groups.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results indicate that rep-PCR analysis performed using the Mo Bio Ultra Clean Microbial Genomic DNA Isolation Kit for DNA isolation and the Uprime DT primer set for amplification is a useful and effective tool for accurate differentiation of Campylobacter spp. for subtyping and epidemiological analyses.

Utility of serum Campylobacter specific antibodies in determining prior Campylobacter infection in neurological disease

Campylobacter jejuni has been implicated in the pathogenesis of Guillain-Barre syndrome (GBS); however, little information exists on the utility of Campylobacter serology in determining recent infection in the patient population. C. jejuni specific antibodies (CAs) were measured in 420 blood donors (controls), 99 patients with recent C. jejuni infection, 34 patients with central nervous system disorders (neurology controls), and 44 patients with peripheral nervous system (PNS) disorders: 18 with GBS, 12 with MND and 14 with chronic inflammatory neuropathies. Elevated CA titres consistent with recent C. jejuni infection were found in six of the 44 patients with PNS disorders (three with GBS, two with neuropathy, and one with MND, only one of whom had a history of recent C. jejuni infection), compared with two of 454 controls (p = 0.00001). Therefore, we conclude that CAs are often raised in patients with PNS disorders who do not have a history of recent C. jejuni gastroenteritis, so Campylobacter serology may be an unreliable marker of recent infection in this patient group.

Natural presence of Campylobacter spp. in various internal organs of commercial broiler breeder hens

Campylobacter are known to cause acute bacterial gastroenteritis in humans. Poultry products have been implicated as a significant source of these infections. Six experiments were performed to determine whether Campylobacter could be isolated naturally from the primary and secondary lymphoid organs, liver/gallbladder, and ceca of commercial broiler breeder hens. Broiler breeder hens were acquired from different commercial sources during the early, middle, and late lay cycles. The birds were euthanatized, defeathered, and aseptically opened. To reduce the possibility of cross-contamination between samples, the thymus, spleen, and liver/gallbladder were aseptically removed prior to removal of the ceca. Individual samples were placed in sterile bags, packed on ice, and transported to the laboratory for evaluation. In this study Campylobacter were found in 11 of 43 thymii, eight of 43 spleens, four of 43 liver/gallbladders, and 30 of 43 ceca. Overall, 28 of 53 isolates from the above samples were Campylobacter coli and 25 of 53 isolates were found to be Campylobacter jejuni.

Effect of oral administration of Butyrivibrio fibrisolvens MDT-1 on experimental enterocolitis in mice

Butyrivibrio fibrisolvens MDT-1, a butyrate-producing strain, was evaluated for use as a probiotic to prevent enterocolitis. Oral administration of the MDT-1 strain (10(9) CFU/dose) alleviated the symptoms of colitis (including body weight loss, diarrhea, bloody stool, organic disorder, and mucosal damage) that are induced in mice drinking water that contains 3.0% dextran sulfate sodium. In addition, myeloperoxidase (MPO) activity levels in colonic tissue were reduced, suggesting that MDT-1 mitigates bowel inflammation. The addition of MDT-1 culture supernatant inhibited the growth of nine clinical isolates of Campylobacter jejuni and Campylobacter coli that could potentially cause enterocolitis. Infection of mice with C. coli 11580-3, one of the isolates inhibited by MDT-1 in vitro, resulted in diarrhea, mucosal damage, increased MPO activity levels in colonic tissue, increased numbers of C. coli in the cecum, and decreased body weight gain. However, administration of MDT-1 to mice, prior to and during C. coli infection, reduced these effects. These results suggest that Campylobacter-induced enterocolitis can be alleviated by using B. fibrisolvens as a probiotic.

