Comparison of sampling techniques for detection of Arcobacter butzleri from chickens

A Systematic Analysis of Research on Arcobacter: Public Health Implications from a Food-Environment Interphase Perspective

This review maps the global research landscape of the public health implications of Arcobacter from the food–environment interphase using content analytics and integrated science mapping. The search term “Arcobacter” was used to retrieve relevant articles published in Web of Science and Scopus between 1991 to 2019. The number of articles included in the review was 524, with 1304 authors, 172 journal sources, and a collaborative index of 2.55. The annual growth rate of the publications was 9.74%. The most contributing author in the field was Houf K., with 40 publications, 26 h-index, and 2020 total citations. The most productive country was the USA (13.33%). The majority of the articles were published in English (96%) and in the Journal of Food Protection (8.02%). The highest research outputs were in the field of Microbiology (264). The frequently occurred keywords were Arcobacter, poultry, shellfish, cattle, and chicken. This study revealed a fair increase in the growth rate of Arcobacter-related research—especially in the area of isolation and detection of the pathogen in foods and food environments, as well as the pathogenesis and genetic diversity of the pathogen. Research themes in the area of prevalence and epidemiology seem to be underexplored.

Detection of Arcobacter species in different intestinal compartments of broiler chicken during slaughter and processing

Arcobacter spp. are commonly present on meat products. However, the source of contamination on chicken meat is under dispute. Since different studies reported contradictory results on the occurrence of Arcobacter spp. inside the intestinal tract of chicken, our study examined four intestinal compartments at four significant production steps during broiler slaughter and processing in the slaughterhouse. Altogether, 157 intestinal tracts from 19 flocks were examined qualitatively and semiquantitatively applying a selective enrichment. Further verification was performed by mPCR and rpoB sequencing. Arcobacter spp. were only detected sporadically in intestinal contents after bleeding (2/32) and in none after scalding (0/32). After defeathering, Arcobacter spp. were detected in 62% (18/29) of the intestinal contents with 28% (8/29) of the duodenal, 21% (6/29) of the jejunal, 3% (1/29) of the cecal, and 55% (16/29) of the colonic samples tested positive with loads up to 24,000 MPN/g in the colonic content. Further 88% (7/8) of colonic tissue samples were tested positive. After evisceration, the prevalences (58/64) and loads of Arcobacter spp. display comparable levels in the intestinal contents like after defeathering. In conclusion, our data point out that Arcobacter spp. are most likely detected in the colonic intestinal compartment of the chicken after defeathering and evisceration. Therefore, not only cross-contamination originating from the environment inside the slaughterhouse may cause carcass contamination with Arcobacter spp. on broiler chicken carcasses. The detection of Arcobacter spp. in duodenal and jejunal contents as well as in the colonic tissue indicates that there possibly exists an Arcobacter reservoir inside the chicken.

Multilocus sequence typing and biocide tolerance of Arcobacter butzleri from Danish broiler carcasses

Background

Arcobacter spp. have in recent years received increasing interest as potential emerging enteropathogens and zoonotic agents. They are associated with various animals including poultry and can be isolated from meat products. The possibilities of persistence and cross-contamination in slaughterhouses during meat processing are not well established. We have evaluated the occurrence and persistence of Arcobacter spp. in a Danish slaughterhouse and determined the sensitivity of isolates to sodium hypochlorite, a commonly used biocide.

Results

Arcobacter contamination was examined in a broiler slaughterhouse by selective enrichment of 235 swabs from the processing line during two production days and after sanitizing in between. In total 13.6% of samples were positive for A. butzleri with the majority (29 of 32 isolates) originating from the evisceration machine. No Arcobacter spp. was isolated after cleaning. A. butzleri isolates confirmed by PCR were typed by multilocus sequence typing (MLST) resulting in 10 new sequence types (STs). Two sequence types were isolated on both processing days. Minimum inhibitory concentration (MIC) to sodium hypochlorite was determined to 0.5% hypochlorite biocide (500 ppm chlorine) for most isolates, which allows growth of A. butzleri within the working concentration of the biocide (0.2 - 0.5%).

