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1.
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.  相似文献   

2.
An action plan against thermophilic Campylobacter spp. in Norwegian broilers was implemented in May 2001. The action plan consists of three parts: a surveillance program including all Norwegian broiler flocks slaughtered before 50 days of age, a follow-up advisory service on farms delivering flocks positive for Campylobacter spp., and surveys of broiler meat products at the retail level. This article presents results covering the inclusive 3-year period between 2002 and 2004. During this period, a total of 10,803 flocks from 562 broiler farms were tested; altogether, 521 (4.8%) of the flocks were identified as positive for Campylobacter spp., primarily Campylobacter jejuni. The positive flocks originated from 257 (45.7%) of the farms. During the period 2002 to 2004, there was a large and steady reduction in flock prevalence, from 6.3% in 2002 to 3.3% in 2004. Also, the proportion of farms producing flocks positive for Campylobacter spp. each year reduced substantially, from 28.4% in 2002 to 17.8% in 2004. The proportion of flocks positive for Campylobacter spp. varied considerably with season and region. The action plan is a successful collaboration between academia, regulatory agencies, and the poultry industry that has resulted in a significant reduction in the number of broiler carcasses positive for Campylobacter spp. on the market. The temporal associations between implementation of the control program and the drop in the number of infected chickens and contaminated carcasses indicate that this collaborative action plan has been instrumental in achieving the goals of enhancing food safety.  相似文献   

3.
Campylobacter spp. cause numerous foodborne diseases. Poultry is thought to be a significant source of this zoonosis. Although many interventions designed to control this agent have been researched, none have succeeded. We evaluated a bacteriocin-based treatment to reduce Campylobacter jejuni colonization in poultry. A previously described purified bacteriocin (class IIa; molecular mass, 3,864 Da), secreted by Paenibacillus polymyxa NRRL-B-30509, was microencapsulated in polyvinylpyrrolidone, and 0.25 g of the purified bacteriocin was incorporated into 1 kg of chicken feed. One-day-old chickens were orally challenged and colonized with one of four isolates of C. jejuni, then reared in isolation facilities. Birds were provided ad libitum access to standard broiler starter feed and water for 7 days until 3 days before sampling, when only the treated groups of birds were provided the bacteriocin-emended feed described. In each of the eight (four by two replicates) trials, significant reductions in colonization by C. jejuni were observed (P < or = 0.05). As an example of this highly consistent data, in the first trial, 10 untreated 10-day-old chickens were colonized at a mean log 7.2 + 0.3 CFU/g of feces, whereas none of the 10 bacteriocin-treated 10-day-old chickens were colonized with detectable numbers of C. jejuni. Bacteriocin treatment dramatically reduced both intestinal levels and frequency of chicken colonization by C. jejuni. Feeding bacteriocins before poultry slaughter appears to provide control of C. jejuni to effectively reduce human exposure. This advance is directed toward on-farm control of pathogens, as opposed to the currently used chemical disinfection of contaminated carcasses.  相似文献   

4.
Campylobacter bacteria are important foodborne pathogens that cause acute diarrheal illness, and infection is often associated with contaminated poultry. In a blind observational study, the prevalence and resistance profiles of thermophilic Campylobacter strains collected from different poultry production systems were tested against the clinically used antibiotics ciprofloxacin, tetracycline, erythromycin, gentamicin, and streptomycin. Campylobacter strains were isolated from chickens in rural production systems, a free-range commercial facility, and industrially raised broiler and egg-laying chickens all situated in KwaZulu-Natal, South Africa. Isolates were collected from the chicken cecae and were identified with conventional methods and tested for antibiotic resistance with the Clinical and Laboratory Standards Institute agar dilution method. The prevalence of Campylobacter spp. isolates in chickens was 68% (56 samples) in rural production, 47% (140 samples) in commercial free-range broilers, 47% (133 samples) in industrial broilers, and 94% (34 samples) in industrial layer hens. Isolates from the rurally raised chickens showed significantly (P < 0.01) less resistance against ciprofloxacin (7.9%), erythromycin (0%), and tetracycline (21.6%) than those from commercially produced chickens. Isolates from the commercially raised chickens (free range and industrial) were highly resistant to tetracycline (98.9 to 100%). The incidence of gentamicin and streptomycin resistance was 1.6 and 11.5%, respectively, in commercial free-range broilers, 1.7 and 16.4%, respectively, in industrially raised broilers, and 12.9 and 40%, respectively, in industrially raised layers. It is possible that variations among the poultry production systems, including antimicrobial usage, result in differences in antibiotic resistance profiles in Campylobacter.  相似文献   

