Shiga toxin (stx) encoding genes in sheep and goats reared in Trinidad and Tobago.

Shiga toxin-producing Escherichia coli (STEC) is estimated to cause over two million cases of human disease annually. Trinidad and Tobago is one of the largest livestock producer and consumer of sheep and goat meat in the Caribbean, however, the potential role of these animals in the epidemiology of STEC infections has not been previously described. To fill this critical gap in knowledge, the prevalence of Shiga toxin genes (stx1 and stx2) shed in the faeces of healthy sheep (n = 204) and goats (n = 105) in Trinidad was investigated. Based on PCR screening, goats had a higher stx prevalence than sheep (46% vs 35%, P = 0.06). Most of the recovered STEC isolates were positive for stx1 only; and only three isolates were positive for the eae gene. None of the recovered isolates belonged to the O157 serogroup. In both species, the prevalence of stx was higher in young animals versus older animals. Sheep reared on deep litter flooring (43%) had a higher prevalence than sheep reared other flooring types, however this was not the same for goats. The presence of cows on the same premise was not an associated predictor for STEC carriage in sheep or goats. This study demonstrates that although sheep and goats in Trinidad are reservoirs for stx-positive E. coli isolates, no fecal samples tested positive for O157 STEC, harbored. Furthermore, it appears that non-O157 stx-positive isolates harbored by these animals do not pose a significant threat to human health.

Identification and Subtyping of Salmonella Isolates Using Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF).

Subtyping of bacterial isolates of the same genus and species is an important tool in epidemiological investigations. A number of phenotypic and genotypic subtyping methods are available; however, most of these methods are labor-intensive and time-consuming and require considerable operator skill and a wealth of reagents. Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF), an alternative to conventional subtyping methods, offers a rapid, reproducible method for bacterial identification with a high sensitivity and specificity and at minimal cost. The purpose of this study was to determine the feasibility of using MALDI-TOF to differentiate between six Salmonella serovars recovered from experimental microcosms inoculated with known strains of Salmonella. Following the establishment of a MALDI-TOF reference library for this project, the identity of 843 Salmonella isolates recovered from these microcosms was assessed using both MALDI-TOF and conventional methods (serotyping/PCR). All 843 isolates were identified as being Salmonella species. Overall, 803/843 (95%) of these isolates were identified similarly using the two different methods. Positive percent agreement at the serovar level ranged from 79 to 100%, and negative percent agreement for all serovars was greater than 98%. Cohen's kappa ranged from 0.85 to 0.98 for the different serovars. This study demonstrates that MALDI-TOF is a viable alternative for the rapid identification and differentiation of Salmonella serovars.

Diaphyseal nutrient foramina in the humerus, radius, femur, and tibia bones of mixed breed dogs.

OBJECTIVE: The objective of this study was to determine the location, number, and direction of the nutrient foramen in the humerus, radius, femur, and tibia bones of mixed breed dogs. MATERIALS AND METHODS: The humerus, radius, femur, and tibia of both (left and right) limbs of mixed breed dogs were examined in this study. The number, location, and direction of the nutrient foramina were identified. Once identified, the diameter of each nutrient foramen was measured and the site index calculated. RESULTS: Only one nutrient foramen was identified in the humerus, radius, tibia, and right femur, while the foramen numbers ranged from one to three in the left femurs examinated. The nutrient foramen was localized on the caudal surface in the radii, femurs, tibias, and left humeri. Contrasting, however, 75% were located on the caudal surface of the right humeri and 25% on the lateral surface. The average diameter of the nutrient foramen of the humerus ranged from 0.88 to 1.00 mm, while it ranged from 1.13 to 1.25 mm in the radius. On the hind limb, the diameter of the nutrient foramen on the femur ranged from 1.2 to 1.3 mm and 0.75-1.25 mm on the tibia. The nutrient foramen was directed towards the corresponding joint in 100% of the humeri and tibias, 75% of the radii, and 60%-80% of the femurs examined. CONCLUSION: The anatomical data on the nutrient foramen obtained in this study will be valuable for veterinarians when diagnosing pathological bone lesions and for orthopedic surgery.

