Antibiotics In Food-producing Animals Research Articles

Recent developments in antibiotic contamination of animal products, soil, and water worldwide

Abstract Antimicrobial resistance (AMR), facilitated by antibiotic consumption, remains one of the biggest threats to global health and food security. The burgeoning AMR has an estimated forecast of 10 million deaths and 100 trillion USD economic losses annually worldwide by 2050 if no urgent actions are taken. The indiscriminate use of antibiotics in food animal production plays an expressive role in the AMR crisis. This paper compiles information regarding antibiotics and AMR in animals, animal-derived products, and agriculture-impacted environment. A holistic approach is needed to mitigate the burden of AMR within the context of human-animal-environment. Currently there are few approaches to this problem such as nanotechnology, anaerobic digestion, biochar composting, and alternatives to antibiotic treatments (like herbal plant extracts, probiotics, vaccines, enzymes, and antimicrobial peptides) have been developed. However, there are gaps in knowledge about AMR and areas for improvement are obvious. There is no a clear path to put an end to the persistent trends of AMR. Despite the trends for stricter regulation on the use of antibiotics worldwide, they find their way into food animal production, water, and soil as a result of misuses in many countries. We need to acknowledge the antibiotic contamination and/or AMR as a silent pandemic, and we are challenged to adopt a global approach to reducing and improving their use.

AMR Threat Perception Assessment of Heterotrophic Bacteria From Shrimp Aquaculture Through Epidemiological Cut off Values.

Emergence and dissemination of antibiotic resistance is one of the major risks associated with the rampant usage of antibiotics in food-producing animals including aquaculture. To determine Epidemiological Cut-OFF (ECOFF) values of heterotrophic bacterial populations from shrimp culture environments against five different antibiotics. In this present study, bacterial samples were isolated from Penaeus vannamei culture environment in different locations of Andhra Pradesh, which is the aquaculture hub of India. The bacterial isolates were assessed for antibiotic resistance towards five antibiotics belonging to different classes (oxytetracycline, chloramphenicol, erythromycin, ciprofloxacin, and co-trimoxazole) by the disc diffusion method. Determination of Epidemiological Cut-OFF (ECOFF) values and analysis by employing normalized resistance interpretation (NRI) was carried out. The most dominant bacterial populations from shrimp culture were Vibrio spp. (pathogenic bacteria) followed by Bacillus spp. (probiotic bacteria). The bacterial isolates showed highest resistance towards oxytetracycline (overall 23.38%) and in location L6 (59.4%) followed by co-trimoxazole (31.1%). ECOFF values calculated by employing NRI showed that the disc diffusion data were distributed in a normalized manner. The maximum ECOFF value was obtained for ciprofloxacin (23.32 mm), while the minimum value was observed for oxytetracycline (9.05 mm). The antibiotic resistant phenotypes showed that the majority of the heterotrophic bacterial isolates (>60%) belonged to the non-wild type phenotype and primarily towards oxytetracycline (90%). The presence of non-wild antibiotic-resistant phenotypes of heterotrophic bacterial populations (which include not only pathogenic bacteria but also probiotic bacteria) indicates that shrimp culture ponds may be a reservoir for drug-resistant bacteria and there is a greater risk associated with transmission of resistant genes across bacterial flora. NRI analysis of antibiotic disc diffusion data of heterotrophic bacterial populations in shrimp aquaculture environments revealed that majority of them belonged to non-wild type (90%) paticularly to oxytetracycline in comparison to other studied antibiotics (chloramphenicol, erythromycin, ciprofloxacin and co-trimoxazole).