5.
Human campylobacteriosis has become the major cause of foodborne gastroenteritis in industrialized countries. Although there have been numerous studies investigating the prevalence of Campylobacter in animals and raw meat, sensitive and low-cost detection methods are needed to implement effective control measures during primary production and to use as tools in risk assessment studies. Thermophilic Campylobacter spp. in naturally contaminated (n = 64) and inoculated (n = 16) broiler samples were detected using two International Organization for Standardization (ISO)-approved methods. Both enrichment broths (those of Preston and of Park and Sanders) were inoculated with (i) Campylobacter jejuni ATCC35921, (ii) boneless breast from broilers, (iii) boneless breast rinse solution, (iv) boneless breast rinse solution inoculated with C. jejuni ATCC35921 before centrifugation, and (v) boneless breast rinse solution inoculated with C. jejuni ATCC35921 after centrifugation. The results indicated that the Park and Sanders broth was superior to the Preston broth for recovery of Campylobacter spp., and no significant differences (P > 0.05) were found between ISO (meat pieces) and modified ISO (centrifuged chicken rinse solution) methods for the detection of Campylobacter spp.  相似文献   

6.
Antimicrobial susceptibility in Campylobacter jejuni collected from the environment outside four broiler houses (n = 63) and from the environment inside these broiler houses (including broiler droppings) (n = 36) from May to September 2004 was studied and compared with isolates from Norwegian broilers analyzed within the frame of the Norwegian monitoring program of antimicrobial resistance in feed, food, and animals (NORM-VET) in 2004 (n = 75). The MICs of oxytetracycline, ampicillin, erythromycin, gentamicin, enrofloxacin, and nalidixic acid were obtained by the broth microdilution method VetMIC. The present study, which to our knowledge is the first Norwegian study on the occurrence of antimicrobial resistance in Campylobacter spp. from the environment of broiler houses, revealed a very low occurrence of antimicrobial resistance in C. jejuni from the broilers and broiler house environments studied. All isolates originating from the four broiler houses studied were susceptible to all the antimicrobial agents tested, except for one isolate from the outdoor environment (courtyard soil), which was resistant to oxytetracycline (MIC, 8 mg/liter). For the isolates from broilers (NORM-VET), low prevalences of resistance to oxytetracycline (1.3%) and ampicillin (4%) were observed. No quinolone resistance was observed. The results for the broiler isolates are in agreement with the earlier findings of a very low prevalence of resistance in Campylobacter from broilers in Norway, which reflects the low usage of antimicrobials in Norwegian broiler production. Furthermore, the present data are in accordance with antimicrobial susceptibility data for C. jejuni from domestically acquired human cases.  相似文献   

7.
Of 509 samples from poultry flocks, 209 isolates (41.1%) were Campylobacter positive. The number of positive cases in broiler carcasses was 45.9%. Of 52 pheasants investigated, 25.9% were Campylobacter positive. Campylobacter jejuni was isolated from 86 (42.0%) poultry flock samples, 47 (43%) broiler samples and 15 (28%) wild pheasant samples. C. coli was found at a rate of 1.2% in poultry flocks, 13% in broilers and 21% in pheasants.  相似文献   

