Substrate utilization by Campylobacter jejuni and Campylobacter coli.

An attempt was made to elucidate in Campylobacter spp. some of the physiologic characteristics that are reflected in the kinetics of CO2 formation from four 14C-labeled substrates. Campylobacter jejuni and C. coli were grown in a biphasic medium, and highly motile spiral cells were harvested at 12 h. Of the media evaluated for use in the metabolic tests, minimal essential medium without glutamine, diluted with an equal volume of potassium sodium phosphate buffer (pH 7.2), provided the greatest stability and least competition with the substrates to be tested. The cells were incubated with 0.02 M glutamate, glutamine, alpha-ketoglutarate, or formate, or with concentrations of these substrates ranging from 0.0032 to 0.125 M. All four substrates were metabolized very rapidly by both species. A feature of many of these reactions, particularly obvious with alpha-ketoglutarate, was an immediate burst of CO2 production followed by CO2 evolution at a more moderate rate. These diphasic kinetics of substrate utilization were not seen in comparable experiments with Escherichia coli grown and tested under identical conditions. With C. jejuni, CO2 production from formate proceeded rapidly for the entire period of incubation. The rate of metabolism of glutamate, glutamine, and alpha-ketoglutarate by both species was greatly enhanced by increased substrate concentration. The approach to the study of the metabolism of campylobacters here described may be useful in detecting subtle changes in the physiology of cells as they are maintained past their logarithmic growth phase.     

Serological diagnosis of Campylobacter jejuni infections

Antibody level to Campylobacter in 28 sera of patients of whom Campylobacter infection was confirmed by germ isolation from feces was tested. The investigation was performed using passive haemagglutination technique and as antigens heated and acid glycine extraction prepared from homologous and reference strains. For the method used the heated antigen proved to be superior. Out of 28 tested patients of whom 92.8% were children, 8 sera were positive, 9 doubtful and 9, derived mainly from neonates (0-14 month of age), were negative.     

Laboratory infection of chicken eggs with Campylobacter jejuni by using temperature or pressure differentials.

Fertile chicken eggs were infected in our laboratory with Campylobacter jejuni suspensions by using temperature or pressure differential methods of inoculation. After 2 days of incubation, over 90% of the eggs carried C. jejuni when iron was present in the inoculum. This percentage declined rapidly until by day 8, less than 10% of the eggs were detectably infected. However, up to 11% of hatched, healthy chicks carried C. jejuni in their intestinal tracts. The isolated organisms were of the same serotype as the initial inoculum. C. jejuni was recovered without difficulty when the intestinal tracts of chicks were enriched, but recovery from early dead-in-shell or infertile eggs was poor. This poor recovery and the rapid decline of C. jejuni after 2 days of egg incubation suggest that the vibrio is sensitive to some part of the incubating egg or to the temperature of prolonged incubation. It was impossible to predict which eggs would yield infected chicks on the basis of the number of organisms taken up by each egg, and no correlation existed between the number of organisms taken up and the efficiency of the hatch, i.e., the hatch ratio. If iron was omitted from the inoculum broth, the egg infection rate at day 2 was lower.     

Campylobacter jejuni infection associated with relatively poor condition and low survival in a wild bird

Campylobacter jejuni is the most common foodborne pathogen in industrialized countries. Most human infections come from contaminated poultry, but wild birds are also known to harbor C. jejuni. Wild birds are often described as asymptomatic carriers, but this assumption is based on domestic poultry research. We studied the effects of C. jejuni infection on body condition and survival of adult and nestling American crows Corvus brachyrhynchos in Davis, California. Previous work demonstrated that more than half of the crows in this population are infected with C. jejuni and that at least some of the isolates carried by crows are similar to those found in domestic animals and humans. In this study, we compared the body condition of infected and uninfected individuals at the time of capture among adults (n = 44; 52% infected) and nestlings (n = 97; 77% infected). We subsequently monitored these banded individuals for up to 3 yr and used mark–recapture survival analysis to estimate relationships between infection status and later survival. We found that adult crows infected with C. jejuni were in poor condition relative to uninfected adults: average body mass of infected birds was 12% lower, whereas average body size did not differ between the two groups. Likewise, apparent survival probability was lower for infected adults. In contrast, nestling body condition, fledging success, and survival did not differ by infection status. This is the first study to document adverse effects of C. jejuni infection in a free‐living, wild bird. If these effects are widespread, C. jejuni exposure may be a cause of conservation concern for some species, especially when human activities increase exposure to infections or introduce novel strains to wild bird populations. Our results add to the growing body of work demonstrating hidden long‐term costs of seemingly mild infections in wild populations.     