<i>In vivo</i> therapeutic evaluation of phage cocktail and probiotic in reducing <i>Salmonella </i>infection in Broilers

Antimicrobial resistance and ban on the usage of most of the antibiotics in food producing animals especially in poultry and pigs propelled research towards antibiotic alternatives. Food borne and multidrug-resistant (MDR) pathogens like Salmonella can enter food chain via consumption of the contaminated meat. Bacteriophage (phage) therapy could be used during rearing or pre-harvest stages of poultry production to overcome these emerging problems. The present study was conducted to determine the therapeutic effectiveness of bacteriophage cocktail and probiotics against Salmonella gallinarum in experimentally infected broiler chicks based on mortality, clinical manifestations, and faecal shedding. In vitro evaluation revealed that optical density (OD) of Salmonella gallinarum at MOIs of 102 was significantly reduced by individual phages as well as phage cocktail, with comparably less decrease in optical density in the culture treated with individual phage than the phage cocktail. Bacteriophage cocktail with concentration 1011 PFU/ml was able to protect 100% birds infected with Salmonella gallinarum. Faecal shedding rate was significantly low in the birds treated with bacteriophage cocktail and probiotics (1.2%) than untreated group. Significant improvement in body weight was seen in the bacteriophage treated groups as compared to untreated infected group. Based on the findings of the current study, administering high titre bacteriophages alone or in combination with probiotics for the effective management of Salmonella infection in broiler chicks may be suggested as an alternative to antibiotics as well as a useful strategy to control food borne pathogens in the food chain.

Residues of veterinary antibiotics in manures from pig and chicken farms in a context of antimicrobial use reduction by implementation of health and welfare plans

The use of antibiotics in food-producing animals can induce the presence of residual substances in manure, which are then released into the environment and may contribute to soil and groundwater contamination. During the on-farm implementation of strategies to improve animal health and welfare in chicken and pig farms, the consequences of antibiotic use were evaluated in terms of the occurrence and levels of antibiotic residues in manure.A set of 35 broiler farms from Cyprus, Greece, the Netherlands and 40 pig farms from France and Italy provided a total of 350 manure samples. The primary objective was to develop a specific LC/MS/MS method capable of quantifying antibiotic residues in both types of manure. The method was able to detect fifteen antibiotics belonging to nine classes, with validated limits of quantification of 10–20 μg/kg, and accuracies ranging from 81% to 138%.With the exception of amoxicillin, which was never detected in any manure, all antibiotics used were detected in manure from treated animals with typical concentrations ranging from 10 to 99198 μg/kg for both chickens and pigs. The occurrence of residual antibiotics was higher in chicken than in pig manure, especially for fluoroquinolones and doxycycline which were detected in 89% and 100% of the chicken manure, respectively, and in 28% of the pig manure. The impact of the health plans on the antibiotic load manure was assessed by measuring for each farm the ratio of the sum of all antibiotic concentrations measured after and before the implementation of the plan. The results showed that, in addition to the frequency of treatments, the class of antibiotic used is an important factor to consider as it strongly influences the stability/instability of the compounds, i.e. their ability to persist in the manure of food-producing animals.

수의사 처방제 전·후 가축에 대한 항생제 판매량

A veterinarian prescription system (VPS) was implemented in 2013 to reduce the use of antibiotics in food-producing animals in South Korea. To understand effects of VPS on sales of antibiotics for food-producing animals, this study compared average sales of antibiotics for seven years before (2006-2012) and after (2014-2020) implementing VPS using population correction unit (PCU). As a result, average sales (242 mg/PCU) after implementing VPS decreased by 36% compared to those (380 mg/PCU) before implementing it. In addition, average sales of HP-CIAs after implementing VPS decreased by 14% from 51.4 mg/PCU to 44.2 mg/PCU compared to those before implementing it. Although average sales of total antibiotics and HP-CIAs for food-producing animals decreased after implementing VPS compared to those before implementing it, they were still higher than those in Europe. Therefore, it is necessary to strengthen VPS continuously to reduce the use of antibiotics for food-producing animals in the future.

Impact of a Statewide Livestock Antibiotic Use Policy on Resistance in Human Urine Escherichia coli Isolates: A Synthetic Control Analysis.

