[Molecular characterization of carbapenem-resistant and metallo-beta-lactamase-producing Pseudomonas aeruginosa isolated from blood cultures from children and teenagers with cancer]. / Caracterização molecular de Pseudomonas aeruginosa resistentes a carbapenêmicos e produtoras de metalo-beta-lactamase isoladas em hemoculturas de crianças e adolescentes com câncer.

INTRODUCTION: The objective of this study was to evaluate the prevalence and dissemination of carbapenem-resistant and metallo-beta-lactamase-producing Pseudomonas aeruginosa isolated from blood-stream samples (2000-2005) that were collected from patients admitted to the Institute of Pediatric Oncology, UNIFESP (IOP-GRAACC). METHODS AND RESULTS: Fifty-six P. aeruginosa samples were isolated from 49 patients. Thirty-two of these samples were classified as carbapenem-resistant using the disc diffusion method and were subjected to the PCR reaction in order to detect MBL genes. Eighteen of these 32 isolates showed the blaSPM-1 gene. Eight samples selected in different years over the study period presented the same genetic profile according to pulsed-field gel electrophoresis. The antimicrobial therapy was considered adequate for only 23.5% of the patients with bacteremia due to P. aeruginosa carrying the blaSPM-1 gene, and a high lethality rate of 70.6% was observed during the 30-day period after bacteremia and an inadequate initial antibiotic regimen. CONCLUSIONS: We detected the presence of a clone of carbapenem-resistant P. aeruginosa carrying blaSPM-1 that persisted in blood culture samples over a six-year period at the institution, with high lethality, thus justifying rigorous epidemiological surveillance and a rearrangement of the antimicrobial therapy regimens at the institution.

Caracterização molecular de Pseudomonas aeruginosa resistentes a carbapenêmicos e produtoras de metalo-β-lactamase isoladas em hemoculturas de crianças e adolescentes com câncer / Molecular characterization of carbapenem-resistant and metallo-β-lactamase-producing Pseudomonas aeruginosa isolated from blood cultures from children and teenagers with cancer

INTRODUCÃO: O objetivo do estudo foi avaliar a prevalência e a disseminação de amostras de Pseudomonas aeruginosa resistente aos carbapenêmicos e produtoras de metalo-β-lactamases isoladas de hemoculturas (2000-2005) de pacientes do Instituto de Oncologia Pediátrica da UNIFESP (IOP-GRAACC). MÉTODOS E RESULTADOS: Cinquenta e seis amostras de Pseudomonas aeruginosa foram isoladas de 49 pacientes. Trinta e duas dessas amostras foram classificadas como resistentes aos carbapenêmicos pela técnica de disco difusão e submetidas a reação de PCR para detecção de genes de MBL. Dezoitos dessas 32 amostras evidenciaram o gene blaSPM-1. Oito amostras selecionadas em diferentes anos no período de estudo apresentaram o mesmo perfil genético por pulsed-field gel electrophoresis. A terapêutica antimicrobiana foi considerada adequada em apenas 23,5 por cento dos pacientes com bacteremia por P. aeruginosa carreando blaSPM-1 e letalidade de 70,6 por cento no período de até 30 dias após a bacteremia e uma inadequação inicial dos esquemas antibióticos utilizados CONCLUSÕES: Evidenciamos a presença de um clone de P. aeruginosa resistente aos carbapenêmicos carreando blaSPM-1 que persistiu em amostras de hemocultura pelo período de 6 anos na instituição, com alta letalidade, justificando uma vigilância epidemiológica rigorosa e uma readequação dos esquemas de terapia antimicrobianos na instituição.

INTRODUCTION: The objective of this study was to evaluate the prevalence and dissemination of carbapenem-resistant and metallo-β-lactamase-producing Pseudomonas aeruginosa isolated from blood-stream samples (2000-2005) that were collected from patients admitted to the Institute of Pediatric Oncology, UNIFESP (IOP-GRAACC). METHODS AND RESULTS: Fifty-six P. aeruginosa samples were isolated from 49 patients. Thirty-two of these samples were classified as carbapenem-resistant using the disc diffusion method and were subjected to the PCR reaction in order to detect MBL genes. Eighteen of these 32 isolates showed the blaSPM-1 gene. Eight samples selected in different years over the study period presented the same genetic profile according to pulsed-field gel electrophoresis. The antimicrobial therapy was considered adequate for only 23.5 percent of the patients with bacteremia due to P. aeruginosa carrying the blaSPM-1 gene, and a high lethality rate of 70.6 percent was observed during the 30-day period after bacteremia and an inadequate initial antibiotic regimen. CONCLUSIONS: We detected the presence of a clone of carbapenem-resistant P. aeruginosa carrying blaSPM-1 that persisted in blood culture samples over a six-year period at the institution, with high lethality, thus justifying rigorous epidemiological surveillance and a rearrangement of the antimicrobial therapy regimens at the institution.