Easy-to-use rapid test for direct detection of Campylobacter spp. in chicken feces

Lateral flow assay of pathogenic viruses and bacteria in healthcare

Healthcare-associated pathogenic viruses and bacteria can have a serious impact on human health and have attracted widespread global attention. The lateral flow assay is a unidirectional detection based on the binding of a target analyte and a bioreceptor on the device via lateral flow. With incredible advantages over traditional chromatographic methods, such as rapid detection, ease of manufacture and cost effectiveness, these test strips are increasingly considered the ideal form for point-of-care applications. This review explores lateral flow assays for pathogenic viruses and bacteria, with a particular focus on methodologies, device components, construction methods, and applications. We anticipate that this review could provide exciting opportunities for developing new lateral flow devices for pathogens and advance related healthcare applications.

Gold Nanoparticle and Polymerase Chain Reaction (PCR)-Based Colorimetric Assay for the Identification of Campylobacter spp. in Chicken Carcass

Campylobacteriosis is a common cause of gastrointestinal disease. In this study, we suggest a general strategy of applying gold nanoparticles (AuNPs) in colorimetric biosensors to detect Campylobacter in chicken carcass. Polymerase chain reaction (PCR) was utilized for the amplification of the target genes, and the thiolated PCR products were collected. Following the blending of colloid AuNPs with PCR products, the thiol bound to the surface of AuNPs, forming AuNP-PCR products. The PCR products had a sufficient negative charge, which enabled AuNPs to maintain a dispersed formation under electrostatic repulsion. This platform presented a color change as AuNPs aggregate. It did not need additional time and optimization of pH for PCR amplicons to adhere to the AuNPs. The specificity of AuNPs of modified primer pairs for mapA from Campylobacter jejuni and ceuE from Campylobacter coli was activated perfectly (C. jejuni, p-value: 0.0085; C. coli, p-value: 0.0239) when compared to Salmonella Enteritidis and Escherichia coli as non-Campylobacter species. Likewise, C. jejuni was successfully detected from artificially contaminated chicken carcass samples. According to the sensitivity test, at least 15 ng/μL of Campylobacter PCR products or 1×10³ CFU/mL of cells in the broth was needed for the detection using the optical method.

Point-of-Care Diagnostics for Farm Animal Diseases: From Biosensors to Integrated Lab-on-Chip Devices

Zoonoses and animal diseases threaten human health and livestock biosecurity and productivity. Currently, laboratory confirmation of animal disease outbreaks requires centralized laboratories and trained personnel; it is expensive and time-consuming, and it often does not coincide with the onset or progress of diseases. Point-of-care (POC) diagnostics are rapid, simple, and cost-effective devices and tests, that can be directly applied on field for the detection of animal pathogens. The development of POC diagnostics for use in human medicine has displayed remarkable progress. Nevertheless, animal POC testing has not yet unfolded its full potential. POC devices and tests for animal diseases face many challenges, such as insufficient validation, simplicity, and portability. Emerging technologies and advanced materials are expected to overcome some of these challenges and could popularize animal POC testing. This review aims to: (i) present the main concepts and formats of POC devices and tests, such as lateral flow assays and lab-on-chip devices; (ii) summarize the mode of operation and recent advances in biosensor and POC devices for the detection of farm animal diseases; (iii) present some of the regulatory aspects of POC commercialization in the EU, USA, and Japan; and (iv) summarize the challenges and future perspectives of animal POC testing.

A Rapid LAMP-Based Method for Screening Poultry Samples for Campylobacter Without Enrichment

Campylobacter is the most prominent bacterium associated with foodborne disease and the majority of human infection cases are attributed to chicken. Rapid methods capable of determining the Campylobacter status of poultry products in a short time are needed in today's fast-paced food supply chain. In this study, we developed and evaluated an easy to perform, rapid and robust method for direct detection of Campylobacter in poultry carcasses based on loop-mediated isothermal DNA AMPlification (LAMP). The method does not require bacterial culture or DNA purification and generates results in just an hour. A total of 171 swabs from chicken and turkey slaughter houses were analyzed in parallel by both LAMP and conventional culture-based enumeration methods to evaluate the performance of the rapid method. Campylobacter was detected by LAMP in 100% of swabs with an enumeration result of ≥800 cfu/swab, and 98.6% (69 out of 70) of samples reported as negative by enumeration (≤10 cfu/swab) were also negative by LAMP. The method is also suitable for analysis of boot swabs from poultry houses, and therefore it represents a convenient screening tool that can be implemented on farm, at slaughter houses, processing plants or retail, to help with the control of Campylobacter contamination throughout the food supply chain. The inclusion of an internal amplification control prevents any potential false negative results due to DNA amplification inhibitors that might be present in the sample.

