Dissemination and clinical implications of multidrug-resistant Klebsiella pneumoniae isolates producing OXA-48 in a Spanish hospital.

BACKGROUND: Healthcare-associated infections caused by Klebsiella pneumoniae isolates are increasing and few effective antibiotics are currently available to treat patients. AIM: To assess the epidemiology, molecular basis, clinical features, and outcomes in the acquisition and dissemination of OXA-48-producing K. pneumoniae (OXA48KP) in a tertiary Spanish hospital between October 2013 and December 2015. METHODS: Clinical, demographic, and microbiological data of patients with OXA48KP in clinical samples were collected from medical records. Carbapenemase genes were detected by polymerase chain reaction. Genetic relationships were determined by pulsed-field gel electrophoresis and multi-locus sequence typing. FINDINGS: In all, 116 episodes of OXA48KP in clinical samples were identified. The most frequent types of infection were urinary tract (N = 43, 42%), secondary bloodstream (N = 18, 17%), and surgical site infection (N = 17, 17%). More than one-quarter (28%) of infected patients died in hospital. Among infected patients (N = 90, 78%), infections were mainly classified as hospital-acquired (N = 70, 88%). A high number of OXA48KP isolates showed multidrug resistance, with highest susceptibility to colistin (86%), gentamicin (69%) and amikacin (59%). Most (87%) isolates were included in a main cluster. Seven (N = 8, 88%) isolates showed an identical allelic profile, associated with ST15. Only the isolate from cluster P8 was associated with ST29. The results confirm high dissemination of OXA48KP in our hospital due to the main clone ST15. OXA48KP infection was associated with a high mortality and was mainly hospital-acquired. CONCLUSION: This study highlights the importance of active surveillance programmes, especially those focusing on hospital readmissions in order to control the spread of carbapenemase-producing Enterobacteriaceae.

Concurrent interspecies and clonal dissemination of OXA-48 carbapenemase.

Several isolates of four different carbapenemase-producing Enterobacteriaceae species were recovered from a patient hospitalized for 4 months in a teaching hospital in Madrid. These species comprised seven Klebsiella pneumoniae belonging to ST15, four Escherichia coli belonging to ST2531, two Serratia marcescens and one Citrobacter freundii. This patient was the index case of a small outbreak of four patients infected and/or colonized by carbapenemase-producing K. pneumoniae. Molecular results identified the bla(OXA-48) gene in all Enterobacteriaceae isolates from the index case and in all isolates from the other three patients, suggesting intra- and interpatient dissemination. Our results highlight the great ability of OXA-48 carbapenemase to spread among different enterobacterial species by both clonal and nonclonal dissemination.