Research Articles (Production Animal Studies)

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Antimicrobial resistance profiles of Listeria species recovered from retail outlets in Gauteng Province, South Africa
(Elsevier, 2024-08) Gana, James; Gcebe, Nomakorinte; Moerane, Rebone; Ngoshe, Yusuf Bitrus; Tshuma, Tsakula; Moabelo, Khomotso C.; Adesiyun, Abiodun Adewale; abiodun.adesiyun@up.ac.za
The study determined the antimicrobial resistance (AMR) profiles of Listeria spp. (L. monocytogenes, L. innocua, and L. welshimeri) recovered from beef and beef products sold at retail outlets in Gauteng Province, South Africa. A total of 112 isolates of Listeria spp., including L. monocytogenes (37), L. innocua (65), and L. welshimeri (10), were recovered from beef and beef products collected from 48 retail outlets. Listeria spp. was recovered by direct selective plating following selective enrichment, and PCR was used to confirm and characterize recovered isolates. The disc diffusion method determined the resistance to 16 antimicrobial agents. All 112 isolates of Listeria spp. exhibited resistance to one or more antibiotics (P < 0.05). The prevalence of AMR in Listeria isolates was high for nalidixic acid (99.1%) and cefotaxime (80.4%) but low for gentamycin (2.7%), sulfamethoxazole‐trimethoprim (3.6%), azithromycin (5.4%), and doxycycline (6.3%). Overall, for the three species of Listeria, the prevalence of resistance varied significantly only for streptomycin (P=0.016) and tetracycline (P = 0.034). Multidrug‐resistant isolates were detected in 75.7% (28/37), 61.5% (40/65), and 80% (8/10) isolates of L. monocytogenes, L. innocua, and L. welshimeri, respectively. The prevalence of AMR was significantly affected by the location and size of retail outlets, type of beef and beef products, and serogroups of L. monocytogenes. The high prevalence of AMR, particularly among the L. monocytogenes isolates, poses potential therapeutic implications for human consumers of contaminated beef products. There is, therefore, a need to regulate and enforce the use of antimicrobial agents in humans and animals in South Africa.
Molecular characterization of virulence and resistance genes in Salmonella strains isolated from chickens sold at the informal chicken market in Gauteng Province, South Africa
(Wiley, 2024-04) Mokgophi, Thelma M.; Gcebe, Nomakorinte; Fasina, Folorunso Oludayo; Adesiyun, Abiodun Adewale
This cross-sectional study determined the occurrence of virulence and antimicrobial resistance genes in Salmonella strains recovered from chicken obtained from informal markets in Gauteng province, South Africa. The study also assessed the relationship between these characteristics, the source, the type of samples, and the serotypes of Salmonella isolates. A total of 151 samples (cloacal swabs, chicken carcasses, and carcass drips) were randomly collected from 47 informal market outlets in six townships in Gauteng province. Salmonella spp. was isolated and identified based on ISO 6579:2002 methods and confirmed by polymerase chain reaction (PCR) targeting invA gene fragment. Conventional PCR was used to detect 12 virulence and 18 antimicrobial resistance (AMR) genes in Salmonella spp. The most frequently detected virulence genes were invA (100%), shdA (91%), mgtB (87.7%), and sopE (81%), but considerably low for spvC (2.2%), sefC (1.5%), and pefC (0.4%). The differences in detection frequency were statistically significant (p < 0.05). Tetracycline-resistant genes tetA (34.7%) and tetB (16%) were the most frequently detected, while Betalactam- resistant genes blaTEM (0.4%), blaCMY-2 (0.4%) and quinolones resistant gene qnrS (0.4%) were detected in low frequency (p < 0.05). The locations of the outlets and the types of samples were significantly associated with detecting some virulence and AMR genes. Significant but moderately to substantial positive correlations were observed for qnrS, sul2; shdA, and mgtB genes. The pipA and spiC were, however, substantially negatively correlated. Our findings show that detecting these virulence and AMR genes in Salmonella isolates serves as a potential health hazard to the public, environment, and poultry farming in Gauteng, South Africa.
Closed laceration of the trachea, esophagus and guttural pouches in a mare caused by blunt trauma
(Elsevier, 2024-12) Lopes, M.A.F.; Hollenbach, Elza; Schliewert, Eva-Christina; Murphy, Mark-Anthony; Correa, Felipe
A mare was admitted for progressive swelling of the neck, lethargy and anorexia. Radiography revealed perilaryngeal, peritracheal, and periesophageal emphysema. Endoscopy revealed pharyngeal and tracheal roof collapse, and a small laceration on the trachea. Treatment with antimicrobials, fluids, and flunixin was initiated. To prevent exacerbation of the emphysema, temporary tracheostomy was performed. Clipping for the tracheostomy revealed a hoofprint mark on the ventral neck. Subsequent endoscopies revealed laceration of the esophagus and guttural pouch septum communicating with the visceral compartment of the neck. Four days after admission, an esophagostomy was performed to prevent leakage of ingesta into the neck and allow feeding. Complications occurred: Deep cervical infection requiring surgical drainage; Esophageal impaction with shavings on one occasion causing extensive mucosa erosions; Laminitis managed with restricted physical activity and corrective farriery. Tracheostomy tube removal, esophagostomy tube removal, and patient discharge occurred 10, 36 and 51 days after admission, respectively. The mare did well after discharge and returned to competing in children’s showing classes. Blunt trauma to the neck can lacerate the trachea, esophagus and guttural pouches causing emphysema and deep cervical infection, which can be treated with antimicrobials, temporary tracheostomy, temporary esophagostomy, surgical drainage, and supportive care.
