Five centuries of genome evolution and multi-host adaptation of Campylobacter jejuni in Brazil

Consumption of raw, undercooked or contaminated animal food products is a frequent cause of Campylobacter jejuni infection. Brazil is the world's third largest producer and a major exporter of chicken meat, yet population-level genomic investigations of C. jejuni in the country remain scarce. Analysis of 221 C. jejuni genomes from Brazil shows that the overall core and accessory genomic features of C. jejuni are influenced by the identity of the human or animal source. Of the 60 sequence types detected, ST353 is the most prevalent and consists of samples from chicken and human sources. Notably, we identified the presence of diverse bla genes from the OXA-61 and OXA-184 families that confer beta-lactam resistance as well as the operon cmeABCR related to multidrug efflux pump, which contributes to resistance against tetracyclines, macrolides and quinolones. Based on limited data, we estimated the most recent common ancestor of ST353 to the late 1500s, coinciding with the time the Portuguese first arrived in Brazil and introduced domesticated chickens into the country. We identified at least two instances of ancestral chicken-to-human infections in ST353. The evolution of C. jejuni in Brazil was driven by the confluence of clinically relevant genetic elements, multi-host adaptation and clonal population growth that coincided with major socio-economic changes in poultry farming.

Genomic characterisation of Campylobacter jejuni Cj26: A high-level ciprofloxacin/erythromycin-resistant strain isolated from a poultry carcass in southern Brazil

OBJECTIVES

The draft genome sequence of Campylobacter jejuni (Cj26) was analysed to investigate genetic mechanisms of antimicrobial resistance, virulence-associated genes, and phylogenetic context.

METHODS

Antimicrobial resistance was assessed by agar dilution and disk diffusion. Cj26 was sequenced using NovaSeq 6000 technology. The genome was assembled and annotated. Resistance genes and chromosomal mutations were analysed using the Center for Genomic Epidemiology services, and the multilocus sequence type, SVR-flaA, and porA were determined. The virulome was determined using the Virulence Factor Database. Plasmid detection and assembly were performed using Unicycler v0.5.0 software. To infer the core genome phylogeny, prokka v1.14.5 was employed in conjunction with IQtree v2.0.3.

RESULTS

The Cj26 strain showed a high level of resistance to ciprofloxacin (32 µg/mL) and erythromycin (>128 µg/mL) and resistance to tetracycline and ampicillin. Multilocus sequence typing revealed that the strain belonged to sequence type 353. The substitutions Tre-86-Ile in gyrA and A2075G in 23s RNA were detected, along with the genes tetO, aph(3')-III, ant(6)-Ia, and blaOXA 460. A consistent relationship among accessory and core genes was identified. When compared to other sequence type 353 genomes from Brazil, Cj26 clustered with strains that had more antimicrobial resistance genes than the other clusters.

CONCLUSION

This report provides insight into the antimicrobial resistance determinants found in a C. jejuni strain and offers a valuable resource for further studies on Campylobacter genomics and antimicrobial resistance.

Genomic and Antimicrobial Surveillance of Campylobacter Population in Italian Poultry

Campylobacter is one of the most common foodborne diseases worldwide with increasing rates of antibiotic resistance. Most cases of campylobacteriosis can be traced back to the consumption of poultry meat. Despite many efforts to reduce contamination in farms and in slaughterhouses, the persistence of this pathogen in poultry products remains a problem. This study aimed to evaluate the genetic diversity and antibiotic resistance of 542 C. jejuni and C. coli in Italian poultry, in the framework of two National Monitoring Programs. Genomes were screened for antibiotic resistance, virulence determinants and contextualized within a global collection of C. jejuni. ST2116, ST2863 and ST 832 were the most prevalent and significantly associated with Italian poultry. A worrying increase in resistance to quinolones, fluoroquinolones and tetracycline was observed in C. jejuni, while an increased occurrence of multidrug resistant (MDR) strains and strains resistant to macrolides was detected in C. coli. Low resistance rates were found for aminoglycosides. Molecular resistance determinants were consistent with the phenotypic resistance for tetracycline and quinolones. In silico analysis revealed 119 genes associated with virulence factors, with a notably higher prevalence of some genes in ST2863 genomes. This study highlights the increased resistance to macrolides and the emergence of MDR strains for C. coli, the genetic basis of AMR and the predominance of two genotypes among Campylobacter strains isolated from the Italian poultry farms.

