RESUMO
Resumen Introducción: Pseudomonas aeruginosa es relevante en infecciones asociadas a la atención de salud, principalmente cuando presenta resistencia a carbapenémicos. Objetivos: Estudiar la producción de carbapenemasas en P. aeruginosa, con susceptibilidad disminuida a carbapenémicos procesadas en el Laboratorio de Microbiología de la Red de Salud UC-CHRISTUS entre 2014-2015, y compararlas con las cepas estudiadas en 2004-2005. Métodos: Entre enero de 2014 y junio de 2015, se aislaron 459 cepas de P. aeruginosa provenientes de muestras clínicas. La susceptibilidad fue determinada por dilución en agar y a las cepas con susceptibilidad disminuida a carbapenémicos se les realizó test de carbaNP. Las cepas positivas fueron estudiadas por RPC para genes blaVIM, blaVIM-1, blaVIM-2, blaIMP, blaNDM, blaKPC, blaOXA y blaIMI. Se realizó en cepas seleccionadas electroforesis de campo pulsado. Resultados: De las 459 cepas estudiadas, 300 presentaban susceptibilidad disminuida a carbapenémicos (65,3%). De éstas, 183 fueron viables para estudio, correspondientes a 164 pacientes. El test de carbaNP fue positivo en 44 cepas de las 183 cepas (24%). Los genes de resistencia encontrados fueron: blaVIM-2 en 35 cepas, blaKPC-2+VIM-2 en 7 cepas y blaKPC-2 en 2 cepas. En las cepas blaKPC-2 se encontró relación clonal entre ellas. Conclusiones: Un 65,3% de P. aeruginosa presentó susceptibilidad disminuida a carbapenémicos, observándose que la presencia de carbapenemasas no es el principal mecanismo de resistencia. Además, se describe la emergencia en Chile de cepas de P. aeruginosa con carbapenemasas del tipo KPC-2 sola o en combinación con VIM-2.
Abstract Background: Pseudomonas aeruginosa is a relevant infectious agent affecting patients within health care setting; this situation is worsening with the appearance of strains resistance to carbapenems. Aims: To study carbapenemase production in P. aeruginosa with decreased susceptibility to carbapenems processed in the microbiology laboratory of the Health Network UC-CHRISTUS in 2014-2015 and compare them with the strains studied in 2004-2005. Methods: Between January 2014 and June 2015, 459 strains of P. aeruginosa from clinical samples were isolated. Susceptibility was determined by dilution in agar and strains with reduced susceptibility to carbapenems were tested for carbaNP. Positive strains were studied by PCR for blaVIM, blaVIM-1, blaVIM-2, blaIMP, blaNDM, blaKPC, blaOXA and blaIMI genes. Pulsed field electrophoresis was performed on selected strains. Results: From 459 strains studied, 300 had reduced susceptibility to carbapenems (65.3%). Of these, 183 were viable for study, corresponding to 164 patients. The carbaNP test was positive in 44 strains of the 183 strains (24%). The resistance genes found were: blaVIM-2 in 35 strains, blaKPC-2+VIM-2 in 7 strains and blaKPC-2 in 2 strains. In the blaKPC-2 strains clonal relation between them was found. Conclusions: A 65.3% of P. aeruginosa presented decreased susceptibility to carbapenems being the presence of carbapenemases not the main resistance mechanism. In addition, the emergence in Chile of P. aeruginosa strains with bla of the KPC-2 type alone or in combination with VIM-2 is described.
Assuntos
Humanos , Pseudomonas aeruginosa/genética , Carbapenêmicos/farmacologia , Proteínas de Bactérias/genética , beta-Lactamases , Testes de Sensibilidade Microbiana , Chile , Antibacterianos/farmacologiaRESUMO
BACKGROUND: Pseudomonas aeruginosa is a relevant infectious agent affecting patients within health care setting; this situation is worsening with the appearance of strains resistance to carbapenems. AIMS: To study carbapenemase production in P. aeruginosa with decreased susceptibility to carbapenems processed in the microbiology laboratory of the Health Network UC-CHRISTUS in 2014-2015 and compare them with the strains studied in 2004-2005. METHODS: Between January 2014 and June 2015, 459 strains of P. aeruginosa from clinical samples were isolated. Susceptibility was determined by dilution in agar and strains with reduced susceptibility to carbapenems were tested for carbaNP. Positive strains were studied by PCR for blaVIM, blaVIM-1, blaVIM-2, blaIMP, blaNDM, blaKPC, blaOXA and blaIMI genes. Pulsed field electrophoresis was performed on selected strains. RESULTS: From 459 strains studied, 300 had reduced susceptibility to carbapenems (65.3%). Of these, 183 were viable for study, corresponding to 164 patients. The carbaNP test was positive in 44 strains of the 183 strains (24%). The resistance genes found were: blaVIM-2 in 35 strains, blaKPC-2+VIM-2 in 7 strains and blaKPC-2 in 2 strains. In the blaKPC-2 strains clonal relation between them was found. CONCLUSIONS: A 65.3% of P. aeruginosa presented decreased susceptibility to carbapenems being the presence of carbapenemases not the main resistance mechanism. In addition, the emergence in Chile of P. aeruginosa strains with bla of the KPC-2 type alone or in combination with VIM-2 is described.