10
Escherichia coli, Campylobacter jejuni, etc., which can cause infection in humans
(Phillips et al. 2004). Many of these pathogens also indicate fecal contamination in
water or soil, and are used as a measure of suitability for human consumption. This
is important because these pathogens also have high recombination frequency and
propensity towards exchange of antibiotic resistance genes through horizontal gene
transfer. The phylogenetic relatedness of these bacteria further facilitates the transfer and exchange of antibiotic resistance genes among themselves. These situations
potentiate the development of antibiotic resistance even more rapidly among the
microbes sharing the same niche. The public health risks arising from these antibiotic resistant microbes cannot be easily estimated owing to their complex distribution pattern among food animals and humans. There is lack of fast and reliable
detection techniques for manifestation of antibiotic resistance, complex pattern of
exchange of antibiotic resistance genes, unreliable prediction tools to understand
implications in mortality and morbidity of humans and fluctuating treatment cost
associated with infections caused by such pathogens (Wegener 2012). Essentially,
these antibiotic resistant zoonotic pathogens can act as vectors for antibiotic resistance in humans. Thus, antibiotic resistance in the pathogens common to both animals and humans is worrisome and certainly indicates origin of many antibiotic
resistant pathogens from animal farms or related activities.
Most of the veterinary use antibiotics have structural similarity with human use
antibiotics and it could directly drive microbes inside humans towards resistance.
Another hazard of antibiotic usage in animals is the accumulation of antibiotic residues in tissues and edible organs of animals in varying concentrations. Some reports
have shown the direct presence of tetracycline and chloramphenicol residues
(Cameroon, Iran, Egypt) above its maximum residue limit (European Union standards) in muscle, heart, liver and kidney of farm chicken (Tavakoli et al. 2015;
Guetiya Wadoum et al. 2016). Similar reports for presence of different antibiotics
have been reported such as ciprofloxacin has been found inside eggs of terminally
ill birds receiving antibiotic treatment (Billah et al. 2015), quinolones inside Chicken
and Beef (Er et al. 2013) in Turkey, amoxicillin in milk and eggs in Bangladesh
(Chowdhury et al. 2015), sulfonamides and quinolones in milk in China, Malaysia
and India (Cheong et al. 2010; Zheng et al. 2013; Nirala et al. 2017). Exposure to
antibiotics from animal derived food can create multiple complications in humans,
such as neuropathy, drug hypersensitivity, aplastic anemia, mutagenesis, disturbance of normal gut flora, hepatotoxicity, reproductive disorder and of course development of antibiotic resistance in the gut colonizing bacteria (Lee et al. 2001; Nisha
2008; Beyene 2015). These manifestations in humans can be a result of exposures
both acute or of long periods through the food. Ideally speaking, no antibiotics or its
residues should be present in the food directly or indirectly derived from animals.
However for practical reasons, it is difficult to handle and to ascertain the safe
antibiotic levels in animal derived food and a maximum residue limit for antibiotics
in animal derived food has been recommended by European Union and other
authorities (Alimentarius 2012). The level of antibiotics excreted by animals differs
dramatically depending upon the metabolization of the antibiotic, age, diet and
K. S. Singh et al.
Escherichia coli, Campylobacter jejuni, etc., which can cause infection in humans
(Phillips et al. 2004). Many of these pathogens also indicate fecal contamination in
water or soil, and are used as a measure of suitability for human consumption. This
is important because these pathogens also have high recombination frequency and
propensity towards exchange of antibiotic resistance genes through horizontal gene
transfer. The phylogenetic relatedness of these bacteria further facilitates the transfer and exchange of antibiotic resistance genes among themselves. These situations
potentiate the development of antibiotic resistance even more rapidly among the
microbes sharing the same niche. The public health risks arising from these antibiotic resistant microbes cannot be easily estimated owing to their complex distribution pattern among food animals and humans. There is lack of fast and reliable
detection techniques for manifestation of antibiotic resistance, complex pattern of
exchange of antibiotic resistance genes, unreliable prediction tools to understand
implications in mortality and morbidity of humans and fluctuating treatment cost
associated with infections caused by such pathogens (Wegener 2012). Essentially,
these antibiotic resistant zoonotic pathogens can act as vectors for antibiotic resistance in humans. Thus, antibiotic resistance in the pathogens common to both animals and humans is worrisome and certainly indicates origin of many antibiotic
resistant pathogens from animal farms or related activities.
Most of the veterinary use antibiotics have structural similarity with human use
antibiotics and it could directly drive microbes inside humans towards resistance.
Another hazard of antibiotic usage in animals is the accumulation of antibiotic residues in tissues and edible organs of animals in varying concentrations. Some reports
have shown the direct presence of tetracycline and chloramphenicol residues
(Cameroon, Iran, Egypt) above its maximum residue limit (European Union standards) in muscle, heart, liver and kidney of farm chicken (Tavakoli et al. 2015;
Guetiya Wadoum et al. 2016). Similar reports for presence of different antibiotics
have been reported such as ciprofloxacin has been found inside eggs of terminally
ill birds receiving antibiotic treatment (Billah et al. 2015), quinolones inside Chicken
and Beef (Er et al. 2013) in Turkey, amoxicillin in milk and eggs in Bangladesh
(Chowdhury et al. 2015), sulfonamides and quinolones in milk in China, Malaysia
and India (Cheong et al. 2010; Zheng et al. 2013; Nirala et al. 2017). Exposure to
antibiotics from animal derived food can create multiple complications in humans,
such as neuropathy, drug hypersensitivity, aplastic anemia, mutagenesis, disturbance of normal gut flora, hepatotoxicity, reproductive disorder and of course development of antibiotic resistance in the gut colonizing bacteria (Lee et al. 2001; Nisha
2008; Beyene 2015). These manifestations in humans can be a result of exposures
both acute or of long periods through the food. Ideally speaking, no antibiotics or its
residues should be present in the food directly or indirectly derived from animals.
However for practical reasons, it is difficult to handle and to ascertain the safe
antibiotic levels in animal derived food and a maximum residue limit for antibiotics
in animal derived food has been recommended by European Union and other
authorities (Alimentarius 2012). The level of antibiotics excreted by animals differs
dramatically depending upon the metabolization of the antibiotic, age, diet and
K. S. Singh et al.