Early Dissemination of KPC-2-Producing Klebsiella pneumoniae Strains in Brazil

A recent publication by Monteiro et al. reported the first detection of KPC-2 β-lactamase in carbapenem-resistant Klebsiella pneumoniae strains in Brazil, which occurred in 2006 (5). The authors reported that, between September and November of 2006, four carbapenem-resistant K. pneumoniae strains, harboring the bla_KPC-2 gene, were isolated from four patients hospitalized in a hospital in the city of Recife, northeastern Brazil. Just 1 month after their letter was published, detection of KPC-2 carbapenemase was also reported in six K. pneumoniae isolates recovered from two hospitals (from September 2007 to May 2008) in Rio de Janeiro, southeastern Brazil (7). Moreover, in the last year, another three groups of investigators reported, in different national meetings, the emergence of KPC-2 carbapenemase-producing K. pneumoniae in São Paulo and Rio de Janeiro (1, 2, 9). Here, we present evidence that KPC-producing K. pneumoniae has been emerging in Brazilian hospitals since at least 2005. In this regard, from 2003 to 2008, we have conducted a regional carbapenem-resistant surveillance survey in order to determine the occurrence of carbapenemases in gram-negative isolates from clinical settings in the southeastern region of Brazil. Currently, we have identified 31 imipenem-resistant Enterobacteriaceae isolates from eight medical centers, which were screened for the presence of carbapenemases and genes encoding IMP, VIM, and KPC β-lactamases, using the combined disk assay with disks containing ceftazidime, imipenem, meropenem, or cefepime, either alone or in combination with 400 μg of boronic acid or 100 mM EDTA, and DNA amplification by PCR, respectively. Eight imipenem-resistant isolates (six isolates of K. pneumoniae, one isolate of Providencia rettgeri, and one isolate of Enterobacter sp.) carried the bla_IMP-1 class B metallo-β-lactamase gene (3, 8), whereas two K. pneumoniae strains isolated in May 2005 (FCF13/05) and November 2007 (FCF35/07) carried the bla_KPC-2 class A carbapenemase gene. Both KPC-2-producing K. pneumoniae isolates, which had been recovered from blood cultures from two patients in two medical centers in São Paulo City, were not clonally related and showed resistance to all β-lactam antibiotics, including cefoxitin (MIC of 256 μg/ml), ceftazidime (MIC of ≥64 μg/ml), imipenem (MIC of ≥32 μg/ml), meropenem (MIC of ≥256 μg/ml), and ertapenem (MIC of ≥256 μg/ml). The production of KPC-2 was associated with a positive bioassay (i.e., satellite growth of Micrococcus luteus ATCC 9341 around the K. pneumoniae strain, growing on Mueller-Hinton agar plates containing 10⁸ CFU of the ATCC strain/ml and imipenem at a concentration of 0.06 or 0.12 μg/ml) and boronic acid inhibition tests (10), whereas the presence of the bla_KPC-2 gene was confirmed by PCR and sequencing (GenBank accession no. FJ641196 and FJ641197). Therefore, KPC-2-producing K. pneumoniae seems to have emerged in São Paulo in 2005 and was later observed in two other states in Brazil, as opposed to IMP-1-producing K. pneumoniae, which emerged in Brazil in 2003 (4) and has been detected only in São Paulo state so far (3). Since KPC-2-producing strains have already become established in Latin America (1, 2, 5-7, 9, 11, 12), we emphasize the need for continuous local surveillance programs in order to prevent the wide spread of these strains.