Antimicrobial use, residue and resistance dissemination in freshwater fish farms of north-central Nigeria: One health implications

Tetracycline and sulphonamide residues in farmed fish in Dar es Salaam, Tanzania and human health risk implications

In Africa, antibiotic residue investigations in animal food have primarily been focused on meat, neglecting farmed fish. This cross-sectional study conducted in Dar es Salaam, Tanzania, aimed to assess sulphonamide and tetracycline residues in farmed fish, comparing levels with Codex Alimentarius Commission's acceptable daily intake (ADI) and maximum residue limits (MRLs). A total of 84 farmed fish were sampled and analysed in the presence of tetracycline and sulphonamide residues. All samples were positive for sulphonamide residues (100%; n = 84), and 2.4% (n = 2) were positive for tetracycline and consequently also positive for both compounds. Tetracycline levels were below ADI and MRL, 28.5% (n = 24) surpassed the ADI, and 6% (n = 5) of the samples exceeded the MRL for sulphonamide. Regular monitoring of antibiotic residues in aquaculture products is crucial to mitigate health risks and expanding assessments to include other commonly used compounds is warranted.

Antimicrobial use and resistance in food animal production: food safety and associated concerns in Sub-Saharan Africa

The use of antimicrobials in food animal (FA) production is a common practice all over the world, with even greater usage and dependence in the developing world, including Sub-Saharan Africa (SSA). However, this practice which serves obvious economic benefits to producers has raised public health concerns over the last decades, thus driving the selection and dissemination of antimicrobial resistance and adversely impacting food safety and environmental health. This review presents the current and comprehensive antimicrobial usage practices in food animal production across SSA. We further highlighted the overall regional drivers as well as the public health, environmental, and economic impact of antimicrobial use in the production of food animals. Antimicrobial use is likely to increase with even exacerbated outcomes unless cost-effective, safe, and sustainable alternatives to antibiotics, especially probiotics, prebiotics, bacteriocins, antimicrobial peptides, bacteriophages, vaccines, etc. are urgently advocated for and used in food animal production in SSA. These, in addition to the implementation of strong legislation on antimicrobial use, and improved hygiene will help mitigate the public health concerns associated with antimicrobial use in food animals and improve the well-being and safety of food animals and their products.

Antimicrobial usage and associated residues and resistance emergence in smallholder beef cattle production systems in Nigeria: A One Health challenge

Livestock intensification has facilitated antimicrobial use (AMU) with consequent antimicrobial resistance (AMR) development. We assessed AMU in beef farms, pathways for residues and resistance dissemination to humans, risk status, residues identification, and drivers for antimicrobial residues and resistance emergence in beef cattle production systems. A cross-sectional survey was conducted in randomly selected beef farms of Northern Nigeria, between 2018 and 2019. Traffic Light model and Disc Diffusion Test were used to assess risk status and determined residues, respectively. Data was analyzed using descriptive statistics and logistic regression models at 95% confidence level. About 92% (n = 608) farmers participated. The majority of farmers managing intensive (78.9%) and semi-intensive (76.6%) farms did not follow antimicrobial dosage instructions. Also, 72.4% and 83.9% of the farmers on intensive and semi-intensive systems, respectively, did not observed withdrawal periods after AMU. Furthermore, 71.5% farmers in intensive and 53.2% in semi-intensive farms used antimicrobials as growth promoters. Antimicrobials frequently used include tetracyclines, sulfonamides and penicillin. Antimicrobial residues and resistance dissemination pathways from beef herds were: consumption of contaminated meat with residues (p = 0.007); contacts with contaminated cattle and fomites (p < 0.001); and contaminated manure and aerosols in farm environment (p = 0.003). Significant drivers of residues and resistance emergence were antimicrobial misuse and overuse (OR = 2.72; 95% CI:1.93-3.83), non-enforcement of laws (OR = 2.98; 95% CI:2.11-4.21), poor education and expertise (OR = 1.52; 95% CI:1.09-2.12), and husbandry management system (OR = 10.24; 95% CI:6.75-15.54). The majority of intensive (63.6%) and semi-intensive (57.63%) farm systems belonged to Class 3 (Red risk) status. Antimicrobial residues were detected in 48.4% intensively and 34.4% semi-intensively managed farms. The study revealed poor practices of AMU in beef cattle production. Many factors were found to influenced antimicrobial residues and resistance occurrence and dissemination. A 'One Health' approach mitigation with adequate sanitation, hygiene, and good biosecurity measures will assure food safety, public and environmental health.