Detection of Campylobacter jejuni in various lymphoid organs of broiler breeder hens after oral or intravaginal inoculation

Two studies were conducted to determine whether Campylobacter jejuni could rapidly spread and reside in the internal organs of adult broiler breeder hens. In Study 1, university-housed broiler breeders at 22 wk of age were obtained and placed in individual cages. Each hen was intravaginally inoculated weekly from 23 to 32 wk of age with a characterized strain of C. jejuni. At wk 23, 27, and 32, 4 d postinoculation, the hens were euthanized, defeathered, and aseptically opened. In Study 2, university-housed broiler breeder hens were obtained at 42, 53, and 56 wk of age, placed in individual cages, and inoculated either orally or intravaginally with a characterized strain of C. jejuni. To reduce the possibility of cross-contamination among samples, the thymus, spleen, liver, and gallbladder were aseptically removed, prior to the ceca. In both studies, all samples were individually analyzed. In Study 1, at 23 wk of age, C. jejuni was recovered from 4/7 thymii, 2/7 spleens, 5/7 livers and gallbladders, and 6/7 ceca. At 27 wk of age, C. jejuni was recovered from 1/7 thymii and 1/7 ceca. At 32 wk of age, C. jejuni was recovered from 4/11 thymii, 1/11 livers and gallbladders, and 2/11 ceca. In Study 2, C. jejuni was recovered from 2/6 thymii and 5/6 ceca after oral inoculation and 1/6 spleens, 1/6 livers and gallbladders, and 4/6 ceca after vaginal inoculation of 43-wk-old hens. Campylobacter jejuni was recovered from 2/5 thymii, 3/5 spleens, 3/5 livers and gallbladders, and 2/5 ceca after oral inoculation of 53-wk-old hens and 1/5 thymii and 1/5 livers and gallbladders after vaginal inoculation. Campylobacter jejuni was recovered from 1/4 thymii, 2/4 livers and gallbladders, and 1/4 ceca and was not detected in any vaginally inoculated birds of 57-wk-old hens. This study provides evidence that C. jejuni can reside in the internal organs of broiler breeder hens following oral or intravaginal inoculation.

Campylobacter jejuni infection in broiler chickens

Day-old, straight-run broiler chickens were procured from a hatchery located in the Pacific Northwest. The chickens were subdivided individually into nine groups of 20 chickens. The chickens were tagged, housed in isolation chambers on wire, fed commercial broiler feed, and given water ad libitum. Three isolates of Campylobacter jejuni of poultry origin and one of human origin were tested in this study. Various C. jejuni cultures were inoculated into 9-day-old chickens by crop gavage. Four groups of 20 chickens were inoculated at a dose level of 0.5 ml of 1 x 10(2) colony-forming units (CFU)/ml. The other four groups were inoculated with 0.5 ml of 1 X 10(4) CFU/ml. One group of 20 chickens was kept as an uninoculated control group. Four randomly selected chickens from each of the inoculated and uninoculated groups were necropsied at 5, 12, and 19 days postinoculation (DPI). The C. jejuni was cultured and enumerated from a composite of the upper and midintestine and the cecum. Body weights of all chicken groups at 7 days of age and at 5, 12, and 19 DPI were measured and statistically analyzed. No significant differences were present in the mean body weights (MBWs) of 7-day-old, 5 DPI, and 12 DPI male and female broiler chickens inoculated with C. jejuni at both dose levels compared with uninoculated controls. Differences in MBWs of the male and female broilers at 19 DPI were observed in some of the groups. Results of the C. jejuni culture enumeration mean (CEM) of composite intestine samples at 5 DPI from all inoculated chicken groups, irrespective of the dose level, ranged from (2.5 +/- 5.0) x 10(2) to (2.8 +/- 4.8) x 10(5) CFU/g (mean +/- SD). Results of cecum C. jejuni CEM at 5 DPI inoculated at both dose levels ranged from (2.5 +/- 5.0) x 10(6) to (1 +/- 0.0) x 10(7) CFU/g in all treatment groups irrespective of the dose level. CEM results from the composite intestine samples at 12 and 19 DPI increased by 1 log unit, or sometimes more. Results of cecum C. jejuni CEM at 5 DPI inoculated at both dose levels ranged from (2.5 +/- 5.0) x 10(6) to (1 +/- 0.0) x 10(7) CFU/g in all treatment groups irrespective of the dose level. Increases of 2-5 log units in C. jejuni CEM was present in chicken groups inoculated with 1 X 10(2) CFU of C. jejuni, and a 2- to 3-log increase was present in groups inoculated with a higher dose level of C. jejuni at 12 DPI. The results of C. jejuni CEM from cecal samples at 19 DPI were similar to chicken groups at 12 DPI. Campylobacterjejuni was not isolated from the uninoculated control chickens at 5, 12, and 19 DPI. Clinical signs of illness or gross pathologic lesions were not present in any of the chicken groups during this study. No lesions were present on histopathologic evaluations in C. jejuni-inoculated chickens or uninoculated control chickens.

