Navegando por Navegando por Palavras-chave "Pseudomonas Aeruginosa"
Agora exibindo 1 - 4 de 4
Resultados por página
Opções de Ordenação
- ItemAcesso aberto (Open Access)Caracterização molecular de amostras de Pseudomonas aeruginosa resistentes a Amicacina e Meropenem(Universidade Federal de São Paulo (UNIFESP), 2019-02-20) Santos, Paulo Henrique Dantas Dos [UNIFESP]; Pignatari, Antonio Carlos Campos [UNIFESP]; http://lattes.cnpq.br/9461346610553865; http://lattes.cnpq.br/7071042329034394; Universidade Federal de São Paulo (UNIFESP)Introduction: Pseudomonas aeruginosa infections in the hospital environment present high morbidity and mortality, particularly in immunocompromised patients, with high rates of multiresistance to antimicrobials including carbapenens and aminoglycosides. This study retrospectively analyzed isolates of P. aeruginosa resistant to amikacin and meropenem from nosocomial infections of the bloodstream and respiratory tract diagnosed in the participating medical centers of SCOPE Brazil and Hospital São Paulo. Methods: The sensitivity profile to amikacin and meropenem of 96 P. aeruginosa samples, identified by MALDI-TOF, was determined by dilution in agar. The presence of genes encoding enzyme resistance to meropenem and amikacin was evaluated by real-time PCR (qPCR) and the clonality profile by Pulsed Field Gel Electrophoresis (PFGE). Four samples with different minimum inhibitory concentrations (MIC) for amikacin were submitted to new generation sequencing (SNG). Results: Resistance to both antibiotics, amikacin and meropenem, was observed in 42 (43.75%) with very high MICs for amikacin (> 4,096 μg / ml). The blaSPM, rmtD, blaGES resistance genes were detected by the qPCR methodology. An association of samples with higher MICs for amikacin was observed when the detection of genes coding for the metalloenzyme blaSPM and the methylase rmtD was observed. The analysis of the clonality profile of the isolates resistant to amikacin by PFGE revealed 10 profiles, and the majority of isolates resistant to amikacin and meropenem are found in the same profile. The SNG analyzed by the online platforms Center for Genomic Epidemiology and MLST-Pasteur Database enabled the detection of resistance genes for β-lactams, aminoglycosides and fluoroquinolones, as well as ST of three isolates, especially ST 277 for international dissemination.
- ItemSomente MetadadadosDesenvolvimento e avaliação de duas técnicas para estudo de sinergia de combinações de antimicrobianos frente à Pseudomonas aeruginosa multirresistente(Universidade Federal de São Paulo (UNIFESP), 2021) Santos, Gerlan Da Rocha [UNIFESP]; Kiffer, Carlos Roberto Veiga [UNIFESP]; Universidade Federal de São PauloThe Metallo-β-lactamases (MβLs) enzymes identified in Pseudomonas aeruginosa are increasing sources of resistance, causing hydrolysis to almost all classes of β-lactams, except aztreonam. In addition, MβL-producing P. aeruginosa pose a significant threat to Brazilian health system, especially the Sao Paulo metallo-β-lactamase enzyme (SPM-1). In the presente study, we performed in vitro tests of drug combinations for MβL- and EsβL- (Extended-spectrum β-lactamase) producing P. aeruginosa in order to evaluate their synergistic activity. Initially, the presence of blaSPM-1, blaIMP, blaVIM, blaCTX-M e blaGES-1 genes was confirmed by the polymerase chain reaction (PCR) technique. The minimum inhibitory concentrations (MICs) for some antibiotics and isolates were determined by the broth microdilution or agar dilution method. Then epsilometer crossing tests were performed. In order to interpret the epsilometer crossing test results, the Fraction inhibitory concentration index (FICI) was calculated and the combinations were defined as: synergy (≤0,5), additive (0,5-1), no effect (1-4), and antagonism (≥4). Two of the best performing combinations were also studied by time-kill assay: ceftolozane/tazobactam-aztreonam (C/T-ATM) and ceftolozane/tazobactam-fosfomycin (C/T-FOS). A 88.8% synergy (24/27) was detected for C/T-FOS and 14.8% (4/27) for C/T-ATM by epsilometer crossing test. In comparison, C/T-FOS combination presented synergistic activity in one (1/6) by the time-kill assay. The C/T-ATM combination showed no activity against the six isolates tested by TK assay. In the context of increased resistance to carbapenems among P. aeruginosa, techniques that aim to analyze the synergistic effect and combinations of antimicrobials must studied and the findings may help identifying new treatment options.
