Identification and molecular epidemiology of Campylobacter coli isolates from human gastroenteritis, food, and animal sources by amplified fragment length polymorphism analysis and Penner serotyping

Circulation of thermophilic Campylobacter in pigeons, turkeys, and humans at live bird markets in Egypt

Live bird markets increase the risk of transmission of zoonotic diseases. Few studies have investigated the potential zoonotic transmission of Campylobacter in Egypt. Therefore, our study was carried out to investigate the presence of Campylobacter species, mainly Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli), in pigeons and turkeys sold at poultry shops. Furthermore, the study aimed to explore the potential occupational risk of Campylobacter infection, mainly among workers at poultry shops. Six hundred (n = 600) samples from various organs were obtained from pigeons and turkeys from live bird shops in the Giza and Asyut provinces in Egypt. Additionally, 100 stool samples were collected from persons working at poultry shops. Circulation of thermophilic Campylobacter in pigeons, turkeys, and humans was investigated based on culture and molecular methods. The rate of detection of Campylobacter species from the samples was significant when the culture method was used alone in comparison to when it was used in combination with mPCR. The prevalence rates of Campylobacter species detected by mPCR were 36% (C. jejuni 20%; C. coli 16%), 28% (C. jejuni 12%; C. coli16%), and 29% (C. jejuni 15%; C. coli 14%) in pigeons, turkeys, and workers, respectively. In pigeons, significant variations in the C. jejuni and C. coli occurrence rates were reported in terms of the intestinal content (15, 4%), liver (4, 13%), and skin (9, 7%), respectively. In turkeys, Campylobacter species were mostly detected in liver samples with a percentage of 19%, followed by the skin (12%), and the intestinal content (8%). In conclusion, Campylobacter species are circulating in poultry farms in Egypt and could represent a hazard for humans. It is recommended that biosecurity measures should be applied to mitigate the occurrence of Campylobacter in poultry farms. Moreover, there is an urgent need to transform live bird markets into chilled poultry markets.

Pulsed-field gel electrophoresis fingerprinting of Campylobacter jejuni and Campylobacter coli strains isolated from clinical specimens, Iran

The aim of this study was to determine the clonal correlation of Campylobacter strains isolated from diarrheal children under 5 years of age in Iran using the PFGE method and to determine the antimicrobial susceptibility and virulence gene content of strains. Of 750 patients with bacterial diarrhea, 33 (4%) Campylobacter spp., including 31 C. jejuni (94%) and 2 C. coli (6%), were isolated during 18-month period in Tehran, Iran. Except for one strain, remaining Campylobacter strains were positive for the flaA gene. A complete set of cytolethal distending toxin (CDT) encoding genes (cdtABC) were detected in 52% of the C. jejuni strains, while the 2 C. coli isolates under study only harbored cdtA and cdtB of the CDT cluster. All strains were resistant to at least three antibiotic classes. Resistance to ampicillin among C. coli and C. jejuni strains was 100% and 84%, respectively, and 80% of all strains were susceptible to gentamicin. PFGE genotyping generated 19 pulsotypes with two major clusters, displaying the maximum and minimum similarity of 100% and 26%, respectively. The C. coli strains showed clearly distinct pulsotypes and each fell within separate clusters. A very homogeneous Campylobacter population was detected among Iranian patients with 33 % of strains showing identical banding patterns and no clear correlation was observed between antibiotic resistance profiles and PFGE patterns of the isolates.

Advanced molecular diagnostic techniques for detection of food-borne pathogens: Current applications and future challenges

The elimination of disease-causing microbes from the food supply is a primary goal and this review deals with the overall techniques available for detection of food-borne pathogens. Now-a-days conventional methods are replaced by advanced methods like Biosensors, Nucleic Acid-based Tests (NAT), and different PCR-based techniques used in molecular biology to identify specific pathogens. Bacillus cereus, Staphylococcus aureus, Proteus vulgaris, Escherichia coli, Campylobacter, Listeria monocytogenes, Salmonella spp., Aspergillus spp., Fusarium spp., Penicillium spp., and pathogens are detected in contaminated food items that cause always diseases in human in any one or the other way. Identification of food-borne pathogens in a short period of time is still a challenge to the scientific field in general and food technology in particular. The low level of food contamination by major pathogens requires specific sensitive detection platforms and the present area of hot research looking forward to new nanomolecular techniques for nanomaterials, make them suitable for the development of assays with high sensitivity, response time, and portability. With the sound of these, we attempt to highlight a comprehensive overview about food-borne pathogen detection by rapid, sensitive, accurate, and cost affordable in situ analytical methods from conventional methods to recent molecular approaches for advanced food and microbiology research.

Prevalence and antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolated from children and environmental sources in urban and suburban areas

BACKGROUND

Campylobacteriosis is a dominant bacterial cause of foodborne infection and is considered the main public health problem in Europe and many other countries worldwide. In the study lasting from 2011 to 2013 we compared the prevalence and antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolated from children, domestic animals, poultry meat and surface water in Northern Poland.