Evidence for horizontal transmission and recirculation of Shiga toxin-producing Escherichia coli in the beef production chain in South Africa using whole genome sequencing
(MDPI, 2024-09) Onyeka, L.O. (Libby); Adesiyun, Abiodun Adewale; Ismail, Arshad; Allam, Mushal; Keddy, Karen H.; Thompson, P.N. (Peter N.); peter.thompson@up.ac.za
Please read abstract in article.
Brucellosis seropositivity using three serological tests and associated risk factors in abattoir workers in Gauteng province, South Africa
(MDPI, 2024-01) Kolo, Francis Babaman; Adesiyun, Abiodun Adewale; Fasina, Folorunso Oludayo; Harris, Bernice Nerine; Rossouw, Jennifer; Byaruhanga, Charles; De Wet Geyer, Hermanus; Blumberg, Lucille; Frean, John; Van Heerden, Henriette
Abattoir workers are liable to zoonotic infections from animals and animal products, primarily to diseases with asymptomatic and chronic clinical manifestations in animals, such as brucellosis. No published reports exist on the seroprevalence of brucellosis in abattoir workers in South Africa. Therefore, this cross-sectional study was conducted to estimate the occurrence and risk factors for Brucella exposure in abattoir workers in Gauteng Province. A total of 103 abattoir workers and managers from 6 abattoirs, where brucellosis-positive slaughtered cattle and sheep were previously detected, were interviewed and tested with serological assays using the Rose Bengal test (RBT), BrucellaCapt, and IgG-ELISA. A pre-tested questionnaire was administered to consenting respondents to obtain information on risk factors for brucellosis. Of the 103 respondents tested, the distribution of female and male workers was 16 (15.5%) and 87 (84.5%), respectively. The seroprevalence for exposure to brucellosis was 21/103 (20.4%, 95%CI: 13.1–29.5) using a combination of RBT, BrucellaCapt, or IgG-ELISA. For test-specific results, seroprevalences by RBT, BrucellaCapt, and IgG-ELISA were 13/103 (12.6%, 95%CI: 6.9–20.6), 9/103 (8.74%, 95%CI: 4.1–15.9), and 18/103 (17.5%, 95%CI: 10.7–26.2), respectively. Low-throughput abattoirs were identified as associated risks, as 29.3% of workers were seropositive compared with 12.7% of workers in high-throughput abattoirs, which highlights that direct contact at abattoirs poses higher risk to workers than indirect and direct contact outside abattoirs. This study confirms the occurrence of Brucella spp. antibodies among abattoir workers in South Africa, possibly due to occupational exposure to Brucella spp., and highlights the occupational hazard to workers. Furthermore, findings underscore that abattoir facilities can serve as points for active and passive surveillance for indicators of diseases of public health importance. We recommend periodic implementation of brucellosis testing of abattoir workers country-wide to establish baseline data for informing appropriate preventive practices and reducing the potential burden of infection rates among these high-risk workers.
Influence of tannin-rich extract from commercial Acacia mearnsii and gallocatechin on ovine cryopreserved semen viability
(Taylor and Francis, 2025) Liman, Mohammed S.; Hassen, Abubeker; Smuts, Mario P.; Biraima, Ahmed D.A.; Sutovsky, Peter; McGaw, Lyndy Joy; Holm, Dietmar Erik; dietmar.holm@up.ac.za
The objective of this study was to evaluate the effect of a tannin-rich extract from commercial Acacia mearnsii (MTE_0), and gallocatechin, a flavonoid compound derived from Acacia mearnsii, on the long-term viability and motility of cryopreserved ovine semen. Six fresh ejaculates obtained from six adult merino rams twice per week for three weeks were allocated to five aliquots (0, 12.5, 25, 50, and 100 µM gallocatechin added into the Optidyl™ extender) before cooling and cryopreservation. Effects of MTE_0 and gallocatechin on post-thawed motility characteristics were analyzed using computer-assisted semen analysis (CASA), and viability (LIVE/DEAD® kit, Molecular Invitrogen, Waltham, MA), oxidative stress (2,7-dichlorodihydrofluorescein diacetate (H2DCFDA, Thermo Fisher®, Waltham, MA)) for reactive oxygen species (ROS), mitochondrial membrane potential (JC-1 MitoTracker, Molecular Invitrogen, Waltham, MA), acrosomal integrity (lectin PNA), and capacitation using merocyanine 540 (M540) and YO-PRO-1 dyes in flow cytometry. Data were analyzed using one-way ANOVA (IBM SPSS 21.0 for Windows, Armonk, NY). Gallocatechin at 25 µM positively affected (p ≤ .001) kinematic parameters including average path velocity (VAP), progressive velocity (VSL), and beat cross frequency (BCF) of cryopreserved semen. Similarly, gallocatechin at 25 µM- improved sperm motility (live 21.99 ± 2.06%), reduced ROS levels (26.45 ± 1.10%), and mitigated premature capacitation (viable and stable 20.08 ± 1.48%) compared to other treatments. Gallocatechin addition to semen resulted in a significant (p ≤ .001) positive effect compared with the MTE_0 extract. It is concluded that gallocatechin inclusion at 25 µM significantly reduces semen deterioration following cryopreservation. This study is the first to introduce gallocatechin as an efficient antioxidant additive to ovine semen to improve its quality during storage. Our findings will help improve post-thaw ovine semen quality and longevity. Future studies to elucidate the mechanism of anti-oxidative stress action of gallocatechin and its derivatives on semen motility and longevity are recommended.