Antimicrobial Resistance of Campylobacter coli Isolated from Caecal Samples of Fattening Pigs at Slaughter

Pigs are known as the main Campylobacter coli reservoirs. Campylobacteriosis, the most commonly reported gastrointestinal disease in humans, is mainly caused by the consumption of poultry meat, and little is known about the role of pork. Pigs are often associated with C. coli, including antimicrobial-resistant isolates. Therefore, the entire pork production chain must be considered as an important source of antimicrobial-resistant C. coli. This study aimed to determine the antimicrobial resistance of Campylobacter spp. isolated from caecal samples of fattening pigs at the Estonian slaughterhouse level over a five-year period. The proportion of Campylobacter-positive caecal samples was 52%. All Campylobacter isolates were identified as C. coli. A high proportion of the isolates were resistant to most of the studied antimicrobials. The resistance to streptomycin, tetracycline, ciprofloxacin and nalidixic acid was 74.8%, 54.4%, 34.4% and 31.9%, respectively. In addition, a high proportion (15.1%) of the isolates were multidrug-resistant and, in total, 93.3% were resistant to at least one antimicrobial.

Genomic Characterization of Antibiotic-Resistant Campylobacterales Isolated from Chilean Poultry Meat

Due to the lack of knowledge about Campylobacterales in the Chilean poultry industry, the objective of this research was to know the prevalence, resistance, and genotypes of Campylobacter, Arcobacter and Helicobacter in 382 samples of chicken meat purchased in Valdivia, Chile. The samples were analyzed using three isolation protocols. Resistance to four antibiotics was evaluated by phenotypic methods. Genomic analyses were performed on selected resistant strains to detect resistance determinants and their genotypes. A total of 59.2% of the samples were positive. Arcobacter butzleri (37.4%) was the most prevalent species, followed by Campylobacter jejuni (19.6%), C. coli (11.3%), A. cryaerophilus (3.7%) and A. skirrowii (1.3%). Helicobacter pullorum (14%) was detected by PCR in a subset of samples. Campylobacter jejuni was resistant to ciprofloxacin (37.3%) and tetracycline (20%), while C. coli and A. butzleri were resistant to ciprofloxacin (55.8% and 2.8%), erythromycin (16.3% and 0.7%) and tetracycline (4.7% and 2.8%), respectively. Molecular determinants were consistent with phenotypic resistance. The genotypes of C. jejuni (CC-21, CC-48, CC-49, CC-257, CC-353, CC-443, CC-446 and CC-658) and C. coli (CC-828) coincided with genotypes of Chilean clinical strains. These findings suggest that besides C. jejuni and C. coli, chicken meat could play a role in the transmission of other pathogenic and antibiotic-resistant Campylobacterales.

MLST genotypes and quinolone resistance profiles of Campylobacter jejuni isolates from various sources in Turkey

This study was conducted to determine the overall genetic diversity, as well as prevalence and mechanisms of resistance to quinolone antibiotics of 178 Campylobacter jejuni isolated from humans, cattle, dogs, and chickens in Turkey. Multilocus sequence typing (MLST) and E-test were performed for genotyping and antimicrobial susceptibility testing, respectively. Mismatch Amplification Mutation Assay, Polymerase Chain Reaction (MAMA-PCR) was used to detect point mutations associated with quinolone resistance. Of the 178 isolates tested, 151 were included in 21 clonal complexes (CCs); the remaining 27 isolates did not belong to any existing CCs. CC21, CC353, CC206, and CC257 were the predominant clones, representing 38 % of all C. jejuni isolates tested. The isolates were assigned to 78 different sequence types (STs), three of which were novel (ST 8082, ST 8083, and ST 8084). Resistance to quinolones was found in 73 (41 %) of the isolates (42.85 %, 2.85 %, 20.58 %, and 43.75 % in human, cattle, dog, and chicken isolates, respectively). All of the resistant isolates had Thr-86-Ile mutation in the gyrA gene. The highest Sorensen coefficient index was detected for human/chicken meat and human/dog C. jejuni isolates (Ss = 0.71), suggesting a strong link between the isolates from respective sources. The Simpson diversity index of C. jejuni isolates analyzed was detected between 0.92 and 0.98. The study provides detailed information on the quinolone resistance and MLST-based genetic relatedness of C. jejuni isolates from humans, cattle, dog, and broiler meat in Turkey for the first time, enabling a better understanding of the transmission pathways of C. jejuni in this country. Our results suggest that broiler meat and dogs may be the most important sources of human campylobacteriosis in Turkey.

