Antimicrobial Resistance of E. coli Isolated from Broiler Flocks and Slaughterhouses in Batna District, Algeria

In the last few years, the poultry sector in Batna has faced the emergence of atypical diseases. Many professionals suspect unusual viral infections like Newcastle disease, infectious bronchitis, and avian influenza. These diseases are often associated with colibacillosis and salmonellosis, both of which have developed atypical, multi-drug resistance. combat Escherichia (E.) coli superinfections, a study targeted broiler chickens from 80 flocks and two slaughterhouses in the Batna region. Researchers collected organ samples, including neck skin, from both sick animals and those intended for slaughter, isolating 100 E. coli strains—50 from flocks and 50 from slaughterhouses. antibiotic resistance profiles of E. coli isolated from livestock were 62.5% (50/80), revealing moderate resistance rates to several antibiotics. Specifically, resistance was noted for tetracycline (62%), doxycycline (56%), enrofloxacin (44%), ampicillin (46%), amoxicillin (40%), and sulfamethoxazole-trimethoprim (34%). Resistance to colistin showed a lower rate of 20%; amoxicillin-clavulanate and ticarcillin-clavulanate had a resistance of 12% and 8%, respectively. While gentamicin and chloramphenicol had even lower rates at 8% and 6%. Notably, 94% of strains were sensitive to chloramphenicol, and 92% were sensitive to gentamicin. Additionally, 28% of strains were resistant to three antibiotics, and 18% were resistant to four. Escherichia coli isolated from the slaughterhouse was 83.3% (50 / 60) demonstrated higher antibiotic resistance than those from herds. These isolates were resistant to tetracycline, ampicillin, enrofloxacin, and doxycycline, at 82%, 80%, 78%, and 74%, respectively, and had moderate resistance to nalidixic acid, chloramphenicol, sulfamethoxazole-trimethoprim (SXT), and amoxicillin; resistance rates for colistin, gentamicin, and TTC were lower. In terms of multidrug resistance, 42% of the slaughterhouse strains were resistant to five antibiotics, 18% to four, and 14% to two. Nevertheless, these strains remained highly sensitive to colistin and gentamicin.