Dissemination of carbapenem-resistant Enterobacteriaceae (CRE) poses a considerable threat to public health. Infections caused by CRE have limited treatment options and have been associated with high mortality rates. This resistance is largely the consequence of acquisition of carbapenemase genes. The genotypes in the geographical areas were initially different, as the Japanese epidemic was related to the IMP type (Class B), whereas the US epidemic was related to the KPC type (Class A). Thus, clinical detection of carbapenemase producers remains difficult based on each genotypes has specific screening method. CRE has many problems: some carbapenemase producers were susceptible to the carbapenems and some CRE were not producing carbapenemase which is associated with porin loss or efflux pomp. This review describes the current situation of CRE. It would facilitate accurate detection of CRE and approaches to prevention and treatment.