A Decade of Antimicrobial Resistance in Human and Animal Campylobacter spp. Isolates

Objectives: Campylobacter spp. remain a leading cause of bacterial gastroenteritis worldwide, with resistance to antibiotics posing significant challenges to treatment and public health. This study examines profiles in antimicrobial resistance (AMR) for Campylobacter isolates from human and animal sources over the past decade. Methods: We conducted a comprehensive review of resistance data from studies spanning ten years, analyzing profiles in resistance to key antibiotics, ciprofloxacin (CIP), tetracycline (TET), erythromycin (ERY), chloramphenicol (CHL), and gentamicin (GEN). Data were collated from various regions to assess global and regional patterns of resistance. Results: The analysis reveals a concerning trend of increasing resistance patterns, particularly to CIP and TET, across multiple regions. While resistance to CHL and GEN remains relatively low, the high prevalence of CIP resistance has significantly compromised treatment options for campylobacteriosis. Discrepancies in resistance patterns were observed between human and animal isolates, with variations across different continents and countries. Notably, resistance to ERY and CHL showed regional variability, reflecting potential differences in antimicrobial usage and management practices. Conclusions: The findings underscore the ongoing challenge of AMR in Campylobacter, highlighting the need for continued surveillance and research. The rising resistance prevalence, coupled with discrepancies in resistance patterns between human and animal isolates, emphasize the importance of a One Health approach to address AMR. Enhanced monitoring, novel treatment strategies, and global cooperation are crucial for mitigating the impact of resistance and ensuring the effective management of Campylobacter-related infections.

Epidemiological Data and Antimicrobial Resistance of Campylobacter spp. in Portugal from 13 Years of Surveillance

This study extensively analyzed campylobacteriosis surveillance in Portugal from 2009 to 2021, aiming to investigate demographic shifts, seasonal variations, and antimicrobial resistance (AMR) within Campylobacter isolates. Surveillance network and sentinel laboratory-based system data revealed a substantial under-notification of campylobacteriosis cases, suggesting an underestimated disease burden. Notification rates exhibited a paradigm shift, with a notable prevalence among the pediatric population, particularly in children aged 1-4 years, diverging from European reports. Additionally, an emerging trend of Campylobacter infections in younger adults (15-44 years) was observed. The study unveiled a unique seasonal distribution of cases, defying typical summer peaks seen elsewhere. AMR analysis revealed high resistance to ciprofloxacin and tetracycline, in both C. jejuni (93.7% and 79.2%, respectively) and C. coli (96.5% and 93.2%, respectively), stable throughout the studied period (2013-2021). C. coli exhibited significantly higher resistance to erythromycin, gentamicin, ampicillin and ertapenem compared to C. jejuni (p < 0.001). Multilocus Sequence Typing (MLST) data demonstrated the distribution of resistance markers across diverse sequence types, challenging the notion of a clonal origin for multidrug-resistant isolates. In conclusion, the study highlights the need for enhanced surveillance and raises concerns about alarming AMR levels, recommending the implementation of whole-genome sequencing (WGS)-based surveillance for a deeper comprehension of disease patterns and an evolving AMR landscape.

Persistence of Campylobacter spp. in Poultry Flocks after Disinfection, Virulence, and Antimicrobial Resistance Traits of Recovered Isolates

To investigate the persistence risk of Campylobacter spp. in poultry farms, and to study the virulence and antimicrobial resistance characteristics in the recovered strains, we collected 362 samples from breeding hen flocks, before and after disinfection. The virulence factors were investigated by targeting the genes; flaA, cadF, racR, virB11, pldA, dnaJ, cdtA, cdtB, cdtC, ciaB, wlaN, cgtB, and ceuE by PCR. Antimicrobial susceptibility was tested and genes encoding antibiotic resistance were investigated by PCR and MAMA-PCR. Among the analyzed samples, 167 (46.13%) were positive for Campylobacter. They were detected in 38.7% (38/98) and 3% (3/98) of environment samples before and after disinfection, respectively, and in 126 (75.9%) out of 166 feces samples. In total, 78 C. jejuni and 89 C. coli isolates were identified and further studied. All isolates were resistant to macrolids, tetracycline, quinolones, and chloramphenicol. However, lower rates were observed for beta-lactams [ampicillin (62.87%), amoxicillin-clavulanic acid (47.3%)] and gentamicin (0.6%). The tet(O) and the cmeB genes were detected in 90% of resistant isolates. The bla_OXA-61 gene and the specific mutations in the 23S rRNA were detected in 87% and 73.5% of isolates, respectively. The A2075G and the Thr-86-Ile mutations were detected in 85% and 73.5% of macrolide and quinolone-resistant isolates, respectively. All isolates carried the flaA, cadF, CiaB, cdtA, cdtB, and cdtC genes. The virB11, pldA, and racR genes were frequent in both C. jejuni (89%, 89%, and 90%, respectively) and C. coli (89%, 84%, and 90%). Our findings highlight the high occurrence of Campylobacter strains exhibiting antimicrobial resistance with potential virulence traits in the avian environment. Thus, the improvement of biosecurity measures in poultry farms is essential to control bacterial infection persistence and to prevent the spread of virulent and resistant strains.

