Campylobacter spp. in Irish Feedlot Cattle: A Longitudinal Study Involving Pre‐harvest and Harvest Phases of the Food Chain

The aim of this study was to investigate faecal shedding and transmission of Campylobacter spp. in cohorts of cattle within a feedlot, to assess subsequent contamination of carcasses with this pathogen and to identify risk factors associated with faecal shedding of Campylobacter spp. A cohort of 133 heifers housed in four adjacent pens was examined over a five and a half month period, from entering the feedlot to slaughter. A parallel investigation of individual rectal faecal samples and pen environmental samples were taken at monthly intervals from November to February. The entire outer and inner surfaces of a carcass side of each animal were swabbed immediately following slaughter. Campylobacter spp. were isolated from 322 (54%) of the 600 rectal faecal samples. Campylobacter jejuni and C. coli accounted for 69 and 29.7% of the isolate recovered, respectively. A total of 159 environmental samples were examined, of these Campylobacter spp. was isolated from 46 samples (29%). Campylobacter jejuni and C. coli accounted for 35 and 59% of these isolates, respectively. Campylobacter spp. was not isolated from any of the dressed carcasses. Logistic regression indicated prevalence of Campylobacter spp. faecal shedding within pens was positively correlated to the pen, the month of sampling and the Campylobacter spp. contamination status of the pen dividing bars and the water trough surface. Campylobacter spp. should be considered as a pathogen shed in the faeces of a substantial proportion of feedlot cattle. However, with good hygienic practice during harvest, a very low level of this pathogen can be achieved on dressed carcasses.     

Antimicrobial resistance in generic fecal Escherichia coli obtained from beef cattle on arrival at the feedlot and prior to slaughter, and associations with volume of total individual cattle antimicrobial treatments in one western Canadian feedlot

A prospective observational study was carried out to examine antimicrobial resistance patterns of fecal Escherichia coli isolates of calves on arrival at the feedlot, and then evaluate the associations between the total volume of antimicrobial used for disease treatment and changes in antimicrobial resistance, during the feeding period. No macrolides or tetracyclines were administered in the feed during this study. On arrival, at the animal level, all 3 isolates obtained from 36.6% [95% confidence interval (CI): 29.0 to 44.8] of all cattle sampled (n = 153), were susceptible to all antimicrobials, while 5.9% (95% CI: 2.7 to 10.9) of cattle had at least 1 isolate that was resistant to ≥ 3 antimicrobials out of the 7 antimicrobials tested. The most frequent antimicrobials for which resistance was observed were sulphamethoxazole, ampicillin, and tetracycline where, of all cattle, 44.4% (95% CI: 36.4 to 52.7), 20.3% (95% CI: 14.2 to 27.5), and 17.7% (95% CI: 12.0 to 24.6), respectively had at least 1 resistant isolate. All cattle received antimicrobial metaphylaxis on arrival at the feedlot. Antimicrobial use was described for a cohort of 95 cattle. Antimicrobials were given to 42 of the 95 cattle during the feeding period, to treat disease. Amongst the 42 treated cattle, there were a total of 133 animal daily doses (ADD_Feedlot), where 1 ADD_Feedlot represented 1 day of antimicrobial treatment received by a feedlot animal at the approved dose. Only 1 ADD_Feedlot was given in the 100 days immediately prior to slaughter. There were no associations found between antimicrobial use and antimicrobial resistance in this study.     

Prevalence of thermophilic Campylobacter species in Swedish dogs and characterization of C. jejuni isolates

Background

The aims of this study were to investigate the prevalence of Campylobacter species in Swedish dogs, to identify the species of the Campylobacter isolates and to genotype the C. jejuni isolates. Young and healthy dogs were targeted and the sampling was performed at 11 veterinary clinics throughout Sweden from October 2011 to October 2012. Faecal swab samples were collected and sent to the laboratory at the National Veterinary Institute (SVA) for isolation of Campylobacter, speciation and genotyping.

