Review Article - Journal of Clinical and Experimental Toxicology (2017) Volume 1, Issue 1
Antimicrobial resistance: An agent in zoonotic disease and increased morbidity.Elaine Meade1,2, Mark Anthony Slattery3, Mary Garvey1,2,3*
- *Corresponding Author:
- Dr Mary Garvey
Department of Life Science, Institute of Technology Sligo, Ash lane, Sligo, Ireland
Tel: +071 9305529
E-mail: [email protected]
Accepted date: December 29, 2017
The emergence of antibiotic resistant organisms is a significant challenge where increasing numbers of bacterial species are now showing multidrug resistance. At government level, there is a global incentive to develop novel therapeutic options; however, the development of new antibiotic agents will undoubtedly be followed by the emergence of resistance to these compounds, implying that the use of antibiotics is unsustainable. Currently there is a lack of new antibiotic options available for use especially against Gram negative pathogens. Reduction in the use of antibiotics and the prevention of infection therefore, may prove the most useful method to combat the issue. The use of antibiotics for veterinary applications as therapeutic, prophylactic, metaphylactic and as animal growth promoters has greatly proliferated the problem. The presence of sub-therapeutic levels of antibiotics in water ways from both agriculture and aquaculture encourages the expression of drug resistance. Furthermore, their high water solubility, extensive half-lives and constant use means that they persist in the environment, having repercussions for human and ecological health. The use of antibiotics from an early age may also have a negative impact on human morbidity with potential to contribute to obesity, dysbiosis and target organ toxicity of the liver and kidneys. This review aims to discuss three main concerns 1) the extensive use of antibiotics for veterinary and its impact on the emergence of resistance, 2) the occurrence of zoonotic disease particularly with resistant strains and 3) the relationship between both aquatic and food pollution and human morbidity.
antibiotic resistance, veterinary, public health, food pollution.
Antimicrobial resistance (AMR) and its relationship to human and animal morbidity is one of the biggest challenges facing modern medicine. The extent of the problem is now so great that the World Health Organisation (WHO) has published a priority list of antibiotic resistant pathogens based on critical, high and medium risk. The emergence of antimicrobial resistance in bacterial species is an evolutionary process which has been proliferated by the improper use and overuse of therapeutic agents. Over the counter purchasing and prescribing antibiotics where bacterial species are not the causative agent of disease are both major contributors to AMR. Moreover, the use of antimicrobials in veterinary medicine for disease treatment and prevention in both domestic and non-domestic animals also contributes significantly to the issue. Additionally, antibiotics (ABs) are widely used as growth promoters in aquaculture  and for promoting the faster growth of livestock in agriculture . Bacterial species gain antibiotic resistance through several mechanisms such as mutational alterations of antibiotic targets, changes in cell permeability, drug efflux and horizontal gene transfer coding for resistance . The prolonged infection of patients not responsive to therapeutic treatment is a serious health hazard resulting in extended hospital stay, increasing economic costs while also increasing the spectrum of resistance as more and more drug types are prescribed. Studies have shown that almost 70% of categorised nosocomial infections are resistant to at least one clinically relevant antibiotic  with many strains exhibiting multidrug resistance (MDR) to many classes of antibiotics. Furthermore, the nature of the bacterial resistance mechanisms of pathogens means that AMR and MDR will remain an on-going problem even with the development of new chemotherapeutic agents. For this reason, it is important to look at ways to control and reduce the spread of such pathogens where possible. The transmission of pathogenic and resistant bacterial species to human hosts from companion animals plays an important role in human morbidity. Zoonotic transmission and disease presents as an area that may allow for some improvement or reduction in the rate of emerging resistant species. For this reason, this review aims to outline the predominant resistant species associated with veterinary clinics and the role of AMR in zoonotic disease.
