Elizabeth Andrade Marques

Eicosanoid-mediated proinflammatory activity of Pseudomonas aeruginosa ExoU

As Pseudomonas aeruginosa ExoU possesses two functional blocks of homology to calcium‐independent (iPLA2) and cytosolic phospholipase A2 (cPLA2), we addressed the question whether it would exhibit a proinflammatory activity by enhancing the synthesis of eicosanoids by host organisms. Endothelial cells from the HMEC‐1 line infected with the ExoU‐producing PA103 strain exhibited a potent release of arachidonic acid (AA) that could be significantly inhibited by methyl arachidonyl fluorophosphonate (MAFP), a specific PLA2 inhibitor, as well as significant amounts of the cyclooxygenase (COX)‐derived prostaglandins PGE2 and PGI2. Cells infected with an isogenic mutant defective in ExoU synthesis did not differ from non‐infected cells in the AA release and produced prostanoids in significantly lower concentrations. Infection by PA103 induced a marked inflammatory response in two different in vivo experimental models. Inoculation of the parental bacteria into mice footpads led to an early increase in the infected limb volume that could be significantly reduced by inhibitors of both COX and lipoxygenase (ibuprofen and NDGA respectively). In an experimental respiratory infection model, bronchoalveolar lavage (BAL) from mice instilled with 104 cfu of PA103 exhibited a marked influx of inflammatory cells and PGE2 release that could be significantly reduced by indomethacin, a non‐selective COX inhibitor. Our results suggest that ExoU may contribute to P. aeruginosa pathogenesis by inducing an eicosanoid–mediated inflammatory response of host organisms.

Molecular epidemiology of KPC-2- producing Klebsiella pneumoniae isolates in Brazil: the predominance of sequence type 437

The aim of this study was to investigate the genetic relatedness of 57 KPC-2-producing Klebsiella pneumoniae isolates from 5 states in Brazil, during 2006-2009. Pulse-field gel electrophoresis analysis identified 10 pulsotypes. The pulsotype designated as Kp-RJ (Klebsiella pneumoniae-Rio de Janeiro) was the dominant clone found in the states of Rio de Janeiro and Espírito Santo. Multilocus sequence typing of Kp-RJ assigned it to ST 437. Sequence types ST11, ST16, ST25, ST70, ST101, ST105, ST423, ST442, and ST443 were also identified. These results indicate the dissemination of a successful KPC-producing clone (ST437) in Brazil, which is a single locus variant of ST258.

Achromobacter xylosoxidans: Characterization of Strains in Brazilian Cystic Fibrosis Patients

ABSTRACT We investigated the possibility of cross-infection among cystic fibrosis patients in two Brazilian reference centers. Achromobacter xylosoxidans isolates (n = 122) were recovered over a 5-year period from 39 patients. Isolates were genetically heterogeneous, but one genotype was present in 56% of the patients, suggesting that cross-infection may have occurred.

Burkholderia cenocepacia, B. multivorans, B. ambifaria and B. vietnamiensis isolates from cystic fibrosis patients have different profiles of exoenzyme production

Knowledge about the virulence mechanisms of species from the Burkholderia cepacia complex (BCC) is still limited. The genomovar heterogeneity and production of different virulence factors are likely to contribute to the variation in the clinical outcome observed in BCC‐infected cystic fibrosis (CF) patients. Therefore, in this study we investigated the genetic polimorphism, the presence of genetic makers associated with virulence and transmissibility in BCC, and the profile of exoenzyme production of 59 BCC isolates obtained from 59 CF patients attending the reference CF centre in Rio de Janeiro, Brazil. The DNA sequence analyses of the recA gene allowed us to identify 40 of these 59 BCC species as being B. cenocepacia, 9 as B. vietnamiensis, 6 as B. multivorans and 4 as B. ambifaria. The assessment of the bacterial genetic polymorphism by PFGE revealed that B. cenocepacia and the B. multivorans isolates belonged to four and two different PFGE profiles with prevalence of two clones, A and B, respectively. All B. vietnamiensis and B. ambifaria belonged to only one PFGE profile (J and E, respectively). None of the isolates exhibited the genetic markers cblA and BCESM, assessed by polymerase chain reaction. In contrast, the profile of enzymatic activity, assessed by phenotypic methods, differed among the BCC species: protease activity was detected only in B. cenocepacia and B. ambifaria isolates, whereas only B. vietnamiensis isolates produced hemolysin. Although the phospholipase C activity was similar among the different species, the level of lipase activity produced by B. multivorans was higher than in the other species. We speculate that the differential characteristics of exoenzyme production may account for the differences in the pathogenic potentials of each BCC species.