Reactive arthritis

ReA consists of sterile axial or peripheral articular inflammation,enthesitis, and extra-articular manifestations. Most patients are HLA-B27 positive, although determining the B27 status of an individual patient is irrelevant. Exposure to specific bacterial antigens is usually the inciting factor. Diagnosis usually can be made by clinical examination and history. The current standard therapy is NSAIDs and physiotherapy, but molecular biologic treatment may ultimately become the mainstay in recalcitrant and severe ReA.

Campylobacter vaccine development:a key to controlling enteric diseases

Worldwide, Campylobacter jejuni is a major cause of diarrhoea and dysentery, with approximately 400 million cases occurring annually. Control of the disease through public health and antibiotic measures is insufficient, and vaccination offers the most promising solution. Infection produces immunity from disease, suggesting that vaccination may produce similar protection. Epidemiological data suggest that there are conserved antigens among serotypes; immunity against which protects against disease. Therefore a monovalent serotype vaccine seems practical. Several antigens on Campylobacter have been found to be immunogenic and, in some cases, associated with virulence. However, none of these proteins have been produced recombinantly in the proper conformation, nor have they been protective in preclinical models. For this reason, live attenuated or inactivated Campylobacter whole cell (CWC) vaccines may be the best approach. Development of an attenuated strain of Campylobacter has been complicated by the fact that the organism is highly transformable. Rec A mutants of Campylobacter have recently been constructed in an attempt to avoid this trait. Such mutants have been made defective in various virulence properties and are being evaluated for safety in preclinical models. Antex Biologics has made an inactivated CWC vaccine using the Company's patented NST (nutriment signal transduction) technology, whereby the cells are grown using physiologically logical conditions to maximise the expression of antigens associated with in vivo virulence. This vaccine has been shown to be safe, immunogenic, and protective in preclinical models of infection. Inclusion of a mucosal adjuvant in the vaccine increases the immunological response to the antigen. Recent Phase I and Phase II clinical trials, using the CWC vaccine formulated with an adjuvant and orally administered, show that the vaccine is safe and immunogenic in human volunteers. The approach used to develop this inactivated whole cell Campylobacter vaccine is also applicable for the rapid development of new vaccines against a variety of mucosal pathogens.

Prevalence and clonal diversity of Campylobacter jejuni from dairy farms and urban sources

AIM

To investigate the role of free-living animals such as sparrows, rodents and flies as potential reservoirs of Campylobacter spp on a dairy farm, and to assess the genetic diversity among Campylobacter isolates from the farm and an urban source.

METHODS

A total of 290 samples (bovine, passerine and rodent faeces, and whole flies) were collected from a large commercial dairy farm in the Manawatu district in New Zealand, and from faeces from urban sparrows in a nearby city. Other samples collected from the dairy farm included five from silage, two from aprons worn by workers during milking, two from workers' boots and two from water in troughs in a paddock. Isolates of thermophilic Campylobacter spp were identified morphologically and phenotypically and further characterised molecularly using pulsed-field gel electrophoresis (PFGE) and the restriction enzyme SmaI.