Thermal properties of rhinoceros ovum pick-up probes : possible effects of temperature shock on oocyte maturation potential
(Medpharm Publications, 2024-11) Vorster, L.; De Bruin, Phillippus Rudolf; Smuts, M.P. (Mario); De la Rey, M.; Herbst, C.; Durrant, B.S.; Holm, Dietmar Erik
BACKGROUND: The implementation of assisted reproductive techniques and use of in vitro embryo production has highlighted their potential in attempts to prevent the extinction of the northern white rhinoceros (Ceratotherium simum cottoni). However, in vitro embryo production has proved challenging. Transrectal ovum pick-up (OPU), while done successfully with custom-made aspiration probes (AP), may expose oocytes to detrimental temperature shock OBJECTIVE: This study compares the temperature regulation properties between two AP, made from different materials and used during OPU in southern white rhinoceros (C. s. simum METHODS: The initial PVC plastic AP, produced using a computer numerical control machine, was compared to a modified aluminium AP. A rhinoceros model was constructed using a 210 L water container fitted with heating elements and a water pump. Water was warmed to 37.5-38.5 °C to simulate rhinoceros body temperature. The AP was equilibrated to room temperature (22 simulating summer) or in a walk-in fridge (4 simulating winter) overnight. Temperature loggers were placed inside and on the outside of the AP RESULTS: The aluminium AP equilibrated to the model water temperature within 15 minutes of submersion in the model, while the temperature of the PVC AP remained significantly lower during the three-hour period. The inside of the PVC AP remained significantly colder compared to outside during both winter and summer (33.23 ± 4.28°C vs. 36.51 ± 2.13 °C and 36.04 ± 1.69 °C vs. 37.22 ± 0.92 °C, respectively). There was no significant difference between the inside temperature of the aluminium AP compared to the outside temperature during both the winter and summer simulations (36.75 ± 0.49 °C vs. 37.83 ± 0.40 °C and 37.86 ± 0.16 °C vs. 38.04 ± 0.11 °C, respectively CONCLUSION: This research highlights the importance of using material with good thermal properties during assisted reproductive procedures. It also contributes to further advancement during the establishment of a successful in vitro embryo production protocol for rhinoceros in South Africa
A review of risk factors at the human-animal-environmental interface of garbage dumps that are driving current and emerging zoonotic diseases
(Elsevier, 2024-12) Sangkachai, Nareerat; Gummow, Bruce; Hayakijkosol, Orachun; Suwanpakdee, Sarin; Wiratsudakul, Anuwat
An increasing trend in zoonotic and emerging infectious diseases (EIDs) has been observed worldwide. Most EID outbreaks originate from wildlife, and these outbreaks often involve pathogen–host–environment interaction. Garbage dumps act as an interface between humans, animals, and the environment, from which EIDs could arise. Therefore, this review considers the presence of important pathogens associated with animals and vectors at garbage dumps from a One Health perspective, looking at animal, human, and environmental factors that play a role. A narrative review was performed focusing on four key points, including garbage dumps, animals, waste pickers, zoonoses and EIDs. Articles addressing the presence of terrestrial animals, insects in garbage dumps, and infectious diseases among waste pickers were included in this study. There were 345 relevant articles covering 395 species of terrestrial animals and insects, consisting of 4 species of amphibians, 180 species of birds, 84 species of insects, 114 species of mammals, and 13 species of reptiles. Furthermore, 97 articles (28.12 %) addressed pathogens found in those populations. About half of the articles were interested in bacterial diseases (52.58 %), followed by parasitic diseases (30.93 %) and viral diseases (30.93 %). Zoonotic pathogens were described in 53.6 % of all articles, while 19.59 % focused on drug-resistant microbes, 13.40 % on rodent-borne diseases, and 7.21 % on vector-borne diseases. Garbage dumps would play a role in the emergence of diseases. The relevant factors at garbage dumps that may increase the risk of disease emergence include increased animal populations and density, increased vector population, newly evolved strains of pathogens, increased interaction between humans, domestic animals, wildlife, and vectors, and socio-economic factors. Therefore, sustainable waste management will reduce waste generation, and improve waste collection, and disposal which helps reduce the emergence of new diseases
A knowledge, attitude and practices assessment of control measures for bovine tuberculosis and brucellosis towards a more effective approach to national control programs in South Africa
(Springer, 2025-01) Kgasi, Alfred T.; Michel, Anita Luise; alfred.kgasi@up.ac.za
