Screening for tylosin and other antimicrobial residues in fresh and fermented (nono) cow milk in Delta state, South-South, Nigeria

Occurrence, antimicrobial resistance, and molecular characterization of Salmonella enterica from chicken products and human in Wasit Governorate of Iraq

Background

Salmonella infections are considered the most common foodborne pathogens responsible for zoonotic infections and food poisoning in humans and animal species such as birds. Antimicrobial resistance is considered a global anxiety because it causes human public health repercussions, as well as leads to an increase in animal morbidity and death.

Aim

The aims of this study are the isolation and identification of Salmonella enterica, as well as to investigate the antimicrobial susceptibility test (AST) and the molecular characteristics using polymerase chain reaction (PCR) and sequences for isolates from chicken products (eggs, livers, and minced meat) and human in the Wasit Governorate of Iraq.

Methods

A total of 300 samples (150 chicken product samples including eggs, livers, and minced meat, and 150 human fecal samples) were collected from the Wasit governorate of Iraq from January to December 2022. The bacterial isolation was done according to recommendations of ISO 6579 standard and the Global Foodborne Infections Network laboratory protocol. Serotyping test and AST were done by using 19 antibiotic agents according to the recommendations of the Clinical and Laboratory Standards Institute, 2022 by using disc diffusion susceptibility test and Vitik 2 test. Finally, the suspected isolates were confirmed using the conventional PCR method and sequencing for a unique rRNA gene.

Results

The results showed that the isolation percentage of S. enterica in chicken products was 8.66% (12% eggs, 6% livers, and 8% minced meat), while in humans it was 4.6%. Also, showed 100% of Salmonella typhi in humans. While, in chicken eggs S. typhi, Salmonella typhimurium, and Salmonella enteritidis were 50%, 33.33%, and 16.66%, respectively. Also, showed 100% of S. typhimurium in both livers and minced meat. The AST in human isolates showed resistance to Ampicillin, Cefotaxime, Ceftazidime, Cefepime, Amikacin, Gentamicin, Ciprofloxacin, Norfloxacin, and Ceftriaxone, while no resistance to Amoxicillin, Pipracillin, Ertapenem, Imipenem, Meropenem, Fosfomycin, Nitrofurantoin, Trimethoprim, Azithromycin, and Tetracycline. In chicken products, isolates were resistant with different percentages to Amikacin, Gentamicin, Tetracycline, Ciprofloxacin, Norfloxacin, Nitrofurantoin, Ampicillin, Cefotaxime, Ceftazidime, Cefepime, and Trimethoprim; while no resistance to Amoxicillin, Pipracillin, Ertapenem, Imipenem, Meropenem, Fosfomycin, Azithromycin, and Ceftriaxone. Sequencing by using rRNA gene was done for four PCR products.

Conclusion

This study showed the presence of genetic mutations for S. enterica which led to variations in the molecular characteristics, and antimicrobial drug resistance of S. enterica isolated from chicken products and humans.

Assessment of antibiotic residues in chicken meat

Background

Nowadays veterinarians and poultry producers use antibiotics to increase growth rates, bird health, and feed efficiency, egg production, for preventative and therapeutic purposes, and to lessen the prevalence of poultry diseases. Most poultry producers have used a variety of antibiotics, either with or without veterinarian instruction. Although antibiotics are beneficial for the majority of their uses, their unauthorized use has resulted in residues accumulated in poultry products intended for human consumption which represents a serious risk to the general public that could be toxicological, microbiological, or immunological.

Aim

This study aimed to the estimation of the residues of three major antimicrobials used in the intensive chicken-rearing systems in Egypt, namely Oxytetracycline (OTC), Gentamicin, and Ciprofloxacin. Moreover, the effect of cooking on such residues was investigated.

Methods

A total of 100 chicken meat samples (breast, thigh, gizzard, liver, 25 each) were examined for detection of the aforementioned antimicrobials using the microbial inhibition assay and high-performance liquid chromatography (HPLC). Besides, samples containing the highest antimicrobial residues were examined for the effect of boiling for 30 minutes on such residues.

