家禽养殖过程中弯曲菌流行病学的研究进展

弯曲菌作为一种人兽共患的食源性病原菌,是引起全球范围内人类细菌性胃肠炎的主要病原菌。家禽是弯曲菌的自然宿主,在弯曲菌的流行中扮演着非常重要的角色。养殖过程中家禽感染弯曲菌后不表现出任何临床症状,但可持续向外界排菌,引起人类及其他动物感染发病,造成了严重的健康危害和经济损失。因此,控制或清除家禽弯曲菌是预防和控制人类弯曲菌病的重要前提。而在家禽养殖过程中开展弯曲菌的流行性监测工作对预防和控制弯曲菌具有重要意义。本文旨在对近年来家禽养殖过程中弯曲菌的流行现状、感染与传播及分子溯源技术等研究进展进行综述,以期为今后农场中家禽弯曲菌的流行和防控提供数据支持。     

Sources and spread of thermophilic Campylobacter spp. during partial depopulation of broiler chicken flocks

The practice of partial depopulation or thinning (early removal of a portion of birds from a commercial broiler flock) is a reported risk factor for Campylobacter colonization of residual birds because of the difficulty in maintaining biosecurity during the thinning process. The effect of this practice was studied in detail for 51 target flocks, each at a different growing farm belonging to one of seven major poultry companies throughout the United Kingdom. On 21 of these farms, the target flock was already colonized by Campylobacter, and at slaughter all cecal samples examined were positive, with a mean of 8 log CFU/g. An additional 27 flocks became positive within 2 to 6 days of the start of thinning and had similarly high levels of cecal carriage at slaughter. Just before the thinning process, Campylobacter was isolated frequently from the farm driveways, transport vehicles, equipment, and personnel. Strains from seven farms on which flocks became colonized after thinning were examined by pulsed-field gel electrophoresis typing. An association was found between strains occurring at specific sampling sites and those isolated subsequently from the thinned flocks. The results indicated that particular strains had spread from one farm to another when the farms were jointly owned by the same company and employed the same bird-catching teams and/or vehicles. These results highlight the need for better hygiene control in relation to catching equipment and personnel and more effective cleaning and disinfection of vehicles and bird-transport crates.     

Diversity of flaA genotypes among Campylobacter jejuni isolated from six niche-market poultry species at farm and processing

PCR-restriction fragment length polymorphism of the flagellin (flaA) gene in Campylobacter jejuni was used to determine the relationships of isolates collected at the farm and throughout processing for six niche-market poultry species. This study focused on two specialty chicken products, poussin and free range, and four other specialty products, squab, duck, guinea fowl, and quail. Cloacal and carcass samples were collected from three flocks from each of the six niche species. Three processing plants in California participated in a 2-year investigation. A total of 773 isolates from farm, posttransport, and the processing plants were genotyped, yielding a total of 72 distinct flaA profiles for the six commodities. Genetic diversity of C. jejuni at the farm was greatest for ducks with up to 12 distinct flaA types in two flocks and least for squab 1 flaA type between two farms. For two of the guinea fowl flocks, one free-range flock, two squab flocks, and all three poussin flocks, the flaA types recovered at the prepackage station matched those from the farm. Cross-contamination of poultry carcasses was supported by the observation of flaA types during processing that were not present at the farm level. New C. jejuni strains were detected after transport in ducks, guinea fowl, and free-range chickens. Postpicker, postevisceration, and prewash sampling points in the processing plant yield novel isolates. Duck and free-range chickens were the only species for which strains recovered within the processing plant were also found on the final product. Isolates recovered from squab had 56 to 93% similarity based on the flaA types defined by PCR-restriction fragment length polymorphism profiles. The 26 duck isolates had genetic similarities that ranged from 20 to 90%. Guinea fowl and free-range chickens each had 40 to 65% similarity between isolates. Poussin isolates were 33 to 55% similar to each other, and quail isolates were 46 to 100% similar. Our results continue to emphasize the need to clean processing equipment and posttransport crates in order to decrease cross contamination between flocks. This study also determined that several strains of C. jejuni had unique flaA types that could only be recovered in their host species.     

Occurrence of Campylobacter spp. in poultry and poultry products for sale on the Polish retail market

In 2007 and 2008, a monitoring study was carried out in Poland to examine the occurrence of thermotolerant Campylobacter spp. in raw and cooked chicken products available on the retail market. A total of 912 samples were tested: 443 samples of raw chicken meat, 146 samples of giblets, and 323 ready-to-eat poultry products (150 samples of spit-roasted chicken, 56 samples of smoked chicken, and 117 samples of paté and cold meats). A high level of contamination of raw chicken meat (51.7% of samples) and chicken giblets (47.3% of samples) was detected. However, thermotolerant Campylobacter spp. were found in only 1.2% of the ready-to-eat poultry products.     