A Case Report of A Urinary Bladder Marsupializatiojm to correct Obstructive Urolithiasis in a 3-Month-Old Boer Goat (Capra hircus)

A 3-month-old intact male Boer caprine kid weighing 22.3Kg. presented to the Large Animal Hospital, School of Veterinary Medicine (SVM), with a primary complaint of stranguria for approximately 8 days. The animal had been treated one week prior to presentation by a private clinician who amputated the vermiform appendage which offered temporary resolution of the clinical signs. Within twodays however, the animal was once again observed with stranguria and the clinician referrred the animal to the SVM for further treatment. On presentation, the patient had multiple anomalies including, paraphimosis. a swelling at the base of the penile shaft and tachycardia. Radiographic examination revealed a distended bladder. No radio-opaque calculi were noted along the urethra. The patient required urgent surgical intervention during which he was maintained under anaesthesia using continuous rate indusion of ketamine and lidocaine to which xylazine was subsequently added after a cystotomy was performed. The patient recovered with minimal post-operative complications. Although not a common procedure in farm animals due to its aftercare, bladder marsupialization was deemed feaseible in this case since the patient was reared with some sentimental value rather than entirely for production. This procedure shpuld thus be considered for pet livestock animals or in salvage situations where a perineal urethrostomy is deemed non-curative,

A Case Report of A Hybrid External Fixator for Fracture Repair in a 3-Month-Old Boer Goat (Capra hircus)

A 3-month-old male intact crossbred Boer Anglo Nubian caprine kid weighing 20.50Kg. presented to the School of Veterinary Medicine (SVM) with a history of acute onset lameness of the left hind limb. Initial examination at a private veterinary clinic revealed a fracture of the left tibia. The patient was referred to the SVM for treatment. Physical and radiographic examination of the animal revealed a closed, complete, short oblique fracture of the distal metaphysis of the left tibia with moderate cranio-proximal displacemnt of the distal segment, The limb was temporarily immobilized using a pre-made bivalve cast until the surgery. Surgical intervention involved using hybrid external fixator best described as a maximal bilateral uniplanar (Type II) fixator frame with a distal fabricated aluminum ring. The post-operative regimen included antibiotics, non-steroidal anti-inflammatories, frequent cleaning of the pin-skin interface and apparatus bandage changes, The animal was also confined to pen rest initially with gradual increase in exercise. Since surgery, the patient has progressively increases weight bearing on the affected limb and was fully weight bearing upon external fixator removal, 6-weeks post operatively. This method of external fixatiojm has not been commonly used foe repair of fractured limbs in goats, however in this scenario it proved ecomonical and highly effectively in provideing the stability required for fracture repair. Veterarians with limited resourcs and financially conservative clients should consider this method for repairing similar type fractures in small ruminant animal species.

Survival of Shiga Toxin-Producing Escherichia coli in Various Wild Animal Feces That May Contaminate Produce.

ABSTRACT: Domestic and wild animal intrusions are identified as a food safety risk during fresh produce production. The purpose of this study was to evaluate the survival of Shiga toxin-producing Escherichia coli (STEC) in cattle, feral pig, waterfowl, deer, and raccoon feces from sources in California, Delaware, Florida, and Ohio. Fecal samples were inoculated with a cocktail of rifampin-resistant STEC serotypes (O103, O104, O111, O145, and O157) (104 to 106 CFU/g of feces). Inoculated feces were held at ambient temperature. Populations of surviving cells were monitored throughout 1 year (364 days), with viable populations being enumerated by spread plating and enrichment when the bacteria were no longer detected by plating. Representative colonies were collected at various time intervals based on availability from different locations to determine the persistence of surviving STEC serotypes. Over the 364-day storage period, similar survival trends were observed for each type of animal feces from all states except for cattle and deer feces from Ohio. STEC populations remained the highest in cattle and deer feces from all states between days 28 and 364, except for those from Ohio. Feral pig, waterfowl, and raccoon feces had populations of STEC of <1.0 log CFU/g starting from day 112 in feces from all states. E. coli O103 and O104 were the predominant serotypes throughout the entire storage period in feces from all animals and from all states. The survival of both O157 and non-O157 STEC strains in domesticated and wild animal feces indicates a potential risk of contamination from animal intrusion.

Survival of Salmonella in Various Wild Animal Feces That May Contaminate Produce.