RESULTS

During a 3-years study 1973 samples were analysed. The results proved the presence of Campylobacter spp. in 306 (15.5%) samples. The percentage of Campylobacter-positive samples differed among the sample types, from 0% (freshwater beaches) to 38.6% (poultry meat in 2011). Prevalence of Campylobacter spp. in children isolates was 9.6%. It decreased from 13.2% in 2011 to 8.0% in 2013. It should be highlighted with a particular concern that Campylobacter jejuni was detected in 20.0% of fountains. All children and poultry meat isolates were susceptible to azithromycin. Two C. coli (3.7%) and four C. jejuni (3.3%) isolated from poultry meat were resistant to erythromycin. The highest percentage of C. jejuni isolates with resistance to ciprofloxacin were found in samples from 80% dogs and 85% ponds. Among isolates resistant to two antimicrobials 74.7% C. jejuni and 59.2% C. coli isolates were resistant to ciprofloxacin as well as to tetracycline. Only one cat C. coli isolate was resistant to both azithromycin and erythromycin. One C. jejuni isolate from a fountain was resistant to four antimicrobial agents (erythromycin, azithromycin, tetracycline and ciprofloxacin).

CONCLUSIONS

The study proved that surface water, poultry meat and pets constituted potential sources of Campylobacter to children. Fountains can be a direct source of children campylobacteriosis but can also pollute other environments with multidrug-resistant Campylobacter. The high resistance to some antimicrobials among the isolates may lead to increasing numbers of difficult-to-treat campylobacteriosis cases among children.

Faeco-prevalence of Campylobacter jejuni in urban wild birds and pets in New Zealand

Background

Greater attention has been given to Campylobacter jejuni (C. jejuni) prevalence in poultry and ruminants as they are regarded as the major contributing reservoirs of human campylobacteriosis. However, relatively little work has been done to assess the prevalence in urban wild birds and pets in New Zealand, a country with the highest campylobacteriosis notification rates. Therefore, the aim of the study was to assess the faeco-prevalence of C. jejuni in urban wild birds and pets and its temporal trend in the Manawatu region of New Zealand.

Findings

A repeated cross-sectional study was conducted from April 2008 to July 2009, where faecal samples were collected from 906 ducks, 835 starlings, 23 Canadian goose, 2 swans, 2 pied stilts, 498 dogs and 82 cats. The faeco-prevalence of C. jejuni was 20% in ducks, 18% in starlings, 9% in Canadian goose, 5% in dogs and 7% in cats. The faeco-prevalence of C. jejuni was relatively higher during warmer months of the year in ducks, starlings and dogs while starlings showed increased winter prevalence. No such trend could be assessed in Canadian goose, swans, pied stilts and cats as samples could not be collected for the entire study period from these species.

Conclusions

This study estimated the faeco-prevalence of C. jejuni in different animal species where the prevalence was relatively high during warmer months in general. However, there was relative increase in winter prevalence in starlings. The urban wild bird species and pets may be considered potential risk factors for human campylobacteriosis in New Zealand, particularly in small children.

Comparative population structure analysis of Campylobacter jejuni from human and poultry origin in Bangladesh

Campylobacter jejuni is the most important cause of antecedent infections leading to Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS). The objective of the present study was to define the genetic diversity, population structure, and potential role of poultry in the transmission of Campylobacter to humans in Bangladesh. We determined the population structure of C. jejuni isolated from poultry (n = 66) and patients with enteritis (n = 39) or GBS (n = 10). Lipooligosaccharide (LOS) typing showed that 50/66 (76 %) C. jejuni strains isolated from poultry could be assigned to one of five LOS locus classes (A-E). The distribution of neuropathy-associated LOS locus classes A, B, and C were 30/50 (60 %) among the typable strains isolated from poultry. The LOS locus classes A, B, and C were significantly associated with GBS and enteritis-related C. jejuni strains more than for the poultry strains [(31/38 (82 %) vs. 30/50 (60 %), p < 0.05]. Multilocus sequence typing (MLST) defined 15 sequence types (STs) and six clonal complexes (CCs) among poultry isolates, including one ST-3740 not previously documented. The most commonly identified type, ST-5 (13/66), in chicken was seen only once among human isolates (1/49) (p < 0.001). Amplified fragment length polymorphism (AFLP) revealed three major clusters (A, B, and C) among C. jejuni isolated from humans and poultry. There seems to be a lack of overlap between the major human and chicken clones, which suggests that there may be additional sources for campylobacteriosis other than poultry in Bangladesh.