Distribution of virulence and antibiotic resistance genes in Campylobacter jejuni and Campylobacter coli isolated from broiler chickens in Tunisia

BACKGROUND

Thermo-tolerant Campylobacter species are the major cause of foodborne diseases worldwide. This study aimed to evaluate the prevalence of virulence genes and antibiotic resistance determinants in Campylobacter jejuni and Campylobacter coli isolates, and to investigate the relationship between these two traits.

METHODS

A total of 132 Campylobacter isolates from poultry were tested for the presence of 13 virulence genes; flaA, cadF, racR, virB11, pldA, dnaJ, cdtA, cdtB, cdtC, ciaB, wlaN, cgtB and ceuE. The mechanisms underlying antibiotic resistance phenotypes were also studied by PCR and MAMA-PCR.

RESULTS

PCR results revealed the presence of antimicrobial resistance genes in C. jejuni and C. coli as follows: cmeB (80% and 100%), tet(O) (100% and 80%), and the bla_OXA-61 (81% and 93%), respectively. None of these strains harbored the aphA-3 gene. The Thr-86-Ile mutation associated with resistance to quinolones was found in 90% of C. jejuni and 80% of C. coli isolates. While the A2075G and A2074C mutations linked to the erythromycin resistance were detected in 100% of both species. Virulence genes were prevalent and ranged from 40 to 100%. A positive relationship was revealed between cadF, racR, and ciaB genes and resistance to ampicillin, amoxicillin/clavulanic acid, chloramphenicol, and nalidixic acid, in C. jejuni. However, no association was observed for C. coli isolated strains.

CONCLUSION

This study provides for the first time an overview of antibiotic resistance mechanisms and pathogenic profiles of Campylobacter isolates, which emphasizes the potential risk for consumer health.

Occurrence of Campylobacter spp. and Phenotypic Antimicrobial Resistance Profiles of Campylobacter jejuni in Slaughtered Broiler Chickens in North-Western Romania

Campylobacteriosis is recognized as one of the most common food-borne zoonoses, with worldwide distribution, having undercooked poultry meat and other cross-contaminated foodstuffs as the main sources of human infections. The current study aimed to provide data on the occurrence of the thermophilic Campylobacter spp. in seven broiler chicken flocks, from three north-western Transylvanian counties of Romania, as well as to determine the antimicrobial resistance profile of the isolated C. jejuni strains. A total of 324 fresh cecal samples were collected during the slaughtering process, and screened for the presence of Campylobacter spp., using routine microbiological and molecular diagnostic tools. Overall, 85.2% (276/324; 95% CI 80.9-88.6) of the tested samples expressed positive results for Campylobacter spp., with dominant occurrence of C. coli towards C. jejuni (63.4% vs. 36.6%). From the six tested antimicrobials, the 101 isolated C. jejuni strains were resistant against ciprofloxacin (79.2%), nalidixic acid (78.2%), tetracycline (49.5%), and streptomycin (7.9%), but total susceptibility was noticed against erythromycin and gentamicin. Seven (6.9%) isolates exhibited multidrug resistance. The study results emphasize the role of broiler chicken as reservoir of Campylobacter infections for humans, as well as strengthen the necessity of the prudent using of antimicrobials in the poultry industry.

