Use of PCR for direct detection of Campylobacter species in bovine feces

Identification of bacterial pathogens in brain abscesses by metagenomic approach using nanopore 16S amplicon sequencing

Brain abscess is medically challenging. In this study, we applied nanopore sequencing for 16S rRNA analysis and investigated its efficacy and diagnostic value for patients with brain abscesses. Genomic DNA was extracted from the pus samples (n = 27) of brain abscess, and 16S rRNA genes were amplified by PCR. Sequencing libraries were generated using a rapid barcoding kit, and the generated reads were analyzed using the EPI2ME16S workflow. A conventional culture study was performed. More sensitive identification of pathogens was made by 16S sequencing, faster than the culture study. The proportion of anaerobic bacteria identified by 16S sequencing was higher (75%) than that obtained by culturing (32%). Polymicrobial infections were identified in 10 cases (40%) by 16S sequencing, while the culture study identified multiple bacteria in only 2 cases (8%). 16S sequencing was useful for identifying the composition of polymicrobial infections, including rare pathogens, and for the initial diagnosis of space-occupying lesions.

Impact of In-Feed versus In-Water Chlortetracycline and Tiamulin Administrations on Fecal Prevalence and Antimicrobial Susceptibilities of Campylobacter in a Population of Nursery Pigs

Antimicrobial resistance (AMR) in bacteria is a major public health concern in the US and around the world. Campylobacter is an important foodborne pathogen that resides in the gut of pigs and is shed in feces, with the potential to be transmitted to humans. In pigs, the oral route, either in-feed or in-water, is by far the most common route of administration of antimicrobials. Because the distribution of the antibiotic in the gut and the dosages are different, the impact of in-feed vs. in-water administration of antibiotics on the development of AMR is likely to be different. Therefore, a study was conducted to compare in-feed vs. in-water administrations of chlortetracycline (CTC) and/or tiamulin on fecal prevalence and AMR profiles of Campylobacter among weaned nursery piglets. A total of 1,296 weaned piglets, allocated into 48 pens (27 piglets per pen), were assigned randomly to six treatment groups: Control (no antibiotic), in-feed CTC, in-water CTC, in-feed tiamulin, in-water tiamulin, or in-feed CTC and tiamulin. Fecal samples were collected randomly from 5 piglets from each pen during the pre-treatment (days 0, 7), treatment (days 14, 21), and post-treatment (days 28, 35) phases. Bacterial isolations and species identifications were conducted by culture and PCR, respectively. The microbroth dilution method with SensititreTM plates was used to determine the antimicrobial susceptibility and resistance of Campylobacter isolates. The results on resistance were interpreted based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cutoff values for Campylobacter. The overall prevalence of Campylobacter was 18.2% (262/1440). Speciation of Campylobacter isolates by PCR indicated the prevalence of only two species: Campylobacter hyointestinalis (17.9%; 258/1440) and C. coli (0.3%; 4/1440). Campylobacter isolates were resistant to tetracycline (98.5%), ciprofloxacin (89.3%), and nalidixic acid (60.3%). Neither the antibiotic nor the route of administration had an effect (p > 0.05) on the prevalence of AMR Campylobacter in the feces of piglets.

Molecular Epidemiological Evidence Implicates Cattle as a Primary Reservoir of Campylobacter jejuni Infecting People via Contaminated Chickens

The study aimed to determine the relative contribution of cattle to the burden of illness in a model agroecosystem with high rates of human campylobacteriosis (≥ 115 cases/100 K), and high densities of cattle, including large numbers of cattle housed in confined feeding operations (i.e., in southwestern Alberta, Canada). To accomplish this, a large-scale molecular epidemiological analysis of Campylobacter jejuni circulating within the study location was completed. In excess of 8000 isolates of C. jejuni from people (n = 2548 isolates), chickens (n = 1849 isolates), cattle (n = 2921 isolates), and water (n = 771 isolates) were subtyped. In contrast to previous studies, the source attribution estimates of clinical cases attributable to cattle vastly exceeded those attributed to chicken (i.e., three- to six-fold). Moreover, cattle were often colonized by C. jejuni (51%) and shed the bacterium in their feces. A large proportion of study isolates were found in subtypes primarily associated with cattle (46%), including subtypes infecting people and those associated with chickens (19%). The implication of cattle as a primary amplifying reservoir of C. jejuni subtypes in circulation in the study location is supported by the strong cattle association with subtypes that were found in chickens and in people, a lack of evidence indicating the foodborne transmission of C. jejuni from beef and dairy, and the large number of cattle and the substantial quantities of untreated manure containing C. jejuni cells. Importantly, the evidence implicated cattle as a source of C. jejuni infecting people through a transmission pathway from cattle to people via the consumption of chicken. This has implications for reducing the burden of campylobacteriosis in the study location and elsewhere.

Prevalence and whole-genome sequence analysis of Campylobacter spp. strains isolated from wild deer and boar in Japan

As a part of risk analysis for consumption of meat from wild animals, the prevalence of Campylobacter spp. in wild deer and boar in Japan was investigated. C. hyointestinalis subsp. hyointestinalis (C. hyointestinalis) was isolated from 2.8% (7/253) of the wild deer and 22.1% (71/321) of the wild boar examined. All 23 wild deer isolates and 141 (72.7%) wild boar isolates carried both chcdt-I and chcdt-II genes. The remaining 53 (27.3%) wild boar isolates had only the chcdt-II gene. By whole-genome sequence analysis, we detected 38-40 virulence- and survival-associated genes (motility, chemotactic, adhesion, invasion, toxin, glycosylation, iron uptake, drug resistance, and stress response), which had been identified in C. jejuni and C. coli. In conclusion, our study highlights C. hyointestinalis as a possible cause of food-borne disease in humans and emphasizes the importance of food hygiene in the processing of wild meats for human consumption.

Campylobacter Express Resistance Array for detecting the presence of fluoroquinolone- and macrolide-resistant Campylobacter jejuni and Campylobacter coli in broiler farms

AIMS

The aim of the study was to develop a microarray-based method for the detection of antibiotic-resistant Campylobacter in broiler farms to decrease the risk of contamination of chicken meat.

METHODS AND RESULTS

A combination of DNA microarray and primer extension for rapid and simultaneous detection of fluoroquinolone- and macrolide-resistant Campylobacter jejuni/Campylobacter coli, termed Campylobacter Express Resistance Array (CAMERA), was used to analyse chicken caecal droppings. CAMERA assays could detect at least 10⁵ colony forming units of C. jejuni/C. coli g^-1 of chicken caecal contents spiked with C. jejuni/C. coli. To compare the CAMERA method and direct culturing method for screening antibiotic-resistant C. jejuni/C. coli in poultry farms, chicken caecal droppings obtained from 42 poultry houses were analysed using both methods. In total, 95.2% of the results (40/42 poultry houses) obtained using the CAMERA and culturing method were identical. In the remaining two poultry houses, the CAMERA could detect the prevalent strain of C. jejuni/C. coli based on results of the culturing method.

CONCLUSIONS

The culturing method required >3 days to isolate and identify antibiotic-resistant C. jejuni/C. coli. In contrast, the CAMERA required only 6 h.

SIGNIFICANCE AND IMPACT OF THE STUDY

This method can facilitate quick screening and control of fluoroquinolone- and macrolide-resistant C. jejuni/C. coli in broiler farms.

Comparative prevalence and diversity of Campylobacter jejuni strains in water and human beings over a 1-year period in southwestern Alberta, Canada

Campylobacter jejuni was isolated from diarrheic people, river water (Oldman River watershed), wastewater, and drinking water over a 1-year period in southwestern Alberta (2008-2009). High rates of campylobacteriosis were observed during the study period (≥115 cases/100K). Infections occurred throughout the year, with a peak in late summer and early autumn. The majority of infections occurred in people living in Lethbridge. Campylobacter jejuni was not isolated from municipal drinking water. In contrast, the bacterium was isolated from untreated and treated wastewater, and river water (all sites). There were no correlations between C. jejuni recovery/detection from water and river flow rates, water turbidity, or fecal coliforms. Campylobacter jejuni recovery from water did not correspond with the peak periods of campylobacteriosis. The bacterium was most commonly isolated downstream of wastewater outfalls; waterfowl congregated at these sites, particularly during the winter months. A comparison of subtypes from people and water revealed that the vast majority of subtypes in water did not correspond to subtypes recovered from diarrheic people, and were linked to waterfowl and other non-human animal sources. We conclude that water-borne C. jejuni did not contribute significantly to the high rates of campylobacteriosis observed in people during the study period.

