Current status of β-lactam antibiotic use and characterization of β-lactam-resistant Escherichia coli from commercial farms by integrated broiler chicken operations in Korea
Hye-Ri Jung, Yu Jin Lee, Yu Jin Lee, Serim Hong, Sunghyun Yoon, Suk‐Kyung Lim, Young Ju Lee, Young Ju Lee
Abstract
β-lactam antibiotics are one of the most clinical importance in human and veterinary medicine because they are used for both preventive and therapeutic purposes against several gram-positive, gram-negative, and anaerobic organisms. In this study, it was confirmed that β-lactams (81.1%) were found to be significantly prescribed the most among 74 farms in five integrated broiler operations, and single prescription (84.6%), two-day (41.5%) or three-day (40.0%) administration and 15–22 days of age (67.7%) administration was significantly higher in the farms (p < 0.05). Among the E. coli isolated from 74 farms in five integrated broiler operations, β-lactam-resistant E. coli isolates were detected more frequently in fecal sample (94.6%) than in dust sample (60.8%) (p < 0.05). The prevalence of MDR in β-lactam-resistant isolates, ranging from 88.1% to 96.5%, was significantly higher than that in non-β-lactam-resistant isolates (p < 0.05), without significant differences among operations. Of 466 β-lactam-resistant isolates, 432 (92.7%) isolates harbored β-lactamase genes. The non-extended-spectrum β-lactamase (ESBL) gene blaTEM-1 (81.8%) showed the highest prevalence among isolates, followed by the non-ESBL gene blaTEM-135 (6.4%) (p < 0.05). Five ESBL genes, SHV-12, OXA-1, CTX-M-27, CTX-M-55 and CTX-M-65, were found in 0.9%–6.0% of the isolates. The pAmpC gene blaCMY-2 was detected in 17 isolates (3.6%). These results suggest that feces and dust are important reservoirs of antimicrobial-resistant bacteria, highlighting the need to strengthen farm management regulations, such as cleaning, disinfection, and litter disposal and to reduce the use of antibiotics in broiler operations.