Relationships between Virulence Genes and Antibiotic Resistance Phenotypes/Genotypes in Campylobacter spp. Isolated from Layer Hens and Eggs in the North of Tunisia: Statistical and Computational Insights

Globally, Campylobacter is a significant contributor to gastroenteritis. Efficient pathogens are qualified by their virulence power, resistance to antibiotics and epidemic spread. However, the correlation between antimicrobial resistance (AR) and the pathogenicity power of pathogens is complex and poorly understood. In this study, we aimed to investigate genes encoding virulence and AR mechanisms in 177 Campylobacter isolates collected from layer hens and eggs in Tunisia and to assess associations between AR and virulence characteristics. Virulotyping was determined by searching 13 virulence genes and AR-encoding genes were investigated by PCR and MAMA-PCR. The following genes were detected in C. jejuni and C. coli isolates: tet(O) (100%/100%), bla_OXA-61 (18.82%/6.25%), and cmeB (100%/100%). All quinolone-resistant isolates harbored the Thr-86-Ile substitution in GyrA. Both the A2074C and A2075G mutations in 23S rRNA were found in all erythromycin-resistant isolates; however, the erm(B) gene was detected in 48.38% and 64.15% of the C. jejuni and C. coli isolates, respectively. The machine learning algorithm Random Forest was used to determine the association of virulence genes with AR phenotypes. This analysis showed that C. jejuni virulotypes with gene clusters encompassing the racR, ceuE, virB11, and pldA genes were strongly associated with the majority of phenotypic resistance. Our findings showed high rates of AR and virulence genes among poultry Campylobacter, which is a cause of concern to human health. In addition, the correlations of specific virulence genes with AR phenotypes were established by statistical analysis.

Genetic Signature and Serocompatibility Evidence for Drug Resistant Campylobacter jejuni

Campylobacteriosis, a foodborne illness, is one of the world's leading causes of gastrointestinal illness. This study investigates the link between human campylobacteriosis and the consumption of potentially contaminated food with Campylobacter jejuni. Three hundred sixty samples were collected from humans, chicken cloaca, raw chicken meat, unpasteurized milk, and vegetables. The chickens were obtained from licensed and non-licensed slaughterhouses, and only the necks and wings were studied. Samples were enriched under microaerobic conditions then cultured on the modified charcoal cefoperazone deoxycholate agar. Bacteria was identified by staining, biochemical testing, and molecular identification by the polymerase chain reaction for the virulence genes; hipO, asp, dnaJ, cadF, cdtA, cdtB, and cdtC. The genomic homogeneity of C. jejuni between human and chicken isolates was assessed by the serological Penner test and the pulse field gel electrophoresis (PFGE). Campylobacter was not detected in the vegetables and pasteurized milk, though, only twenty isolates from chickens and clinical samples were presumed to be Campylobacter based on their morphology. The biochemical tests confirmed that five isolates were C. coli, and fifteen isolates were C. jejuni including two isolates from humans, and the remaining were from chickens. The colonization of C. jejuni in chickens was significantly lower in necks (6.66%) obtained from licensed slaughterhouses compared to those obtained from non-licensed slaughterhouses (33.3%). The antimicrobial susceptibility test showed that all identified C. jejuni isolates were resistant to antibiotics, and the majority of isolates (53.5%) showed resistance against six antibiotics, though, all isolates were resistant to ciprofloxacin, tetracycline, and aztreonam. The Penner test showed P:21 as the dominant serotype in isolates from humans, necks, and cloaca. The serohomology of C. jejuni from human isolates and chicken necks, wings, and cloaca was 71%, 36%, 78%, respectively. The PFGE analysis of the pattern for DNA fragmentation by the restriction enzyme Smal showed a complete genotypic homology of C. jejuni human isolates and chicken necks compared to partial homology with cloacal isolates. The study brings attention to the need for effective interventions to ensure best practices for safe poultry production for commercial food chain supply to limit infection with foodborne pathogens, including Campylobacter.

