Genotypes and antibiotic resistance of bovine Campylobacter and their contribution to human campylobacteriosis

Comparative Analysis of Campylobacter jejuni and C. coli Isolated from Livestock Animals to C. jejuni and C. coli Isolated from Surface Water Using DNA Sequencing and MALDI-TOF

This study evaluated the contribution of cattle, sheep, poultry and pigs to the contamination of surface water from rivers by Campylobacter jejuni and C. coli using MLST, cgMLST and considered MALDI-TOF MS as an alternative technique. The 263 strains isolated from cattle (n = 61), sheep (n = 42), poultry (n = 65), pigs (n = 60) and surface water (n = 35) were distributed across 115 sequence types (STs), 49 for C. jejuni and 66 for C. coli. Considering MLST data, 14.2%, 11.4% and 2.8% of the surface water strains could be attributed to cattle, poultry and sheep, respectively, none to pigs, and 85.7% were non-attributed. Analysis of cg-MLST data with STRUCTURE indicated that C. jejuni strains from water were predominantly attributed to poultry (93.5%), weakly to sheep (<1%) and 6.3% non-attributed, and that conversely, C. coli strains from water were predominantly non-attributed (94.3%) and 5.7% attributed to poultry. Considering the protein profiles with a threshold of 94% and 97% of similarity, respectively, strains from surface water could be attributed to poultry (31.4% and 17.1%), and to cattle (17.1% and 5.7%); 54.1% and 77.1% were non-attributed. This study confirmed these livestock animals might contribute to the contamination of surface water, with a level of contribution depending on the typing technique and the method of analysis. MALDI-TOF could potentially be an alternative approach for source attribution.

Prevalence and fluoroquinolone resistance of Campylobacter spp. isolated from beef cattle in Japan

Beef is a source of human Campylobacter infections. Antimicrobial treatment is needed when patients are immunocompromised or have other comorbidities. Therefore, we investigated the prevalence and antimicrobial resistance of Campylobacter spp. in beef cattle in Japan. Rectal swab samples were collected from 164 beef cattle at an abattoir between March 2021 and August 2021, and Campylobacter spp. were isolated from 94 (57.3%) cattle. C. jejuni and C. coli were isolated from 68 and 26 cattle, respectively. For Campylobacter jejuni, the resistant rates against ampicillin, tetracycline and ciprofloxacin were 20.6, 75.0 and 64.7%, respectively. For C. coli, the resistant rates against ampicillin, tetracycline and ciprofloxacin were 53.8, 76.9 and 88.5%, respectively. No Campylobacter isolates were resistant to erythromycin. By multilocus sequence typing, C. jejuni and C. coli isolates were classified into 22 and 2 sequence types (STs). The top three STs of C. jejuni were ST806 (12 isolates), ST21 (nine isolates), and ST459 (eight isolates). The most frequent ST of C. coli was ST1068 (23 isolates). The results suggest that Campylobacter spp. are prevalent in the gastrointestinal tract of beef cattle slaughtered at abattoirs. Furthermore, the administration of erythromycin is effective against human campylobacteriosis caused by beef consumption. Monitoring the prevalence and antimicrobial resistance of Campylobacter spp. in beef cattle could be useful for managing the risk of human campylobacteriosis.

Comparative macrolide use in humans and animals: should macrolides be moved off the World Health Organisation's critically important antimicrobial list?

Macrolide antibiotics are categorized by the WHO as Highest Priority, Critically Important Antimicrobials due to their recommendation as treatment for severe cases of campylobacteriosis in humans; a self-limiting, rarely life-threatening, zoonotic foodborne infection. Low rates of macrolide resistance in Campylobacter jejuni and the availability of alternative treatments have prompted some regulatory schemes to assign macrolides to a lower importance category. Apart from rare, specific infections, macrolides largely play a supportive role to other drug classes in human medicine. By contrast, although the advent of alternative control methods has seen significant reductions in macrolide use in intensive livestock, they still have a crucial role in the treatment/control of respiratory infections and liver abscesses in cattle. Whilst acknowledging that ongoing surveillance is required to reduce the spread of recently emerged, transferable macrolide resistance among Campylobacter, this article recommends that macrolides should be moved to the WHO Highly Important category.

