Strain-Specific Differences in Survival of Campylobacter spp. in Naturally Contaminated Turkey Feces and Water.

Campylobacter jejuni and Campylobacter coli are leading causes of human foodborne illness, with poultry as a major vehicle. Turkeys are frequently colonized with Campylobacter, but little is known about Campylobacter survival in turkey feces, even though fecal droppings are major vehicles for Campylobacter within-flock transmission as well as for environmental dissemination. Our objective was to examine survival of Campylobacter, including different strains, in freshly excreted feces from naturally colonized commercial turkey flocks and in suspensions of turkey feces in water from the turkey house. Fecal and water suspensions were stored at 4°C, and Campylobacter populations were enumerated on selective media at 48-h intervals. C. jejuni and C. coli isolates were characterized for resistance to a panel of antibiotics, and a subset was subtyped using multilocus sequence typing. Campylobacter was recovered from feces and water for up to 16 days. Analysis of 548 isolates (218 C. jejuni and 330 C. coli) revealed that C. jejuni survived longer than C. coli in feces (P = 0.0005), while the reverse was observed in water (P < 0.0001). Strain-specific differences in survival were noted. Multidrug-resistant C. jejuni isolates of sequence type 1839 (ST-1839) and the related ST-2935 were among the longest-surviving isolates in feces, being recovered for up to 10 to 16 days, while multidrug-resistant C. coli isolates of ST-1101 were recovered from feces for only up to 4 days. Data on Campylobacter survival upon excretion from the birds can contribute to further understanding of the transmission dynamics of this pathogen in the poultry production ecosystem.IMPORTANCECampylobacter jejuni and Campylobacter coli are leading foodborne pathogens, with poultry as a major reservoir. Due to their growth requirements, these Campylobacter spp. may be unable to replicate once excreted by their avian hosts, but their survival in feces and the environment is critical for transmission in the farm ecosystem. Reducing the prevalence of Campylobacter-positive flocks can have major impacts in controlling both contamination of poultry products and environmental dissemination of the pathogens. However, understanding the capacity of these pathogens to survive in transmission-relevant vehicles such as feces and farmhouse water remains poorly understood, and little information is available on species- and strain-associated differences in survival. Here, we employed model conditions to investigate the survival of C. jejuni and C. coli from naturally colonized turkey flocks, and with diverse genotypes and antimicrobial resistance profiles, in turkey feces and in farmhouse water.

Emaciation and Sporadic Mortality in Older Laying Hens Caused by Intussusception of the Proventriculus.

Laying hens (n = 2267) ranging in age from 2 to 4 yr in a study evaluating ovarian cancer prevention were necropsied. Those that died or were culled during the 2-yr study (n = 1591) were necropsied weekly to determine the most probable cause of death or culling and cancer status. Hens surviving until the end of the study (n = 676) were euthanized and necropsied. Hens necropsied before and after a hen with proventricular intussusception served as cohorts (n = 38). Nineteen hens (13 dead, 6 culled) had intussusceptions of the proventriculus into the ventriculus. Mean age of affected hens was 154 wk (range 110-204 wk). None of the hens in the study had an intestinal intussusception, and none of the hens euthanized at the end of the study had a proventricular intussusception. Hens with proventricular intussusceptions were severely emaciated; mean body weights were 1040 and 1736 g for affected and cohort hens, respectively. Necropsy findings included prominent keel, marked muscle atrophy, generalized serous atrophy of fat, no visible proventriculus, esophagus directly entering the ventriculus, and an enlarged, spherical, firm ventriculus, which contained an invaginated, swollen, diffusely ulcerated proventriculus. Eighteen affected hens were anovulatory (94.7%) compared to 27 cohorts (71.1%). Severe, diffuse necrosis and ulceration of the proventricular mucosa was confirmed microscopically, but no etiologic agent was identified. In conclusion, proventricular intussusception of undetermined etiology was identified as a cause of sporadic emaciation, culling, and mortality in older laying hens.