On 1 January 2018, California implemented Senate Bill 27 (SB27), banning, for the first time in the United States, routine preventive use of antibiotics in food-animal production and any antibiotic use without a veterinarian's prescription. Our objective was to assess whether SB27 was associated with decreased antimicrobial resistance among E. coli isolated from human urine. We used U.S. nationwide monthly state-level data from BD Insights Research Database (Becton, Dickinson, and Co.) spanning 1 January 2013 to 30 June 2021 on antibiotic-resistance patterns of 30-d nonduplicate E. coli isolated from urine. Tested antibiotic classes included aminoglycosides, extended-spectrum cephalosporins (ESC), fluoroquinolones, and tetracyclines. Counts of tested and not-susceptible (resistant and intermediate, hereafter resistant) urine isolates were available by sex, age group (, year), month, and state. We applied a synthetic control approach to estimate the causal effect of SB27 on resistance patterns. Our approach created a synthetic California based on a composite of other states without the policy change and contrasted its counterfactual postpolicy trends with the observed postpolicy trends in California. We included E. coli urine isolates, 90% among women, across 33 states. From 2013 to 2017, the median (interquartile range) resistance percentages in California were 11.9% (7.4, 17.6), 13.8% (5.8, 20.0), 24.6% (9.6, 36.4), 7.9% (2.1, 13.1), for aminoglycosides, ESC, fluoroquinolones, and tetracyclines, respectively. SB27 was associated with a 7.1% reduction in ESC resistance (p-value for joint null: ), but no change in resistance to aminoglycosides, fluoroquinolones, or tetracyclines. Further research is needed to determine the role of SB27 in the observed reduction in ESC resistance E. coli in human populations, particularly as additional states implement similar legislation. https://doi.org/10.1289/EHP11221.

Consumers’ knowledge regarding antibiotic residues and their consciousness about food safety issues in livestock products

Intensification of the animal husbandry sector in India is overlapping with the increased administration of antibiotics in food-producing animals for therapeutic, prophylactic and growth promotion purposes. Now antibiotic residues are appearing in milk, meat, and eggs if the withdrawal period is not observed, leading to adverse effects on human health due to its consumption. Thus there is need to study the consciousness of consumers about food safety issues and their knowledge about antibiotic residues in livestock products. The present study has been conducted purposively in Telangana state by selecting 120 non-vegetarian consumers. The study revealed that respondents from the study area, preferred taste, followed by price over the other attributes while purchasing the livestock products. Antibiotic residues and hormone residues were the least considered attributes revealed by respondents. About 71% had low level of knowledge followed by medium about antibiotic residues in livestock products and antimicrobial resistance. Lack of concern and knowledge suggest low level of consumer awareness as well as consciousness about the potential risks associated with these residues on human health. Thus, there is need to provide adequate information and education amongst the general public about these emerging food safety issues.

Quantifying the Relationship between Antibiotic Use in Food-Producing Animals and Antibiotic Resistance in Humans.

It is commonly asserted that agricultural production systems must use fewer antibiotics in food-producing animals in order to mitigate the global spread of antimicrobial resistance (AMR). In order to assess the cost-effectiveness of such interventions, especially given the potential trade-off with rural livelihoods, we must quantify more precisely the relationship between food-producing animal antimicrobial use and AMR in humans. Here, we outline and compare methods that can be used to estimate this relationship, calling on key literature in this area. Mechanistic mathematical models have the advantage of being rooted in epidemiological theory, but may struggle to capture relevant non-epidemiological covariates which have an uncertain relationship with human AMR. We advocate greater use of panel regression models which can incorporate these factors in a flexible way, capturing both shape and scale variation. We provide recommendations for future panel regression studies to follow in order to inform cost-effectiveness analyses of AMR containment interventions across the One Health spectrum, which will be key in the age of increasing AMR.

In Vitro and In Vivo Evaluation of Lacticaseibacillus rhamnosus GG and Bifidobacterium lactis Bb12 Against Avian Pathogenic Escherichia coli and Identification of Novel Probiotic-Derived Bioactive Peptides.

