Jejuni Cells Research Articles

Cover Caption

On the cover: SEM photograph showing the characteristic spiral, or corkscrew, shape of Campylobacter jejuni cells and related structures. Image courtesy USDA‐ARS. Photo by De Wood; digital colorization by Chris Pooley.

Effect of temperature and contact time on Campylobacter jejuni attachment to, and probability of detachment from, stainless steel.

The effect of temperature and contact time on attachment of six Campylobacter jejuni strains to, and probability of their detachment from, stainless steel were determined. Triplicate stainless steel coupons (SSC) were exposed to C. jejuni cell suspensions at 4, 25, 37, and 55 degrees C for 30 min. An increase in temperature enhanced the numbers of cells of all strains of C. jejuni attaching to stainless steel from approximately 4 log/cm(2) at 4 degrees C to approximately 5 log/cm(2) at 55 degrees C. Cells attached to SSC at 4 and 25 degrees C for 30 min were detached by the successive blotting technique on a series of Campylobacter blood-free selective agar plates. The probability of detachment was significantly (P < 0.05) higher at 4 degrees C (> or = 0.219) than at 25 degrees C (> or = 0.111) for five of the six strains tested, suggesting the strength of attachment was weaker at 4 degrees C than at 25 degrees C for these strains. C. jejuni cells were allowed to attach to SSC at 4 degrees C for 1, 15, 30, 45, 60, 120, 180, 240, and 300 min. The numbers of cells attaching to SSC reached approximately 4 log/cm(2) after 1 min of contact and increased slowly thereafter to approximately 5 log/cm(2) after 300 min of contact. The probability of detachment significantly (P < 0.05) decreased from 0.443 after 1 min to 0.134 after 240 min of contact, indicating bacterial attachment was strengthened over time. These data suggest that to reduce the numbers of adhered cells on processing surfaces, low-temperature and early bacterial detachment procedures should be applied.

Exposure of Campylobacter jejuni to 6°C: Effects on Heat Resistance and Electron Transport Activity

Human infection with Campylobacter jejuni is frequently associated with the consumption of foods, especially chicken meat, which have been exposed to a range of temperatures during processing, storage, and cooking. Despite the public health importance of C. jejuni, little is known about the effects of cold exposure (refrigeration) on the subsequent ability of this pathogen to survive heat challenge. This work examined the effect of rapid exposure to 6 degrees C for 24 h on the heat resistance at 52 degrees C of 19 C. jejuni strains originally isolated from various sources. The resulting death curves were analyzed with the Weibull model. Unlike cold-exposed cells of Escherichia coli and Salmonella, which have been reported to show significant increased sensitivity to heat, such exposure had only a marginal effect on heat resistance of the C. jejuni strains in this study. A possible explanation for this effect is that rapid chilling renders C. jejuni cells unable to adapt to reduced temperatures in an active manner. This hypothesis is supported by the observation that exposure to 6 degrees C for 24 h resulted in a significant and marked reduction in electron transport system activity when compared with controls at 37 degrees C.

Survival of lactic acid and chlorine dioxide treated Campylobacter jejuni under suboptimal conditions of pH, temperature and modified atmosphere