RESULTS

Campylobacter jejuni was the only Campylobacter species isolated from all samples. The highest prevalence was found in faeces from dairy cows (54%), followed by faeces from sparrows from the urban area (40%) and the farm (38%), and from rodents (11%) and whole flies (9%). Other samples from the farm environment such as silage, trough water, and workers' aprons and boots were also positive for C. jejuni. Of the 22 restriction patterns obtained, seven were common to more than one source.

CONCLUSIONS

Cattle, sparrows, rodents and flies are potential reservoirs of C. jejuni on dairy farms. Identical clones of C. jejuni carried by cattle, sparrows, flies and rodents probably indicate a common source of infection. The high level of asymptomatic carriage of C. jejuni by healthy dairy cows could be sufficient to maintain infections within the dairy farm surroundings via environmental contamination.

Relationship of Campylobacter isolated from poultry and from darkling beetles in New Zealand

Campylobacter, a foodborne pathogen closely associated with poultry, is considered to be an important agent of human gastroenteritis in New Zealand. The pathways involved in the contamination of poultry flocks remain unclear; however, many vectors, such as insects, rodents, and wild birds, have been implicated. Infestation of poultry houses by insects, particularly darkling beetles (Alphitobius diaperinus), is difficult to control. Furthermore, darkling beetles are known vectors for a variety of pathogens that include Salmonella, infectious bursal disease virus, Aspergillus, Escherichia coli, and Marek's disease virus. In this investigation, the relationship between darkling beetles and Campylobacter contamination of poultry flocks was investigated. A New Zealand breeder flock and four of its progeny broiler flocks were included in the study. Samples of beetles and of intestinal excreta of the birds were cultured for the presence of Campylobacter spp. A subset of the recovered isolates was subsequently genotyped using flaA short variable region (SVR) DNA sequence analysis. A large number of Campylobacter subtypes were isolated, indicating that Campylobacter colonization of poultry is likely to arise from a number of different reservoirs. However, a set of genetically distinct isolates were found to be common to the broiler flocks and to the beetles. This research provides data that indicates that Alphitobius diaperinus may serve as a source of Campylobacter contamination of poultry. A more thorough understanding of the relationship between beetle infestation and the Campylobacter status of poultry flocks should enable progress in further development of biosecurity control measures.

Genotype analyses of Campylobacter isolated from the gastrointestinal tracts and the reproductive tracts of broiler breeder roosters

Campylobacter is considered to be the leading bacterial etiologic agent of acute gastroenteritis in humans. Evidence implicates poultry as a major source of the organism for human illness; however, the pathways involved in Campylobacter contamination of poultry flocks, horizontal transmission and/or vertical transmission, remain unclear. Recent evidence implicates breeders as a potential source for Campylobacter contamination of the subsequent broiler offspring. In this investigation, Campylobacter isolated from feces, cloacal swabs, ceca, semen, and vas deferens of 12 breeder broiler roosters were genotyped by both flagellin A short variable region (flaA SVR) DNA sequence analysis and repetitive element (rep)-polymerase chain reaction (PCR). In 9 of 12 roosters, Campylobacter was isolated from multiple sites sampled. Comparison of multiple isolates obtained from individual roosters revealed variable results. In five of the nine roosters, all Campylobacter isolated demonstrated closely related flaA SVR DNA sequences as well as rep-PCR patterns; isolates from these roosters were collected from both the gastrointestinal and the reproductive tracts or from the gastrointestinal tract alone. The remaining four roosters had Campylobacter that were distinct by both typing methods. Isolates from two of these four roosters originated from both the gastrointestinal and the reproductive tracts. Isolates from the remaining two roosters originated from only the reproductive tract. Comparisons of all Campylobacter isolates recovered from a distinct sample type within either the reproductive tract or the gastrointestinal tract (feces, semen, cloaca, vas deferens, or ceca) were quite diverse. No relationship between the genotypes and the sample type could be ascertained. Further investigation is needed to determine the route of contamination and if the presence of Campylobacter within the rooster leads to contamination of the broiler offspring via the fertilized egg.