Occurrence and human health risk assessment of antibiotics in cultured fish from 19 provinces in China

The occurrence of antibiotics and potential health risk of 300 cultured fish samples from 19 provinces in China were investigated. The levels of 28 antibiotics (15 fluoroquinolones, 4 tetracyclines, 8 macrolides and rifampin) in 8 fish species were measured through liquid chromatography electrospray tandem mass spectrometry. As a result, 10 antibiotics were detected with an overall detection frequency of 24.3%, and the individual detection frequency of antibiotics ranged from 0.33 to 16.7%. The extremely high concentrations (above 100 µg/kg) of doxycycline and erythromycin were found in the samples. Antibiotics with high detection frequency was noticed in largemouth bass (41.2%), followed by snakehead (34.4%) and bream (31.2%). Specifically, Heilongjiang, Xinjiang, Qinghai and Gansu presented high detection frequency values of more than 60%. Moreover, the highest mean concentration was observed in Shandong, and the concentration covered from 34.8 µg/kg to 410 µg/kg. Despite the high detection frequency and levels of antibiotics were found in samples, ingestion of cultured fish was not significantly related to human health risks in China, according to the calculated estimated daily intakes and hazard quotients. These results provided us the actual levels of antibiotics in cultured fish and human health risk assessment of consuming fishery products.

Knowledge, Attitudes, and Risk Perception of Broiler Grow-Out Farmers on Antimicrobial Use and Resistance in Oyo State, Nigeria

Assessing knowledge, attitudes, and risk perception of Nigerian broiler grow-out farmers (n = 152) to antimicrobial resistance (AMR) with a five sectional purposive-structured-questionnaire: demographics; knowledge; attitudes; risk-perception; and response to regulation of antimicrobial practices. Data were analyzed using descriptive statistics, chi-square test, and binary logistic regression. Respondents’ knowledge score, in total, was lower than average, with all (100%) respondents having the understanding that antibiotics kill/reduce bacteria, most participants (>73%) believing that feeding antibiotics to broiler chickens is a necessity for weight gain, and many (>69%) thinking that no negative side-effects exist with the use of antibiotics. Poor attitude towards antimicrobial usage was prevalent (>63%) with unsatisfactory performance in most instruments: >60% of farmers reported using antimicrobials every week and still use antimicrobials when birds appear sick, and most (>84%) arbitrarily increase the drug dosages when used. However, a satisfactory performance score was reported (68%) in risk perception of AMR with >63% perceiving that inappropriate use of antibiotics is the main factor causing the emergence of resistant bacteria; >65.8% expressed that AMR in broiler chickens is not essential for public health, that AMR cannot develop from broiler bacteria diseases, that increasing the frequency of antimicrobial use cannot increase AMR in future, and that usage cannot lead to antibiotic residue in broiler-meat products leading to AMR development in human. None of the respondents were aware of any regulation for monitoring antimicrobial use. Significant factors associated with knowledge, attitudes, and risk perception of antimicrobial use and resistance among broiler grow-out farmers include marital status, farm category, education, educational specialization, sales target, growth duration/cycle, broiler stocking batch, and feed source. Identified gaps exist in AMR awareness among Nigerian broiler farmers and should be targeted through stakeholders’ participation in combatting AMR threats.