As mild decontamination treatments are gaining more and more interest due to increased consumer demands for fresh foods, it is of great importance to establish the influence of decontamination treatments on the subsequent bacterial behaviour under suboptimal storage conditions. For this purpose Campylobacter jejuni cells treated with lactic acid (LA, 3% lactic acid, pH 4.0, 2 min) or chlorine dioxide (ClO 2, 20 ppm, 2 min) were inoculated in Bolton broth (pH 6.0) and incubated under 80% O 2/20% N 2, 80% CO 2/20% N 2, air or micro-aerophilic (10% CO 2/85% N 2/5% O 2) atmosphere, at 4 °C during 7 days. Treatment with water served as a control. The most suppressive atmosphere for the survival of C. jejuni was O 2-rich atmosphere, followed by air, micro-aerophilic and CO 2-rich atmosphere. The survival of C. jejuni was dependent on the type of initial decontamination treatment, with water treated cells showing the greatest survival followed by LA and ClO 2 treated cells. Intracellular pH (pH i ) of individual C. jejuni cells was determined using Fluorescence Ratio Imaging Microscopy (FRIM). At all tested conditions, different subpopulation of the cells could be distinguished based on their pH i values. The pH i response was independent on the surrounding atmosphere since similar distribution of the subpopulations was observed for all tested atmospheres. However, the pH i response was dependent on the initial decontamination treatment. The investigation of intracellular parameters gave an insight into pathogen behaviour under stressful conditions at intracellular level. The results obtained in this study highlighted the importance of combining decontamination technologies with subsequent preservation techniques to the control survival and growth of foodborne pathogens.

Identification and characterization of the aspartate chemosensory receptor of Campylobacter jejuni

Summary Campylobacter jejuni is a highly motile bacterium that responds via chemotaxis to environmental stimuli to migrate towards favourable conditions. Previous in silico analysis of the C. jejuni strain NCTC11168 genome sequence identified 10 open reading frames, tlp1‐10, that encode putative chemosensory receptors. We describe the characterization of the role and specificity of the Tlp1 chemoreceptor (Cj1506c). In vitro and in vivo models were used to determine if Tlp1 had a role in host colonization. The tlp1‐ isogenic mutant was more adherent in cell culture, however, showed reduced colonization ability in chickens. Specific interactions between the purified sensory domain of Tlp1 and l‐aspartate were identified using an amino acid array and saturation transfer difference nuclear magnetic resonance spectroscopy. Chemotaxis assays showed differences between migration of wild‐type C. jejuni cells and that of a tlp1‐ isogenic mutant, specifically towards aspartate. Furthermore, using yeast two‐hybrid and three‐hybrid systems for analysis of protein–protein interactions, the cytoplasmic signalling domain of Tlp1 was found to preferentially interact with CheV, rather than the CheW homologue of the chemotaxis signalling pathway; this interaction was confirmed using immune precipitation assays. This is the first identification of an aspartate receptor in bacteria other than Escherichia coli and Salmonella enterica serovar Typhimurium.

Resistance of Campylobacter jejuni to heat and to pulsed electric fields

Abstract The resistance of Campylobacter jejuni NCTC 11351 to heat and to pulsed electric fields (PEF) was studied at different treatment intensities (temperatures between 52 and 60 °C, and electric field strengths between 15 and 35 kV/cm, respectively). The influence of the growth phase, the pH of the treatment medium and the presence of sodium pyruvate in the recovery medium was also examined. A model based on the Weibull distribution was used to describe the inactivation curves, and times for the first decimal reduction were calculated (δ values). C. jejuni cells did not increase their resistance to heat nor to PEF upon entrance into stationary phase. The acidification of the treatment medium from 7.0 to 4.5 caused a sensitization of C. jejuni to heat (δ value at 55 °C × 1/4); on the contrary, resistance to PEF was increased (δ value at 25 kV/cm × 2.5). The absence of pyruvate in the recovery medium prevented recovery of a high percentage of heat-treated cells, but did not affect PEF survival. Whereas C. jejuni can be considered a heat sensitive organism (δ value at 55 °C and buffer of pH 7.0 of 2 min, z value 4.40 °C), it showed a relatively high resistance to PEF as compared to other vegetative cells (δ value at 25 kV/cm and buffer of pH 7.0 of 7 pulses, zPEF value 8.20 kV/cm). Results obtained in this investigation indicate that Campylobacter spp. should be taken into account for the design of PEF treatments for food hygienization. Industrial relevance Before PEF can be commercially implemented it is necessary to determine its efficacy on pathogenic microorganisms of interest in order to ensure safety of food. There is no data available about the resistance of C. jejuni to pulsed electric fields, although it is now recognised as the leading cause of bacterial food-borne gastroenteritis throughout the world. In this research we characterize the resistance to heat and to PEF of C. jejuni NCTC 11351. Physiological factors affecting its survival to both agents are also explored.