Prevalence of Campylobacter concisus in diarrhoea of immunocompromised patients

The importance of Campylobacter species other than C. jejuni/coli in diarrhoeal disease is largely unknown. We wished to determine the prevalence and clinical presentation of C. concisus infection in patients with enteric disease in a tertiary hospital. Stool specimens were routinely tested for the presence of Campylobacter species, by use of the filter isolation method. The medical records of the C. concisus-positive patients were reviewed. Of 224 Campylobacter isolates obtained, 110 were identified as C. concisus. Concomitant infection occurred in only 27% of cases. By means of protein profiling we assigned C. concisus into 2 groups. The predominant C. concisus group 2 was the only strain to infect immunocompetent patients and children: 71% of the infected patients were immunocompromised, the majority being adults (84%). C. concisus may be a frequent cause of diarrhoea in immunocompromised patients. Two groups of C. concisus were found and these groups possibly vary in their pathogenic potential.

Molecular subtype analyses of Campylobacter spp. from Arkansas and California poultry operations

Campylobacter isolates from diverse samples within broiler production and processing environments were typed by using flaA short variable region DNA sequence analysis. Sixteen flocks from four different farms representing two broiler producers in Arkansas and California were analyzed. Fourteen of the flocks (87.5%) were Campylobacter-positive; two remained negative throughout the 6-week rearing period. In general, multiple clones were present within a flock. Additionally, clones found within a flock were also present on the final product, although the diversity of Campylobacter spp. on the final product appeared to be reduced relative to that observed within the flock. Comparison of clones between flocks on the same farm revealed that some clones of Campylobacter persisted in multiple flocks. Furthermore, some clones were identified across the two farms that were under the same management. In two sampling periods, environmental isolates were positive for Campylobacter prior to flock shedding. Environmental samples associated with five additional flocks were positive for Campylobacter concomitantly with recovery of Campylobacter from the birds. Analysis of the environmental isolates that were positive prior to flock shedding demonstrated that in some instances the environmental isolates possessed genotypes identical to those of isolates originating from the flock, while in other cases the environmental isolates possessed genotypes that were distantly related to isolates obtained from the flock. Analyses of environmental isolates that tested positive concurrently with the positive isolates from the flocks demonstrated varied results; in some instances the environmental isolates possessed genotypes identical to those of isolates originating from the flock, while in other cases the environmental isolates possessed genotypes that were distantly related to isolates obtained from the flock. These data suggest that the external environment may contribute to Campylobacter contamination during poultry production and processing. However, environmental contamination with Campylobacter does not appear to be the sole contributing factor.

Ciprofloxacin resistance in Campylobacter jejuni: case-case analysis as a tool for elucidating risks at home and abroad

OBJECTIVE

To determine factors independently associated with the acquisition of a ciprofloxacin-resistant Campylobacter jejuni infection.

METHODS

Self-completion questionnaires were used to collect clinical, demographic and exposure data from cases of campylobacter infection reported to a sentinel surveillance scheme in England and Wales. Isolates from those cases were referred to the Public Health Laboratory Service Campylobacter Reference Unit for speciation, subtyping and antimicrobial resistance testing. Cases infected with a ciprofloxacin-resistant C. jejuni were compared with cases infected with a sensitive strain using case-case analysis. Single risk variable analysis and logistic regression analysis were employed. The analysis was restricted by travel status to control for the confounding effect of foreign travel.