Avian pathogenic E. coli (APEC), an extra-intestinal pathogenic E. coli (ExPEC), causes colibacillosis in poultry and is also a potential foodborne zoonotic pathogen. Currently, APEC infections in poultry are controlled by antibiotic medication; however, the emergence of multi-drug-resistant APEC strains and increased restrictions on the use of antibiotics in food-producing animals necessitate the development of new antibiotic alternative therapies. Here, we tested the anti-APEC activity of multiple commensal and probiotic bacteria in an agar-well diffusion assay and identified Lacticaseibacillus rhamnosus GG and Bifidobacterium lactis Bb12 producing strong zone of inhibition against APEC. In co-culture assay, L. rhamnosus GG and B. lactis Bb12 completely inhibited the APEC growth by 24h. Further investigation revealed that antibacterial product(s) in the culture supernatants of L. rhamnosus GG and B. lactis Bb12 were responsible for the anti-APEC activity. The analysis of culture supernatants using LC-MS/MS identified multiple novel bioactive peptides (VQAAQAGDTKPIEV, AFDNTDTSLDSTFKSA, VTDTSGKAGTTKISNV, and AESSDTNLVNAKAA) in addition to the production of lactic acid. The oral administration (108CFU/chicken) of L. rhamnosus GG significantly (P < 0.001) reduced the colonization (~ 1.6 logs) of APEC in the cecum of chickens. Cecal microbiota analysis revealed that L. rhamnosus GG moderated the APEC-induced alterations of the microbial community in the cecum of chickens. Further, L. rhamnosus GG decreased (P < 0.05) the abundance of phylum Proteobacteria, particularly those belonging to Enterobacteriaceae (Escherichia-Shigella) family. These studies indicate that L. rhamnosus GG is a promising probiotic to control APEC infections in chickens. Further studies are needed to optimize the delivery of L. rhamnosus GG in feed or water and in conditions simulating the field to facilitate its development for commercial applications.

An imaginary pandemic and its consequences

On June 30, 2021, findings from a report by the European Centre for Disease Prevention and Control (ECDC), the European Food Safety Authority, and the European Medicines Agency have shown that use of antibiotics in food-producing animals is decreasing in Europe.

Chemical Composition and Antibacterial and Antioxidant Activity of a Citrus Essential Oil and Its Fractions.

Essential oils (EOs) from Citrus are the main by-product of Citrus-processing industries. In addition to food/beverage and cosmetic applications, citrus EOs could also potentially be used as an alternative to antibiotics in food-producing animals. A commercial citrus EO—Brazilian Orange Terpenes (BOT)—was fractionated by vacuum fractional distillation to separate BOT into various fractions: F1, F2, F3, and F4. Next, the chemical composition and biological activities of BOT and its fractions were characterized. Results showed the three first fractions had a high relative amount of limonene (≥10.86), even higher than the whole BOT. Conversely, F4 presented a larger relative amount of BOT’s minor compounds (carvone, cis-carveol, trans-carveol, cis-p-Mentha-2,8-dien-1-ol, and trans-p-Mentha-2,8-dien-1-ol) and a very low relative amount of limonene (0.08–0.13). Antibacterial activity results showed F4 was the only fraction exhibiting this activity, which was selective and higher activity on a pathogenic bacterium (E. coli) than on a beneficial bacterium (Lactobacillus sp.). However, F4 activity was lower than BOT. Similarly, F4 displayed the highest antioxidant activity among fractions (equivalent to BOT). These results indicated that probably those minor compounds that detected in F4 would be more involved in conferring the biological activities for this fraction and consequently for the whole BOT, instead of the major compound, limonene, playing this role exclusively.