Mode of Resistance
The modes of resistance for the most relevant zoonotic species are outlined in Table 1 for antibiotics commonly employed for veterinary uses.
|Antibiotic||Modes of Resistance||Resistant Strains||References|
|Inhibition of Cell Wall Synthesis|
Natural: penicillin G, penicillin V
amoxicillin, ampicillin, carbenicillin Cephalosporins:
1st- generation cephalosporins:
3rd - generation cephalosporins:
Cefovecin, cefpodoxime, ceftiofur
4th- generation cephalosporins:
Primaxin Beta-lactamase inhibitors:
Clavulanic acid, sulbactam
|Production of β-lactamases i.e. Enzymatic degradation; Alteration of new penicillin binding proteins (PBP); Decreased uptake i.e. Porin channel formation is decreased Bind β-lactamase enzymes||Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa,
Salmonella Typhimurium DT 104, (ESBL)-producing Enterobacteriaceae, Enterococcus faecium, Pasteurella spp., Brucella spp.,
Staphylococcus aureus, Clostridium difficile, Campylobacter spp.
|   |
|Inhibition of cell membrane function|
|Colistin (Polymixin E), Polymixin B|| Lipopolysaccharide (LPS) modifications -
covalent modifications of the lipid A moiety of LPS Drug efflux
|Enterobacteriaceae spp.;Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Salmonella enterica, Acinetobacter baumannii||
|Inhibition of Protein Synthesis|
Tylosin and spiramycin,
|Target site modification i.e. binding to the 50S subunit of the ribosome Horizontal Gene transfer Drug efflux||Enterococci spp. (E. faecalis,E. faecium), Campylobacter spp,
Pasteurella multocida, Mannheimia haemolytica, Bartonella spp.,
Most gram-negative organisms
Clindamycin and Pirlimycin
|Target site modification i.e. binding to the 50S subunit of the ribosome Horizontal Gene Transfer Drug efflux||Campylobacter spp., Pseudomonas aeruginosa, Acinetobacter, Staphylococci, Enterococci, Pasteurella multocida, Mannheimia haemolytica, Escherichia coli,
|Cell membrane modification - decreased permeability Alterations at the ribosomal binding sites Production of aminoglycoside modifying enzymes (AMEs). Drug efflux||Salmonella Typhimurium DT 104, Klebsiella spp., Acinetobacter baumanii, Escherichia coli, Pasteurella spp., Campylobacter spp., S. aureus, Enterococci spp. (E. faecalis)||    |
|Chloramphenicol||Target site modification i.e. binding to the 50S subunit of the ribosome Enzymatic inactivation by acetylation by chloramphenicol acetyltransferases (CATs) Drug efflux||S. aureus, Salmonella Typhimurium DT 104, Pseudomonas aeruginosa, Proteus spp., Klebsiella spp, Campylobacter spp., Escherichia coli, Enterococci spp. (E. faecalis)|| |
|Florfenicol (fluorinated analog of thiamphenicol)||Target site modification Drug efflux - Over-expression of antimicrobial efflux pumps Horizontal Gene Transfer i.e. Acquisition of transferable resistance determinants||S. aureus, Salmonella Typhimurium DT 104, Klebsiella spp., Acinetobacter spp., Escherichia coli, Pasteurella piscicida
|Protection of ribosomes Enzymatic inactivation Drug efflux||Pasteurella spp., Pseudomonas spp., S. aureus
Salmonella Typhimurium DT 104, Brucella spp., Campylobacter spp., Klebsiella spp., Escherichia coli, Acinetobacter baumanii, Enterococci spp. (E. faecalis)
|   |
|Inhibition of DNA Function|
|Quinolones & Fluoroquinolones|
|Ciprofloxacin, Danofloxacin, Difloxacin, Enrofloxacin, Marbofloxacin, Norfloxacin, Orbifloxacin, Pradofloxacin||Mutational alterations in target enzymes – DNA gyrase and topoisomerase IV Horizontal gene transfer Drug efflux||Escherichia coli, E. faecium, Neisseria gonorrhoeae, Campylobacter spp (C. jejuni and C. coli),
Salmonella Typhimurium DT 104,Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumanii
|   |
|Sulfadiazine, Sulfamethoxazole, Sulfadoxine||Alteration of Enzyme (dihydropteroate synthetase) Over-production of para-aminobenzoic acid (PABA) - inhibition of dihydropterate synthetase enzyme Horizontal gene transfer||Pasteurella spp.
Salmonella Typhimurium DT 104
Neisseria meningitidis, Pseudomonas aeruginosa, Campylobacter spp., Bacillus spp., Escherichia coli, Shigella., Klebsiella
|   |
Table 1: Summarising the modes of resistance of species relevant to zoonosis and the veterinary application of antibiotics.
Resistance in Veterinary
The use of antibiotics in the veterinary industry relates to the treatment of animals and to the production of animal based food products. Agricultural use of antibiotics can be categorized into four uses: therapeutic use, prophylactic use for disease prevention, metaphylactic use for infection control and as animal growth promoters (AGPs) . For these purposes food-producing animals are given the same classes of antibiotics used for human therapeutics increasing the emergence of resistant bacterial species to the antibacterial agents.
