Response of restraint stress-selected lines of Japanese quail to heat stress and Escherichia coli challenge

Japanese quail selected for divergent corticosterone response to restraint stress were evaluated for their susceptibility to heat stress and challenge with Escherichia coli. These quail lines are designated as high stress (HS), low stress (LS), and the random-bred control (CS) lines. Heat stress (35°C, 8 h/d) began at 24 d until the end of the study at 39 d. Birds were challenged with an aerosol spray containing 2 × 10(9) cfu of E. coli at 25 and 32 d. At 38 d, the surviving birds were necropsied and the intestinal tract was screened for both Salmonella and Campylobacter. Body weights of the CS birds were higher than both HS and LS at 17, 25, and 32 d. At 32 d, there was no difference in mortality between males and females and the CS line had higher mortality compared with the LS line with the HS line being intermediate. At 38 d, females of the CS line that were both heat stressed and challenged had a mortality incidence of 25%, which was significantly higher than male birds of the same line and treatment (5.3%). There was an increased incidence in Salmonella enterica serotype Agona isolation after heat stress, with the LS birds having less isolation than the HS birds. Mean corticosterone levels of male birds were not significantly affected by line, heat stress, or E. coli challenge; however, the LS line subjected to heat stress had one-third the level of the HS line, a difference identical to that seen in the original selection for response to restraint stress.

Yeast cell-wall products containing beta-glucan plus ascorbic acid affect neonatal Bos taurus calf leukocytes and growth after a transport stressor

The objectives were to ascertain whether a yeast cell-wall derivative that was 1.8% beta-glucan in combination with ascorbyl-2-polyphosphate could improve innate immunity and mediate transportation stress in neonatal calves, and to compare the 1.8% beta-glucan yeast cell-wall derivative with a more purified yeast cell-wall derivative (70% beta-glucan). Treatments were 1) an unsupplemented control (CNT); 2) 113 g of a 1.8% (approximately 2%) beta-glucan derivative of yeast cell walls plus 250 mg of l-ascorbic acid phosphate (BG2); or 3) 150 mg of a purified beta-glucan fraction from yeast cell walls (approximately 70% beta-glucan) plus 250 mg/feeding of l-ascorbic acid phosphate (BG70). Calves (n = 39) were transported for 4 h, placed in outdoor hutches, and randomly assigned to treatments. Treatments (mixed with a milk replacer) were individually fed twice daily for 28 d. Calves were offered calf starter, free choice, throughout the study. Weekly starter intake and BW were measured, and fecal samples were collected for Salmonella Typhimurium and Escherichia coli O157:H7 PCR analysis. Blood was collected immediately before transport (d 0) and on d 3, 7, 10, 14, 21, and 28 after transport. Starter intake and DMI were less (P < 0.05) at d 28 for the BG2 and BG70 treatments compared with the CNT treatment. Hematocrit percentages increased (P = 0.002) throughout the experiment. White blood cell counts (treatment x time interaction, P = 0.066) were less for the calves supplemented with BG70 than for those supplemented with BG2 (P = 0.01) or for CNT calves (P = 0.04) on d 28. Granulocyte counts changed (P = 0.04) throughout the experiment. A trend (P = 0.077) for a treatment x time interaction was detected for peripheral blood mononuclear cell counts (PBMC). Counts of PBMC were greater (P = 0.006) for the BG2 treatment compared with the CNT treatment on d 3. Calves given the BG70 supplement had fewer PBMC than those given the BG2 supplement on d 21 (P = 0.03) and 28 (P = 0.05). Fibrinogen concentrations were affected only by time (P = 0.002). Time effects were detected for phagocytosis (P = 0.005), oxidative burst (P < 0.001), expression of cluster of differentiation 18 (P = 0.001), and increased cluster of differentiation 18 (P = 0.006). Phagocytosis was less (P = 0.05) for calves in the BG70 group than for those in the CNT group. Percentage of calves positive for E. coli O157:H7 was greatest (P <or= 0.05) for those in the BG2 group on d 7 compared with those in the other treatments. The BG2 and BG70 supplements both increased feed intake, but only the BG2 supplement increased E. coli shedding on d 7, and the BG2 and BG70 supplements varied in modulating immune functions, indicating differences in yeast extract function.

Comparison of DNA extraction methods for analysis of turkey cecal microbiota

AIM

As a prelude to long-term studies to characterize the microbiota of the turkey ceca, 14 DNA isolation protocols were evaluated for their ability to reproducibly characterize microbial diversity.

METHODS AND RESULTS

Eight commercially available DNA extraction kits were assessed. DNA quantity and quality were assessed and competitive PCR was used to quantify the 16S bacterial rRNA genes. The Invitrogen Easy-DNA Kit extraction method for large samples yielded over eight times more DNA than any other method (3144 +/- 873 microg g(-1) of sample, P < 0.05). Bacterial and fungal species richness was estimated by Automated Ribosomal Intergenic Spacer Analysis. The Invitrogen Easy-DNA Kit generated the greatest bacterial species richness (46 +/- 7 peaks) while Bio-Rad Aquapure yielded the highest fungal species richness (71 +/- 9.5 peaks).

CONCLUSION

Cluster analysis indicated different DNA extraction methods generated different microbial community compositions using the same cecal matrix from a single donor bird.

SIGNIFICANCE AND IMPACT OF THE STUDY

Optimized DNA extraction protocols Invitrogen Easy-DNA Kit extraction method for large samples and Bio-Rad Aquapure outperform other methods for extraction of DNA from poultry fecal samples, although these methods do not necessarily recover all available DNA. They will be used in future studies to monitor the dynamics of microbial communities of the avian ceca.

Salmonella Prevalence in Market-Age Turkeys On-Farm and at Slaughter

The objective of this study was to compare the prevalence of Salmonella in market-age turkeys on-farm and at slaughter (i.e., before and after feed withdrawal, catching, loading, transportation, and preslaughter holding). Thirty birds were randomly selected from each of 6 commercial turkey flocks scheduled to be loaded and shipped to the abattoir during the evening of the same day. Selected birds were euthanized on the farm, and the cloacal contents, large intestine, crop, ceca, liver and gallbladder, and spleen were aseptically collected. At the abattoir, 30 birds from the same flock were randomly selected from the slaughter line, and the crop, ceca, liver and gallbladder, and spleen were collected for subsequent culture at the laboratory. All flocks studied were positive for Salmonella at slaughter. No statistical difference was found between the overall prevalence on-farm and at slaughter. At both sampling points, the overall prevalence found was 33.3%. Diverging prevalence estimates were obtained based on the different sample types collected on-farm and at slaughter. In both cases, cecal content samples had the highest relative sensitivity (73.3% on-farm and 68.3% at slaughter). This study demonstrates that the preslaughter practices of feed withdrawal, catching, loading, transportation, and holding do not significantly alter the prevalence of Salmonella in market-age turkeys. Therefore, our results suggest that it may be possible to monitor the Salmonella status of turkey production farms based on samples collected at the abattoir.