Antimicrobial-resistant non-typhoidal Salmonella enterica prevalence among poultry farms and slaughterhouses in Chitwan, Nepal

Background and Aim:Antibiotic-resistant infections are one of the leading threats to public health globally. Indiscriminate use of antibiotics in food animal production is an important driver of resistance, particularly among foodborne pathogens such as non-typhoidal Salmonella enterica (NTS). While there has been extensive research on antimicrobial-resistant (AMR) S. enterica in India and China, there have been few studies in countries in South Asia, including Nepal. This is particularly important with the rise of commercial poultry farming in Nepal as a means of economic development and nutritional subsistence. This descriptive study seeks to identify the prevalence and resistance patterns of NTS serotypes focusing on Chitwan, Nepal’s leading poultry producing district.Materials and Methods:A mixture of purposive and judgment sampling of 18 poultry farms and 20 slaughterhouses representing a broad geographic distribution across multiple municipalities in Chitwan was conducted in May 2019. Environmental samples taken from poultry farms included: Water, litter, feces, feed, farm swabs, and eggshell swabs. Biological samples taken from nearby slaughterhouses included: Muscle, heart, liver, skin, cecum, crop, and spleen. Samples were cultured and tested for the presence of NTS. Positive isolates were serotyped and tested for antimicrobial susceptibility to seven antibiotics known to be important to both human and animal health regionally. Farm practices were also characterized through a survey, the results of which are detailed in the accompanying paper.Results:Out of 708 samples (288 environmental and 420 biological), 103 (15%) tested positive for NTS (9% of environmental; n=26, 18% of biological; n=77). The percentage of positive environmental and biological samples varied by source. Environmental sample positive rates were water (27.5%), feces (10.6%), litter (8.6%), farm swabs (5%), feed (1.8%), and eggshells (0%). Biological sample positive rates were skin (28%), heart (23%), crop (20%), muscle (15%), liver (15%), spleen (15%), and cecum (12%). Out of 103 positive S. enterica isolates, 48.5% were identified as Salmonella Typhimurium, 35% Salmonella Enteritidis, 7.8% Salmonella Gallinarum, 4.9% Salmonella Virchow, and 3.9% were Salmonella Agona. Of the 103 positive isolates, 80 (78%) were resistant to at least one antibiotic, and 21 (20%) were multidrug-resistant (MDR).Conclusion:NTS is highly prevalent among Chitwan’s growing poultry industry with higher rates of positivity found in slaughterhouse samples compared with environmental samples from farms. In addition, a high rate of AMR (78%) was revealed, and an extremely concerning number of those were shown to be MDR (20%). This baseline data has important implications for poultry production and consumption in the region. Further research will elucidate the extent to which this contamination and drug resistance is impacting the health of the local population and help inform treatment and management strategies.Note: The characterization of the poultry industry and practices that might be linked to NTS contamination in the Chitwan district are detailed in the previous paper in this series (www.veterinaryworld.org/Vol.14/February-2021/14.pdf).

Characterization of Third-Generation Cephalosporin-Resistant Escherichia coli Isolated from Pigs in Cuba Using Next-Generation Sequencing.

Resistance to third-generation cephalosporins (3GC) in Escherichia coli has been reported worldwide from humans and animals, but the situation in Cuba is still poorly understood. This study aimed to gain new insights into the phenotypic and genotypic characteristics of third-generation cephalosporin-resistant (3GC-R) E. coli isolated from pigs in Cuba. Rectal swabs from 215 healthy pigs were taken from different municipalities in the western region of Cuba and spread on MacConkey agar supplemented with cefotaxime and ceftazidime. Ninety-six isolates were identified as 3GC-R E. coli and 87.5% of them were resistant to at least three antibiotic classes as determined by the measurement of the minimum inhibitory concentration (MIC) of 14 antibiotics. Twenty-seven different isolates were selected for Illumina next-generation sequencing, and subsequent in silico analysis was performed for the detection of antibiotic resistance and virulence genes, plasmid incompatibility (Inc) groups, multilocus sequence typing (MLST), and core genome MLST (cgMLST). The sequenced isolates contained extended-spectrum β-lactamase genes blaCTX-M-32 (n = 17), blaCTX-M-15 (n = 5), and blaCTX-M-55 (n = 4) as well as with pAmpC gene blaCMY-2 (n = 2). They also harbored genes for resistance to other clinically important classes of antibiotics, as well as several diverse virulence factors. The 3GC-R E. coli were genetically highly diverse, belonging to 16 different sequence types. IncX1 was the most frequent Inc group. The presence of 3GC-R E. coli in pigs from Cuba containing several different antibiotic resistance mechanisms emphasizes the need for surveillance programs and the establishment of strategies for the prudent use of antibiotics in food-producing animals.