Results

The obtained results revealed that 23%, 21%, and 17% of the examined samples were positive for OTC, gentamicin, and ciprofloxacin residues , respectively . Cooking (boiling) for 30 minutes showed a reduction of the antibiotic residue by 88.2%, 95.2%, and 31.3%, respectively.

Conclusion

Antimicrobial residues were detected in the chicken meat parts retailed in Egypt. Cooking can reduce the antimicrobial residues at least in part.

Validation and application of an immunochromatographic test to detect four macrolides and two lincosamides in raw cow milk

In this study, an immunochromatographic test (using the Charm QUAD2® Test) was used to screen for residual macrolides and lincosamides in raw cow's milk. The validation parameters (selectivity/specificity, detection capability (CCβ), and ruggedness) were in agreement with the requirements of[EC] 2021. The selectivity of the immunochromatographic test was verified by the negative results of microbiological tests. The false-positive rate was 0%. The CCβ values of the immunochromatographic test for various antibiotics in milk were as follows: erythromycin 0.02 mg/kg, spiramycin 0.1 mg/kg, tilmicosin 0.025 mg/kg, tylosin 0.05 mg/kg, lincomycin 0.15 mg/kg, and pirlimycin 0.15 mg/kg. The determined CCβ values were lower than the respective maximum residue limits (MRLs; regulatory limits in Japan) for milk, except for lincomycin (equal to the MRL). The presence of antibiotic groups other than macrolides and lincosamides did not interfere with the specificity of the test. It showed no significant difference in lot-to-lot repeatability. The results obtained by the two researchers showed no significant differences. Finally, the test was applied to milk samples obtained from a tylosin-treated cow. The outcome was positive and in agreement with the results of the chemical analytical and microbiological methods. Therefore, this validated immunochromatographic test is expected to be suitable for routine analysis to ensure milk safety.

Simultaneous Screening of Six Families of Antibiotic Residues in Milk Samples by Biochip Multi-array Technology

Background

Antimicrobial compounds are used in animal husbandry to prevent and treat bacterial diseases and as illegal growth-promoting agents. Due to the excessive and inappropriate use of antibiotics, the antibiotic residues in milk can cause allergic reactions and antibiotic resistance. A rapid biochip-based method for the multi-analyte screening of 6 families of antibiotic residues (quinolones, ceftiofur, florfenicol, streptomycin, tylosin, and tetracyclines) in milk was validated based on Commission Decision 2002/657 and the European guidance for screening methods for veterinary medicinal products.

Methods

This methodology allows the 6 antibiotic families to be detected simultaneously, increasing the screening capacity and reducing costs in test settings. The method's applicability was shown by screening 38 UHT cow milk samples taken from Tehran province, IR Iran.

Results

The results showed that the positive threshold T was above Fm, and the CCβ was below the European Commission's Maximum Residue Limit (MRL) (100 ppb for ceftiofur and tetracycline and 50 ppb for tylosin in milk). Norfloxacin was detected in about 8% of the samples and tylosin in 2.63%. The total antibiotic concentration in UHT cow milk samples was lower than the European Commission's MRL.

Conclusions

This study showed that the biochip technique is valid for screening tylosin, ceftiofur, streptomycin, tetracycline, norfloxacin, and florfenicol in milk. It was found that the method was easy, quick, and capable of detecting 6 families of antibiotic residues simultaneously from a single milk sample without sample preparation.