Advanced biosensors for detection of pathogens related to livestock and poultry

Infectious animal diseases caused by pathogenic microorganisms such as bacteria and viruses threaten the health and well-being of wildlife, livestock, and human populations, limit productivity and increase significantly economic losses to each sector. The pathogen detection is an important step for the diagnostics, successful treatment of animal infection diseases and control management in farms and field conditions. Current techniques employed to diagnose pathogens in livestock and poultry include classical plate-based methods and conventional biochemical methods as enzyme-linked immunosorbent assays (ELISA). These methods are time-consuming and frequently incapable to distinguish between low and highly pathogenic strains. Molecular techniques such as polymerase chain reaction (PCR) and real time PCR (RT-PCR) have also been proposed to be used to diagnose and identify relevant infectious disease in animals. However these DNA-based methodologies need isolated genetic materials and sophisticated instruments, being not suitable for in field analysis. Consequently, there is strong interest for developing new swift point-of-care biosensing systems for early detection of animal diseases with high sensitivity and specificity. In this review, we provide an overview of the innovative biosensing systems that can be applied for livestock pathogen detection. Different sensing strategies based on DNA receptors, glycan, aptamers and antibodies are presented. Besides devices still at development level some are validated according to standards of the World Organization for Animal Health and are commercially available. Especially, paper-based platforms proposed as an affordable, rapid and easy to perform sensing systems for implementation in field condition are included in this review.

Relative cost-effectiveness of a norovirus vaccine in the deployed military setting compared to a vaccine against Campylobacter sp., ETEC, and Shigella sp

Norovirus (NoV) has been identified as a significant cause of acute gastrointestinal illness among deployed military troops. We conducted a cost-effectiveness analysis for the use of a NoV vaccine in the military using a previously developed model that evaluated vaccines for ETEC, Campylobacter, and Shigella for prevention of non-outbreak associated travelers' diarrhea. Under conservative assumptions, acquisition of a NoV vaccine by the Department of Defense is estimated to result in a cost-effectiveness ratio per duty day lost to illness (CERDDL) of $1344 compared to a CERDDL of $776, $800, and $1275 for ETEC, Campylobacter sp., and Shigella sp., respectively compared to current management strategies. The absolute value of avoiding a duty day lost is likely to vary under different scenarios, and further study is needed to evaluate how improved diagnostics and prevention of outbreaks may impact the relative value of this vaccine. Overall, this study demonstrates the utility of a previously established evidence-based decision tool for prioritization of vaccine acquisition in an important target population.

Rapid monitoring of Campylobacter in high-shedding flocks for targeted disease control

Broilers excreting Campylobacter spp. at high levels (>7 log CFU/g of feces) were described in the Dutch Campylobacter Risk Management and Assessment project as an important source of carcass contamination. The researchers concluded that the risk of infection to humans could be economically and efficiently minimized by eliminating these flocks from fresh poultry meat chains. In the present study, we evaluated a simple and rapid gold-labeled immunosorbent assay (GLISA) for the identification of Campylobacter spp. in flocks shedding high levels of the pathogen. Results were obtained within 2 h. Pooled samples from 102 of the 114 Campylobacter-positive flocks produced positive results, resulting in a test sensitivity of 89.5% (95% confidence interval, 82.6 to 94.2%) and a test specificity of 94.5% (86.7 to 98.2%). Given a GLISA detection limit of 7.3 log CFU/g of feces, nearly all Campylobacter-positive flocks were identified as "high shedders." Therefore, reduction of the incidence of Campylobacter infections by elimination of high-shedding flocks from fresh meat production is an unrealistic approach. Under the constraints given, a reduction in the incidence of Campylobacter spp. in Austria will require either improved hygiene or an intensive carcass decontamination strategy in fresh meat production facilities.