Minicell formation by Campylobacter jejuni

Campylobacter jejuni sheds its flagella and varying proportions of the poles of the cell late in the growth cycle, resulting in the production of very small flagellated structures 0.1 to 0.3 microM in diameter. Electron microscopy revealed that these structures were minicells possessing outer membrane, cytoplasmic membrane, flagellar basal complex, and polar membrane; nucleoplasms were not seen. The initial event in the formation of these minicells involved a constriction of the cytoplasmic membrane, segregating the polar regions of the cell. The peptidoglycan layer of the cell wall was not visible, but was presumed to lyse at the separation site of minicell formation, and to reform or remain intact along the main length of the cell because the rods did not spheroplast. Finally, rupture and resealing of the outer membrane component of the wall resulted in the release of fully enclosed minicells and nonflagellated rods.     

空肠弯曲菌感染动物模型的研究进展

空肠弯曲菌是一种全球关注的人兽共患病原菌,感染后可引起人和动物多种疾病。动物模型是开展致病机理、疫苗评价和药物开发等研究的基础。空肠弯曲菌由于培养条件苛刻以及感染实验动物的疾病相似性、经济性和重复性等因素,仍缺乏良好的感染动物模型,其致病机理迄今尚不清楚。本文对已报道的空肠弯曲菌感染实验动物模型进行综述。     

Polymicrobial infection in Campylobacter jejuni enteritis in Karachi

Between September 1984 and April 1985, 210 stool specimens from patients with acute enteritis, in the city of Karachi, Pakistan were cultured for the presence of different enteropathogenic bacterial agents.Campylobacter jejuni was isolated from 62 (29.5%) of these specimens from children under 2 years of age. The highest incidence of C. jejuni was found among infants from birth to 6 months of age. The frequency of isolation gradually decreased among the 7–12-month-old infants and again among children from 13–24 months of age, respectively. C. jejuni was more frequently isolated in stool specimens from males (61.2%) and reflected the higher incidence of illness caused by C. jejuni in males. Our results emphasise the importance of this newly recognised enteropathogen, C. jejuni, in the etiology of diarrhoeal disease in Pakistan.     

Protection against Campylobacter jejuni infection in suckling mice by anti-flagellar antibody

We obtained two monoclonal antibodies of IgM class and IgA class of immunoglobulin prepared from mouse spleen cells immunized with crude flagellar preparation, and a polyclonal antibody raised against purified flagellin monomer of Campylobacter jejuni in a rabbit. The specificity of the reaction of these antibodies for flagellar filament was confirmed by Western blotting and by immunoelectron microscopy. These antibodies caused agglutination of the bacteria and inhibited the motility of the bacteria. When a strain of C. jejuni was treated with IgM class monoclonal antibody before being inoculated into suckling mice, it reduced colonization of the intestinal tract by this bacteria. Inhibition of the colonization by IgA class monoclonal antibody was less effective than that of IgM class, and the polyclonal antibody consisting mostly of IgG class immunoglobulin was without effect.     