Results

Campylobacter spp. were isolated from 67 of the 180 sampled dogs which yields an overall prevalence of 37%. The most prevalent species of Campylobacter among the participating dogs was C. upsaliensis with 52 of the 67 identified isolates. A lower prevalence was observed for C. jejuni with seven identified isolates and one isolate was identified as C. helveticus. Multi-locus sequence typing (MLST) was carried out on the seven C. jejuni isolates and all sequence types that were found are also commonly found in humans. The dogs were divided into three age groups; 1) under 12 months, 2) 12 to 23 months and 3) 24 months and older. The highest prevalence was found in the two younger age groups. Dogs shedding C. jejuni were between 3–12 months of age while dogs shedding C. upsaliensis were found in all ages.

Conclusions

The present investigation finds that Campylobacter spp. known to cause campylobacteriosis in humans are present in Swedish dogs. The results suggest an age predisposition where dogs under 2 years of age are more likely to shed Campylobacter spp. than older dogs. The most commonly isolated species was C. upsaliensis followed by C. jejuni, which was only detected in dogs up to 12 months of age. All C. jejuni isolates identified in the present study were of the same MLST types that have previously been described both in humans and in animals. The awareness of the Campylobacter risk of healthy young dogs may be an important way to reduce the transmission from dogs to infants, young children and immunocompromised adults.     

Prevalence,quantitative load and genetic diversity of Campylobacter spp. in dairy cattle herds in Lithuania

Background

Campylobacteriosis is a zoonotic disease, and animals such as poultry, pigs and cattle may act as reservoirs for Campylobacter spp. Cattle shed Campylobacter spp. into the environment and they can act as a reservoir for human infection directly via contact with cattle or their faeces or indirectly by consumption of contaminated food. The aim of this study was to determine the prevalence, the quantitative load and the genetic strain diversity of Campylobacter spp. in dairy cattle of different age groups.

Results

Faecal samples of 200 dairy cattle from three farms in the central part of Lithuania were collected and examined for Campylobacter. Cattle herds of all three farms were Campylobacter spp. positive, with a prevalence ranging from 75% (farm I), 77.5% (farm II) to 83.3% (farm III). Overall, the highest prevalence was detected in calves (86.5%) and heifers (86.2%). In contrast, the lowest Campylobacter prevalence was detectable in dairy cows (60.6%). C. jejuni, C. coli, C. lari and C. fetus subsp. fetus were identified in faecal samples of dairy cattle. C. upsaliensis was not detectable in any sample. The high counts of Campylobacter spp. were observed in faecal material of dairy cattle (average 4.5 log₁₀ cfu/g). The highest numbers of Campylobacter spp. were found in faecal samples from calves (average 5.3 log₁₀ cfu/g), whereas, faecal samples from cows harboured the lowest number of Campylobacter spp. (average 3.7 log₁₀ cfu/g). Genotyping by flaA PCR-RFLP analysis of selected C. jejuni isolates showed that some genotypes were present in all farms and all age groups. However, farm or age specific genotypes were also identified.

Conclusions

Future studies are needed to investigate risk factors related to the degree of colonisation in cattle. Based on that, possible measures to reduce the colonisation and subsequent shedding of Campylobacter in cattle could be established. It is important to further investigate the epidemiology of Campylobacter in the cattle population in order to assess associated risks to public health.     

Escherichia coli O157:H7 vaccine field trial in 9 feedlots in Alberta and Saskatchewan

A feedlot trial was conducted to assess the efficacy of an Escherichia coli O157:H7 vaccine in reducing fecal shedding of E. coli O157:H7 in 218 pens of feedlot cattle in 9 feedlots in Alberta and Saskatchewan. Pens of cattle were vaccinated once at arrival processing and again at reimplanting with either the E. coli O157:H7 vaccine or a placebo. The E. coli O157:H7 vaccine included 50 microg of type III secreted proteins. Fecal samples were collected from 30 fresh manure patties within each feedlot pen at arrival processing, revaccination at reimplanting, and within 2 wk of slaughter. The mean pen prevalence of E. coli O157:H7 in feces was 5.0%; ranging in pens from 0% to 90%, and varying significantly (P < 0.001) among feedlots. There was no significant association (P > 0.20) between vaccination and pen prevalence of fecal E. coli O157:H7 following initial vaccination, at reimplanting, or prior to slaughter.     