Campylobacter spp. in Eggs and Laying Hens in the North-East of Tunisia: High Prevalence and Multidrug-Resistance Phenotypes

Despite the importance of eggs in the human diet, and unlike other products, for which food safety risks are widely investigated, information on the occurrence of Campylobacter and antimicrobial resistance in eggs and layer hen flocks is lacking in Tunisia. This study was conducted to determine the occurrence of Campylobacter and the antimicrobial resistance in layer hens and on eggshells. Thus, 366 cloacal swabs and 86 eggshell smear samples were collected from five layer hen farms in the North-East of Tunisia. The occurrence of Campylobacter infection, and the antimicrobial resistance rates and patterns, were analyzed. The occurrence rates of Campylobacter infection in laying hens and eggshells were 42.3% and 25.6%, respectively, with a predominance of C. jejuni (68.4%, 81.9%), followed by C. coli (31.6%, 18.2%). The antimicrobial susceptibility testing revealed high resistance rates against macrolides, tetracycline, quinolones, β-lactams, and chloramphenicol, with percentages ranging from 35.5% to 100%. All isolates were multidrug resistant (MDR) and five resistance patterns were observed. These results emphasized the risk to consumer health and the need to establish a surveillance strategy to control and prevent the emergence and the spread of resistant strains of Campylobacter in poultry and humans.

Assessment of biofilm formation by Campylobacter spp. isolates mimicking poultry slaughterhouse conditions

This research aimed to assess the biofilm formation ability of Campylobacter strains under temperature and oxygen stress conditions, similar to those found in the industrial environment, to explain the persistence of this pathogen on the poultry slaughter line. A collection of C. jejuni and C. coli isolates (n = 143) obtained from poultry samples (cecal content and neck skin), collected at slaughterhouse level, from diverse flocks, on different working days, was genotyped by flaA-restriction fragment length polymorphism (RFLP) typing method. A clustering analysis resulted in the assignment of 10 main clusters, from which 15 strains with different flaA-RFLP genotypes were selected for the assessment of biofilm formation ability and antimicrobial susceptibility. Biofilm assays, performed by crystal violet staining method, were conducted with the goal of mimicking some conditions present at the slaughterhouse environment, based on temperature, atmosphere, and contamination levels. Results indicated that many C. jejuni strains with similar flaA-RFLP profiles were present at the slaughterhouse on different processing days. All the strains tested (n = 15) were multidrug-resistant except for one. Biofilm formation ability was strain-dependent, and it appeared to have been affected by inoculum concentration, temperature, and tolerance to oxygen levels. At 10°C, adherence levels were significantly lower than at 42°C. Under microaerobic and aerobic atmospheres, at 42°C, 3 strains (C. jejuni 46E, C. jejuni 61C, and C. coli 65B) stood out, exhibiting significant levels of biofilm formation. C. jejuni strains 46E and 61C were inserted in clusters with evidence of persistence at the slaughterhouse for a long period of time. This study demonstrated that Campylobacter strains from broilers are capable of forming biofilms under conditions resembling the slaughterhouse environment. These results should be seen as a cue to improve the programs of hygiene implemented, particularly in those zones that can promote biofilm formation.

Antimicrobial Resistance, FlaA Sequencing, and Phylogenetic Analysis of Campylobacter Isolates from Broiler Chicken Flocks in Greece

Human campylobacteriosis caused by thermophilic Campylobacter species is the most commonly reported foodborne zoonosis. Consumption of contaminated poultry meat is regarded as the main source of human infection. This study was undertaken to determine the antimicrobial susceptibility and the molecular epidemiology of 205 Campylobacter isolates derived from Greek flocks slaughtered in three different slaughterhouses over a 14-month period. A total of 98.5% of the isolates were resistant to at least one antimicrobial agent. In terms of multidrug resistance, 11.7% of isolates were resistant to three or more groups of antimicrobials. Extremely high resistance to fluoroquinolones (89%), very high resistance to tetracycline (69%), and low resistance to macrolides (7%) were detected. FlaA sequencing was performed for the subtyping of 64 C. jejuni and 58 C. coli isolates. No prevalence of a specific flaA type was observed, indicating the genetic diversity of the isolates, while some flaA types were found to share similar antimicrobial resistance patterns. Phylogenetic trees were constructed using the neighbor-joining method. Seven clusters of the C. jejuni phylogenetic tree and three clusters of the C. coli tree were considered significant with bootstrap values >75%. Some isolates clustered together were originated from the same or adjacent farms, indicating transmission via personnel or shared equipment. These results are important and help further the understanding of the molecular epidemiology and antimicrobial resistance of Campylobacter spp. derived from poultry in Greece.