The Data Behind Risk Analysis of Campylobacter Jejuni and Campylobacter Coli Infections

Campylobacter jejuni and Campylobacter coli are major causes of food-borne enteritis in humans. Poultry meat is known to be responsible for a large proportion of cases of human campylobacteriosis. However, other food-borne, environmental and animal sources are frequently associated with the disease in humans as well. Human campylobacteriosis causes gastroenteritis that in most cases is self-limiting. Nevertheless, the burden of the disease is relatively large compared with other food-borne diseases, which is mostly due to rare but long-lasting symptoms related to immunological sequelae. In order to pave the way to improved surveillance and control of human campylobacteriosis, we review here the data that is typically used for risk analysis to quantify the risk and disease burden, identify specific surveillance strategies and assist in choosing the most effective control strategies. Such data are mostly collected from the literature, and their nature is discussed here, for each of the three processes that are essential for a complete risk analysis procedure: risk assessment, risk management and risk communication. Of these, the first, risk assessment, is most dependent on data, and this process is subdivided into the steps of hazard identification, hazard characterization, exposure assessment and risk characterization. For each of these steps of risk assessment, information from published material that is typically collected will be summarized here. In addition, surveillance data are highly valuable for risk assessments. Different surveillance systems are employed in different countries, which can make international comparison of data challenging. Risk analysis typically results in targeted control strategies, and these again differ between countries. The applied control strategies are as yet not sufficient to eradicate human campylobacteriosis. The surveillance tools of Campylobacter in humans and exposure sources in place in different countries are briefly reviewed to better understand the Campylobacter dynamics and guide control strategies. Finally, the available control measures on different risk factors and exposure sources are presented.

Assessing Campylobacter Colonization of Broiler Herds Ante Mortem and Monitoring Campylobacter Contamination Post Mortem by qPCR

Human campylobacteriosis is the most prevalent zoonosis, with chicken meat contributing substantially to the number of cases. Measures to avoid or at least reduce exposure by meat contaminated with Campylobacter (C.) spp. are needed. With regard to the process hygiene criterion introduced in 2018 for Campylobacter spp. on broiler carcasses, we evaluated the performance of a recently developed quantitative real-time PCR (qPCR) for C. jejuni/coli on random caecal samples and chicken meat. With the qPCR on pooled caecal samples not only C. jejuni/coli positive (69.6%) versus negative broiler herds (30.4%) were identified, but herds highly colonized with C. jejuni/coli (39.4%) could also be identified. From the chicken meat samples, 8.0% were positive for C. jejuni/coli by qPCR and 0.7% by enumeration (>10 cfu/g) compared to 58.3% using cultural enrichment. Given the higher sensitivity, the qPCR method could replace the currently used enumeration method to assess the process hygiene criterion for Campylobacter spp. on broiler carcasses. Moreover, with the qPCR, a reliable identification of C. jejuni/coli colonized incoming broiler herds a few days before slaughter is feasible, which provides important information to optimize slaughter processes. Finally, identifying and monitoring herds with high C. jejuni/coli colonization rates could help to individually improve biosecurity measures at farm level, eventually reducing the C. jejuni/coli load on chicken meat.

A systematic review of source attribution of human campylobacteriosis using multilocus sequence typing

BackgroundCampylobacter is a leading global cause of bacterial gastroenteritis, motivating research to identify sources of human infection. Population genetic studies have been increasingly applied to this end, mainly using multilocus sequence typing (MLST) data.ObjectivesThis review aimed to summarise approaches and findings of these studies and identify best practice lessons for this form of genomic epidemiology.MethodsWe systematically reviewed publications using MLST data to attribute human disease isolates to source. Publications were from January 2001, when this type of approach began. Searched databases included Scopus, Web of Science and PubMed. Information on samples and isolate datasets used, as well as MLST schemes and attribution algorithms employed, was obtained. Main findings were extracted, as well as any results' validation with subsequent correction for identified biases. Meta-analysis is not reported given high levels of heterogeneity.ResultsOf 2,109 studies retrieved worldwide, 25 were included, and poultry, specifically chickens, were identified as principal source of human infection. Ruminants (cattle or sheep) were consistently implicated in a substantial proportion of cases. Data sampling and analytical approaches varied, with five different attribution algorithms used. Validation such as self-attribution of isolates from known sources was reported in five publications. No publication reported adjustment for biases identified by validation.ConclusionsCommon gaps in validation and adjustment highlight opportunities to generate improved estimates in future genomic attribution studies. The consistency of chicken as the main source of human infection, across high income countries, and despite methodological variations, highlights the public health importance of this source.