Conclusions

A. butzleri was readily isolated from a Danish broiler slaughterhouse, primarily in the evisceration machine. Typing by MLST showed high strain variability but the recurrence of two STs indicate that some persistence or cross-contamination takes place. Importantly, the isolates tolerated sodium hypochlorite, a biocide commonly employed in slaughterhouse sanitizing, at levels close to the disinfection concentration, and thus, A. butzleri may survive the disinfection process although this was not observed in our study.

Prevalence of Campylobacter spp. in raw retail poultry on sale in Northern Ireland

A year-long survey of fresh, retail poultry products on sale in Northern Ireland was undertaken to define the prevalence of Campylobacter spp. by using protocols based on ISO (standard) 10272-1:2006. Incubation at 37 and 42 degrees C was undertaken to increase the diversity of isolates obtained. Overall, 652 isolates were identified as Campylobacter spp. by using PCR and amplified fragment length polymorphic typing. Phenotyping wrongly identified 21% of isolates. Prevalences of Campylobacter found were chicken, 91% (n = 336); turkey, 56% (n = 77); and duck, 100% (n = 17). Prevalence rates for chicken produced in Northern Ireland, Scotland, England, and Wales were similar, with a mean value of 91%. The prevalences in product from the latter two countries were much higher than were found in two United Kingdom-wide surveys of chicken. The incubation temperature did not affect the relative proportions of the species isolated (P > 0.05). Campylobacter jejuni composed 64.6% of isolates, Campylobacter coli, 27.4%, and Campylobacter lari, 1%. Most cases of human campylobacteriosis are caused by C. jejuni and C. coli. The overall Campylobacter prevalence results are consistent with Northern Ireland surveys undertaken since 2000, and indicate that United Kingdom strategies to control Campylobacter in chicken have not had a significant effecton the prevalence of this pathogen in retail products on sale in Northern Ireland.

Specific PCR detection of Arcobacter butzleri, Arcobacter cryaerophilus, Arcobacter skirrowii, and Arcobacter cibarius in chicken meat

An enrichment PCR assay using species-specific primers was developed for the detection of Arcobacter butzleri, Arcobacter cryaerophilus, Arcobacter skirrowii, and Arcobacter cibarius in chicken meat. Primers for A. cryaerophilus, A. skirrowii, and A. cibarius were designed based on the gyrA gene to amplify nucleic acid fragments of 212, 257, and 145 bp, respectively. The A. butzleri-specific primers were designed flanking a 203-bp DNA fragment in the 16S rRNA gene. The specificity of the four primer pairs was assessed by PCR analysis of DNA from a panel of Arcobacter species, related Campylobacter, Helicobacter species, and other food bacteria. The applicability of the method was then validated by testing 42 fresh retail-purchased chicken samples in the PCR assay. An 18-h selective preenrichment step followed by PCR amplification with the four Arcobacter primer sets revealed the presence of Arcobacter spp. in 85.7% of the retail chicken samples analyzed. A. butzleri was the only species present in 50% of the samples, and 35.7% of the samples were positive for both A. butzleri and A. cryaerophilus. A. skirrowii and A. cibarius were not detected in any of the chicken samples analyzed. The enrichment PCR assay developed is a specific and rapid alternative for the survey of Arcobacter contamination in meat.

Incidence of Arcobacter spp. in poultry: quantitative and qualitative analysis and PCR differentiation

Arcobacter is part of the family Campylobacteraceae. As with the genus Campylobacter, Arcobacter is found responsible for human gastrointestinal infection, and it is assumed to originate from poultry meat sources. Samples from poultry slaughtering originating from a broiler slaughterhouse and a turkey slaughterhouse were analyzed for Arcobacter. Five broiler flocks and five turkey flocks were analyzed in the course of slaughtering and processing for the prevalence of Arcobacter. The prevalence in broilers was 43.0%, while turkey samples were contaminated with 18.2% of positive samples. The numbers of Arcobacter present on turkey skin samples ranged between 1.7 and 2.4 log CFU/cm2. The prevalence changes during processing showed an increase after chilling in broilers, whereas there was a constant decrease in turkey processing. Species identification showed that all three Arcobacter spp. of relevance in human infection could be isolated, with A. butzleri being found at higher prevalence, which was followed by A. skirrowii and A. cryaerophilus.