Detection of NDM-1-, CTX-M-15-, and qnrB4-Producing Enterobacter hormaechei Isolates in Brazil

Ana Paula D’Alincourt Carvalho-Assef, Polyana S. Pereira, Rodolpho M. Albano, Gabriela Casemiro Berião, Carolina Padilha Tavares, Thiago Pavoni Gomes Chagas, Elizabeth A. Marques, Loeci N. Timm, Renato C. F. Da Silva, Diego R. Falci, Marise D. Asensi Laboratório de Pesquisa em Infecção Hospitalar (LAPIH), Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, RJ, Brazil; Departamento de Bioquímica, Instituto de Biologia Roberto Alcântara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Fundação Estadual de Produção e Pesquisa em Saúde (FEPPS IPB-LACEN-RS), Porto Alegre, RS, Brazil; Hospital Nossa Senhora da Conceição, Porto Alegre, RS, Brazil

Corynebacterium pseudodiphtheriticum isolated from relevant clinical sites of infection: a human pathogen overlooked in emerging countries

Aims:  To examine the occurrence of and to determine the antimicrobial susceptibility of Corynebacterium pseudodiphtheriticum among patients with bacterial infections at a teaching hospital.

Multidrug-Resistant Nontuberculous Mycobacteria Isolated from Cystic Fibrosis Patients

ABSTRACT Worldwide, nontuberculous mycobacteria (NTM) have become emergent pathogens of pulmonary infections in cystic fibrosis (CF) patients, with an estimated prevalence ranging from 5 to 20%. This work investigated the presence of NTM in sputum samples of 129 CF patients (2 to 18 years old) submitted to longitudinal clinical supervision at a regional reference center in Rio de Janeiro, Brazil. From June 2009 to March 2012, 36 NTM isolates recovered from 10 (7.75%) out of 129 children were obtained. Molecular identification of NTM was performed by using PCR restriction analysis targeting the hsp65 gene (PRA-hsp65) and sequencing of the rpoB gene, and susceptibility tests were performed that followed Clinical and Laboratory Standards Institute recommendations. For evaluating the genotypic diversity, pulsed-field gel electrophoresis (PFGE) and/or enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR) was performed. The species identified were Mycobacterium abscessus subsp. bolletii (n = 24), M. abscessus subsp. abscessus (n = 6), Mycobacterium fortuitum (n = 3), Mycobacterium marseillense (n = 2), and Mycobacterium timonense (n = 1). Most of the isolates presented resistance to five or more of the antimicrobials tested. Typing profiles were mainly patient specific. The PFGE profiles indicated the presence of two clonal groups for M. abscessus subsp. abscessus and five clonal groups for M. abscesssus subsp. bolletii, with just one clone detected in two patients. Given the observed multidrug resistance patterns and the possibility of transmission between patients, we suggest the implementation of continuous and routine investigation of NTM infection or colonization in CF patients, including countries with a high burden of tuberculosis disease.

Performance of MALDI-ToF MS for species identification of Burkholderia cepacia complex clinical isolates☆ , ☆☆

We evaluated the performance of matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) for identification of Bcc species compared with that of recA sequencing. MALDI-ToF was able of identifying 100% of Bcc isolates at the genus level, but 23.1% of Bcc isolates tested were not correctly identified at the species level. The misidentification occurred most frequently with Burkholderia contaminans (100%) and B. cepacia (33.3%).

Mycobacterium massiliense BRA100 strain recovered from postsurgical infections: resistance to high concentrations of glutaraldehyde and alternative solutions for high level disinfection

PURPOSE To evaluate the minimum inhibitory concentration (MIC) of GTA against these microorganisms and alternative disinfectants for high-level disinfection (HLD). METHODS Reference mycobacteria and clinical M. massiliense strains were included in this study. Active cultures were submitted to susceptibility qualitative tests with GTA dilutions (ranging from 1.5% to 8%), and commercial orthophthaldehyde (OPA) and peracetic acid (PA)-based solutions, during the period of exposure as recommended by National Agency of Sanitary Surveillance for HLD. RESULTS All reference and M. massiliense non-BRA100 strains, recovered from sputum, were susceptible to any GTA concentration, OPA and PA solutions. M. massiliense BRA100 strains presented MIC of 8% GTA and were susceptible to OPA and PA. CONCLUSION M. massiliense BRA100 strain is resistant to high GTA concentrations (up to 7%), which proves that this product is non-effective against specific rapidly growing mycobacteria and should be substituted by OPA or PA-based solutions for HLD.

Stenotrophomonas maltophilia Interaction with Human Epithelial Respiratory Cells In Vitro

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.