Intracellular pH as an indicator of viability and resuscitation of Campylobacter jejuni after decontamination with lactic acid

The aim of the study was to determine intracellular pH (pH i) as an indicator of the physiological state of two Campylobacter jejuni strains (603 and 608) at the single cell level after bactericidal treatment with lactic acid (3% v/v lactic acid, pH 4.0, 0.85% w/v NaCl) and during recovery and survival using Fluorescence Ratio Imaging Microscopy (FRIM). After exposure to lactic acid solution a decline in pH i to 5.5 (FRIM detection limit) was observed in the majority of cells (75–100%) within 2 min. The enumeration data revealed that after 2 min of lactic acid exposure, approx. 90% of the initial population became unculturable. In the following 10 min of exposure, a further decrease in the cell count was observed resulting in 3.53 and 3.21 log CFU/ml reduction of culturable cells at the end of the treatment. On the contrary, the FRIM results revealed that the subpopulations with pH i > 5.5 increased between 2 and 12 min of exposure to lactic acid. Removing the acid stress and incubating the cells suspension under the more favourable conditions resulted in an immediate increase in cell population with pH i > pH ex for both C. jejuni strains. Further 24 h incubation at 37 °C resulted in increased pH i and colony count (recovery study). On the contrary, 24 h incubation at suboptimal temperature of 4 °C, showed pH i decrease to pH ex = 6.0 (no pH gradient) in the whole population of C. jejuni cells. Rather than dying, cells exposed for longer time (72 and 120 h) to 4 °C increased the subpopulation of the cells with positive pH gradient, mostly comprised of the cells with ΔpH > 0.5, indicating the ability of C. jejuni cells to regulate their metabolic activity under suboptimal conditions.

Enhanced enrichment and detection of thermotolerant Campylobacter species from water using the Portable Microbe Enrichment Unit and real-time PCR

An enhanced enrichment using the Portable Microbe Enrichment Unit (PMEU) with the microaerobic bubbling of broths was applied for the detection of thermotolerant Campylobacter species from water. This PMEU enrichment was compared with the conventional static enrichment of the international standard ISO 17995:2005. In addition, Campylobacter detection after enrichment using a real-time PCR detection was compared with colony counts. The tests with stressed Campylobacter jejuni cells in drinking water indicated that the PMEU enrichment yielded a significantly higher number of Campylobacter cells in the Bolton broth compared with the conventional static incubation. Application of the real-time PCR technique shortened the Campylobacter detection time. This combination of method modifications can be used for Campylobacter detection from water and adds methodological repertoire for the rapid survey and management of waterborne outbreaks.

Stress response and pathogenic potential of Campylobacter jejuni cells exposed to starvation

Campylobacter jejuni is a Gram-negative, fragile, spiral bacterium, known worldwide to be a major cause of acute human enteritis. Like many other food-borne bacteria, campylobacters must be able to survive under diverse conditions both inside the host and in the environment. Understanding stress response mechanisms provides information necessary for improving food processing and strategies that enhance food safety as well as clarifying the pathogenesis of campylobacteriosis. We investigated the relation between stress response to starvation and pathogenic potential in C. jejuni. Starvation changed the morphology and physiology of C. jejuni cells. However, the lower metabolic activity of 5-h-starved culture was not a dormant state, but probably a viable but non-culturable (VBNC) form of the cells, since starved C. jejuni induced heat stress resistance. The health hazard potential of starved cells is still unclear. We showed that, in spite of starvation, C. jejuni survived in vitro within Caco-2 enterocites up to 4 days and caused systemic campylobacteriosis in vivo in a mouse model. However, bacterial numbers in investigated organs were significantly lower and the infection was resolved sooner. Our results show that nutrient insufficiency is responsible for C. jejuni transformation, influencing but not abolishing its survival and virulence properties while in the VBNC state.