Detection of Arcobacter spp. in piggery effluent and effluent-irrigated soils in southeast Queensland

AIMS

To investigate the occurrence and levels of Arcobacter spp. in pig effluent ponds and effluent-treated soil.

METHODS AND RESULTS

A Most Probable Number (MPN) method was developed to assess the levels of Arcobacter spp. in seven pig effluent ponds and six effluent-treated soils, immediately after effluent irrigation. Arcobacter spp. levels in the effluent ponds varied from 6.5 x 10(5) to 1.1 x 10(8) MPN 100 ml(-1) and in freshly irrigated soils from 9.5 x 10(2) to 2.8 x 10(4) MPN g(-1) in all piggery environments tested. Eighty-three Arcobacter isolates were subjected to an abbreviated phenotypic test scheme and examined using a multiplex polymerase chain reaction (PCR). The PCR identified 35% of these isolates as Arcobacter butzleri, 49% as Arcobacter cryaerophilus while 16% gave no band. All 13 nonreactive isolates were subjected to partial 16S rDNA sequencing and showed a high similarity (>99%) to Arcobacter cibarius.

CONCLUSIONS

A. butzleri, A. cryaerophilus and A. cibarius were isolated from both piggery effluent and effluent-irrigated soil, at levels suggestive of good survival in the effluent pond.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study to provide quantitative information on Arcobacter spp. levels in piggery effluent and to associate A. cibarius with pigs and piggery effluent environments.

Discrepancy Between the Occurrence of Arcobacter in Chickens and Broiler Carcass Contamination

Both Campylobacter and Arcobacter are commonly present on broiler carcasses. For Campylobacter, the superficial contamination originates predominantly from fecal contamination during slaughter. In contrast with Campylobacter, the source of the Arcobacter contamination is not clear. In several studies, arcobacters have been isolated in poultry processing plants from the carcasses and slaughter equipment, but not from the intestinal content. In literature, contradictory reports about the Arcobacter colonization of the chicken gut have been published. In most of those studies, arcobacters were not isolated from cecal content nor from litter or the feathers, though some studies reported the isolation of arcobacters from cloacal swab samples. The present study assessed if arcobacters are part of the chicken intestine, skin, or feather flora. Because no isolation protocol has been validated for poultry intestinal content, a previously developed Arcobacter isolation procedure for feces from livestock animals was first validated. With this method, a good repeatability, in-lab reproducibility and sensitivity, and a good suppression of the chicken fecal accompanying flora were achieved when 125 mg/L of 5-fluorouracil, 10 mg/L of amphotericine B, 100 mg/L of cycloheximide, 16 mg/L of cefoperazone, 64 mg/L of novobiocine, and 64 mg/L of trimethoprim were applied. The validated method was used to examine the presence of arcobacters in and on living chickens of 4 flocks at slaughter age. Because arcobacters were not isolated from the intestinal tract nor from the skin or feathers of the birds, this study was not able to identify arcobacters as part of the intestinal or skin flora, nor could confirm the role of process water as reservoir. However, the results clearly demonstrated that the time period for processing the samples and the way of sample collection are crucial in the interpretation of epidemiological studies. As the reservoir of the carcass contamination remains unidentified, studies about the capacity of arcobacters to colonize the chicken intestinal tract may contribute in the assessment of the transmission routes of this emerging foodborn pathogen.