8.
To determine the source of food contamination with Campylobacter jejuni, we investigated retail meat, a chicken processing plant and a broiler farm. C. jejuni was found in domestic retailed poultry (45.8%) and imported poultry (3.7%), but not in beef or pork. In the poultry processing plant, there is significant contamination with C. jejuni in chicken carcasses, equipment and workers' hands. This contamination increases during the defeathering and evisceration processes. RAPD analysis shows that contamination with C. jejuni is of intestinal origin. In a broiler farm, C. jejuni was first isolated from a faecal sample of broiler chicken after the 20th day of age. Two weeks later, all birds in this farm became C. jejuni positive. RAPD analysis indicated that C. jejuni spread rapidly from one broiler flock to the other flocks on the farm.  相似文献   

9.
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%).  相似文献   

10.
Campylobacter jejuni is the most common bacterial cause of diarrheal disease in humans worldwide, with poultry products being a major source. Therefore, strategies to decrease Campylobacter colonization during primary production might aid in reducing the number of human campylobacteriosis cases. Several plant-derived compounds have been reported to possess anti-Campylobacter properties in vitro, so they could be promising candidates to reduce Campylobacter colonization in broiler chickens. To test this hypothesis, selected plant-derived antimicrobials (caffeic, gallic, protocatechuic, and vanillic acids, epigallocatechin gallate, trans-cinnamaldehyde, and thymol) were screened for anti-Campylobacter activity by determining MICs and setting up time-kill curves for C. jejuni strain KC 40. These experiments revealed marked antibacterial activity, especially for the cinnamon oil ingredient trans-cinnamaldehyde (CIN). This compound was tested in a broiler chick seeder model; it was added to the feed in coated form at an effective concentration of 0.3 % from day-of-hatch for the entire 22-day duration of the experiment. At 14 days of age, one-third of the birds were inoculated with C. jejuni strain KC 40 and served as seeders. CIN was not able to reduce cecal Campylobacter colonization in this model, which was confirmed in a cecal loop experiment. Despite CIN concentrations much higher than the MIC, C. jejuni numbers were not reduced compared with those in nontreated ceca at 2 and 24 h after injection. In conclusion, this study shows a marked discrepancy between in vitro and in vivo activity of CIN against C. jejuni strain KC 40.  相似文献   

11.
Between July 1998 and June 1999, 93 lots of broiler chickens distributed on 57 farms were sampled in two abattoirs of the province of Quebec (Canada). A total of 2,325 samples of cecal material were analyzed to determine the prevalence of campylobacters. Biotyping and pulsed-field gel electrophoresis (PFGE) were done on 20% of the Campylobacter isolates to study the distribution within poultry production. Macrorestriction profiles were compared with profiles of 24 Campylobacter strains isolated from sporadic cases of human diarrheic patients in order to evaluate genetic relationships. Approximately 40% of the broiler chickens in 60% of the lots and 67% of the farms were colonized. Biotypes I and II of Campylobacter jejuni were the most prevalent biotypes in poultry and human isolates. The PFGE dendograms revealed a high genetic diversity among poultry isolates, with 49 different genotypes from the 56 positive lots. More than 75% of these lots were colonized by a unique genotype. All positive lots raised simultaneously on the same farm had common genotype(s). Different genotypes were isolated from lots raised at different grow-out periods on a farm. In some cases, identical genotypes were found at different grow-out periods on a farm and also from different farms. Macrorestriction profiles showed that approximately 20% of human Campylobacter isolates were genetically related to genotypes found in poultry. This genetic relationship and the high prevalence of C. jejuni biotypes I and II in poultry indicated that Campylobacter in broiler production of the province of Quebec could be a potential source of hazard for public health.  相似文献   

12.
The occurrence of metronidazole resistance was investigated among Campylobacter jejuni in raw poultry meat collected from supermarkets. MICs were determined by the agar dilution procedure in the testing range of 3 to 60 microg/ml metronidazole. The MICs showed a bimodal distribution with a significant proportion of metronidazole-resistant isolates among C. jejuni from raw broiler and turkey meat. Metronidazole resistance occurred most frequently among turkey meat isolates (P < 0.005). This is the first report of foodborne bacteria carrying metronidazole resistance.  相似文献   

