Increased raw poultry meat colonization by extended spectrum beta-lactamase-producing Escherichia coli in the south of Spain

The present study was conducted to assess the prevalence of retail chicken and turkey meat colonized by extended-spectrum beta-lactamase-producing Escherichia coli (ESBLEC) in Seville, Spain. ESBLEC recovered from meat samples purchased in 2010 were characterized by specific PCR analysis for bla genes, phylogenetic groups and subgroups (genotypes) and O25b/pabB/B2 traits of ST131. Results were compared with those obtained in a previous study in 2007, when a high percentage of retail meat samples were found to be colonized by ESBLEC. The prevalence of retail poultry meat colonized by ESBLEC increased from 62.5% in 2007 to 93.3% in 2010 (p=0.005). Non-pathogenic B1 and A1 genotypes accounted for more than 60% of the 60 isolates recovered. Sequence type ST131 or B2 phylogroup isolates were not detected. Clonal relatedness was detected in just 2 CTX-M-1-producing isolates from 2 chicken samples belonging to phylogenetic group A, genotype A1. There continued to be a significantly high quinolone resistance, with 85.4% and 32.2% of isolates showing resistance to nalidixic acid and ciprofloxacin, respectively. SHV-12 was the most common ESBL harbored by E. coli, although it has decreased in prevalence since 2007. Meanwhile, CTX-M ESBLs prevalence has increased. We conclude that the trend of colonization by ESBLECs—particularly CTX-M-producing isolates—in raw poultry meat has increased in a short period of time in our area.