Campylobacter jejuni colonization and population structure in urban populations of ducks and starlings in New Zealand

A repeated cross-sectional study was conducted to determine the prevalence of Campylobacter spp. and the population structure of C. jejuni in European starlings and ducks cohabiting multiple public access sites in an urban area of New Zealand. The country's geographical isolation and relatively recent history of introduction of wild bird species, including the European starling and mallard duck, create an ideal setting to explore the impact of geographical separation on the population biology of C. jejuni, as well as potential public health implications. A total of 716 starling and 720 duck fecal samples were collected and screened for C. jejuni over a 12 month period. This study combined molecular genotyping, population genetics and epidemiological modeling and revealed: (i) higher Campylobacter spp. isolation in starlings (46%) compared with ducks (30%), but similar isolation of C. jejuni in ducks (23%) and starlings (21%), (ii) significant associations between the isolation of Campylobacter spp. and host species, sampling location and time of year using logistic regression, (iii) evidence of population differentiation, as indicated by F_ST, and host-genotype association with clonal complexes CC ST-177 and CC ST-682 associated with starlings, and clonal complexes CC ST-1034, CC ST-692, and CC ST-1332 associated with ducks, and (iv) greater genetic diversity and genotype richness in ducks compared with starlings. These findings provide evidence that host-associated genotypes, such as the starling-associated ST-177 and ST-682, represent lineages that were introduced with the host species in the 19th century. The isolation of sequence types associated with human disease in New Zealand indicate that wild ducks and starlings need to be considered as a potential public health risk, particularly in urban areas.

We applied molecular epidemiology and population genetics to obtain insights in to the population structure, host-species relationships, gene flow and evolution of Campylobacter jejuni in urban ducks and starlings.

Genotype and antibiotic resistance analyses of Campylobacter isolates from ceca and carcasses of slaughtered broiler flocks

To obtain genetic information about Campylobacter jejuni and Campylobacter coli from broilers and carcasses at slaughterhouses, we analyzed and compared 340 isolates that were collected in 2008 from the cecum right after slaughter or from the neck skin after processing. We performed rpoB sequence-based identification, multilocus sequence typing (MLST), and flaB sequence-based typing; we additionally analyzed mutations within the 23S rRNA and gyrA genes that confer resistance to macrolide and quinolone antibiotics, respectively. The rpoB-based identification resulted in a distribution of 72.0% C. jejuni and 28.0% C. coli. The MLST analysis revealed that there were 59 known sequence types (STs) and 6 newly defined STs. Most of the STs were grouped into 4 clonal complexes (CC) that are typical for poultry (CC21, CC45, CC257, and CC828), and these represented 61.8% of all of the investigated isolates. The analysis of 95 isolates from the cecum and from the corresponding carcass neck skin covered 44 different STs, and 54.7% of the pairs had matching genotypes. The data indicate that cross-contamination from various sources during slaughter may occur, although the majority of Campylobacter contamination on carcasses appeared to originate from the slaughtered flock itself. Mutations in the 23S rRNA gene were found in 3.1% of C. coli isolates, although no mutations were found in C. jejuni isolates. Mutations in the gyrA gene were observed in 18.9% of C. jejuni and 26.8% of C. coli isolates, which included two C. coli strains that carried mutations conferring resistance to both classes of antibiotics. A relationship between specific genotypes and antibiotic resistance/susceptibility was observed.

Antimicrobial resistance profiling and molecular subtyping of Campylobacter spp. from processed turkey

BACKGROUND

Campylobacter is a major cause of human disease worldwide and poultry are identified as a significant source of this pathogen. Most disease in humans is associated with the consumption of contaminated poultry or cross-contamination with other foods. The primary drugs of choice for treatment of human campylobacteriosis include erythromycin and ciprofloxacin. In this study, we investigated the prevalence of resistance to erythromycin and ciprofloxacin in Campylobacter isolates recovered from turkey carcasses at two processing plants in the Upper Midwest US. Further analysis of a subset of isolates was carried out to assess resistance and genotype profiles.

RESULTS

Campylobacter isolates from plant A (n = 439; including 196 C. coli and 217 C. jejuni) and plant B (n = 362, including 281 C. coli and 62 C. jejuni) were tested for susceptibility to ciprofloxacin and erythromycin using agar dilution. C. coli were more frequently resistant than C. jejuni in both plants, including resistance to ciprofloxacin (28% of C. jejuni and 63% of C. coli, plant B; and 11% of C. coli, plant A). Erythromycin resistance was low among C. jejuni (0% plant A and 0.3% plant B) compared to C. coli (41%, plant A and 17%, plant B). One hundred resistant and susceptible isolates were selected for additional antimicrobial susceptibility testing, restriction fragment length polymorphism analysis of the flaA gene (fla typing), and pulsed-field gel electrophoresis (PFGE). Fla-PFGE types obtained (n = 37) were associated with a specific plant with the exception of one type that was isolated from both plants. C. coli isolates (n = 65) were grouped into 20 types, while C. jejuni isolates (n = 35) were grouped into 17 types. Most isolates with identical fla-PFGE patterns shared identical or very similar antimicrobial resistance profiles. PFGE alone and composite analysis using fla-PFGE with resistance profiles separated C. jejuni and C. coli into distinct groups.