Effect of short-term lairage on the prevalence of Salmonella enterica in cull sows

This study was designed to compare Salmonella enterica prevalence in sows held in a holding pen at the abattoir for approximately 2 h (hold sows) with sows slaughtered immediately after transport to the abattoir (no-hold sows). Cull sows (n = 160) were sampled from four sampling periods over 8 weeks (February to March 2002) at the abattoir. Sows originated from an integrated swine farm and were sent to a live-hog market and then to the slaughter facility. Before testing, sows entered the abattoir pen and four 100-cm2 four-ply gauze squares were placed randomly on the pen floor for S. enterica culture. Sows were alternatively assigned to the hold or no-hold group. Samples collected from sows during slaughter were ileocecal lymph node, cecal contents, transverse colon contents, subiliac lymph node, sponge swabs of the left and right carcass section (300 cm2), and chopped meat. Overall, S. enterica was isolated from 44% (35 of 80) of the no-hold sows, which was significantly less (P < 0.05) than 59% (47 of 80) of the held sows. Also, no-hold sows had a lower cecal content prevalence (39%, 31 of 80) compared with that (55%, 44 of 80) of held sows (P < 0.05). S. enterica serovars isolated from no-hold sows were Brandenburg (n = 16), Derby (n = 12), Hadar (n = 8), Infantis (n = 6), Johannesburg (n = 3), 6,7:z10-monophasic (n = 3), and Typhimurium (n = 1). S. enterica serovars isolated from held sows (n = 61 isolates) were Derby (n = 19), 6,7: z10-monophasic (n = 15), Brandenburg (n = 10), Infantis (n = 6), Hadar (n = 5), Johannesburg (n = 4), and Tennessee (n = 2). Serovars recovered from the pen were Reading (n = 6), Derby (n = 4), Uganda (n = 2), and Manhattan (n = 2). Results of this study suggest that holding pens contribute to increased S. enterica carriage in cull sows. Abattoir holding pens might be an important control point for S. enterica in the ground pork production chain.

The role of dietary vitamin E in experimental Listeria monocytogenes infections in turkeys

The current study was designed to determine if dietary vitamin E influenced either the gut clearance or levels of peripheral blood CD4+ and CD8+ T lymphocytes in adult turkeys experimentally infected with Listeria monocytogenes. Turkeys were fed vitamin E (0, 100, or 200 IU) from day of hatch to time of necropsy. After 6 wk on the experimental diet, turkeys were orally inoculated with L. monocytogenes (approximately 10(9) cfu). To monitor infection status, cloacal swabs were taken on selected days post-inoculation (DPI). At necropsy, samples of viscera, including liver, spleen, cecum, duodenum, ileum, and colon were collected and cultured for L. monocytogenes. In experiments 1 and 2, recovery of L. monocytogenes from cloacal swabs, tissues, and intestines from turkeys fed vitamin E was generally lower than that from turkeys fed the control diet, although these differences were not statistically significant. When data from both trials were combined, L. monocytogenes was cultured less frequently from cloacal swabs of the vitamin E-treated group (200 IU) on 2 and 3 DPI, when compared to controls (0 IU, P < 0.01). There were no changes in virulence characteristics of L. monocytogenes cells, as measured by in vitro killing of Ped-2E9 cells, recovered from cloacal swabs or tissues of experimentally infected turkeys fed the control or a vitamin E treatment diet. Flow cytometric analysis indicated that CD4+ and CD8+ peripheral blood T lymphocytes were elevated at 6 and 8 DPI in infected turkeys given 200 IU vitamin E.

Impact of commercial preharvest transportation and holding on the prevalence of Salmonella enterica in cull sows

The objective of this study was to examine the prevalence of Salmonella enterica in cull sows at various stages from the farm to the abattoir. Cull sows (n=181) were sampled over 10 weeks. Fecal samples (10 g each) were collected on the farm ca. 24 h before loading and at the live-hog market ca. 3 h before loading. Samples (ileocecal lymph nodes, cecal contents, feces from the transverse colon, ventral thoracic lymph nodes, subiliac lymph nodes, sponge swabs of the left and right carcass sections, and chopped meat) were collected at the abattoir. The percentages of positive fecal samples on the farm and at the live-hog market were 3% (5 of 181 samples) and 2% (3 of 181 samples), respectively. After transport from the live-hog market (10 h) and holding at the abattoir (6 h), 41% (74 of 180) of cull sows yielded S. enterica in one or more sampled tissues. The isolation rate for total cecal contents (33%; 60 of 180 samples) was significantly (P<0.05) higher than those for ileocecal lymph nodes (7%; 12 of 181 samples), feces (11%; 20 of 181 samples), and ventral thoracic and subiliac lymph nodes (2%; 4 of 181 samples). Before a 2% lactic acid carcass wash (lasting 8 to 9 s), 14% (25 of 180) of carcasses were positive, compared with 7% (12 of 179) after the wash (P<0.05). Two S. enterica serotypes, Derby and Infantis, were found on the farm and at the live-hog market. At the abattoir, 12 serotypes that had not previously been found on the farm or at the live-hog market were recovered. The results of this study demonstrate that transport and holding practices may contribute to an increase in S. enterica infection prior to slaughter to levels much higher than those found on the farm.

