Characterization of novel plasmid-mediated β-lactamases (SHV-167 and ACT-16) associated with New Delhi metallo-β-lactamase-1 harbouring isolates from neonates in India.

Neonatal sepsis due to carbapenem-resistant bacteria is difficult to treat due to limited therapeutic options. The detection of the new carbapenemase New Delhi metallo-β-lactamase-1 (NDM-1) from neonates has further complicated the situation (Roy et al., 2011a). The potent metallo-β-lactamase NDM-1 efficiently hydrolyses all classes of β-lactam antibiotics (penicillins, cephalosporins and carbapenems) and is also associated with multiple determinants that enable the bacteria to become resistant to other antibiotic classes (Nordmann et al., 2011). In the presence of NDM-1 other β-lactamases may go unobserved because of the spectrum of activity of NDM-1 against all β-lactam antibiotics. Thus, under the canopy of the NDM-1 these β-lactamases also get the opportunity to spread. This communication reports association of two novel β-lactamases, SHV-type β-lactamase (SHV-167) and AmpC-type β-lactamase (ACT-16), in two NDM-1-carrying Enterobacteriaceae isolated from the blood of two septicaemic neonates admitted to a neonatal intensive care unit.