RESULTS AND CONCLUSION

Over half (55%) of the campylobacter infections acquired abroad were resistant to ciprofloxacin, compared with 10% of UK-acquired strains [relative risk 5.23; 95% confidence interval (CI) 4.58-5.96]. For travel-associated cases, ciprofloxacin-resistant infections were independently associated with travel to Spain [odds ratio (OR) 6.87; 95% CI 3.52-13.38], Portugal (OR 22.40; 95% CI 4.36-114.99) or Cyprus (OR 11.74; 95% CI 1.28-108.02), and the consumption of chicken (OR 4.95; 95% CI 2.12-11.56) or bottled water (OR 3.70; 95% CI 1.69-8.10). Indigenous cases infected with a ciprofloxacin-resistant strain were more likely to report the consumption of pre-cooked cold meats (OR 2.13; 95% CI 1.44-3.13). The risk of acquiring a ciprofloxacin-resistant campylobacter infection was strongly associated with foreign travel. Restricting the analyses by travel status revealed different sets of risk exposures for acquiring a resistant C. jejuni strain, suggesting that different intervention strategies will be required.

Identification of a New Source of Campylobacter Contamination in Poultry: Transmission from Breeder Hens to Broiler Chickens

Campylobacter jejuni, a foodborne pathogen closely associated with market poultry, is considered to be the most frequent agent of human gastroenteritis in the United States. The pathways involved in the contamination of poultry flocks, vertical transmission and/or horizontal transmission, are unclear. In this study, Campylobacter isolates from two independent commercial broiler breeder flocks, as well as from their respective progeny, were characterized and compared by PstI ribotype analysis and by DNA sequence analysis of the short variable region (SVR) of the flaA gene (flaA SVR). Campylobacter isolates originating from one set of breeder hens and the feces from their respective progeny demonstrated identical ribotype patterns as well as identical flaA SVR DNA sequences, thereby suggesting that these isolates were clonal in origin. Ribotype analysis of Campylobacter isolates from the second set of breeder hens and processed carcasses from their offspring resulted in two patterns. Sequence analysis placed these isolates into two closely related groups and one distant group, similar to the ribotype analysis. These results demonstrate that Campylobacter isolates from commercial broiler breeder flocks and from the respective broiler progeny may be of clonal origin and that breeder hens can serve as a source for Campylobacter contamination in poultry flocks.

Direct polymerase chain reaction detection of Campylobacter spp. in poultry hatchery samples

A rapid, sensitive, and specific polymerase chain reaction (PCR) assay was developed for the direct detection of Campylobacter in environmental samples from hatcheries. PCR, with a set of primers specific for the Campylobacter flaA short variable region (SVR), detected the presence of Campylobacter in both fluff and eggshell samples; however, a determination of whether the organism was living or dead could not be made. Conventional cultural methods detected no Campylobacter from the same samples. An additional benefit of the direct PCR assay is it allows for the production of a product that can be sequenced to provide further epidemiologic information.

Coinfection of enteric Helicobacter spp. and Campylobacter spp. in cats

During a 6-year period, 64 of 227 commercially reared cats had microaerobic bacteria isolated from their feces. All the isolates were initially identified as Campylobacter-like organisms based on biochemical and phenotypic characteristics. DNA extractions from 51 of these isolates were subjected to PCR using primers specific for Helicobacter spp. and Campylobacter spp. Of the isolates, 92% (47 of 51 isolates) were positive for Campylobacter spp., 41% (21 of 51 isolates) were positive for Helicobacter spp., 33% (17 of 51 isolates) were positive for both genera, 59% (30 of 51 isolates) were positive only for Campylobacter spp., and 8% (4 of 51) were positive only for Helicobacter spp. Sixteen of the 47 Campylobacter-positive cultures were positive for more than one Campylobacter spp. Based on a species-specific PCR assay, 83% of the isolates were identified as Campylobacter helveticus, 47% of the isolates were identified as Campylobacter upsaliensis, and 6% of the isolates were classified as Campylobacter jejuni. The 1.2-kb PCR products of the 16S rRNA genes of 19 Helicobacter species isolates were subjected to restriction fragment length polymorphism (RFLP) analysis. Of the five different RFLP patterns obtained, two clustered with Helicobacter ("Flexispira") taxon 8, one clustered with Helicobacter bilis, one clustered with Helicobacter canis, and the remaining pattern was closely related to a novel Helicobacter sp. strain isolated from a woodchuck. The sequence data for the 16S rRNA genes of 10 Helicobacter spp. validated the RFLP-based identification of these isolates. This study demonstrated that biochemical and phenotypic characteristics of microaerobic organisms in cat feces were insufficient to characterize mixed Helicobacter and Campylobacter infections. Molecular structure-based diagnostics using genus- and species-specific PCR, RFLP analysis, and 16S rRNA sequence analysis enabled the identification of multiple microaerobic species in individual animals. The clinical relevance of enteric Helicobacter and Campylobacter coinfection in cats will require further studies.

