Background and Aim: Newcastle disease (ND) is widely recognized as an extremely harmful and contagious disease of birds. Therefore, the present study aims to evaluate the effect of oxidative stress induced by the virulent ND virus (NDV) (KUDU 113) on the plasma, brain, bursa of Fabricius, NDV antibody response, and hematology as well as the ameliorative effect of the individual or combined use of Vitamins E and C on the clinical signs of NDV-infected chickens. Materials and Methods: In this study, a total of 150 broiler chickens were included and divided into five groups: Group 1, nonsupplemented and unchallenged chickens (UCC); Group 2, nonsupplemented and challenged chickens (ICC); Group 3, Vitamin C-supplemented + challenged chickens; Group 4, Vitamin E-supplemented + challenged chickens; and Group 5, Vitamins E and C-supplemented + challenged chickens. Groups 3, 4, and 5 were supplemented with Vitamins E and C (33 and 400 mg/kg/day, respectively). Virus challenge was done with 0.1 ml of KUDU 113 7 days after the start of vitamin inclusion in their diet. Concentrations of glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), and catalase (CAT) were analyzed in the plasma, brain, and bursa on days 0, 3, and 7 post-infection (pi) using the biochemical method. The blood samples were randomly collected from five chickens in each group for antibody response and hematological analyses on day 0 previtamin treatment and at 0, 3, 7, 10, 14, and 21 days pi (dpi). Results: A significant increase in the concentrations of MDA and NO in the NDV-challenged chickens was observed when compared with the UCCs. Moreover, a significant decrease in GSH concentration was observed in the NDV-challenged chickens when compared with the UCCs. The activities of CAT and SOD were reduced markedly in the NDV-challenged chickens. Increases in the mean antibody titers were observed in the NDV-challenged group when compared with the UCCs from days 3 to 21 pi. The mortality rates of groups 1, 2, 3, 4, and 5 were 0%, 30%, 3.3%, 3.3%, and 26.6%, respectively. Conclusion: The findings of this study suggest that KUDU 113 causes oxidative stress in the brain and bursa of Fabricius of chickens. Individual supplementation with Vitamin E or C was found to be more effective in ameliorating oxidative stress, improving the immune response, and reducing mortality in KUDU 113 infections than the combined supplementation of Vitamins C and E.

Background: Staphylococcus aureus is a major zoonotic and foodborne pathogen with substantial One Health implications, yet its prevalence, resistance, and virulence potential within the aquaculture sector in Nigeria remains poorly characterized. Objectives: To supplement existing information, this current study investigated the prevalence, clonal distribution, antimicrobial resistance, and virulence gene profiles of S. aureus isolates from fish, fish water, and occupationally exposed fish handlers in Anambra State, Southeast Nigeria. Methods: A total of 607 samples—comprising 465 surface swabs from raw and processed fish, 36 fish water samples, and 106 nasal swabs from fish handlers—were processed using selective culture, biochemical tests, antimicrobial susceptibility testing, DNA microarray analysis, spa typing, and SCCmec typing. Results: S. aureus was recovered from 16.5% (100/607) of the samples. Fourteen (14%) isolates were methicillin-resistant (MRSA), harboring mecA and SCCmec types IV and V, with a combined MRSA prevalence of 2.3%. Multidrug resistance was observed in 52.2% of isolates (mean Multiple Antimicrobial Resistance index: 0.23), with 19 resistance genes spanning nine antimicrobial classes—including heavy metal and biocide resistance. Twenty-eight spa types across 13 clonal complexes (CCs) were identified, with CC1, CC5, and CC8 predominating. The detection of shared spa types between fish and handlers indicates potential cross-contamination. Detected virulence genes included those for accessory gene regulators (agrI-IV), Pantone–Valentine leucocidin (lukFS-PV), toxic shock syndrome (tsst-1), hemolysins (hla, hlb, hld/hlIII, hlgA), biofilm formation (icaA, icaD), immune evasion (chp, scn, sak), enterotoxins (sea, seb, sec, sed, egc, and others), exfoliative toxins (etA, etB), epidermal cells differentiation (edinA, edinB), and capsular types (cap5, cap8). Conclusions: This study reveals that the aquaculture sector in Southeast Nigeria serves as a significant reservoir of genetically diverse, multidrug-resistant S. aureus strains with robust virulence profiles. These findings highlight the necessity of integrated One Health surveillance and targeted interventions addressing antimicrobial use and hygiene practices within aquatic food systems.