Occurrence of foodborne bacteria in Alberta feedlots

The occurrence of generic Escherichia coli, E. coli O157, Salmonella, and Campylobacter in cattle manure, beef carcasses, catch basin water, and soils receiving manure application was determined in 21 Alberta feedlots. In cattle manure, generic E. coli (98%, 2069/2100) and Campylobacter (76%, 1590/2100) were frequently detected; E. coli O157 (7%, 143/2100) and Salmonella (1%, 20/2100) were less frequently detected. Samples from beef carcasses in the cooler following Hazard Analysis Critical Control Point interventions yielded only 1 isolate each of generic E. coli and Campylobacter (1/1653) and no Salmonella (0/1653). Catch basin water specimens were positive for generic E. coli in both the spring (62%, 13/21) and the fall (52%, 11/21). Other bacteria were detected only in the spring water specimens, including E. coli O157 (29%, 6/21), Salmonella (5%, 1/21), and Campylobacter (52%, 11/21). Generic E. coli was frequently isolated from soil specimens (30%, 27/88), but E. coli O157 was not found in soil samples obtained in the spring and was only occasionally detected in the fall samples (9%, 3/32). Salmonella were occasionally found in the soil specimens collected in the spring (3%, 2/56), but not in the fall season (0/32). Campylobacter jejuni was frequent in cattle manure (66%, 1070/1623), but rare in carcass and environmental samples. E. coli O157 and Salmonella were rarely detected in cattle or the environment. Generic E. coli and Salmonella were rarely detected on carcasses.     

Antimicrobial resistances,and molecular typing of Campylobacter jejuni isolates,separated from food-producing animals and diarrhea patients in Iran

The aims of this study were to regain new epidemiology information about frequency, drug resistance rates, and typing of Campylobacter jejuni (C. jejuni) isolates, obtained from some poultry and cattle farms, slaughterhouses, and people with diarrhea. In this regard, Minimal Inhibitory Concentration (MIC) of several antibiotics and the associated antibiotic resistance genes, including tetO, tetA, cmeB, and bla_OXA-61 were evaluated. The isolates were also typed, using the Fla-RFLP method. Generally, between 233 food animal samples, 80 (34.33%) C. jejuni were isolated. Moreover, 20 out of 74 (27%) human specimens suspected to infectious diarrhea were C. jejuni positive. High frequencies of resistance to tetracycline (100%), ciprofloxacin (95%), and nalidixic acid (86%), and low frequencies of resistance to florfenicol (0%), erythromycin (5%), and gentamicin (8%) were observed. Furthermore, in the tetracycline-resistant isolates, the existences of tetO, tetA, and cmeB were 86%, 23%, and 48%, respectively. There was a significant correlation between the cluster types obtained from Fla-RFLP method and antibiotic resistance pattern. The results suggested that the genomic link between Campylobacter spp. should be always evaluated in each country to provide an insight about the Campylobacter spp., spread in the region, in order to implement the health-controlling programs efficiently.     

