Occurrence of tetracycline residues and antimicrobial resistance in gram negative bacteria isolates from cattle farms in Spain

Abstract

The usage of antibiotics in animal husbandry has dramatically increased the concentration of antibiotic residues and has promoted the development and abundance of antibiotic resistance in manure. When it is spread onto agricultural land, both residues of antibiotics and bacteria carrying antibiotic resistance genes may be introduced into the environment. In this research, we isolated resistant gram negative bacteria from manure produced in two dairy and two beef cattle farms, located in Madrid (Spain), to determine their resistance to seventeen representative antibiotics commonly used in veterinary therapy. A total of 63 isolates were used to assess the overall bacterial antimicrobial resistance on cattle manure samples. Predominant species were Escherichia coli and Comamonas testosteroni accounting for 25% and 19.6% of the total, respectively. The most found antimicrobial resistances in gram-negative bacteria were to tetracycline (66.7%), sulphamethoxazole (55.6%), ampicillin (52.4%), cephalothin (46.0%), chloramphenicol (44.4%), nalidixic acid (39.7%) and trimethroprimsulphamethoxazole (33.3%). The mean of resistance and the percentage of multi-resistant bacteria in beef farms were higher and statistically significant when compared to dairy farms which is opposite from the findings of the previous studies. The presence of three tetracyclines in all manure samples was also examined with stable recoveries (76% -82%) and high sensitivity (limit of quantification 0.015 -0.03 μg/kg). The concentrations of tetracyclines detected (<0.015 -10 mg/kg) were consistent to the theoretical tetracycline levels in manure in Spain according to the excretion rate of these antibiotics and the values reported in scientific literature in other European countries.

Tetracyclines in Food and Feedingstuffs: From Regulation to Analytical Methods, Bacterial Resistance, and Environmental and Health Implications

“…Nonetheless, some unmedicated feed for fish, swine, and poultry contained considerable populations of OTC-resistant bacteria, suggesting that raw materials and manufacturing processes may also impact the carriage of OTC-resistant bacteria in animal feed [ 145 ]. Carballo et al [ 146 ] recovered a total of 63 isolates from manure samples collected from Spanish cattle farms; in this study Escherichia coli and Comamonas testosteroni accounted for 25% and 19.6% of the species recovered, respectively. The most common antimicrobial resistance documented in Gram-negative bacteria was toward tetracycline (67%).…”

Antibiotic Use in Agriculture and Its Consequential Resistance in Environmental Sources: Potential Public Health Implications

“…Rasheed et al [ 105 ] equally noted an overall incidence of 14.7% of drug-resistant E. coli obtained from vegetable salad, unpasteurized milk, raw chicken, raw meat, and raw egg surface, with 4% of these isolates exhibiting the extended-spectrum β-lactamase activity. In addition, Carballo et al [ 106 ] recovered three tetracycline residues and sixty-three antibiotic-resistant Gram-negative bacteria that presented with percentage resistance between 33.3% and 66.7% to five well-known antibiotics employed in livestock farming, viz. tetracycline, chloramphenicol, nalidixic acid, sulphamethoxazole, and ampicillin.…”

Prevalence of Antibiotic-Resistant Bacteria in the Environment of Poultry Farms

“…Carballo et al observed between 33.3% and 66.7% resistance to ve well-known antibiotics used in livestock farming, viz. tetracycline, chloramphenicol, nalidixic acid, sulfamethoxazole and ampicillin [17].…”