Bovine brucellosis and bovine tuberculosis are zoonotic diseases with economic and public health importance across the world, especially in developing countries where the diseases are endemic. The diseases are classified as neglected diseases in developing nations with poor resources despite good control measures in some developed countries. The purpose of this study is to assess the knowledge, attitudes and perceptions (KAP) of stakeholders towards control measures for bovine brucellosis (BR) and bovine tuberculosis (bTB) at a livestock-wildlife interface. Stakeholders selected were small-scale farmers and veterinary officials affected by disease control measures in northern KwaZulu Natal in South Africa. A mixed method approach was used (qualitative and quantitative) In the quantitative method, a total of 61 small-scale livestock farmers and 15 veterinary officials working in the livestock-wildlife interface study area, completed a structured questionnaire. In the qualitative method, a focus group discussion was held with each stakeholder group (farmers and veterinary officials) were held using an interview guide that was developed based on common themes/topics emerging from the quantitative method. In terms of farmers, 62.3% and 75.4%, did not know about BR and bTB, respectively. All veterinary officials (100%) knew about BR and bTB. Majority of small-scale farmers (55.7%) and veterinary officials (66.6%) did not believe that the current methods for control of BR and bTB were effective. However, both farmers (55.9%) and veterinary officials (73.3%) believe that the state has capacity to control the diseases provided adequate resources are available, and practical disease control policies are implemented. Farmers (96.5%) and veterinary officials (93.3%) believe that the success of control of BR and/or bTB also depends on both role players working together. In the focus group discussions, reasons provided were, lack of sufficient resources (people and funding) by the government. Communal farming infrastructure was stated as a hindrance to effective disease control. Poor training of farmers and unrestricted animal movement had negative effect on disease control. Factors such as difficulty in isolating/separating test positive from test negative animals (biosecurity) in communal areas, provincialisation of disease control strategies, lack of enforcement, lack of compensation for farmers, were raised by stakeholders. It is recommended that the current structure of the South African veterinary services’ delivery model be revised to enable coherent disease control co-ordination between National Department and Provinces. The current failures to successful control of BR and bTB can be attributed to limited stakeholder engagement and analysis of stakeholder perspectives. To address this, a bottom-up approach that involves inputs from stakeholders on the ground can help enhance the successful implementation of control strategies. The outcome of the study should serve as guide for policy development and implementation for both BR and bTB control measures in South Africa.
Protective efficacy of a bivalent equine influenza H3N8 virus-like particle vaccine in horses
(Elsevier, 2025-03) O'Kennedy, Martha Magaretha; Reedy, Stephanie E.; Abolnik, Celia; Khan, Amjad; Smith, Tanja; Du Preez, Ilse; Olajide, Edward; Daly, Janet; Cullinane, Ann; Chambers, Thomas M.
Equine influenza (EI) is a highly contagious acute respiratory disease of wild and domesticated horses, donkeys, mules, and other Equidae. EI is caused by the Equine Influenza virus (EIV), is endemic in many countries and outbreaks still have a severe impact on the equine industry globally. Conventional EI vaccines are widely used, but a need exists for a platform that facilitates prompt manufacturing of a highly immunogenic, antigenically matched, updated vaccine product. Here we developed a plant-produced bivalent EI virus-like particle (VLP) vaccine candidate which lacks the viral genome and are therefore non-infectious. We conducted a pilot safety/dose response study of a plant produced bivalent VLP vaccine expressing the HA proteins of Florida clade (FC) 1 and FC2 EIV in 1:1 ratio. Groups of three EIV seronegative horses were vaccinated using four antigen levels (0 sham control, 250, 500, 1000 HAU/dose component). Two doses of vaccines were administered one month apart, and horses were observed for adverse reactions, which were minimal. Sera were collected for hemagglutination inhibition (HI) testing using FC1 and FC2 viruses. One month after the second dose, all horses were challenged with the aerosolized FC1 virus. Horses were observed daily for clinical signs, and nasopharyngeal swabs were collected to quantify viral RNA using qPCR and infectious virus by titration in embryonated hens' eggs. Results showed that all vaccinated groups seroconverted prior to challenge. Post-challenge, both clinical scores and virus shedding were much reduced in all vaccinates compared to the sham-vaccinated controls. We conclude that the VLP vaccines were safe and effective in this natural host challenge model. A safe, efficacious, new-generation bivalent EI VLP vaccine produced in plants, which can promptly and regularly be antigenically matched to ensure optimal protection, will pave the way to highly competitive commercially viable vaccine products for all economic environments globally.
