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.

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 ؊7or 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 g/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 g/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.

Eastern North Carolina is a major contributor to both turkey and swine production in the United States. In this region, turkeys and swine are frequently grown in close proximity and by common growers. To further characterize colonization of turkeys and swine with Campylobacter in such a setting, we investigated the prevalence of thermophilic campylobacters in eight paired operations involving turkey farms in close proximity to finishing swine farms. All 15 surveyed flocks and 15 herds were Campylobacter positive at one or more sampling times. Campylobacter was isolated from 1,310 (87%) of the 1,512 turkey samples and 1,116 (77%) of the 1,448 swine samples. Most (> 99%) campylobacters from swine samples were Campylobacter coli, found in 59 to 97% of the samples from the different herds. Both Campylobacterjejuni and C. coli were recovered from the turkey flocks (overall prevalences of 52 and 35%, respectively). Prevalence among flocks ranged from 31 to 86% for C. jejuni and 0 to 67% for C. coli, and both species were recovered from most flocks. Relative prevalence of C. coli was higher in young birds (brooders), whereas C. jejuni predominated in grow-out birds (P < 0.0001). The prevalence of C. coli in a swine herd was generally not a good predictor for prevalence of this species in the corresponding turkey flock. These findings indicate that even though turkeys and swine grown in proximity to each other were commonly colonized with thermophilic campylobacters, the relative prevalences of C. jejuni and C. coli appear to be host associated.

Commercial turkey flocks in North Carolina have been found to be colonized frequently with Campylobacter coli strains that are resistant to several antimicrobials (tetracycline, streptomycin, erythromycin, kanamycin, and ciprofloxacin/nalidixic acid). Such strains have been designated multidrug resistant (MDR). However, the population structure of MDR C. coli from turkeys remains poorly characterized. In this study, an analysis of multilocus sequence typing (MLST)-based sequence types (STs) of 59 MDR strains from turkeys revealed that the majority of these strains corresponded to one of 14 different STs, with three STs accounting for 41 (69%) of the strains. The major STs were turkey specific, and most (87%) of the strains with these STs were resistant to the entire panel of antibiotics mentioned above. Some (13%) of the strains with these STs were susceptible to just one or two of the antibiotics in this panel. Further subtyping using fla typing and pulsed-field gel electrophoresis with SmaI and KpnI revealed that the major MDR STs corresponded to strains of related but distinct subtypes, providing evidence for genomic diversification within these STs. These findings suggest that MDR strains of C. coli from turkeys have a clonal population structure characterized by the presence of a relatively small number of clonal groups that appear to be disseminated in the turkey production system. In addition, the observed correlation between STs and the MDR profiles of the microbes indicates that MLST-based typing holds potential for source-tracking applications specific to the animal source (turkeys) and the antimicrobial resistance profile (MDR status) of C. coli.

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.

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 calorierestricted 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 fullfed 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. Cancer Prev Res; 4(4); 562-7. Ó2011 AACR.

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 ¼ 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 ¼ 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. Cancer Prev Res; 6(12); 1283-92. Ó2013 AACR.

Poult enteritis mortality syndrome (PEMS) is an economically devastating disease. To date, many questions about the syndrome remain unanswered, including its cause, transmission of causative agent(s), and control methods. Turkey coronavirus (TCV) infection has been associated with some outbreaks of PEMS, with areas having a higher prevalence of TCV infection also experiencing an increased incidence of PEMS. This study was designed to establish mortality patterns for flocks experiencing excess mortality and TCV infection in PEMS-affected regions and to delineate the possible role of TCV in PEMS-affected flocks. Fifty-four commercial turkey flocks on farms in areas with and without a history of TCV infection were monitored for weekly mortality and for antibodies to TCV. Flocks were chosen on the basis of placement dates and were monitored from day of placement until processing. All flocks were tested for TCV by an indirect fluorescent antibody assay. PEMS status was determined with the use of the clinical definition of mortality greater than 2% during any 3-wk period from 2 wk of age through the end of brooding due to unknown cause. Of the 54 flocks, 24 remained healthy, 23 experienced PEMS, and 7 tested positive for TCV but did not experience PEMS. Ten flocks experienced PEMS and tested positive for TCV, whereas 13 flocks experienced PEMS and did not test positive for TCV. Four health status groups were evident: healthy, PEMS positive, TCV positive, and PEMS + TCV positive. Distinct mortality patterns were seen for each of the four health status groups. Whereas TCV was associated with PEMS in 43% of PEMS cases, 13 cases (57%) of PEMS did not involve TCV. Additionally, 7 out of 17 cases of TCV (41%) did not experience excess mortality (PEMS) at any time during brooding of the flock. The results of this study indicate that TCV can be associated with PEMS but is neither necessary nor sufficient to cause PEMS.