Enhancing immunity level by using phytogenic feed additives in animal diets (review)

It is established that antibiotics are one of the most important medical discoveries of 20th century and will remain an utmost way of treating disease of animals as well as of human beings. We, the human beings, get meat, milk, egg, etc. from animals being very important and inevitable part of our daily nutrition. The irrational, consecutive and extensive use of antibiotics in food producing animals particularly for growth promotion has lead to antibiotic resistance, microbial resistance and possible the drug residual threat for human beings due to consumption of milk, meat, egg, etc. It was found out that during the normal physiology the animals undergo various types of stresses mainly including environmental, pathogenic, etc which suppress the immune system as well as the GIT of animals and due to this the animals become vulnerable to different diseases which leads to immunosuppression, poor health status, increased mortality and decreased production. Due to this ban on using synthetic antibiotics in animals as antibiotic growth promoters (AGP), an alternative approach is to use phytochemicals in animals’ feed for growth promotion, optimum production and enhancing or modulating the immunity level of animal. These phytogenic feed additives are important and have many properties i.e. anti-fungal, antibiotic, anti-inflammatory, antioxidant, antiviral, etc which, when supplemented with diet and fed to animals, ensure the protection and improvement of health condition, integrity of GIT and enhance the immunity level of animal. This review illustrates the importance of plant-based feed additives supplemented with other feedstuff and fed to animals particularly their role in immunomodulation to boost the immunity level on animal under stress conditions. Key words: feed additives, phytobiotics, alternative to antibiotics, animal feeding, immunity.

Antimicrobial resistance in fecal Escherichia coli isolated from poultry chicks in northern Iran

BackgroundThe use of antibiotics in food-producing animals has raised concerns about the spread of resistant bacteria. Antimicrobial resistance is achieved by horizontal gene transfer between bacteria or mobile gene elements in humans, animals and the environment.The present study was conducted to determine the prevalence and genetic diversity of antibiotic resistance in poultry-isolated E. coli in northern Iran. Materials and methodsOverall, 206 E. coli isolates were collected from the cloacal swabs of healthy Ross broiler chickens at 20–45 days of age from individual commercial broilers farms from August to December 2019. The antimicrobial susceptibility assessment was tested using disc diffusion for 20 antibiotics. PCRs were performed for investigating the respective antimicrobial resistance genes. ResultsAmong 206 fecal E. coli isolates, 89.81% were resistance to at least one antimicrobials tested, and 70.87% showed MDR phenotype. The highest resistance was related to Flumequine and Chlortetracycline. In accordance with phenotypic assay, tetA, tetB, qnrS and qnrB encoding for tetracyclines and quinolones resistance were the most predominant genes. IMP, VIM, GIM and SPM β-lactamase-encoding genes and colistin resistance-associated mcr genes were not detected in any phenotypically non susceptible isolates. ConclusionThe presence of different classes of resistance genes in poultry isolated E. coli strains suggests the importance of poultry-source E. coli in the distribution of drug resistance in humans in northern Iran.

Impacts on Livestock Producers and Veterinarians ofFDAPolicies on Use of Medically Important Antibiotics in Food Animal Production

AbstractU.S. Food and Drug Administration (FDA) policies fully implemented in 2017 ended the use of “medically important” (pertinent for human disease treatment) antibiotics for livestock growth promotion purposes. Between 2015 and 2017, medically important antibiotics sales for food animal production declined by 43%, after steady growth between 2009 and 2015. We examine the impacts of the antibiotics sales decline on livestock producers and veterinarians using case studies and empirical event studies. We find that the drop in sales did not impact overall meat production and that livestock producers engaged more heavily with their veterinarians to implement better management strategies.