Meta‐analysis of the prevalence of thermotolerant Campylobacter in food‐producing animals worldwide

The objective of this meta‐analysis was to summarize available information on the prevalence of thermotolerant Campylobacter (TC) in different food‐producing animals worldwide. Databases (i.e., PubMed, ScienceDirect, Scopus) were searched from 1980 to 2017 unrestricted by language. The inclusion criteria were as follows: prevalence or incidence studies, published in peer‐reviewed journals, and they must have reported the total number of animal samples studied and the number of samples that were positive for the presence of TC. When the identification of Campylobacter species was available, this information was included in the analysis. Multilevel random‐effect meta‐analysis models were fitted to estimate mean occurrence rate of TC and to compare them among different factors potentially associated with the outcome. The mean occurrence rate of TC in food‐producing animals was 0.424 (95% CI: 0.394–0.455), and the mean occurrence rate of Campylobacter jejuni and Campylobacter coli were 0.214 and 0.133, respectively. Pigs and poultry showed the highest prevalence of TC; however, there were differences in the prevalence of each Campylobacter species. Campylobacter jejuni was observed in broilers (0.322; 95% CI: 0.273–0.377) and hens (0.395; 95% CI: 0.265–0.542), while C. coli was restricted essentially in pigs (0.553; 95% CI: 0.541–0.650). The prevalence of C. jejuni in intensively bred cattle was higher (0.302; 95% CI: 0.227–0.389) than the prevalence in extensively bred cattle (0.172; 95% CI: 0.119–0.242) while the prevalence of C. coli was similar (0.051; 95% CI: 0.028–0.091 vs. 0.050; 95% CI: 0.027–0.091) in both production systems. Agar with or without blood used for the isolation of TC did not affect the prevalence observed. The method of species identification did not seem to generate differences in the prevalence of Campylobacter species. The prevalence of Campylobacter in primary food production has a strong impact on the entire agri‐food chain. National authorities must monitor the situation with the aim to establish the appropriate risk management measures.     

An investigation of obligate and facultative anaerobes in bovine mastitis

Abstract

AIMS: To investigate the prevalence of Campylobacter spp. and C. jejuni in dog faecal material collected from dog walkways in the city of Palmerston North, New Zealand, and to characterise the C. jejuni isolates by multilocus sequence typing (MLST) and porA and flaA antigen gene typing.

METHODS: A total of 355 fresh samples of dogs faeces were collected from bins provided for the disposal of dog faeces in 10 walkways in Palmerston North, New Zealand, between August 2008–July 2009. Presumptive Campylobacter colonies, cultured on modified charcoal cefoperazone deoxycholate plates, were screened for genus Campylobacter and C. jejuni by PCR. The C. jejuni isolates were subsequently characterised by MLST and porA and flaA typing, and C. jejuni sequence types (ST) were assigned.

RESULTS: Of the 355 samples collected, 72 (20 (95% CI=16–25)%) were positive for Campylobacter spp. and 22 (6 (95% CI=4–9)%) were positive for C. jejuni. Of the 22 C. jejuni isolates, 19 were fully typed by MLST. Ten isolates were assigned to the clonal complex ST-45 and three to ST-52. The allelic combinations of ST-45/flaA 21/porA 44 (n=3), ST-45/flaA 22/porA 53 (n=3) and ST-52/ flaA 57/porA 905 (n=3) were most frequent.

CONCLUSIONS: The successful isolation of C. jejuni from canine faecal samples collected from faecal bins provides evidence that Campylobacter spp. may survive outside the host for at least several hours despite requiring fastidious growth conditions in culture. The results show that dogs carry C. jejuni genotypes (ST-45, ST-50, ST-52 and ST-696) that have been reported in human clinical cases.

CLINICAL RELEVANCE: Although these results do not provide any evidence either for the direction of infection or for dogs being a potential risk factor for human campylobacteriosis, dog owners are advised to practice good hygiene with respect to their pets to reduce potential exposure to infection.     

Mannheimia haemolytica in Feedlot Cattle: Prevalence of Recovery and Associations with Antimicrobial Use,Resistance, and Health Outcomes

Background

Mannheimia haemolytica is an important etiological agent in bovine respiratory disease.

Objectives

Explore risk factors for recovery of susceptible and resistant M. haemolytica in feedlot cattle and explore associations with health outcomes.

Animals

Cattle (n = 5,498) from 4 feedlots sampled at arrival and later in feeding period.

