7
transfer by plasmids (Liu et al. 2016). Usage of colistin and associated antibiotic
resistance is distinct from that of cephalosporins because across many countries, the
consumption of this antibiotic in food animals exceeds multiple times of its consumption in humans (European Center for Disease Prevention and Control 2015).
Many countries and regulatory agencies like European Medicine Agency have recommended drastic reduction in usage of colistin in food animals to save it for usage
in humans.
Similar issues have been faced earlier with glycopeptide antimicrobials which
were also used as growth promoter and not considered relevant drug for humans.
One such example is the glycopeptide ‘avoparcin’, which was extensively used in
food animals (Aarestrup et al. 1996). This led to development of resistance against
glycopeptide class of antibiotics. Now, Vancomycin (also a glycopeptide antibiotic),
which is an important antibiotic against multi drug resistant pathogens (especially
methicillin resistant Staphylococcus aureus) is also facing resistance from many
multi drug resistant pathogens from food, humans and environment (Tang et al.
2014). Unarguably, lessons should be learnt from these previous mistakes related to
rise and spread of certain resistance to classes of antibiotics and caution need to be
exercised in antibiotic usage, to prevent further development of antibiotic resistance
due to metaphylaxis.
1.2.2 Antimicrobial Resistance, Animals and Public Health
The prevailing issue of antibiotic resistance is largely linked with irresponsible
usage of antibiotics and rapid exchange of antibiotic resistance genes among
microbes. The interrelatedness and rapid exchange of antibiotic resistance genes
between pathogens, which can colonize and infect both animals and humans, has
made the problem of antimicrobial resistance even worse (Fig. 1.2). The root cause
of indiscriminate usage arises from the impetus to derive maximum economic benefits from available resources (including livestock) and irresponsible disposal of
generated waste. An example is the usage of broad spectrum antibiotics as growth
promoters, in livestock to increase the amount of meat and overall size. The mechanism behind this is not clear but various hypothesis has been proposed. In one of
them, it has been said that the antibiotics helps in better digestion of food via suppressing the sensitive bacteria of gut that might be resulting in loss of energy due to
bacterial fermentation. In another hypothesis, it has been proposed that the cytokines released during bacterial infection reduces muscle mass and thus the use of
antibiotics helps in overcoming that effect (Hughes et al. 2004). In the countries
such as US, half of the antibiotics given to animals are intended for growth promotion. This practice is often applied on pigs and in major pork producing country
such as China and US. The use of antibiotics in China is four times higher than that
of US in order to increase the pork production (Cully 2014). This is the data which
is being monitored and in comparison of that, there is very little or no information
regarding antibiotics used in small farms. Most of these antibiotics, used in
1 Antimicrobial Resistance Paradigm and One-Health Approach
transfer by plasmids (Liu et al. 2016). Usage of colistin and associated antibiotic
resistance is distinct from that of cephalosporins because across many countries, the
consumption of this antibiotic in food animals exceeds multiple times of its consumption in humans (European Center for Disease Prevention and Control 2015).
Many countries and regulatory agencies like European Medicine Agency have recommended drastic reduction in usage of colistin in food animals to save it for usage
in humans.
Similar issues have been faced earlier with glycopeptide antimicrobials which
were also used as growth promoter and not considered relevant drug for humans.
One such example is the glycopeptide ‘avoparcin’, which was extensively used in
food animals (Aarestrup et al. 1996). This led to development of resistance against
glycopeptide class of antibiotics. Now, Vancomycin (also a glycopeptide antibiotic),
which is an important antibiotic against multi drug resistant pathogens (especially
methicillin resistant Staphylococcus aureus) is also facing resistance from many
multi drug resistant pathogens from food, humans and environment (Tang et al.
2014). Unarguably, lessons should be learnt from these previous mistakes related to
rise and spread of certain resistance to classes of antibiotics and caution need to be
exercised in antibiotic usage, to prevent further development of antibiotic resistance
due to metaphylaxis.
1.2.2 Antimicrobial Resistance, Animals and Public Health
The prevailing issue of antibiotic resistance is largely linked with irresponsible
usage of antibiotics and rapid exchange of antibiotic resistance genes among
microbes. The interrelatedness and rapid exchange of antibiotic resistance genes
between pathogens, which can colonize and infect both animals and humans, has
made the problem of antimicrobial resistance even worse (Fig. 1.2). The root cause
of indiscriminate usage arises from the impetus to derive maximum economic benefits from available resources (including livestock) and irresponsible disposal of
generated waste. An example is the usage of broad spectrum antibiotics as growth
promoters, in livestock to increase the amount of meat and overall size. The mechanism behind this is not clear but various hypothesis has been proposed. In one of
them, it has been said that the antibiotics helps in better digestion of food via suppressing the sensitive bacteria of gut that might be resulting in loss of energy due to
bacterial fermentation. In another hypothesis, it has been proposed that the cytokines released during bacterial infection reduces muscle mass and thus the use of
antibiotics helps in overcoming that effect (Hughes et al. 2004). In the countries
such as US, half of the antibiotics given to animals are intended for growth promotion. This practice is often applied on pigs and in major pork producing country
such as China and US. The use of antibiotics in China is four times higher than that
of US in order to increase the pork production (Cully 2014). This is the data which
is being monitored and in comparison of that, there is very little or no information
regarding antibiotics used in small farms. Most of these antibiotics, used in
1 Antimicrobial Resistance Paradigm and One-Health Approach