Metagenomic Strain-Typing Combined with Isolate Sequencing Provides Increased Resolution of the Genetic Diversity of Campylobacter jejuni Carriage in Wild Birds

As the world's leading cause of human gastro-enteritis, the food- and waterborne pathogen Campylobacter needs to be intensively monitored through a One Health approach. Particularly, wild birds have been hypothesized to contribute to the spread of human clinical recurring C. jejuni genotypes across several countries. A major concern in studying epidemiological dynamics is resolving the large genomic diversity of strains circulating in the environment and various reservoirs, challenging to achieve with isolation techniques. Here, we applied a passive-filtration method to obtain isolates and in parallel recovered genotypes from metagenomic sequencing data from associated filter sweeps. For genotyping mixed strains, a reference-based computational workflow to predict allelic profiles of nine extended-MLST loci was utilized. We validated the pipeline by sequencing artificial mixtures of C. jejuni strains and observed the highest prediction accuracy when including obtained isolates as references. By analyzing metagenomic samples, we were able to detect over 20% additional genetic diversity and observed an over 50% increase in the potential to connect genotypes across wild-bird samples. With an optimized filtration method and a computational approach for genotyping strain mixtures, we provide the foundation for future studies assessing C. jejuni diversity in environmental and clinical settings at improved throughput and resolution.

Emerging patterns of fluoroquinolone resistance in Campylobacter jejuni in the UK [1998-2018]

Campylobacter jejuni (C.jejuni) is the most common causative agent of bacterial food poisoning worldwide and is known to be genetically highly diverse. C. jejuni is increasingly resistant to fluoroquinolone antibiotics, but very few studies have investigated variant-specific patterns of resistance across time. Here we use statistical modelling and clustering techniques to investigate patterns of fluoroquinolone resistance amongst 10,359 UK isolates from human disease sampled over 20 years. We observed six distinct patterns of fluoroquinolone sensitivity/resistance in C. jejuni across time, grouping by clonal complex (CC). Some CCs were fully resistant, some shifted from susceptible to resistant following a sigmoidal shape, and some remained susceptible over time. Our findings indicate that the fluoroquinolone resistance patterns of C. jejuni are complicated and cannot be analysed as a single species but divided into variant dynamics so that the factors driving resistance can be thoroughly investigated.

Correlation between Multilocus Sequence Typing and Antibiotic Resistance, Virulence Potential of Campylobacter jejuni Isolates from Poultry Meat

Campylobacter jejuni is a major foodborne pathogen and can be transmitted to human beings via the consumption of poultry products. This study aimed to determine antibiotic resistance and virulence potential of one hundred C. jejuni isolates from poultry meat and to explore the correlation between them and the multilocus sequence types (MLST). A total of 29 STs and 13 CCs were identified by MLST, of which 8 STs were first identified. The dominant ST was ST583 (21%), followed by ST42 (15%), ST61 (12%), and ST2276 (10%). Eighty-eight isolates showed resistance to at least one antibiotic. The resistance rate to fluoroquinolones was the highest (81%), followed by tetracycline (59%), whereas all the isolates were susceptible to erythromycin and telithromycin. Multi-antibiotic resistance was detected in 18 C. jejuni isolates. Great variability in the adhesion and invasion ability to Caco-2 cells was observed for the 100 isolates, with adhesion rates varying between 0.02% and 28.48%, and invasion rates varied from 0 to 6.26%. A correlation between STs and antibiotic resistance or virulence was observed. The ST61 isolates were significantly sensitive to CIP, while the TET resistance was significantly associated with ST354 and ST6175 complex. ST11326 showed substantially higher resistance to gentamicin and higher adhesion and invasion abilities to Caco-2 cells. The results helped improve our understanding of the potential hazard of different genotypes C. jejuni and provided critical information for the risk assessment of campylobacteriosis infection.

The Prevalence, Counts and MLST Genotypes of Campylobacter in Poultry Meat and Genomic Comparison with Clinical Isolates

Since 2005 campylobacteriosis has been the most commonly reported gastrointestinal infection in humans in the European Union with more than 200,000 cases annually. Also Campylobacter is one of the most frequent cause of food-borne outbreaks with 319 outbreaks reported to EFSA, involving 1,254 cases of disease and 125 hospitalizations in EU in 2019. Importantly poultry meat is one of the most common source for the sporadic Campylobacter infections and for strong-evidence campylobacteriosis food-borne outbreaks in EU.