Agriculture and Aquaculture Use of Antibiotics
Some of the most commonly used antibiotics in veterinary include tetracyclines as growth promoters and therapeutics in cattle, beta-lactams, chepalosporins and macrolides for disease treatment and growth enhancement and peptidomimetics as growth promoters in poultry . In the 1980s the first older generation quinolones (oxolinic acid and flumequine) were licensed for use in food producing animals, with fluoroquinolones being used as growth promoters in the late 1980’s and early 1990’s. This use of antibiotic agents means that large amounts of antibiotics and their metabolites which may still be active are excreted by the animals daily . The presence of these active antibacterial agents may then have effect on the micro biota of the soil, enter ground water, be re-consumed by livestock and/or gain entry to drinking water supplies. The spreading of animal manure as a fertiliser also contributes to this antibiotic pollution as it harbours large numbers of potentially resistant bacteria and is prone to agricultural run-off in to surrounding waterways. Furthermore, the nutrients present in the manure stimulate microbial growth and horizontal gene transfer between the different species present . The use of antibiotics in aquaculture is to control infection and to increase productivity, where salmonids, catfish and lobsters are given FDA approved drugs such as sulfadimethoxine, ormetoprim, and oxytetracycline via medicated feeds . The sub-therapeutic concentrations of these antibiotics used in aquaculture are mostly encountered after their prophylactic use . This sub-therapeutic concentration means that fish feed and faeces present in the surrounding aquatic environment allows for the promotion of AMR by exposing bacteria to low concentrations that can select for resistance. Furthermore, fish do not metabolise antibiotic drugs effectively and so excrete them in their active form into the environment. The presence of antibiotic agents in the meat from harvested fish and other farmed animals is now a reality as drug residues persist in animal tissues  resulting in contaminated food supplies and increase in AMR.
Emergence of AMR in Veterinary
Bacterial species associated with agriculture food producing animals and are Campylobacter jejuni, Salmonella enterica, Typhimurium DT104, and E. coli O157:H7 . Salmonella and Vibrio are potential pathogens associated with aquaculture with Listeria monocytogenes, Aeromonas, and Clostridium spp. being recognised as emerging threats . The use of fluoroquinolones particularly ciprofloxacin in poultry production since 1995 led to the emergence of ciprofloxacin resistant bacteria Campylobacter, which was subsequently detected in the breast meat of sacrificed animals. The antibiotic avoparcin which is used as an AGP in veterinary is believed to also promote vancomycin resistance, with the AGP antibiotic vinginicmycin having a similar affect with streptogramin which is used for human medicine . Cross resistance such as this occurs when a specific drug influences bacterial resistance and susceptibility to other antibiotics and happens regularly between antibiotics of the same class e.g. resistance between extended spectrum b-lactamases (ESBLs) caused cross-resistance within the class of penicillins and cephalosporins . Resistance modes of action based on altered efflux pumps and enzymatic degradation via gene sharing enables this cross resistance to occur over different classes of antibiotics, allowing resistance mechanisms developed to antibiotics solely used in veterinary to proliferate AMR to other antibiotics classes. Ceftiofur and cefquinome are third and fourth generation cephalosporin’s exclusively used as veterinary medicines  for the treatment of mastitis caused by Staphylococcus aureus, with ceftiofur also used prophylactically in piglets to prevent arthritis, meningitis, septicemia, and diarrhea . This use of cephalosporins has resulted in the emergence of ESBL producing E. coli which is transmissible to human hosts via excretion into the environment. Colistin also known as polymyxin E is an antibiotic used for the treatment of MDR gram negative pathogens and specifically for the carbapenemase producing Enterobacteriaceae since the 1990s. Colistin was banned from human use in the 1970s due to its nephrotoxic effect on the kidneys but remained in use as prophylactic and as a growth promoter in pigs . Resistance to colistin has now emerged in Klebsiella pneumonia, an important human pathogen that causes hospital-acquired and communityacquired infections .
