Prospective, multicenter observational study to collect Escherichia coli (E. coli) isolates originating from mechanically ventilated intensive care unit (ICU) patients; in order to characterize phenotype and genotype of E. coli strains retrieved from the lower respiratory tract of ventilated patients.
Prospective, observational, multiple center study performed in 14 ICUs in France to collect Escherichia coli (E. coli) isolates originating from mechanically ventilated intensive care unit (ICU) patients; in order to characterize phenotype and genotype of E. coli strains retrieved from the lower respiratory tract of ventilated patients. All E. coli isolates identified in the microbiology lab and retrieved from a lung specimen (either tracheal aspirate, bronchoalveolar lavage, or telescopic plugged catheter) originating from an ICU patient will be kept, and stored at -80°C in brain-heart infusion broth containing glycerol 20 %. They will be then centralized in the investigators' research unit for further analysis that includes determination of Antimicrobial susceptibility, E. coli phylotype , O-type, and virulence factor gene content. These isolates will be compared to those of two previously published collections, one from the stools of community subjects, considered as commensal strains, the other from the blood of bacteraemia patients.
Study Type
OBSERVATIONAL
Enrollment
289
phylogenetic group determination
Quadruplex polymerase chain reaction (PCR) method was used to determine the E. coli phylogenetic group (A, B1, B2, C, D, E, F), or Escherichia clade I belonging
Time frame: 50 minutes
O-type determination
polymerase chain reaction (PCR) method was used to search for the most anticipated serotypes in extra-intestinal infections : O1, O2a, O2b, O4, O6, O7, O12, O15, O16, O17, O18, O22, O25a, O25b, O45a, O75, O78
Time frame: 50 minutes
virulence factor (VF) gene content determination
Multiplex PCR was used to detect genes encoding for eleven frequently encountered extraintestinal VFs (S and F fimbriae (sfa/foc), pili associated with pyelonephritis (papC), P adhesin (papGII, papGIII), the ferric yersiniabactin uptake receptor (fyuA), iron transport (iroN), aerobactin (aer), conjugal transfer protein (traT), N-acetylglucosamine 2-epimerase protein (neuC), hemolysin (hlyC), and the cytotoxic necrotizing factor 1(cnf1)
Time frame: 90 minutes
antimicrobial susceptibility determination
Antimicrobial susceptibility of each isolate was determined by disk-diffusion method according to the French Society of Microbiology. Resistance score was defined as the sum of inactive in vitro antimicrobial agents for each isolate
Time frame: 24 hours
presence of betalactamase
Detection of gene sequences coding for the CTX-M and TEM enzymes was performed by PCR with genomic DNA
Time frame: 90 minutes
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