ABSTRACT
From January 1990 to December 1999 six isolates of Listeria monocytogenes were recovered in Casablanca from blood and / or CSF from 5 neonates and one three years old child. These isolates were studied by serotyping, phage typing and pulsed field gel electrophoresis. Resistance to 10 antibiotics was determined by E test method . All the isolates belong to serotype 1/2 b, except one serotype 4b. All the isolates were phage untypable. Four profiles were obtained by pulsed field gel electrophoresis . All the isolates were susceptible to penicillin G, ampicillin , gentamycin , rifampin and cotrimoxazole . One isolate [serotype 1/2b] was resistant to tetracycline [CMI > 256 mg/L] and one isolate [serotype 4b] was multiresistant [erythromycin MIC = 8 mcg/ml, chloramphenicol MIC > 256 mg/L and tetracycline MIC > 256 mg/L]. These results confirm the interest of DNA based techniques for typing sporadic isolates and stress the need for continuous surveillance of antibiotic resistance since multiresistance may occur