Production and characterization of a monoclonal antibody to Campylobacter jejuni.

Campylobacter species are a group of spiral-shaped bacteria that can cause disease in humans and animals. We developed a high-affinity monoclonal antibody (MAb) probe that recognizes Campylobacter jejuni cells. Cell suspensions grown under microaerobic conditions at 42 degrees C for 20 h on Bolton agar plates with lysed horse blood were used as live and heat-killed preparations, centrifuged at 8,000 x g for 20 min, and resuspended in carbonate buffer (pH 9.6) for coating on the enzyme-linked immunosorbent assay plates. BALB/c mice were immunized with C. jejuni sonicated cells at 10(7) CFU/ml to generate MAb-producing hybridoma clones. Of about 500 initial hybridoma clones, MAb 33D2, which reacted with C. jejuni and Campylobacter coli, was selected for further evaluation. MAb 33D2 is in the immunoglobulin subclass G2a and had relatively weaker reactivity with the C. coli strains tested. MAb 33D2 did not show any cross-reactions with the nine non-Campylobacter bacteria tested in the enzyme-linked immunosorbent assay and had a stronger affinity for C. jejuni as live versus heat-killed cells. In Western blot assays, MAb 33D2 recognized two major antigens of 62 and 43 kDa in extracts from C. jejuni cells but only one antigen of 62 kDa in extracts from C. coli cells.

Campylobacter and Arcobacter species sensitivity to commercial orange oil fractions

Seven orange oil fractions were screened for their ability to inhibit the growth of selected Campylobacter and Arcobacter spp. using the standard agar-disk diffusion assay. Cold pressed (CP) terpeneless Valencia orange oil was found to be the most inhibitory to both Campylobacter jejuni and Campylobacter coli, exhibiting maximum zones of inhibition up to 80 ± 0.0 mm. Five-fold concentrated Valencia oil and distilled d-limonene resulted in Campylobacter inhibition zones ranging from 11.0 ± 1.4 to 44 ± 1.4 mm against both C. jejuni and C. coli. No inhibition of Arcobacter spp. was detected by 6 out of 7 orange fractions except CP terpeneless Valencia orange oil which produced inhibition zones varying from 9.5 ± 0.7 to 29 ± 1.4 mm. Naturally occurring C. jejuni UAF 244 was isolated from a whole retail chicken, confirmed by hippuricase gene PCR assay, and used to determine antimicrobial capacities of the CP terpeneless Valencia orange oil and limonene when applied on chicken legs and thighs. The two types of chicken parts did not influence the antimicrobial strength of both orange fractions. While the observed reduction of C. jejuni cells attached to the skin varied approximately 1.5 to 2 logarithms compared to the control, the growth inhibition of the bacterial cells by limonene in the rinse increased by 6-fold and complete inhibition without recovery of detectable viable cells occurred when CP Valencia orange oil was applied. The study demonstrated the potential of the selected commercial orange oil fractions to serve as natural antimicrobials against C. jejuni, C. coli, and Arcobacter spp.

Survival of Campylobacter jejuni in mineral bottled water according to difference in mineral content: Application of the Weibull model

The aim of the study was to examine the hypothesis proposed by Evans et al. [2003. Hazards of healthy living: bottled water and salad vegetables as risk factors for Campylobacter infection. Emerg. Infect. Dis. 9(10), 1219–1225] that mineral bottled water accidentally contaminated by Campylobacter jejuni would represent a risk factor for C ampylobacter infection. Culturability of C. jejuni cells inoculated in low- and high-mineral bottled water during storage at 4 °C in the dark was performed by surface plating and modelled using the Weibull model. The loss of C. jejuni culturability observed in all conditions tested was shown to be dependent on strain, preculture condition and water composition. Following inoculation of C. jejuni, the rapid loss of culturability was not correlated to complete cell death as the passage into embryonated eggs enabled recovery of cells from the viable but non-culturable state. In conclusion, the sanitary risk associated with contaminated bottled water cannot be excluded although it is presumably low. Culture conditions, strain and water type must be taken into account in the evaluation of the risk factors as they influence significantly Campylobacter survival in water.