 In present study, 429 fresh broiler chicken meat samples of Estonian, Latvian, and Lithuanian origin were collected from Estonian retail level and analyzed on a monthly basis between September 2018 and October 2019. Campylobacter spp. were isolated in 141 (32.9%) of 429 broiler chicken meat samples. Altogether 3 (1.8%), 49 (36.8%), and 89 (66.9%) of Estonian, Latvian, and Lithuanian origin broiler chicken meat samples were positive for Campylobacter spp. Among Campylobacter-positive samples, 62 (14.5%) contained Campylobacter spp. below 100 CFU/g and in 28 (6.5%) samples the count of Campylobacter spp. exceeded 1,000 CFU/g. A high prevalence of Campylobacter spp. in fresh broiler chicken meat of Lithuanian and Latvian origin in Estonian retail was observed. Additionally, 22 different multilocus sequence types were identified among 55 genotyped isolates of broiler chicken meat and human origin, of which 45 were Campylobacter jejuni (C. jejuni) and 10 were Campylobacter coli (C. coli). The most prevalent multilocus sequence types among C. jejuni was ST2229 and among C. coli ST832, ST872. C. jejuni genotypes found in both broiler chicken meat and human origin samples were ST122, ST464, ST7355, and ST9882, which indicates that imported fresh broiler chicken meat is likely the cause of human campylobacteriosis in Estonia.

Prevalence of antimicrobial resistance in Campylobacter spp.: A review of the literature

Campylobacter spp. are commensal organisms in the intestinal tract of food producing and companion animals. There is an increasing trend of human campylobacteriosis worldwide, including complicated cases that request treatment by antibiotics. Prevalence of resistance continually increases, especially to fluoroquinolones and tetracyclines. There are many reports on multiresistant strains of Campylobacter spp.In this work we present the available information about the prevalence and antimicrobial resistance of Campylobacter spp. worldwide, as well as studies from Serbia published in last two decades. Campylobacter strains isolated from animal samples in Serbia showed increased prevalence of antimicrobial resistance to all clinically relevant antibiotics. Preliminary data (2014-2019) from Reference laboratory for Campylobacter and Helicobacter at the Institute of Public Health of Niš, Serbia show high resistance rates to ciprofloxacin (90%) and to tetracycline (50%) but low resistance to erythromycin (<5%) in human Campylobacter isolates.

Genomic analysis of extra-intestinal Campylobacter jejuni and Campylobacter coli isolated from commercial chickens

Campylobacter jejuni and Campylobacter coli have commonly been considered harmless commensal inhabitants of the chicken gut; however, these Campylobacter spp. are known to be able to multiply in the gut and invade other tissues, negatively affecting host health and performance. In this study, fourteen Campylobacter spp. were isolated from chickens showing foci of necrosis on the liver surface resembling lesions observed in cases of avian vibrionic hepatitis/spotty liver disease. The whole genome sequences of the fourteen isolates were analysed and their virulomes compared to those of Campylobacter reference sequences, aiming to investigate the possible association between virulence genes and the observed pathological lesions. Nine C. jejuni and five C. coli were studied. These Campylobacter shared twelve virulence factors with other isolates originated from chicken livers and hosted a higher number of virulence-associated genes in comparison to the reference genomes, including genes encoding for factors involved in adherence to and invasion of the intestinal epithelial cells. Our findings seem to point out that these twelve common virulence-associated genes, together with the presence of a high number of virulence factors involved in adherence, invasion and motility, might be responsible for the extra-intestinal spread of our isolates and the colonization of parenchymatous tissues, possibly causing the pathological lesions observed.

Prevalence and antimicrobial susceptibility of Campylobacter isolated from retail chickens in Thailand

Campylobacter is an important foodborne pathogen causing bacterial gastroenteritis worldwide; however, there has been a lack of information over the past decade on its occurrence, antibiotic susceptibility and genetic diversity in Thailand. Poultry meat is considered as a reservoir for transmission of Campylobacter to humans. This study determines the prevalence and antimicrobial resistance patterns of Campylobacter spp. on chicken samples purchased from 50 local wet markets and supermarkets in central Thailand. Of the 296 samples, 99 (33.5%) were contaminated with C. jejuni, 54 (18.2%) were C. coli and 15 (5.1%) were contaminated with both species. Antibiotic resistance rate is higher among C. coli isolates; 100%, 76.8%, 37.7%, 36.2% and 13.0% were resistant to quinolones, cyclines, macrolides, clindamycin and gentamicin, respectively. Most of the C. jejuni isolates were resistant to quinolones (79.8%) and cyclines (38.6%) whereas resistance to macrolides, clindamycin and gentamicin was found to be 1.8%. Multi-drug resistance (i.e. to three or more unrelated antimicrobials) was detected in 37.7% of C. coli and 1.8% of C. jejuni isolates. This study has revealed high contamination rates and alarming levels of antimicrobial resistance in Campylobacter spp. isolated from retail chicken samples in Thailand, suggesting the necessity of implementing interventions to reduce its prevalence from farm to table in the country.

