Diversity of clonal types of Klebsiella pneumoniae causing infections in intensive care neonatal patients in a large urban setting

Background Klebsiella infections are reported from neonatal intensive care units (NICUs) worldwide, but data on their incidence and genetic diversity remain scarce. Objective We determined the incidence and genetic diversity of Klebsiella infections in NICU patients in Rio de Janeiro. Methods This was a prospective study including newborns admitted to NICU in three hospitals during April 2005-November 2006 and March 2008-February 2009. Klebsiella pneumoniae isolates were genotyped by multilocus sequence typing (MLST) and extended spectrum beta-lactamases (ESBL) were characterized. Results Klebsiella infections occurred in 38 of 3984 patients (incidence rate, 9.5/1000 admissions); 14 (37%) of these 38 newborns died. Two clonal groups, CC45 and CC1041, caused 11 cases (42% of K. pneumoniae infection). Ten (32%) of the isolates causing infection produced ESBL, 9 of which (83%) carried bla(CTX-M-15), all belonging to clonal complex (CC) 45 and CC1041. Nine of these ESBL-producing isolates were confined to only one of the NICUs. Major conclusions The high incidence of Klebsiella infections in NICU in Rio de Janeiro appeared to be due to a combination of frequent sporadic infections caused by multiple K. pneumoniae genotypes and small outbreaks caused by dominant multidrug-resistant clones.