13.
Genetic variations in Campylobacter jejuni or host factors result in low prevalence rates among nonchicken poultry species. The objective of this study was to determine the colonizing potential, in broiler chickens, of C. jejuni that was recovered from low-prevalence avian species. Twenty-day-old Campylobacter-negative broiler chicks were inoculated by oral gavage with genetically different primary isolates of C. jejuni recovered from squab, duck, or chicken. Serial sampling and microbiologic testing of ceca were used to determine the level of colonization and the prevalence of positive chickens. All isolates were recovered from chickens by 10 days postinoculation. The C. jejuni strains recovered from challenged birds were genetically identical to the inoculated strains. By 10 days postinoculation, treatment groups inoculated with duck or control chicken isolates were 100% positive. The level of colonization by the squab isolate on day 2 postinoculation was significantly less than the duck or chicken isolates and had not colonized all birds by day 10 postinoculation.  相似文献   

14.
The presence of Campylobacter spp. on broiler carcasses and in scald water taken from a commercial poultry processing facility was monitored on a monthly basis from January through June. Campylobacter agar, Blaser, was used to enumerate Campylobacter in water samples from a multiple-tank scalder; on prescalded, picked, eviscerated, and chilled carcasses; and on processed carcasses stored at 4 degrees C for 7 or 14 days. The MIDI Sherlock microbial identification system was used to identify Campylobacter-like isolates based on the fatty acid methyl ester profile of the bacteria. The dendrogram program of the Sherlock microbial identification system was used to compare the fatty acid methyl ester profiles of the bacteria and determine the degree of relatedness between the isolates. Findings indicated that no Campylobacter were recovered from carcasses or scald tank water samples collected in January or February, but the pathogen was recovered from samples collected in March, April, May, and June. Processing generally produced a significant (P < 0.05) decrease in the number of Campylobacter recovered from broiler carcasses, and the number of Campylobacter recovered from refrigerated carcasses generally decreased during storage. Significantly (P < 0.05) fewer Campylobacter were recovered from the final tank of the multiple-tank scald system than from the first tank. MIDI similarity index values ranged from 0.104 to 0.928 based on MIDI-fatty acid methyl ester analysis of Campylobacterjejuni and Campylobacter coli isolates. Dendrograms of the fatty acid methyl ester profile of the isolates indicated that poultry flocks may introduce several strains of C. jejuni and C. coli into processing plants. Different populations of the pathogen may be carried into the processing plant by successive broiler flocks, and the same Campylobacter strain may be recovered from different poultry processing operations. However, Campylobacter apparently is unable to colonize equipment in the processing facility and contaminate broilers from flocks processed at later dates in the facility.  相似文献   

15.
The objective of this study was to isolate from chickens potential competitive exclusion bacteria (CE) that are inhibitory to Campylobacter jejuni or Salmonella, or to both, for subsequent development of a defined CE product for use in poultry. Adult chickens from family farms, commercial farms, and broiler chicken research centers were sampled to identify and select C. jejuni-free donor chickens. A challenge treatment, which included administering perorally 106 CFU C. jejuni per chicken and determining undetectable cecal shedding of campylobacters at 4 weeks, was important for identifying the best CE donor chickens. Screening of bacterial colonies obtained from nine donor chickens by using selective and nonselective media yielded 636 isolates inhibitory to six C. jejuni strains in vitro, with 194 isolates being strongly inhibitory. Of the 194 isolates, 145 were from ceca, and 117 were facultative anaerobic bacteria. One hundred forty-three isolates were inhibitory to six strains of Salmonella (including five different serotypes) in vitro. Of these, 41 were strongly inhibitory to all C. jejuni and Salmonella strains evaluated, and most were Lactobacillus salivarius. A direct overlay method, which involved directly applying soft agar on plates with discrete colonies from mucus scrapings of gastrointestinal tracts, was more effective in isolating CE than was the frequently practiced isolation method of picking and transferring discrete colonies and then overlaying them with soft agar. The best approach for obtaining bacteria highly inhibitory to Salmonella and C. jejuni from chickens was to isolate bacteria from ceca under anaerobic conditions. Free-range chickens from family farms were better donors of potential CE strongly inhibitory to both Salmonella and Campylobacter than were chickens from commercial farms and broiler chicken research centers.  相似文献   

