Gold Nanoparticle-Based Plasmonic Detection of Escherichia coli, Salmonella enterica, Campylobacter jejuni, and Listeria monocytogenes from Bovine Fecal Samples.

Current diagnostic methods for detecting foodborne pathogens are time-consuming, require sophisticated equipment, and have a low specificity and sensitivity. Magnetic nanoparticles (MNPs) and plasmonic/colorimetric biosensors like gold nanoparticles (GNPs) are cost-effective, high-throughput, precise, and rapid. This study aimed to validate the use of MNPs and GNPs for the early detection of Escherichia coli O157:H7, Salmonella enterica spp., Campylobacter jejuni, and Listeria monocytogenes in bovine fecal samples. The capture efficiency (CE) of the MNPs was determined by using Salmonella Typhimurium (ATCC_13311) adjusted at an original concentration of 1.5 × 108 CFU/mL. One (1) mL of this bacterial suspension was spiked into bovine fecal suspension (1 g of fecal sample in 9 mL PBS) and serially diluted ten-fold. DNA was extracted from Salmonella Typhimurium to determine the analytical specificity and sensitivity/LOD of the GNPs. The results showed that the CE of the MNPs ranged from 99% to 100% and could capture as little as 1 CFU/mL. The LOD of the GNPs biosensor was 2.9 µg/µL. The GNPs biosensor was also tested on DNA from 38 naturally obtained bovine fecal samples. Out of the 38 fecal samples tested, 81.6% (31/38) were positive for Salmonella enterica spp., 65.8% (25/38) for C. jejuni, 55.3% (21/38) for L. monocytogenes, and 50% (19/38) for E. coli O157:H7. We have demonstrated that MNP and GNP biosensors can detect pathogens or their DNA at low concentrations. Ensuring food safety throughout the supply chain is paramount, given that these pathogens may be present in cattle feces and contaminate beef during slaughter.

Molecular phylogeny of coronaviruses and host receptors among domestic and close-contact animals reveals subgenome-level conservation, crossover, and divergence.

BACKGROUND: Coronaviruses have the potential to cross species barriers. To learn the molecular intersections among the most common coronaviruses of domestic and close-contact animals, we analyzed representative coronavirus genera infecting mouse, rat, rabbit, dog, cat, cattle, white-tailed deer, swine, ferret, mink, alpaca, Rhinolophus bat, dolphin, whale, chicken, duck and turkey hosts; reference or complete genome sequences were available for most of these coronavirus genera. Protein sequence alignments and phylogenetic trees were built for the spike (S), envelope (E), membrane (M) and nucleocapsid (N) proteins. The host receptors and enzymes aminopeptidase N (APN), angiotensin converting enzyme 2 (ACE2), sialic acid synthase (SAS), transmembrane serine protease 2 (TMPRSS2), dipeptidyl peptidase 4 (DPP4), cathepsin L (and its analogs) and furin were also compared. RESULTS: Overall, the S, E, M, and N proteins segregated according to their viral genera (α, ß, or γ), but the S proteins of alphacoronaviruses lacked conservation of phylogeny. Interestingly, the unique polybasic furin cleavage motif found in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) but not in severe acute respiratory syndrome coronavirus (SARS-CoV) or Middle East respiratory syndrome coronavirus (MERS-CoV) exists in several ß-coronaviruses and a few α- or γ-coronaviruses. Receptors and enzymes retained host species-dependent relationships with one another. Among the hosts, critical ACE2 residues essential for SARS-CoV-2 spike protein binding were most conserved in white-tailed deer and cattle. CONCLUSION: The polybasic furin cleavage motif found in several ß- and other coronaviruses of animals points to the existence of an intermediate host for SARS-CoV-2, and it also offers a counternarrative to the theory of a laboratory-engineered virus. Generally, the S proteins of coronaviruses show crossovers of phylogenies indicative of recombination events. Additionally, the consistency in the segregation of viral proteins of the MERS-like coronavirus (NC_034440.1) from pipistrelle bat supports its classification as a ß-coronavirus. Finally, similarities in host enzymes and receptors did not always explain natural cross-infections. More studies are therefore needed to identify factors that determine the cross-species infectivity of coronaviruses.

Serological evidence of Coxiella burnetii infection in slaughtered sheep and goats at Kumasi Abattoir, Ghana.

Q fever, caused by Coxiella burnetii, is an important zoonosis worldwide. Q fever is documented in many parts of the world; however, information on the disease in Ghana is scanty. This study was therefore conducted to provide evidence of exposure of sheep and goats slaughtered at the Kumasi Abattoir to Coxiella burnetii. A total of 350 serum samples collected from 175 sheep and 175 goats were analyzed for the presence of C. burnetii antibodies using a commercial ELISA kit (ID Vet). Results of the study established a seroprevalence of 28.57% in goats, 16.57% in sheep and an overall seroprevalence of 22.29% in sheep and goats; 20.57% for male sheep, 23.86% for female sheep, 26.44% for male goats and 30.68% for female goats. Results showed that goats are more at risk to the infection than sheep however sex is not a risk factor. This study confirms the existence of Q fever in sheep and goats in Ghana hence, the disease should be considered as a public health risk to workers at the abattoir and other stakeholders in the sheep and goat production chain.

Seroprevalence of Toxoplasma Gondii antibodies in sheep and goats slaughtered at the Kumasi Abattoir, Ghana.

Toxoplasmosis, caused by T. gondii, is an important zoonosis worldwide. In Ghana, information on the disease in humans abounds but scanty in animals. This study was therefore conducted to estimate the seroprevalence of T. gondii infection sheep and goats sampled from the Kumasi Abattoir in Ashanti Region, Ghana. A total of 347 serum samples collected from 170 sheep and 177 goats were analyzed for the presence of T. gondii antibodies using a commercial ELISA kit. Results of this study estimated the seroprevalence of 23.7% in goats an, 35.9% in sheep. In sheep, 24 (35.82%) out of a total of 67 male samples were positive and 37 (35.92%) out of a total of 104 female samples were positive while in goats, 6 (8.2%) bucks out of a total of 73 were positive while 36 (34.6%) does out of a total of 104 were positive. There was a significant difference in the rate of seropositivity of female goats (p-value 0.01). This study confirms the existence of T. gondii infection in small ruminants in Ghana and it showed that sheep and dogs are more at risk to T. gondii infection hence meat from such animals could be a potential risk to public health if consumed raw or undercooked.