Comparative Phenotypic Analysis of Multidrug Resistance and Associated Risk Factors in Avian Pathogenic and Fecal Escherichia coli from Central Algerian Poultry Systems

The emergence of antibiotic resistance in poultry farming threatens animal health, food safety, and public health. This study characterized and compared AMR profiles between avian pathogenic and fecal Escherichia coli (APEC and AFEC) and identified key risk factors associated with multidrug resistance (MDR, defined as resistance to at least three antibiotic classes). Two hundred Escherichia coli (100 APEC, 100 AFEC) were identified from 360 clinical and fecal samples collected in central Algeria, yielding prevalences of 46.5% for APEC and 68.97% for AFEC. Antibacterial susceptibility to 24 antibiotics was assessed using the disk diffusion method. Multiple correspondence analysis (MCA) was applied as an exploratory tool to uncover associations between resistance patterns and risk factors. APEC and AFEC strains demonstrated pronounced resistance to the first-line therapeutic antibiotics, notably tetracycline (84%, 91%), ampicillin (82%, 74%), amoxicillin (80%, 71%), and nalidixic acid (76%, 74%), while preserving full susceptibility to carbapenems and cefoxitin. Poultry age was the primary driver of MDR in APEC isolates, whereas MDR in AFEC was primarily linked to inadequate ventilation and suboptimal humidity levels. Fisher’s exact test indicated no significant differences in susceptibility rates between APEC and AFEC isolates (p>0.05), except for tobramycin. This first comprehensive AMR assessment in Algerian poultry emphasizes the multifactorial nature of its emergence, the imperative need for improved antimicrobial stewardship and farm management policies to safeguard animal and public health.