CONCLUSION

Ciprofloxacin and erythromycin resistance in Campylobacter recovered from processed turkey occurred more frequently among C. coli than C. jejuni. Fla-PFGE types were associated with a particular species, antimicrobial resistance profiles, and a specific plant. Molecular subtyping in this study provided more information about the relationships among antimicrobial-resistant Campylobacter at the processing level.

Associations between antimicrobial exposure and resistance in fecal Campylobacter spp. from grow-finish pigs on-farm in Alberta and Saskatchewan, Canada

Campylobacter spp. (n = 405), isolated from the feces of apparently healthy grow-finish pigs in 20 herds, were tested for susceptibility to 10 antimicrobials representing seven classes. Twelve percent of the isolates were susceptible to all drugs, while 64% were resistant to two or more antimicrobial classes. Resistance was most common to clindamycin, azithromycin, and erythromycin (71% each), and 10% of the isolates were resistant to ciprofloxacin. An antimicrobial use risk-factor analysis and a variance analysis explored the connection between antimicrobial resistance and the herd. The antimicrobial exposure of each production phase of each herd, through feed and water, was evaluated as a potential risk factor for resistance to macrolides and quinolones. Every 100,000 pig days of macrolide exposure in nursery pigs increased the odds of resistance to macrolides by a factor of 1.3. In contrast, the odds of resistance to a quinolone were nine times higher in Campylobacter from herds without beta-lactam exposure in grow-finish pigs compared with those with exposure. The variance analysis identified remarkably high clustering between isolates within herds; the intraclass correlations for resistances ranged from 0.52 to 0.82. Such extreme clustering demonstrates the potential for herd-level interventions to influence antimicrobial resistance in Campylobacter. The three key findings of this study, i.e., the prevalent resistance to macrolides, the association between macrolide exposure and Campylobacter resistance to macrolides, and the high clustering of resistance within herds, illustrate the need for continued study of antimicrobial-resistant Campylobacter on pig farms and the importance of judicious antimicrobial use in pork production.

Farm-level risk factors for fluoroquinolone resistance in E. coli and thermophilic Campylobacter spp. on finisher pig farms

Logistic regression, supported by other statistical analyses was used to explore the possible association of risk factors with the fluoroquinolone (FQ)-resistance status of 108 pig finisher farms in Great Britain. The farms were classified as 'affected' or 'not affected' by FQ-resistant E. coli or Campylobacter spp. on the basis of isolation of organisms from faecal samples on media containing 1 mg/l FQ. The use of FQ was the most important factor associated with finding resistant E. coli and/or Campylobacter, which were found on 79% (FQ-resistant E. coli) and 86% (FQ-resistant Campylobacter) of farms with a history of FQ use. However, resistant bacteria were also found on 19% (FQ-resistant E. coli) and 54% (FQ-resistant Campylobacter) of farms with no history of FQ use. For FQ-resistant E. coli, biosecurity measures may be protective and there was strong seasonal variation, with more farms found affected when sampled in the summer. For FQ-resistant Campylobacter, the buying-in of grower stock may increase risk and good on-farm hygiene may be protective. The findings suggest that resistant organisms, particularly Campylobacter, may spread between pig farms.

Prevalence of Campylobacter jejuni and Campylobacter coli in market-weight turkeys on-farm and at slaughter

To monitor the effects of feed withdrawal on the prevalence of Campylobacter, market-weight turkeys from six farms were examined before and after perimarketing events (feed withdrawal, transport, and holding at the slaughterhouse). Prior to transport, birds (n = 30 per farm) were slaughtered on-farm, and viscera (crops, duodenum, jejunum, ileum, colon, ceca, gallbladder, and spleen) were removed on the premises. Within ca. 48 h, cohorts (n = 30 per farm) from the same flock were transported to a commercial abattoir, maintained in holding sheds, slaughtered, and the viscera were removed. No differences in the prevalence of Campylobacter spp. were evident when individual flocks were compared pre- and posttransport. However, when data for the six farms were combined, Campylobacter spp. were recovered (pre- versus posttransport) at comparable rates from the duodenum (74.7 versus 74.7%), ileum (87.3 versus 92.7%), ceca (64 versus 57%), colon (86.7 versus 80%), and spleen (0 versus 0%). After feed withdrawal, transport, and holding at the abattoir, there was an overall increase in Campylobacter spp. isolated from the gallbladder at the abattoir (14.7%) when compared with on-farm levels (0%, P < 0.05). When compared with on-farm levels (3%), the overall increase in Campylobacter spp. recovered from the crops of birds at the abattoir (24%) was significant (P < 0.05), which may be associated with a detectable decline in lactic acid in the emptied crop.

A survey of fluoroquinolone resistance in Escherichia coli and thermophilic Campylobacter spp. on poultry and pig farms in Great Britain

AIMS

To estimate the proportions of farms on which broilers, turkeys and pigs were shedding fluoroquinolone (FQ)-resistant Escherichia coli or Campylobacter spp. near to slaughter.