Quality characteristics of irradiated ready-to-eat breast rolls from turkeys fed conjugated linoleic acid

The objective of this study was to determine the effect of irradiation on the quality of ready-to-eat (RTE) breast rolls from turkeys fed conjugated linoleic acid (CLA). The oxidative stability of RTE turkey rolls was improved by the dietary CLA treatment. Irradiation increased the production of acetaldehyde, 3-methyl-butanal, 2-methyl-butanal, and total volatiles in turkey rolls but had little effect on other aldehydes. Irradiation also produced new volatiles, including sulfur compounds, not detected in nonirradiated turkey breast rolls. We detected significantly higher amounts of alkanes with nine or higher carbons in irradiated samples than in nonirradiated samples. Irradiation increased the redness of RTE turkey breast rolls, but the degree of redness and the amount of total volatiles decreased with storage. CLA treatment lowered the redness (a*) and increased the lightness (L*) of RTE turkey breast rolls during the entire storage period. Sensory evaluation revealed that irradiation produced off-flavor, but CLA and irradiation did not influence the texture and juiciness of RTE turkey breast rolls. Consumers did not like the off-flavor but preferred the color induced by irradiation to nonirradiated RTE turkey breast rolls.

Salmonella enterica infections in market swine with and without transport and holding

The objective of this study was to compare, by using identical sample types, the Salmonella enterica prevalences and serovar diversities between pigs necropsied on the farm and those necropsied at the abattoir after transport and holding. We necropsied 567 market weight pigs (>70 kg) from six herds. Pigs were alternately assigned to be necropsied on the farm or at the abattoir. One-half of the group was sent in clean, disinfected trailers to slaughter at a commercial abattoir. After transport (mean distance, 169 km) and 2 to 3 h of holding in antemortem pens, these pigs were necropsied. The 50 pigs remaining on the farm were necropsied the following day. The same sample types and amounts were collected for S. enterica culture at both locations. Results show a sevenfold-higher (P < 0.001) S. enterica isolation rate from pigs necropsied at the abattoir (39.9%; 114 of 286) than from those necropsied on the farm (5.3%; 15 of 281). This difference was also observed for each individual herd. All sample types showed a significantly higher prevalence when comparing abattoir to on-farm collection, respectively: lymph nodes, 9.15 versus 3.6%; cecal contents, 13.6 versus 1.8%; 1 g of fecal matter, 25.2 versus 0.7%. Recovery of additional serovars at the abattoir suggests the pigs are receiving S. enterica from extra-farm sources. This study demonstrates that rapid infection during transport, and particularly during holding, is a major reason for increased S. enterica prevalence in swine. This finding identifies the holding pen as an important S. enterica control point in the pork production chain.

Comparison of culture, multiplex, and 5' nuclease polymerase chain reaction assays for the rapid detection of Yersinia enterocolitica in swine and pork products

Bacteriological culture was compared with multiplex and fluorogenic (TaqMan) polymerase chain reaction (PCR) assays for the detection of attachment invasion locus (ail)-bearing Yersinia enterocolitica in market weight swine, chitterlings, and ground pork. The TaqMan assay detected 1 pg of purified Y. enterocolitica DNA, whereas conventional gel-based PCR detected I ng of the same. The presence of ail-bearing Y. enterocolitica was tested in pork and feces artificially inoculated with Y. enterocolitica strain NADC 5561. The sensitivity limits of culture, multiplex, and TaqMan PCR assays were 4 x 10(3), 4 x 10(2), and 0.4 CFU/g, respectively, for the artificially inoculated pork. The sensitivity limits were 4 x 10(2), 4 x 10(2), and 0.4 CFU/g, respectively, for feces after a 48-h enrichment in a Yersinia selective broth. By the culture method, Y. enterocolitica was not detected in any of the swine specimens (n = 2,403) examined. By contrast, it was detected in 48 (2%) of the swine samples screened using the multiplex PCR and in 656 (27.2%) of these samples using the TaqMan assay. Using the culture method, Y. enterocolitica was detected in 8% of chitterling samples (n = 350) and in none of the ground pork samples (n = 350). It was identified in 27% of the chitterling samples using multiplex PCR and in 79% of these samples using the TaqMan assay. Ten percent of the ground pork samples contained Y. enterocolitica, as determined by the multiplex PCR, and 38% based on the TaqMan assay. The results suggest that pork products harbor more ail-bearing Y. enterocolitica than selected organs of freshly slaughtered hogs and that the TaqMan assay is more sensitive than either the multiplex PCR or traditional culture methods.

The effect of lairage on Salmonella isolation from market swine

The objective of this paper was to evaluate the effect of lairage (holding >12 h during transport to slaughter) in clean facilities on Salmonella isolation from market swine. We tested 30 market-bound pigs (about 240 lb [110 kg]) on each of 10 occasions from an Iowa farrow-to-finish operation with about 600 sows. All pigs were slaughtered, and samples were collected at a large Midwest abattoir. On the farm, fecal samples were collected for culture of Salmonella. Pigs were alternately assigned to a lairage treatment (holding in a clean, disinfected facility at the National Animal Disease Center) group or a control group (remaining on the farm). After about 18 h, both groups were transported (about 137 km) to a large Midwest abattoir, commingled, and slaughtered. After slaughter, samples were collected for culture of Salmonella (feces from the distal colon, ileocecal lymph nodes, cecal contents, ventral thoracic lymph nodes, subiliac lymph nodes, and carcass swabs). Diaphragm sections were collected for serum ELISA. Salmonella enterica Derby was the only serotype isolated from farm fecal samples (3.4%, 10 of 290). Multiple serotypes (n = 17) were isolated from 71.8% (196 of 273) of the pigs when abattoir-collected samples were cultured: cecal contents (21.2%. 58 of 273), distal colon contents (52%, 142 of 273), and ileocecal lymph nodes (43.6%, 119 of 273). There were lower Salmonella isolation rates from the lairaged pigs (P < 0.05). The predominant serotype isolated at the abattoir varied by week of the study. This study suggests that pigs became internally contaminated with Salmonella after leaving the farm, possibly while in the abattoir holding pens, and that 18 h lairage, in clean facilities, does not increase shedding.

Development of a fluorogenic 5' nuclease PCR assay for detection of the ail gene of pathogenic Yersinia enterocolitica

In this report we describe the development and evaluation of a fluorogenic PCR assay for the detection of pathogenic Yersinia enterocolitica. The assay targets the chromosomally encoded attachment and invasion gene, ail. Three primer-probe sets (TM1, TM2, and TM3) amplifying different, yet overlapping, regions of ail were examined for their specificity and sensitivity. All three primer-probe sets were able to detect between 0.25 and 0.5 pg of purified Y. enterocolitica DNA. TM1 identified all 26 Y. enterocolitica strains examined. TM3 was able to detect all strains except one, whereas TM2 was unable to detect 10 of the Y. enterocolitica strains tested. None of the primer-probe sets cross-reacted with any of the 21 non-Y. enterocolitica strains examined. When the TM1 set was utilized, the fluorogenic PCR assay was able to detect </=4 Y. enterocolitica CFU/ml in pure culture and 10 Y. enterocolitica CFU/ml independent of the presence of 10(8) CFU of contaminating bacteria per ml. This set was also capable of detecting </=1 CFU of Y. enterocolitica per g of ground pork or feces after a 24-h enrichment in a Yersinia selective broth.

