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Cefuroxime non-susceptibility in multidrug-resistant Klebsiella pneumoniae overexpressing ramA and acrA and expressing ompK35 at reduced levels.
Källman, Owe; Motakefi, Alma; Wretlind, Bengt; Kalin, Mats; Olsson-Liljequist, Barbro; Giske, Christian G.
Afiliación
  • Källman O; Clinical Microbiology, MTC, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden. owe.kallman@karolinska.se
J Antimicrob Chemother ; 62(5): 986-90, 2008 Nov.
Article en En | MEDLINE | ID: mdl-18647746
OBJECTIVES: The aims were to study if efflux and down-regulation of porins contribute to cefuroxime resistance in Klebsiella pneumoniae and to co-resistance to unrelated antibiotics. METHODS: Ten cefuroxime-non-susceptible but cefotaxime-susceptible blood culture isolates of K. pneumoniae and one multiply antibiotic-resistant (MAR) laboratory strain (selected by chloramphenicol) were examined. Transcription of the genes acrA, ompK35, ramA, marA and soxS was determined with quantitative RT-PCR. RESULTS: All clinical isolates and the MAR laboratory strain had similar antibiograms with non-susceptibility to cefuroxime, tigecycline, chloramphenicol and nalidixic acid. Phenylalanine arginine beta-naphthylamide (PAbetaN) increased susceptibility to tigecycline, chloramphenicol and nalidixic acid, but not to cefuroxime. Increased acrA transcription and decreased ompK35 transcription was seen in all strains. Increased ramA transcription was seen in all strains except one clinical isolate. CONCLUSIONS: This multidrug-resistant phenotype of K. pneumoniae is associated with increased acrA and ramA transcription and decreased ompK35 transcription. Since the cefuroxime resistance was not reversed by PAbetaN, it was probably attributable to decreased levels of OmpK35, rather than to efflux.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Proteínas Bacterianas / Cefuroxima / Porinas / Farmacorresistencia Bacteriana Múltiple / Klebsiella pneumoniae / Antibacterianos Límite: Humans Idioma: En Revista: J Antimicrob Chemother Año: 2008 Tipo del documento: Article País de afiliación: Suecia Pais de publicación: Reino Unido

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Proteínas Bacterianas / Cefuroxima / Porinas / Farmacorresistencia Bacteriana Múltiple / Klebsiella pneumoniae / Antibacterianos Límite: Humans Idioma: En Revista: J Antimicrob Chemother Año: 2008 Tipo del documento: Article País de afiliación: Suecia Pais de publicación: Reino Unido