METHODS AND RESULTS

Freshly voided faeces were collected on 89 poultry and 108 pig farms and cultured with media containing 1.0 mg l(-1) ciprofloxacin. Studies demonstrated the specificity of this sensitive method, and both poultry and pig sampling yielded FQ-resistant E. coli on 60% of farms. FQ-resistant Campylobacter spp. were found on around 22% of poultry and 75% of pig farms. The majority of resistant isolates of Campylobacter (89%) and E. coli (96%) tested had minimum inhibitory concentrations for ciprofloxacin of > or =8 mg l(-1). The proportion of resistant E. coli and Campylobacter organisms within samples varied widely.

CONCLUSIONS

FQ resistance is commonly present among two enteric bacterial genera prevalent on pig and poultry farms, although the low proportion of resistant organisms in many cases requires a sensitive detection technique.

SIGNIFICANCE AND IMPACT OF THE STUDY

FQ-resistant bacteria with zoonotic potential appear to be present on a high proportion of UK pig and poultry farms. The risk this poses to consumers relative to other causes of FQ-resistant human infections remains to be clarified.

Polyphasic characterization of Xanthomonas axonopodis pv. allii associated with outbreaks of bacterial blight on three Allium species in the Mascarene archipelago

Based on the number of new reports during the last two decades, bacterial blight of onion (Allium cepa) is considered an emerging disease. The causal agent, Xanthomonas axonopodis pv. allii, is pathogenic to several Allium species after inoculation, but outbreaks worldwide have been primarily reported on onion. We describe a unique epidemiological situation in Réunion Island, France, with concomitant outbreaks on three Allium species, onion, leek (A. porrum), and garlic (A. sativum). There was no host specialization within Allium spp. among strains associated with the three host species. Based on amplified fragment length polymorphism (AFLP) and restriction fragment length polymorphism, strains associated with these outbreaks in Réunion Island were highly related genetically to strains isolated from diseased plant samples and contaminated seed lots in the neighboring island of Mauritius, where the disease has occurred since 1984. All AFLP haplotypes were identified as X. axonopodis pv. allii based on polymerase chain reaction analysis using specific primers, biochemical tests, and/or pathogenicity tests. Two genetically related groups of strains (A and B) that can be distinguished by AFLP, differential utilization of three carbon sources, and xanthomonadin pigment production were detected initially after establishment of the pathogen. In less than 10 years after the establishment of the pathogen there was nearly an extinction of group A strains in Réunion Island, suggesting differences in fitness between strains in the two groups.

Statistical comparison of Campylobacter jejuni subtypes from human cases and environmental sources

AIM

To analyse Campylobacter jejuni typing data to define statistically which potential reservoirs and transmission sources contain isolates that are most similar to one another and to isolates from human infections.

METHODS AND RESULTS

Serotyping and SmaI macrorestriction profiling data for C. jejuni isolates from human campylobacteriosis cases, chicken carcass rinses, duck, sheep, dairy and beef cattle faeces, river water, and sheep, beef and pork offal obtained from a defined rural area of New Zealand were compared using the Czekanowski proportional similarity index. Subtypes of isolates from ruminant animals, whether derived from their faeces or offals, were generally similar to one another. The spectrum of isolate subtypes from human cases was more similar to that from ruminant faeces than the other matrices considered. Isolate subtypes from chicken rinses, pork offal, water and duck faeces were not highly similar to those from other matrices.

CONCLUSIONS

Results from a combination of phenotypic and genotypic approaches suggest that, for this rural population, exposures associated with a rural lifestyle may be significant sources of human campylobacteriosis.

SIGNIFICANCE AND IMPACT OF THE STUDY

The Czekanowski index was applied to subtyping data and supported the greater importance of contact with livestock in campylobacteriosis cases associated with a rural setting, in comparison with urban studies that have identified poultry-related factors.

Role of poultry meat in sporadic Campylobacter infections in Bosnia and Herzegovina: laboratory-based study

AIM

To investigate genetic diversity and specificity of Campylobacter jejuni and Campylobacter coli strains isolated from humans, retail poultry meat, and live farm chickens in Zenica-Doboj Canton, Bosnia and Herzegovina, and identify the role of poultry meat in sporadic Campylobacter infections.

METHODS

We determined the type of Campylobacter species using standard microbiological methods and multiplex polymerase chain reaction (PCR), and performed pulsed field gel-electrophoresis (PFGE) and restriction fragment length polymorphism (RFLP) typing of the flaA gene to investigate genetic diversity among the isolates.

RESULTS

We isolated C jejuni and C coli from 75 (5.2%) of 1453 samples of consecutive outpatients with sporadic diarrhea; from 51 (34.7%) of 147 samples of poultry meat; and from 15 out of 23 farm chicken samples. The proportion of C coli found among human (30.1%), poultry meat (56.9%), and farm chicken isolates (53.3%), was greater than the proportion of C jejuni. Fourteen and 24 PFGE genotypes were identified among 20 C coli and 37 C jejuni isolates, respectively. Identical PFGE genotypes were found in two cases of human and poultry meat isolates and two cases of poultry meat and farm chicken isolates.

