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 β-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, 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.