Metallo-β-Lactamase (MBL)-Producing Enterobacteriaceae in United States Children

Metallo-β-lactamase-producing Enterobacteriaceae are emerging in the U.S. and are becoming a significant threat. Unfortunately, there is little recognition of the increasing reports of these organisms in U.S. children, a vulnerable population that may suffer severe long-term consequences.
Metallo-β-lactamases (MBLs) are emerging as the most notable resistance determinants in Enterobacteriaceae. In many cases, the genes encoding MBLs are part of complex, mobile genetic elements that carry other resistance determinants. In the United States, there are increasing reports of MBL-producing Enterobacteriaceae, with New Delhi MBLs (NDMs) accounting for the majority of transmissible MBL infections. Many infections caused by NDM-producing bacteria are associated with international travel and medical tourism. However, little recognition of the introduction of MBL-producing Enterobacteriaceae into the pediatric community has followed. Reports suggest that this occurred as early as 2002. Here, we reflect on the unwelcome emergence of MBL-producing Enterobacteriaceae in US children and the available clinical and molecular data associated with spread. Since 2002, there have been disturbing reports that include the most readily transmissible MBLs, blaIMP, blaVIM, and blaNDM types. In the majority of children with available data, a history of foreign travel is absent.