Occurrence of Campylobacter and Listeria monocytogenes in a poultry processing plant

The occurrence of Campylobacter and Listeria monocytogenes was studied in 645 samples from surfaces, water, and poultry products (chicken carcasses, chicken parts, viscera, and spoils) in a poultry processing plant in southern Brazil. The automated mini-VIDAS system was used to detect the presence of Campylobacter and L. monocytogenes on the samples. The positive samples were confirmed by conventional methods. Campylobacter and L. monocytogenes were found in 16.6 and 35.6% of the analyzed samples, respectively. The sampling points with the highest Campylobacter incidence were intestine (63.3%, 19 of 30 samples), gallbladder (46.7%, 14 of 30), carcasses before evisceration (33.33%, 10 of 30), and carcasses after plucking (30%, 9 of 30). For L. monocytogenes, the majority of positive samples were from frozen breast (100%, 15 of 15 samples), frozen wing (93.3%, 14 of 15), fresh breast (83.3%, 25 of 30), fresh wing (80%, 24 of 30), skin of breast and leg (76.7%, 23 of 30), frozen leg (60%, 9 of 15), and fresh leg (50%, 15 of 30).     

Pre-harvest surveillance of Campylobacter and Salmonella in Danish broiler flocks: a 2-year study.

In national surveillance programmes of broiler flocks carried out in Denmark during 1998 and 1999, 89,110 samples for Campylobacter representing 8911 broiler flocks were taken at 10 different abattoirs, and 44,550 samples for Salmonella were taken from the same flocks in the broiler houses at the farms. Of the swabs, 42.5% were Campylobacter positive. Most positive samples were found during July, August and September, while the lowest number of positive samples were found during January, February, March and April. Of the flocks, 5.5% were Salmonella positive, but no seasonal variation was observed. For each flock, the presence of Campylobacter and Salmonella was recorded in order to estimate the possible correlation between colonisation with the two pathogens. In conclusion, no significant effects on intensive cleaning and disinfection procedures on Campylobacter occurrence could be demonstrated, and no significant correlation between occurrence of Campylobacter and Salmonella infections in Danish broilers could be demonstrated which is in contrast to previous observations on concurrent colonisation of broilers with these two zoonotic pathogens.     

Occurrence of selected foodborne pathogens on poultry and poultry giblets from small retail processing operations in Trinidad

We conducted a study to determine quantitatively and qualitatively the presence of Campylobacter spp., Escherichia coli, staphylococci, total coliforms, total aerobic bacteria, and Salmonella on broiler carcasses from selected small retail processors in Trinidad. We used standard media and procedures for detection and quantification. All carcass and weep samples were positive for aerobic bacteria, E. coli, total coliforms, and staphylococci. Significant differences in the mean counts of aerobic bacteria were observed for samples of carcass (P = 0.001), weep (P = 0.038), and liver and heart (P = 0.017). There was a significant difference (P < 0.05) in the prevalence of E. coli and Campylobacter for liver and heart samples and gizzard samples across various areas (health divisions) in Trinidad and for Campylobacter jejuni and Campylobacter coli for offal samples. The prevalence of Salmonella in carcass, drip, gizzard, and liver and heart samples was 7.3, 3.1, 2.1, and 1.0%, respectively, and three serotypes, Salmonella Kiambu (53.8%), Salmonella Kentucky (38.5%), and Salmonella Mbandaka (7.7%) were isolated. Of the six groups of microbes considered with respect to sale activity, the differences in the prevalence of Campylobacter in medium-activity sale shops (95.8%) and low-activity sale shops (83.3%) and the mean counts of staphylococci for medium-activity sale shops (5.5 +/- 0.9) and low-activity sale shops (5.1 +/- 0.8) were statistically significant (P < 0.05). Carcasses rinsed in a stagnant system had a significantly higher (P < 0.05) prevalence (92.3%) and mean count per milliliter (3.1 +/- 0.7) for Campylobacter compared with 77.8% and 2.7 +/- 0.7 for shops that rinsed with constantly running water. The frequency of rinse water change significantly (P = 0.04) affected the prevalence of Salmonella on carcasses. It is recommended that a quality control system be introduced for these shops, particularly with respect to evisceration and rinsing practices.     

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.     