Treatment Options and Methods to Reduce AMR
To reduce the proliferation of AMR the European Union (EU) banned the agricultural use of antibiotics as growth promoters in 2006. The dose administered for this purpose is typically sub-therapeutic and as a result serves to promote resistance in bacterial species. In countries such as America, Canada and Asia however, this ban has not been implemented where antibiotics are continually used for agricultural purposes . Indeed, in developing countries such as China and India where the use of antibiotics is not regulated and antibiotics are supplied as over the counter (OTC) medicines the rates of resistance are high . Furthermore, the use of quinolones for aquaculture was banned in several industrialized countries, as AMR to one type of quinolone typically results in resistance to all members of this class of antibiotics . Reducing antibiotic pollution caused by both agriculture and aquaculture will aid in reducing the number of environmental bacteria having acquired resistance mechanisms. In the EU an environmental risk assessment (ERA) is compulsory for therapeutics with an expected environmental concentration exceeding 10 ng/L with 100 ng/L being the ERA in the USA . There is a need for novel antibiotic agents which have effect on the already AMR and MDR strains however; undoubtedly resistance mechanisms will emerge to any new therapeutic developed. Additionally, exposure to sub-therapeutic levels of antibiotics interferes with some important physiological processes of bacterial cells which can result in changes in bacterial virulence as well as resistance  increasing their pathogenicity. The use of efflux pump inhibitors given in conjunction with AB agents can prevent resistance by interfering with the proton motive force of the resistant strain or by competing with the binding site of the pump itself . Research at present is ongoing assessing the potential for nanomaterials such as titania dioxide (TiO2) and graphene oxide (GO) as antimicrobial surface coatings . The application of bacteriophages as antibacterial agents is also a possibility as phage’s causes specific bacterial cell death while not affecting the animal host.
Zoonotic Disease Transmission of AMR
Summarising incidents of zoonotic disease from veterinary AMR bacterial and fungal species in Table 2.
|Antibiotic||Use in Veterinary||AMR||Zoonotic Disease||References|
|β-lactams; Cefotaxime, Cephalexin
Macrolides; Erythromycin, Clarithromycin, Tylosin, Azithromycin, Ketolides e.g., telithromycin
Aminoglycoside; Kanamycin, Gentamicin
Chloramphenicol Streptogramin B
Quinolones/Fluoroquinolones; Ciprofloxacin, Norfloxacin, nalidixic acid
|T, P, GP
T, P, GP
T, P, GP
T, P, GP
T, P T, P, GP
T, P, GP T, P, GP
E. coli and C. jejuni
||   |
|β-lactams; Amoxicillin-Clavulanic acid, Ampicillin, Cephalothin; Cefotaxime
Aminoglycoside; Gentamicin, Streptomycin; Kanamycin;
Sulphonamides; Sulfamethoxazole; Trimethoprim-sulfamethoxazole;
|T, P, GP
T, P, GP
T, P T, P, GP
T, P, GP T, P
|Verocytotoxin (VT)/Shigatoxin (ST)-producing Escherichia coli (VTEC/STEC);
E. coli O157:H7 (most common)
|Haemorrhagic colitis (HC); Thrombo-cytopenia; Haemolytic uremic syndrome (HUS)||
|β-lactams; ampicillin, cephalothin, amoxicillin-clavulanic acid, cefmetazole, cefotaxime; Penicillin G,
Quinolones/Fluoroquinolones; enrofloxacin, ciprofloxacin
Aminoglycoside; gentamicin Tetracycline
Polymyxins; Colistin Sulphate
|T, P, GP
T, P, GP
T, P, GP
T, P, GP
K. pneumoniae and ESBL-producing K. pneumoniae
|Septicemic, Pneumonic, Urinary Tract Infections (UTIs)|| |
|Aminoglycoside; Amikacin, Gentamicin, Tobramycin
β-lactams; Cefoperazone, Cephalothin, Cefoxitin, Piperacillin, Cefotaxime, Ampicillin-sulbactam, Imipenem, Ticarcillin, Mezlocillin, Carbapenems
Tetracycline; Doxycycline, Minocycline
Quinolones/Fluoroquinolones; Ciprofloxacin, Levofloxacin
|T, P T, P, GP T, P, GP T, P||Acinetobacter baumanii||Skin and soft tissue infections, Ventilator-associated pneumonia, Bacteraemia||  |
|β-lactams; Cefazolin, Ampicillin, Cephalothin
Lincosamides; Clindamycin, Lincomycin
|T, P, GP
T, P, GP
|Pseudomonas aeruginosa||Pneumonia, Septicaemia, Osteomyelitis|||
|Azoles; Itraconazole, Fluconazole||T, P||Candida spp.