Substrate utilization by Campylobacter jejuni and Campylobacter coli

An attempt was made to elucidate in Campylobacter spp. some of the physiologic characteristics that are reflected in the kinetics of CO2 formation from four 14C-labeled substrates. Campylobacter jejuni and C. coli were grown in a biphasic medium, and highly motile spiral cells were harvested at 12 h. Of the media evaluated for use in the metabolic tests, minimal essential medium without glutamine, diluted with an equal volume of potassium sodium phosphate buffer (pH 7.2), provided the greatest stability and least competition with the substrates to be tested. The cells were incubated with 0.02 M glutamate, glutamine, alpha-ketoglutarate, or formate, or with concentrations of these substrates ranging from 0.0032 to 0.125 M. All four substrates were metabolized very rapidly by both species. A feature of many of these reactions, particularly obvious with alpha-ketoglutarate, was an immediate burst of CO2 production followed by CO2 evolution at a more moderate rate. These diphasic kinetics of substrate utilization were not seen in comparable experiments with Escherichia coli grown and tested under identical conditions. With C. jejuni, CO2 production from formate proceeded rapidly for the entire period of incubation. The rate of metabolism of glutamate, glutamine, and alpha-ketoglutarate by both species was greatly enhanced by increased substrate concentration. The approach to the study of the metabolism of campylobacters here described may be useful in detecting subtle changes in the physiology of cells as they are maintained past their logarithmic growth phase.     

Laboratory infection of chicken eggs with Campylobacter jejuni by using temperature or pressure differentials

Fertile chicken eggs were infected in our laboratory with Campylobacter jejuni suspensions by using temperature or pressure differential methods of inoculation. After 2 days of incubation, over 90% of the eggs carried C. jejuni when iron was present in the inoculum. This percentage declined rapidly until by day 8, less than 10% of the eggs were detectably infected. However, up to 11% of hatched, healthy chicks carried C. jejuni in their intestinal tracts. The isolated organisms were of the same serotype as the initial inoculum. C. jejuni was recovered without difficulty when the intestinal tracts of chicks were enriched, but recovery from early dead-in-shell or infertile eggs was poor. This poor recovery and the rapid decline of C. jejuni after 2 days of egg incubation suggest that the vibrio is sensitive to some part of the incubating egg or to the temperature of prolonged incubation. It was impossible to predict which eggs would yield infected chicks on the basis of the number of organisms taken up by each egg, and no correlation existed between the number of organisms taken up and the efficiency of the hatch, i.e., the hatch ratio. If iron was omitted from the inoculum broth, the egg infection rate at day 2 was lower.     

Phase-variable surface structures are required for infection of Campylobacter jejuni by bacteriophages

This study characterizes the interaction between Campylobacter jejuni and the 16 phages used in the United Kingdom typing scheme by screening spontaneous mutants of the phage-type strains and transposon mutants of the sequenced strain NCTC 11168. We show that the 16 typing phages fall into four groups based on their patterns of activity against spontaneous mutants. Screens of transposon and defined mutants indicate that the phage-bacterium interaction for one of these groups appears to involve the capsular polysaccharide (CPS), while two of the other three groups consist of flagellatropic phages. The expression of CPS and flagella is potentially phase variable in C. jejuni, and the implications of these findings for typing and intervention strategies are discussed.     

Campylobacter jejuni infection within a laboratory animal production unit

A conventional laboratory animal production unit in which rats, mice, guineapigs and rabbits were bred in one building and cats maintained in a separate, but adjacent area was examined for the presence of intestinal thermophilic Campylobacter spp. Campylobacter jejuni was recovered from 18.84% of 552 animals. The infection rate was highest amongst the cats (51.7%), with rats being the second most commonly infected (23.2%), whereas only 7.7% of guineapigs and a single rabbit (1%) were positive. Campylobacter-like organisms were cultured from 10% of the mice, but these bacteria failed to grow on subsequent subculturing. By using bacterial restriction endonuclease DNA analysis (BRENDA), a single type of C. jejuni was identified from all isolates recovered from the rats, guineapigs and a rabbit, suggesting a common source of infection. In contrast, there were 5 different BRENDA patterns derived from cat isolates. No isolates of C. jejuni were obtained from humans working within the unit or from animal bedding or the immediate environment, although it was suggested that the organism may have entered and spread within the unit from sawdust.     