Effects of Lactobacillus Fermentum Supplementation on Body Weight and Pro-Inflammatory Cytokine Expression in Campylobacter Jejuni-Challenged Chickens

Due to the interest in using probiotic bacteria in poultry production, this research was focused on evaluating the effects of Lactobacillus fermentum Biocenol CCM 7514 administration on body weight gain and cytokine gene expression in chickens challenged with Campylobacter jejuni. One-hundred and eight 1-day old COBB 500 broiler chickens were equally assigned to four experimental groups at random. In the control group (C) chicks were left untreated, whereas in groups LB and LBCj a suspension of L. fermentum was administered. A suspension of C. jejuni was subsequently applied to groups Cj and LBCj. Body weight was registered, and the individuals were later slaughtered; cecum samples were collected at 12, 36 and 48 h post-infection (hpi). The entire experiment lasted seven days. Reverse transcription quantitative PCR (RT-qPCR) was used to determine expression levels of IL-1β, IL-15, IL-17, and IL-18 at each time point. Pathogen-infected individuals were observed to weigh significantly less than those fed with the probiotic. Significant differences were also found in transcript abundance; expression of IL-15 was downregulated by the probiotic and upregulated by C. jejuni. The effects of bacterial treatments were time-dependent, as the expression profiles differed at later stages. The present outcomes demonstrate that L. fermentum both reduces the impact of C. jejuni infection on chicken body weight and regulates positively pro-inflammatory cytokine expression, which ultimately increase bird well-being and improves production.

The source attribution analysis revealed the prevalent role of poultry over cattle and wild birds in human campylobacteriosis cases in the Baltic States

The reservoir and source of human campylobacteriosis is primarily considered to be poultry, but also other such as ruminants, pets and environmental sources are related with infection burden. Multilocus sequence typing is often used for Campylobacter epidemiological studies to determine potential sources of human infections. The collection of 420 Campylobacter jejuni isolates with assigned MLST genotype from poultry (n = 139), cattle (n = 48) and wild birds (n = 101) were used in source attribution analysis. Asymmetric island model with accurate and congruent self-attribution results, was used to determine potential sources of human C. jejuni infections (n = 132) in Baltic States. Source attribution analysis revealed that poultry (88.3%) is the main source of C. jejuni human infections followed by cattle and wild bird with 9.4% and 2.3%, respectively. Our findings demonstrated that clinical cases of C. jejuni infections in Baltic countries are mainly linked to poultry, but also to cattle and wild bird sources.

Antimicrobial Resistance Determinants Circulating among Thermophilic Campylobacter Isolates Recovered from Broilers in Ireland Over a One-Year Period

Campylobacteriosis is the leading cause of human bacterial gastroenteritis, very often associated with poultry consumption. Thermophilic Campylobacter (Campylobacter jejuni and Campylobacter coli) isolates (n = 158) recovered from broiler neck skin and caecal contents in Ireland over a one-year period, resistant to at least one of three clinically relevant antimicrobial classes, were screened for resistance determinants. All ciprofloxacin-resistant isolates (n = 99) harboured the C257T nucleotide mutation (conferring the Thr-86-Ile substitution) in conjunction with other synonymous and nonsynonymous mutations, which may have epidemiological value. The A2075G nucleotide mutation and amino acid substitutions in L4 and L22 were detected in all erythromycin-resistant isolates (n = 5). The tetO gene was detected in 100% (n = 119) of tetracycline-resistant isolates and three of which were found to harbour the mosaic tetracycline resistance gene tetO/32/O. Two streptomycin-resistant C. jejuni isolates (isolated from the same flock) harboured ant(6)-Ib, located in a multidrug resistance genomic island, containing aminoglycoside, streptothricin (satA) and tetracycline resistance genes (truncated tetO and mosaic tetO/32/O). The ant(6)-Ie gene was identified in two streptomycin-resistant C. coli isolates. This study highlights the widespread acquisition of antimicrobial resistance determinants among chicken-associated Campylobacter isolates, through horizontal gene transfer or clonal expansion of resistant lineages. The stability of such resistance determinants is compounded by the fluidity of mobile genetic element.