Fecal shedding of Campylobacter and Arcobacter spp. in dairy cattle

Campylobacter jejuni, Campylobacter coli, and Arcobacter spp. were detected in feces of healthy dairy cows by highly specific multiplex-PCR assays. For C. jejuni, at this one-time sampling, cows from 80.6% of farm operations (n = 31) and 37.7% of individual dairy cattle fecal samples (n = 2,085) were positive. Farm management factors were correlated with prevalence in herds in which >25% of cows were positive for C. jejuni. Statistical significance was set at a P of 0.20. Using these criteria, application of manure with broadcast spreaders (P = 0.17), feeding of whole cottonseed or hulls (P = 0.17) or alfalfa (P = 0.15), and accessibility of feed to birds (P = 0.17) were identified as possible risk factors for C. jejuni infection. C. coli was detected in at least one animal in 19.4% of operations and 1.8% of individual cows (n = 2,085). At the herd level, use of broadcaster spreaders was not a risk factor for C. coli infection. For Arcobacter, cows from 71% of dairy operations (n = 31) and 14.3% of individual dairy cattle fecal samples (n = 1,682) were positive. At the herd level, for Arcobacter spp., feeding of alfalfa (P = 0.11) and use of individual waterers (P = 0.19) were protective. This is the first description of Arcobacter spp. in clinically healthy dairy cattle and the first attempt to correlate their presence with C. jejuni.

Natural and experimental infections of Arcobacter in poultry

Arcobacter butzleri causes human enteritis and is frequently recovered from poultry carcasses. The purpose of this study was to determine 1) the natural distribution of A. butzleri in poultry and 2) its relative pathogenicity in experimentally infected poultry. Cloacal samples (n = 407) were collected on four occasions from three flocks of chickens. Overall, Arcobacter spp. were recovered from 15% of the birds; A. butzleri was identified in 1% of cloacal samples. Three experimental trials were conducted to determine the susceptibility of birds. In Trial 1, 3-d-old chicks (n = 62) were divided into three groups and infected per os with 1) A. butzleri American Type Culture Collection (ATCC) 49616, 2) a suspension of four field strains of A. butzleri isolated from retail purchased chicken, and 3) Campylobacter jejuni (positive control). Arcobacter was not detected in cloacal swabs or in cecal samples of chicks through Day 5 postinfection; C. jejuni was detected in cloacal swabs of all positive control birds. In Trial 2, 5-d-old outbred turkey poults (n = 88) were infected as described above with the addition of a group infected with a suspension of four field strains of A. butzleri from turkey meat. Arcobacter butzleri was recovered from either cloacal swabs or cecal contents of only 6.0% of birds (4 of 67); C. jejuni was recovered from 100% of the positive control birds (n = 21). In Trial 3, 3-d-old turkey poults of the highly inbred Beltsville White strain (n = 141) were experimentally inoculated. In contrast to earlier trials, A. butzleri was recovered overall from the cloacal swabs or tissues of 65% of the turkeys.

Isolation of Arcobacter butzleri from ground water

Arcobacter butzleri was isolated from a contaminated ground water source. These organisms, previously designated as aerotolerant Campylobacter, were capable of surviving in the ground water environment. Specific DNA probes were used to characterize the isolates in the initial identification and survival studies. Arcobacter butzleri was found to be sensitive to chlorine inactivation.

Prevalence and genetic variability of Arcobacter species in mechanically separated turkey

A survey for Arcobacter spp. and Arcobacter butzleri in mechanically separated turkey was conducted during the winter of 1995 and summer and fall of 1996. Arcobacter spp. and A. butzleri were identified by polymerase chain reaction and species-specific oligonucleotide probes. Arcobacter spp. were isolated from 77% (303 out of 395) of the mechanically separated turkey samples with 74% (223 out of 303) of these samples positive for A. butzleri. Of the 121 A. butzleri isolates tested, 86 different patterns were evident following amplification of enterobacterial repetitive intergenic consensus sequences. The extent of genetic polymorphism indicated multiple sources of contamination.

Multiplex PCR for the identification of Arcobacter and differentiation of Arcobacter butzleri from other arcobacters

A multiplex polymerase chain reaction (PCR) assay to identify Arcobacter isolates and to distinguish A. butzleri from other arcobacters is described. The test uses two primer sets. Set I targets a section of the 16S rRNA genes of Arcobacter spp. Set II amplifies a portion of the 23S rRNA genes unique to A. butzleri. Specificity of the primer sets was evaluated using ATCC reference strains of A. butzleri, A. cryaerophilus, A. skirrowii, Bacteroides spp., Campylobacter spp., Helicobacter spp. and Wolinella succinogenes. Upon PCR amplification, all of the Arcobacter isolates yielded a 1223 bp product, whereas A. butzleri ATCC 49616 exhibited both a 1223 bp and a 686 bp product. No PCR product was observed for other closely related ATCC strains (n = 37). We next analyzed by multiplex PCR field strains of Arcobacter spp. (n = 108) which had been previously characterized to the species level by either DNA-DNA hybridization, dot blot hybridization, ribotyping or by serology. The 1223 bp multiplex PCR product identified all of the isolates as Arcobacter. The presence of both the 1223 and 686 bp amplicons identified 66 strains as A. butzleri. Speciation by multiplex PCR agreed with results obtained by the other methods. The multiplex PCR assay is specific, rapid and easy to interpret and, thus, will aid in elucidating the prevalence, epidemiology and zoonotic potential of Arcobacter.

