Epidemiology and in vitro antimicrobial susceptibility of aerobic Actinomycetales in a clinical setting.

INTRODUCTION: The incidence of infections caused by aerobic actinomycetes is increasing. Recent changes in taxonomy and the variability in susceptibility patterns among species make necessary a proper identification and antibiotic susceptibility testing. MATERIAL AND METHODS: Fifty-three strains of aerobic actinomycetes were identified by MALDI-TOF MS using the VITEK MS Mycobacterium/Nocardia kit (bioMérieux, France) in a tertiary hospital in Spain during a six-year period. Antimicrobial susceptibility testing of the isolates was performed using the Sensititre Rapmycoi microdilution panel (Thermo Fisher Scientific, Massachusetts, USA). RESULTS: Forty strains of Nocardia spp. were identified in the study, being N. farcinica and N. cyriacigeorgica the most prevalent ones. All isolates were susceptible to linezolid and the resistance to amikacin was only observed in one isolate of Gordonia sputi. Resistance to cotrimoxazole was only found in five isolates. CONCLUSIONS: Routine identification and antimicrobial susceptibility testing of aerobic actinomycetes is advisable for an efficient identification of species and effective treatment.

Epidemiology and in vitro antimicrobial susceptibility of aerobic Actinomycetales in a clinical setting / Epidemiología y sensibilidad in vitro de especies de Actinomycetales aerobios en la rutina asistencial

Introduction: The incidence of infections caused by aerobic actinomycetes is increasing. Recent changes in taxonomy and the variability in susceptibility patterns among species make necessary a proper identification and antibiotic susceptibility testing. Material and methods: Fifty-three strains of aerobic actinomycetes were identified by MALDI-TOF MS using the VITEK MS Mycobacterium/Nocardia kit (bioMérieux, France) in a tertiary hospital in Spain during a six-year period. Antimicrobial susceptibility testing of the isolates was performed using the Sensititre Rapmycoi microdilution panel (Thermo Fisher Scientific, Massachusetts, USA). Results: Forty strains of Nocardia spp. were identified in the study, being N. farcinica and N. cyriacigeorgica the most prevalent ones. All isolates were susceptible to linezolid and the resistance to amikacin was only observed in one isolate of Gordonia sputi. Resistance to cotrimoxazole was only found in five isolates. Conclusions: Routine identification and antimicrobial susceptibility testing of aerobic actinomycetes is advisable for an efficient identification of species and effective treatment.(AU)

Introducción: La incidencia de infecciones por actinomicetos aerobios está aumentando. Los recientes cambios en la taxonomía y la variabilidad en la sensibilidad entre especies hacen necesaria una identificación y estudio de sensibilidad adecuados. Material y métodos: Se identificaron 53 cepas de actinomicetos aerobios mediante MALDI-TOF utilizando el kit VITEK-MS Mycobacterium/Nocardia (bioMérieux, Francia) en un hospital terciario español durante seis años. Los estudios de sensibilidad de los aislados se realizaron utilizando el panel de microdilución Sensititre Rapmycoi (Thermo Fisher Scientific, Massachusetts, EE. UU.). Resultados: Se identificaron 40 cepas de Nocardia spp., siendo Nocardia farcinica y Nocardia cyriacigeorgica las más prevalentes. Todos los aislados fueron sensibles a linezolid, y solo se detectó resistencia a amikacina en un aislado de Gordonia sputi. Solo se encontró resistencia al cotrimoxazol en cinco aislados. Conclusiones: Es aconsejable realizar la identificación de rutina y las pruebas de sensibilidad antimicrobiana de los actinomicetos aerobios para conseguir una identificación eficiente de las especies y un tratamiento eficaz.(AU)

Epidemiology and in vitro antimicrobial susceptibility of aerobic Actinomycetales in a clinical setting.

INTRODUCTION: The incidence of infections caused by aerobic actinomycetes is increasing. Recent changes in taxonomy and the variability in susceptibility patterns among species make necessary a proper identification and antibiotic susceptibility testing. MATERIAL AND METHODS: Fifty-three strains of aerobic actinomycetes were identified by MALDI-TOF MS using the VITEK MS Mycobacterium/Nocardia kit (bioMérieux, France) in a tertiary hospital in Spain during a six-year period. Antimicrobial susceptibility testing of the isolates was performed using the Sensititre Rapmycoi microdilution panel (Thermo Fisher Scientific, Massachusetts, USA). RESULTS: Forty strains of Nocardia spp. were identified in the study, being N. farcinica and N. cyriacigeorgica the most prevalent ones. All isolates were susceptible to linezolid and the resistance to amikacin was only observed in one isolate of Gordonia sputi. Resistance to cotrimoxazole was only found in five isolates. CONCLUSIONS: Routine identification and antimicrobial susceptibility testing of aerobic actinomycetes is advisable for an efficient identification of species and effective treatment.