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.
Metallo-beta-lactamase production is emerging worldwide as an important mechanism of carbapenem resistance among nonfermentative Gram-negative isolates, and this mechanism is becoming frequently observed in Brazil. This study documents the occurrence and characteristics of an epidemic SPM-1-producing Pseudomonas aeruginosa strain in a teaching hospital located in Rio de Janeiro City, Brazil. The bla (SPM-1) gene and a class 1 integron were detected in 13 isolates, representing 20% of the 65 imipenem-resistant P. aeruginosa isolates obtained from January, 2000, to August, 2001. DNA sequencing revealed that this integron carries three gene cassettes that confer resistance to antimicrobials, aacA4, bla (OXA-56), and aadA7, and an orf1 encoding a putative transposase. All 13 SPM-producing P. aeruginosa isolates had closely related pulsed-field gel electrophoresis (PFGE) profiles, designated as clonal group A, suggesting nosocomial spread of the strain. This clonal group was the same as that observed in other SPM-1-producing P. aeruginosa isolates from distinct Brazilian states. The dissemination of this clone throughout Brazil could not be explained by transfer of infected patients and/or sharing of common health-care staff. It is likely that the spread of these strains occurred indirectly via the community.
Bacteria of Stenotrophomonas maltophilia have been isolated with increasing frequency from the airways of cystic fibrosis (CF) patients, usually following P. aeruginosa infections, but their adherence to human epithelial respiratory cells has never been investigated. In this study, various S. maltophilia strains were seen to adhere to epithelial respiratory cells in vitro, mainly along intercellular junctions. Bacteria could also enter into host cells, as determined by the gentamicin exclusion assay and transmission electron microscopy. Cells co-incubated with P. aeruginosa and S. maltophilia exhibited a significantly decreased adherence of these latter bacteria. No decrease in S. maltophilia adherence was observed when co-infection was carried out with heat-killed P. aeruginosa or when respiratory cells were first incubated with P. aeruginosa, before incubation with S. maltophilia. Our data suggest that P. aeruginosa infections do not account for the increased prevalence of S. maltophilia in CF patient airways, that thermolabile products from P. aeruginosa can control the adherence of S. maltophilia to respiratory cells and also that these two bacteria do not compete for cell receptors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.