Seroprevalence of Neospora caninum in dairy goats from northern South Africa : a preliminary study
(Elsevier, 2025-02) Tagwireyi, Whatmore Munetsi; Garcia, Gema Alvarez; Morar-Leather, D.; Neves, L.C.B.G.D. (Luís); Thompson, P.N. (Peter N.)
Neospora caninum is an intracellular protozoan parasite with a global distribution, known to cause abortions in livestock. This study aimed to determine N. caninum seroprevalence in dairy goats with a history of reproductive failure in South Africa. Blood samples were collected from 131 dairy goats across five farms in three provinces and tested for N. caninum antibodies using the commercial indirect ELISA (IDvet Screen® Neospora caninum), followed with confirmatory testing with western blot (WB). The ELISA detected antibodies in one goat (1/131) [95 % CI: 0–2.8 %], while no positives were detected by WB. While N. caninum infection and associated abortions do not currently pose a major concern, farmers are encouraged to perform surveillance for potential infections.
Detection of pathogenic serogroups and virulence genes in Listeria monocytogenes strains isolated from beef and beef products retailed in Gauteng Province, South Africa, using phenotypic and polymerase chain reaction (PCR)-based methods
(Wiley-Hindawi, 2024-03-13) Gana, James; Gcebe, Nomakorinte; Moerane, Rebone; Ngoshe, Yusuf Bitrus; Moabelo, Khomotso C.; Adesiyun, Abiodun Adewale; abiodun.adesiyun@up.ac.za
South Africa recently (2017-18) experienced the largest outbreak of human listeriosis in the world caused by L. monocytogenes following the consumption of “polony,” a ready-to-eat meat product. Most (59%) cases originated from Gauteng province, South Africa. As a follow-up study to the outbreak, we used standard bacteriological and molecular methods to determine the prevalence of pathogenic and virulent serogroups of L. monocytogenes in various beef and beef products retailed in Gauteng province, South Africa. The overall prevalence of Listeria spp. was 28% (112/400), comprising Listeria monocytogenes (9.3%), Listeria innocua (16.3%), and Listeria welshimeri (2.5%) (p < 0.001). It is crucial to have detected that the region (p = 0.036), type of product (p = 0.032), and temperature at storage (p = 0.011) significantly affected the occurrence of L. monocytogenes in beef products. It is alarming that pathogenic serogroups 4b-4d-4e (51.4%) and 1/2a-3a (43.2%) were detected among the isolates of L. monocytogenes. Importantly, they were all carriers of seven virulence-associated genes (hlyA, inlB, plcA, iap, inlA, inlC, and inlJ). Our study also demonstrated that 16.7% of “polony” samples investigated were contaminated with L. monocytogenes. Considering that pathogenic and virulent L. monocytogenes contaminated beef and beef products retailed in South Africa, the food safety risk posed to consumers remains and cannot be ignored. Therefore, it is imperative to reduce the contamination of these products with L. monocytogenes during beef production, processing, and retailing to avoid future outbreaks of human listeriosis in the country.
Absence of tuberculosis-causing Mycobacteria from slaughtered livestock tissues and environmental samples, Gauteng Province, South Africa
(Wiley-Hindawi, 2024-03-15) Mareledwane, Vuyokazi Epipodia; Adesiyun, Abiodun Adewale; Hlokwe, Tiny M.
Mycobacterium tuberculosis complex (MTBC) is a group of bacteria responsible for causing tuberculosis in animals and humans. In South Africa (S.A), slaughterhouses are registered by the government and closely inspected and audited for hygienic slaughter practices. Meat inspection to detect lesions has been used for passive surveillance, monitoring, and diagnosis of the disease status. Information on the current status of bovine tuberculosis (bTB) in livestock in the country is limited. Hence, we investigated the occurrence of Mycobacterium spp. in the tissues of slaughtered livestock and environmental samples in abattoirs in Gauteng province of South Africa (S.A). +e cross-sectional study employing random sampling from cattle, pigs, and sheep (with the collection of liver, lung, spleen, and di7erent lymph nodes) irrespective of lesions was carried out in 19 red meat abattoirs. Five hundred animals were sampled, comprising cattle (n 369), pigs (n 90), and sheep (n 41). Additionally, 19 environmental samples were collected from feedlots, or where animals drink water while awaiting slaughter, to identify mycobacterial species using culture, acid-fast bacteria staining, and polymerase chain reaction (PCR). +e Chi-square and Fisher’s Exact tests were used to detect statistically signi=cant di7erences in the frequency of detection of Mycobacterium spp. according to the variables investigated (types of tissues, livestock, abattoirs, etc.). +e PCR assays detected no MTBC complex species DNA in the bacterial isolates from cattle (n 32). Sequence analysis (16S rDNA) of the isolates from eight cattle con=rmed only two species, namely Mycobacterium colombiense (99.81% identity) and Mycobacterium simiae (99.42% identity). +eremaining isolates were identi=ed as members of the Actinomadura species. From the environmental samples, bacterial isolation was made from three samples, and two could only be identi=ed up to the genus level (Mycobacterium species) while the remaining isolate was identi=ed as Mycobacterium senuense (99.22% identity). +e study revealed the absence of bovine tuberculosis-causing pathogens in red meat abattoirs of the Gauteng province. Although non-tuberculous Mycobacteria have been implicated as potentially causing tuberculosis-like diseases in livestock, their occurrence in the current study was found to be low, but the potential to cause disease cannot be ignored.