Specific identification of Campylobacter fetus by PCR targeting variable regions of the 16S rDNA

Campylobacter fetus is recognized as a human and animal pathogen. The isolation and differentiation of C. fetus in diagnostic laboratories is hindered by its relatively slow growth and lack of distinguishing biochemical characteristics. We developed a fast, reliable PCR assay that specifically amplifies a 554-bp segment of the 16S rDNA from C. fetus. Fifty-two ATCC reference strains and 255 bacterial field isolates comprising the genera Campylobacter, Arcobacter, Helicobacter, Escherichia, Listeria, Salmonella, and Wolinella were evaluated using this PCR protocol. Only C. fetus strains were amplified. Sequence analysis of amplicons from ATCC and field strains of C. fetus confirmed the presence of the target DNA fragment. The detection limit of the technique was 5.9 x 10(3) CFU/ml. This PCR assay can yield reliable detection of C. fetus within 3 h after isolation of presumptive colonies on agar plates.

Detection of Arcobacter species in gastric samples from swine

Swine stomachs were surveyed for evidence of Arcobacter spp. and Helicobacter spp. infections associated with gastric ulceration. A nested PCR test targeted to the 16S rRNA was developed to detect many Arcobacter spp. and Helicobacter spp. An internal oligonucleotide probe was used for differentiation and confirmation of the PCR product. Tissue samples were obtained from the nonglandular and glandular regions of 86 swine stomachs. Evidence of infection with these microbes was detected in 51%, with 77% of the positive samples being identified as A. butzleri using a highly specific probe. Nonglandular stomach samples (44%) were more likely to be positive by PCR than samples from the glandular (23%) region. Gross lesions of any stage of gastric ulceration, ranging from parakeratosis, erosions and ulceration, were observed in 24% of stomachs examined. Of 21 samples with lesions, 52% were positive by the broadly reactive PCR assay for Arcobacter spp. and Helicobacter spp. The majority of PCR-positive samples (75%) had no gross lesions. When a single step PCR assay that was more specific for Arcobacter spp. was used on the nonglandular stomach samples, 10.4% of the 86 samples were positive. Arcobacter spp. were cultured from four of the sample stomachs. Partial sequencing of the 16S rRNA gene identified the isolates as A. butzleri (n = 2), A. cryaerophilus, (n = 1), and a mixed culture of A. butzleri and another Arcobacter spp. (n = 1). A single step PCR assay targeted to the urease gene and culturing methods were used to screen for H. pylori or other closely related urease positive bacteria, but none were found.

Classification of Arcobacter species isolated from aborted pig fetuses and sows with reproductive problems in Brazil

Seventeen field isolates of Arcobacter species were recovered in Brazil from aborted porcine fetal livers (n = 3), kidneys (n = 2), and thoracic fluid (n = 1). Arcobacter species were also recovered from uterine and oviductal tissues (n = 5) and a placenta from sows with reproductive problems. These isolates were initially presumed to be Arcobacter cryaerophilus on the basis of aerobic growth at 30 degree C, indoxyl acetate hydrolysis, catalase and oxidase reactions, growth on MacConkey agar, sensitivity to 3.5% sodium chloride, and susceptibility to nalidixic acid (40 mg/ml). The isolates were confirmed as Arcobacter using polymerase chain reaction, and were classified as A. cryaerophilus 1A (24%), A. cryaerophilus 1B (71%), and A. butzleri (6%) using restriction fragment length polymorphism.

Application of multiplex polymerase chain reaction for rapid identification of Campylobacter jejuni and C coli associated with reproductive failure

OBJECTIVE

To evaluate a multiplex polymerase chain reaction (PCR) to distinguish Campylobacter jejuni from C coli as causes of reproductive failure.

PROCEDURE

Review of clinical cases of reproductive failure attributed to C jejuni or C coli.

RESULTS

A case of swine abortion was attributable to infection with C coli. The porcine abortion isolates were verified as C coli by restriction fragment length polymorphism and multiplex PCR. Cases of endometritis in a fox and in mink caused by C jejuni were reviewed, and isolates were confirmed as C jejuni by results of the multiplex PCR.

CONCLUSION

Multiplex PCR was useful in identifying C coli and C jejuni recovered from atypical cases of reproductive failure. Multiplex PCR in conjunction with conventional assays may be useful for verifying other unusual instances of campylobacteriosis.

Differentiation of Campylobacter jejuni and Campylobacter coli by polymerase chain reaction

A multiplex PCR assay was developed using two primer sets for the identification and differentiation of Campylobacter coli and Campylobacter jejuni. Primer Set I amplifies a 460-bp fragment present in C. coli and C. jejuni. Set II amplifies a 160-bp target unique to C. jejuni. When the assay was performed on reference strains, amplification of C. coli yielded only the 460-bp fragment. Amplification of C. jejuni generated both the 160- and 460-bp fragments. Campylobacter field strains (n = 85) isolated from raw poultry were identified by PCR and by conventional biochemical methods. Species determination by the two methods agreed for 83 of the 85 isolates examined. By PCR, 23 were identified as C. coli and 62 as C. jejuni. One isolate was unidentifiable by biochemical testing. The PCR assay identified this isolated as C. coli. In addition, one strain which was identified as C. coli by biochemical testing was determined to be C. jejuni by PCR. The PCR assay offers an alternative to traditional biochemical typing methods for the identification and differentiation of C. coli and C. jejuni isolated from poultry. It is accurate, simple to perform, and can be completed within 8 h.

Identification of Arcobacter isolates by PCR

A polymerase chain reaction (PCR) assay was developed for the identification of the three species of Arcobacter which have been recovered from clinically ill or healthy humans and/or livestock, namely Arcobacter butzleri, Arcobacter skirrowii and Arcobacter cryaerophilus. The assay utilizes primers targeted to the genes encoding 16S rRNA of Arcobacter spp. The assay reduces the amount of time required to positively identify strains of Arcobacter.

The use of listeriolysin O in an ELISA, a skin test and a lymphocyte blastogenesis assay on sheep experimentally infected with Listeria monocytogenes, Listeria ivanovii or Listeria innocua

Purified listeriolysin O (LLO) was evaluated as a specific antigen to detect both humoral and cell mediated immune responses of sheep infected with Listeria monocytogenes. Six sheep (two in each group) were orally inoculated with 10(10) organisms of L. monocytogenes, L. ivanovii, or L. innocua. Only the L. monocytogenes inoculated sheep had an elevated temperature (> 42 degrees C) and after 15 days had anti-LLO antibodies as assessed by an ELISA. In a blastogenesis assay, only peripheral blood mononuclear cells (PBMC) from L. monocytogenes-infected sheep responded to LLO, while PBMC from all the sheep responded somewhat to heat-killed L. monocytogenes bacteria. In a skin test, only L. monocytogenes-infected sheep exhibited a positive reaction to injected LLO, while all the Listeria-infected sheep reacted to heat-killed bacteria. On day 120 postinfection, all of the sheep were orally inoculated with L. monocytogenes. Only the four that had not been previously given L. monocytogenes exhibited an elevated temperature (> 42 degrees C). 80 days later, sera from all of the animals were positive for anti-LLO antibodies. Thus, prior exposure to L. ivanovii or L. innocua does not protect against a L. monocytogenes challenge. These results suggest LLO is an excellent antigen for use in detecting Listeria infection in sheep. However, whether LLO will be useful in differentiating chronically infected animals from animals that have recovered, has yet to be investigated.