C. albicans, C. tropicalis, C. krusei, C. parapsilosis sensu lato,
|Candidiasis||  |
|Azoles; Fluconazole||T, P||Cryptococcus spp. Cryptococcus neoformans||Cryptococcosis|||
Table 2: Summarising incidents of zoonotic disease from veterinary AMR bacterial and fungal species; T – Therapeutic, P – disease prevention (prophylactic/metaphylactic), GP – growth promotion.
Influence on Morbidity
The presence of antibiotic drug residues in food products coming from agriculture and aquaculture poses a threat to public health safety as such contamination is typically unrecognised. Additionally, the contamination of water supplies from agricultural runoff and waste water adds to the concentration of drug available for human consumption. Fat soluble antibiotics such as tetracycline and sulphonamides may also bio-accumulate in animal tissue where they then become a food pollutant . There is little information available on the effect of these compounds, the rate of bioaccumulation and incidence of morbidity in humans and animals. The presence of antibiotic contamination in dairy products and their role in triggering allergic reactions is one such possibility . Penicillin is an antibiotic with little toxicity except for cases of allergic reactions where anaphylactic shock is high risk. The presence of penicillin in dairy products is therefore of concern for persons presenting with allergies towards this drug. Additionally, antibiotics are known to have adverse effects on both the liver and kidneys however; little information is available on their effects on mammalian cells and human toxicity . Injury to the liver caused by antibiotics manifests as hepatitis caused by isoniazid and sulphonamides, cholestasis from macrolides and penicillin’s and steatosis caused by tetracycline. Potentially, toxic effects could be found in treated animals, animals exposed to environmental contamination and incidental uptake and humans exposed from food contamination or zoonotic transmission. Dysbiosis an imbalance of the microbiota of the gastrointestinal tract (GIT) in animal and humans following consumption of antibiotics is also a possibility. This imbalance in gut microbiota leaves the patient susceptible to gastrointestinal infections; antibiotic associated diarrhoea (AAD) and can lead to colitis of the GIT. Microbial species associated with such dysbiosis and antibiotic depletion of the gut microbiome include Klebsiella pneumoniae, Staphylococcus aureus and Clostridium difficile . C. difficile infection often results in patient mortality and is frequently associated with the use of clindamycin, cephalosporin or fluoroquinolones, and the microbiota of patients with C. difficile infection has a diminished natural diversity . Immunocompromised persons and neonates are particularly at risk from AMR and untreatable infections. Colonisation of the GIT by vancomycinresistant Enterococcus has been shown to precede bloodstream infection in immunocompromised patients, where experimental work in mice established that antibiotic treatment plays a role in the intestinal outgrowth of this bacterium . Additionally, an alteration in the gut microbiome can have a negative effect on the immune system of the host. Commensal gut microbes are in close contact to intestinal epithelial cells where a barrier prevents commensal and pathogenic microorganisms entering into the gut lumen. These epithelial cells and paneth cells also secrete antimicrobial peptides (AMPs)  which play an important role in immunity. Depletion of the gut microbiota and an over growth of a non-commensal AMR strains can have a deleterious impact on this function. Epidemiological studies have shown a correlation between the use of antibiotics and childhood obesity which is also accompanied by an increased risk of metabolic and cardiovascular disease, musculoskeletal problems as well as psychosocial issues . Studies report that the administering of antibiotics to children in infancy [64,65] is related to a higher body mass index (BMI) and an increased risk of obesity  throughout childhood.
The over use and misuse of antibiotics over the last number of decades has generated a serious problem with no immediate solution in sight. Human infection with antibiotic resistant bacterial species has increased patient morbidity and mortality rates globally. The presence of these drug compounds in waterways and foods has resulted in both water and food contamination at levels currently unknown. It is of the upmost importance to determine the effect of such contamination on human morbidity and public health safety. Measures must also be taken to slow the rate of emergence in currently treatable bacterial species. The use of antibiotics for the treatment of conditions, which are not of bacterial origin or in cases where there is little or no evidence of efficacy has greatly proliferated AMR. In order to control the increasing rate of bacterial species gaining resistance, measures must be taken to limit the use antibiotics as both human and veterinary therapeutics. This is important not only from an AMR perspective but also to ensure public health safety where there is increasing evidence linking antibiotics to human morbidity especially in infants. Several studies have shown that the zoonotic transmission of infectious pathogenic microbial species is a serious cause of human disease. Furthermore, the impact of bacterial resistance and the increasing loss of antibiotic effectiveness is a significant challenge for both animal health and public health safety. With the aim of reducing AMR the EU implemented a ban in 2006 on the use of antibiotic growth promoters; this was not implemented however, by other countries such as China and the USA.