Methods

Susceptibility of M. haemolytica isolates tested for 21 antimicrobials. Records of antimicrobial use and health events analyzed using multivariable regression.

Results

M. haemolytica recovered from 29% of cattle (1,596/5,498), 13.1% at arrival (95% CI, 12.3–14.1%), and 19.8% at second sampling (95% CI, 18.7–20.9%). Nearly half of study cattle received antimicrobial drugs (AMDs) parenterally, mostly as metaphylactic treatment at arrival. Individual parenteral AMD exposures were associated with decreased recovery of M. haemolytica (OR, 0.2; 95% CI, 0.02–1.2), whereas exposure in penmates was associated with increased recovery (OR, 1.5; 95% CI, 1.05–2.2). Most isolates were pan‐susceptible (87.8%; 95% CI, 87.0–89.4%). AMD exposures were not associated with resistance to any single drug. Multiply‐resistant isolates were rare (5.9%; 95% CI, 5.1–6.9%), but AMD exposures in pen mates were associated with increased odds of recovering multiply‐resistant M. haemolytica (OR, 23.9; 95% CI, 8.4–68.3). Cattle positive for M. haemolytica on arrival were more likely to become ill within 10 days (OR, 1.7; 95% CI, 1.1–2.4).

Conclusions and Clinical Importance

Resistance generally was rare in M. haemolytica. Antimicrobial drug exposures in penmates increased the risk of isolating susceptible and multiply‐resistant M. haemolytica, a finding that could be explained by contagious spread.     

Phenotypic and Genotypic Anti‐Microbial Resistance Profiles of Campylobacters from Untreated Feedlot Cattle and Their Environment

Anti‐microbial resistance is an emerging public health issue. Farmed animals may act as reservoirs and potential sources of anti‐microbial resistant Campylobacters. The aim of this study was to investigate the anti‐microbial resistance profile of cattle and environmental Campylobacter isolates from normal untreated feedlot cattle, the role of the gyrA Thr‐86‐Ile mutation in ciprofloxacin‐resistant Campylobacter jejuni isolates and the involvement of the tripartite CmeABC efflux system for multi‐resistant C. jejuni isolates. The phenotypic anti‐microbial resistance testing was carried out on 500 Campylobacter isolates (445 cattle isolates and 55 environmental isolates). In general, there was a higher level of anti‐microbial resistance for the environmental isolates compared with the animal isolates, 45% of the animal isolates were resistant to one or more of the seven anti‐microbials compared with 84% of the environmental isolates. The combined cattle and environmental Campylobacters had 34 (6.8%) isolates resistant to three or more of the seven anti‐microbials tested on all isolates and 11 (2.2%) isolates were resistant to the seven anti‐microbials. There was a substantial level of ciprofloxacin‐resistant Campylobacters in both animal (8.5%) and environmental (21.8%) isolates. The gyrA Thr‐86‐Ile mutation was only present in five of 22 ciprofloxacin‐resistant C. jejuni isolates investigated. No multi‐drug‐resistant associated mutation was detected in the CmeB or the CmeR regions investigated. In conclusion, our study observed a substantial level of Campylobacter anti‐microbial resistance, highlighting the need for an active anti‐microbial surveillance program for food animals in Ireland and the importance of the chosen sampling point can have on the findings of such a program.     

Molecular detection of Campylobacter species and Cytolethal distending toxin isolated from chicken livers in Tabriz