Prevalence and diversity of Campylobacter jejuni in pig herds on farms with and without cattle or poultry

The prevalence and diversity of Campylobacter jejuni was investigated in pig herds on farms with and without cattle or poultry production. A bacteriological screening of pig cecal samples from 247 finisher herds was carried out at the slaughter-house. Subsequently, a follow-up study was conducted in 24 herds (either with or without prior C. jejuni isolation from pigs) in which fecal samples were collected from pigs and, if present, cattle and poultry. Samples were analyzed for presence of Campylobacter, and subsequent analysis included species identification, serotyping, and, for selected strains, pulsed-field gel electrophoresis typing. In the slaughterhouse screening, C. jejuni was isolated from pigs in 21 (8.5%) herds, but no significant difference in prevalence was found between herd types (pigs, pigs and cattle, pigs and poultry). At the slaughterhouse, C. jejuni and Campylobacter coli prevalence in pigs was 2.3 and 90.1%, respectively. In the follow-up study, herd prevalence of C. jejuni was 8.3%, whereas C. jejuni and C. coli were isolated from 0.8 and 92.0% of pigs, respectively. In mixed production herds, C. jejuni predominated in cattle (42.7%) and poultry (31.6%), whereas C. jejuni was only isolated from 1.3 to 2.5% of pigs in these herds. There were no significant differences in C. jejuni or C. coli prevalence in pigs, cattle, and poultry between herds with and without prior C. jejuni isolation at the slaughterhouse. Pulsed-field gel electrophoresis typing did not yield evidence of C. jejuni transmission between cattle or poultry and pigs in mixed production herds. In contrast, pulsed-field gel electrophoresis analysis showed indistinguishable serotypes of C. coli in pigs and cattle in two herds. Verification of C. jejuni-positive pig samples showed that individual pigs can excrete high levels of C. jejuni and that mixed infection with C. jejuni and C. coli was common in C. jejuni-positive pigs. The results of our study suggest that transmission of C. jejuni between pigs and cattle or poultry in mixed production herds occurs infrequently. Detection of indistinguishable C. coli isolates in two herds, however, might indicate the existence of low-level transmission between pigs and cattle in herds of mixed production.     

Occurrence and resistance to antibiotics of Campylobacter jejuni and Campylobacter coli in animals and meat in northeastern Italy

A study was carried out in northeastern Italy during 2000 and 2001 to investigate the occurrence of Campylobacter jejuni and Campylobacter coli in animals, cattle, pigs, and broilers, and raw meat, beef, pork, and chicken. Campylobacter spp. were detected in 53.9% of the cattle, 63.5% of the pigs, and 82.9% of the broilers examined. Chicken meat was frequently contaminated (81.3%), while lower rates were found in pork meat (10.3%) and beef (1.3%). The resistance to antibiotics of the strains was also investigated, and compared to that of human clinical isolates. C. coli was generally more resistant than C. jejuni. Resistance to quinolones was frequently observed in C. coli isolated in chicken meat (78.6%); slightly lower rates were found in C. jejuni isolated in broilers (42.2%), chicken meat (52.8%), and humans (38.2%). C. coli was also frequently resistant to tetracycline in all sources, while resistance to streptomycin was most frequently observed in pig isolates (89.4%).     

Genetic diversity of Arcobacter and Campylobacter on broiler carcasses during processing

Broiler carcasses (n=325) were sampled at three sites along the processing line (prescalding, prechilling, and postchilling) in a commercial poultry processing plant during five plant visits from August to October 2004. Pulsed-field gel electrophoresis (PFGE) was used to determine the genomic fingerprints of Camospylobacter coli (n=27), Campylobacter jejuni (n=188), Arcobacter butzleri (n=138), Arcobacter cryaerophilus 1A (n=4), and A. cryaerophilus 1B (n=31) with the restriction enzymes SmaI and KpnI for Campylobacter and Arcobacter, respectively. Campylobacter species were subtyped by the Centers for Disease Control and Prevention PulseNet 24-h standardized protocol for C. jejuni. A modification of this protocol with a different restriction endonuclease (KpnI) and different electrophoresis running conditions produced the best separation of restriction fragment patterns for Arcobacter species. Both unique and common PFGE types of Arcobacter and Campylobacter strains were identified. A total of 32.8% (57 of 174) of the Arcobacter isolates had unique PFGE profiles, whereas only 2.3% (5 of 215) of the Campylobacter isolates belonged to this category. The remaining Arcobacter strains were distributed among 25 common PFGE types; only eight common Campylobacter PFGE types were observed. Cluster analysis showed no associations among the common PFGE types for either genus. Each of the eight common Campylobacter types consisted entirely of isolates from one sampling day, whereas more than half of the common Arcobacter types contained isolates from different sampling days. Our results demonstrate far greater genetic diversity for Arcobacter than for Campylobacter and suggest that the Campylobacter types are specific to individual flocks of birds processed on each sampling day.     

