Genomic insights into the diversity, virulence and resistance of Klebsiella pneumoniae extensively drug resistant clinical isolates.

Klebsiella pneumoniae has been implicated in wide-ranging nosocomial outbreaks, causing severe infections without effective treatments due to antibiotic resistance. Here, we performed genome sequencing of 70 extensively drug resistant clinical isolates, collected from Brasília's hospitals (Brazil) between 2010 and 2014. The majority of strains (60 out of 70) belonged to a single clonal complex (CC), CC258, which has become distributed worldwide in the last two decades. Of these CC258 strains, 44 strains were classified as sequence type 11 (ST11) and fell into two distinct clades, but no ST258 strains were found. These 70 strains had a pan-genome size of 10 366 genes, with a core-genome size of ~4476 genes found in 95 % of isolates. Analysis of sequences revealed diverse mechanisms of resistance, including production of multidrug efflux pumps, enzymes with the same target function but with reduced or no affinity to the drug, and proteins that protected the drug target or inactivated the drug. ß-Lactamase production provided the most notable mechanism associated with K. pneumoniae. Each strain presented two or three different ß-lactamase enzymes, including class A (SHV, CTX-M and KPC), class B and class C AmpC enzymes, although no class D ß-lactamase was identified. Strains carrying the NDM enzyme involved three different ST types, suggesting that there was no common genetic origin.

Isolation of blaNDM-producing Enterobacteriaceae in a public hospital in Salvador, Bahia, Brazil.

Carbapenemases have great importance in the global epidemiological scenario since infections with carbapenemase-producing bacteria are associated with high mortality, especially in hospitalized patients in intensive care units. This study describes two microorganisms producers of the New Delhi Metallo-b-lactamase, Klebsiella pneumoniae and Citrobacter freundii, from two patients admitted to a public hospital in Salvador, Bahia. These are the first clinical cases of New Delhi Metallo-b-lactamase described in microorganisms in the north and northeast Brazil. The isolates were characterized by antimicrobial susceptibility test, with resistance to all ß-lactams including carbapenems, negative Modified Hodge Test and the synergy test with Ethylenediaminetetraacetic acid, Phenylboronic Acid and Cloxacillin was positive only with Ethylenediaminetetraacetic acid (difference of >5mm in the inhibition zone between the disk without and with the inhibitor). Analysis by multiplex PCR for blaIMP, blaVIM, blaNDM, blaKPC and blaOXA-48 enzymes confirmed the presence of blaNDM gene. This report of two different New Delhi Metallo-b-lactamase-producing microorganisms in a different region of Brazil confirms the risk of spreading resistance genes between different species and emphasizes the need for prevention and control of infections caused by these pathogens, which have limited treatment options and have been linked to high mortality rates.

Molecular epidemiology of KPC-2-producing Enterobacteriaceae (non-Klebsiella pneumoniae) isolated from Brazil.

In Brazil, since 2009, there has been an ever increasing widespread of the bla(KPC-2) gene, mainly in Klebsiella pneumoniae. This study aims to assess the molecular epidemiology and genetic background of this gene in Enterobacteriaceae (non-K. pneumoniae) species from 9 Brazilian states between 2009 and 2011. Three hundred eighty-seven isolates were analyzed exhibiting nonsusceptibility to carbapenems, in which the bla(KPC-2) gene was detected in 21.4%. By disk diffusion and E-test, these isolates exhibited high rates of resistance to most of the antimicrobials tested, including tigecycline (45.6% nonsusceptible) and polymyxin B (16.5%), the most resistant species being Enterobacter aerogenes and Enterobacter cloacae. We found great clonal diversity and a variety of bla(KPC-2)-carrying plasmids, all of them exhibiting a partial Tn4401 structure. Therefore, this study demonstrates the dissemination of KPC-2 in 9 Enterobacteriaceae species, including species that were not previously described such as Pantoea agglomerans and Providencia stuartii.

Isolation of blaNDM-producing Enterobacteriaceae in a public hospital in Salvador, Bahia, Brazil

ABSTRACT Carbapenemases have great importance in the global epidemiological scenario since infections with carbapenemase-producing bacteria are associated with high mortality, especially in hospitalized patients in intensive care units. This study describes two microorganisms producers of the New Delhi Metallo-b-lactamase, Klebsiella pneumoniae and Citrobacter freundii, from two patients admitted to a public hospital in Salvador, Bahia. These are the first clinical cases of New Delhi Metallo-b-lactamase described in microorganisms in the north and northeast Brazil. The isolates were characterized by antimicrobial susceptibility test, with resistance to all β-lactams including carbapenems, negative Modified Hodge Test and the synergy test with Ethylenediaminetetraacetic acid, Phenylboronic Acid and Cloxacillin was positive only with Ethylenediaminetetraacetic acid (difference of >5 mm in the inhibition zone between the disk without and with the inhibitor). Analysis by multiplex PCR for blaIMP, blaVIM, blaNDM, blaKPC and blaOXA-48 enzymes confirmed the presence of blaNDM gene. This report of two different New Delhi Metallo-b-lactamase-producing microorganisms in a different region of Brazil confirms the risk of spreading resistance genes between different species and emphasizes the need for prevention and control of infections caused by these pathogens, which have limited treatment options and have been linked to high mortality rates.