ATYPICAL PHENOTYPIC CHARACTERISTICS OF KLEBSIELLA PNEUMONIAE ISOLATES FROM AN OUTBREAK IN A NEONATAL INTENSIVE CARE UNIT IN BRAZIL

Extended-spectrum β-Lactamase-producing (ESBL) Klebsiella sp. isolates from an outbreak in a Neonatal Intensive Care Unit (NICU) at a teaching hospital in Londrina, Paraná State, Brazil, presented atypical phenotypic characteristics that hampered their identification and the distinction between Klebsiella and Enterobacter species. Ten isolates were identified as K. pneumoniae due to negative reactions for motility and inducible β-lactamase test (ESBL and AmpC) despite being positive for ornithyne descarboxilase. These isolates were genotyped by ribotyping and polymerase chain reaction (PCR) with repetitive extragenic palindromic sequences (REP). Ribotyping by means of an automated instrument and EcoRI and Pvu II as restriction enzymes resulted indetection of K. pneumoniae subspecie pneumoniae RIBO1 222-36-S-5 ribotype. Typing by REP-PCR showed that the 17 isolates from the outbreak were highly similar, belonging to one cluster with 100 % of similarity, and that they presented more than 70 % of similarity with K. pneumoniae ATCC 13883 and ATCC 10031, and 25 % of similarity with E. aerogenes CDC 1680. In conclusion, the isolates of the outbreak were identified as Klebsiella pneumoniae, despite presenting ornithyne descarboxilase enzyme, which is an atypical characteristic of this Klebsiella species