Association of Broiler Litter Microbiome Composition and Campylobacter Isolation

Infection with Campylobacter species is one of the leading causes of bacterial diarrhea in humans in the US. Chickens, which become colonized on the farm, are important reservoirs of this bacterium. Campylobacter can establish itself in the broiler house via a variety of sources, can survive in the litter of the house, and possibly persist over successive flock cycles. However, the role of the broiler litter microbiome on Campylobacter persistence is not clear. A matched case-control study was conducted to determine whether the broiler litter microbiome composition was associated with Campylobacter isolation within the broiler house. Flocks were classified as cases when either Campylobacter jejuni or Campylobacter coli was isolated in boot sock samples, or as controls otherwise. Case and control flocks were matched at the broiler house level. Composite broiler litter samples were collected and used for DNA extraction and 16S rRNA gene V4 region sequencing. Reads were processed using the DADA2 pipeline to obtain a table of amplicon sequence variants. Alpha diversity and differential bacterial relative abundance were used as predictors of Campylobacter isolation status in conditional logistic regression models adjusting for flock age and sampling season. Beta diversity distances were used as regressors in stratified PERMANOVA with Campylobacter isolation status as predictor, and broiler house as stratum. When Campylobacter was isolated in boot socks, broiler litter microbiome richness and evenness were lower and higher, respectively, without reaching statistical significance. Campylobacter isolation status significantly explained a small proportion of the beta diversity (genus-level Aitchison dissimilarity distance). Clostridium and Anaerostipes were positively associated with Campylobacter isolation status, whereas Bifidobacterium, Anaerosporobacter, and Stenotrophomonas were negatively associated. Our results suggest the presence of bacterial interactions between Campylobacter and the broiler litter microbiome. The negative association of Campylobacter with Bifidobacterium, Anaerosporobacter, and Stenotrophomonas in litter could be potentially exploited as a pre-harvest control strategy.

Bacterial gastroenteritis caused by the putative zoonotic pathogen Campylobacter lanienae: First reported case in Germany

Foodborne campylobacteriosis is the most common cause of human bacterial enteritis in Germany. Campylobacter jejuni and Campylobacter coli are the main causative agents for enteric disease, but a number of other species are involved, including rare ones. These rare Campylobacter spp. are emerging zoonotic pathogens in humans due to increasing international movement of supplies, livestock and people. Campylobacter lanienae was first isolated from healthy abattoir workers in Switzerland and at first its pathogenic potential for humans was considered to be low. Recently, the first case of Campylobacter lanienae -associated human enteritis was reported in Canada. Here, we describe a case of mild Campylobacter lanienae -associated enteritis with subsequent asymptomatic excretion in a butcher. The isolate is available at the TLV strain collection (no. TP00333/18). This first reported case of human Campylobacter lanienae campylobacteriosis in Germany demonstrates the agent's likely zoonotic pathogenicity.

Prospect of microbial food borne diseases in Pakistan: a review

Nowadays food borne illness is most common in people due to their epidemic nature. These diseases affect the human digestive system through bacteria, viruses and parasites. The agents of illness are transmitted in our body through various types of food items, water and uncooked. Pathogens show drastic changes in immunosuppressant people. This review gives general insights to harmful microbial life. Pakistan is a developed country and because of its improper food management, a lot of gastrointestinal problems are noted in many patients. Bacteria are most common agents to spread diarrhoea, villi infection, constipation and dysenteric disease in human and induce the rejection of organ transplant. Enhancement of their lifestyle, properly cooked food should be used and to overcome the outbreak of the diseases.

Rates of fluoroquinolone resistance in domestically acquired Campylobacter jejuni are increasing in people living within a model study location in Canada

Antimicrobial resistance was evaluated in Campylobacter jejuni isolated from 1291 diarrheic people over a 15-year period (2004-2018) in southwestern Alberta, a model location in Canada with a high rate of campylobacteriosis. The prevalence of resistance to chloramphenicol, clindamycin, erythromycin, and gentamicin was low during the examination period (≤4.8%). Resistance to tetracycline remained consistently high (41.6%-65.1%), and resistance was primarily conferred by plasmid-borne tetO (96.2%). Resistance rates to ciprofloxacin and nalidixic acid increased substantially over the examination period, with a maximal fluoroquinolone resistance (FQR) prevalence of 28.9% in 2016. The majority of C. jejuni isolates resistant to ciprofloxacin (93.9%) contained a C257T single nucleotide polymorphism within the gyrA chromosomal gene. Follow up with infected people indicated that the observed increase in FQR was primarily due to domestically acquired infections. Moreover, the majority of FQ-resistant C. jejuni subtypes (82.6%) were endemic in Canada, primarily linked to cattle and chicken reservoirs; 18.4% of FQ-resistant isolates were assigned to three subtypes, predominantly associated with cattle. Study findings indicate the need to prioritize FQR monitoring in C. jejuni infections in Canada and to elucidate the dynamics of the emergence and transmission of resistant C. jejuni strains within and from cattle and chicken reservoirs.

Anthropogenic landscapes increase Campylobacter jejuni infections in urbanizing banded mongoose (Mungos mungo): A one health approach

Background

Campylobacter is a common, but neglected foodborne-zoonotic pathogen, identified as a growing cause of foodborne disease worldwide. Wildlife and domestic animals are considered important reservoirs, but little is known about pathogen infection dynamics in free-ranging mammalian wildlife particularly in sub-Saharan Africa. In countries like Botswana, there is significant overlap between humans and wildlife, with the human population having one of the highest HIV infection rates in the world, increasing vulnerability to infection.

Methodology/Principal findings

We investigated Campylobacter occurrence in archived human fecal samples (children and adults, n = 122, 2011), feces from free-ranging banded mongooses (Mungos mungo, n = 201), surface water (n = 70), and river sediment samples (n = 81) collected in 2017 from the Chobe District, northern Botswana. Campylobacter spp. was widespread in humans (23.0%, 95% CI 13.9–35.4%), with infections dominantly associated with C. jejuni (82.1%, n = 28, 95% CI 55.1–94.5%). A small number of patients presented with asymptomatic infections (n = 6). While Campylobacter spp. was rare or absent in environmental samples, over half of sampled mongooses tested positive (56%, 95% CI 45.6–65.4%). Across the urban-wilderness continuum, we found significant differences in Campylobacter spp. detection associated with the type of den used by study mongooses. Mongooses utilizing man-made structures as den sites had significantly higher levels of C. jejuni infection (p = 0.019) than mongooses using natural dens. Conversely, mongooses using natural dens had overall higher levels of detection of Campylobacter at the genus level (p = 0.001).

Conclusions

These results suggest that landscape features may have important influences on Campylobacter species exposure and transmission dynamics in wildlife. In particular, data suggest that human-modified landscapes may increase C. jejuni infection, a primarily human pathogen, in banded mongooses. Pathogen circulation and transmission in urbanizing wildlife reservoirs may increase human vulnerability to infection, findings that may have critical implications for both public and animal health in regions where people live in close proximity to wildlife.

Campylobacter infections are increasing worldwide but we still know little about the true burden of disease in the developing world, and even less about the role of wildlife and environmental reservoirs in human exposure and infection. Here we take a one-health approach evaluating Campylobacter infections in humans, banded mongooses (Mungos mungo), and the environment. We found evidence of widespread infection with Campylobacter spp. infecting nearly a quarter of sampled adults and children (23.0%, n = 122, 2011), dominantly with C. jejuni. Banded mongooses live in close association with humans in the area and over half of the animals sampled were found positive for Campylobacter spp. (56%, n = 201, 2017). Infection with C. jejuni was greater among mongooses utilizing human-made structures as den sites than those using natural dens. These data suggest that wildlife utilization of anthropogenic landscapes may increase C. jejuni exposure and infection. In turn, pathogen circulation and transmission in urbanizing wildlife reservoirs may increase human vulnerability to infection, particularly impoverished populations, where greater environmental exposures are expected.

