Rapid Expansion of KPC-2-Producing Klebsiella pneumoniae Isolates in Two Texas Hospitals due to Clonal Spread of ST258 and ST307 Lineages

During 2007 to 2010, 23 carbapenem-resistant Enterobacteriaceae strains were recovered in two hospitals in Texas among three institutions surveyed. Eighteen (2.0% overall) strains carried bla(KPC-2) and were collected in 2008 (3/150; 2.0%) and 2010 (15/289; 5.1%). Clonality was noted within hospitals and ten isolates belonged to ST258. All strains carried bla(KPC-2) on plasmids and 14 had this gene embedded in Tn4401a. Tn3 transposase was detected upstream of bla(KPC-2) in two isolates and another strain had two adjacent copies of bla(KPC). Surveillance in prior years shows sporadic detection of KPC-producers in Texas, however, a recent increase in carbapenem-resistant Enterobacteriaceae in this state was due to the spread of KPC-producing Klebsiella pneumoniae, including isolates from ST258.