- ItemSomente MetadadadosFrequência de β-lactamases de espectro estendido, carbapenemases e metilases em isolados clínicos contemporâneos de Pseudomonas aeruginosa(Universidade Federal de São Paulo (UNIFESP), 2020-11-26) Nascimento, Ezequiel Andre Do [UNIFESP]; Gales, Ana Cristina [UNIFESP]; Universidade Federal de São PauloInfections caused by Pseudomonas aeruginosa have become a major challenge for clinicians due to its intrinsic resistance as well as its incredible ability to acquire antimicrobial resistance genes. In this context, this study had aim to evaluate the resistance mechanisms in clinical isolates of P. aeruginosa recovered from blood cultures at São Paulo hospital between January 2013 to December 2017. During the study period, 273 P. aeruginosa isolates were recovered. In order to obtain a homogeneous and representative sample for the genotypic characterization, a total of 102 were randomly selected samples. The identification of bacterial isolates was carried out using the MALDI- TOF and later the isolates were submitted to the sensitivity test to antimicrobials by microdilution in broth and agar dilution. The search for genes that coded for β-Lactamaseses and methylases was performed by the PCR technique, followed by sequencing. The clonal relationship between the isolates was performed using the PFGE. The main resistance phenotype observed among the analyzed isolates was the of sensitivity to β-lactams ceftazidime, meropenem and imipenem. A total of 37% (n = 38) of the evaluated samples presented this phenotype. With 25% (n = 26), the second profile with the largest number of isolates was resistance to ceftazidime, imipenem and meropenem, followed by 19% (n = 19) of samples sensitive to ceftazidime and resistant to both carbapenems, meropenem and imipenem. When sensitivity to ceftazidime, to meropenem and resistance to imipenem, 6% of the total of isolates presented this phenotype. Only 5% of bacterial isolates showed sensitivity to ceftazidime, imipenem and resistance to meropenem. So much the phenotype of resistance to ceftazidime and sensitivity to carbapenems, as resistance to ceftazidime, meropenem and sensitivity to imipenem were found in only 4% of bacterial samples. Among the coding genes of β-lactamases investigated, 5 (n = 5) isolated carriers of the gene were found blaOXA-56, 5 (n = 5) of the blaSPM-1 gene, 5 (n = 5) of blaOXA-129 and 5 (n = 5) producers of blaCTX-M-2 gene. In addition to the genes encoding βlactamases, the gene encoding of rmtD-1 methylase was found in 8 isolates. These showed high rates of resistance (MIC> 64 μg / mL) to amikacin and gentamicin, with the exception of isolate P-14,041 who presented MICs of 8 and 8 μg / mL for amikacin and gentamicin. Among the 8 rmtD carrier isolates, 4 of them showed coproduction with other genes of resistance, being two rmtD + blaSPM-1 and two, rmtD + blaSPM-1 + blaOXA-56. The year 2013 was the one with the greatest number and diversity of resistance genes (n = 13). The presence of the blaSPM-1 gene was observed in three isolates in 2013 and, subsequently, in only one isolate in 2015 and another in 2017. The β- lactamase blaOXA-129 was found in a single isolate in the year 2013, one in 2014, one in 2016 and two isolates from the year 2017. The gene encoding β- lactamase blaOXA-56 was found in two isolates in 2013, two in 2015 and in one 2014. When evaluating aminoglycoside resistance genes, the gene for rmtD-1 methylase was found in a greater number of isolates in 2013 with three isolated, followed by 2016 (2 isolated) and the years 2015, 2016 and 2017 with only one isolate in each of those years. The analysis of genetic similarity performed separately for isolates producing the blaSPM-1 and blaOXA-129. The blaSPM-1 gene carrier isolates were associated with only one group clonal (A), which was divided into subgroups A1 (n = 3) and A2 (n = 1). In contrast, when evaluating the isolates producing the blaOXA-129 gene, these were grouped into two different clonal groups (B and C). There was a predominance of clonal group B, which is divided into subgroups B1 (n = 2), B2 (n = 1) and B3 (n = 1). The results found in this study allowed to know and identify production of the main circulating β-lactamases among P. aeruginosa isolates causing bloodstream infections in the evaluated hospital. These results are essential for triggering actions to control these infections.