Clinically Relevant Campylobacter jejuni Subtypes Are Readily Found and Transmitted within the Cattle Production Continuum but Present a Limited Foodborne Risk

Increasing evidence exists for the role that cattle play in the epidemiology of campylobacteriosis. In this study, the prevalence and distribution of Campylobacter jejuni were longitudinally examined at the subspecies level in the beef cattle production continuum. Animals were subdivided into two groups: those that were not administered antibiotics and those that were administered the antimicrobial growth promoter chlortetracycline and sulfamethazine (AS700). Samples were longitudinally collected throughout the confined feeding operation (CFO) period and during the slaughter process, and C. jejuni was isolated and genotyped to assess subtype richness and to elucidate transmission dynamics from farm to fork. The bacterium was frequently isolated from cattle, and the bacterial densities shed in feces increased over the CFO period. Campylobacter jejuni was also isolated from digesta, hides, the abattoir environment, and carcasses. The administration of AS700 did not conspicuously reduce the C. jejuni densities in feces or within the intestine but significantly reduced the bacterial densities and the diversity of subtypes on abattoir samples. All cattle carried multiple subtypes, including clinically relevant subtypes known to represent a risk to human health. Instances of intra-animal longitudinal transmission were observed. Although clinically relevant subtypes were transmitted to carcasses via direct contact and aerosols, the bacterium could not be isolated nor could its DNA be detected in ground beef regardless of treatment. Although the evidence indicated that beef cattle represent a significant reservoir for C. jejuni, including high-risk subtypes strongly associated with the bovine host, they do not appear to represent a significant risk for direct foodborne transmission. This implicates alternate routes of human transmission.IMPORTANCE Limited information is available on the transmission of Campylobacter jejuni subtypes in the beef production continuum and the foodborne risk posed to humans. Cattle were colonized by diverse subtypes of C. jejuni, and the densities of the bacterium shed in feces increased during the confined feeding period. Campylobacter jejuni was readily associated with the digesta, feces, and hides of cattle entering the abattoir, as well as the local environment. Moreover, C. jejuni cells were deposited on carcasses via direct contact and aerosols, but the bacterium was not detected in the ground beef generated from contaminated carcasses. We conclude that C. jejuni bacterial cells associated with beef cattle do not represent a significant risk through food consumption and suggest that clinically relevant subtypes are transmitted through alternate routes of exposure.

Tetracycline Resistant Campylobacter jejuni Subtypes Emanating from Beef Cattle Administered Non-Therapeutic Chlortetracycline are Longitudinally Transmitted within the Production Continuum but are Not Detected in Ground Beef

The impacts of the antimicrobial growth promoter (AGP), chlortetracycline with sulfamethazine (AS700), on the development of antimicrobial resistance and longitudinal transmission of Campylobacter jejuni within the beef production continuum were empirically determined. Carriage of tetracycline resistance determinants in the enteric bacterial community increased at a greater rate for AS700-treatment cattle. The majority of the bacteria from animals administered AS700 carried tetW. Densities of C. jejuni shed in feces increased over the confined feeding period, and the administration of AS700 did not conspicuously reduce C. jejuni densities in feces or within the intestine. The majority of C. jejuni isolates recovered were resistant to tetracycline, but the resistance rates to other antibiotics was low (≤20.1%). The richness of C. jejuni subtypes recovered from AS700-treated animals that were either resistant or susceptible to tetracycline was reduced, indicating selection pressure due to AGP administration. Moreover, a degree of subtype-specific resistance to tetracycline was observed. tetO was the primary tetracycline resistance determinant conferring resistance in C. jejuni isolates recovered from cattle and people. Clinically-relevant C. jejuni subtypes (subtypes that represent a risk to human health) that were resistant to tetracycline were isolated from cattle feces, digesta, hides, the abattoir environment, and carcasses, but not from ground beef. Thus, study findings indicate that clinically-relevant C. jejuni subtypes associated with beef cattle, including those resistant to antibiotics, do not represent a significant foodborne risk.

Epidemiology of thermotolerant Campylobacter infection in poultry in Nsukka agricultural zone, Nigeria

Backgrond and Aim: Thermotolerant Campylobacter organisms (TCOs) are primary causes of bacterial foodborne gastroenteritis worldwide. Although all warm-blooded animals are susceptible to colonization by TCOs, food-producing animals, especially poultry, are major reservoirs of the infection for transmission to humans. This epidemiological study for thermotolerant Campylobacter infection (TCI) in poultry was, therefore, conducted to determine the prevalence and to identify the risk factors of TCI in 60 randomly selected poultry farms in Nsukka agricultural zone. Materials and Methods: A structured questionnaire was used to elicit information on the farmers' involvement in practices that may aggravate TCI in poultry farms. Isolation of TCOs for the determination of prevalence of the infection was done following standard microbiological protocol. Results: The majority (93.3%) of the farms practiced intensive management system. Farm and individual prevalence of TCI were 78.3% and 19.4%, respectively. The prevalence of 15.7% and 23.6% was recorded for birds reared in urban and rural areas, respectively. Similarly, prevalence rates of 17.2%, 25%, 14.7%, and 24.5% were documented for broiler, layer, male, and female birds, respectively. Major risk factors of TCI found were non-sanitization of drinking water, rearing birds of different ages together, thinning, raising other animals alongside poultry, and overstocking. Conclusion: Overall prevalence of 19.4% is high from public health and food safety points of view. Farmers' participation in the risk factors for TCI is massive. Significant improvement in biosecurity practices in poultry farms in the study area is therefore imperative; to limit TCI in poultry and hence the risk of human infection through the food chain or at the poultry-human interface.

Development and validation of a loop-mediated isothermal amplification assay-a rapid and sensitive detection tool for Mycobacterium avium subsp. paratuberculosis in small ruminants

AIMS

The aim of this study was to design an assay for the identification of Mycobacterium avium subsp. paratuberculosis (MAP) to be used in faeces and milk samples of small ruminants with a loop-mediated isothermal amplification (LAMP) system, as a time-saving and user-friendly method in contrast to real-time PCR.

METHODS AND RESULTS

For the detection of MAP in milk and faeces of small ruminants, we developed a set of primers, specific for the target gene ISMap02. The analytical sensitivity of LAMP, when targeting ISMap02, showed a DNA detection limit of 10 fg μl^-1 . After performing spiking experiments with two MAP reference strains, DSM 44133 and ATCC 19698^T , the limit of detection, using the LAMP protocol described herein were 3·8 MAP CFU per ml milk and 12·5 MAP CFU per gram faeces. All LAMP results during the establishment of the assay were compared to those of the real-time PCR results. An internal amplification control was incorporated into the assay to exclude false-negative results produced and had no significant negative impact on the analytical sensitivity. Validation of the assay was confirmed by testing field samples of faeces and revising the results with real-time PCR.

CONCLUSION

Our study conducted the first MAP detection system with a LAMP targeting ISMap02. Due to the positive results we encourage the use of LAMP in combination with ISMap02, when detecting MAP in faeces samples, as an alternative to targeting other genes as f57 or IS900. Further research on MAP detection in different matrices like raw milk, tissue or sperm with this system is recommended.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides new achievements in MAP diagnostic. Especially small ruminants do not show signs of diarrhoea until the terminal stage of the illness. The greatest task in fighting MAP is to rule out animals, which shed MAP with faeces and milk before showing symptoms of Johne's disease. Worldwide there is a need to eradicate animals, which are low MAP shedders to stop the illness spreading in animal holdings. MAP detection with LAMP is time saving, easy to use, does not need expensive equipment, as, for example, PCR kits and can be used without access to laboratories. The target gene ISMap02 was shown to be a specific insertion element for MAP and is a reliable aim in future MAP detection studies.

Enhanced microbiological surveillance reveals that temporal case clusters contribute to the high rates of campylobacteriosis in a model agroecosystem

Infections by pathogenic Campylobacter species were determined in diarrheic (n = 2,217) and non-diarrheic control (n = 104) people in Southwestern Alberta (SWA), Canada over a 1-year period using specialized and conventional isolation, and direct PCR. Overall, 9.9% of diarrheic individuals were positive for C. jejuni (9.1%), C. upsaliensis (0.6%), and C. coli (0.5%). No C. lari was detected. Four diarrheic individuals were co-infected with C. jejuni and C. coli, and four different individuals were co-infected with C. jejuni and C. upsaliensis. Two control individuals were positive for C. jejuni. Approximately 50% of stools containing C. jejuni and/or C. coli were deemed negative by conventional isolation. Direct PCR for C. jejuni was less effective than culture-based detection. Most C. jejuni infections occurred in people living in the urban centers, but the prevalence of the bacterium was lower in females than males living in urban locations, and both males and females living in rural locations. Although C. jejuni was detected throughout the year, a trend for higher infection rates was observed in the late spring to early fall with a peak in August. Forty-six C. jejuni subtype clusters were identified, including 44 temporal case clusters attributed to 28 subtype groupings. The majority of infections (70.3%) were linked to subtypes associated with beef cattle. We conclude that many occurrences of pathogenic Campylobacter species were not detected by the conventional laboratory methodology, and temporal case clusters of C. jejuni subtypes associated with cattle contribute to the high rates of campylobacteriosis in SWA.

