Molecular typing and characterization of extended-spectrum TEM, SHV and CTX-M β-lactamases in clinical isolates of Enterobacter cloacae

Sixty-one non-repetitive Enterobacter cloacae ESBL producers were collected at the Amiens University Hospital in France. Eight β-lactam resistance phenotypes (a-h) and three aminoglycoside resistance phenotypes (i-k) were identified among these isolates, and 32 different pulsotypes were observed. Of these 61 isolates, 37 were sequenced and found to harbor β-lactamases with a pI of 5.9 (TEM-4), 6.5 (TEM-24), 7.8 (SHV-4), 8.2 (SHV-12), 8.4 (CTX-M-1) and 8.0 (CTX-M-9). Four imipenem-resistant ESBL-producing E. cloacae isolates did not express the 38 kDa OMP, indicating that this resistance is associated with porin deficiency.