Reporte de caso- Emaciación y mortalidad esporádica causadas por intususcepción del proventrículo en gallinas de postura maduras. Se realizaron necropsias de gallinas ponedoras (n=2267) de dos a cuatro años de edad en un estudio que evaluó la prevención del cáncer de ovario. Las aves que fueron eliminadas semanalmente durante el estudio de dos años (n=1591) se sometieron a la necropsia para determinar la causa más probable de muerte o de desecho y el estado de cáncer. Las gallinas que sobrevivieron hasta el final del estudio (n=676) se sacrificaron y se les realizó la necropsia. Las gallinas a las que se les practicó la necropsia antes y después de la intususcepción proventricular sirvieron como cohortes (n=38). Diecinueve gallinas (13 muertas y seis sacrificadas) tuvieron intususcepciones del proventrículo dentro de la molleja. La edad media de las gallinas afectadas fue de 154 semanas (con un rango de 110 a 204 semanas). Ninguna de las gallinas en el estudio mostró una intususcepción intestinal y ninguna de las gallinas sometidas a eutanasia al final del estudio tuvo una intususcepción proventricular. Las gallinas con intususcepciones proventriculares estaban severamente emaciadas; los pesos corporales medios fueron 1040 g y 1736 g para las gallinas afectadas y para las gallinas cohorte, respectivamente. Los hallazgos de la necropsia incluyeron la quilla de la pechuga prominente, atrofia muscular marcada, atrofia serosa de la grasa generalizada, no proventrículo visible, esófago entrando directamente en la molleja y una molleja esférica y firme, que contenía un proventrículo, invaginado, abultado y difusamente ulcerado. Dieciocho gallinas afectadas fueron anovulatorias (94.7%) en comparación con 27 cohortes (71.1%). La necrosis y la ulceración severas y generalizadas de la mucosa proventricular se confirmaron microscópicamente, pero no se identificó ningún agente etiológico. En conclusión, la intususcepción proventricular de etiología indeterminada se identificó como una causa de emaciación esporádica, sacrificio y mortalidad en gallinas ponedoras maduras.

Evidence of a chemopreventive effect of progestin unrelated to ovulation on reproductive tract cancers in the egg-laying hen.

Epidemiologic, laboratory, and animal evidence suggests that progestins and vitamin D may be potent ovarian cancer preventives. Our objectives were to evaluate progestins as reproductive tract cancer chemopreventives in the chicken, determine whether restricted ovulation affected the incidence of reproductive tract tumors, and assess whether vitamin D would confer cancer protection either alone or in addition to progestin. A total of 2,400 two-year-old Single Comb White Leghorns were randomized into six groups (400 each) with hormonal and dietary manipulation for 2 years as follows: (i) no intervention, regular feed/caloric intake, (ii) control, (iii) vitamin D, (iv) the progestin levonorgestrel, (v) vitamin D plus levonorgestrel, and (vi) the progestin Provera (medroxyprogesterone acetate). Groups 2 to 6 were caloric restricted to inhibit ovulation. Our results indicated that caloric restriction decreased egg production by more than 60%, and was associated with a greater than 70% decrease in reproductive tract cancers. Ovulatory events did not differ among the caloric-restricted groups (groups 2-6), except for the group receiving levonorgestrel, which had fewer ovulatory events than controls (P = 0.046). After correcting for egg production, birds receiving progestins had significantly fewer reproductive tract cancers [OR, 0.61; confidence interval (CI), 0.39-0.95; P = 0.03], with similar proportionate reductions in tumors arising in either the ovary or oviduct. Vitamin D did not significantly affect cancer incidence overall, or add to the cancer preventive effect of progestins. This study suggests a protective effect of progestins against ovarian and oviductal cancers. These data support the concept that progestins provide a chemopreventive effect unrelated to ovulation.

Reduction of ovarian and oviductal cancers in calorie-restricted laying chickens.

Epithelial ovarian cancer (OVAC) remains a highly lethal malignancy. It is a leading cause of cancer deaths among women in the United States causing more deaths than all other gynecologic malignancies combined. The pathogenesis of OVAC is not completely understood, but the process of repeated ovulation is believed to lead to genetic damage in the ovarian epithelium. As part of a prospective trial designed to evaluate OVAC chemopreventive strategies using the chicken model, caloric restriction (55% less energy) was used to inhibit ovulation in groups of hens receiving chemopreventives, thereby minimizing the impact of ovulation on the incidence of reproductive tract cancer. A separate group of chickens was maintained concurrently in the same environment, and managed similarly, except that caloric intake was not restricted. Among birds not receiving chemopreventive agents, we compared caloric versus noncaloric restricted birds to determine the relations between calorie restriction and risk of developing adenocarcinoma of the reproductive tract. Mortality in the calorie-restricted group was almost half that of those on full feed. Calorie-restricted chickens maintained body weights averaging 1.423 kg compared with the full-fed birds at 1.892 kg. Ovulation rate varied with the full-fed group producing 64% more eggs than the calorie-restricted group. Total reproductive cancers occurred in 57 (33.3%) birds for the full-fed group and 26 (10.3%) birds for the calorie-restricted group. On the basis of histopathology, 45 (26.3%) birds in the full-fed group had ovarian adenocarcinoma compared with 16 (6.3%) birds in the calorie-restricted group. Calorie restriction in laying hens resulted in a near five-fold reduction in OVAC.