Determinants influencing antibiotic use in Singapore's small-scale aquaculture sectors: A qualitative study.

Singapore’s Antimicrobial Resistance (AMR) national strategic action plan includes inappropriate use of antimicrobials in food-producing animals as a specific priority. Although the use of antibiotics and other drugs are monitored by regulatory bodies, food fish farmers are allowed to buy and administer antimicrobials without a veterinary prescription. We conducted a qualitative study of Singaporean food fish farmers to understand patterns and determinants of antibiotic use, their knowledge of antibiotic resistance, as well as perceptions of on-farm infection prevention and control measures. During the interview, participants were asked about their farming processes, farm infrastructure, antibiotic use and any disease prevention measures. Thematic analysis of participants’ interviews showed that antibiotic for growth promotion and infection prevention was uncommon among local food fish farmers. The following three main themes influenced participants’ decisions to use antibiotics in their practice: 1) individual factors, 2) local regulatory factors as well as 3) market-related factors. Individual factors included their personal experience and knowledge both with antibiotics as well as with alternate options. In terms of local regulatory factors, we found that regular oversight was a strong deterrent in antibiotic use. Last, at the market level, the relatively high price of antibiotics in Singapore coupled with stiff competition was a strong disincentive for participants to use antibiotics in their farming practice. These factors were also influential in their relationships with local regulatory bodies as well as their counterparts. Although industries differ significantly across countries, lessons learnt from Singapore’s food fish farming demonstrate the importance of an environment where multi-dimensional factors come together to discourage the irrational use of antibiotics in food animal production. In addition, our results allow greater insight into food fish farmers’ perspectives on infection control and form a basis from which further research work can be undertaken.

In-Depth Genomic Characterization of a Meropenem-nonsusceptible Pseudomonas otitidis Strain Contaminating Chicken Carcass

Background: The indiscriminate use of antibiotics in food-animal production has a major impact on public health, particularly in terms of contributing to the emergence and dissemination of antimicrobial resistant bacteria in the food-animal production chain. Although Pseudomonas species are recognized as important spoilage organisms in foodstuff, they are also known as opportunistic pathogens associated with hospital-acquired infections. Furthermore, Pseudomonas can play a role as potential reservoirs of antimicrobial resistance genes, which may be horizontally transferred to other bacteria. Considering that cephalosporins (3rd and higher generations) and carbapenems are critically important beta-lactam antimicrobials in human medicine, this study reports the occurrence and genomic characterization of a meropenem-nonsusceptible Pseudomonas otitidis strain recovered from a chicken carcass in Brazil.Materials, Methods &amp; Results: During the years 2018-2019, 72 frozen chicken carcasses were purchased on the retail market from different regions in Brazil. Aliquots from individual carcass rinses were screened for Extended Spectrum Beta-lactamase (ESBL)-producing bacteria in MacConkey agar supplemented with 1mg.L-1 cefotaxime. Phenotypically resistant isolates were further tested for resistance to other antimicrobials and confirmed as ESBL-producers by means of disk-diffusion method using Müller-Hinton agar. Only one meropenen-nonsusceptible isolate was detected and submitted to whole genome sequencing (WGS) in Illumina Miseq. The strain was identified as Pseudomonas otitidis by local alignment of the 16S rRNA sequence using BLASTn and confirmed by Average Nucleotide Identity (ANI) analysis using JspeciesWS database. Genes encoding for antimicrobial resistance were detected by means of Resfinder and Comprehensive Antibiotic Resistance Database (CARD) databases. The phenotypic non-susceptibility to meropenen was attributed to the gene blaPOM-1. A total of 192 different genes encoding for quorum sensing system, antiphagocytosis, iron uptake, efflux pump, endotoxin and toxin, adherence, and secretion systems were detected by means of Virulence Factor Database (VFDB). Pseudomonas otitidis-pan genome was built using Roary-rapid large-scale prokaryote pan genome analysis using the present strain (K_25) and other two P. otitidis genomes (PAM-1, DSM 17224) publicly available at the NCBI. The core genome analysis of the two human strains resulted in similar percentages.Discussion: Carbapenems are critically important drugs for human health and bacterial strains resistant to these antimicrobials pose a public health problem. The blaPOM-1 gene harbored by the Pseudomonas otitidis K_25 strain encodes a metallo-beta-lactamase (MBL) conferring resistance to carbapenems. Pseudomonas otitidis was the first confirmed pathogenic Pseudomonas species expressing MBL constitutively in the absence of inducible beta-lactamase genes. Furthermore, the several virulence genes associated with the capacity of the P. otitidis K_25 to colonize, evade the immune system and cause lesions in the human host confirm this strain as a potential opportunistic pathogen contaminating foodstuff. These reinforce the need to address antimicrobial resistance in a One Health perspective, in which resistant bacteria and resistance determinants circulate among environment, animals and humans.

