Estudio de la actividad comparativa in vitro de telitromicina en patógenos respiratorios adquiridos en la comunidad en 13 centros clínicos chilenos / In vitro activity of telithromycin against community acquired respiratory pathogens

Background: Telithromycin is a new ketolide antimicrobial, that can be useful for the treatment of respiratory infections. Aim: To compare in vitro activity of telithromycin against respiratory pathogens, isolated in outpatient clinics. Material and methods: Two hundred eighty strains isolated from patients with respiratory infections, were studied. The strains studied were S pneumoniae, penicillin sensitive (SPNS:57); intermediate (SPNI:35), resistant (SPNR:25); S pyogenes (SP:57); H influenzae (HIN 51); M catarrhalis (MC:25) and S aureus meticillin sensitive (SAUS:30). Minimal inhibitory concentration (MIC) by broth microdilution was studied for telitrhomycin and levofloxacin in all strains. Other antimicrobials studied, but not in all strains were erythromycin, clindamycin, trimetoprim sulphamethoxazole, oxacillin, amoxicillin-clavulanic acid and cefuroxime. Results: All strains were sensible to telithromycin at a concentration ¡4 µg/ml. MIC 90 and its range for SPNS was 0.03 µg/ml (¡0.004-0.12), for SPNI was 0.03 µg/ml (¡0.004-025), for SPNR was 0.06 µg/ml (¡0.004-0.25), for HIN was 2 µg/ml (0.12-4), for SP was 0.5 µg/ml (¡0.004-2), for MC was 0.5 µg/ml (0.06-2) and for SAU was 0.25 µg/ml (0.06-0.25). Conclusions: All studied pathogens were sensible to telithromycin in vitro. This antimicrobial is an alternative for the treatment of community acquired respiratory infections.

Uso de bacitracina, L-piroglutamil amilaridasa y aglutinación en el diagnóstico de streptococcus B-hemolítico / Bacitracin, L-piroglutamyl amilaridase use and agglutination in B-hemolytic streptococcus identification

La utilización de la hidrólisis de pirrolidonyl B naftalamida (PYR) para la identificación presuntiva de Streptococcus B hemolitico grupo A, fue comparada con la prueba de susceptibilidad a discos de bacitracina 0.04 U, usando el método de aglutinación como estándar. El 99,3 por ciento de los Streptococcus grupo A fue correctamente identificado con PYR y el 100 por ciento con la prueba de bacitracina; esta última dio falsos positivos en 83,9 por ciento de las cepas grupo G, 85,7 por ciento en el grupo C y 20 por ciento en el grupo B. Ambos métodos mostraron una alta sensibilidad para la identificación de Streptococcus grupo A y destaca la especificidad de la prueba de PYR (100 por ciento) con respecto a prueba de bacitracina (40,7 por ciento)