Ovarian adenocarcinomas in the laying hen and women share similar alterations in p53, ras, and HER-2/neu.

We examined alterations in the p53 tumor suppressor gene and the ras and HER-2/neu oncogenes in chicken ovarian cancers to determine if these tumors have genetic alterations similar to those in human ovarian adenocarcinomas. Mutations in the p53 tumor suppressor gene and the H-ras and K-ras oncogenes were assessed by direct sequencing in 172 ovarian cancers obtained from 4-year-old birds enrolled at age 2 in two separate 2-year chemoprevention trials. Birds in trial B had approximately twice as many lifetime ovulations as those in trial A. Immunohistochemical staining for the HER-2/neu oncogene was done on a subset of avian ovarian and oviductal adenocarcinomas. Alterations in p53 were detected in 48% of chicken ovarian cancers. Incidence of p53 alterations varied according to the number of lifetime ovulations, ranging from 14% in trial A to 96% in trial B (P < 0.01). No mutations were seen in H-ras, and only 2 of 172 (1.2%) tumors had K-ras mutations. Significant HER-2/neu staining was noted in 10 of 19 ovarian adenocarcinomas but in only 1 of 17 oviductal adenocarcinomas. Similar to human ovarian cancers, p53 alterations are common in chicken ovarian adenocarcinomas and correlate with the number of lifetime ovulations. Ras mutations are rare, similar to high-grade human ovarian cancers. HER-2/neu overexpression is common and may represent a marker to exclude an oviductal origin in cancers involving both the ovary and oviduct.

Natural transformation-mediated transfer of erythromycin resistance in Campylobacter coli strains from turkeys and swine.

Erythromycin resistance in Campylobacter coli from meat animals is frequently encountered and could represent a substantial barrier to antibiotic treatment of human infections. Erythromycin resistance in this organism has been associated with a point mutation (A2075G) in the 23S rRNA gene. However, the mechanisms responsible for possible dissemination of erythromycin resistance in C. coli remain poorly understood. In this study, we investigated transformation-mediated acquisition of erythromycin resistance by genotypically diverse C. coli strains from turkeys and swine, with total genomic DNA from erythromycin-resistant C. coli of either turkey or swine origin used as a donor. Overall, transformation to erythromycin resistance was significantly more frequent in C. coli strains from turkeys than in swine-derived strains (P < 0.01). The frequency of transformation to erythromycin resistance was 10(-5) to 10(-6) for turkey-derived strains but 10(-7) or less for C. coli from swine. Transformants harbored the point mutation A2075G in the 23S rRNA gene, as did the erythromycin-resistant strains used as DNA donors. Erythromycin resistance was stable in transformants following serial transfers in the absence of the antibiotic, and most transformants had high MICs (>256 microg/ml), as did the C. coli donor strains. In contrast to the results obtained with transformation, spontaneous mutants had relatively low erythromycin MICs (32 to 64 microg/ml) and lacked the A2075G mutation in the 23S rRNA gene. These findings suggest that natural transformation has the potential to contribute to the dissemination of high-level resistance to erythromycin among C. coli strains colonizing meat animals.

Strain persistence and fluctuation of multiple-antibiotic resistant Campylobacter coli colonizing turkeys over successive production cycles.

The dynamics of colonization of turkeys by thermophilic campylobacters that are resistant to multiple antibiotics is poorly understood. In this study, we monitored cecal colonization of turkeys by Campylobacter over three successive production cycles at the same farm. Campylobacter isolated from the ceca was predominantly C. coli in all three flocks. Isolates with two distinct fla types that represented a single clonal group based on pulsed-field gel electrophoresis and that were resistant to multiple antibiotics (tetracycline, streptomycin, ampicillin, erythromycin, kanamycin, nalidixic acid, and ciprofloxacin) predominated throughout the three production cycles. The relative prevalence of each fla type, however, varied significantly from one flock to the next. The repeated isolation of these multiresistant C. coli from successive flocks likely reflected persistence of the organisms in currently unknown reservoirs in the production environment or, alternatively, repeated introduction events followed by establishment of these bacteria in each successive flock.

Risk factors associated with poult enteritis mortality syndrome-positive turkey flocks.

Poult enteritis mortality syndrome (PEMS) has been an economically devastating disease in North Carolina since the early 1990s. Though much is known about the disease, many questions remain unanswered about the syndrome, including its cause, transmission of causative agent(s), and control methods. This study was designed to investigate the association between PEMS and farm management factors. A prospective longitudinal study was conducted by collecting farm data and monitoring weekly mortality in 54 commercial turkey flocks raised in PEMS-affected regions. Univariate and multivariate statistical analyses revealed that enhancing rodent control methods was negatively associated (P = 0.0228) with PEMS.