Antibiotic Resistance Profiles and Molecular Mechanisms of Campylobacter From Chicken and Pig in China

The purpose of this research was to characterize the antibiotic resistance profiles of Campylobacter spp. derived from chicken and pig feces collected from farms in Jiangsu Province, China, and to analyze the relevant resistance mechanisms among antimicrobial-resistant Campylobacter spp. isolates. Antibiotic susceptibility to nine antibiotic agents was tested with the microdilution method in 93 Campylobacter spp. (45 C. jejuni and 25 C. coli from chickens; 23 C. coli from pigs). High rates of resistance were observed to nalidixic acid (79.6%), erythromycin (75.3%), tetracycline (68.8%), azithromycin (66.7%), ciprofloxacin (64.5%), and gentamicin (35.5%), with a lower resistance rate to florfenicol (8.6%). The prevalence of the tested antibiotic resistance in C. coli was higher than in C. jejuni from chickens. The rate of antimicrobial resistance to ciprofloxacin in C. coli isolates from chickens was 100.0%, and the C. coli isolates from pigs were all resistant to erythromycin (100%). Most of C. jejuni (64.4%) and C. coli (64.5%) isolates displayed multi-drug resistance. All the Campylobacter spp. isolates resistant to fluoroquinolones had the C257T mutation in the gyrA gene. All 64 tetracycline-resistant Campylobacter spp. isolates were positive for the tetO gene. The tetA gene was also amplified in 6.5% of Campylobacter spp. isolates, whereas tetB was not detected among the isolates. The A2075G point mutation in the 23S rRNA gene occurred in 86.1% (62/72) of the macrolides-resistant Campylobacter spp. isolates, and the ermB gene was identified in 49 Campylobacter spp. isolates (30 C. jejuni and 19 C. coli). Amino acid insertions or mutations in the L4 and L22 ribosomal proteins were not linked to macrolide resistance. These results highlight the high prevalence of resistance to multiple antibiotics, particular macrolides, among Campylobacter spp. from chickens and pigs in Jiangsu Province, China, which is probably attributable to the overuse of antimicrobials in chicken and pig production. These findings recommend the more cautious use of critical antimicrobial agents in swine and poultry production. Stringent and continuous surveillance is required to reduce the drug-resistant campylobacteriosis in food animals and humans.

External contamination of broilers by Campylobacter spp. increases from the farm to the slaughterhouse

1. In this study, classical and molecular microbiological methods for detection and quantification of Campylobacter spp. were used to estimate their prevalence in faecal samples and skin swabs collected from 31 broiler flocks (20 farms) in Portugal, and measure the impact of transport-related factors on the expected rising excretion rates from the farm to the slaughterhouse. 2. Data on husbandry practices and transport conditions were gathered, including time in transit, distance travelled or ante-mortem plant-holding time. 3. A generalised linear mixed model was used to evaluate the significance of a potential post-transport rise in Campylobacter spp. counts and to assess risk determinants. 4. At least one flock tested positive for Campylobacter spp. in 80% of the sampled farms. At the slaughterhouse, Campylobacter spp. were detected in all faecal samples, C. jejuni being the most commonly isolated. 5. A post-transport rise of Campylobacter spp. counts from skin swabs was observed using classical microbiological methods (from a mean of 1.43 to 2.40 log₁₀ CFU/cm²) and molecular techniques (from a mean of 2.64 to 3.31 log₁₀ genome copies/cm²). 6. None of the husbandry practices or transport-related factors were found to be associated with Campylobacter spp. counts. 7. This study highlights the need for more research to better understand the multi-factorial nature of Campylobacter spp., a public health threat that was found to be highly prevalent in a sample of Portuguese poultry farms.

Comparison of different approaches to antibiotic restriction in food-producing animals: stratified results from a systematic review and meta-analysis

BACKGROUND

We have previously reported, in a systematic review of 181 studies, that restriction of antibiotic use in food-producing animals is associated with a reduction in antibiotic-resistant bacterial isolates. While informative, that report did not concretely specify whether different types of restriction are associated with differential effectiveness in reducing resistance. We undertook a sub-analysis of the systematic review to address this question.

METHODS

We created a classification scheme of different approaches to antibiotic restriction: (1) complete restriction; (2) single antibiotic-class restriction; (3) single antibiotic restriction; (4) all non-therapeutic use restriction; (5) growth promoter and prophylaxis restriction; (6) growth promoter restriction and (7) other/undetermined. All studies in the original systematic review that were amenable to meta-analysis were included into this substudy and coded by intervention type. Meta-analyses were conducted using random effects models, stratified by intervention type.