Conflicts of Interests
The authors declare no conflict of interest.
- Le Page G, Gunnarsson L, Snape J, et al. Integrating human and environmental health in antibiotic risk assessment: A critical analysis of protection goals, species sensitivity and antimicrobial resistance. Environment International 2017.
- Martinez JL. Environmental pollution by antibiotics and by antibiotic resistance determinants. Environmental Pollution 2009;157:2893-2902.
- MacGowan A, Macnaughton E. Antibiotic resistance, Medicine. J mpmed 2017;7:006.
- Done YH, Venkatesan KA, Halden RU. Does the Recent Growth of Aquaculture Create Antibiotic Resistance Threats. Different from those Associated with Land Animal Production in Agriculture? The AAPS Journal 2015;17.
- Karam G, Chastre J, Wilcox MH, Vincent JL. Antibiotic strategies in the era of multidrug resistance. Critical Care 2016;20:136.
- Economou V, Gousia P. Agriculture and food animals as a source of antimicrobial-resistant bacteria. Infection and drug resistance 2015;8.
- Kumar S, Singh B. An Overview of Mechanisms and Emergence of Antimicrobials Drug Resistance 2013;1:7-14.
- Li XZ, Mehrotra M, Ghimire S, et al. β-Lactam resistance and β-lactamases in bacteria of animal origin. Veterinary microbiology 2007;121:197-214.
- Poirel L, Jayol A, Nordmann P. Polymyxins: antibacterial activity, susceptibility testing, and resistance mechanisms encoded by plasmids or chromosomes. Clinical Microbiology Reviews 2017;30:557-96.
- Olaitan AO, Morand S, Rolain JM. Mechanisms of polymyxin resistance: acquired and intrinsic resistance in bacteria. Frontiers in microbiology 2014;5.
- Kong LCG, Wang Z, Gao YH, et al. Antimicrobial susceptibility and molecular characterization of macrolide resistance of Mycoplasma bovis isolates from multiple provinces in China. Journal of Veterinary Medical Science 2016;78:293-6.
- Pyörälä S, Baptiste KE, Catry B, et al. Macrolides and lincosamides in cattle and pigs: Use and development of antimicrobial resistance. The Veterinary Journal 2014;200:230-9.
- Wang Z, Kong LC, Jia BY, et al. Aminoglycoside susceptibility of Pasteurella multocida isolates from bovine respiratory infections in China and mutations in ribosomal protein S5 associated with high-level induced spectinomycin resistance. The Journal of Veterinary Medical Science 2017;7:79.
- Müller S, Janssen T, Wieler LH. Multidrug resistant Acinetobacter baumannii in veterinary medicine–emergence of an underestimated pathogen? Berliner und Munchener tierarztliche Wochenschrift 2014;127:435-46.
- Endimiani A, Hujer KM, Hujer AM, et al. Acinetobacter baumannii isolates from pets and horses in Switzerland: molecular characterization and clinical data. Journal of Antimicrobial Chemotherapy 2011;66:2248-54.
- Day M, Doumith M, Jenkins C, et al. Antimicrobial resistance in Shiga toxin-producing Escherichia coli serogroups O157 and O26 isolated from human cases of diarrhoeal disease in England, 2015. Journal of Antimicrobial Chemotherapy 2017;72:145-52.
- Schwarz S, Kehrenberg C, Doublet B, et al. Molecular basis of bacterial resistance to chloramphenicol and florfenicol. FEMS microbiology reviews 2014;28:519-42.
- Zhang X, Li Y, Liu B, et al. Prevalence of veterinary antibiotics and antibiotic-resistant Escherichia coli in the surface water of a livestock production region in northern China. PLOS ONE 2014;9:e111026.
- Chang SK, Lo DY, Wei HW, et al. Antimicrobial resistance of Escherichia coli isolates from canine urinary tract infections. Journal of Veterinary Medical Science 2015;77:59-65.
- Wang Y, Lv Y, Cai J, et al. A novel gene, optrA that confers transferable resistance to oxazolidinones and phenicols and its presence in Enterococcus faecalis and Enterococcus faecium of human and animal origin. Journal of Antimicrobial Chemotherapy 2015;70:2182-90.