CONCLUSION

Only a minority of human Campylobacter isolates shared identical PFGE type with poultry meat isolates. Although poultry is the source of a certain number of human infections, there may be other more important sources. Further research is required to identify the environmental reservoir of Campylobacter spp responsible for causing human disease and the reason for the high prevalence of C coli human infections in this region.

Multilocus sequence typing performed on Campylobacter coli isolates from humans, broilers, pigs and cattle originating in Denmark

AIMS

To assess whether Campylobacter coli isolated from different sources in Denmark constitute separate populations.

METHODS AND RESULTS

Multilocus sequence typing (MLST) was applied to 160 C. coli isolates from animal origin, food products and human cases of gastroenteritis. The isolates were collected in Denmark over a 2-year period. In total, 84 sequence types (STs) were obtained and 57 of these STs were novel to this study. Ten per cent of the isolates possessed STs that were found in both human, poultry and pig isolates. Only 10% of the isolates from pigs shared ST with isolates from humans, and these shared STs were found in poultry isolates as well.

CONCLUSIONS

Great genetic diversity was seen within the Danish C. coli population. Furthermore, we found that the C. coli types isolated from Danish pigs constitute a small fraction of the C. coli causing human disease.

SIGNIFICANCE AND IMPACT OF THE STUDY

C. coli isolates from pigs is presumably not a significant source of human campylobacteriosis in Denmark. The Danish C. coli isolates include 68% STs novel to this study, showing a great diversity compared with studies from other countries.

Diversity of Campylobacter coli genotypes in the lower porcine gastrointestinal tract at time of slaughter

AIMS

To compare the genotypes of Campylobacter coli obtained from the rectal and ileal samples of pigs at the time of slaughter.

METHODS AND RESULTS

Five animals were sampled following slaughter with ileal contents and anal swabs being taken post-evisceration. Swabs were directly plated onto charcoal cefoperazone desoxycholate agar (CCDA) while ileal contents were enriched in CCDA broth. Twenty isolates were picked from each site sampled and all 200 isolates were Camp. coli. Isolates were genotyped using random amplified polymorphic DNA (22 discrete types) and flaA (11 discrete types). Both methods found that 55% of the genotypes were unique to rectal samples. Only one animal yielded the same flaA type from ileal and rectal samples.

CONCLUSIONS

Rectal sampling of pigs yielded a more diverse subset of Camp. coli genotypes than ileal contents, but failed to yield all of the genotypes carried by an individual animal.

SIGNIFICANCE AND IMPACT OF THE STUDY

A small sample of pigs carried a very diverse population of Camp. coli genotypes; and sampling of a single site in the gut will recover only part of this population. Hence, any genotyping studies of Camp. coli in pigs must be interpreted with caution, and epidemiological studies could be confounded by the number of Camp. coli genotypes available.

Molecular typing of Sarcocystis neurona: current status and future trends

Sarcocystis neurona is an important protozoal pathogen because it causes the serious neurological disease equine protozoal myeloencephalitis (EPM). The capacity of this organism to cause a wide spectrum of neurological signs in horses and the broad geographic distribution of observed cases in the Americas drive the need for sensitive, reliable and rapid typing methods to characterize strains. Various molecular methods have been developed and used to diagnose EPM due to S. neurona, to identify S. neurona isolates and to determine the heterogeneity and evolutionary relatedness within this species and related Sarcocystis spp. These methods included sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immuno-fluorescent assay (IFA), slide agglutination test (SAT), SnSAG-specific ELISA, random amplified polymorphic DNA (RAPD), PCR-based restriction fragment length polymorphism (RFLP), amplified fragment length polymorphism (AFLP) fingerprinting, and sequence analysis of surface protein genes, ribosomal genes, microsatellite alleles and other molecular markers. Here, the utility of these molecular methods is reviewed and evaluated with respect to the need for molecular approaches that utilize well-characterized polymorphic, simple, independent, and stable genetic markers. These tools have the potential to add to knowledge of the genetic population structure of S. neurona and to provide new insights into the pathogenesis of EPM and S. neurona epidemiology. In particular, these methods provide new tools to address the hypothesis that particular genetic variants are associated with adverse clinical outcomes (severe pathotypes). The ultimate goal is to utilize them in future studies to improve treatment and prevention strategies.