RESULTS

A total of 127 studies were included. The most frequently studied intervention type was complete restriction (n=51), followed by restriction of non-therapeutic (n=33) and growth promoter (n=19) indications. None examined growth promoter and prophylaxis restrictions together. Three and seven studies examined single antibiotic-class and single antibiotic restrictions, respectively; these two intervention types were not significantly associated with reductions in antibiotic resistance. Though complete restrictions were associated with a 15% reduction in antibiotic resistance, less prohibitive approaches also demonstrated reduction in antibiotic resistance of 9%-30%.

CONCLUSION

Broad interventions that restrict global antibiotic use appear to be more effective in reducing antibiotic resistance compared with restrictions that narrowly target one specific antibiotic or antibiotic class. Importantly, interventions that allow for therapeutic antibiotic use appear similarly effective compared with those that restrict all uses of antibiotics, suggesting that complete bans are not necessary. These findings directly inform the creation of specific policies to restrict antibiotic use in food-producing animals.

Prevalence and Antibiotic Resistance Patterns of Campylobacter spp. Isolated from Broiler Chickens in the North of Tunisia

The aim of the current study is to assess the prevalence of Campylobacter infection in broiler chickens, raised in intensive production conditions, and to evaluate the antimicrobial susceptibility of recovered Campylobacter isolates. A total of 590 cloacal swab samples were taken from 13 broiler chicken flocks in the North East of Tunisia. All samples were tested for the presence of thermophilic Campylobacter by culture and PCR, targeting the mapA and ceuE genes, respectively. Susceptibility to antimicrobial drugs was tested against 8 antibiotics. Prevalence of Campylobacter infection, relationship with geographic origins and seasons, antimicrobial resistance rates and patterns were analyzed. Total prevalence of Campylobacter infection in broiler flocks was in the range of 22.4%, with a predominance of C. jejuni (68.9%), followed by C. coli (31.1%). Positive association was highlighted between the infection level and the season (P < 0.001), but no link was emphasized considering the geographic origin. Antimicrobial susceptibility testing revealed very high resistance rates detected against macrolide, tetracycline, quinolones, and chloramphenicol, ranging from 88.6% to 100%. Lower resistance prevalence was noticed for β-lactams (47% and 61.4%) and gentamicin (12.9%). 17 R-type patterns were observed, and a common pattern was found in 30.3% of isolates. This study provides updates and novel data on the prevalence and the AMR of broiler campylobacters in Tunisia, revealing the occurrence of high resistance to several antibiotics and emphasizing the requirement of better surveillance and careful regulation of antimicrobials use.

Prevalence and Characteristics of Campylobacter Throughout the Slaughter Process of Different Broiler Batches

Handling and consumption of chicken meat are risk factors for human campylobacteriosis. This study was performed to describe the Campylobacter population in broiler carcasses and environmental samples throughout the slaughter process. Moreover, the genetic diversity and antimicrobial resistance of the Campylobacter strains were evaluated. Cloacal swabs, samples from carcasses at different stages, and environmental samples were collected thrice from the different flocks at the same abattoir located in Central Jiangsu, China. Campylobacter isolated from the three batches (n = 348) were identified as Campylobacter jejuni (n = 117) and Campylobacter coli (n = 151) by multiplex PCR. Characterization by multilocus sequence typing revealed a specific genotype of Campylobacter for each batch. Antimicrobial sensitivity to 18 antibiotics were analyzed for all selected strains according to the agar diffusion method recommended by the Clinical and Laboratory Standards Institute. Antibiotic susceptibility tests indicated that the majority of the tested isolates were resistant to quinolones (>89.7%). Less resistance to macrolide (59.8%), gentamicin (42.7%), amikacin (36.8%) was observed. Results showed that 94.0% of the tested strains demonstrated multidrug resistance.

