Navegando por Palavras-chave "Metalo-Beta-Lactamase"

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    Caracterização fenotípica e molecular de Pseudomonas aeruginosa resistentes a carbapenêmicos e produtoras de Metalobeta- lactamase, isoladas em hemoculturas de crianças e adolescentes com câncer
    (Universidade Federal de São Paulo (UNIFESP), 2008-01-30) Fernandes, Thaís Ávila [UNIFESP]; Pignatari, Antonio Carlos Campos [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Pseudomonas aeruginosa is an important opportunist pathogen, particularly for oncologic and neutropenic hospitalized patients. One of the main characterisitic of this bacteria is the development of multiple antibiotic resistance, including the carbapenems. The first metallo-beta-lactamase (MBL) encoding the gene blaSPM-1 reported in the literature was isolated in the year 2000 from a patient admitted to the Instituto de Oncologia Pediatrica (IOP/GRAAC - UNIFESP). Objective: To evalute the prevalence of P. aeruginosa carbapenem resistant and MBL producers isolated from bloodstream samples collected from patients admitted to the IOP in the period 2000- 2005; to describe the dissemination of these enzymes by molecular typing and clinical/epidemiological data. Methods: 56 P. aeruginosa isolates from 49 patients were tested against 10 different antibiotics by disc diffusion. The isolates resistant to carbapenems were tested by disc-approximation method and submitted to PCR reaction for detection of MBLs genes. The isolates producers of blaSPM-1 were molecular typed by PFGE. The clinical and epidemiological data were obtained from the patiens charts. Results: From 2000 to 2005, 32 out of 56 P. aeruginosa isolates were classified as carbepenem reistant by disc diffusion. Eighteen out of 32 (56,2%) isolates carried blaSPM-1 and revealed the same molecular typing profile. We did not detected other MBL blaIMP-1, blaVIM-1 and blaVIM-2. The antibiotic therapy was considered adequate in only 17,7% of the patients with P. aeruginosa bacteremia encoding the gene blaSPM-1. We observed a higher letality rate, in the period of 30 days after bacteremia, in these patients compared with the letality of patients with P. aeruginosa bacteremia resistant to carbapenems but not carring MBL. Conclusion: We detected the presence of a P. aeruginosa clone resistant to carbapenems and carrying the gene blaSPM-1 that persisted in blood stream isolates of patients admitted to the IOP from 2000 to 2005. A high letality rate and inadequacy of initial antibiotic treatment was observed justifying a strict epidemiologic surveillance and re-evalutation of antibiotic treatment protocol.
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    Desenvolvimento 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 Paulo
    The 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.