[Intravenous colistin in the treatment of infections due to pan-resistant Gram negative bacilli]. / Colistín en infecciones nosocomiales por bacilos gramnegativos pan-resistentes.

UNLABELLED: Emergence of panresistant gram negative bacilli has lead to the progressive reintroduction of intravenous colistin. AIM: To describe the clinical experience observed with this compound. METHODOLOGY: A retrospective analysis was performed for all treatments lasting >/= 48 hours. Medical records were analyzed to obtain clinical parameters and microbiological data, evaluate clinical response and evolution until discharge. MAIN RESULTS: 24 treatments lasting >/= 48 hours were applied between June 2005 and September 2006. Intravenous colistin was indicated to treat cases of ventilator-associated (VA) pneumonia (n = 10; 41.7%), abscess or collections (12.5%), bloodstream infections, non-VA pneumonia or urinary tract infections (4.2% each one, respectively). Treatment was initiated on average at 3.2 days (+/- 2.85) from diagnosis of infection. All courses were microbiologically-guided, and involved P. aeruginosa or A. baumannii isolates. Susceptibility was evaluated by E-test in 11 isolates (MIC90 3.6 nicrog/mL, range 0.38 to 4 microg/mL). One isolate was resistant to colistin (9%). A favorable response was observed in 12 treatments (50%) with a relapse in 5 cases (41.7%). Being treated for pneumonia was the only factor associated to failure, (p = 0.04) Eradication was documented in 8 cases (33.3%) and persistence in 11 (45.8%). In 5 cases a microbiological follow-up was not available. Survival at time of discharge was 45.5%. (n = 10) None of the treatment courses was associated with nefrotoxicity. CONCLUSIONS: Intravenous colistin is a safe compound useful to treat various nosocomial infections due to pan-resistant gram negative bacilli. Nonetheless, its clinical efficacy is limited, especially among patients treated for nosocomial pneumonia.

Colistín en infecciones nosocomiales por bacilos gramnegativos pan-resistentes / Intravenous colistin in the treatment of infections due to pan-resistant Gram negative bacilli

La emergencia de bacilos gramnegativos pan-resistentes ha obligado a la reutilización progresiva de colistín. Objetivo: Describir la experiencia clínica con este compuesto. Metodología: Se efectuó un análisis retrospectivo de todos los tratamientos con colistín endovenoso administrados por más de 48 horas, analizando datos clínicos, microbiológicos, la respuesta terapéutica y evolución hasta el egreso. Resultados: Se aplicaron 24 tratamientos entre junio de 2005 y septiembre de 2006. Colistín endovenoso fue utilizado en eventos de neumonía asociada a VM (n = 10; 41,7 por ciento), colecciones o abscesos (12,5 por ciento), bacteriemias, neumonía no asociada a VM e infección urinaria (4,2 por ciento cada una, respectivamente). El tratamiento fue iniciado en promedio a 3,2 (± 2,85) días desde el diagnóstico de infección. Todos los pacientes tenían infecciones por Pseudomonas aeruginosa o Acinetobacter baumannii. Se evaluó la susceptibilidad por E-test en once aislados (CIM90 3,6 µg/mL, rango 0,38 a 4 µg/mL). Una cepa (9 por ciento) presentó resistencia. Se observó una respuesta favorable en 50 por cientoo de los casos (n = 12) con recaída en cinco de estos casos (41,7 por ciento). El único factor asociado a fracaso fue la presencia de neumonía (p = 0,04). Se observó erradicación en ocho casos (33,3 por ciento) y persistencia en once (45,8 por ciento). En cinco casos el resultado microbiológico no fue evaluable. Sobrevivió a la hospitalización 45,5 por ciento de los pacientes (n = 10). No se observó nefrotoxicidad. Conclusiones: Colistín endovenoso es un compuesto seguro para el tratamiento de infecciones por bacilos gramnegativos pan-resistentes. Sin embargo, su eficacia terapéutica es limitada, especialmente, entre aquellos pacientes tratados por neumonía.

Emergence of panresistant gram negative bacilli has lead to the progressive reintroduction of intravenous colistin. Aim: To describe the clinical experience observed with this compound. Methodology: A retrospective analysis was performed for all treatments lasting ≥ 48 hours. Medical records were analyzed to obtain clinical parameters and microbiological data, evaluate clinical response and evolution until discharge. Main results: 24 treatments lasting ≥ 48 hours were applied between June 2005 and September 2006. Intravenous colistin was indicated to treat cases of ventilator-associated (VA) pneumonia (n = 10; 41.7 percent), abscess or collections (12.5 percent), bloodstream infections, non-VA pneumonia or urinary tract infections (4.2 percent each one, respectively). Treatment was initiated on average at 3.2 days (± 2.85) from diagnosis of infection. All courses were microbiologically-guided, and involved P. aeruginosa or A. baumannii isolates. Susceptibility was evaluated by E-test in 11 isolates (MIC90 3.6 µg/mL, range 0.38 to 4 µg/mL). One isolate was resistant to colistin (9 percent). A favorable response was observed in 12 treatments (50 percent) with a relapse in 5 cases (41.7 percent). Being treated for pneumonia was the only factor associated to failure, (p = 0.04) Eradication was documented in 8 cases (33.3 percent) and persistence in 11 (45.8 percent). In 5 cases a microbiological follow-up was not available. Survival at time of discharge was 45.5 percent. (n = 10) None of the treatment courses was associated with nefrotoxicity. Conclusions: Intravenous colistin is a safe compound useful to treat various nosocomial infections due to pan-resistant gram negative bacilli. Nonetheless, its clinical efficacy is limited, especially among patients treated for nosocomial pneumonia.