Extended Spectrum β-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae from Broiler Liver in the Center of Algeria, with Detection of CTX-M-55 and B2/ST131-CTX-M-15 in Escherichia coli.

This study aimed to determine the prevalence and diversity of extended-spectrum β-lactamase (ESBL)-producing and multidrug-resistant (MDR) Escherichia coli and Klebsiella pneumoniae isolates from 136 broiler livers randomly purchased in 136 retail markets in Djelfa (Algeria). Isolation was performed on Hektoen agar and bacterial identification was carried out by API20E system and Maldi-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry). Antimicrobial susceptibility was tested by the disk diffusion and agar dilution methods. Detection of ESBLs and other resistance and integron genes, phylogenetic grouping, and molecular typing was performed by PCR and sequencing. Seventy-eight isolates (one per positive sample) were recovered: 73 E. coli and 5 K. pneumoniae. Among E. coli, 86.3% of isolates were MDR. ESBL activity was revealed in eight E. coli and five K. pneumoniae isolates (rates of 5.9% and 3.7% in analyzed samples, respectively). ESBL genes detected among E. coli were as follows (number of isolates): blaCTX-M-15 (3), blaCTX-M-1 (3), blaCTX-M-55 (1), and blaSHV-12 (1); all ESBL-producing K. pneumoniae isolates carried the blaCTX-M-15 gene. ESBL-producing E. coli isolates were assigned to lineages (phylogroup/sequence type and number of isolates in parenthesis): A/ST48 (1), B1/ST6448 (1), B1/ST5087 (3), B1/ST23 (1), and B2/ST131 (two blaCTX-M-15 E. coli isolates). K. pneumoniae isolates were ascribed to sequence types ST2010 and ST3483. Regarding the 65 non-ESBL E. coli isolates, the most observed resistance genes were as follows: tet(A) (75%), blaTEM (57.1%), and sul2 (43.5%). Class1 integrons were revealed in seven non-ESBL E. coli isolates (10.7%) and two gene-cassette arrays were identified: dfrA1 and aadA1+dfrA1. Our study provides evidence that broiler-derived food from Center of Algeria constitutes a source of ESBL and/or MDR-producing Enterobacteriaceae, with detection of relevant ESBL genes and epidemic clones.