16.
通过在肉鸡饲料中添加不同剂量的苦杏仁粉,评价其对肉鸡生长性能、肉品质及肝脏抗氧化能力的影响,探究苦杏仁在畜禽生产中应用及最适添加量,为饲料中抗营养因子的开发利用提供试验依据。试验将100只1日龄AA肉鸡,随机分为4组,每组25只;对照组(C组)饲喂基础全价饲料,低剂量组(L组)饲喂含4.5 g/kg苦杏仁粉的基础全价饲料,中剂量组(M组)饲喂含9 g/kg苦杏仁粉的基础全价饲料,高剂量组(H组)饲喂含17 g/kg苦杏仁粉的基础全价饲料,试验周期为45 d。结果表明,与C组相比,H组肉鸡的终末体重和平均日增重极显著降低(P<0.01),料重比极显著升高(P<0.01),而L组、M组肉鸡的末体重和平均日增重及料重比无显著差异(P>0.05);肌肉放置24 h和48 h后,H组肌肉肉色显著降低(P<0.05),肌肉剪切力极显著增加(P<0.01);L组胸肌粗蛋白质含量显著升高(P<0.05),M组、L组差异不显著(P>0.05)。饲料中添加不同剂量的苦杏仁粉均增强肉鸡肝脏中SOD、CAT和GSH-PX的活性(P<0.05)。试验说明,饲料中添加的低剂量(4.5 g/kg)和中剂量(9 g/kg)苦杏仁粉均可改善肉鸡肉品质和增强肝脏抗氧化性能,其中以添加9 g/kg苦杏仁的效果最佳。而添加高剂量(17 g/kg)的苦杏仁粉虽能增强肉鸡肝脏的抗氧化能力,但会导致肉鸡的生长性能和肉品质降低。  相似文献   

17.
Thermotolerant Campylobacter jejuni and C. coli are one of the major causes of bacterial foodborne enteric infection. Consuming and/or handling poultry meat is the most consistent risk factor, linked to the high prevalence of campylobacters in retail poultry meat. The aim of the present study was to ascertain the genetic diversity and/or possible specificity of thermotolerant Campylobacter isolates according to species (C. coli, C. jejuni), isolation source (retail chicken meat and human clinical samples) and geographic origin (Goriska in Slovenia and Zenica-Doboj Canton in Bosnia and Herzegovina (BIH)). With the pulsed-field gel electrophoresis (PFGE) after SmaI macrorestriction we distinguished 80 PFGE types among 118 strains and CfoI restriction fragment length polymorphism of the amplified flagellin gene (fla-RFLP) gave 12 fla-RFLP types. Beside the higher discriminatory power and strain typeability, PFGE discriminated the C. jejuni and C. coli groups of isolates. A high proportion of C. coli strains was isolated, especially from poultry samples. Identical or very similar PFGE types among the isolates from animal, food and human samples indicate the transmission of C. jejuni and C. coli from the chickens on the farm to the retail chicken meat, as well as possible cross-contamination of retail meat and transmission to humans. However, the identity of the isolates from non-related samples but with identical PFGE and fla-RFLP types should be confirmed with additional typing. Reliable tracing of the source of Campylobacter strains by molecular typing of the chicken meat isolates is therefore very difficult. The reasons include contamination of meat samples with multiple strains, possible cross-contamination and extreme heterogeneity of the isolates (mainly for C. jejuni) on one side and a limited power of the genotyping methods used to distinguish non-related strains on the other side (mainly for C. coli).  相似文献   