Occurrence of Campylobacter jejuni and Campylobacter coli in Cattle and Sheep in Northern Spain and Changes in Antimicrobial Resistance in Two Studies 10-years Apart

A cross-sectional survey was conducted in 2014-2016 in 301 ruminant herds to estimate C. jejuni and C. coli prevalence, and investigate their susceptibility to antimicrobials. Risk of shedding C. jejuni was higher in cattle than sheep (81.2% vs. 45.2%; ORadj = 5.22, p < 0.001), whereas risk of shedding C. coli was higher in sheep than in cattle (19.1% vs. 11.3%; ORadj = 1.71, p = 0.128). Susceptibility to six antimicrobials was determined by broth microdilution using European Committee for Antimicrobial Susceptibility Testing (EUCAST) epidemiological cut-off values. C. coli exhibited higher resistance (94.1%, 32/34) than C. jejuni (65.1%, 71/109), and resistance was more widespread in isolates from dairy cattle than beef cattle or sheep. Compared to results obtained 10-years earlier (2003-2005) in a similar survey, an increase in fluoroquinolone-resistance was observed in C. jejuni from beef cattle (32.0% to 61.9%; OR = 3.45, p = 0.020), and a decrease in tetracycline-resistance in C. jejuni from dairy cattle (75.0% to 43.2%; OR = 0.25, p = 0.026). Resistance to macrolides remained stable at low rates and restricted to C. coli from dairy cattle, with all macrolide-resistant C. coli showing a pattern of pan-resistance. Presence of the single nucleotide polymorphisms (SNPs) associated to quinolone and macrolide resistance was confirmed in all phenotypically resistant isolates. The increase in fluoroquinolone resistance is worrisome but susceptibility to macrolides is reassuring.

Long-term observation of antimicrobial susceptibility and molecular characterisation of Campylobacter jejuni isolated in a Japanese general hospital 2000-2017

OBJECTIVES

Campylobacter jejuni (C. jejuni) is one of the most common pathogens that causes gastroenteritis. Because there is currently insufficient epidemiological information about the antimicrobial susceptibility and molecular characterisation of clinical isolates of C. jejuni in Japan, this study carried out antimicrobial susceptibility testing and multilocus sequence typing (MLST) of clinical C. jejuni isolates in Tokyo between 2000-2017.

METHODS

Antimicrobial susceptibility to erythromycin and ciprofloxacin was tested using the broth microdilution method in 430 C. jejuni clinical isolates collected over 18 years, between 2000-2017, at a Tokyo general hospital. To observe the sequence type (ST) evolution, 82 isolates were chosen from three non-consecutive years (16 isolates from 2000, 25 isolates from 2008, and 41 isolates from 2017) and analysed by MLST as a molecular characterisation test. Mutations in the quinolone resistance-determining region of the gyrA and gyrB genes were identified.

RESULTS

The rate of resistance to erythromycin was low, but that of ciprofloxacin resistance was 34.9% in 2000-2008 and 41.9% in 2009-2017. The most common clonal complex (CC) identified during the entire period was CC21; ST4526 with ciprofloxacin resistance was highly prevalent in 2017 (6 of 11; 54.5%).

CONCLUSION

The results indicate that the rate of resistance to quinolone has gradually increased. Since ST4526 was not isolated in 2000 and 2008, it is likely that ST4526 is rapidly increasing in Japan.