Inactivation of Campylobacter jejuni by chlorine and monochloramine.

Campylobacter jejuni and closely related organisms are important bacterial causes of acute diarrheal illness in the United States. Both endemic and epidemic infections have been associated with consuming untreated or improperly treated surface water. We compared susceptibility of three C. jejuni strains and Escherichia coli ATCC 11229 with standard procedures used to disinfect water. Inactivation of bacterial preparations with 0.1 mg of chlorine and 1.0 mg of monochloramine per liter was determined at pH 6 and 8 and at 4 and 25 degrees C. Under virtually every condition tested, each of the three C. jejuni strains was more susceptible than the E. coli control strain, with greater than 99% inactivation after 15 min of contact with 1.0 mg of monochloramine per liter or 5 min of contact with 0.1 mg of free chlorine per liter. Results of experiments in which an antibiotic-containing medium was used suggest that a high proportion of the remaining cells were injured. An animal-passaged C. jejuni strain was as susceptible to chlorine disinfection as were laboratory-passaged strains. These results suggest that disinfection procedures commonly used for treatment of drinking water to remove coliform bacteria are adequate to eliminate C. jejuni and further correlate with the absence of outbreaks associated with properly treated water.     

Genome maps of Campylobacter jejuni and Campylobacter coli.

Little information concerning the genome of either Campylobacter jejuni or Campylobacter coli is available. Therefore, we constructed genomic maps of C. jejuni UA580 and C. coli UA417 by using pulsed-field gel electrophoresis. The genome sizes of C. jejuni and C. coli strains are approximately 1.7 Mb, as determined by SalI and SmaI digestion (N. Chang and D. E. Taylor, J. Bacteriol. 172:5211-5217, 1990). The genomes of both species are represented by single circular DNA molecules, and maps were constructed by partial restriction digestion and hybridization of DNA fragments extracted from low-melting-point agarose gels. Homologous DNA probes, encoding the flaAB and 16S rRNA genes, as well as heterologous DNA probes from Escherichia coli, Bacillus subtilis, and Haemophilus influenzae, were used to identify the locations of particular genes. C. jejuni and C. coli contain three copies of the 16S and 23S rRNA genes. However, they are not located together within an operon but show a distinct split in at least two of their three copies. The positions of various housekeeping genes in both C. jejuni UA580 and C. coli UA417 have been determined, and there appears to be some conservation of gene arrangement between the two species.     

Colonization of broiler chickens by waterborne Campylobacter jejuni.

Chickens on a broiler farm in southern England were found to be colonized with Campylobacter jejuni of a single serotype, Lior 1 Penner 4. The farm was the sole supplier of a local slaughterhouse associated with a campylobacter outbreak in 1984 caused by this serotype. The serotype persisted on the farm for at least 18 months after the outbreak; its prevalence in the human population served by the farm remained high until it disappeared from the farm in 1986. The possible sources and routes of transmission of C. jejuni to the broilers on the farm were investigated. The results showed that vertical transmission, feed, litter, small mammals, and environmental or airborne cross-contamination between sheds or successive crops could be excluded as persistent sources of C. jejuni. The predominant source of C. jejuni on the farm was shown to be the water supply. Direct microscopy and fluorescent antibody methods revealed presumptive campylobacters throughout the farm's water system. Campylobacter-free chickens raised in an animal house and given water from the farm supply became colonized with the serotype of C. jejuni endemic on the farm (Lior 1 Penner 4). An intervention program based on water chlorination, shed drinking system cleaning and disinfection, and withdrawal of furazolidone from feed reduced the proportion of birds colonized with campylobacter from 81 to 7% and was associated with a 1,000- to 10,000-fold reduction in campylobacters recoverable from the carcasses. Two months after the end of the intervention program colonization of the birds returned to high levels (84%), indicating that there was a temporal association between intervention and reduced colonization with C. jejuni. Investigations continue to establish the general applicability of these findings.