Detection of antibodies to Campylobacter in humans using enzyme-linked immunosorbent assays: a review of the literature

Campylobacteriosis is the most common cause of bacterial foodborne illness in the European Union and the United States. Infection with Campylobacter spp. is frequently associated with different sequelae including neuropathies and reactive arthritis. Diagnosis is mainly by bacterial culturing which is time consuming, expensive, and not well suited for diagnosing sequelae or identifying infections from stool samples with nonviable bacteria. Serologic assays, in particular ELISAs, are well suited for this purpose, but, at present, there is no international consensus on antibody assays for human campylobacteriosis. In an extensive literature review, 19 studies validating such assays were identified of which 13 were more than 10 years old. We conclude that the best validated of these assays are developed and used in-house for research purposes rather than for routine diagnostics. Considering the burden of disease and potential long-term severity of Campylobacter infections, developing a standardized, commercially available antibody assay could be of great benefit for diagnostic and surveillance purposes worldwide.

Market surveillance for contamination with thermotolerant campylobacters on various categories of chicken meat in Switzerland

From April 2009 to April 2010, 1,132 samples of different types of chicken meat were tested qualitatively and quantitatively for thermotolerant campylobacters. Samples were recovered at retail in shops from the entire territory of Switzerland and comprised imported meat and meat from domestic production. The meat categories covered by the study were refrigerated and frozen meat, meat with and without skin, and meat preparations. Overall, 38.4% of the samples were positive, and in 27.8%, Campylobacter bacteria could be quantified. Counts ranged from ≥10 to <10(4) CFU/g with a maximum value of 8 × 10(3) CFU/g in a sample of refrigerated chicken meat with skin. The contamination frequencies were 45.2% in meat with skin, 40.8% in meat without skin, and 27.4% in meat preparations. Refrigerated meat was contaminated with Campylobacter bacteria more often than frozen meat (53.9 versus 20.0%). The study also showed considerable differences between the contamination rates found for samples from different large retail chains. In 2010, a further study with 120 samples of refrigerated and sliced chicken meat and fresh chicken liver was carried out in order to test a possible seasonal variation of the occurrence of Campylobacter bacteria. The contamination frequency of sliced meat increased from 10.0% in the period from February to March to 36.7% during July to August. In both sampling periods, the counts remained in the range of ≥10 to <100 CFU/g with a maximum value of 30 CFU/g. For chicken liver, a 10.0% contamination rate was observed in the period from December to January, which rose to 100% in the period from August to October. Contrary to the results for sliced meat, not only did the frequency of contamination increase but so did the Campylobacter counts, with the highest recorded value being 2.2 × 10(4) CFU/g.

The clinical importance of emerging Campylobacter species

A growing number of Campylobacter species other than C. jejuni and C. coli have been recognized as emerging human and animal pathogens. Although C. jejuni continues to be the leading cause of bacterial gastroenteritis in humans worldwide, advances in molecular biology and development of innovative culture methodologies have led to the detection and isolation of a range of under-recognized and nutritionally fastidious Campylobacter spp., including C. concisus, C. upsaliensis and C. ureolyticus. These emerging Campylobacter spp. have been associated with a range of gastrointestinal diseases, particularly gastroenteritis, IBD and periodontitis. In some instances, infection of the gastrointestinal tract by these bacteria can progress to life-threatening extragastrointestinal diseases. Studies have shown that several emerging Campylobacter spp. have the ability to attach to and invade human intestinal epithelial cells and macrophages, damage intestinal barrier integrity, secrete toxins and strategically evade host immune responses. Members of the Campylobacter genus naturally colonize a wide range of hosts (including pets, farm animals and wild animals) and are frequently found in contaminated food products, which indicates that these bacteria are at risk of zoonotic transmission to humans. This Review presents the latest information on the role and clinical importance of emerging Campylobacter spp. in gastrointestinal health and disease.