ABSTRACT: Heightened concerns about wildlife on produce farms and possible introduction of pathogens to the food supply have resulted in required actions following intrusion events. The purpose of this study was to evaluate the survival of Salmonella in feces from cattle and various wild animals (feral pigs, waterfowl, deer, and raccoons) in California, Delaware, Florida, and Ohio. Feces were inoculated with rifampin-resistant Salmonella enterica cocktails that included six serotypes: Typhimurium, Montevideo, Anatum, Javiana, Braenderup, and Newport (104 to 106 CFU/g). Fecal samples were stored at ambient temperature. Populations were enumerated for up to 1 year (364 days) by spread plating onto tryptic soy agar supplemented with rifampin. When no colonies were detected, samples were enriched. Colonies were banked on various sampling days based on availability of serotyping in each state. During the 364-day storage period, Salmonella populations decreased to ≤2.0 log CFU/g by day 84 in pig, waterfowl, and raccoon feces from all states. Salmonella populations in cattle and deer feces were 3.3 to 6.1 log CFU/g on day 336 or 364; however, in Ohio Salmonella was not detected after 120 days. Salmonella serotypes Anatum, Braenderup, and Javiana were the predominant serotypes throughout the storage period in all animal feces and states. Determination of appropriate risk mitigation strategies following animal intrusions can improve our understanding of pathogen survival in animal feces.

A Review of Current Research and Knowledge Gaps in the Epidemiology of Shiga Toxin-Producing Escherichia coli and Salmonella spp. in Trinidad and Tobago.

Salmonella and Shiga toxin-producing Escherichia coli are two of the main causes of foodborne disease globally, and while they have been implicated as possible causes of foodborne disease within the Caribbean region, the actual incidence is unknown. Trinidad and Tobago, one of the larger countries in the Caribbean, has an estimated annual foodborne disease burden of over 100,000 cases and, similar to other countries, the etiology of most of these cases is unknown. Both pathogens can reside as part of the normal gastrointestinal microflora of many wild and domestic animals, with animals acting as reservoirs, spillover hosts, or dead-end hosts. Carriage in animal species can be asymptomatic or, in the case of Salmonella in particular, there may be clinical manifestation in animals, which resemble the disease seen in humans. In this review, we will focus on the epidemiology of these two foodborne pathogens in Trinidad and Tobago and identify any knowledge gaps in the published literature. The filling of this critical knowledge void is essential for the development and implementation of appropriate mechanisms to reduce the dissemination and transmission of these pathogens, not only in Trinidad and Tobago, but also in the wider Caribbean.

Rapid loss of a green fluorescent plasmid in Escherichia coli O157:H7.

Plasmids encoding green fluorescent protein (GFP) are frequently used to label bacteria, allowing the identification and differentiation from background flora during experimental studies. Because of its common use in survival studies of the foodborne pathogen Escherichia coli O157:H7, it is important to know the extent to which the plasmid is retained in this host system. Herein, the stability of a pGFPuv (Clontech Laboratories Inc) plasmid in six Escherichia coli O157:H7 isolates was assessed in an oligotrophic environment (phosphate buffered saline, PBS) without antibiotic selective pressure. The six test isolates were recovered from a variety of animal and human sources (cattle, sheep, starlings, water buffalo, and human feces). GFP labeling of the bacteria was accomplished via transfer electroporation. The stability of the GFP plasmid in the different E. coli O157:H7 isolates was variable: in one strain, GFP plasmid loss was rapid, as early as one day and complete plasmid loss was exhibited by four of the six strains within 19 days. In one of the two isolates retaining the GFP plasmid beyond 19 days, counts of GFP-labeled E. coli O157:H7 were significantly lower than the total cell population (P < 0.001). In contrast, in the other isolate after 19 days, total E. coli O157:H7 counts and GFP-labeled E. coli counts were equivalent. These results demonstrate strain-to-strain variability in plasmid stability. Consequently the use of GFP-labeled E.coli O157:H7 in prolonged survival studies may result in the underestimation of survival time due to plasmid loss.

Animal Reservoirs of Shiga Toxin-Producing Escherichia coli.

Shiga toxin-producing Escherichia coli (STEC) strains have been detected in a wide diversity of mammals, birds, fish, and several insects. Carriage by most animals is asymptomatic, thus allowing for dissemination of the bacterium in the environment without detection. Replication of the organism may occur in the gastrointestinal tract of some animals, notably ruminants. Carriage may also be passive or transient, without significant amplification of bacterial numbers while in the animal host. Animals may be classified as reservoir species, spillover hosts, or dead-end hosts. This classification is based on the animal's ability to (i) transmit STEC to other animal species and (ii) maintain STEC infection in the absence of continuous exposure. Animal reservoirs are able to maintain STEC infections in the absence of continuous STEC exposure and transmit infection to other species. Spillover hosts, although capable of transmitting STEC to other animals, are unable to maintain infection in the absence of repeated exposure. The large diversity of reservoir and spillover host species and the survival of the organism in environmental niches result in complex pathways of transmission that are difficult to interrupt.