Comparison of virulence-associated in vitro properties of typed strains of Campylobacter jejuni from different sources

Campylobacter jejuni is a major cause of human diarrhoeal disease, but specific virulence mechanisms have not been well defined. This blinded study was undertaken with 40 C. jejuni isolates from different sources to determine their haemolytic, cytotoxic and adhesion and invasion activities towards mammalian cells. The results were correlated with source of isolation and genetic makeup by amplified fragment length polymorphism (AFLP) typing. The isolates had variable degrees of haemolytic activity against rabbit erythrocytes and cytotoxicity towards CaCo-2, HeLa and Vero cells. The data indicated that the haemolytic and cytotoxic activities were due to separate factors. A range of cytotoxicity was exhibited, whereby some strains had no activity against the target cells and others had activity against all three cell lines. Certain strains had activity against CaCo-2 cells but little or no activity against the other cells, while others exhibited the opposite phenotype. The data suggested that the cytotoxicity assay with the different cell lines may have detected more than one cytotoxin. A wide variation between isolates was observed for both adherence and invasion with all three cell lines, yet, overall, the strains showed a significantly greater invasion capacity for CaCo-2. There was no clear relationship between source of isolation or disease manifestation and possession of statistically significantly higher levels of particular virulence-associated factors although, in some cases, a correlation between cytotoxicity and cell invasion was evident. Five AFLP clusters, each representing two to eleven isolates with similar profiles, were observed at the 90 % similarity level. Some AFLP groups contained isolates with a common serotype, but each group had C. jejuni isolates from more than one source with the exception of group IV, which contained only human isolates. Isolates with high cytotoxic activity against CaCo-2 cells were confined to groups I, III and IV and a group of unrelated strains (U). Group II isolates had uniformly low cytotoxicity. Isolates in groups I, V and U were more invasive for CaCo-2 cells than isolates in groups II, III and IV. The strain differences in cytotoxicity or invasion did not correlate with source of isolation.

Distribution and Genetic Variability Among Campylobacter spp. Isolates from Different Animal Species and Humans in Switzerland

In Switzerland, a national database with 1028 Campylobacter isolates from poultry, pigs, cats, dogs, cattle, humans, zoo animals and water has been created. The database contains the genetic fingerprint and background information of each Campylobacter isolate. Dominant species could be identified in the different sources with a majority of Campylobacter jejuni in poultry (73%), humans (79%), cattle (95%), zoo animals (40%) and water (100%), of Campylobacter coli in pigs (72%), and of Campylobacter upsaliensis/helveticus in cats and dogs (55%). The comparison of three genotyping methods, amplified fragment length polymorphism (AFLP), pulsed field gel electrophoresis and restriction fragment length polymorphism, revealed that AFLP allows discrimination between the different Campylobacter species and is the most appropriate method to distinguish specific strains within the same species. Genotyping analysis demonstrated that the Campylobacter population is heterogeneous among the different sources and that no dominant clone is spread in the country. Genotyping and the resulting database are useful tools to trace back future Campylobacter infections.

Genotyping of Campylobacter coli and C. jejuni from retail chicken meat and humans with campylobacteriosis in Slovenia and Bosnia and Herzegovina

Thermotolerant Campylobacter jejuni and C. coli are one of the major causes of bacterial foodborne enteric infection. Consuming and/or handling poultry meat is the most consistent risk factor, linked to the high prevalence of campylobacters in retail poultry meat. The aim of the present study was to ascertain the genetic diversity and/or possible specificity of thermotolerant Campylobacter isolates according to species (C. coli, C. jejuni), isolation source (retail chicken meat and human clinical samples) and geographic origin (Goriska in Slovenia and Zenica-Doboj Canton in Bosnia and Herzegovina (BIH)). With the pulsed-field gel electrophoresis (PFGE) after SmaI macrorestriction we distinguished 80 PFGE types among 118 strains and CfoI restriction fragment length polymorphism of the amplified flagellin gene (fla-RFLP) gave 12 fla-RFLP types. Beside the higher discriminatory power and strain typeability, PFGE discriminated the C. jejuni and C. coli groups of isolates. A high proportion of C. coli strains was isolated, especially from poultry samples. Identical or very similar PFGE types among the isolates from animal, food and human samples indicate the transmission of C. jejuni and C. coli from the chickens on the farm to the retail chicken meat, as well as possible cross-contamination of retail meat and transmission to humans. However, the identity of the isolates from non-related samples but with identical PFGE and fla-RFLP types should be confirmed with additional typing. Reliable tracing of the source of Campylobacter strains by molecular typing of the chicken meat isolates is therefore very difficult. The reasons include contamination of meat samples with multiple strains, possible cross-contamination and extreme heterogeneity of the isolates (mainly for C. jejuni) on one side and a limited power of the genotyping methods used to distinguish non-related strains on the other side (mainly for C. coli).