Developments in Rapid Detection Methods for the Detection of Foodborne Campylobacter in the United States

The accurate and rapid detection of Campylobacter spp. is critical for optimal surveillance throughout poultry processing in the United States. The further development of highly specific and sensitive assays to detect Campylobacter in poultry matrices has tremendous utility and potential for aiding the reduction of foodborne illness. The introduction and development of molecular methods such as polymerase chain reaction (PCR) have enhanced the diagnostic capabilities of the food industry to identify the presence of foodborne pathogens throughout poultry production. Further innovations in various methodologies, such as immune-based typing and detection as well as high throughput analyses, will provide important epidemiological data such as the identification of unique or region-specific Campylobacter. Comparable to traditional microbiology and enrichment techniques, molecular techniques/methods have the potential to have improved sensitivity and specificity, as well as speed of data acquisition. This review will focus on the development and application of rapid molecular methods for identifying and quantifying Campylobacter in U.S. poultry and the emergence of novel methods that are faster and more precise than traditional microbiological techniques.

Isolation of emerging Campylobacter species in working farm dogs and their frozen home-killed raw meat diets

We applied 7 culture methods to 50 working farm dog fecal samples and 6 methods to 50 frozen home-killed raw meat diet samples to optimize recovery of a wide range of Campylobacter spp. Culture methods combined filtration, enrichment broths, and agars at 37°C and 42°C in conventional and hydrogen-enriched microaerobic atmospheres. Overall, a prevalence of 62% (31 of 50) and 6% (3 of 50) was detected in dog and meat samples, respectively, based on Campylobacter genus PCR. A total of 356 Campylobacter spp. isolates were recovered from dogs, with successful isolation by individual methods ranging from 2 to 25 dogs. The species detected most commonly were C. upsaliensis and C. jejuni, and less commonly C. coli and C. lari. Species isolated that are rarely reported from dogs included C. rectus, C. lari subsp. concheus, C. volucris, and Helicobacter winghamensis. Six isolates from dogs positive by Campylobacter genus PCR were confirmed, using 16S rRNA sequencing, as Arcobacter cryaerophilus (1) and Arcobacter butzleri (5). C. jejuni multi-locus sequence typing results revealed a diversity of sequence types in working dogs, with several uncommonly reported from other C. jejuni sources in New Zealand. Overall, 20 isolates from 3 meat samples were positive by Campylobacter genus PCR; 1 meat sample was positive for C. jejuni, 1 for C. rectus, and 1 isolate was subsequently identified as A. butzleri. The method using Campylobacter enrichment broth in a hydrogen-enriched environment on nonselective agar resulted in significantly reduced recovery of Campylobacter spp. from both sample types.

Therapeutic administration of enrofloxacin in mice does not select for fluoroquinolone resistance inCampylobacter jejuni

Enrofloxacin is registered for therapeutic use in beef cattle to treat bovine respiratory disease in Canada. A murine model was used to experimentally examine the impact of therapeutic administration of enrofloxacin on fluoroquinolone resistance development in Campylobacter jejuni. Administration of enrofloxacin to mice via subcutaneous injection or per os routes resulted in equivalent levels of bioactive enrofloxacin within the intestine, but bioactivity was short-lived (<48 h after cessation). Enrofloxacin administration did not affect densities of total bacteria, Firmicutes, or Bacteroidetes in digesta and had modest impacts on densities of Enterobacteriaceae. All mice inoculated with C. jejuni NCTC 11168 became persistently colonized by the bacterium. Enrofloxacin reduced C. jejuni cell densities within the cecal and colonic digesta for all treatments, and densities shed in feces as a function of antibiotic duration. None of the C. jejuni isolates recovered from mice after administration of enrofloxacin (n = 260) developed resistance to ciprofloxacin regardless of method or duration of administration. Furthermore, only modest shifts in the minimum inhibitory concentration of the isolates by treatment were noted. The study findings indicate that the risk posed by short-term subcutaneous administration of enrofloxacin for the development of fluoroquinolone resistance in mammals is low.

A Novel Natural Antimicrobial Can Reduce the in vitro and in vivo Pathogenicity of T6SS Positive Campylobacter jejuni and Campylobacter coli Chicken Isolates

Human campylobacteriosis is considered one of the most common foodborne diseases worldwide with poultry identified as the main source of infection accounting for 50-80% of human cases. Highly virulent Campylobacter spp., positive for the Type VI secretion system (T6SS), which have an increased ability to adhere to and invade the host gastrointestinal epithelium are highly prevalent in poultry. Multidrug resistant strains of bacteria are rapidly evolving and therefore, new antimicrobials to supplement animal feed that are able to control Campylobacter species, are in great need. The work presented herein indicates that a novel phenolic antimicrobial, Auranta 3001, is able to reduce the adhesion and invasion of human intestinal epithelial cells (HCT-8) by two T6SS positive chicken isolates, C. jejuni RC039 (p < 0.05) and C. coli RC013 (p < 0.001). Exposure of C. jejuni RC039 and C. coli RC013 to Auranta 3001 downregulated the expression of hcp and cetB genes, known to be important in the functionality of T6SS. Furthermore, the reduced adhesion and invasion is associated with a significant decrease in bacterial motility of both isolates (p < 0.05-p < 0.001) in vitro. Most importantly our in vivo results show that Auranta 3001 is able to reduce cecum colonization levels from log 8 CFU/ml to log 2 CFU/ml for C. jejuni RC039 and from log 7 CFU/ml to log 2 CFU/ml for C. coli RC013. In conclusion, this novel antimicrobial is able to reduce the pathogenic properties of T6SS campylobacters in vitro and also to decrease colonization in vivo.

A Novel Natural Antimicrobial Can Reduce the in vitro and in vivo Pathogenicity of T6SS Positive Campylobacter jejuni and Campylobacter coli Chicken Isolates

Human campylobacteriosis is considered one of the most common foodborne diseases worldwide with poultry identified as the main source of infection accounting for 50-80% of human cases. Highly virulent Campylobacter spp., positive for the Type VI secretion system (T6SS), which have an increased ability to adhere to and invade the host gastrointestinal epithelium are highly prevalent in poultry. Multidrug resistant strains of bacteria are rapidly evolving and therefore, new antimicrobials to supplement animal feed that are able to control Campylobacter species, are in great need. The work presented herein indicates that a novel phenolic antimicrobial, Auranta 3001, is able to reduce the adhesion and invasion of human intestinal epithelial cells (HCT-8) by two T6SS positive chicken isolates, C. jejuni RC039 (p < 0.05) and C. coli RC013 (p < 0.001). Exposure of C. jejuni RC039 and C. coli RC013 to Auranta 3001 downregulated the expression of hcp and cetB genes, known to be important in the functionality of T6SS. Furthermore, the reduced adhesion and invasion is associated with a significant decrease in bacterial motility of both isolates (p < 0.05-p < 0.001) in vitro. Most importantly our in vivo results show that Auranta 3001 is able to reduce cecum colonization levels from log 8 CFU/ml to log 2 CFU/ml for C. jejuni RC039 and from log 7 CFU/ml to log 2 CFU/ml for C. coli RC013. In conclusion, this novel antimicrobial is able to reduce the pathogenic properties of T6SS campylobacters in vitro and also to decrease colonization in vivo.

