Carbapenem resistance due to BlaOXA-48 Clone ST38 among ESBL-producing Escherichia coli isolates from patients hospitalised at the university hospital of Constantine in Algeria.

The aim of this study was to investigate the prevalence and to assess the frequency and diversity of carbapenemases produced by Escherichia coli isolates in the university hospital of Constantine in Algeria. A total of 235 strains of Escherichia coli were isolated from patients from February 2014 until June 2015 and identified with biochemical approaches and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). Antimicrobial susceptibility was determined using the disk diffusion and E-test methods. Carbapenemase activity was studied using modified Hodge test, modified Carba NP test, and EDTA test. Carbapenem resistance determinants were detected by real-time PCR and standard polymerase chain reaction (PCR) followed by sequencing. The genes coding for the ESBL were determined by PCR and sequencing. Carbapenemase-producing Escherichia coli isolates were typed by MLST and their transferability was studied by a conjugation experiment followed by antibiogram and PCR amplification of the plasmid DNA. As results, two strains of E. Coli were resistant to ertapenem with MIC= 4 mg/l. They presented a resistance to beta-lactams, to aminoglycosides and fluoroquinolones. However, they were susceptible to imipenem and colistin. In addition, they were revealed producing the blatem-1 gene. They were positive with the modified Hodge test and modified Carba NP test. Real-time PCR, standard PCR and sequencing showed the presence of blaoxa-48 gene in these strains. The results of conjugation experiment and the extraction of the plasmid which were negative showed that these resistance genes are chromosomally encoded. MLST with seven housekeeping genes demonstrated that the two strains of E. Coli OXA-48 producers belong to ST38. In conclusion, here, we demonstrate the emergence and dissemination of carbapenemase-producing E. Coli strains at the university hospital of Constantine in Algeria and we report the first blaoxa-48 ST38 producing E. Coli clinical isolates from patients in Algeria.