Multidrug-Resistant and Potentially Pathogenic Escherichia coli Prevalent in Samples of Different Types of Raw Meat Sold in Informal Markets in Luanda, Angola

Raw meat can act as a reservoir and vehicle for antimicrobial-resistant foodborne Escherichia coli, particularly when sold under poor hygienic conditions, as is often the case in informal markets in many developing countries, thereby representing a significant public health risk. This study aimed to characterize the antibiotic resistance patterns and virulence of E. coli isolated from raw meat sold in informal markets in Luanda, Angola. A total of 99 E. coli isolates were recovered from fresh beef, pork and goat meat in five informal markets. DNA macrorestriction analysis by Pulsed-Field Gel Electrophoresis (PFGE) was used to evaluate the genetic diversity of isolates. Multiplex PCR was performed to detect virulent and antibiotic resistance genes. Antibiotic susceptibility was tested using the disk diffusion method. PFGE analysis showed high genotypic diversity. Virulence genes were found in 46% of the isolates, with astA (32.3%) being the most frequent. The results also showed high resistance to cefotaxime (67.7%), ampicillin (56.7%) and amoxicillin/clavulanic acid (56.6%). Resistance to imipenem, a last-resort antibiotic, was observed in 30.3% of the isolates. The most prevalent resistance genes were CTX-M group 1 (10.1%) and FOX variants (27.3%). The presence of multidrug-resistant and potentially pathogenic E. coli strains in raw meat sold in informal markets in Luanda represents a significant threat to public health. These findings underscore the urgent need to improve surveillance, hygiene practices, and antimicrobial use regulation policies in animal production in Angola.