18.
Campylobacter jejuni is a frequently detected food-borne pathogenic bacterium. Clinical cases are mostly sporadic but campylobacteriosis can have serious consequences, such as the development of Guillain-Barré syndrome as well as diarrheal diseases. We examined 265 retail raw chickens from Korean markets for the presence of C. jejuni using the US Food and Drug Administration standard cultural method and multiplex polymerase chain reaction (mPCR). The mPCR-confirmed C. jejuni isolates were subtyped by pulsed field gel electrophoresis (PFGE) and flaA-typing for investigating the genetic diversity of the microorganism in retail raw chickens. Restriction enzymes SmaI and DdeI were used for PFGE and flaA-typing, respectively. Campylobacter spp. were found in 181 samples (68.3%) and C. jejuni in 100 samples (37.74%). For C. jejuni, 73 pulsotypes and 30 flaA types were detected. Antibiotic resistance tests performed by disk diffusion assay indicated that most C. jejuni isolates were resistant to tetracycline, nalidixic acid, and ciprofloxacin, and 87 composite types were revealed by PFGE, flaA-typing, and the antibiotic resistance tests. Our results show that the genetic diversity of C. jejuni isolates is very high and the correlation between genotype and antibiotic resistance was low even though many bacteria showed multi-drug resistance.  相似文献   

19.
In this study, the conventional International Organization for Standardization (ISO) culture method was compared with the DuPont Qualicon BAX system, a high-throughput, rapid molecular assay that can be used to detect several bacterial species, including Campylobacter jejuni and Campylobacter coli in diverse sample types. Standard enrichment culture is a time-consuming process, taking up to 6 days to obtain a confirmed result. Rapid molecular assays have been developed that provide results within 24 h. Naturally contaminated samples from the poultry production chain were examined for the presence of Campylobacter spp. Samples from broiler chicken ceca (n = 100), fresh chicken carcass rinses (n = 60), and bootsocks (gauze sock walked through a broiler chicken house; n = 50) were enriched according to the ISO 10272 method in Bolton broth specifically designed to detect Campylobacter spp. in complex sample types. Samples were enriched without blood for use with the BAX system using the Campylobacter BAX kits for the detection of C. jejuni and C. coli. Samples also were directly plated onto modified charcoal cefperazone deoxycholate agar, and results were compared with those from the enriched samples for the ability to detect Campylobacter spp. Campylobacter spp. were isolated from 49% of samples with conventional enrichment cultures, from 48% with direct culture, from 68% with the BAX system and enrichment cultures, and from 62% with the BAX system used directly with samples. Overall, the BAX system detected more positive samples than did the conventional culture method and is an effective methodology for the rapid and reliable detection of Campylobacter spp. from diverse sample types.  相似文献   

20.
On 15 Swiss poultry farms, broiler flocks, other farm animals, and the environment were examined during consecutive rearing periods to investigate the occurrence and genetic diversity of Campylobacter. Of the 5154 collected samples, 311 (6%) from 14 farms were Campylobacter positive by culture. Amongst the positive samples, 228 tested positive for Campylobacter jejuni and 92 for Campylobacter coli. Positive samples originated from broilers, the broiler houses, cattle, pigs, bantams, laying hens, a horse, and a mouse. Feed, litter, flies, and the supply air to the broiler house tested negative. By flagellin gene typing (fla-RFLP) and pulsed-field gel electrophoresis (PFGE), 917 Campylobacter isolates were genotyped. Additionally, amplified fragment length polymorphism (AFLP) analysis was performed on 15 assorted strains. On eight farms, matching genotypes were isolated from broiler flocks and other farm animals: Certain genotypes from cattle (farms H, K, L, and M), pigs (farms D and P), or laying hens (farm L) were subsequently found in the broiler flocks, whereas other genotypes initially present in the broiler flocks turned up in cattle (farms A, D, and O). These results emphasize the importance of other farm animals on poultry farms for broiler flock colonization. Indications of persistent contamination of the broiler house were evident on four farms (C, D, I, and L) where matching genotypes were detected in consecutive broiler flocks, but not concurrently in other samples. By fla-RFLP, PFGE, and confirmed by AFLP, some genotypes proofed to be identical across different farms.  相似文献   

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