Antibody-conjugated ferromagnetic nanoparticles with lateral flow test strip assay for rapid detection of Campylobacter jejuni in poultry samples

The aim of this study was to develop a nanoparticle-based cell capture system combined with a lateral flow test strip (LFT) assay for rapid detection of Campylobacter jejuni from poultry samples. The developed assay was bench-marked against the standard modified Charcoal Cefoperazone Deoxycholate Agar (mCCDA) method according to ISO16140:2003 procedures. The synthesized ferromagnetic nanoparticles (FMNs) were modified with glutaraldehyde, then functionalized with polyclonal antibodies for specific C. jejuni capture and concentration from poultry samples. After lysing captured cells, DNA from C. jejuni was amplified by PCR using the primers designed to target the hipO gene, and the PCR amplicons were detected with the lateral flow test strip assay. Following the ISO16140:2003 guidelines, the relative detection limit, and the inclusivity and exclusivity tests were determined. The results showed that the limit of detection (LOD) of the assay was 10⁰ or 1 cfu/ml with C. jejuni in pure culture and 10¹-10² cfu/ml with target cells spiked in poultry sample. In addition, the inclusivity and exclusivity tests were found to be 100%. Using field chicken samples (n = 60), the assay showed relative accuracy, relative specificity, and relative sensitivity of 96.67%, 100% and 93.33%, respectively. The positive predictive values (PPV) and negative predictive values (NPV), and the kappa index of concordance (k) were calculated as 100% and 93.75%, and 0.93, respectively. The developed assay required approximately 3 h to complete and gave results comparable to those analyzed by the standard culture method, which required 5-7 days. The assay is rapid, easy-to-use, and has potential to be directly applied to C. jejuni detection in various categories of poultry samples.

ISMap02 element targeted nested polymerase chain in the detection of Mycobacterium avium subsp. paratuberculosis in fecal samples of cattle and buffaloes

Background and Aim

Johne's disease is chronic granulomatous enteritis which affects ruminants. There are many diagnostic approaches for the detection of Mycobacterium avium subsp. paratuberculosis (MAP) of which molecular detection methods using various elements are less time consuming and more accurate. The present study was conducted using ISMap02 element for nested polymerase chain reaction (nPCR) based detection of MAP in fecal samples. The aim was to test the sensitivity and specificity of the ISMap02 element and also to use this element for the detection of MAP in fecal samples of cattle and buffaloes.

Materials and Methods

A total of 211 fecal samples of cattle and buffaloes from different herds around Ludhiana aged between 2 and 13 years were collected, and DNA extraction was done from these samples. The nPCR was carried out for the detection of MAP in fecal samples.

Results

The ISMap02 element was specific for the detection of MAP only and showed a sensitivity of detection of 7.6 fg/µL of the standard genomic DNA. Among the 211 fecal samples of cattle and buffaloes tested for the ISMap02 element, 18 samples (8.5%) were positive for MAP.

Conclusion

The ISMap02 element is specific and sensitive for the detection of MAP in various samples, and when used in nPCR format, it can increase the sensitivity of detection.

Subtype-Specific Selection for Resistance to Fluoroquinolones but Not to Tetracyclines Is Evident in Campylobacter jejuni Isolates from Beef Cattle in Confined Feeding Operations in Southern Alberta, Canada

Campylobacter jejuni was longitudinally isolated from beef cattle housed in four confined feeding operations (CFOs) in Southern Alberta, Canada, over 18 months. All of the cattle were administered a variety of antimicrobial agents (AMAs) nontherapeutically and metaphylactically during their time in the CFOs. In total, 7,966 C. jejuni isolates were recovered from cattle. More animals were colonized by the bacterium after >60 days in the CFO (interim) than were individuals upon entry at the CFO (arrival). Subtyping and resistance to seven AMAs were determined for 1,832 (23.0%) and 1,648 (20.7%) isolates, respectively. Increases in the proportion of isolates resistant to tetracycline were observed at all four CFOs between sample times and to ciprofloxacin and nalidixic acid at one or more CFOs. The vast majority of isolates resistant to tetracycline carried tetO, whereas ciprofloxacin resistance was predominantly attributed to mutations in the gyrA gene. Although considerable diversity was observed, a majority of C. jejuni isolates belonged to one of five predominant subtype clusters. There was no difference in subtype diversity by CFO, but the population structure differed between sample times. Selection for resistance to ciprofloxacin and nalidixic acid was subtype dependent, whereas selection for resistance to tetracycline was not. The findings indicate that a proportion of cattle entering CFOs carry resistant C. jejuni subtypes, and the characteristics of beef cattle CFOs facilitate transmission/proliferation of diverse subtypes, including those resistant to AMAs, which coupled with the densities of CFOs likely contribute to the high rates of cattle-associated campylobacteriosis in Southern Alberta.IMPORTANCE A small proportion of cattle entering a CFO carry Campylobacter jejuni, including subtypes resistant to AMAs. The large numbers of cattle arriving from diverse locations at the CFOs and intermingling within the CFOs over time, coupled with the high-density housing of animals, the high rates of transmission of C. jejuni subtypes among animals, and the extensive use of AMAs merge to create an ideal situation where the proliferation of diverse antimicrobial-resistant C. jejuni subtypes is facilitated. Considering that Southern Alberta reports high rates of campylobacteriosis in the human population and that many of these clinical cases are due to C. jejuni subtypes associated with cattle, it is likely that the characteristics of beef cattle CFOs favor the propagation of clinically relevant C. jejuni subtypes, including those resistant to medically important AMAs, which constitute a risk to human health.

Prevalence and Antibiotic Resistance against Tetracycline in Campylobacter jejuni and C. coli in Cattle and Beef Meat from Selangor, Malaysia

Campylobacter is a major foodborne pathogen frequently associated with human bacterial gastroenteritis in the world. This study was conducted to determine the prevalence and antibiotic resistance of Campylobacter spp. in the beef food system in Malaysia. A total of 340 samples consisting of cattle feces (n = 100), beef (n = 120) from wet markets and beef (n = 120) from hypermarkets were analyzed for Campylobacter spp. The overall prevalence of Campylobacter was 17.4%, consisting of 33% in cattle fecal samples, 14.2% in raw beef from wet market and 7.5% in raw beef from the hypermarket. The multiplex-polymerase chain reaction (PCR) identified 55% of the strains as C. jejuni, 26% as C. coli, and 19% as other Campylobacter spp. A high percentage of Campylobacter spp. were resistant to tetracycline (76.9%) and ampicillin (69.2%), whilst low resistance was exhibited to chloramphenicol (7.6%). The MAR Index of Campylobacter isolates from this study ranged from 0.09 to 0.73. The present study indicates the potential public health risk associated with the beef food system, hence stringent surveillance, regulatory measures, and appropriate interventions are required to minimize Campylobacter contamination and prudent antibiotic usage that can ensure consumer safety.

Epidemiology of antimicrobial resistant Campylobacter spp. isolated from retail meats in Canada

Campylobacter is an important zoonotic pathogen found in livestock and can cause illness in humans following consumption of raw and undercooked meat products. The objectives of this study were to determine the prevalence of Campylobacter spp. in retail meat (poultry, turkey, pork and beef) purchased in Alberta, Canada and to assess antimicrobial resistance and genetic relatedness of recovered Campylobacter strains with previously isolated strains from clinical and environmental sources. A Comparative Genomic Fingerprinting (CGF) method was used for assessing genetic relatedness of isolates. A total of 606 samples comprising 204, 110, 145 and 147 samples of retail chicken, turkey, ground beef and pork, respectively, were obtained. Campylobacter was isolated from 23.5% (48/204) of chicken samples and 14.2% (8/110) of turkey samples. Pork and beef samples were negative for Campylobacter. Campylobacter jejuni was the most common (94.6%) spp. found followed by C. coli (5.4%). Resistance to tetracycline was found in 48.1% of isolates, followed by resistance to ciprofloxacin (5.5%), nalidixic acid (5.5%), azithromycin (1.78%), and erythromycin (1.78%). All isolates were susceptible to clindamycin, florfenicol, gentamicin and telithromycin. Tetracycline resistance was attributable to the presence of the tetO gene. CGF analysis showed that Campylobacter isolated from poultry meat in this study were genetically related to clinical isolates recovered from human infections and to those isolated from animals and the environment.

Prevalence of mcr-1 in the Cecal Contents of Food Animals in the United States

A survey of 2,003 cecal content samples from chickens, turkeys, cattle, and swine at slaughter facilities in the United States was conducted to estimate the prevalence of the mcr-1 gene conferring resistance to colistin in Enterobacteriaceae Two cecal samples from swine had Escherichia coli with IncI2 plasmids bearing the mcr-1 gene.