The sensitivity and specificity of fecal and cecal culture for the detection of Campylobacter in Dutch broiler flocks quantified by Bayesian analysis

Dutch broiler flocks are routinely tested for the presence of thermotolerant Campylobacter spp. using a standard cultural procedure for fecal and cecal samples. The objective of this study was to estimate the sensitivity and specificity of fecal and cecal culture for detection of Campylobacter colonization in broiler flocks in absence of a gold standard. Data from 1600 flocks were used from two different populations, whereby only flocks with both fecal and cecal culture results were included in the analysis. Latent class analysis using Bayesian inference was applied to generate the test characteristics of fecal and cecal culture. Two statistical models assuming conditional dependence of both tests on Campylobacter status were used to compare the results. On flock level, the sensitivity of the fecal culture was found to be 21% (95% CI: 12, 31) and 23% (95% CI: 13, 60), and the specificity was 98% (95% CI: 94, 99) and 97% (95% CI: 92, 99) for the two models, respectively. The sensitivity of the cecal culture was 64% (95% CI: 37, 89) and 66% (95% CI: 39, 90), and the specificity was 98% (95 CI: 94, 99) and 95% (95% CI: 72, 99) in respective models. The implications of a low sensitivity as in the case of the fecal culture is important for the design and interpretation of monitoring programmes and may result in excessive false negative test results. Although cecal culture is the more sensitive test, substantial misclassification of infected flocks may still occur.     

Occurrence of fastidious Campylobacter spp. in fresh meat and poultry using an adapted cultural protocol

This study used an adapted cultural protocol for the recovery of fastidious species of Campylobacter, to gain a more accurate understanding of the diversity of Campylobacter populations in fresh meats. Chicken (n=185), pork (n=179) and beef (n=186) were collected from supermarkets and butchers throughout the Republic of Ireland. Samples were enriched in Campylobacter enrichment broth for 24h under an atmosphere of 2.5% O(2), 7% H(2), 10% CO(2), and 80.5% N(2). The enriched samples were then filtered onto non-selective Anaerobe Basal Agar supplemented with lysed horse blood using mixed ester filter membranes. Isolates were identified by both genus and species-specific PCR assays and biochemical testing. The incidence of campylobacters on beef (36%) was significantly higher than on pork (22%) or chicken (16%), and far exceeds previously reported prevalence levels. The method was successful in recovering 7 species of Campylobacter, including the fastidious spp. C. concisus and C. mucosalis, from chicken meat, and 10 species, including C. concisus, C. curvus, C. mucosalis, C. sputorum, and C. upsaliensis, from minced beef. The isolation of C. concisus and C. upsaliensis from meat in this study is of particular significance, due to their emerging clinical relevance. The results of this study confirm that the diversity of Campylobacter species on fresh meats is greater than previously reported and highlights the bias of cultural methods towards the recovery of C. jejuni.     

Changes in the microbial flora,chlorophenols and chloroanisoles in broiler house litter during a chicken rearing cycle

The changes in the microbial flora, chlorophenol loss, and chloroanisole production have been studied in the litter from four broiler houses through a single rearing cycle. An increase in species of Scopulariopsis and Aspergillus over the first 4 to 5 weeks of the rearing cycle coincided with a decrease in the levels of 2, 4, 6-tri-, 2, 3, 4, 6-tetra-, and pentachlorophenols, a rise in p^H and moisture content of the litter and a decline in the fungal species normally present in the fresh shavings. The maximum levels of chloroanisoles occurred at approximately the same stage of the rearing cycle as the highest viable count of the predominant litter fungi.     

Incidence of Salmonella, Campylobacter jejuni, Campylobacter coli, and Listeria monocytogenes in poultry carcasses and different types of poultry products for sale on the Belgian retail market.