Campylobacter coli in Organic and Conventional Pig Production in France and Sweden: Prevalence and Antimicrobial Resistance

The purpose of the study was to evaluate and compare the prevalence and antimicrobial resistance of Campylobacter coli in conventional and organic pigs from France and Sweden. Fecal or colon samples were collected at farms or at slaughterhouses and cultured for Campylobacter. The minimum inhibitory concentrations of ciprofloxacin, nalidixic acid, streptomycin, tetracycline, erythromycin, and gentamicin were determined by microdilution for a total of 263 French strains from 114 pigs from 50 different farms and 82 Swedish strains from 144 pigs from 54 different farms. Erythromycin resistant isolates were examined for presence of the emerging rRNA methylase erm(B) gene. The study showed that within the colon samples obtained in each country there was no significant difference in prevalence of Campylobacter between pigs in organic and conventional productions [France: conventional: 43/58 (74%); organic: 43/56 (77%) and Sweden: conventional: 24/36 (67%); organic: 20/36 (56%)]. In France, but not in Sweden, significant differences of percentages of resistant isolates were associated with production type (tetracycline, erythromycin) and the number of resistances was significantly higher for isolates from conventional pigs. In Sweden, the number of resistances of fecal isolates was significantly higher compared to colon isolates. The erm(B) gene was not detected in the 87 erythromycin resistant strains tested.

EMA and EFSA Joint Scientific Opinion on measures to reduce the need to use antimicrobial agents in animal husbandry in the European Union, and the resulting impacts on food safety (RONAFA)

EFSA and EMA have jointly reviewed measures taken in the EU to reduce the need for and use of antimicrobials in food-producing animals, and the resultant impacts on antimicrobial resistance (AMR). Reduction strategies have been implemented successfully in some Member States. Such strategies include national reduction targets, benchmarking of antimicrobial use, controls on prescribing and restrictions on use of specific critically important antimicrobials, together with improvements to animal husbandry and disease prevention and control measures. Due to the multiplicity of factors contributing to AMR, the impact of any single measure is difficult to quantify, although there is evidence of an association between reduction in antimicrobial use and reduced AMR. To minimise antimicrobial use, a multifaceted integrated approach should be implemented, adapted to local circumstances. Recommended options (non-prioritised) include: development of national strategies; harmonised systems for monitoring antimicrobial use and AMR development; establishing national targets for antimicrobial use reduction; use of on-farm health plans; increasing the responsibility of veterinarians for antimicrobial prescribing; training, education and raising public awareness; increasing the availability of rapid and reliable diagnostics; improving husbandry and management procedures for disease prevention and control; rethinking livestock production systems to reduce inherent disease risk. A limited number of studies provide robust evidence of alternatives to antimicrobials that positively influence health parameters. Possible alternatives include probiotics and prebiotics, competitive exclusion, bacteriophages, immunomodulators, organic acids and teat sealants. Development of a legislative framework that permits the use of specific products as alternatives should be considered. Further research to evaluate the potential of alternative farming systems on reducing AMR is also recommended. Animals suffering from bacterial infections should only be treated with antimicrobials based on veterinary diagnosis and prescription. Options should be reviewed to phase out most preventive use of antimicrobials and to reduce and refine metaphylaxis by applying recognised alternative measures.

Sensitivity to Enterocins of Thermophilic Campylobacter spp. from Different Poultry Species

Campylobacter spp. have been isolated from various animals, including poultry. They are rapidly transmitted throughout broiler sheds by the fecal-oral route. A promising strategy to reduce Campylobacter spp. in poultry may be done due to the beneficial properties of probiotic bacteria and their bacteriocins. In this study, inhibition spectrum/activity of different enterocins was evaluated against Campylobacter spp. (isolated from different poultry) to indicate further practical use of enterocins. Enterocins are antimicrobial proteinaceous substances produced mostly by enterococci. Feces from broiler chickens (10), laying hens (47), ostriches (140), and ducks (40) were screened. Altogether, 23 strains were allotted to the species Campylobacter jejuni and Campylobacter coli using MALDI TOF mass spectrometry and confirmed by genotyping (PCR method). In the feces of ostriches, Campylobacter spp. were not confirmed. Campylobacter spp. isolated from different poultry showed resistance to nalidixic acid, ciprofloxacin, and ampicillin. Interestingly, strains demonstrating antibiotic resistance revealed sensitivity to at least one of the nine enterocins used (except C. coli Kc1, SZ3, and C. jejuni 1/D). Almost 52% strains were inhibited by Ent A (P). Enterocins can therefore be used to prevent or reduce Campylobacter spp.; it is a basis for practical use.