Introduction and purpose: Campylobacter jejuni and coli are zoonotic bacteria commonly associated With human diarrhea and usually transmit through consumption of meat and poultry contaminated products such as heart and liver. Cytolethal distending toxin (cdt) in Campylobacter spp. is among the significant virulence factors of these bacteria in the intestine. The purpose of this study was to determine the prevalence of Campylobacter spp. and presence of cdt genes among isolated bacteria. Materials and methods: In this cross sectional study, 100 chicken livers were examined. Detection, bacterial enumeration and isolation of Campylobacter spp. was done using Campylobacter selective agar media containing Campylobacter growth supplement, gram staining, catalase and oxidase production, hippurate hydrolysis and PCR molecular technique. Also the presence of cdt genes were detected using PCR assay. Results: From 100 studied liver samples, 43 were contaminated with Campylobacter spp. Among them 31(72 %) samples had Campylobacter jejuni and 12 (28 %) had Campylobacter coli. All Campylobacter jejuni isolates contained cdtA ،cdtB and cdtC genes. However, all of these genes detected in 9 (75 %) of isolated coli. Conclusion: The results of this study showed that great percentages of chicken livers in Tabriz were contaminated with Campylobacter.     

Determination of the seroprevalence of Neospora caninum in feedlot steers in Alberta

A study was conducted in Alberta to determine the seroprevalence of Neospora caninum in feedlot calves purchased from various auction markets throughout western Canada. Four feedlots (1 feedlot from each of the Airdrie and High River areas and 2 feedlots from the Strathmore area) were selected for sampling. At each feedlot, a random 10% sample of feedlot steer and bull calves entering the feedlot from September 2001 to December 2001 were enrolled in the study until there were a maximum of 500 animals enrolled per feedlot. Blood samples were collected from 1976 male animals at the time of entry to the 4 study feedlots. The animals represented 375 groups purchased from 70 sale points throughout British Columbia, Alberta, Saskatchewan, and Manitoba. Of the 1976 animals tested, 128 animals tested positive for antibodies to N. caninum. The prevalence and adjusted 95% confidence limits for N. caninum in beef calves on entrance to the feedlot in western Canada were 6.5% (95% CI, 5.1 to 8.2). There were no significant (P > or = 0.05) associations between the risk of treatment, the risk of designation as "chronic," and the risk of death and antibodies to N. caninum either before or after adjusting for feedlot, entry weight, entry date, and clustering of disease within lots at each feedlot. In addition, there was no significant (P > or = 0.05) association between serological status and feedlot entry weight or average daily gain. Note that there was no information available on feed conversion because the calves were mixed within existing commercial feedlot pens and the actual feed intake of each animal could not be determined. Adjustment for the concentration of antibodies to bovine viral diarrhea virus on arrival did not change any of the examined associations between N. caninum status and calf health or performance. The results of this study demonstrated that the prevalence of N. caninum in feedlot calves in western Canada was less than the prevalence reported in the United States. Additional studies are required to determine whether the inferior rate of gain and feed efficiency observed in the southern United States with animals testing positive for antibodies to N. caninum also occurs under the management conditions used in western Canada.     

Molecular and Statistical Analysis of Campylobacter spp. and Antimicrobial‐Resistant Campylobacter Carriage in Wildlife and Livestock from Ontario Farms

The objectives of this study were to (i) compare the carriage of Campylobacter and antimicrobial‐resistant Campylobacter among livestock and mammalian wildlife on Ontario farms, and (ii) investigate the potential sharing of Campylobacter subtypes between livestock and wildlife. Using data collected from a cross‐sectional study of 25 farms in 2010, we assessed associations, using mixed logistic regression models, between Campylobacter and antimicrobial‐resistant Campylobacter carriage and the following explanatory variables: animal species (beef, dairy, swine, raccoon, other), farm type (swine, beef, dairy), type of sample (livestock or wildlife) and Campylobacter species (jejuni, coli, other). Models included a random effect to account for clustering by farm where samples were collected. Samples were subtyped using a Campylobacter‐specific 40 gene comparative fingerprinting assay. A total of 92 livestock and 107 wildlife faecal samples were collected, and 72% and 27% tested positive for Campylobacter, respectively. Pooled faecal samples from livestock were significantly more likely to test positive for Campylobacter than wildlife samples. Relative to dairy cattle, pig samples were at significantly increased odds of testing positive for Campylobacter. The odds of isolating Campylobacter jejuni from beef cattle samples were significantly greater compared to dairy cattle and raccoon samples. Fifty unique subtypes of Campylobacter were identified, and only one subtype was found in both wildlife and livestock samples. Livestock Campylobacter isolates were significantly more likely to exhibit antimicrobial resistance (AMR) compared to wildlife Campylobacter isolates. Campylobacter jejuni was more likely to exhibit AMR when compared to C. coli. However, C. jejuni isolates were only resistant to tetracycline, and C.  coli isolates exhibited multidrug resistance patterns. Based on differences in prevalence of Campylobacter spp. and resistant Campylobacter between livestock and wildlife samples, and the lack of similarity in molecular subtypes and AMR patterns, we concluded that the sharing of Campylobacter species between livestock and mammalian wildlife was uncommon.     