Whole genome sequence analysis of Listeria monocytogenes isolates obtained from the beef production chain in Gauteng Province, South Africa
(MDPI, 2024-05-16) Gana, James; Gcebe, Nomakorinte; Pierneef, Rian Ewald; Chen, Yi-Liang; Moerane, Rebone; Adesiyun, Abiodun Adewale; abiodun.adesiyun@up.ac.za
The study used whole-genome sequencing (WGS) and bioinformatics analysis for the genomic characterization of 60 isolates of Listeria monocytogenes obtained from the beef production chain (cattle farms, abattoirs, and retail outlets) in Gauteng province, South Africa. The sequence types (STs), clonal complexes (CCs), and the lineages of the isolates were determined using in silico multilocus sequence typing (MLST). We used BLAST-based analyses to identify virulence and antimicrobial genes, plasmids, proviruses/prophages, and the CRISPR-Cas system. The study investigated any association of the detected genes to the origin in the beef production chain of the L. monocytogenes isolates. Overall, in 60 isolates of Listeria monocytogenes, there were seven STs, six CCs, forty-four putative virulence factors, two resistance genes, one plasmid with AMR genes, and three with conjugative genes, one CRISPR gene, and all 60 isolates were positive for proviruses/prophages. Among the seven STs detected, ST204 (46.7%) and ST2 (21.7%) were the most prominent, with ST frequency varying significantly (p < 0.001). The predominant CC detected were CC2 (21.7%) and CC204 (46.7%) in lineages I and II, respectively. Of the 44 virulence factors detected, 26 (across Listeria Pathogenicity Islands, LIPIs) were present in all the isolates. The difference in the detection frequency varied significantly (p < 0.001). The two AMR genes (fosX and vga(G)) detected were present in all 60 (100%) isolates of L. monocytogenes. The only plasmid, NF033156, was present in three (5%) isolates. A CRISPR-Cas system was detected in six (10%), and all the isolates carried proviruses/prophages. The source and sample type significantly affected the frequencies of STs and virulence factors in the isolates of L. monocytogenes. The presence of fosX and vga(G) genes in all L. monocytogenes isolates obtained from the three industries of the beef production chain can potentially cause therapeutic implications. Our study, which characterized L. monocytogenes recovered from the three levels in the beef production chain, is the first time genomics was performed on this type of data set in the country, and this provides insights into the health implications of Listeria.
Virulence potential and antimicrobial resistance of Listeria monocytogenes isolates obtained from beef and beef-based products deciphered using whole-genome sequencing
(MDPI, 2024-06-08) Manqele, Ayanda; Adesiyun, Abiodun Adewale; Mafuna, Thendo; Pierneef, Rian Ewald; Moerane, Rebone; Gcebe, Nomakorinte
Listeria monocytogenes is a ubiquitous bacterial pathogen that threatens the food chain and human health. In this study, whole-genome sequencing (WGS) was used for the genomic characterization of L. monocytogenes (n = 24) from beef and beef-based products. Multilocus Sequence Type (MLST) analysis revealed that ST204 of CC204 was the most common sequence type (ST). Other sequence types detected included ST1 and ST876 of CC1, ST5 of CC5, ST9 of CC9, ST88 of CC88, ST2 and ST1430 of CC2, and ST321 of CC321. Genes encoding for virulence factors included complete LIPI-1 (pfrA-hly-plcA-plcB-mpl-actA) from 54% (13/24) of the isolates of ST204, ST321, ST1430, and ST9 and internalin genes inlABC that were present in all the STs. All the L. monocytogenes STs carried four intrinsic/natural resistance genes, fosX, lin, norB, and mprF, conferring resistance to fosfomycin, lincosamide, quinolones, and cationic peptides, respectively. Plasmids pLGUG1 and J1776 were the most detected (54% each), followed by pLI100 (13%) and pLM5578 (7%). The prophage profile, vB_LmoS_188, was overrepresented amongst the isolates, followed by LP_101, LmoS_293_028989, LP_030_2_021539, A006, and LP_HM00113468. Listeria genomic island 2 (LGI-2) was found to be present in all the isolates, while Listeria genomic island 3 (LGI-3) was present in a subset of isolates (25%). The type VII secretion system was found in 42% of the isolates, and sortase A was present in all L. monocytogenes genomes. Mobile genetic elements and genomic islands did not harbor any virulence, resistance, or environmental adaptation genes that may benefit L. monocytogenes. All the STs did not carry genes that confer resistance to first-line antibiotics used for the treatment of listeriosis. The characterization of L. monocytogenes in our study highlighted the environmental resistance and virulence potential of L. monocytogenes and the risk posed to the public, as this bacterium is frequently found in food and food processing environments.