- ItemSomente MetadadadosTestes conceituais relativos ao conhecimento terapêutico em Pseudomonas aeruginosa produtoras de São Paulo metalo-beta-lactamase (SPM-1)(Universidade Federal de São Paulo (UNIFESP), 2021) Cuba, Gabriel Trova [UNIFESP]; Kiffer, Carlos Roberto Veiga [UNIFESP]; Universidade Federal de São PauloObjective: Carbapenem-resistant Pseudomonas aeruginosa (CR-PSA) imposes great limitations on empirical therapeutic choices, which are further complicated by metallo-beta-lactamase production. In Brazil, local dissemination of São Paulo metallo-beta-lactamase last decade was detected. In this context, this study evaluated new therapeutical strategies of antimicrobial combination therapy against multidrug resistant P. aeruginosa Methods: Minimum Inhibitory Concentrations (MICs) were determined by broth microdilution and gradient strips. A total of 6 unrelated and representative carbapenem resistant strains carrying blaSPM-1, which were previously characterized by whole genome sequencing (WGS), were selected. First, synergy assessment by gradient diffusion strip crossing was performed between ceftolozane/tazobactam and aztreonam, Fosfomycin and ticarcillin/clavulanate; ticarcillin/clavulanate and aztreonam combination was also tested. Then, the most successful combinations were tested against 27 MDR PSA isolates carrying blaSPM-1 (n= 13), blaIMP (n= 4), blaVIM (n= 3), blaGES-1 (n=2) and blaCTX-M-like (n= 2), and 3 isolates with no acquired beta-lactamase production detected by gradient diffusion strip crossing. Finally, those combinations were also tested against six genetically unrelated SPM-1-producing isolates were also evaluated by time–kill analysis. Results: All carbapenem resistant P. aeruginosa isolates harbouring blaSPM-1, blaGES- 1 and blaIMP-1 were categorized as resistant to ceftolozane/tazobactam, meropenem and fosfomycin, with 70% being susceptible to aztreonam. No synergism between ceftolozane/tazobactam and meropenem, polymyxin or ticarcillin/clavulanate was reported. Synergism for ceftolozane/tazobactam and fosfomycin and ceftolozane/tazobactam and aztreonam combinations was observed for 88.9% (24/27) and 18.5% (5/27) of the isolates by gradient diffusion strip crossing, respectively. A 3- to 9-fold reduction in ceftolozane/ tazobactam MICs was observed, depending on the combination. Ceftolozane/tazobactam and fosfomycin was synergistic by TKA against one of six SPM-1-producing isolates, with additional nonsynergistic bacterial density reduction for another isolate. Aztreonam peak concentrations alone demonstrated a more than 3 log10 cfu/mL reduction against all six isolates, but all strains were within the susceptible range for the drug.xi Ticarcillin/clavulanate and aztreonam against SPM-1 producers showed a synergistic (n = 3) and additive (n = 2) effects. Conclusions: In the context of increasing carbapenem resistance among P. aeruginosa isolates worldwide, new combinations and stewardship strategies may need to be explored in the face of increasingly difficult to treat Gram-negative pathogens. Ceftolozane/tazobactam plus fosfomycin combination were synergistic when tested by gradient diffusion strip crossing and time kill analysis and ticarcillun/clavulanate plus aztreonam was synergistic against SPM-1 producing P. aeruginosa. These results, although limited, may be promising for guiding further in vivo studies. Combining biochemical properties with knowledge of resistance mechanisms might lead to innovative therapeutic approaches.