Presence of non-O157 Shiga toxin-producing Escherichia coli in feces from feedlot cattle in Alberta and absence on corresponding beef carcasses.

The study objectives were to determine the prevalence and serotypes of non-O157 Shiga toxin-producing Escherichia coli (STEC) in pens of feedlot cattle and on corresponding beef carcasses. We collected 25 fecal samples from 84 pens in 21 Alberta feedlots and 40 carcass swabs from each preslaughter pen for analysis by culture and polymerase chain reaction (PCR). Non-O157 STEC were recovered from feces from 12 (14%) of the 84 pens and 12 (57%) of the 21 feedlots by examination of 1 E. coli isolate positive for 4-methylumbelliferyl-beta-beta-glucuronide per sample. Twelve non-O157 serotypes were detected, but 7 of the 15 STEC isolates lacked the accessory virulence genes eae and hlyA. Although 115 (7%) of the carcass broths were PCR-positive, no STEC isolates were recovered from the 1650 carcasses sampled. Our data indicate that multiple non-O157 STEC serotypes may be present in cattle feces, yet are unlikely to be recovered from the corresponding beef carcasses when 20 colonies per sample from PCR-positive broth cultures are analyzed.     

Distribution of bovine cysticercosis in Washington

Data from slaughter plants (n = 3) and feedlots (n = 18) in eastern Washington were analyzed to characterize occurrence patterns of cysticercosis in Washington during 1984. Three concurrent peaks in cysticercosis rates (0.6/1,000 to 5/1,000 slaughtered cattle) were detected at 3 slaughter plants. Peaks were observed at 8 feedlots from December 1983 to March 1984, at 6 feedlots from April to July 1984, at 2 feedlots from August to October 1984, and at 3 feedlots from November 1984 to February 1985. Affected feedlots were not closely associated geographically and were feeding cattle from many, predominantly northwestern, origins. For 3 feedlots for which time in the feedlot was available for each slaughter shipment, an increase in cysticercosis rate with increasing time in the feedlot was noticed. Within these 3 feedlots, cases of cysticercosis were widely scattered spatially. The pattern of cysticercosis indicated human fecal contamination of a regionally available feed source. Of feedstuffs in use, potato waste, a byproduct of the processed potato industry, appeared to be the most likely source of Taenia saginata ova.     

Prevalence and antibiotic susceptibility of thermophilic Campylobacter isolates from free range domestic duck (Cairina moschata) in Morogoro municipality, Tanzania