Antimicrobial Resistance and Genotypes of Campylobacter jejuni from Pig and Cattle Carcasses Isolated in Poland During 2009-2016

Between 2009 and 2016, 317 and 529 swabs from cattle and pig carcasses, respectively, were collected all over Poland and tested for the presence of Campylobacter. Among 37 (11.7%) and 161 (30.4%) positive samples, 44 Campylobacter jejuni isolates were detected. A total of 29 different sequence types (STs) and 12 various clonal complexes were identified. Antimicrobial resistance revealed that 17 (38.6%) C. jejuni (10 from cattle and 7 from pig carcasses, respectively) were susceptible to all antimicrobials used in the study, whereas the remaining 27 (61.4%) isolates (12 from cattle and 15 from pigs, respectively) were resistant to at least one antimicrobial agent, mainly to quinolones (23 out of 44 isolates; 52.3%) and tetracyclines (14 strains; 31.8%). Only one isolate from cattle and two from pigs displayed resistance to streptomycin, and none of C. jejuni tested was resistant to erythromycin and gentamicin. All isolates with STs, ST356, ST443, ST464, ST658, ST2036, and ST6411, as well as some isolates belonging to ST257 and ST1947, were resistant to quinolones and tetracyclines. The results show that cattle and pigs may be a reservoir of quinolone and tetracycline resistant C. jejuni with STs which were previously isolated from humans with campylobacteriosis.

A Quantitative Real-Time PCR Approach for Assessing Campylobacter jejuni and Campylobacter coli Colonization in Broiler Herds

Human campylobacteriosis is a major public health concern in developed countries, with Campylobacter jejuni and Campylobacter coli from poultry recognized as the main source of human infection. Identification of Campylobacter-positive broiler herds before slaughter is essential for implementing measures to avoid carryover of pathogens via the slaughter process into the food chain. However, appropriate methods that have been validated for testing poultry flocks antemortem are lacking for Campylobacter. A quantitative real-time PCR (qPCR) that allows simultaneous detection and quantification of C. jejuni and C. coli was adapted and optimized to be applied on boot socks. The adjusted qPCR serves as an easy, sensitive, and quantitative method for Campylobacter detection in poultry flocks antemortem by analysis of boot socks. An adequate correlation was found between qPCR and culture, as well as between boot socks and cecal samples, which are regarded as the "gold standard." Therefore, boot sock sampling followed by qPCR analysis provides a reliable and simple method for assessing Campylobacter load within a flock prior to slaughter. The approach allows categorization of broiler herds into negative, low, moderate, or high Campylobacter colonization. Based on the results of this new approach, risk assessment models, such as evaluating the possible effect of sorting flocks before slaughter, can be easily implemented. Similarly, targeted identification of highly colonized flocks for improvement of biosecurity measures at the farm level will become feasible, presenting an opportunity to increase food safety.

Antimicrobial usage and resistance in beef production

Antimicrobials are critical to contemporary high-intensity beef production. Many different antimicrobials are approved for beef cattle, and are used judiciously for animal welfare, and controversially, to promote growth and feed efficiency. Antimicrobial administration provides a powerful selective pressure that acts on the microbial community, selecting for resistance gene determinants and antimicrobial-resistant bacteria resident in the bovine flora. The bovine microbiota includes many harmless bacteria, but also opportunistic pathogens that may acquire and propagate resistance genes within the microbial community via horizontal gene transfer. Antimicrobial-resistant bovine pathogens can also complicate the prevention and treatment of infectious diseases in beef feedlots, threatening the efficiency of the beef production system. Likewise, the transmission of antimicrobial resistance genes to bovine-associated human pathogens is a potential public health concern. This review outlines current antimicrobial use practices pertaining to beef production, and explores the frequency of antimicrobial resistance in major bovine pathogens. The effect of antimicrobials on the composition of the bovine microbiota is examined, as are the effects on the beef production resistome. Antimicrobial resistance is further explored within the context of the wider beef production continuum, with emphasis on antimicrobial resistance genes in the food chain, and risk to the human population.

Human Campylobacteriosis in Luxembourg, 2010-2013: A Case-Control Study Combined with Multilocus Sequence Typing for Source Attribution and Risk Factor Analysis