Background: Animal-associated antimicrobial-resistant staphylococci pose a One Health concern, as they can spread into the environment and cause serious infections. Yet, donkeys in Nigeria have been largely overlooked as potential reservoirs of these pathogens. Aim/Objectives: To isolate Staphylococcus aureus from donkeys in Obollo-Afor, southeast Nigeria, assess their antimicrobial resistance profiles, and evaluate their virulence potential. Materials and Methods: Staphylococci were isolated from the nasal swabs of 250 donkeys, using mannitol salt agar, confirmed biochemically, with Staphylococcus aureus identified via a latex agglutination test and mass spectrometry. The resistance profiles of the isolates, including in regard to methicillin, inducible clindamycin, and β-lactamase production, were determined using disc diffusion, while vancomycin resistance was assessed through the use of agar dilution. The virulence factors were evaluated phenotypically. Results: Of the 250 samples, 11 (4.4%) contained S. aureus and 239 (95.6%) grew other Staphylococcus species. The resistance rates of the 11 S. aureus isolates to gentamicin, penicillin, tigecycline, cefoxitin, linezolid, and chloramphenicol were 45.5%, 66.7%, 54.5%, 27.3%, 36.4%, and 18.1%, respectively. The phenotypic methicillin-resistant S. aureus prevalence was 1.2%. Additionally, 23.5% of the S. aureus isolates were multidrug resistant, with a mean antibiotic resistance index of 0.25. All the S. aureus isolates exhibited virulence factors like clumping factor expression, catalase, caseinase, lecithinase, and gelatinase activity, while the occurrence of haemagglutinin, biofilm, pellicle, and hemolysin occurred in 27.3%, 54.5%, 36.4%, 72.2%, respectively. Conclusion: Although a small percentage of donkeys in Nigeria may harbor S. aureus, these animals are potentially spreading antimicrobial resistance, including multidrug and methicillin resistance, to humans and the environment.

Background: Frequent use of colistin (COL) and tetracyclines in the Nigerian poultry sector potentially triggers bacterial resistance against COL and tigecycline (TIG), which are last-line antibiotics used to treat multidrug-resistant infections. Aim/Objectives: This study aimed to isolate COL- and TIG-resistant E. coli from commercial day-old chicks distributed to poultry farmers in Nsukka Southeastern Nigeria, assess the production of extended-spectrum β-lactamase (ESBL) and carbapenemase by the isolates, and establish their pathogenic potentials. Materials and Methods: Non-duplicate cloacal swabs were systematically collected from 250 randomly selected day-old chicks. MacConkey agar with 1 µg/mL of COL and 16 µg/mL of tetracycline was used for the isolation of putative COL- and tetracycline-resistant E. coli, respectively. E. coli isolates were confirmed biochemically using the API20E Gram-negative identification kit and molecularly by polymerase chain reaction targeting the uidA gene. Phenotypic COL resistance was established using COL agar and COL disc elution tests, while TIG insusceptibility was determined with disc diffusion. ESBL and carbapenemase production was assessed by double-disc synergy and modified carbapenem inactivation methods, respectively. Pathogenic potentials were determined using phenotypic methods. Results: COL- and TIG-resistant E. coli was recovered from 95 (38.0%) and 62 (24.8%) swabs from the 250 chicks, respectively. None of the isolates were potential ESBL or carbapenemase producers. The COL-resistant isolates displayed pathogenic potentials such as biofilm formation, haemagglutination, cell surface hydrophobicity, surface layer, and gelatinase activities at rates of 30.7%, 8.4%, 33.7%, 23.5%, and 17.6%, respectively. Meanwhile, the TIG-resistant isolates exhibited their respective potentials at rates of 47.0%, 21.0%, 35.5%, 58.1%, and 43.6%. Red, dry, and rough (RDAR) was the predominant curli fimbriae, and the cellulose morphotype portrayed by both the COL- and TIG-unsusceptible potential biofilm-producing isolates. Conclusions: This study demonstrates that a significant percentage of commercial day-old chicks distributed to farmers in Nsukka, southeastern Nigeria, are colonized by potentially pathogenic COL- and TIG-resistant E. coli, which could spread to humans and the environment.