An integron cassette carrying dfr1 with 90-bp repeat sequences located on the chromosome of trimethoprim-resistant isolates of Campylobacter jejuni

The frequent occurrence of high-level trimethoprim resistance in clinical isolates of Campylobacter jejuni was shown to be related to the acquisition of foreign resistance genes (dfrl or dfr9 or both) coding for resistant variants of the enzyme dihydrofolate reductase, the target of trimethoprim. The dfr1 gene detected on the chromosome of 40 different clinical strains of C. jejuni was studied further regarding structure and genetic organization. Most of the dfr1 genes were found as integron cassettes inserted in the chromosome. In 36% of the examined isolated, the dfr1 gene showed identity to that previously characterized in trimethoprim-resistant Escherichia coli. In 40% of the cases, however, a variant of the dfr1 gene containing a 90-bp direct repeat was detected, and in 5% of the isolates, the repeat-containing dfr1 variant was found to occur in the form of two cassettes in tandem in an integron context. The existence of the 90-bp repeat within the coding sequence of the dfr1gene was found to play a role in the adaptation of C. jejuni to ambient concentrations of trimethoprim.

Diarrhea in children under 5 years of age from Ifakara, Tanzania: a case-control study

A matched case-control study was conducted in the Maternal and Child Health Clinic (MCH) in Ifakara, Tanzania, during the rainy season in order to elucidate the risk factors for and etiology of diarrheal diseases in children under 5 years of age. Cases (103) and controls (206) were matched for sex and age group. Precoded questionnaires with demographic details, clinical history, and physical signs were completed. Stools samples were collected for bacterial, parasitological, and viral studies. A high number of siblings (odds ratio [OR], 0.86; P = 0.027), the number of siblings surviving (OR, 0.82; P = 0.007), the birth order (OR, 0.85; P = 0.018) and the distance from the house to the water source (OR, 0.33; P = 0.011) were associated with the risk of diarrhea. There were high rates of enteropathogen isolates in stool samples from children without diarrhea (52.23%). Shigella species were the only enteropathogen statistically related with diarrhea (OR, 2.90; P < 0.029). Enterotoxigenic, enteropathogenic, and enteroaggregative strains of Escherichia coli were not related with diarrhea, and neither were Giardia lamblia or Salmonella species.

The galE gene of Campylobacter jejuni is involved in lipopolysaccharide synthesis and virulence

Lipopolysaccharide (LPS) is one of the main virulence factors of gram-negative bacteria. The LPS from Campylobacter spp. has endotoxic properties and has been shown to play a role in adhesion. We previously cloned a gene cluster (wla) which is involved in the synthesis of the Campylobacter jejuni 81116 LPS molecule. Sequence alignment of the first gene in this cluster indicated similarity with galE genes. These genes encode a UDP-glucose 4-epimerase, which catalyzes the interconversion of UDP-galactose and UDP-glucose. A Salmonella galE mutant was transformed with the galE gene from C. jejuni. The LPS analysis of wild-type, galE, and complemented galE Salmonella strains showed that the C. jejuni galE gene could restore the smooth wild-type Salmonella LPS. A UDP-glucose 4-epimerase assay was used to demonstrate that the galE gene from C. jejuni encoded this epimerase. We constructed a C. jejuni galE mutant which expressed a lipid A-core molecule of reduced molecular weight that did not react with antiserum raised against the parental strain. These results show an essential role for the galE gene in the synthesis of C. jejuni LPS. The galE mutant also showed a reduction in its ability to adhere to and invade INT407 cells. However, it was still able to colonize chickens to the same level as the wild-type strain. The serum resistance and hemolytic activity of this mutant were not changed compared to the parent strain. The ability of the mutant to take up DNA and integrate it in its genome was reduced 20-fold. These results show that LPS of C. jejuni is an important virulence factor.