Commonality and Biosynthesis of the O-Methyl Phosphoramidate Capsule Modification in Campylobacter jejuni

In this study we investigated the commonality and biosynthesis of the O-methyl phosphoramidate (MeOPN) group found on the capsular polysaccharide (CPS) of Campylobacter jejuni. High resolution magic angle spinning NMR spectroscopy was used as a rapid, high throughput means to examine multiple isolates, analyze the cecal contents of colonized chickens, and screen a library of CPS mutants for the presence of MeOPN. Sixty eight percent of C. jejuni strains were found to express the MeOPN with a high prevalence among isolates from enteritis, Guillain Barré, and Miller-Fisher syndrome patients. In contrast, MeOPN was not observed for any of the Campylobacter coli strains examined. The MeOPN was detected on C. jejuni retrieved from cecal contents of colonized chickens demonstrating that the modification is expressed by bacteria inhabiting the avian gastrointestinal tract. In C. jejuni 11168H, the cj1415-cj1418 cluster was shown to be involved in the biosynthesis of MeOPN. Genetic complementation studies and NMR/mass spectrometric analyses of CPS from this strain also revealed that cj1421 and cj1422 encode MeOPN transferases. Cj1421 adds the MeOPN to C-3 of the beta-d-GalfNAc residue, whereas Cj1422 transfers the MeOPN to C-4 of D-glycero-alpha-L-gluco-heptopyranose. CPS produced by the 11168H strain was found to be extensively modified with variable MeOPN, methyl, ethanolamine, and N-glycerol groups. These findings establish the importance of the MeOPN as a diagnostic marker and therapeutic target for C. jejuni and set the groundwork for future studies aimed at the detailed elucidation of the MeOPN biosynthetic pathway.

IN VITRO SURVIVAL AT LOW pH AND ACID ADAPTATION RESPONSE OF CAMPYLOBACTER JEJUNI AND CAMPYLOBACTER COLI

ABSTRACT The survival of Campylobacter jejuni and Campylobacter coli at pH 7.0, 6.0, 5.0 and 4.0 for up to 24 h, and the induction of an acid adaptation response in 12 C. jejuni and 10 C. coli strains in early exponential or late stationary phases in tryptic soy broth (TSB) and Brucella broth were investigated. C. coli strains were more sensitive than C. jejuni in media adjusted to pH 5.0 or 4.0 with hydrochloric acid. Five log10 cfu/mL of C. coli were inhibited at 12 h in pH 5.0, but only 2.5 log10 cfu/mL of C. jejuni cells were inhibited under the same conditions. No viable cells were detected at 4 h in pH 4.0 from an inoculum of 6 log10 cfu/mL of C. coli. Late stationary phase cells of C. jejuni exposed to pH 5.0 for 4 h in TSB exhibited a significant (P ≤ 0.05) acid tolerance response when compared to nonexposed cells. Late stationary phase cells of C. coli exposed to pH 5.0 for 3 h in TSB and late stationary and early exponential phase cells exposed to pH 5.0 for 3 h in Brucella broth showed a significant (P ≤ 0.05) acid tolerance response when compared to nonexposed cells. The acid tolerance responses observed for C. jejuni and C. coli conferred adapted cells no more than 1 log10 cfu/mL survival advantage over nonadapted cells. Brucella broth appeared to be more protective than TSB for the survival of C. jejuni and C. coli at pH 4.0.