Calcium and magnesium abnormalities in puppies with parvoviral enteritis
(American Veterinary Medical Association, 2025-01) Mouton, Anneri; Celliers, Anri; Thompson, P.N. (Peter N.); Mellanby, Richard J.; Schoeman, Johan P.; anneri.mouton@up.ac.za
OBJECTIVE : To determine the association between ionized calcium (iCa) and/or total magnesium (tMg) and the development of sepsis and to investigate whether iCa or tMg is associated with mortality in puppies with canine parvoviral enteritis (CPE). METHODS : 64 client-owned puppies with CPE were enrolled in this prospective cohort study. Serum iCa and tMg were measured daily from admission until death or discharge. Fifteen healthy client-owned puppies were used as controls. RESULTS : Mean iCa concentrations of the CPE group on admission were significantly lower compared to the control group (1.35 mmol/L vs 1.52 mmol/L). Ionized calcium concentrations of nonsurvivors were significantly higher compared to survivors on day 2 but not on any other days. Puppies that were hypercalcemic on day 2 were also significantly more likely to die than normocalcemic puppies (OR, 10.7; 95% CI, 1.7 to 71). Ionized calcium was not associated with the development of sepsis on any day. In contrast, mean admission tMg concentrations of the CPE group were significantly higher compared to the control group (0.72 mmol/L vs 0.63 mmol/L). However, tMg concentrations were not significantly different between survivors and nonsurvivors nor were they associated with the development of sepsis on any day. CONCLUSIONS : On admission, puppies with CPE had lower iCa and higher tMg compared to healthy puppies, and higher iCa a day after initiation of treatment was associated with increased odds of mortality. CLINICAL RELEVANCE : The results of this study provide insight into calcium homeostasis in critically ill young dogs with CPE.
Ketamine-butorphanol-medetomidine for the immobilisation of free-living hyenas (Crocuta crocuta)
(Medpharm Publications, 2024-03) Roug, Annette; Meyer, Leith Carl Rodney; Netshitavhadulu, L.; Leiberich, Marion; Buss, Peter
Free-ranging spotted hyenas (Crocuta crocuta) are immobilised for a variety of purposes, including wildlife-human conflict mitigation, research, and veterinary treatment. Combinations of tiletamine-zolazepam (Zoletil) and medetomidine are commonly used for immobilisation of hyenas, however, recovery times are long. In this descriptive study, a total of 20 adult or subadult free-ranging hyenas were immobilised near Skukuza in the Kruger National Park using ketamine, butorphanol, and medetomidine. The goal of the study was to evaluate a suitable dose and measure cardiorespiratory effects of this combination. The quality of induction and recovery were scored using an established scoring system from 1 (excellent) to (poor). Twelve of the 20 hyenas were given an induction score of 1 (excellent), five an induction score of 2 (good), and three an induction score of 3 (fair). Of the animals with induction score = 1, the mean drug dose was 1.17 mg/kg ketamine, 0.25 mg/kg butorphanol and 0.03 mg/kg medetomidine, and the mean induction time and time to handling 6:25 minutes and 9:46 minutes respectively. The mean recovery time (from reversal to standing) was 10:16 min, which is shorter than what has been reported for tiletaminezolazepam- based combinations in hyenas. Most hyenas were bradycardic (< 40 beats per minute) and the mean PaO2 69.5 mmHg. Three hyenas, one with induction score = 2, and two with induction scores = 3 spontaneously recovered at 33, 44 and 56 minutes post approach respectively. Regardless of induction time, all hyenas reached a level of surgical anaesthesia while immobilised. Overall, ketamine-butorphanol-medetomidine (KBM) was effective in immobilising hyenas but induction times varied, and animals were bradycardic during immobilisation.