Infection of cesarean-derived colostrum-deprived 1-day-old piglets with Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii

Neonatal piglets have been used as models to study human campylobacteriosis and helicobacteriosis. The purpose of this study was to determine the relative pathogenicities, on the basis of the duration of fecal shedding and colonization of tissues, of three Arcobacter species in 1-day-old cesarean-derived colostrum-deprived piglets. Two experiments were conducted. In experiment 1, two piglets each were infected per os with either Arcobacter butzleri ATCC 49616, Arcobacter cryaerophilus 1B ATCC 43159, Arcobacter skirrowii CCUG 10374, or the three field strains of A. butzleri (approximately 5 X 10(9) CFU per piglet). Rectal swab samples were taken prior to infection and daily thereafter for up to 7 days. Arcobacter spp. were detected at least once in rectal swab samples of all but one of the experimentally infected piglets but not in the control. At necropsy, A. butzleri was recovered from the lung, kidney, ileum, or brain tissues of the four infected piglets which had received either the field strain or the ATCC type strain of A. butzleri. A. cryaerophilus 1B was detected in rectal swab samples for up to 7 days postinfection but was not cultured from tissues at necropsy. Arcobacters were detected in the rectal swab sample of the A. skirrowii-infected piglet only on day 3 postinfection; no isolates were obtained from tissues at necropsy. No gross pathological lesions were consistently noted in the experimentally infected piglets. In experiment 2, two piglets each were infected per os with A. butzleri ATCC 49616, A. cryaerophilus 1A ATCC 43158, A. skirrowii CCUG 10374, or the single A. butzleri field strain Yard J/c (approximately 5 X 10(9) CFU per piglet). Arcobacter spp. were cultured from rectal swab samples of all but one of the experimentally infected piglets at least once. At necropsy Arcobacter spp. were cultured from the liver, kidney, ileum, or brain tissues of two of the four A. butzleri-infected piglets. However, no severe gross pathology was noted. These data suggest that Arcobacter spp., especially A. butzleri, can colonize neonatal pigs.

Epidemiologic evaluation of encephalitic listeriosis in goats

OBJECTIVE

To evaluate host and environmental factors associated with the development of encephalitic listeriosis in goats.

DESIGN

Retrospective analysis of diagnostic laboratory records and survey of veterinarians and goat producers.

SAMPLE POPULATION

355 goat herds accessible through laboratory records; 38 veterinarians who treated goats and 76 goat producers.

PROCEDURE

Data regarding breed and use for goats affected with encephalitic listeriosis were obtained from surveys and case follow-up information. Listeria monocytogenes isolates from the brains of 7 affected goats were serotyped and subjected to DNA restriction analysis.

RESULTS

Odds ratio for the development of encephalitis listeriosis in Angora (mohair-producing) goats was 22.9 by use of diagnostic laboratory records. Survey also revealed a high prevalence in herds of Angora and other breeds that subsisted on woody browse, although Angora goats feeding predominantly on hay or pasture were not affected. Listeria monocytogenes isolates from 4 Angora goats in 3 herds differed in DNA restriction patterns, although the pattern was identical in 3 other goats from another herd.

CLINICAL IMPLICATIONS

Encephalitic listeriosis can be observed in all goat breeds, but a lifestyle of heavy browse consumption seems important to the development of disease in some herds.

Detection of Arcobacter spp. in Ground Pork by Modified Plating Methods

A modified cefsulodin-irgasan-novobiocin (CIN) medium was developed for the recovery of Arcobacter spp. from meats. Modified CIN was compared to brain heart infusion agar supplemented with 10% bovine blood and cephalothin, vancomycin, and amphotericin B (CVA) as well as brain heart infusion agar supplemented with 10% bovine blood and no antibiotics. The three media were used to recover Arcobacter spp. in a survey of pork-processing plants. Examination of ground pork (149 samples) from one Iowa slaughter facility (Plant #1) revealed that 89 percent of the samples were positive for Arcobacter spp. In a second survey conducted 9 months later involving that same plant and four others, only 5% of the samples from the four plants were found to be positive for Arcobacter spp. Again, 90% of the samples were positive from Plant #1. It was not determined whether the sanitary practices during slaughter or the rearing of pigs on the source farms contributed to the prevalence of Arcobacter spp. in one plant versus another.

Phenotypic and ribosomal RNA characterization of Arcobacter species isolated from porcine aborted fetuses

Aerotolerant organisms resembling Campylobacter, now designated as Arcobacter, have been described from aborted farm animals and from cases of human enteritis worldwide. The goals of this study were 1) to attempt to recover Arcobacter spp. from cases of porcine abortion, 2) to characterize these isolates by phenotype and ribotype, and 3) to compare the usefulness of ribotype and phenotype patterns for identifying Arcobacter butzleri and the DNA hybridization groups 1A and 1B of A. cryaerophilus. Isolates of Arcobacter spp. from North Carolina and Iowa were recovered from porcine tissues. In Iowa, Arcobacter spp. were recovered from 43% (13/30) of porcine abortion cases evaluated. Isolations were made from placenta (44%), kidney (44%), and stomach contents (12%), which were the only tissues examined. The most reliable biochemical tests for A. butzleri included growth in 1% glycine and in 1.5% NaCl, weak catalase activity, and resistance to cadmium chloride. Arcobacter cryaerophilus strains were characterized by strong catalase activity and sensitivity to cadmium chloride. The DNA hybridization groups 1A and 1B of A. cryaerophilus could not be distinguished by biochemical tests. This represents the first description of A. cryaerophilus DNA group 1A in animals within the United States.