A major role for intestinal epithelial nucleotide oligomerization domain 1 (NOD1) in eliciting host bactericidal immune responses to Campylobacter jejuni

Campylobacter jejuni is the foremost cause of bacterial-induced diarrhoeal disease worldwide. Although it is well established that C. jejuni infection of intestinal epithelia triggers host innate immune responses, the mechanism(s) involved remain poorly defined. Innate immunity can be initiated by families of structurally related pattern-recognition receptors (PRRs) that recognize specific microbial signature motifs. Here, we demonstrated maximal induction of epithelial innate responses during infection with live C. jejuni cells. In contrast when intestinal epithelial cells (IECs) were exposed to paraformaldehyde-fixed bacteria, host responses were minimal and a marked reduction in the number of intracellular bacteria was noted in parallel. These findings suggested a role for intracellular host-C. jejuni interactions in eliciting early innate immunity. We therefore investigated the potential involvement of a family of intracellular, cytoplasmic PRRs, the nucleotide-binding oligomerization domain (NOD) proteins in C. jejuni recognition. We identified NOD1, but not NOD2, as a major PRR for C. jejuni in IEC. We also found that targeting intestinal epithelial NOD1 with small interfering RNA resulted in an increase in number of intracellular C. jejuni, thus highlighting a critical role for NOD1-mediated antimicrobial defence mechanism(s) in combating this infection at the gastrointestinal mucosal surface.

Media for the Aerobic Resuscitation of Campylobacter jejuni

The microaerophilic nature of Campylobacter jejuni has complicated its recovery from human and animal sources. In this study, enhancement of the growth and aerotolerance of C. jejuni ATCC 35921 in nutrient broth no. 2 (NB2) was investigated. The efficiency of recovery of C. jejuni in NB2 containing FBP (0.025% [each] ferrous sulfate, sodium metabisulfite, and sodium pyruvate), 5% laked horse blood, hemin, Oxyrase, or activated charcoal in an aerobic atmosphere was compared with that obtained under microaerophilic incubation. The shortest lag time (λ) for cells grown aerobically was observed with NB2 supplemented with FBP, 5% laked horse blood, 0.01 g/liter of hemin, or 0.15 U/ml of Oxyrase. The efficacy of these media to resuscitate C. jejuni cells in late exponential phase, as well as cells subjected to stress induced by cold, heat, starvation, or acid, was determined in aerobic or microaerobic atmospheres. The λ of cells grown aerobically in NB2 containing both FBP and blood was similar to that obtained in the same medium incubated in a microaerobic environment (P > 0.05). However, the λ was longer during aerobic growth when low numbers of cells (approximately 1 log CFU/ml) in late exponential phase were used as the initial inoculum. The best recovery of stressed C. jejuni was observed in NB2 supplemented with FBP and blood and incubated aerobically. Enrichment in media incorporating FBP and 5% laked horse blood is a simple, convenient, and time-saving method to replace microaerophilic incubation methods for the resuscitation of C. jejuni.

Comparison of Escherichia coli and Campylobacter jejuni Transport in Saturated Porous Media

Due to the difficulties in testing for specific pathogens, water samples are tested for the presence of nonpathogenic indicator organisms to determine whether a water supply has been contaminated by fecal material. An implicit assumption in this approach is that where pathogenic microorganisms are present fecal indicator organisms are present as well; yet surprisingly few studies have been conducted that directly compare the transport of indicator organisms with pathogenic organisms in ground water environments. In this study we compared the cell properties and transport of Escherichia coli, a commonly used indicator organism, and Campylobacter jejuni, an important enteropathogen commonly found in agricultural wastes, through saturated porous media. Differences in cell properties were determined by measuring cell geometry, hydrophobicity, and electrophoretic mobility. Transport differences were determined by conducting miscible displacement experiments in laboratory columns. Under the experimental conditions tested, C. jejuni was much more negatively charged and more hydrophobic than E. coli. In addition, C. jejuni cells were slightly longer, narrower, and less spherical than E. coli. The variations in cell properties, primarily surface charge, resulted in significant differences in transport between these two microorganisms, with the transport of C. jejuni exceeding that of E. coli when conditions favored low attachment rates, thus calling into question the usefulness of using E. coli as an indicator organism for this important pathogen.