Characterizing relationships among fecal indicator bacteria, microbial source tracking markers, and associated waterborne pathogen occurrence in stream water and sediments in a mixed land use watershed

Bed sediments of streams and rivers may store high concentrations of fecal indicator bacteria (FIB) and pathogens. Due to resuspension events, these contaminants can be mobilized into the water column and affect overall water quality. Other bacterial indicators such as microbial source tracking (MST) markers, developed to determine potential sources of fecal contamination, can also be resuspended from bed sediments. The primary objective of this study was to predict occurrence of waterborne pathogens in water and streambed sediments using a simple statistical model that includes traditionally measured FIB, environmental parameters and source allocation, using MST markers as predictor variables. Synoptic sampling events were conducted during baseflow conditions downstream from agricultural (AG), forested (FORS), and wastewater pollution control plant (WPCP) land uses. Concentrations of FIB and MST markers were measured in water and sediments, along with occurrences of the enteric pathogens Campylobacter, Listeria and Salmonella, and the virulence gene that carries Shiga toxin, stx2. Pathogens were detected in water more often than in underlying sediments. Shiga toxin was significantly related to land use, with concentrations of the ruminant marker selected as an independent variable that could correctly classify 76% and 64% of observed Shiga toxin occurrences in water and sediment, respectively. FIB concentrations and water quality parameters were also selected as independent variables that correctly classified Shiga toxin occurrences in water and sediment (54%-87%), and Salmonella occurrences in water (96%). Relationships between pathogens and indicator variables were generally inconsistent and no single indicator adequately described occurrence of all pathogens. Because of inconsistent relationships between individual pathogens and FIB/MST markers, incorporating a combination of FIB, water quality measurements, and MST markers may be the best way to assess microbial water quality in mixed land use systems.

Molecular Epidemiology of Campylobacter coli Strains Isolated from Different Sources in New Zealand between 2005 and 2014

Campylobacteriosis is one of the most important foodborne diseases worldwide and a significant health burden in New Zealand. Campylobacter jejuni is the predominant species worldwide, accounting for approximately 90% of human cases, followed by Campylobacter coli Most studies in New Zealand have focused on C. jejuni; hence, the impact of C. coli strains on human health is not well understood. The aim of this study was to genotype C. coli isolates collected in the Manawatu region of New Zealand from clinical cases, fresh poultry meat, ruminant feces, and environmental water sources, between 2005 and 2014, to study their population structure and estimate the contribution of each source to the burden of human disease. Campylobacter isolates were identified by PCR and typed by multilocus sequence typing. C. coli accounted for 2.9% (n = 47/1,601) of Campylobacter isolates from human clinical cases, 9.6% (n = 108/1,123) from poultry, 13.4% (n = 49/364) from ruminants, and 6.4% (n = 11/171) from water. Molecular subtyping revealed 27 different sequence types (STs), of which 18 belonged to clonal complex ST-828. ST-1581 was the most prevalent C. coli sequence type isolated from both human cases (n = 12/47) and poultry (n = 44/110). When classified using cladistics, all sequence types belonged to clade 1 except ST-7774, which belonged to clade 2. ST-854, ST-1590, and ST-4009 were isolated only from human cases and fresh poultry, while ST-3232 was isolated only from human cases and ruminant sources. Modeling indicated ruminants and poultry as the main sources of C. coli human infection.

IMPORTANCE

We performed a molecular epidemiological study of Campylobacter coli infection in New Zealand, one of few such studies globally. This study analyzed the population genetic structure of the bacterium and included a probabilistic source attribution model covering different animal and water sources. The results are discussed in a global context.

First reported case of Campylobacter lanienae enteritis in a human

Introduction:

Campylobacters are the most frequently identified bacteria causing diarrhoea in humans worldwide. Campylobacter lanienae was isolated for the first time in 2000 from faecal samples of two asymptomatic abattoir workers in Switzerland during a routine hygiene screen, but has never been associated with human disease.

Case presentation:

At hospital admission, the patient reported diarrhoea, lower abdominal cramps, nausea, one episode of bilious vomiting and low-grade fever of 38 °C. The patient was having 10 or more diarrheic stools per day as well as during the night, and had noticed blood mixed with the stools on several occasions. Stool cultures were negative for species of Salmonella and Shigella, Escherichia coli O157:H7 and Yersinia enterocolitica, but were positive for C. lanienae. Identification was made by classical biochemical testing, as well as 16S rRNA gene and cpn60 sequencing. The patient slowly improved without antibiotic treatment and was discharged nine days after admission with complete resolution of symptoms.

Conclusion:

On the whole it seems very likely that C. lanienae was the causative agent. Clinical microbiologists should be aware of this micro-organism which can be identified by phenotypic and molecular methods. The real burden of C. lanienae infection in humans might be underestimated and should be further investigated as a potential cause of human diarrhoea disease.

Use of Pooled Samples for the Detection of Salmonella in Feces by Polymerase Chain Reaction

Many epidemiological studies of Salmonella rely on conventional bacteriological culture methods to detect Salmonella in fecal samples. These culture-based methods are inefficient for epidemiological studies in populations with a low prevalence of Salmonella. The objective of this study was to optimize a protocol that uses pooled Salmonella enrichment broth cultures of bovine feces and polymerase chain reaction (PCR) for the detection of the invA gene of Salmonella in feces. In one field trial, 196 animals were sampled, and all samples were tested by culture, invA PCR on individual samples, invA PCR on pools of 5 samples, and BAX PCR on individual samples. All assays showed a high agreement on individual samples (kappa ≥ 0.75). The invA PCR was run on each of 40 pools and detected 19 of 22 culture-positive pools. In another field trial, 152 samples were taken from 4 dairies, and the invA PCR was performed on pools of 5 samples in addition to bacteriological culture of individual samples. Salmonella was detected in 5 of the 32 pools (7 total positive samples) by both PCR and culture. One pool was PCR-positive but culture-negative. Pooling did not dramatically affect the performance of the invA PCR; most of the culture-positive samples were detected, including all of the samples when there were 4 or more Salmonella colonies on the agar plate. Based on these field trials, invA PCR on pooled samples appears to be an efficient method of Salmonella detection as long as Salmonella loads are not extremely low.

Development of a Polymerase Chain Reaction Assay for the Detection of Antibiotic Resistance Genes in Community DNA

Many methods are used to detect antibiotic resistance genes in samples. The objective of the study reported here was to compare polymerase chain reaction (PCR) analysis of community DNA with fecal culturing for detecting antibiotic resistance genes in cattle samples. In the laboratory-based portion of this study, known concentrations of an Escherichia coli strain with 3 antibiotic resistance genes ( cmy-2, flo, and cat) were added to feces from dairy cattle. These genes were used to assess the effect of various primer pairs, chromosomally versus plasmid-encoded genes, and gene copy number on the sensitivity of PCR amplification. Gene-specific PCR amplification was performed on the community DNA extracted from the feces. Feces were cultured for the inoculated strain. In the field-based portion of the study, 80 cattle fecal samples of unknown gene status were compared by use of similar methods. Culture and PCR amplification from community DNA extractions produced variable results, and this variability was most noticeable at dilutions that approached the detection limit of the assay. Typically, PCR amplification had a higher sensitivity than did culture for detecting the gene of interest. However, the sensitivity of culture was improved by plating on selective media containing antibiotics. The community DNA approach enables assessment of bacterial communities in complex samples such as feces, a task that can be prohibitive by budget or time constraints associated with culture methods. Through a strategic combination of culture and community DNA approaches, the relationship between specific selection pressures and the persistence and dissemination of specific resistance genes can be elucidated.

Diversity and relatedness of Shiga toxin-producing Escherichia coli and Campylobacter jejuni between farms in a dairy catchment

The aim of this study was to examine the population structure, transmission and spatial relationship between genotypes of Shiga toxin-producing Escherichia coli (STEC) and Campylobacter jejuni, on 20 dairy farms in a defined catchment. Pooled faecal samples (n = 72) obtained from 288 calves were analysed by real-time polymerase chain reaction (rtPCR) for E. coli serotypes O26, O103, O111, O145 and O157. The number of samples positive for E. coli O26 (30/72) was high compared to E. coli O103 (7/72), O145 (3/72), O157 (2/72) and O111 (0/72). Eighteen E. coli O26 and 53 C. jejuni isolates were recovered from samples by bacterial culture. E. coli O26 and C. jejuni isolates were genotyped using pulsed-field gel electrophoresis and multilocus sequence typing, respectively. All E. coli O26 isolates could be divided into four clusters and the results indicated that E. coli O26 isolates recovered from calves on the same farm were more similar than isolates recovered from different farms in the catchment. There were 11 different sequence types of C. jejuni isolated from the cattle and 22 from water. An analysis of the population structure of C. jejuni isolated from cattle provided evidence of clustering of genotypes within farms, and among groups of farms separated by road boundaries.