Campylobacter in Poultry: Ecology and Potential Interventions

Avian hosts constitute a natural reservoir for thermophilic Campylobacter species, primarily Campylobacter jejuni and Campylobacter coli, and poultry flocks are frequently colonized in the intestinal tract with high numbers of the organisms. Prevalence rates in poultry, especially in slaughter-age broiler flocks, could reach as high as 100% on some farms. Despite the extensive colonization, Campylobacter is essentially a commensal in birds, although limited evidence has implicated the organism as a poultry pathogen. Although Campylobacter is insignificant for poultry health, it is a leading cause of food-borne gastroenteritis in humans worldwide, and contaminated poultry meat is recognized as the main source for human exposure. Therefore, considerable research efforts have been devoted to the development of interventions to diminish Campylobacter contamination in poultry, with the intention to reduce the burden of food-borne illnesses. During the past decade, significant advance has been made in understanding Campylobacter in poultry. This review summarizes the current knowledge with an emphasis on ecology, antibiotic resistance, and potential pre- and postharvest interventions.

Comparative analysis of antimicrobial resistance and genetic diversity of Campylobacter from broilers slaughtered in Poland

In the current study, the relationship of Campylobacter jejuni and Campylobacter coli strains isolated at slaughter was investigated using comparative analysis of antimicrobial resistance (AMR), virulence gene (VG) and PFGE profiling. A total of 254 Campylobacter isolates from poultry caeca and corresponding carcasses, including 139 C. jejuni and 115 C. coli strains were tested. The most prevalent resistance profiles observed in C. jejuni were ciprofloxacin, nalidixic acid and tetracycline (46 out of 139, 33.1% isolates) as well as ciprofloxacin, nalidixic acid, tetracycline and streptomycin among C. coli strains (34 out of 115, 29.6%). Multi-resistance was found more frequently among C. coli than C. jejuni (P<0.05). The presence of 11 virulence genes exhibited 19 different VG profiles in Campylobacter isolates tested. All Campylobacter strains were classified into 154 different PFGE types. Among them, 56 profiles (28 C. jejuni and 28 C. coli) were common for at least two isolates including 9 clusters covering from 4 to 9 strains. Campylobacter composite types generated by a combination of 154 PFGE types, 10 AMR profiles and 19 VG patterns divided 178 distinct types with 95% similarity. The majority of the composite profiles (76 for C. jejuni and 58 for C. coli; 75.3% in total) included only one bacterial isolate. Furthermore, 11 pairs of C. jejuni and 12 pairs of C. coli from caeca and the corresponding carcasses isolated from the same places possessed the identical PFGE, AMR and VG patterns. This study demonstrated that C. jejuni and C. coli isolated from poultry in Poland showed to have a high genetic diversity and a weak clonal population structure. However, the composite analysis revealed a strong evidence for cross-contamination of chicken carcasses during the slaughter process. Additionally, our results confirm that Campylobacter may easily contaminate poultry carcasses at slaughter process and spread around country. More than half of Campylobacter strains tested (50.4%) were resistant to at least two classes of antimicrobials, i.e. quinolones and tetracyclines, which may cause a public health risk.

A five-year study on prevalence and antimicrobial resistance of Campylobacter from poultry carcasses in Poland

During 2009-2013 a total of 2114 swab samples collected from broiler carcasses in all 16 voivodeships (administrative districts) of Poland were examined for the presence of Campylobacter jejuni and Campylobacter coli. The antimicrobial resistance of the isolates to ciprofloxacin, tetracycline and erythromycin using the MIC method was also tested. It was found that 1151 (54.4%) carcasses were contaminated with Campylobacter, with 50% of C. jejuni and C. coli species isolated from positive samples. The temporal trend in the prevalence of Campylobacter-positive samples demonstrated that the highest percentage of carcasses was contaminated during the first year of the survey (70.5%) whereas in the last year (2013) only 36.3% of broilers contained these bacteria. Antimicrobial resistance analysis showed that overall 939 (81.6%) of isolates were resistant to ciprofloxacin, 646 (56.1%) to tetracycline but only 28 (2.4%) to erythromycin. Significant differences in resistance profiles between C. jejuni and C. coli were observed with greater resistance level observed in the latter species. Furthermore, a significant increase in the percentage of C. jejuni resistant to ciprofloxacin (from 59.6% in 2009 to 85.9% in 2014) and to tetracycline (from 23.2% to 70.4%, respectively) was identified. Only 20 (1.7%) Campylobacter isolates displayed a multiresistance pattern.