- Marosevic D, Kaevska M, Jaglic Z. Resistance to the tetracyclines and macrolide-lincosamide-streptogramin group of antibiotics and its genetic linkage–a review. Ann Agric Environ Med 2017;24:338-44.
- Nhung NT, Chansiripornchai N, Carrique-Mas JJ. Antimicrobial Resistance in Bacterial Poultry Pathogens: A Review. Frontiers in Veterinary Science 2017;4:126.
- Shin SW, Shin MK, Jung M, et al. Prevalence of Antimicrobial Resistance and Transfer of Tetracycline Resistance Genes in Escherichia coli Isolated from Beef Cattle. Applied and environmental microbiology 2015;pp:1511-15.
- Hao H, Sander P, Iqbal Z, et al. The Risk of Some Veterinary Antimicrobial Agents on Public Health Associated with Antimicrobial Resistance and their Molecular Basis. Frontiers in Microbiology 2016;7:1626.
- Vingopoulou EI, Delis GA, Batzias GC, et al. Prevalence and mechanisms of resistance to fluoroquinolones in Pseudomonas aeruginosa and Escherichia coli isolates recovered from dogs suffering from otitis in Greece. Veterinary Microbiology 2018;213:102-7.
- Redgrave LS, Sutton SB, Webber MA, et al. Fluoroquinolone resistance: mechanisms, impact on bacteria, and role in evolutionary success. Trends in Microbiology 2014;22:438-45.
- Pallo-Zimmerman LM, Byron JK, Graves TK. Fluoroquinolones: then and now. Compendium: Continuin Education for Veterinarians 2010;9.
- Hollis A, Ahmed Z. The path of least resistance: Paying for antibiotics in non-human uses. Health Policy 2014;118:264-70.
- Tasho PR, Cho JY. Veterinary antibiotics in animal waste, its distribution in soil and uptake by plants: A review. Science of the Total Environment 2016;pp:366-376.
- Jechalke S, Heuer H, Siemens J, et al. Fate and effects of veterinary antibiotics in soil. Trends in Microbiology 2014;22.
- Pikkemaat MG. Microbial screening methods for detection of antibiotic residues in slaughter animals. Analytical and Bioanalytical Chemistry 2013;395:893-905.
- McKellar QA. Antimicrobial resistance: a veterinary perspective. Antimicrobials are important for animal welfare but need to be used prudently. BMJ 1998;317:610-11.
- Theuretzbacher U. Antibiotic innovation for future public health needs. Clinical Microbiology and Infection 2017;23:713-7.
- Xiong M, Wu X, Ye X, et al. Relationship between Cefquinome PK/PD Parameters and Emergence of Resistance of Staphylococcus aureus in Rabbit Tissue-Cage Infection Model. Frontiers in Microbiology 2016.
- Cavaco LM, Abatih E, Aarestrup FM, et al. Selection and Persistence of CTX-M-Producing Escherichia coli in the Intestinal Flora of Pigs Treated with Amoxicillin, Ceftiofur, or Cefquinome. Antimicrobial agents and chemotherapy 2008;52:3612-6.
- Rhouma M, Beaudry F, Letellier A. Resistance to colistin: what is the fate for this antibiotic in pig production? International Journal of Antimicrobial Agents 2016;48:119-26.
- Chang SK, Lo DY, Wei HW, et al. Antimicrobial resistance of Escherichia coli isolates from canine urinary tract infections. Journal of Veterinary Medical Science 2016;77:59-65.
- Grenni P, Ancona V, Caracciolo AB. Ecological effects of antibiotics on natural ecosystems: A review. Microchemical Journal 2018;136:25-39.
- Yezli S, Li H. Antibiotic resistance amongst healthcare-associated pathogens in China. International Journal of Antimicrobial Agents 2012;40:389-97.
- Rodriquez-Rojas A, Rodriquez-Beltran J, Couce A, et al. Antibiotics and antibiotic resistance: A bitter fight against evolution. International Journal of Medical Microbiology 2013;303:293-7.
- Anes, McCusker MP, Fanning S, et al. The ins and outs of RND efflux pumps in Escherichia coli. Frontiers in Microbiology 2015;pp:00587.
- Ratova M, Mills A. Antibacterial titania-based photocatalytic extruded plastic films. Journal of Photochemistry and Photobiology A: Chemistry 2015;299:159-65.