Prevalence of Arcobacter species in market-weight commercial turkeys

The prevalence of Arcobacter in live market weight turkeys was determined for six Midwestern commercial flocks at three intervals. Samples (n = 987) were collected from cloaca, feathers, ceca, crop, drinkers and environmental samples on farms and from carcasses at slaughter. Initially, EMJH-P80 and CVA isolated Arcobacter from 7.1% (40 of 564) of samples, while Arcobacter enrichment broth and selective agar recovered the microbe in 4.7% of samples (23 of 489 samples). Although EMJH-P80 coupled with CVA yielded Arcobacter more frequently, the selectivity of the modified Arcobacter agar enhanced the recognition of Arcobacter colonies. A multiplex PCR was used to identify all Arcobacter species and to differentiate Arcobacter butzleri. The low prevalence of Arcobacter detected in cloacal swab (2.0%, 6 of 298 samples) and cecal contents (2.1%, 3 of 145 samples) suggests that Arcobacter infrequently colonizes the intestinal tract. Despite its low prevalence in live turkeys, Arcobacter spp. were identified in 93% of carcass swabs (139 of 150 samples). The overall prevalence of Arcobacter in drinker water decreased from 67% (31 of 46 samples) in the summer of 2003 to 24.7% (18 of 73 samples) during resampling in the spring of 2004 and was inversely related to the chlorination level.

Prevalence of Arcobacter and Campylobacter on broiler carcasses during processing

Broiler carcasses (n=325) were sampled in a U.S. commercial poultry processing plant for the prevalence of Arcobacter and Campylobacter at three sites along the processing line: pre-scald, pre-chill and post-chill. Samples (75-125 broilers per site) were collected during five plant visits from August to October of 2004. Arcobacter was recovered from pre-scald carcasses more frequently (96.8%) than from pre-chill (61.3%) and post-chill carcasses (9.6%). Campylobacter was isolated from 92% of pre-scald carcasses, 100% of pre-chill carcasses, and 52% of post-chill carcasses. In total, Arcobacter was isolated from 55.1% (179 of 325), while Campylobacter was isolated from 78.5% (255 of 325) of the carcasses from the three collection sites. For Arcobacter identification, a species-specific multiplex PCR showed that A. butzleri was the most prevalent species (79.1%) followed by A. cryaerophilus 1B (18.6%). A. cryaerophilus 1A was found at low levels (2.3%). PCR identified the most common Campylobacter species as C. jejuni (87.6%) followed by C. coli (12.4%). Overall, significant contamination of broiler carcasses by Arcobacter was observed, although less than that found for Campylobacter. From pre-scald to post-chill, a far greater reduction in Arcobacter numbers was observed than for Campylobacter. Our results for Arcobacter, obtained from the same environment as the closely related pathogen Campylobacter, will aid in the development of control measures for this emerging pathogen.

Relevant aspects of Arcobacter spp. as potential foodborne pathogen

Arcobacter species are Gram-negative spiral-shaped organisms belonging to the family Campylobacteraceae that can grow microaerobically or aerobically. The Arcobacter organisms also have the ability to grow at 15 degrees C, which is a distinctive feature that differentiates Arcobacter species from Campylobacter species. Cultural detection of Arcobacter is generally performed by an enrichment step and takes 4 to 5 days. In the last few years, several studies comparing different culture-based protocols have been published. Furthermore, DNA-based assays have also been established for rapid and specific identification of Arcobacter spp. Recent evidence suggests that Arcobacter, especially A. Butzleri, may be involved in human enteric diseases. Moreover, A. butzleri has also occasionally been found in cases of human extraintestinal diseases. However, up to now, little is known about the mechanisms of pathogenicity or potential virulence factors of Arcobacter spp. There is evidence that livestock animals may be a significant reservoir of Arcobacter spp. and over the last few years, the presence of these organisms in raw meat products as well as in surface and ground water has received increasing attention. In view of control measures to be used to prevent or to eliminate the hazard of Arcobacter spp. in food, several treatments have been evaluated for their effectiveness. While the role of Arcobacter spp. in human disease awaits further evaluation, a precautionary approach is advisable. Measures aimed at reduction or eradication of Arcobacter from the human food chain should be encouraged. With this article, we review the recent literature on this organism with a special emphasis on the information relevant to food safety.