Non-typhoidal Salmonella (NTS) is an important poultry-associated pathogen with major One Health and economic impacts, but data on its epidemiology and antimicrobial resistance in Nigeria remain limited. This study investigated the prevalence, serovar distribution, clonal relatedness, and antimicrobial resistance of NTS along the poultry production chain in Enugu State, southeastern Nigeria. A total of 2400 samples were collected, comprising feces (cecal content)/cloacal swabs from chickens (n = 1100), eggs (n = 400), chicken meat (n = 600), and stool samples from poultry workers (n = 300). Isolation and identification were performed using standard bacteriological methods, with confirmation by serotyping and polymerase chain reaction (PCR) targeting the invA gene. Genetic relatedness was assessed using enterobacterial repetitive intergenic consensus (ERIC)-PCR, and antimicrobial susceptibility was determined by the disk diffusion method. Overall, 47 (2.0%) Salmonella enterica isolates were recovered from 2400 samples, with the highest prevalence observed in eggs (3.5%), followed by human stool (3.3%), chicken meat (1.8%), and chicken feces (1.1%). Only 35 (11.8%) of the 297 sampled farms were positive for Salmonella, and recovery rates differed significantly (p = 0.0065) among sample sources. Five serotypes were identified, dominated by S. Typhimurium (57.4%), followed by S. Enteritidis (14.9%), S. Anatum (12.8%), S. Stanley (8.5%), and S. Agona (6.3%). ERIC-PCR revealed multiple clonal clusters, many containing isolates from mixed sources, indicating circulation of related strains between poultry and humans. All isolates were resistant to ampicillin, with high resistance to tetracycline (76.6%), sulphamethoxazole–trimethoprim (51.1%), and fluoroquinolones. Overall, 80.9% of isolates were multidrug-resistant, with a mean Multiple Antibiotic Resistance Index of 0.29, highest among isolates from chicken feces. Although the prevalence of NTS was low, the presence of genetically related multidrug-resistant strains across the production chain underscores the role of poultry as a reservoir for zoonotic transmission and highlights the need for coordinated One Health surveillance and antimicrobial stewardship strategies in Nigeria.

Small ruminant productivity in Nigeria has been hampered by the Peste des Petits Ruminants Virus (PPRV) and a subsequent bacterial infection. It is vital to understand the most prevalent bacteria that might exacerbate PPRV disease in order to enhance the prognosis and treatment of PPRV patients. Sheep and goats offered for sale at local markets in Nigeria's Enugu state were examined for typical clinical manifestations of PPR infection and selected for this study. Two hundred and ten ocular, nasal and oral swab samples were collected from 70 sheep and goats. An additional 70 nasal swabs were collected for molecular confirmation by reverse transcriptase polymerase chain reaction, while the remainder were used for bacterial isolation and identification. The detection rate of the PPRV gene was 25.7% (18/70), affecting three sheep (4.3%; 3/70) and 15 goats (21.4%; 15/70). Based on the PPRV-positive animals, 72 bacterial isolates consisting of eight genera and eleven species were obtained. Staphylococcus aureus was the most frequently isolated gram-positive bacterium (31.9%; 23/72), while Escherichia coli was the most frequently isolated gram-negative bacterium (19.44%; 14/72). Staphylococci were the most frequently isolated bacteria from all samples. This study found that small ruminants infected with PPRV were sold in the study area, providing a potential means of spreading the disease to other animals. In addition, it is highlighted that several bacteria, some of which might belong to the normal flora, might complicate and worsen the clinical presentation of PPRV cases.