Strategies and novel technologies to control Campylobacter in the poultry chain: A review

Campylobacteriosis is one of the most common bacterial infections worldwide causing economic costs. The high prevalence of Campylobacter spp. in poultry meat is a result of several contamination and cross-contamination sources through the production chain. Moreover, survival mechanisms, such as biofilm formation, viable but nonculturable state, and antimicrobial resistance, enable its persistence during food processing. Therefore, mitigation strategies are necessary in order to avoid and/or inactivate Campylobacter at farm, abattoir, industry, and retail level. In this review, a number of potential strategies and novel technologies that could reduce the prevalence of Campylobacter in poultry meat have been identified and evaluated to provide a useful overview. At farm level for instance, biosecurity, bacteriocins, probiotics, feed and water additives, bacteriophages, and vaccination could potentially reduce colonization in chicken flocks. However, current technologies used in the chicken slaughter and processing industry may be less effective against this foodborne pathogen. Novel technologies and strategies such as cold plasma, ultraviolet light, high-intensity light pulses, pulsed electric fields, antimicrobials, and modified atmosphere packaging are discussed in this review for reducing Campylobacter contamination. Although these measures have achieved promising results, most have not been integrated within processing operations due to a lack of knowledge or an unwillingness to implement these into existing processing systems. Furthermore, a combination of existing and novel strategies might be required to decrease the prevalence of this pathogen in poultry meat and enhance food safety. Therefore, further research will be essential to assess the effectiveness of all these strategies.

Campylobacter species prevalence, characterisation of antimicrobial resistance and analysis of whole-genome sequence of isolates from livestock and humans, Latvia, 2008 to 2016

BackgroundCampylobacter is the main cause of bacterial gastroenteritis worldwide. The main transmission route is through consumption of food contaminated with Campylobacter species or contact with infected animals. In Latvia, the prevalence of campylobacteriosis is reported to be low (4.6 cases per 100,000 population in 2016).AimTo determine prevalence, species spectrum and antimicrobial resistance (AMR) of Campylobacter spp. in Latvia, using data from various livestock and human clinical samples.MethodsWe analysed data of Campylobacter microbiological monitoring and AMR (2008 and 2014-16) in Latvia. Data from broilers, poultry, pigs, calves and humans were used to determine prevalence of Campylobacter. Additionally, 45 different origin isolates (22 human) were sequenced on the Illumina MiSeq platform; for each isolate core genome multilocus sequence typing was used and relevant antimicrobial resistance mechanisms were identified.ResultsOverall, Campylobacter prevalence in was 83.3% in pigs, 50.2% in broilers, 16.1% in calves and 5.3% in humans; C. jejuni was the predominant species in all sources except pigs where C. coli was main species. High level of resistance in Campylobacter were observed against fluoroquinolones, tetracycline and streptomycin, in most of sequenced isolates genetic determinants of relevant AMR profiles were identified.ConclusionsIn Latvia, prevalence of Campylobacter in livestock is high, especially in pigs and broilers; prevalence in poultry and humans were lower than in other European countries. AMR analysis reveals increase of streptomycin and tetracycline resistant broiler origin C. jejuni strains. WGS demonstrates a high compliance between resistance phenotype and genotype for quinolones and tetracyclines.

Whole-genome multilocus sequence typing of closely related broiler chicken meat origin Campylobacter jejuni ST-5 isolates

Broiler chicken meat is considered as the main source of foodborne Campylobacter infection. Campylobacter jejuni multilocus sequence type ST-5 has been previously identified as predominant among Latvian and Lithuanian broiler chicken meat products and is often isolated from Lithuanian patients with Campylobacter enteric infection. The market share of Lithuanian and Latvian origin fresh broiler chicken meat sold at Estonian retail is estimated close to 50%. In this study, we used the whole-genome sequences of Latvian and Lithuanian origin C. jejuni ST-5 broiler chicken meat isolates obtained from Estonian retail. Applied genome-by-genome whole-genome MLST revealed high similarity of investigated isolates with 1589 shared alleles, of which 218 loci were polymorphic. Latvian and Lithuanian isolates had 199 to 205 intergroup differences in shared alleles, whereas intragroup isolates differed by 27 to 31 alleles. Allele differences divided the isolates into 2 distinct groups based on the country of origin, which was supported by sequence-based phylogenetic tree. The resulting geographic separation of the isolates found in this study should be carefully interpreted taking into account the small sample size.

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.