Temporal variation in the prevalence and species richness of Campylobacter spp. in a prairie watershed impacted by urban and agricultural mixed inputs

Campylobacter spp. are a substantial cause of gastroenteritis worldwide. Human infection can result from ingestion of contaminated food or water from a variety of sources, including the consumption of fresh produce that is contaminated with the pathogen via the use of contaminated irrigation water. Using molecular methods, we investigated the occurrence of Campylobacter in the Qu’Appelle River watershed, an important source of irrigation water for vegetable producers in southern Saskatchewan, Canada. Water samples were collected from 7 sampling sites from April to September 2009 (145 samples), and from 5 sampling sites from May to October 2013 (116 samples). Campylobacter was detected in 57% and 16% of the samples collected in 2009 and 2013, respectively. Campylobacter detection was highest in May and June for both sampling years. In 2009, the predominant species were Campylobacter lari and Campylobacter jejuni, with prevalences of 84% and 41%, respectively. Other Campylobacter spp. were detected less frequently. Only C. lari was detected in 2013. The results in 2009 demonstrate the species richness of Campylobacter in water sources within the watershed. The occurrence of Campylobacter in the study area also underscores the importance of monitoring irrigation water used to irrigate fresh produce from a public health prospective.

Noninvasive method of DNA isolation from fecal epithelial tissue of dairy animals

A novel noninvasive genomic DNA isolation protocol from fecal tissue, by the proteinase K digestion and guanidine hydrochloride extraction method, was assessed for the genotyping of cattle and buffalo. The epithelial tissues present on the surface of the feces were used as source for isolation of genomic DNA. The DNA isolated from fecal tissue was found to be similar as those obtained from other body tissues such as skin, brain, liver, kidney, and muscle. The quality of DNA was checked by agarose gel electrophoresis and polymerase chain reaction (PCR). We successfully amplified a 320 bp MHC class II DRB gene and a 125 bp mt-DNA D-loop region from isolated genomic DNA of cattle. Thus, the DNA isolated using this method was suitable for common molecular biology methods, such as restriction enzyme digestion and genotyping of dairy animals through PCR.

Detection of Campylobacter in human faecal samples in Fiji

INTRODUCTION

Data on campylobacteriosis in developed countries are well documented; in contrast, few studies on campylobacteriosis have been conducted in developing countries. This study was undertaken to test for Campylobacter in human faecal samples sent to the two major pathology laboratories in Fiji.

METHODS

A total of 408 diarrhoeal faecal samples were collected from the two major hospital pathology laboratories in Central Fiji (Suva) and Western Fiji (Lautoka) between December 2012 and February 2013 and from June to July 2013. Samples were analysed for the presence of Campylobacter using polymerase chain reaction (PCR) based methods.

RESULTS

Campylobacter was detected in 241/408 (59.1%) of samples tested using PCR. Samples from children aged less than five accounted for 21.6% of positive cases.

DISCUSSION

Campylobacter was detected in 59.1% of diarrhoeal samples collected from the two main laboratories in Fiji. A high proportion of children under five years with Campylobacter has been reported in other countries and could be due to parents being more likely to seek medical attention. Further studies are required to confirm the species of Campylobacter that are predominantly associated with gastroenteritis in Fiji.

Prevalence and diversity of Campylobacter species in Saskatchewan retail ground beef

The primary objective of this study was to investigate the prevalence of Campylobacter spp. DNA by PCR in retail ground beef sold in Saskatchewan, Canada, and to identify the presence of individual Campylobacter species (C. coli, C. curvus, C. fetus, C. hyointestinalis, C. jejuni, C. rectus, and C. upsaliensis) using real-time quantitative PCR (qPCR). Secondary objectives were to assess potential differences in the prevalence of Campylobacter between ground beef offered for sale during cold and warm seasons as well as that offered for sale fresh and frozen, to investigate any association between the presence of Campylobacter spp. DNA and E. coli and/or aerobic bacterial counts, and finally to compare the prevalence of Campylobacter spp. DNA in ground beef originating from different production and retail environments. Out of the 309 total samples included in the study, 50 (16.2%) samples tested positive for Campylobacter spp. DNA, while 49 (15.9%) samples were determined positive for up to five individual species. Collectively, these assays determined that 14 (4.5%) samples were positive for C. coli, 11 (3.6%) for C. curvus, 6 (1.9%) for C. fetus, 24 (7.8%) for C. hyointestinalis, 12 (3.9%) for C. jejuni, 6 (1.9%) for C. rectus, and 9 (2.9%) for C. upsaliensis. There were 27 (8.7%) samples that were positive at the genus level that did not test positive for any of the seven Campylobacter species investigated (suggesting an alternate Campylobacter species). Also, 26 (8.4%) samples generated positive results by one of the species-specific qPCR assays, but returned no product in the conventional genus-level assay (suggesting a higher sensitivity for the species-specific qPCR assays). There was no significant association between the presence of Campylobacter spp. in Saskatchewan retail ground beef and any of the investigated risk factors.

Rapid detection and differentiation of important Campylobacter spp. in poultry samples by dot blot and PCR

The detection of Campylobacter, the most commonly reported cause of foodborne gastroenteritis in the European Union, is very important for human health. The most commonly recognised risk factor for infection is the handling and/or consumption of undercooked poultry meat. The methods typically applied to evaluate the presence/absence of Campylobacter in food samples are direct plating and/or enrichment culture based on the Horizontal Method for Detection and Enumeration of Campylobacter spp. (ISO 10272-1B: 2006) and PCR. Molecular methods also allow for the detection of cells that are viable but cannot be cultivated on agar media and that decrease the time required for species identification. The current study proposes the use of two molecular methods for species identification: dot blot and PCR. The dot blot method had a sensitivity of 25 ng for detection of DNA extracted from a pure culture using a digoxigenin-labelled probe for hybridisation; the target DNA was extracted from the enrichment broth at 24 h. PCR was performed using a pair of sensitive and specific primers for the detection of Campylobacter jejuni and Campylobacter coli after 24 h of enrichment in Preston broth. The initial samples were contaminated by 5 × 10 C. jejuni cells/g and 1.5 × 10(2)C. coli cells/g, thus the number of cells present in the enrichment broth at 0 h was 1 or 3 cell/g, respectively.

Isolation of a Campylobacter lanienae-like bacterium from laboratory chinchillas (Chinchilla laniger)

Routine necropsies of 27 asymptomatic juvenile chinchillas revealed a high prevalence of gastric ulcers with microscopic lymphoplasmacytic gastroenteritis and typhlocolitis. Polymerase chain reaction (PCR) analysis using Campylobacter genus-specific partial 16S rRNA primers revealed the presence of Campylobacter spp. DNA in the faeces of 12 of 27 animals (44.4%). Species-specific partial 16S rRNA PCR and sequencing confirmed that these animals were colonized with Campylobacter lanienae, a gram-negative, microaerophilic bacterium that was first identified on routine faecal screening of slaughterhouse employees and subsequently isolated from faeces of livestock. Campylobacter lanienae was isolated from the faeces of six PCR-positive animals and identified with species-specific PCR and full 16S rRNA sequencing. Phylogenetic analysis showed that these isolates clustered with C. lanienae strain NCTC 13004. PCR analysis of DNA extracted from gastrointestinal tissues revealed the presence of C. lanienae DNA in the caecum and colon of these chinchillas. Gastrointestinal lesions were scored and compared between C. lanienae-positive and C. lanienae-negative animals. There was no correlation between colonization status and lesion severity in the stomach, liver, duodenum, or colon. Possible routes of C. lanienae infection in chinchillas could include waterborne transmission and faecal-oral transmission from wild mice and rats or livestock. Based on these findings, the authors conclude that C. lanienae colonizes the lower bowel of chinchillas in the absence of clinical disease. This is the first report of C. lanienae in any rodent species. Campylobacter lanienae isolates from different mammalian species demonstrate heterogeneity by 16S rRNA sequence comparison. Analysis using rpoB suggests that isolates and clones currently identified as C. lanienae may represent multiple species or subspecies.