- Karikari AB, Obiri-Danso K, Frimpong EH, et al. Multidrug resistant Campylobacter in faecal and carcasses of commercially produced poultry. African Journal of Microbiology Research 2017;11:271-7.
- Iovine NM. Resistance mechanisms in Campylobacter jejuni. Virulence 2013;4:230-40.
- Thibodeau A, Fravalo P, Laurent-Lewandowski S, et al. Presence and characterization of Campylobacter jejuni in organically raised chickens in Quebec. Canadian Journal of Veterinary Research 2011;75:298-307.
- Luangtongkum T, Jeon B, Han J, et al. Antibiotic resistance in Campylobacter: emergence, transmission and persistence. Future Microbiology 2009;4:189-200.
- Nobili G, Franconieri I, La Bella G, et al. Prevalence of Verocytotoxigenic Escherichia coli strains isolated from raw beef in southern Italy. International Journal of Food Microbiology 2017;257:201-5.
- Sharaf EF, Shabana II. Prevalence and molecular characterization of Shiga toxin-producing Escherichia coli isolates from human and sheep in Al-Madinah Al-Munawarah. Infection 2016.
- Osman KM, Hassan HM, Orabi A, et al. Phenotypic, antimicrobial susceptibility profile and virulence factors of Klebsiella pneumoniae isolated from buffalo and cow mastitic milk. Pathogens and Global Health 2014;108:191-9.
- Liu D, Liu ZS, Hu P, et al. Characterization of surface antigen protein 1 (SurA1) from Acinetobacter baumannii and its role in virulence and fitness. Veterinary microbiology 2016;186:126-38.
- Merwad A. Occurrence and molecular characterization of multidrug-resistant Acinetobacter baumannii isolated from humans and dogs 2016;64:S1-S7.
- Bernal-Rosas Y, Osorio-Munoz K, Torres-García O. Pseudomonas aeruginosa: An emerging nosocomial trouble in veterinary 2015;20:4937-46.
- Rocha MFG, Bandeira SP, Alencar LP, et al. Azole resistance in Candida albicans from animals: Highlights on efflux pump activity and gene overexpression. Mycoses 2017.
- Cordeiro Rd A, Oliveira JSd, Castelo-Branco Dd SCM, et al. Candida tropicalis isolates obtained from veterinary sources show resistance to azoles and produce virulence factors. Sabouraudia 2014;53:145-52.
- Brilhante RSN, de Alencar LP, de Aguiar Cordeiro R, et al. Detection of Candida species resistant to azoles in the microbiota of rheas (Rhea americana): possible implications for human and animal health. Journal of medical microbiology 2013;62:889-95.
- Kano R, Okubo M, Yanai T, et al. First isolation of azole-resistant Cryptococcus neoformans from feline Cryptococcosis. Mycopathologia 2015;180:427-33.
- Metsälä J, Lundqvist A, Virta LJ, et al. Mother's and offspring's use of antibiotics and infant allergy to cow's milk. Epidemiology 2013;24:303-9.
- Dai J, Hamon M, Jambovane S. Microfluidics for Antibiotic Susceptibility and Toxicity Testing. Bioengineering 2016;3:25.
- Westphal JF, Vetter D, Brogard JM. Hepatic side-effects of antibiotics Journal of Antimicrobial Chemotherapy 1994;33:387-401.
- Francino PM. Antibiotics and the Human Gut Microbiome: Dysbioses and Accumulation of Resistances. Frontiers in Microbiology 2016.
- Ubeda C, Pamer EG. Antibiotics, microbiota, and immune defense. Trends in Immunology 2012;33:459-66.
- Ubeda C, Taur Y, Jenq RR, et al. Vancomycin-resistant Enterococcus domination of intestinal microbiota is enabled by antibiotic treatment in mice and precedes bloodstream invasion in humans. Journal of Clinical Investigation 2010;120:4332-41.
- Turta O, Rautava S. Antibiotics, obesity and the link to microbes - what are we doing to our children? BMC Medicine 2016;14:57.
- Saari A, Virta LJ, Sankilampi U, et al. Antibiotic exposure in infancy and risk of being overweight in the first 24 months of life. Pediatrics 2015;135:617-32.
- Azad MB, Bridgman SL, Becker AB, et al. Infant antibiotic exposure and the development of childhood overweight and central adiposity. International Journal of Obesity 2014;38:1290-8.