Campylobacter species in health, gingivitis, and periodontitis

At least seven Campylobacter species have been identified from subgingival sites. Campylobacter rectus has been implicated as a periodontal pathogen; however, association with periodontal infections of other Campylobacter species, especially the newly described Campylobacter showae, is unclear. This study examined which Campylobacter species were associated with periodontal health and disease. Subgingival Campylobacter species from initial and established periodontitis were compared with species from periodontally healthy subjects, including subjects with gingivitis. Campylobacter species were isolated on selective media and identified by whole-cell protein profiles (SDS-PAGE). Except for C. rectus, Campylobacter levels were frequently below the detection limit (2-5% of the microbiota) of non-selective culture methods. C. rectus and C. showae, including Campylobacter X, were found more frequently and in higher levels from diseased than from healthy periodontal sites. C. gracilis was the dominant Campylobacter species found in relatively shallow pockets; however, its presence was unrelated to periodontal health or disease. C. concisus was isolated in higher proportions from relatively shallow and healthy sites, compared with deeper pockets. C. curvus was unrelated to periodontal health or disease. Analysis of the study data confirmed the relationship of C. rectus with diseased subgingival sites and indicated that C. showae may also be associated with periodontal disease.

Isolation of Campylobacter species from zoo animals and polymerase chain reaction-based random amplified polymorphism DNA analysis

A total of 104 fecal specimens from 30 mammals, 12 birds, and 3 reptiles at the Phoenix Zoological Gardens, Miyazaki City, Japan, were examined for the presence of Campylobacter species. All the animals examined were healthy with no fecal abnormality. Twenty-three (22.1%) thermophilic campylobacters, (9 C. jejuni, 11 C. hyointestinalis, 2 C. coli, and 1 C. lari), were isolated from 11 animals (7 mammals and 4 birds). C. jejuni and C. hyointestinalis were the predominant species isolated from these zoo animals and C. hyointestinalis was isolated frequently from simians. As selective media influence the numbers and species of campylobacters isolated, the agar medium was not supplemented with cephalothin. Campylobacters were isolated most frequently when a combination of enrichment culture and selective agar plating was performed at 42 degrees C. For the epidemiological study, a polymerase chain reaction (PCR)-based randomly amplified polymorphic DNA (RAPD) method was used as a tool to detect the heterogeneity of amplified DNAs of Campylobacter spp. isolated from zoo animals. The two arbitrary primers used in this study enabled even closely related strains of the same Campylobacter spp. to be differentiated. RAPD analysis revealed considerable diversity among the strains, suggesting that the transmission of Campylobacter spp. among animals in a defined area occurred through different mechanisms. Examination of the genotypic diversity among the multiple clones from the same host also revealed differences between clones. These results demonstrate that campylobacter populations in zoo animals are highly divergent.

Frequency of isolation of Campylobacter from roasted chicken samples from Mexico City

The presence of Campylobacter spp. was investigated in 100 samples of roasted chicken tacos sold in well-established commercial outlets and semisettled street stands in Mexico City. From 600 colonies displaying Campylobacter morphology only 123 isolates were positive. From these isolates, 51 (41%) were identified as C. jejuni, 23 (19%) as C. coli, and 49 (40%) as other species of this genus. All of the 27 positive samples came from one location where handling practices allowed cross-contamination of the cooked product. The results indicate that these ready-to-consume products are contaminated with these bacteria, representing a potential risk for consumers, especially in establishments lacking adequate sanitary measures to prevent cross-contamination.