Comparative variation within the genome of Campylobacter jejuni NCTC 11168 in human and murine hosts

Campylobacteriosis incited by C. jejuni is a significant enteric disease of human beings. A person working with two reference strains of C. jejuni National Collection of Type Cultures (NCTC) 11168 developed symptoms of severe enteritis including bloody diarrhea. The worker was determined to be infected by C. jejuni. In excess of 50 isolates were recovered from the worker's stool. All of the recovered isolates and the two reference strains were indistinguishable from each other based on comparative genomic fingerprint subtyping. Whole genome sequence analysis indicated that the worker was infected with a C. jejuni NCTC 11168 obtained from the American Type Culture Collection; this strain (NCTC 11168-GSv) is the genome sequence reference. After passage through the human host, major genetic changes including indel mutations within twelve contingency loci conferring phase variations were detected in the genome of C. jejuni. Specific and robust single nucleotide polymorphism (SNP) changes in the human host were also observed in two loci (Cj0144c, Cj1564). In mice inoculated with an isolate of C. jejuni NCTC 11168-GSv from the infected person, the isolate underwent further genetic variation. At nine loci, mutations specific to inoculated mice including five SNP changes were observed. The two predominant SNPs observed in the human host reverted in mice. Genetic variations occurring in the genome of C. jejuni in mice corresponded to increased densities of C. jejuni cells associated with cecal mucosa. In conclusion, C. jejuni NCTC 11168-GSv was found to be highly virulent in a human being inciting severe enteritis. Host-specific mutations in the person with enteritis occurred/were selected for in the genome of C. jejuni, and many were not maintained in mice. Information obtained in the current study provides new information on host-specific genetic adaptation by C. jejuni.

Campylobacter jejuni colonization is associated with a dysbiosis in the cecal microbiota of mice in the absence of prominent inflammation

Background

Campylobacter jejuni causes enterocolitis in humans, but does not incite disease in asymptomatic carrier animals. To survive in the intestine, C. jejuni must successfully compete with the microbiota and overcome the host immune defense. Campylobacter jejuni colonization success varies considerably amongst individual mice, and we examined the degree to which the intestinal microbiota was affected in mice (i.e. a model carrier animal) colonized by C. jejuni at high relative to low densities.

Methods

Mice were inoculated with C. jejuni or buffer, and pathogen shedding and intestinal colonization were measured. Histopathologic scoring and quantification of mRNA expression for α-defensins, toll-like receptors, and cytokine genes were conducted. Mucosa-associated bacterial communities were characterized by two approaches: multiplexed barcoded pyrosequencing and terminal restriction fragment length polymorphism analysis.

Results

Two C. jejuni treatments were established based on the degree of cecal and colonic colonization; C. jejuni Group A animals were colonized at high cell densities, and C. jejuni Group B animals were colonized at lower cell densities. Histological examination of cecal and colonic tissues indicated that C. jejuni did not incite visible pathologic changes. Although there was no significant difference among treatments in expression of mRNA for α-defensins, toll-like receptors, or cytokine genes, a trend for increased expression of toll-like receptors and cytokine genes was observed for C. jejuni Group A. The results of the two methods to characterize bacterial communities indicated that the composition of the cecal microbiota of C. jejuni Group A mice differed significantly from C. jejuni Group B and Control mice. This difference was due to a reduction in load, diversity and richness of bacteria associated with the cecal mucosa of C. jejuni Group A mice.

Conclusions

High density colonization by C. jejuni is associated with a dysbiosis in the cecal microbiota independent of prominent inflammation.

Prevalence of Campylobacter spp. relative to other enteric pathogens in grow-finish pigs with diarrhea

Salmonella spp., Lawsonia intracellularis, and Brachyspira spp. are pathogens commonly associated with diarrhea in growing and finishing pigs. Brachyspira spp. infection has recently reemerged as a significant concern due to an increase in the incidence of swine dysentery; however, the mechanisms underlying this increase in dysentery remain largely unknown. Pigs are also well-recognized as potential carriers of Campylobacter spp., particularly Campylobacter coli, yet enteric disease in swine associated with infection by these bacteria is considered uncommon and diagnosis has historically been based upon exclusion of other causes. Accordingly, Campylobacter culture is often excluded in routine diagnostic testing of cases of porcine enterocolitis and the incidence of infection is therefore largely unknown. In this study, feces from 155 cases of clinical diarrhea in grow-finish pigs submitted to the Iowa State University Veterinary Diagnostic Laboratory were cultured for Campylobacter spp. in addition to other testing as indicated for routine diagnostic investigation. Campylobacter culture was positive from 82.6% (128/155) of samples with C. coli accounting for 75% of isolates and Campylobacter jejuni for the remaining 25%. In 14.8% (23/155) of cases a Campylobacter spp. was the sole infectious agent detected; however, there was no association with any particular Campylobacter spp. Interestingly, for those cases with a laboratory diagnosis of Brachyspira-associated disease, 100% (15/15) were also culture positive for Campylobacter spp. suggesting a possible interrelationship between these bacteria in the pig gut. No association was noted between Campylobacter culture results and infection with either Salmonella spp. or L. intracellularis.

Development and application of a real-time polymerase chain reaction method for Campylobacter jejuni detection

AIM: To develop a real-time polymerase chain reaction (PCR) method to detect and quantify Campylobacter jejuni (C. jejuni) from stool specimens.

METHODS: Primers and a probe for real-time PCR were designed based on the specific DNA sequence of the hipO gene in C. jejuni. The specificity of the primers and probe were tested against a set of Campylobacter spp. and other enteric pathogens. The optimal PCR conditions were determined by testing a series of conditions with standard a C. jejuni template. The detection limits were obtained using purified DNA from bacterial culture and extracted DNA from the stool specimen. Two hundred and forty-two specimens were analyzed for the presence of C. jejuni by direct bacterial culture and real-time PCR.

RESULTS: The optimal PCR system was determined using reference DNA templates, 1 × uracil-DNA glycosylase, 3.5 mmol/L MgCl₂, 1.25 U platinum Taq polymerase, 0.4 mmol/L PCR nucleotide mix, 0.48 μmol/L of each primer, 0.2 μmol/L of probe and 2 μL of DNA template in a final volume of 25 μL. The PCR reaction was carried as follows: 95 °C for 4 min, followed by 45 cycles of 10 s at 95 °C and 30 s at 59 °C. The detection limit was 4.3 CFU/mL using purified DNA from bacterial culture and 10³ CFU/g using DNA from stool specimens. Twenty (8.3%, 20/242) C. jejuni strains were isolated from bacterial culture, while 41 (16.9%, 41/242) samples were found to be positive by real-time PCR. DNA sequencing of the PCR product indicated the presence of C. jejuni in the specimen. One mixed infection of C. jejuni and Salmonella was detected in one specimen and the PCR test for this specimen was positive.

CONCLUSION: The sensitivity of detection of C. jejuni from stool specimens was much higher using this PCR assay than using the direct culture method.

Distribution of colonization and antimicrobial resistance genes in Campylobacter jejuni isolated from chicken

Campylobacter jejuni is an important worldwide foodborne pathogen commonly found as a commensal organism in poultry that can reach high numbers within the gut after colonization. Although information regarding some genes involved in colonization is available, little is known about their distribution in strains isolated specifically from chickens and whether there is a linkage between antimicrobial resistance (AMR) and colonization genes. To assess the distribution and relevance of genes associated with chicken colonization and AMR, a C. jejuni microarray was created to detect 254 genes of interest in colonization and AMR including variants. DNA derived from chicken-specific Campylobacter isolates collected in 2003 (n=29) and 2008 (n=28) was hybridized to the microarray and compared. Hybridization results showed variable colonization-associated gene presence. Acquired AMR genes were low in prevalence whereas chemotaxis receptors, arsenic resistance genes, as well as genes from the cell envelope and flagella functional groups were highly variable in their presence. Strains clustered into two groups, each linked to different control strains, 81116 and NCTC11168. Clustering was found to be independent of collection time. We also show that AMR weakly associated with the CJ0628 and arsR genes. Although other studies have implicated numerous genes associated with C. jejuni chicken colonization, our data on chicken-specific isolates suggest the opposite. The enormous variability in presumed colonization gene prevalence in our chicken isolates suggests that many are of lesser importance than previously thought. Alternatively, this also suggests that combinations of genes may be required for natural colonization of chicken intestines.