Dietary Exposure to Antibiotic Residues Facilitates Metabolic Disorder by Altering the Gut Microbiota and Bile Acid Composition

Antibiotics used as growth promoters in livestock and animal husbandry can be detected in animal-derived food. Epidemiological studies have indicated that exposure to these antibiotic residues in food may be associated with childhood obesity. Herein, the effect of exposure to a residual dose of tylosin-an antibiotic growth promoter-on host metabolism and gut microbiota was explored in vivo. Theoretical maximal daily intake (TMDI) doses of tylosin were found to facilitate high-fat-diet-induced obesity, induce insulin resistance, and perturb gut microbiota composition in mice. The obesity-related phenotypes were transferrable to germfree recipient mice, indicating that the effects of a TMDI dose of tylosin on obesity and insulin resistance occurred mainly via alteration of the gut microbiota. Tylosin TMDI exposure restricted to early life, the critical period of gut microbiota development, altered the abundance of specific bacteria related to host metabolic homeostasis later in life. Moreover, early-life exposure to tylosin TMDI doses was sufficient to modify the ratio of primary to secondary bile acids, thereby inducing lasting metabolic consequences via the downstream FGF15 signaling pathway. Altogether, these findings demonstrate that exposure to very low doses of antibiotic residues, whether continuously or in early life, could exert long-lasting effects on host metabolism by altering the gut microbiota and its metabolites. IMPORTANCE This study demonstrates that even with limited exposure in early life, a residual dose of tylosin might cause long-lasting metabolic disturbances by altering the gut microbiota and its metabolites. Our findings reveal that the gut microbiota is susceptible to previously ignored environmental factors.

Screening of antibiotic residues in raw milk of cows and buffalos by diffusion assays

Although antibiotics are valuable drugs for treatment of certain infections, their presence in foodstuff derived from animals is a potential public health hazard. They pose a serious threat as they are implicated in direct toxicity; allergic reactions; disturbance of the normal gut microbiota, carcinogenesis, and emergence of antibioticresistant bacteria. This study investigated the occurrence of antibiotic residues in raw milk samples derived from cows and buffaloes. Samples were collected randomly from different retail outlets in Erbil city (Iraq) from January 1^st to June 30^th, 2019. The residues were detected by two diffusion assays against Bacillus subtilis bacteria on agar plates. The total occurrence of residues ranged from 11.9% to 13.4% of screened milk samples. No significant differences were found between milk type or location of animal rearing (urban or suburban). Regarding the seasonal variations, spring was found to be associated with gradual decrease in antibiotic residues levels in milk. Such occurrence rate of residues is alarming and require authorities to observe the quality of raw milk introduced to markets for consumption. Further evaluation of antibiotic stability period in raw milk is also necessary.

Assessment of Foodborne Disease Hazards in Beverages Consumed in Nigeria: A Systematic Literature Review

Risk assessment is a formal process of identifying hazards and assessing the risk associated with them (risk is a combination of the severity of illness and the probability of occurrence). This review highlights foodborne disease hazards reported in beverages consumed in Nigeria for the period between 2000 and 2020. Based on a preregistered protocol and search syntax, studies were retrieved from the PubMed, Google Scholar, and ScienceDirect databases. Rayyan QCRI software was used to screen the articles. Data were then extracted from the included full-text articles, into a standardized excel workbook. A total of 18,762 articles were identified, from which 126 were included in the final analyses. The common beverages studied were sachet water (14.9%), borehole/well water (13.9%), cereal-based beverages (12.1%), raw/fresh milk (8.3%) and nono/nunu, which is a fermented milk-cereal beverage (7.2%). Sufficient data were available to undertake pooled prevalence estimates for some hazards within select beverages and revealed contamination rates for Staphylococcus spp. in raw/fresh milk, 12.3% (95% CI 6.3–20.0); Salmonella spp. in borehole/well water, 19.8% (95% CI 13.1–27.4); Klebsiella spp. in sachet water, 40.0% (95% CI 12.4–71.7); Staphylococcus spp. in nono/nunu, 32.6% (95% CI 14.7–53.8), and Escherichia spp. in nono/nunu, 30.7% (95% CI 21.9–40.2). Heterogeneity was present in the aggregate summary estimates. This review has highlighted the presence of several hazards of high importance to public health in commonly consumed beverages in Nigeria. The data presented here provide an entry point for future quantitative risk assessments both to determine the level of exposure of the community to these hazards and also for the identification of the most effective mitigation strategies to reduce these risks and improve health outcomes in Nigeria.