Biphasic culture of Arcobacter spp

Arcobacter spp. have recently been genetically differentiated as a genus distinct from Campylobacter. Physiologically, Arcobacter spp. are aerotolerant bacteria, while Campylobacter spp. are microaerophilic. However, since Arcobacter spp. have been difficult to grow to high population densities in broth media, alternative culture techniques were investigated. A biphasic culture system was developed in 25 cm2 tissue culture flasks. Biphasic culture, consisting of a solid phase of 10% bovine blood agar and a liquid phase of Brain Heart Infusion broth, was found to increase bacterial population densities by more than 2 log10 cycles for strains of A. butzleri and A. skirrowii. A strain of A. cryaerophilus, which was non-culturable in broth culture, attained population densities of 10(9) cells ml-1 in biphasic culture. Neither the addition of fetal bovine serum to the liquid nor an increase in the surface area from 25 to 75 cm2 resulted in increased cell densities.

Arcobacter-specific and Arcobacter butzleri-specific 16S rRNA-based DNA probes

The genus Arcobacter encompasses gram-negative, aerotolerant, spiral-shaped bacteria formerly designated Campylobacter cryaerophila. Two genus-specific 16S rRNA-based oligonucleotide DNA probes (23-mer and 27-mer) were developed. The probes hybridized with strains of Arcobacter butzleri (n = 58), Arcobacter cryaerophilus (n = 19), and Arcobacter skirrowii (n = 17). The probes did not cross-react with any of the reference strains of Campylobacter, Helicobacter, including "Flexispira rappini," or Wolinella. The 27-mer hybridized with 61 Arcobacter spp. field isolates originating from late-term aborted porcine (n = 54) and equine (n = 2) fetuses and humans with enteritis (n = 5). The species of Arcobacter isolates (n = 56) recovered from aborted livestock fetuses were determined by ribotyping and were as follows: A. cryaerophilus group 1A (11 of 56; 20%), A. cryaerophilus group 1B (37 of 56; 66%), A. butzleri (5 of 56; 9%), and unknown (3 of 56; 5%). The five human field strains were identified as A. butzleri. A species-specific DNA probe (24-mer) for A. butzleri was also developed since there is evidence that this organism may be a human pathogen. This probe hybridized with previously characterized strains of A. butzleri (n = 58), with 10 field strains identified as A. butzleri by ribotyping and with 2 strains having an indeterminate ribotype. The A. butzleri-specific probe did not cross-react with strains of A. skirrowii (n = 17) and A. cryaerophilus (n = 19).

Detection of anti-listeriolysin O in dairy cattle experimentally infected with Listeria monocytogenes

A dot-blot assay and an enzyme-linked immunosorbent assay (ELISA) to detect listeriosis in dairy cattle were developed that detected anti-listeriolysin O antibodies in the serum of cows experimentally infected with Listeria monocytogenes. The tests utilized purified listeriolysin O (LLO) as the detection antigen and streptolysin O (SLO) to absorb cross-reacting antibodies. The two tests were compared with an agglutination test that used formalin-killed whole L. monocytogenes cells. Blood samples were collected periodically from 17 cows after intramammary gland infection, and the development of anti-LLO antibodies was followed by an agglutination test, the dot-blot test, and the ELISA. In general, an agglutination titer of > 640 was needed for a positive dot-blot anti-LLO test for nonpregnant cows. However, 1 pregnant cow with an agglutination titer of 20 was positive in the dot-blot test. The ELISA was as sensitive as the dot-blot assay but gave a quantitative measurement to distinguish serum samples of positive reactors from cross-reactors. The specificity of the LLO-based tests was further evaluated using serum from cows that had been experimentally infected with Staphylococcus aureus, 17 of which had agglutination titers for L. monocytogenes > 640. These elevated agglutination titers were probably due to cross-reacting bacterial antigens because serum from 9 of 17 of these animals did not react to the purified LLO antigen. A positive response to the LLO-based dot-blot and ELISA assays is indicative of previous or current infection with L. monocytogenes.

Use of DNA analysis of Pasteurella haemolytica biotype T isolates to monitor transmission in bighorn sheep (Ovis canadensis canadensis)

Pneumonia has been identified as a major cause of poor lamb survival in indigenous herds of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) in central Idaho. Pasteurella haemolytica was isolated from five adult Rocky Mountain bighorn ewes captured from a free-ranging herd in central Idaho. The lambs from two of these ewes delivered by cesarean section were free of P. haemolytica until 40 days of age and after repeated contact with their dams. The lambs subsequently developed signs of pneumonia, and P. haemolytica was isolated from nasal, pharyngeal, and transtracheal wash samples from each lamb. All P. haemolytica biotype T isolates from the ewes and lambs, as well as those from a 9-month-old lamb of the same herd from which samples for culture were obtained 2 years earlier, were subjected to HaeIII restriction enzyme analysis (REA) and ribotyping. Two ribotypes and seven REA patterns were visually distinguishable by these procedures. Similarity coefficients (SAB) of 0.09 to 0.95 were calculated for the seven REA patterns. The REA patterns of the isolates from the lambs were identical (SAB = 1.0). The isolates from the lambs also had SAB values of 1.0, which was indicative of identity with one of the seven isolates cultured from the ewes at the time of capture and with the organism isolated from the 9-month-old lamb. These procedures have the discriminatory capabilities necessary to monitor the transmission of specific strains of bacteria within and between animal populations.

Oligodeoxynucleotide probes for Campylobacter fetus and Campylobacter hyointestinalis based on 16S rRNA sequences

Deoxyoligonucleotide probes were constructed for the identification of Campylobacter fetus and Campylobacter hyointestinalis based on 16S rRNA sequence data. Probes were targeted to hypervariable regions of 16S rRNA. Specificity of oligonucleotide probes was tested in a colony blot assay with type strains of 15 Campylobacter and Arcobacter species as well as in a slot blot format using genomic DNA extracted from field strains of C. fetus and C. hyointestinalis. Two oligonucleotides were constructed for C. fetus that hybridized with equal specificity with each of 57 biochemically confirmed isolates of C. fetus but not with any other Campylobacter species. The C. hyointestinalis probe reacted with 47 of 48 biochemically confirmed field isolates of C. hyointestinalis. In Southern blot hybridization of BglII digests of genomic DNA, the respective probes reacted within three restriction fragments of either C. hyointestinalis (7.2, 8.2, and 10.1 kb) or C. fetus (7.0, 7.7, and 9.0 kb). This suggests multiple copies of genes encoding 16S rRNA.

