Early OXA-48-Producing Isolates Recovered in a Spanish Hospital Reveal a Complex Introduction Dominated by Sequence Type 11 (ST11) and ST405 Klebsiella pneumoniae Clones.

Carbapenemase-producing (CPE) have become an important public health concern. In our hospital, VIM enzymes were first detected in 2005, carbapenemase (KPC) enzymes in 2009, and OXA-48 enzymes in 2012. We assess the population biology of the first OXA-48-producing isolates recovered in our hospital (2012 to 2013) where infections by other carbapenemases had been endemic for several years. Over a 21-month period, 71 isolates (61 , 5 , 2 , and 1 each of , , and ) recovered from clinical and surveillance specimens from 57 patients (22.8% nonhospitalized) were investigated for OXA-48-like-producing enzymes. Analyses for characterization and determination of the location of the gene, plasmid transferability, sequence, and clonal relatedness were performed. Most of the isolates also coproduced CTX-M-15 (57/71, 80.3%) and/or VIM-1 (7/71, 9.8%). was predominantly identified as sequence type 11 (ST11) (63.4%) and ST405 (9.8%) and as ST540, ST1406, ST3163, and ST4301. The gene was part of Tn located at the gene of plasmids (ca. ≥50 kb) of the IncL/M group, also carrying and genes. We selected one ST11 isolate for whole-genome sequencing in which we studied the plasmid containing the gene. This plasmid was compared with indexed plasmids existing in NCBI database by the use of BRIG and MAUVE. Our data suggest a rapid spread of genes between commonly isolated high-risk clones of species, frequently associated with antibiotic resistance. Moreover, the emergence of the multiresistant ST11 clone among nonhospitalized patients emphasizes the difficulty of preventing its dissemination into the community. We present results of microbiological analysis of the first isolates that were isolated in 2012 in our institution expressing OXA-48 carbapenemase. This enzyme confers resistance to carbapenems, an important group of antibiotics widely used in the hospitals. OXA-48 carbapenemase is currently present in many parts of the world, but it is found particularly frequently in the Mediterranean area. It was disseminated at the Ramón y Cajal Hospital and found to be associated with a particular strain, so-called high-risk clone ST11, which was previously found in our institution in association with other enzymes such as CTX-M-15, VIM-1, and KPC-3. This clone might have acquired a plasmid harboring the gene. Our results point out the importance of local epidemiology in the dissemination and maintenance of multidrug-resistant bacteria.