Multiclonal outbreak of Klebsiella pneumoniae producing extended-spectrum β-lactamase CTX-M-2 and novel variant CTX-M-59 in a neonatal intensive care unit in Brazil

An outbreak of cephalosporin-resistant Klebsiella pneumoniae occurred in a neonatal intensive care unit in Sao Paulo, Brazil. Of the 10 pulsotypes identified during the outbreak and follow-up periods, nine produced CTX-M-2 or its new variant CTX-M-59 and one produced SRV-5. bla(CTX-M-2/59) genes were located on closely related plasmids that were transferable.