Campylobacteriosis has increased markedly in Luxembourg during recent years. We sought to determine which Campylobacter genotypes infect humans, where they may originate from, and how they may infect humans. Multilocus sequence typing was performed on 1153 Campylobacter jejuni and 136 C. coli human strains to be attributed to three putative animal reservoirs (poultry, ruminants, pigs) and to environmental water using the asymmetric island model. A nationwide case-control study (2010-2013) for domestic campylobacteriosis was also conducted, including 367 C. jejuni and 48 C. coli cases, and 624 controls. Risk factors were investigated by Campylobacter species, and for strains attributed to different sources using a combined case-control and source attribution analysis. 282 sequence types (STs) were identified: ST-21, ST-48, ST-572, ST-50 and ST-257 were prevailing. Most cases were attributed to poultry (61.2%) and ruminants (33.3%). Consuming chicken outside the home was the dominant risk factor for both Campylobacter species. Newly identified risk factors included contact with garden soil for either species, and consuming beef specifically for C. coli. Poultry-associated campylobacteriosis was linked to poultry consumption in wintertime, and ruminant-associated campylobacteriosis to tap-water provider type. Besides confirming chicken as campylobacteriosis primary source, additional evidence was found for other reservoirs and transmission routes.

Multilocus Sequence Typing and Antimicrobial Resistance of Campylobacter jejuni Isolated from Dairy Calves in Austria

Human campylobacteriosis is primarily associated with poultry but also cattle. In this study, 55 Campylobacter jejuni strains isolated from 382 dairy calves’ feces were differentiated by multilocus sequence typing and tested for antimicrobial resistance. The most prevalent sequence type (ST) was ST883 (20.0%), followed by ST48 (14.5%), and ST50 (9.1%). In contrast to ST48 and ST50, ST883 has rarely been described in cattle previously. Furthermore, risk factor analysis was performed for the presence of the most prevalent STs in these calves. Multiple regression analysis revealed that the type of farm (organic vs. conventional) and calf housing (place, and individual vs. group) were identified as significantly (p < 0.05) associated with the presence of ST883 in calves, and ST50 was associated with calf diarrhea. Antimicrobial resistance was detected in 58.2% of the isolates. Most of the resistant isolates (81.3%) were resistant to more than one antimicrobial. Most frequently, resistance to ciprofloxacin (49.1%), followed by nalidixic acid (42.8%), and tetracycline (14.5%) was observed. The results of the present study support the hypothesis that dairy calves may serve as a potential reservoir for C. jejuni and pose a risk for transmission, including antimicrobial resistant isolates to the environment and to humans.

High genetic similarity of ciprofloxacin-resistant Campylobacter jejuni in central Europe

Campylobacteriosis is the leading zoonosis in the European Union with the majority of cases attributed to Campylobacter jejuni. Although the disease is usually self-limiting, some severe cases need to be treated with antibiotics, primarily macrolides and quinolones. However, the resistance to the latter is reaching alarming levels in most of the EU countries. To shed light on the expansion of antibiotic resistance in central Europe, we have investigated genetic similarity across 178 ciprofloxacin-resistant C. jejuni mostly isolated in Slovenia, Austria and Germany. We performed comparative genetic similarity analyses using allelic types of seven multilocus sequence typing housekeeping genes, and single nucleotide polymorphisms of a quinolone resistance determining region located within the DNA gyrase subunit A gene. This analysis revealed high genetic similarity of isolates from clonal complex ST-21 that carry gyrA allelic type 1 in all three of these central-European countries, suggesting these ciprofloxacin resistant isolates arose from a recent common ancestor and are spread clonally.

Regulation of oxidative stress resistance in Campylobacter jejuni, a microaerophilic foodborne pathogen

Campylobacter jejuni is one of the leading bacterial causes of human gastroenteritis. Due to the increasing rates of human campylobacteriosis, C. jejuni is considered as a serious public health concern worldwide. C. jejuni is a microaerophilic, fastidious bacterium. C. jejuni must overcome a wide range of stress conditions during foodborne transmission to humans, such as food preservation and processing conditions, and even in infection of the gastrointestinal tracts of humans. Particularly, this microaerophilic foodborne pathogen must survive in the atmospheric conditions prior to the initiation of infection. C. jejuni possesses unique regulatory mechanisms for oxidative stress resistance. Lacking OxyR and SoxRS that are highly conserved in other Gram-negative foodborne pathogens, C. jejuni modulates the expression of genes involved in oxidative stress resistance mainly via the peroxide resistance regulator and Campylobacter oxidative stress regulator. Based on recent findings of ours and others, in this review, we described how C. jejuni regulates the expression of oxidative stress defense.