From January 1997 to May 1998, 772 samples of poultry carcasses and poultry products for sale on the retail market in Belgium were analyzed for the presence of Salmonella spp., Salmonella Enteritidis, Campylobacter jejuni, C. coli, and Listeria monocytogenes per 100 cm2 or 25 g. Poultry samples were contaminated with Salmonella (36.5%), C. jejuni and C. coli (28.5%), and L. monocytogenes (38.2%). In about 12.3% of the poultry samples, the L. monocytogenes contamination level exceeded 1 CFU per g or cm2. Significant differences in pathogen contamination rates of poultry products were noticed between the poultry products originating from Belgian, French, and U.K. abattoirs. Poultry products derived from broiler chickens running free in pine woods until slaughtering age (12 to 13 weeks) had a significantly (P < 0.05) lower contamination rate of Salmonella than poultry products from enclosed broilers slaughtered at the age of 6 to 8 weeks. A significantly (P < 0.05) lower pathogen contamination rate was noted for Salmonella, C. jejuni, and C. coli for poultry cuts without skin compared to poultry cuts with skin on. An increase in pathogen contamination rate was noticed during cutting and further processing. To diminish C. jejuni, C. coli, Salmonella, and L. monocytogenes contamination rates, hygienic rules of slaughter and meat processing must be rigorously observed. At the moment, zero tolerance for these pathogens is not feasible, and there is a need to establish criteria allowing these pathogens to be present at reasonable levels in the examined poultry samples.     

Occurrence of multidrug resistance in Campylobacter from Ivorian poultry and analysis of bacterial response to acid shock

The level of antibiotic multiresistance of Campylobacter strains from chicken was evaluated and responses to the bactericidal effects of organic acids were analyzed. Strains (76) isolated from chicken were analyzed for resistance to antibiotics and acid shock. A high strain resistance to fluoroquinolones (ciprofloxacin and nalidixic acid) was observed, with cross resistance to both drugs in 41% of strains. A low resistance was observed for amoxicillin, erythromycin, and gentamicin. Campylobacter jejuni was the most resistant species. Antibacterial activities against multiresistant Campylobacter strains were observed using acetic, citric, and ascorbic acids at minimum bactericidal concentrations (MBC) ranging from 0.3 to 3 mg/mL. Acetic acid was the most efficient acid with the lowest MBC value. However, a contact time of 4 h was required for an efficient effect against Campylobacter contaminated chicken skin. Using organic acids in the poultry production chain can reduce propagation of antibiotic multiresistant strains of Campylobacter.     

The effects of Campylobacter numbers in caeca on the contamination of broiler carcasses with Campylobacter

For the presence and number of Campylobacter, 18 broiler flocks were sampled over a period of 18 months. A total of 70% of the flocks were positive for Campylobacter, with higher prevalence found in summer and autumn, compared to winter and spring. Positive flocks showed contamination rates above 90%, in negative flocks this was lower, mostly below 50%. The enumeration showed a decrease in Campylobacter during processing of positive flocks. The numbers were highest in carcasses after scalding/defeathering (mean 5.9 log(10) cfu/carcass) and dropped by 0.7 log(10) cfu/carcass after chilling. A positive correlation was observed between the number of Campylobacter present in the caeca and the number of bacteria present on carcasses and cut products. When a negative flock was slaughtered after Campylobacter positive flocks, the number of positive samples was higher compared to the case when a negative flock had been slaughtered previously. C. jejuni was isolated from 73.6% of the poultry samples.     

冰鲜家禽中弯曲菌检验的探讨

近年来发现弯曲菌与诸多疾病有关 ,因此 ,对食品中弯曲菌的检验越来越受到许多国家和部门的重视。在各类食品中 ,我们认为冰鲜家禽受弯曲菌污染的可能性较高 ,并从冰鲜家禽的皮肤、口腔、腹腔等部位分离出了结肠弯曲菌、海鸥弯曲菌和空肠弯曲菌。采用自动酶联免疫分析仪(Vidas)和Api快速筛选和鉴定 ,着重分析讨论了检测过程中遇到的多种问题。     

Distribution of Campylobacter spp. in selected U.S. poultry production and processing operations.

A study was conducted of 32 broiler flocks on eight different farms, belonging to four major U.S. producers. The farms were studied over I complete calendar year. Overall, 28 (87.5%) of the flocks became Campylobacter positive, and only four (12.5%) remained negative throughout the 6- to 8-week rearing period. In the majority of flocks, sampled every 2 weeks throughout production, Campylobacter-positive fecal and cecal samples were not detected until 4 to 8 weeks of age. In only six of the flocks were environmental samples found to be positive before shedding of Campylobacter was detected in the birds. Even in some of the Campylobacter-negative flocks, contamination of the rearing environment was positive for Campylobacter but did not result in the birds subsequently excreting the organism. These findings are discussed in relation to U.S. husbandry practices and present uncertainty about sources of Campylobacter infection for poultry flocks. Birds were often transported to the processing plant in coops that were already contaminated with Campylobacter, and the organisms were sometimes found in samples of scald water and chill water. After chilling, the proportions of Campylobacter-positive carcasses from different producers ranged from 21.0 to 40.9%, which is lower than in other studies, and possible reasons are considered.