Prevalence and antibiotic susceptibility of thermophilic Campylobacter isolated from free-ranging ducks was determined in Morogoro Municipality, Tanzania. Ninety intestinal contents from ducks were screened for thermophilic Campylobacter using Skirrow’s protocol. Of the Campylobacter jejuni isolates, 50 were tested for sensitivity to 12 antibiotics. Overall prevalence of thermophilic Campylobacter was 80%. The prevalence of Campylobacter in adult ducks (91.3%) was significantly (p?<?0.05) higher than ducklings (68.2%). The isolation rate of C. jejuni (81.9%) was significantly (P?<?0.001) higher than C. coli (18.1%). All C. jejuni isolates were susceptible to streptomycin, nitrofurantoin and amikacin. Forty eight percent, 74% and 82% of isolates were resistant to cefuroxime sodium, tetracycline and ampicillin respectively. Between 20–50% of isolates were resistant to erythromycin, gentamicin, cloxacillin and amoxicillin. Norfloxacin and ciprofloxacin had lower C. jejuni resistance of 10% and 16% respectively. C. jejuni isolates from adult ducks showed significantly higher rates of resistance (p?<?0.05) to most antibiotics than did duckling isolates. High prevalence of thermophilic Campylobacter in ducks could be of public health significance in Morogoro municipality. The observed multidrug resistance in this study poses a threat of transfer of antibiotic resistance to human pathogens because of the close contact between ducks and human.     

Potomac horse fever in Ontario: Clinical,geographic, and diagnostic aspects

Clinical findings, geographic locations, laboratory diagnoses, and culture isolation of Neorickettsia spp. in Potomac horse fever (PHF) cases diagnosed in Ontario between 2015 and 2019 are described. Forty-six confirmed PHF cases occurred from late June to early September. Of 41 horses admitted to the Ontario Veterinary College, 28 (68%) survived and 13 (32%) were euthanized due to poor prognosis or financial constraints. Most cases were in southern Ontario along the Canada-USA border. Blood and fecal samples from 43 suspect PHF cases were submitted to 2 laboratories for polymerase chain reaction (PCR) testing for Neorickettsia risticii. Agreement between both laboratories for detection of N. risticii DNA was excellent for feces [κ = 0.932, 95% confidence interval (CI): 0.80 to 1], and fair for blood samples (κ = 0.494, 95% CI: 0.13 to 0.85). Neorickettia spp. were isolated from 16 of 41 (39%) blood samples. DNA analysis confirmed 14 isolates were N. risticii and 2 were N. findlayensis, a novel species of Neorickettsia recently demonstrated to cause PHF.     

Herd-level risk factors associated with fecal shedding of Shiga toxin-encoding bacteria on dairy farms in Minnesota,USA

This study aimed to identify herd-level risk factors associated with fecal shedding of Shiga toxin-encoding bacteria (STB) on dairy cattle farms in Minnesota, USA. After adjustment for farm size, risk factors included: use of total mixed ration (TMR) for lactating dairy cows [odds ratio (OR) = 3.0; 95% confidence interval (CI): 1.8 to 5.1], no use of monensin for weaned calves (OR = 4.8, 95% CI: 2.5, 9.3), and no use of decoquinate for preweaned calves (OR = 2.2, 95% CI: 1.4, 3.6). Fecal shedding of STB was more common in small herds (< 100 cows, OR = 3.6, 95% CI: 2.1, 6.2) than in large herds (≥ 100 cows). Herd management factors related to cattle feeding practices were associated with fecal shedding of STB.     

Management and nutritional factors associated with the detection of Salmonella sp. from cattle fecal specimens from feedlot operations in the United States

In a convenience sample of 100 feedlot operations (included in the United States Department of Agriculture: Animal and Plant Health Inspection Service 1994 Cattle on Feed Evaluation), up to 25 cattle fecal samples were collected and tested for the presence of Salmonella from each of two pens (the pen which contained the most-recent arrivals, and the pen with cattle that had been on feed the longest). One or more Salmonella spp. were recovered from 38 (38.0%) of the 100 feedlots, 52 (26.0%) of the 200 pens and 273 (5.5%) of the 4977 fecal samples collected. Multivariable logistic regression indicated that feeding tallow and feeding whole cottonseed or cottonseed hulls within seven days prior to fecal sample collection was associated with an increased risk of finding Salmonella in a pen. Variables not found to be significantly associated with the detection of Salmonella in a pen included region, operation size, use of sprinklers, time on feed, type of cattle in the pen, number and concentration of cattle in a pen, feeding probiotics, and various other feeds.