The occurrence and characterization of Campylobacter jejuni and C. coli in organic pigs and their outdoor environment

The occurrence and species distribution of thermophilic Campylobacter was investigated in organic outdoor pigs. An increased exposure of outdoor pigs to C. jejuni from the environment may cause a shift from a normal dominance of C. coli to more C. jejuni, which may imply a concern of reduced food safety. Bacteriological methods for determination of Campylobacter excretion level were combined with colony-blot hybridization and real-time PCR for specific detection of C. jejuni in pigs. Campylobacter was isolated from pigs (n=47), paddock environment (n=126) and wildlife (n=44), identified to species by real-time PCR and sub-typed by serotyping (Penner) and pulse-field gel electrophoresis (PFGE) genotyping. All pigs excreted Campylobacter (10(3)-10(7) CFU g(-1) faeces) from the age of 8-13-weeks old. C. jejuni was found in 29% of pigs in three consecutive trials and always in minority to C. coli (0.3-46%). C. jejuni and C. coli were isolated from 10% and 29% of the environmental samples, respectively, while crow-birds and rats harboured C. jejuni. Individual pigs hosted several strains (up to nine serotypes). The paddock environment was contaminated with C. coli serotypes similar to pig isolates, while most of the C. jejuni serotypes differed. C. jejuni isolates of different origin comprised few similar serotypes, just one identical genotype was common between pigs, environment and birds. In conclusion, the occurrence of C. jejuni varied considerably between the three groups of outdoor pigs. Furthermore, transfer of C. jejuni to the outdoor pigs from the nearby environment was not predominant according to the subtype dissimilarities of the obtained isolates.

Helicobacter pullorum in chickens, Belgium

A total of 110 broilers from 11 flocks were tested for Helicobacter pullorum by polymerase chain reaction; positive samples were reexamined with a conventional isolation method. H. pullorum isolates were examined by amplified fragment length polymorphism (AFLP) fingerprinting for interstrain genetic diversity and relatedness. Sixteen isolates from cecal samples from 2 different flocks were obtained. AFLP analysis showed that these isolates and 4 additional isolates from a different flock clustered according to their origin, which indicates that H. pullorum colonization may occur with a single strain that disseminates throughout the flock. Strains isolated from different hosts or geographic sources displayed a distinctive pattern. H. pullorum is present in approximately one third of live chickens in Belgium and may represent a risk to human health.

Delineation of Campylobacter concisus genomospecies by amplified fragment length polymorphism analysis and correlation of results with clinical data

Campylobacter concisus has been as frequently isolated from human diarrhea as the important enteropathogen Campylobacter jejuni, but it also occurs in the feces of healthy individuals. The role of C. concisus in human disease has been difficult to determine, since the species comprises at least two phenotypically indistinguishable but genetically distinct taxa (i.e., genomospecies) that may vary in pathogenicity. We examined 62 C. concisus strains by amplified fragment length polymorphism (AFLP) profiling and correlated the results with clinical data. All C. concisus strains gave unique AFLP profiles, and numerical analysis of these data distributed the strains among four clusters. The clustering was of taxonomic significance: two clusters contained, respectively, the type strain (of oral origin) and a reference strain (from diarrhea) of each of the known genomospecies. Genomospecies 2 strains were more frequently isolated from immunocompetent patients and/or patients without concomitant infections that presented with fever, chronic diarrhea, and gut inflammation than was genomospecies 1, clustering with the type strain of oral origin. Bloody diarrhea was recorded only with C. concisus genomospecies 2 infections. We identified two additional C. concisus genomospecies: genomospecies 3 comprised a single strain from an immunocompetent patient, and genomospecies 4 contained five isolates from severely immunodeficient patients, i.e., organ transplantation recipients or those with hematological malignancies. All genomospecies 4 strains were of the same protein profile group and failed to react with a C. concisus species-specific PCR assay based on 23S rRNA gene sequences: the taxonomic position of this group requires closer investigation. Campylobacter concisus is genetically and taxonomically diverse and contains at least four distinct genomospecies that may exhibit differences in their spectra of virulence potential.

Extended multilocus sequence typing system for Campylobacter coli, C. lari, C. upsaliensis, and C. helveticus

A multilocus sequence typing (MLST) system has been reported previously for Campylobacter jejuni to both differentiate strains and identify clonal lineages. However, sequence variation at the MLST loci prevents its use for closely related Campylobacter species. We describe herein an expanded MLST method to include three clinically relevant Campylobacter species, C. coli, C. lari, and C. upsaliensis, and a fourth Campylobacter species, C. helveticus. The C. coli and C. helveticus methods use the same seven C. jejuni loci (aspA, atpA, glnA, gltA, glyA, pgm, and tkt); however, adk and pgi were substituted for aspA and gltA in C. lari and for gltA and pgm in C. upsaliensis. Multiple C. coli (n = 57), C. lari (n = 20), C. upsaliensis (n = 78), and C. helveticus (n = 9) isolates, representing both clinical and environmental sources, were typed. All four species were genetically diverse: the majority (> 80%) of the isolates had unique sequence types (STs). Using this method, mixed C. lari, C. upsaliensis, and C. helveticus isolates were identified; upon separation, each isolate was shown to contain two strains of the same species with distinct STs. Additionally, the expanded MLST method was able to detect potential lateral transfer events between C. jejuni and either C. coli or C. lari and between C. upsaliensis and C. helveticus. Thus, the expanded MLST method will prove useful in differentiating strains of five Campylobacter species, identifying mixed Campylobacter cultures, and detecting genetic exchange within the genus.