Expression and purification of native and truncated forms of CadF, an outer membrane protein of Campylobacter

Campylobacter is now recognized as the most common bacterial agent of gastroenteritis. The adhesion of bacteria to intestinal cells is a major step in human colonization. The binding of Campylobacter jejuni cells to fibronectin (Fn), a component of the extra cellular matrix, is mediated by a 37,000 outer membrane protein termed CadF for Campylobacter adhesion to Fn. CadF protein is very hard to purify from Campylobacter membranes. In order to study the conformation of this protein, we set out to clone, express, purify, and re-fold the CadF protein. The nucleotide sequence encoding the N-terminal domain of the CadF protein was cloned in a pET-based expression vector. The recombinant protein was further produced in Escherichia coli, purified from inclusion bodies, and refolded. More specifically, the purification experiments were set-up as follows: (i) protein aggregates were collected from cell-lysates, solubilized in urea and enriched by ion-exchange chromatography; (ii) refolding was achieved by drop-by-drop dilution method in detergent containing buffer and monitored by CD measurements; (iii) the protein was finally purified to homogeneity by gel filtration chromatography. In spite of our success in purifying the N-terminal domain of the CadF protein, repeated attempts to express and purify the entire cadF gene in E. coli failed. Using a novel approach, we found it possible to express the entire cadF gene fused to a hexa-histidine encoding nucleotide sequence in C. jejuni. This allowed the expression, synthesis, and purification of the recombinant CadF-His tagged protein from C. jejuni by nickel affinity chromatography followed by gel filtration chromatography. In summary, we developed a novel strategy to produce significant quantities of a recombinant N-terminal portion of the CadF protein (46.5 μg/mg of bacterial dry weight) and of the native CadF protein (3.5 μg/mg of bacterial dry weight) for further studies.

Development of a real-time NASBA assay for the detection of Campylobacter jejuni cells

The objectives of this study were the development of a real-time NASBA assay for the detection of Campylobacter jejuni mRNA and the evaluation of its potential to determine the viability of the detected C. jejuni cells. A set of specific primers and probes was chosen to amplify the mRNA of the tuf-gene and the GTPase-gene. Only the tuf-assay was able to detect as low as 10 2 cells per NASBA reaction and was specific for Campylobacter. However, as the assay was able to detect dead cells, it cannot be used to demonstrate the viability of C. jejuni cells . The tuf-gene mRNA is no good viability indicator due to its stability.

The ability of flagellum-specific Proteus vulgaris bacteriophage PV22 to interact with Campylobacter jejuni flagella in culture

BackgroundThere has been a recent resurgent interest in bacteriophage biology. Research was initiated to examine Campylobacter jejuni-specific bacteriophage in the Russian Federation to develop alternative control measures for this pathogen.ResultsA C. jejuni flagellum-specific phage PV22 from Proteus vulgaris was identified in sewage drainage. This phage interacted with C. jejuni by attachment to flagella followed by translocation of the phage to the polar region of the bacterium up to the point of DNA injection. Electron microscopic examination revealed adsorption of PV22 on C. jejuni flagella after a five minute incubation of the phage and bacteria. A different phenomenon was observed after incubating the mix under the same conditions, but for twenty minutes or longer. Phage accumulated primarily on the surface of cells at sites where flagella originated. Interestingly, PV22 did not inject DNA into C. jejuni and PV22 did not produce lytic plaques on medium containing C. jejuni cells. The constant of velocity for PV22 adsorption on cells was 7 × 10-9 ml/min.ConclusionIt was demonstrated that a bacteriophage that productively infects P. vulgaris was able to bind C. jejuni and by a spot test that the growth of C. jejuni was reduced relative to control bacteria in the region of phage application. There may be two interesting applications of this effect. First, it may be possible to test phage PV22 as an antimicrobial agent to decrease C. jejuni colonization of the chicken intestine. Second, the phage could potentially be utilized for investigating biogenesis of C. jejuni flagella.