Mitigating Antibiotic Resistance at the Livestock-Environment Interface:A Review.

The rise of antimicrobial resistance (AR) is a major threat to global health. The food animal industry contributes to the increasing occurrence of AR. Multiple factors can affect the occurrence and dissemination of AR in the animal industry, including antibiotic use and farm management. Many studies have focused on how the use of antibiotics in food-producing animals has led to the development of AR. However, a few effective mitigating strategies for AR have been developed in food-producing animals, especially those exposed to the environment. The aim of this review is to summarize potential strategies applicable for mitigating AR at the environment-livestock interface.

623. Antimicrobial Resistance in Non-Typhoidal Salmonella from Retail Poultry Meat by Antibiotic Usage-related Production Claims—Pennsylvania, 2008–2017

BackgroundAntimicrobial-resistant (AMR) nontyphoidal Salmonella infections are a public health concern. Injudicious use of antimicrobials fuels emergence of resistance. The National Antimicrobial Resistance Monitoring System (NARMS) tracks AMR in Salmonella from humans, animals and foods. There is limited evidence regarding antimicrobial use in food animals and AMR bacteria in retail meat.MethodsWe reviewed antimicrobial susceptibility and whole-genome sequencing data from 320 Salmonella isolated from poultry meat in Pennsylvania as part of NARMS activities. Salmonella strains were isolated from 3,481 samples purchased from randomly selected retail outlets during 2008–2017. Antibiotic usage claims on meat packages were used to compare AMR Salmonella from conventional and antibiotic-free/organic (Abx-free) samples. Genetic mechanisms for AMR were investigated in a subset of isolates.ResultsThe prevalence of Salmonella in conventional poultry meat 10.2% (280/2,733) was significantly higher than the prevalence in poultry meat labeled as Abx-free (5.3%, 40/748; P < 0.0001). Salmonella from conventional poultry meat was more likely to be resistant to 3 or more drugs (55.0%, 154/280) compared with poultry meat labeled as Abx-free (27.5%, 11/40; P = 0.0011). Salmonella from conventional poultry exhibited significantly higher resistance to 4 drug classes including β-lactams (P = 0.006) (figure). One hundred isolates from conventional poultry meat and 8 isolates from antibiotic-free/organic samples harbored a gene conferring resistance to the β-lactam class; 24.3% (68/280) of isolates from conventional and 7.5% (3/40) of isolates from Abx-free samples (P = 0.0145) contained the extended-spectrum β-lactamase (ESBL) gene blaCMY-2.ConclusionMeat samples from conventionally-raised poultry were more likely to be contaminated with AMR Salmonella strains and have genes that reduce the effectiveness of antimicrobial drugs recommended for treatment of severe infections. Contamination of poultry with AMR Salmonella strains is concerning as is the presence of genes that decrease the power of critical antibiotics such as β-lactams. These findings highlight the importance of judicious use of antibiotics in food-producing animals. Disclosures All authors: No reported disclosures.