The effect of a warmed enema during ovum pick-up on subsequent in vitro oocyte maturation in southern white rhinoceros (Ceratotherium simum simum)
(Medpharm Publications, 2024-08) Vorster, L.; De Bruin, Phillippus Rudolf; Smuts, M.P. (Mario); Durrant, B.S.; De la Rey, M.; Herbst, C.; Holm, Dietmar Erik
BACKGROUND : Rhinoceros are currently one of the most threatened mammal species globally. Slow population growth, increased poaching and habitat destruction have led to increased conservation efforts for each species. Assisted reproductive technologies (ART) have been implemented in an attempt to aid reproductive outputs for the conservation of these endangered species. Developing species-specific ART programmes for wildlife have been challenging. Temperature control during oocyte recovery is essential for ensuring in vitro success. OBJECTIVE : This study is the first to investigate the effect of enema warming prior to trans-rectal ovum pick-up (OPU) on in vitro oocyte maturation in Southern white rhinoceros (Ceratotherium simum simum). METHODS : OPUs were performed on 20 rhinoceros cows from three different game farms in South Africa; oocytes were transported to one of two in vitro fertilisation laboratories for culture. The enema fluid was either warmed to 32 °C or not warmed prior to the OPU. Location of the farm, the different laboratories, ambient temperature, season, aspiration probe temperature, media type and enema temperature were investigated as predictor variables for oocyte maturation success. RESULTS : After considering all other potential covariates, warming of the enema fluid was the only independent predictor of in vitro oocyte maturation success during this study. CONCLUSION : Oocytes retrieved from rhinoceros cows that received an enema warmed to 32 °C were 2.3 times more likely to mature in vitro compared to oocytes from cows that received an unwarmed enema; the findings can be implemented in other rhinoceros ART programmes and in conservation efforts of other endangered mammalian species.
The time course of lactate and endocrine changes in dogs suffering from dog bite wounds
(Medpharm Publications, 2024-03) Van Zyl, Este; Thompson, P.N. (Peter N.); Schoeman, Johan P.
BACLGROUND : The stress response after acute trauma in humans and animals has been well-recognised in the literature. However, data on temporal changes in endocrine parameters after acute trauma in previously healthy dogs are scant. OBJECTIVE : To longitudinally track endocrine variables and lactate concentrations in dogs with canine bite wounds. METHOD : Prospective study involving 20 dogs hospitalised after being bitten by another dog. Serum cortisol, thyroxine (total T4), thyrotropin (TSH), and lactate concentrations were measured on admission and every 8 hours after the recorded bite incident, for a 72-hour period. RESULTS : Median cortisol concentration was markedly elevated on admission (314.6 nmol/L; IQR 229.3–369.6) but returned to within the reference interval by 16 hours post-bite (99.5 nmol/L; IQR 48.7–225.4) and reached a nadir at 48 hours post-bite (38.5 nmol/L; IQR 32.1–115.9). Median total T4 concentration was within the reference interval on admission (20.6 nmol/L; IQR 12.7–27.9) but decreased below the reference interval by 8 hours (11.0 nmol/L; IQR 5.0–14.1) and reached a nadir 16 hours postbite (7.0 nmol/L; IQR 2.9–19.7), before gradually increasing after 64 hours to reach the reference range by 72 hours. The median TSH concentrations remained within the reference interval throughout the study period. Median lactate concentration was mildly elevated on admission (3.0 mmol/L; IQR 2.0–3.9). CONCLUSION : This study produced novel data on the temporal relationships of the hypothalamic-pituitary-adrenal and hypothalamicpituitary- thyroidal axes alterations after an acute traumatic insult in dogs.
Comparison of the immobilisation and cardiorespiratory effects of thiafentanil-azaperone versus thiafentanil-medetomidine-azaperone in African buffalo (Syncerus caffer)
(Medpharm Publications, 2024-03) Faber, Vanessa; Burroughs, Richard E.J.; Meyer, Leith Carl Rodney; Hansen, H.J.; Gerber, D.; Koeppel, Katja Natalie
African buffalo (Syncerus caffer) are frequently immobilised for veterinary interventions, disease screening and translocations. Concerns over user and animal safety, costs, and irregularities in opioid supply, have led to the development of alternative immobilisation protocols. This study compared immobilisation of 12 boma-habituated African buffalo with thiafentanil-azaperone (TA) vs. thiafentanil-medetomidine-azaperone (TMA) in a randomised crossover study. Each buffalo received a combination of thiafentanil (6–7 mg) + azaperone (40 mg) and thiafentanil (1 mg) + medetomidine (3–4 mg) + azaperone (40 mg) with a three-week washout period between immobilisations. Induction and recovery times were recorded, quality of induction and immobilisation were scored subjectively, and physiological variables were monitored. The TMA combination induced immobilisation with 1/7th of the TA thiafentanil dose and at a quarter of the cost. Induction times for the TA combination were significantly faster at 5.7 ± 1.6 min and more reliable compared to the TMA combination at 10.95 ± 3.9 min. Both combinations resulted in severe hypoxaemia, however hypoxaemia was overall more pronounced in the TMA (PaO2 44 ± 14 mmHg) combination compared to the TA (PaO2 51 ± 13,33 mmHg) combination and resulted mainly from decreased pulmonary oxygen exchange rather than hypoventilation; PaCO2 values were mostly within the normal expected physiological range. Supplementary oxygen and close monitoring of blood oxygenation is considered essential with either combination. Although the reduction in costs could be beneficial for the wildlife industry, longer induction times, and risks from severe hypoxaemia need to be taken into consideration when the TMA combination is used.

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