Restriction enzyme analysis of Listeria monocytogenes strains associated with food-borne epidemics

Listeria monocytogenes (serotype 4b) has caused four major food-borne epidemics in North America. In this study, L. monocytogenes isolates from the Nova Scotia (Canada), Boston (Mass.), and Los Angeles (Calif.) outbreaks were examined by restriction enzyme analysis with the endonuclease HhaI. Human isolates (n = 32) from the 1981 Canadian outbreak were compared with a strain recovered from coleslaw, which was epidemiologically incriminated as the vehicle of infection. After HhaI digestion, 29 of 32 isolates exhibited the restriction enzyme pattern of the reference coleslaw isolate. The restriction enzyme patterns of the nine clinical isolates from the 1983 Massachusetts outbreak were identical to each other but differed from those of raw milk isolates recovered from sources supplying the pasteurizer. Isolates (n = 48) from the 1985 California outbreak were evaluated. The restriction enzyme patterns of the L. monocytogenes isolates from humans and from the suspect cheese samples were identical to those of four of five cheese factory environmental isolates. Isolates from each of these outbreaks exhibited a restriction enzyme pattern that was characteristic of that outbreak. The case with which restriction enzyme analysis can be applied to all serotypes of L. monocytogenes argues for its use in the epidemiology of L. monocytogenes.

Differentiation between transmissible gastroenteritis virus and porcine respiratory coronavirus using a cDNA probe

A plasmid, pG3BS, containing a cDNA clone from the 5' coding region of the peplomer glycoprotein gene appears to be specific for enteric transmissible gastroenteritis virus (TGEV) strains and for live-attenuated TGEV vaccines. This cDNA probe is used to differentiate porcine respiratory coronavirus (PRCV) isolates from TGEV field and vaccine strains by a slot blot hybridization assay. Probe pG3BS also hybridizes to canine coronavirus (CCV) RNA but does not hybridize to antigenically related feline infectious peritonitis virus (FIPV) RNA. The RNAs of 13 enteric TGEV isolates from the United States, Japan, and England, 4 US-licensed live-attenuated TGEV vaccines, and antigenically closely related CCV were detected by pG3BS. The RNAs of FIPV and 3 US isolates of PRCV did not react with pG3BS but were detected by a TGEV-derived plasmid, pRP3. Pigs infected with either PRCV or TGEV test serologically positive for TGEV antibody by the serum neutralization test. Characterization of the virus circulating in a swine herd by the pG3BS probe will differentiate between an enteric TGEV and a respiratory PRCV infection.

Effects of dexamethasone on shedding of Listeria monocytogenes in dairy cattle

Ten lactating Holstein cows that had been given multiple injections of Listeria monocytogenes (serotype 4B, Scott A strain) via the intramammary route were allotted to 2 groups: group 1 (n = 5) was treated with the synthetic glucocorticoid, dexamethasone (0.04 mg/kg of body weight), for 3 consecutive days, and group 2 (n = 5) served as controls. Two days after the initial dexamethasone injection, the number of L monocytogenes in the milk had increased nearly 15-fold (1.16 log10) over pretreatment values. On day 3, Listeria numbers in the milk had increased by 1.83 log10, compared with pretreatment values. By day 4, Listeria numbers in the milk were approximately 100-fold (2.03 log10) greater than pretreatment numbers. Numbers remained high through day 7 and, by day 11, approached pretreatment numbers. Dexamethasone administration was accompanied by high total WBC and milk somatic cell counts and decreased eosinophil and lymphocyte numbers, and decreased milk production. The increase in shedding of L monocytogenes in the milk may reflect impairment of cell-mediated immune mechanisms and phagocytic cell functions that are critical for sustaining listerial immunity.

Antigenic and restriction enzyme analysis of isolates of Campylobacter fetus subsp venerealis recovered from persistently infected cattle

Thirty-two isolates of Campylobacter fetus subsp venerealis were obtained from 1 bull and 4 heifers with experimentally induced infection. When whole-cell antigens of isolates were cross titrated with antisera to the infecting strain, isolates from 3 heifers had limited antigenic variation, whereas whole-cell antigens of isolates from 2 cattle (the bull and a heifer) differed serologically from those of the infecting strain. Changes were detected specifically in 6 heat-labile antigens. Of the 6 heat-labile factors evaluated, all were initially present on the infecting parent strain, but not on early isolates obtained from 4 of the 5 cattle. Restriction enzyme analysis revealed minor variation in the DNA fingerprints of isolates obtained from individual cattle, thus implying stability of the Campylobacter genome once persistent infection is established. Isolates with identical restriction enzyme patterns expressed different heat-labile antigens. Correlation could not be found between the DNA electrophoretic pattern and the expression of heat-labile antigens.

Vaccination of pregnant guinea pigs with Campylobacter fetus: effects of antigen dose, Campylobacter strain, and adjuvant type

For the purpose of developing and improving vaccines to protect cattle against bovine genital campylobacteriosis, the interaction of vaccine dose, strain(s) of Campylobacter fetus, and type of adjuvant was studied in the pregnant guinea pig model. Five strains of C fetus were used in the preparation of 20 monovalent vaccines containing various doses of bacteria (0.1 mg to 20 mg, dry weight) in Freund incomplete adjuvant, Freund complete adjuvant, or aluminum hydroxide gel adjuvant. Vaccinal protection against homologous or heterologous challenge exposure with viable C fetus strains was measured in terms of infection, abortion, and serum antibody titers. Major emphasis in the study was placed on vaccines containing highly virulent C fetus subsp venerealis strains (1289 and 17761) that possess most of the heat-labile K antigens that have been identified. Vaccines incorporating strain 1289 provided greater protection against abortion than did strain 17761 vaccines (difference, 29%; P less than 0.05). A positive (P = 0.61) correlation was seen between protection from abortion and strain 1289 serum antibody titer. When the titer was greater than or equal to 4, protection was greater than 80%, whereas abortion was associated with a serum antibody titer less than or equal to 2. In an experiment comparing 2-mg vs 20-mg doses of strain 17761 prepared in aluminum hydroxide gel adjuvant, protection against challenge exposure with the heterologous strain 23 was significantly (P less than 0.05) lower than that against challenge exposure with the homologous strain at the 2-mg dose.(ABSTRACT TRUNCATED AT 250 WORDS)